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Sample records for causal approaches needed

  1. Perturbative gravity in the causal approach

    NASA Astrophysics Data System (ADS)

    Grigore, D. R.

    2010-01-01

    Quantum theory of the gravitation in the causal approach is studied up to the second order of perturbation theory in the causal approach. We emphasize the use of cohomology methods in this framework. After describing in detail the mathematical structure of the cohomology method we apply it in three different situations: (a) the determination of the most general expression of the interaction Lagrangian; (b) the proof of gauge invariance in the second order of perturbation theory for the pure gravity system—massless and massive; (c) the investigation of the arbitrariness of the second-order chronological products compatible with renormalization principles and gauge invariance (i.e. the renormalization problem in the second order of perturbation theory). In case (a) we investigate pure gravity systems and the interaction of massless gravity with matter (described by scalars and spinors) and massless Yang-Mills fields. We obtain a difference with respect to the classical field theory due to the fact that in quantum field theory one cannot enforce the divergenceless property on the vector potential and this spoils the divergenceless property of the usual energy-momentum tensor. To correct this one needs a supplementary ghost term in the interaction Lagrangian. In all three case, the computations are more simple than by the usual methods.

  2. The metagenomic approach and causality in virology

    PubMed Central

    Castrignano, Silvana Beres; Nagasse-Sugahara, Teresa Keico

    2015-01-01

    Nowadays, the metagenomic approach has been a very important tool in the discovery of new viruses in environmental and biological samples. Here we discuss how these discoveries may help to elucidate the etiology of diseases and the criteria necessary to establish a causal association between a virus and a disease. PMID:25902566

  3. Loop anomalies in the causal approach

    NASA Astrophysics Data System (ADS)

    Grigore, Dan-Radu

    2015-01-01

    We consider gauge models in the causal approach and study one-loop contributions to the chronological products and the anomalies they produce. We prove that in order greater than 4 there are no one-loop anomalies. Next we analyze one-loop anomalies in the second- and third-order of the perturbation theory. We prove that the even parity contributions (with respect to parity) do not produce anomalies; for the odd parity contributions we reobtain the well-known result.

  4. Clarity and causality needed in claims about Big Gods.

    PubMed

    Watts, Joseph; Bulbulia, Joseph; Gray, Russell D; Atkinson, Quentin D

    2016-01-01

    We welcome Norenzayan et al.'s claim that the prosocial effects of beliefs in supernatural agents extend beyond Big Gods. To date, however, supporting evidence has focused on the Abrahamic Big God, making generalisations difficult. We discuss a recent study that highlights the need for clarity about the causal path by which supernatural beliefs affect the evolution of big societies. PMID:26948745

  5. Causality

    NASA Astrophysics Data System (ADS)

    Pearl, Judea

    2000-03-01

    Written by one of the pre-eminent researchers in the field, this book provides a comprehensive exposition of modern analysis of causation. It shows how causality has grown from a nebulous concept into a mathematical theory with significant applications in the fields of statistics, artificial intelligence, philosophy, cognitive science, and the health and social sciences. Pearl presents a unified account of the probabilistic, manipulative, counterfactual and structural approaches to causation, and devises simple mathematical tools for analyzing the relationships between causal connections, statistical associations, actions and observations. The book will open the way for including causal analysis in the standard curriculum of statistics, artifical intelligence, business, epidemiology, social science and economics. Students in these areas will find natural models, simple identification procedures, and precise mathematical definitions of causal concepts that traditional texts have tended to evade or make unduly complicated. This book will be of interest to professionals and students in a wide variety of fields. Anyone who wishes to elucidate meaningful relationships from data, predict effects of actions and policies, assess explanations of reported events, or form theories of causal understanding and causal speech will find this book stimulating and invaluable.

  6. A General Approach to Causal Mediation Analysis

    ERIC Educational Resources Information Center

    Imai, Kosuke; Keele, Luke; Tingley, Dustin

    2010-01-01

    Traditionally in the social sciences, causal mediation analysis has been formulated, understood, and implemented within the framework of linear structural equation models. We argue and demonstrate that this is problematic for 3 reasons: the lack of a general definition of causal mediation effects independent of a particular statistical model, the…

  7. A causal net approach to relativistic quantum mechanics

    NASA Astrophysics Data System (ADS)

    Bateson, R. D.

    2012-05-01

    In this paper we discuss a causal network approach to describing relativistic quantum mechanics. Each vertex on the causal net represents a possible point event or particle observation. By constructing the simplest causal net based on Reichenbach-like conjunctive forks in proper time we can exactly derive the 1+1 dimension Dirac equation for a relativistic fermion and correctly model quantum mechanical statistics. Symmetries of the net provide various quantum mechanical effects such as quantum uncertainty and wavefunction, phase, spin, negative energy states and the effect of a potential. The causal net can be embedded in 3+1 dimensions and is consistent with the conventional Dirac equation. In the low velocity limit the causal net approximates to the Schrodinger equation and Pauli equation for an electromagnetic field. Extending to different momentum states the net is compatible with the Feynman path integral approach to quantum mechanics that allows calculation of well known quantum phenomena such as diffraction.

  8. Subjective spacetime derived from a causal histories approach

    NASA Astrophysics Data System (ADS)

    Gunji, Yukio-Pegio; Haruna, Taichi; Uragami, Daisuke; Nishikawa, Asaki

    2009-10-01

    The internal description of spacetime can reveal ambiguity regarding an observer’s perception of the present, where an observer can refer to the present as if he were outside spacetime while actually existing in the present. This ambiguity can be expressed as the compatibility between an element and a set, and is here called a/{a}-compatibility. We describe a causal set as a lattice and a causal history as a quotient lattice, and implement the a/{a}-compatibility in the framework of a causal histories approach. This leads to a perpetual change of a pair of causal set and causal history, and can be used to describe subjective spacetime including the déjà vu experience and/or schizophrenic time.

  9. A Complex Systems Approach to Causal Discovery in Psychiatry

    PubMed Central

    Saxe, Glenn N.; Statnikov, Alexander; Fenyo, David; Ren, Jiwen; Li, Zhiguo; Prasad, Meera; Wall, Dennis; Bergman, Nora; Briggs, Ernestine C.; Aliferis, Constantin

    2016-01-01

    Conventional research methodologies and data analytic approaches in psychiatric research are unable to reliably infer causal relations without experimental designs, or to make inferences about the functional properties of the complex systems in which psychiatric disorders are embedded. This article describes a series of studies to validate a novel hybrid computational approach–the Complex Systems-Causal Network (CS-CN) method–designed to integrate causal discovery within a complex systems framework for psychiatric research. The CS-CN method was first applied to an existing dataset on psychopathology in 163 children hospitalized with injuries (validation study). Next, it was applied to a much larger dataset of traumatized children (replication study). Finally, the CS-CN method was applied in a controlled experiment using a ‘gold standard’ dataset for causal discovery and compared with other methods for accurately detecting causal variables (resimulation controlled experiment). The CS-CN method successfully detected a causal network of 111 variables and 167 bivariate relations in the initial validation study. This causal network had well-defined adaptive properties and a set of variables was found that disproportionally contributed to these properties. Modeling the removal of these variables resulted in significant loss of adaptive properties. The CS-CN method was successfully applied in the replication study and performed better than traditional statistical methods, and similarly to state-of-the-art causal discovery algorithms in the causal detection experiment. The CS-CN method was validated, replicated, and yielded both novel and previously validated findings related to risk factors and potential treatments of psychiatric disorders. The novel approach yields both fine-grain (micro) and high-level (macro) insights and thus represents a promising approach for complex systems-oriented research in psychiatry. PMID:27028297

  10. Wess-Zumino model in the causal approach

    NASA Astrophysics Data System (ADS)

    Grigore, D. R.

    2001-07-01

    The Wess Zumino model is analysed in the framework of the causal approach of Epstein Glaser. The condition of invariance with respect to supersymmetry transformations is similar to gauge invariance in the Zürich formulation. We prove that this invariance condition can be implemented in all orders of perturbation theory, i.e. the anomalies are absent in all orders. This result is of a purely algebraic nature. We work consistently in the quantum framework based on the Bogoliubov axioms of perturbation theory, so no Grassmann variables are necessary.

  11. A developmental approach to learning causal models for cyber security

    NASA Astrophysics Data System (ADS)

    Mugan, Jonathan

    2013-05-01

    To keep pace with our adversaries, we must expand the scope of machine learning and reasoning to address the breadth of possible attacks. One approach is to employ an algorithm to learn a set of causal models that describes the entire cyber network and each host end node. Such a learning algorithm would run continuously on the system and monitor activity in real time. With a set of causal models, the algorithm could anticipate novel attacks, take actions to thwart them, and predict the second-order effects flood of information, and the algorithm would have to determine which streams of that flood were relevant in which situations. This paper will present the results of efforts toward the application of a developmental learning algorithm to the problem of cyber security. The algorithm is modeled on the principles of human developmental learning and is designed to allow an agent to learn about the computer system in which it resides through active exploration. Children are flexible learners who acquire knowledge by actively exploring their environment and making predictions about what they will find,1, 2 and our algorithm is inspired by the work of the developmental psychologist Jean Piaget.3 Piaget described how children construct knowledge in stages and learn new concepts on top of those they already know. Developmental learning allows our algorithm to focus on subsets of the environment that are most helpful for learning given its current knowledge. In experiments, the algorithm was able to learn the conditions for file exfiltration and use that knowledge to protect sensitive files.

  12. Nanoparticles in the environment: assessment using the causal diagram approach.

    PubMed

    Smita, Suchi; Gupta, Shailendra K; Bartonova, Alena; Dusinska, Maria; Gutleb, Arno C; Rahman, Qamar

    2012-01-01

    Nanoparticles (NPs) cause concern for health and safety as their impact on the environment and humans is not known. Relatively few studies have investigated the toxicological and environmental effects of exposure to naturally occurring NPs (NNPs) and man-made or engineered NPs (ENPs) that are known to have a wide variety of effects once taken up into an organism. A review of recent knowledge (between 2000-2010) on NP sources, and their behaviour, exposure and effects on the environment and humans was performed. An integrated approach was used to comprise available scientific information within an interdisciplinary logical framework, to identify knowledge gaps and to describe environment and health linkages for NNPs and ENPs. The causal diagram has been developed as a method to handle the complexity of issues on NP safety, from their exposure to the effects on the environment and health. It gives an overview of available scientific information starting with common sources of NPs and their interactions with various environmental processes that may pose threats to both human health and the environment. Effects of NNPs on dust cloud formation and decrease in sunlight intensity were found to be important environmental changes with direct and indirect implication in various human health problems. NNPs and ENPs exposure and their accumulation in biological matrices such as microbiota, plants and humans may result in various adverse effects. The impact of some NPs on human health by ROS generation was found to be one of the major causes to develop various diseases. A proposed cause-effects diagram for NPs is designed considering both NNPs and ENPs. It represents a valuable information package and user-friendly tool for various stakeholders including students, researchers and policy makers, to better understand and communicate on issues related to NPs. PMID:22759495

  13. Nanoparticles in the environment: assessment using the causal diagram approach

    PubMed Central

    2012-01-01

    Nanoparticles (NPs) cause concern for health and safety as their impact on the environment and humans is not known. Relatively few studies have investigated the toxicological and environmental effects of exposure to naturally occurring NPs (NNPs) and man-made or engineered NPs (ENPs) that are known to have a wide variety of effects once taken up into an organism. A review of recent knowledge (between 2000-2010) on NP sources, and their behaviour, exposure and effects on the environment and humans was performed. An integrated approach was used to comprise available scientific information within an interdisciplinary logical framework, to identify knowledge gaps and to describe environment and health linkages for NNPs and ENPs. The causal diagram has been developed as a method to handle the complexity of issues on NP safety, from their exposure to the effects on the environment and health. It gives an overview of available scientific information starting with common sources of NPs and their interactions with various environmental processes that may pose threats to both human health and the environment. Effects of NNPs on dust cloud formation and decrease in sunlight intensity were found to be important environmental changes with direct and indirect implication in various human health problems. NNPs and ENPs exposure and their accumulation in biological matrices such as microbiota, plants and humans may result in various adverse effects. The impact of some NPs on human health by ROS generation was found to be one of the major causes to develop various diseases. A proposed cause-effects diagram for NPs is designed considering both NNPs and ENPs. It represents a valuable information package and user-friendly tool for various stakeholders including students, researchers and policy makers, to better understand and communicate on issues related to NPs. PMID:22759495

  14. Hindsight bias and causal reasoning: a minimalist approach.

    PubMed

    Yopchick, Jennelle E; Kim, Nancy S

    2012-02-01

    What factors contribute to hindsight bias, the phenomenon whereby the known outcome of an event appears obvious only after the fact? The Causal Model Theory (CMT) of hindsight bias (Nestler et al. in Soc Psychol 39:182-188, 2008a; in J Expl Psychol: Learn Mem Cog 34:1043-1054, 2008b; Pezzo in Mem 11:421-441, 2003; Wasserman et al. in Pers Soc Psychol Bull 17:30-35, 1991) posits that hindsight bias can occur when people have the opportunity to identify potential causal antecedents and evaluate whether they could have led to the outcome. Two experiments incorporating highly controlled minimalist scenarios supported the CMT. As predicted by the CMT, hindsight bias occurred when the causal factor explained the actual outcome better than the alternative outcome, and reverse hindsight bias occurred when the causal factor explained the alternative outcome better than the actual outcome. Moreover, we found new evidence that outcome knowledge alone was insufficient to elicit hindsight bias in the absence of a potential causal antecedent. Implications for future directions in hindsight bias research are discussed. PMID:21912981

  15. MicroRNA in late lung development and bronchopulmonary dysplasia: the need to demonstrate causality.

    PubMed

    Nardiello, Claudio; Morty, Rory E

    2016-12-01

    MicroRNA are emerging as powerful regulators of cell differentiation and tissue and organ development. Several microRNA have been described to play a role in branching morphogenesis, a key step in early lung development. However, considerably less attention has been paid to microRNA as regulators of the process of secondary septation, which drives lung alveolarization during late lung development. Secondary septation is severely perturbed in bronchopulmonary dysplasia (BPD), a common complication of preterm birth characterized by blunted alveolarization. A number of studies to date have reported microRNA microarray screens in animal models of BPD; however, only two studies have attempted to demonstrate causality. Although the expression of miR-150 was altered in experimental BPD, a miR-150(-/-) knockout mouse did not exhibit appreciable protection in a BPD animal model. Similarly, while the expression of miR-489 in the lung was reduced in clinical and experimental BPD, antagomiR and over-expression approaches could not validate a role for miR-489 in the impaired alveolarization associated with experimental BPD. This mini-review aims to highlight microRNA that have been revealed by multiple microarray studies to be potential causal players in normal and pathological alveolarization. Additionally, the challenges faced in attempting to demonstrate a causal role for microRNA in lung alveolarization are discussed. These include the tremendous variability in the animal models employed, and the limitations and advantages offered by the available tools, including antagomiRs and approaches for the validation of a specific microRNA-mRNA interaction during lung alveolarization. PMID:27216745

  16. Dark matter perturbations and viscosity: A causal approach

    NASA Astrophysics Data System (ADS)

    Acquaviva, Giovanni; John, Anslyn; Pénin, Aurélie

    2016-08-01

    The inclusion of dissipative effects in cosmic fluids modifies their clustering properties and could have observable effects on the formation of large-scale structures. We analyze the evolution of density perturbations of cold dark matter endowed with causal bulk viscosity. The perturbative analysis is carried out in the Newtonian approximation and the bulk viscosity is described by the causal Israel-Stewart (IS) theory. In contrast to the noncausal Eckart theory, we obtain a third-order evolution equation for the density contrast that depends on three free parameters. For certain parameter values, the density contrast and growth factor in IS mimic their behavior in Λ CDM when z ≥1 . Interestingly, and contrary to intuition, certain sets of parameters lead to an increase of the clustering.

  17. Statistical Approaches for Enhancing Causal Interpretation of the M to Y Relation in Mediation Analysis

    PubMed Central

    MacKinnon, David P.; Pirlott, Angela G.

    2016-01-01

    Statistical mediation methods provide valuable information about underlying mediating psychological processes, but the ability to infer that the mediator variable causes the outcome variable is more complex than widely known. Researchers have recently emphasized how violating assumptions about confounder bias severely limits causal inference of the mediator to dependent variable relation. Our article describes and addresses these limitations by drawing on new statistical developments in causal mediation analysis. We first review the assumptions underlying causal inference and discuss three ways to examine the effects of confounder bias when assumptions are violated. We then describe four approaches to address the influence of confounding variables and enhance causal inference, including comprehensive structural equation models, instrumental variable methods, principal stratification, and inverse probability weighting. Our goal is to further the adoption of statistical methods to enhance causal inference in mediation studies. PMID:25063043

  18. A Novel Approach for Identifying Causal Models of Complex Diseases from Family Data

    PubMed Central

    Park, Leeyoung; Kim, Ju H.

    2015-01-01

    Causal models including genetic factors are important for understanding the presentation mechanisms of complex diseases. Familial aggregation and segregation analyses based on polygenic threshold models have been the primary approach to fitting genetic models to the family data of complex diseases. In the current study, an advanced approach to obtaining appropriate causal models for complex diseases based on the sufficient component cause (SCC) model involving combinations of traditional genetics principles was proposed. The probabilities for the entire population, i.e., normal–normal, normal–disease, and disease–disease, were considered for each model for the appropriate handling of common complex diseases. The causal model in the current study included the genetic effects from single genes involving epistasis, complementary gene interactions, gene–environment interactions, and environmental effects. Bayesian inference using a Markov chain Monte Carlo algorithm (MCMC) was used to assess of the proportions of each component for a given population lifetime incidence. This approach is flexible, allowing both common and rare variants within a gene and across multiple genes. An application to schizophrenia data confirmed the complexity of the causal factors. An analysis of diabetes data demonstrated that environmental factors and gene–environment interactions are the main causal factors for type II diabetes. The proposed method is effective and useful for identifying causal models, which can accelerate the development of efficient strategies for identifying causal factors of complex diseases. PMID:25701286

  19. Renewable Energy Consumption and Economic Growth in Nine OECD Countries: Bounds Test Approach and Causality Analysis

    PubMed Central

    Hung-Pin, Lin

    2014-01-01

    The purpose of this paper is to investigate the short-run and long-run causality between renewable energy (RE) consumption and economic growth (EG) in nine OECD countries from the period between 1982 and 2011. To examine the linkage, this paper uses the autoregressive distributed lag (ARDL) bounds testing approach of cointegration test and vector error-correction models to test the causal relationship between variables. The co-integration and causal relationships are found in five countries—United States of America (USA), Japan, Germany, Italy, and United Kingdom (UK). The overall results indicate that (1) a short-run unidirectional causality runs from EG to RE in Italy and UK; (2) long-run unidirectional causalities run from RE to EG for Germany, Italy, and UK; (3) a long-run unidirectional causality runs from EG to RE in USA, and Japan; (4) both long-run and strong unidirectional causalities run from RE to EG for Germany and UK; and (5) Finally, both long-run and strong unidirectional causalities run from EG to RE in only USA. Further evidence reveals that policies for renewable energy conservation may have no impact on economic growth in France, Denmark, Portugal, and Spain. PMID:24558343

  20. The structure of the anomalies of gauge theories in the causal approach

    NASA Astrophysics Data System (ADS)

    Grigore, D. R.

    2002-02-01

    We consider the gauge invariance of the standard Yang-Mills model in the framework of the causal approach of Epstein-Glaser and Scharf and determine the generic form of the anomalies. The method used is based on the Epstein-Glaser approach to renormalization theory. In the case of quantum electrodynamics we obtain quite easily the absence of anomalies in all orders.

  1. Exploring manual asymmetries during grasping: a dynamic causal modeling approach

    PubMed Central

    Begliomini, Chiara; Sartori, Luisa; Miotto, Diego; Stramare, Roberto; Motta, Raffaella; Castiello, Umberto

    2015-01-01

    Recording of neural activity during grasping actions in macaques showed that grasp-related sensorimotor transformations are accomplished in a circuit constituted by the anterior part of the intraparietal sulcus (AIP), the ventral (F5) and the dorsal (F2) region of the premotor area. In humans, neuroimaging studies have revealed the existence of a similar circuit, involving the putative homolog of macaque areas AIP, F5, and F2. These studies have mainly considered grasping movements performed with the right dominant hand and only a few studies have measured brain activity associated with a movement performed with the left non-dominant hand. As a consequence of this gap, how the brain controls for grasping movement performed with the dominant and the non-dominant hand still represents an open question. A functional magnetic resonance imaging (fMRI) experiment has been conducted, and effective connectivity (dynamic causal modeling, DCM) was used to assess how connectivity among grasping-related areas is modulated by hand (i.e., left and right) during the execution of grasping movements toward a small object requiring precision grasping. Results underlined boosted inter-hemispheric couplings between dorsal premotor cortices during the execution of movements performed with the left rather than the right dominant hand. More specifically, they suggest that the dorsal premotor cortices may play a fundamental role in monitoring the configuration of fingers when grasping movements are performed by either the right and the left hand. This role becomes particularly evident when the hand less-skilled (i.e., the left hand) to perform such action is utilized. The results are discussed in light of recent theories put forward to explain how parieto-frontal connectivity is modulated by the execution of prehensile movements. PMID:25759677

  2. A Novel Extended Granger Causal Model Approach Demonstrates Brain Hemispheric Differences during Face Recognition Learning

    PubMed Central

    Ge, Tian; Kendrick, Keith M.; Feng, Jianfeng

    2009-01-01

    Two main approaches in exploring causal relationships in biological systems using time-series data are the application of Dynamic Causal model (DCM) and Granger Causal model (GCM). These have been extensively applied to brain imaging data and are also readily applicable to a wide range of temporal changes involving genes, proteins or metabolic pathways. However, these two approaches have always been considered to be radically different from each other and therefore used independently. Here we present a novel approach which is an extension of Granger Causal model and also shares the features of the bilinear approximation of Dynamic Causal model. We have first tested the efficacy of the extended GCM by applying it extensively in toy models in both time and frequency domains and then applied it to local field potential recording data collected from in vivo multi-electrode array experiments. We demonstrate face discrimination learning-induced changes in inter- and intra-hemispheric connectivity and in the hemispheric predominance of theta and gamma frequency oscillations in sheep inferotemporal cortex. The results provide the first evidence for connectivity changes between and within left and right inferotemporal cortexes as a result of face recognition learning. PMID:19936225

  3. Scale invariance in the causal approach to renormalization theory

    NASA Astrophysics Data System (ADS)

    Grigore, Dan R.

    2001-06-01

    The dilation invariance is studied in the framework of Epstein-Glaser approach to renormalization theory. Some analogues of the Callan-Symanzik equations are found and they are applied to the scalar field theory and to Yang-Mills models. We find the interesting result that, if all fields of the theory have zero masses, then from purely cohomological consideration, one can obtain the anomalous terms of logarithmic type.

  4. A causal model of positive health practices: the relationship between approach and replication.

    PubMed

    Yarcheski, A; Mahon, N E

    1989-01-01

    This study supports the position that causal models developed a priori preclude replication with varied samples. Based on a critique of a study of positive health practices among adults (Muhlenkamp & Sayles, 1986), a causal model of positive health practices for adolescents was developed a priori from a theoretical formulation. Using data from a sample of 165 adolescents who responded to the Personal Lifestyle Questionnaire, the Rosenberg Self-Esteem Scale, Part 2 of the Personal Resource Questionnaire which measures a social support system, and a demographic data sheet, the intercorrelations among the study variables were analyzed using correlation coefficients. The causal model was then tested with the adolescent data using the LISREL VI program. The results showed a relatively good fit of the model to the data via a number of indicators. The model was then applied to data published from adults (Muhlenkamp & Sayles) using the LISREL VI program. The results indicated that there was a relatively poor fit of the model to the adult data, thus demonstrating the problem of replicating causal models with varied samples when the correct approach to causal modeling is used. The discussion focuses on theoretical and methodological reasons for the findings. PMID:2928152

  5. Spatial-temporal causal modeling: a data centric approach to climate change attribution (Invited)

    NASA Astrophysics Data System (ADS)

    Lozano, A. C.

    2010-12-01

    Attribution of climate change has been predominantly based on simulations using physical climate models. These approaches rely heavily on the employed models and are thus subject to their shortcomings. Given the physical models’ limitations in describing the complex system of climate, we propose an alternative approach to climate change attribution that is data centric in the sense that it relies on actual measurements of climate variables and human and natural forcing factors. We present a novel class of methods to infer causality from spatial-temporal data, as well as a procedure to incorporate extreme value modeling into our methodology in order to address the attribution of extreme climate events. We develop a collection of causal modeling methods using spatio-temporal data that combine graphical modeling techniques with the notion of Granger causality. “Granger causality” is an operational definition of causality from econometrics, which is based on the premise that if a variable causally affects another, then the past values of the former should be helpful in predicting the future values of the latter. In its basic version, our methodology makes use of the spatial relationship between the various data points, but treats each location as being identically distributed and builds a unique causal graph that is common to all locations. A more flexible framework is then proposed that is less restrictive than having a single causal graph common to all locations, while avoiding the brittleness due to data scarcity that might arise if one were to independently learn a different graph for each location. The solution we propose can be viewed as finding a middle ground by partitioning the locations into subsets that share the same causal structures and pooling the observations from all the time series belonging to the same subset in order to learn more robust causal graphs. More precisely, we make use of relationships between locations (e.g. neighboring

  6. Causal nexus between energy consumption and carbon dioxide emission for Malaysia using maximum entropy bootstrap approach.

    PubMed

    Gul, Sehrish; Zou, Xiang; Hassan, Che Hashim; Azam, Muhammad; Zaman, Khalid

    2015-12-01

    This study investigates the relationship between energy consumption and carbon dioxide emission in the causal framework, as the direction of causality remains has a significant policy implication for developed and developing countries. The study employed maximum entropy bootstrap (Meboot) approach to examine the causal nexus between energy consumption and carbon dioxide emission using bivariate as well as multivariate framework for Malaysia, over a period of 1975-2013. This is a unified approach without requiring the use of conventional techniques based on asymptotical theory such as testing for possible unit root and cointegration. In addition, it can be applied in the presence of non-stationary of any type including structural breaks without any type of data transformation to achieve stationary. Thus, it provides more reliable and robust inferences which are insensitive to time span as well as lag length used. The empirical results show that there is a unidirectional causality running from energy consumption to carbon emission both in the bivariate model and multivariate framework, while controlling for broad money supply and population density. The results indicate that Malaysia is an energy-dependent country and hence energy is stimulus to carbon emissions. PMID:26282441

  7. The Reactive-Causal Architecture: Introducing an Emotion Model along with Theories of Needs

    NASA Astrophysics Data System (ADS)

    Aydin, Ali Orhan; Orgun, Mehmet Ali

    In the entertainment application area, one of the major aims is to develop believable agents. To achieve this aim, agents should be highly autonomous, situated, flexible, and display affect. The Reactive-Causal Architecture (ReCau) is proposed to simulate these core attributes. In its current form, ReCau cannot explain the effects of emotions on intelligent behaviour. This study aims is to further improve the emotion model of ReCau to explain the effects of emotions on intelligent behaviour. This improvement allows ReCau to be emotional to support the development of believable agents.

  8. Trajectories and causal phase-space approach to relativistic quantum mechanics

    SciTech Connect

    Holland, P.R.; Kyprianidis, A.; Vigier, J.P.

    1987-05-01

    The authors analyze phase-space approaches to relativistic quantum mechanics from the viewpoint of the causal interpretation. In particular, they discuss the canonical phase space associated with stochastic quantization, its relation to Hilbert space, and the Wigner-Moyal formalism. They then consider the nature of Feynman paths, and the problem of nonlocality, and conclude that a perfectly consistent relativistically covariant interpretation of quantum mechanics which retains the notion of particle trajectory is possible.

  9. Many replications do not causal inferences make: the need for critical replications to test competing explanations of nonrandomized studies.

    PubMed

    Larzelere, Robert E; Cox, Ronald B; Swindle, Taren M

    2015-05-01

    Although direct replications are ideal for randomized studies, areas of psychological science that lack randomized studies should incorporate Rosenbaum's (2001) distinction between trivial and nontrivial replications, relabeled herein as exact and critical replications. If exact replications merely repeat systematic biases, they cannot enhance cumulative progress in psychological science. In contrast, critical replications distinguish between competing explanations by using crucial tests to clarify the underlying causal influences. We illustrate this potential with examples from research on corrective actions by professionals (e.g., psychotherapy, Ritalin) and parents (e.g., spanking, homework assistance), where critical replications are needed to overcome the inherent selection bias due to corrective actions being triggered by children's symptoms. Purported causal effects must first prove to be replicable after plausible confounds such as selection bias are eliminated. Subsequent critical replications can then compare plausible alternative explanations of the average unbiased causal effect and of individual differences in those effects. We conclude that this type of systematic sequencing of critical replications has more potential for making the kinds of discriminations typical of cumulative progress in science than do exact replications alone, especially in areas where randomized studies are unavailable. PMID:25987516

  10. A Different Approach to Special Needs.

    ERIC Educational Resources Information Center

    Kennedy, Evelyn S.

    1985-01-01

    Methods of modifying home economics classes, specifically fashion and clothing design courses, for special needs students are discussed. Discusses the team approach to problem solving, interagency linkage to internship, student involvement, changes to ready-to-wear clothes for special needs, and information resources. (CT)

  11. An Isometric Dynamics for a Causal Set Approach to Discrete Quantum Gravity

    NASA Astrophysics Data System (ADS)

    Gudder, S.

    2015-12-01

    We consider a covariant causal set approach to discrete quantum gravity. We first review the microscopic picture of this approach. In this picture a universe grows one element at a time and its geometry is determined by a sequence of integers called the shell sequence. We next present the macroscopic picture which is described by a sequential growth process. We introduce a model in which the dynamics is governed by a quantum transition amplitude. The amplitude satisfies a stochastic and unitary condition and the resulting dynamics becomes isometric. We show that the dynamics preserves stochastic states. By "doubling down" on the dynamics we obtain a unitary group representation and a natural energy operator. These unitary operators are employed to define canonical position and momentum operators.

  12. The causal model approach to nutritional problems: an effective tool for research and action at the local level.

    PubMed Central

    Tonglet, R.; Mudosa, M.; Badashonderana, M.; Beghin, I.; Hennart, P.

    1992-01-01

    Reported are the results of a case study from Kirotshe rural health district, Northern Kivu, Zaire, where a workshop on the causal model approach to nutrition was organized in 1987. The model has since been used in the field for research design, training of health professionals, nutrition intervention, and community development. The rationale behind this approach is reviewed, the experience accumulated from Kirotshe district is described, and the ways in which the causal model contributes to comprehensive health and nutrition care are discussed. The broad range of possible policy implications of this approach underlines its usefulness for future action. PMID:1486667

  13. WWC Review of the Report "Looking beyond Enrollment: The Causal Effect of Need-Based Grants on College Access, Persistence, and Graduation." What Works Clearinghouse Single Study Review

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2014

    2014-01-01

    The 2013 study, "Looking Beyond Enrollment: The Causal Effect of Need-Based Grants on College Access, Persistence, and Graduation," examined whether eligibility for the Florida Student Access Grant (FSAG), a need-based grant for low-income students in Florida, affects college enrollment, credit accumulation, persistence over time in…

  14. Physician Educational Needs in Osteoporosis: An Approach to Needs Assessment.

    ERIC Educational Resources Information Center

    Lockyer, Jocelyn; Hanley, David; Fidler, Herta; Toews, John; Lysholm-Andrews, Elaine

    1998-01-01

    A literature review, focus groups (n=200), and questionnaire responses from 324 family physicians identified their learning needs related to osteoporosis. The three methods identified different learning issues, suggesting the importance of triangulation to ensure currency and relevance in continuing-education needs-assessment. (SK)

  15. Epidemiological causality.

    PubMed

    Morabia, Alfredo

    2005-01-01

    Epidemiological methods, which combine population thinking and group comparisons, can primarily identify causes of disease in populations. There is therefore a tension between our intuitive notion of a cause, which we want to be deterministic and invariant at the individual level, and the epidemiological notion of causes, which are invariant only at the population level. Epidemiologists have given heretofore a pragmatic solution to this tension. Causal inference in epidemiology consists in checking the logical coherence of a causality statement and determining whether what has been found grossly contradicts what we think we already know: how strong is the association? Is there a dose-response relationship? Does the cause precede the effect? Is the effect biologically plausible? Etc. This approach to causal inference can be traced back to the English philosophers David Hume and John Stuart Mill. On the other hand, the mode of establishing causality, devised by Jakob Henle and Robert Koch, which has been fruitful in bacteriology, requires that in every instance the effect invariably follows the cause (e.g., inoculation of Koch bacillus and tuberculosis). This is incompatible with epidemiological causality which has to deal with probabilistic effects (e.g., smoking and lung cancer), and is therefore invariant only for the population. PMID:16898206

  16. From Correlation to Causality: Statistical Approaches to Learning Regulatory Relationships in Large-Scale Biomolecular Investigations.

    PubMed

    Ness, Robert O; Sachs, Karen; Vitek, Olga

    2016-03-01

    Causal inference, the task of uncovering regulatory relationships between components of biomolecular pathways and networks, is a primary goal of many high-throughput investigations. Statistical associations between observed protein concentrations can suggest an enticing number of hypotheses regarding the underlying causal interactions, but when do such associations reflect the underlying causal biomolecular mechanisms? The goal of this perspective is to provide suggestions for causal inference in large-scale experiments, which utilize high-throughput technologies such as mass-spectrometry-based proteomics. We describe in nontechnical terms the pitfalls of inference in large data sets and suggest methods to overcome these pitfalls and reliably find regulatory associations. PMID:26731284

  17. Causal Inference in Public Health

    PubMed Central

    Glass, Thomas A.; Goodman, Steven N.; Hernán, Miguel A.; Samet, Jonathan M.

    2014-01-01

    Causal inference has a central role in public health; the determination that an association is causal indicates the possibility for intervention. We review and comment on the long-used guidelines for interpreting evidence as supporting a causal association and contrast them with the potential outcomes framework that encourages thinking in terms of causes that are interventions. We argue that in public health this framework is more suitable, providing an estimate of an action’s consequences rather than the less precise notion of a risk factor’s causal effect. A variety of modern statistical methods adopt this approach. When an intervention cannot be specified, causal relations can still exist, but how to intervene to change the outcome will be unclear. In application, the often-complex structure of causal processes needs to be acknowledged and appropriate data collected to study them. These newer approaches need to be brought to bear on the increasingly complex public health challenges of our globalized world. PMID:23297653

  18. A conditional Granger causality model approach for group analysis in functional MRI

    PubMed Central

    Zhou, Zhenyu; Wang, Xunheng; Klahr, Nelson J.; Liu, Wei; Arias, Diana; Liu, Hongzhi; von Deneen, Karen M.; Wen, Ying; Lu, Zuhong; Xu, Dongrong; Liu, Yijun

    2011-01-01

    Granger causality model (GCM) derived from multivariate vector autoregressive models of data has been employed for identifying effective connectivity in the human brain with functional MR imaging (fMRI) and to reveal complex temporal and spatial dynamics underlying a variety of cognitive processes. In the most recent fMRI effective connectivity measures, pairwise GCM has commonly been applied based on single voxel values or average values from special brain areas at the group level. Although a few novel conditional GCM methods have been proposed to quantify the connections between brain areas, our study is the first to propose a viable standardized approach for group analysis of an fMRI data with GCM. To compare the effectiveness of our approach with traditional pairwise GCM models, we applied a well-established conditional GCM to pre-selected time series of brain regions resulting from general linear model (GLM) and group spatial kernel independent component analysis (ICA) of an fMRI dataset in the temporal domain. Datasets consisting of one task-related and one resting-state fMRI were used to investigate connections among brain areas with the conditional GCM method. With the GLM detected brain activation regions in the emotion related cortex during the block design paradigm, the conditional GCM method was proposed to study the causality of the habituation between the left amygdala and pregenual cingulate cortex during emotion processing. For the resting-state dataset, it is possible to calculate not only the effective connectivity between networks but also the heterogeneity within a single network. Our results have further shown a particular interacting pattern of default mode network (DMN) that can be characterized as both afferent and efferent influences on the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC). These results suggest that the conditional GCM approach based on a linear multivariate vector autoregressive (MVAR) model can achieve

  19. There aren't plenty more fish in the sea: a causal network approach.

    PubMed

    Nikolic, Milena; Lagnado, David A

    2015-11-01

    The current research investigated how lay representations of the causes of an environmental problem may underlie individuals' reasoning about the issue. Naïve participants completed an experiment that involved two main tasks. The causal diagram task required participants to depict the causal relations between a set of factors related to overfishing and to estimate the strength of these relations. The counterfactual task required participants to judge the effect of counterfactual suppositions based on the diagrammed factors. We explored two major questions: (1) what is the relation between individual causal models and counterfactual judgments? Consistent with previous findings (e.g., Green et al., 1998, Br. J. Soc. Psychology, 37, 415), these judgments were best explained by a combination of the strength of both direct and indirect causal paths. (2) To what extent do people use two-way causal thinking when reasoning about an environmental problem? In contrast to previous research (e.g., White, 2008, Appl. Cogn. Psychology, 22, 559), analyses based on individual causal networks revealed the presence of numerous feedback loops. The studies support the value of analysing individual causal models in contrast to consensual representations. Theoretical and practical implications are discussed in relation to causal reasoning as well as environmental psychology. PMID:25597224

  20. A Causal Modelling Approach to the Development of Theory-Based Behaviour Change Programmes for Trial Evaluation

    ERIC Educational Resources Information Center

    Hardeman, Wendy; Sutton, Stephen; Griffin, Simon; Johnston, Marie; White, Anthony; Wareham, Nicholas J.; Kinmonth, Ann Louise

    2005-01-01

    Theory-based intervention programmes to support health-related behaviour change aim to increase health impact and improve understanding of mechanisms of behaviour change. However, the science of intervention development remains at an early stage. We present a causal modelling approach to developing complex interventions for evaluation in…

  1. Hume, Mill, Hill, and the sui generis epidemiologic approach to causal inference.

    PubMed

    Morabia, Alfredo

    2013-11-15

    The epidemiologic approach to causal inference (i.e., Hill's viewpoints) consists of evaluating potential causes from the following 2, noncumulative angles: 1) established results from comparative, observational, or experimental epidemiologic studies; and 2) reviews of nonepidemiologic evidence. It does not involve statements of statistical significance. The philosophical roots of Hill's viewpoints are unknown. Superficially, they seem to descend from the ideas of Hume and Mill. Hill's viewpoints, however, use a different kind of evidence and have different purposes than do Hume's rules or Mill's system of logic. In a nutshell, Hume ignores comparative evidence central to Hill's viewpoints. Mill's logic disqualifies as invalid nonexperimental evidence, which forms the bulk of epidemiologic findings reviewed from Hill's viewpoints. The approaches by Hume and Mill cannot corroborate successful implementations of Hill's viewpoints. Besides Hume and Mill, the epidemiologic literature is clueless about a plausible, pre-1965 philosophical origin of Hill's viewpoints. Thus, Hill's viewpoints may be philosophically novel, sui generis, still waiting to be validated and justified. PMID:24071010

  2. Hume, Mill, Hill, and the Sui Generis Epidemiologic Approach to Causal Inference

    PubMed Central

    Morabia, Alfredo

    2013-01-01

    The epidemiologic approach to causal inference (i.e., Hill's viewpoints) consists of evaluating potential causes from the following 2, noncumulative angles: 1) established results from comparative, observational, or experimental epidemiologic studies; and 2) reviews of nonepidemiologic evidence. It does not involve statements of statistical significance. The philosophical roots of Hill's viewpoints are unknown. Superficially, they seem to descend from the ideas of Hume and Mill. Hill's viewpoints, however, use a different kind of evidence and have different purposes than do Hume's rules or Mill's system of logic. In a nutshell, Hume ignores comparative evidence central to Hill's viewpoints. Mill's logic disqualifies as invalid nonexperimental evidence, which forms the bulk of epidemiologic findings reviewed from Hill's viewpoints. The approaches by Hume and Mill cannot corroborate successful implementations of Hill's viewpoints. Besides Hume and Mill, the epidemiologic literature is clueless about a plausible, pre-1965 philosophical origin of Hill's viewpoints. Thus, Hill's viewpoints may be philosophically novel, sui generis, still waiting to be validated and justified. PMID:24071010

  3. A Systematic Approach to Educational Needs Assessment.

    ERIC Educational Resources Information Center

    Florida Univ., Gainesville. Center for Community Needs Assessment.

    The focus of this paper is on the development of a model for assessing community educational needs, referred to as the Needs Assessment Project (NAP). The model's primary purpose is to classify, organize, and assign priority to community needs, so that the educational system can assign these needs to the proper administrative unit for changes to…

  4. Causal Comparative Analysis: Comprehensive Literacy Approach or the Traditional Reading Approach

    ERIC Educational Resources Information Center

    Fuda, Jessica Ann

    2009-01-01

    A comparative analysis study, examining the significance in reading achievement between students in the Comprehensive Literacy Program to students in the Traditional Basal Reading Approach was conducted. Implementation of the Comprehensive Literacy Program was an effort to lessen the achievement gap between proficient and low progressing students.…

  5. The Epstein–Glaser causal approach to the light-front QED{sub 4}. II: Vacuum polarization tensor

    SciTech Connect

    Bufalo, R.; Pimentel, B.M.; Soto, D.E.

    2014-12-15

    In this work we show how to construct the one-loop vacuum polarization for light-front QED{sub 4} in the framework of the perturbative causal theory. Usually, in the canonical approach, it is considered for the fermionic propagator the so-called instantaneous term, but it is known in the literature that this term is controversial because it can be omitted by computational reasons; for instance, by compensation or vanishing by dimensional regularization. In this work we propose a solution to this paradox. First, in the Epstein–Glaser causal theory, it is shown that the fermionic propagator does not have instantaneous term, and with this propagator we calculate the one-loop vacuum polarization, from this calculation it follows the same result as those obtained by the standard approach, but without reclaiming any extra assumptions. Moreover, since the perturbative causal theory is defined in the distributional framework, we can also show the reason behind our obtaining the same result whether we consider or not the instantaneous fermionic propagator term. - Highlights: • We develop the Epstein–Glaser causal approach for light-front field theory. • We evaluate in detail the vacuum polarization at one-loop for the light-front QED. • We discuss the subtle issues of the Instantaneous part of the fermionic propagator in the light-front. • We evaluate the vacuum polarization at one-loop for the light-front QED with the Instantaneous fermionic part.

  6. A Systematic Approach to Vocational Needs Assessment.

    ERIC Educational Resources Information Center

    Clawson, Thomas W.; Camp, Joseph J.

    This unit is designed to provide school psychologists with information helpful in consulting with teachers and counselors who have questions regarding the career and vocational needs of students. It is intended to help the school psychologist assist teachers and counselors to be effective in assessing the needs of students in their particular…

  7. The opportune time to invest in residential properties - Engle-Granger cointegration test and Granger causality test approach

    NASA Astrophysics Data System (ADS)

    Chee-Yin, Yip; Hock-Eam, Lim

    2014-12-01

    This paper examines using housing supply as proxy to house prices, the causal relationship on house prices among 8 states in Malaysia by applying the Engle-Granger cointegration test and Granger causality test approach. The target states are Perak, Selangor, Penang, Federal Territory of Kuala Lumpur (WPKL or Kuala Lumpur), Kedah, Negeri Sembilan, Sabah and Sarawak. The primary aim of this study is to estimate how long (in months) house prices in Perak lag behind that of Selangor, Penang and WPKL. We classify the 8 states into two categories - developed and developing states. We use Engle-Granger cointegration test and Granger causality test to examine the long run and short run equilibrium relationship among the two categories.. It is found that the causal relationship is bidirectional in Perak and Sabah, Perak and Selangor while it is unidirectional for Perak and Sarawak, Perak and Penang, Perak and WPKL. The speed of deviation adjustment is about 273%, suggesting that the pricing dynamic of Perak has a 32- month or 2 3/4- year lag behind that of WPKL, Selangor and Penang. Such information will be useful to investors, house buyers and speculators.

  8. Exploratory Causal Analysis in Bivariate Time Series Data

    NASA Astrophysics Data System (ADS)

    McCracken, James M.

    Many scientific disciplines rely on observational data of systems for which it is difficult (or impossible) to implement controlled experiments and data analysis techniques are required for identifying causal information and relationships directly from observational data. This need has lead to the development of many different time series causality approaches and tools including transfer entropy, convergent cross-mapping (CCM), and Granger causality statistics. In this thesis, the existing time series causality method of CCM is extended by introducing a new method called pairwise asymmetric inference (PAI). It is found that CCM may provide counter-intuitive causal inferences for simple dynamics with strong intuitive notions of causality, and the CCM causal inference can be a function of physical parameters that are seemingly unrelated to the existence of a driving relationship in the system. For example, a CCM causal inference might alternate between ''voltage drives current'' and ''current drives voltage'' as the frequency of the voltage signal is changed in a series circuit with a single resistor and inductor. PAI is introduced to address both of these limitations. Many of the current approaches in the times series causality literature are not computationally straightforward to apply, do not follow directly from assumptions of probabilistic causality, depend on assumed models for the time series generating process, or rely on embedding procedures. A new approach, called causal leaning, is introduced in this work to avoid these issues. The leaning is found to provide causal inferences that agree with intuition for both simple systems and more complicated empirical examples, including space weather data sets. The leaning may provide a clearer interpretation of the results than those from existing time series causality tools. A practicing analyst can explore the literature to find many proposals for identifying drivers and causal connections in times series data

  9. Energy planning for development - needs and approaches

    SciTech Connect

    Mubayi, V

    1981-01-01

    The capability of developing countries to carry out comprehensive national energy planning is examined. The analytical methods or models constructed for analyzing the energy system have to take into account the specific context in which they are built to address issues of interest to development planners. Issues discussed are resource development and technology research, energy equity considerations to all peoples in a nation, the pricing policy, and the balance of payments considerations. The impartance of the availability of adequate skilled personnel and training programs to impart the requisite skill necessary to carry out the planning is discussed. Various surveys were conducted to determine the training needs for energy planners in developing countries. (MCW)

  10. A Causal Modeling Approach to the Analysis of Course Evaluation Data.

    ERIC Educational Resources Information Center

    Wolfe, Mary L.

    Five causal models relating several aspects of end-of-term student evaluation of a graduate course in nursing research methods were proposed and tested empirically. The course evaluation form consisted of four Likert-type subscales, on which students rated the following aspects of the course: (1) the extent to which the course met its objectives;…

  11. A Bayesian network approach for causal inferences in pesticide risk assessment and management

    EPA Science Inventory

    Pesticide risk assessment and management must balance societal benefits and ecosystem protection, based on quantified risks and the strength of the causal linkages between uses of the pesticide and socioeconomic and ecological endpoints of concern. A Bayesian network (BN) is a gr...

  12. Grief among Surviving Family Members of Homicide Victims: A Causal Approach.

    ERIC Educational Resources Information Center

    Sprang, M. Virginia; And Others

    1993-01-01

    Proposed causal model to delineate predictors of self-reported grief among surviving family members of homicide victims. Evaluated model using data from survey of members of "Victims of Violence" support groups. Results generally supported model and indicated that correlates of grief differed across gender-specific subgroups in terms of their…

  13. Causal Discovery of Dynamic Systems

    ERIC Educational Resources Information Center

    Voortman, Mark

    2010-01-01

    Recently, several philosophical and computational approaches to causality have used an interventionist framework to clarify the concept of causality [Spirtes et al., 2000, Pearl, 2000, Woodward, 2005]. The characteristic feature of the interventionist approach is that causal models are potentially useful in predicting the effects of manipulations.…

  14. A Causal, Data-driven Approach to Modeling the Kepler Data

    NASA Astrophysics Data System (ADS)

    Wang, Dun; Hogg, David W.; Foreman-Mackey, Daniel; Schölkopf, Bernhard

    2016-09-01

    Astronomical observations are affected by several kinds of noise, each with its own causal source; there is photon noise, stochastic source variability, and residuals coming from imperfect calibration of the detector or telescope. The precision of NASA Kepler photometry for exoplanet science—the most precise photometric measurements of stars ever made—appears to be limited by unknown or untracked variations in spacecraft pointing and temperature, and unmodeled stellar variability. Here, we present the causal pixel model (CPM) for Kepler data, a data-driven model intended to capture variability but preserve transit signals. The CPM works at the pixel level so that it can capture very fine-grained information about the variation of the spacecraft. The CPM models the systematic effects in the time series of a pixel using the pixels of many other stars and the assumption that any shared signal in these causally disconnected light curves is caused by instrumental effects. In addition, we use the target star’s future and past (autoregression). By appropriately separating, for each data point, the data into training and test sets, we ensure that information about any transit will be perfectly isolated from the model. The method has four tuning parameters—the number of predictor stars or pixels, the autoregressive window size, and two L2-regularization amplitudes for model components, which we set by cross-validation. We determine values for tuning parameters that works well for most of the stars and apply the method to a corresponding set of target stars. We find that CPM can consistently produce low-noise light curves. In this paper, we demonstrate that pixel-level de-trending is possible while retaining transit signals, and we think that methods like CPM are generally applicable and might be useful for K2, TESS, etc., where the data are not clean postage stamps like Kepler.

  15. Causal Analysis After Haavelmo

    PubMed Central

    Heckman, James; Pinto, Rodrigo

    2014-01-01

    Haavelmo's seminal 1943 and 1944 papers are the first rigorous treatment of causality. In them, he distinguished the definition of causal parameters from their identification. He showed that causal parameters are defined using hypothetical models that assign variation to some of the inputs determining outcomes while holding all other inputs fixed. He thus formalized and made operational Marshall's (1890) ceteris paribus analysis. We embed Haavelmo's framework into the recursive framework of Directed Acyclic Graphs (DAGs) used in one influential recent approach to causality (Pearl, 2000) and in the related literature on Bayesian nets (Lauritzen, 1996). We compare the simplicity of an analysis of causality based on Haavelmo's methodology with the complex and nonintuitive approach used in the causal literature of DAGs—the “do-calculus” of Pearl (2009). We discuss the severe limitations of DAGs and in particular of the do-calculus of Pearl in securing identification of economic models. We extend our framework to consider models for simultaneous causality, a central contribution of Haavelmo. In general cases, DAGs cannot be used to analyze models for simultaneous causality, but Haavelmo's approach naturally generalizes to cover them. PMID:25729123

  16. The Epstein-Glaser causal approach to the light-front QED4. I: Free theory

    NASA Astrophysics Data System (ADS)

    Bufalo, R.; Pimentel, B. M.; Soto, D. E.

    2014-12-01

    In this work we present the study of light-front field theories in the realm of the axiomatic theory. It is known that when one uses the light-cone gauge pathological poles (k+) - n arises, demanding a prescription to be employed in order to tame these ill-defined poles and to have the correct Feynman integrals due to the lack of Wick rotation in such theories. In order to shed a new light on this long standing problem we present here a discussion based on the use of rigorous mathematical machinery of the distributional theory combined with physical concepts, such as causality, to show how to deal with these singular propagators in a general fashion without making use of any prescription. The first step of our development will consist in showing how the analytic representation for propagators arises by requiring general physical properties within the framework of Wightman's formalism. From that we shall determine the equal-time (anti)commutation relations in the light-front form for the scalar and fermionic fields, as well as for the dynamical components of the electromagnetic field. In conclusion, we introduce the Epstein-Glaser causal method in order to have a mathematical rigorous description of the free propagators of the theory, allowing us to discuss a general treatment for propagators of the type (k+) - n. Afterwards, we show that at given conditions our results reproduce known prescriptions in the literature.

  17. Multisource causal data mining

    NASA Astrophysics Data System (ADS)

    Woodley, Robert; Gosnell, Michael; Shallenberger, Kevin

    2012-06-01

    Analysts are faced with mountains of data, and finding that relevant piece of information is the proverbial needle in a haystack, only with dozens of haystacks. Analysis tools that facilitate identifying causal relationships across multiple data sets are sorely needed. 21st Century Systems, Inc. (21CSi) has initiated research called Causal-View, a causal datamining visualization tool, to address this challenge. Causal-View is built on an agent-enabled framework. Much of the processing that Causal-View will do is in the background. When a user requests information, Data Extraction Agents launch to gather information. This initial search is a raw, Monte Carlo type search designed to gather everything available that may have relevance to an individual, location, associations, and more. This data is then processed by Data- Mining Agents. The Data-Mining Agents are driven by user supplied feature parameters. If the analyst is looking to see if the individual frequents a known haven for insurgents he may request information on his last known locations. Or, if the analyst is trying to see if there is a pattern in the individual's contacts, the mining agent can be instructed with the type and relevance of the information fields to look at. The same data is extracted from the database, but the Data Mining Agents customize the feature set to determine causal relationships the user is interested in. At this point, a Hypothesis Generation and Data Reasoning Agents take over to form conditional hypotheses about the data and pare the data, respectively. The newly formed information is then published to the agent communication backbone of Causal- View to be displayed. Causal-View provides causal analysis tools to fill the gaps in the causal chain. We present here the Causal-View concept, the initial research into data mining tools that assist in forming the causal relationships, and our initial findings.

  18. A new life-span approach to conscientiousness and health: combining the pieces of the causal puzzle.

    PubMed

    Friedman, Howard S; Kern, Margaret L; Hampson, Sarah E; Duckworth, Angela Lee

    2014-05-01

    Conscientiousness has been shown to predict healthy behaviors, healthy social relationships, and physical health and longevity. The causal links, however, are complex and not well elaborated. Many extant studies have used comparable measures for conscientiousness, and a systematic endeavor to build cross-study analyses for conscientiousness and health now seems feasible. Of particular interest are efforts to construct new, more comprehensive causal models by linking findings and combining data from existing studies of different cohorts. Although methodological perils can threaten such integration, such efforts offer an early opportunity to enliven a life course perspective on conscientiousness, to see whether component facets of conscientiousness remain related to each other and to relevant mediators across broad spans of time, and to bolster the findings of the few long-term longitudinal studies of the dynamics of personality and health. A promising approach to testing new models involves pooling data from extant studies as an efficient and heuristic prelude to large-scale testing of interventions. PMID:23088747

  19. Relativistic causal hydrodynamics derived from Boltzmann equation: A novel reduction theoretical approach

    NASA Astrophysics Data System (ADS)

    Tsumura, Kyosuke; Kikuchi, Yuta; Kunihiro, Teiji

    2015-10-01

    We derive the second-order hydrodynamic equation and the microscopic formulas of the relaxation times as well as the transport coefficients systematically from the relativistic Boltzmann equation. Our derivation is based on a novel development of the renormalization-group method, a powerful reduction theory of dynamical systems, which has been applied successfully to derive the nonrelativistic second-order hydrodynamic equation. Our theory nicely gives a compact expression of the deviation of the distribution function in terms of the linearized collision operator, which is different from those used as an ansatz in the conventional fourteen-moment method. It is confirmed that the resultant microscopic expressions of the transport coefficients coincide with those derived in the Chapman-Enskog expansion method. Furthermore, we show that the microscopic expressions of the relaxation times have natural and physically plausible forms. We prove that the propagating velocities of the fluctuations of the hydrodynamical variables do not exceed the light velocity, and hence our second-order equation ensures the desired causality. It is also confirmed that the equilibrium state is stable for any perturbation described by our equation.

  20. Localization of causal locus in the genome of the brown macroalga Ectocarpus: NGS-based mapping and positional cloning approaches.

    PubMed

    Billoud, Bernard; Jouanno, Émilie; Nehr, Zofia; Carton, Baptiste; Rolland, Élodie; Chenivesse, Sabine; Charrier, Bénédicte

    2015-01-01

    Mutagenesis is the only process by which unpredicted biological gene function can be identified. Despite that several macroalgal developmental mutants have been generated, their causal mutation was never identified, because experimental conditions were not gathered at that time. Today, progresses in macroalgal genomics and judicious choices of suitable genetic models make mutated gene identification possible. This article presents a comparative study of two methods aiming at identifying a genetic locus in the brown alga Ectocarpus siliculosus: positional cloning and Next-Generation Sequencing (NGS)-based mapping. Once necessary preliminary experimental tools were gathered, we tested both analyses on an Ectocarpus morphogenetic mutant. We show how a narrower localization results from the combination of the two methods. Advantages and drawbacks of these two approaches as well as potential transfer to other macroalgae are discussed. PMID:25745426

  1. Localization of causal locus in the genome of the brown macroalga Ectocarpus: NGS-based mapping and positional cloning approaches

    PubMed Central

    Billoud, Bernard; Jouanno, Émilie; Nehr, Zofia; Carton, Baptiste; Rolland, Élodie; Chenivesse, Sabine; Charrier, Bénédicte

    2015-01-01

    Mutagenesis is the only process by which unpredicted biological gene function can be identified. Despite that several macroalgal developmental mutants have been generated, their causal mutation was never identified, because experimental conditions were not gathered at that time. Today, progresses in macroalgal genomics and judicious choices of suitable genetic models make mutated gene identification possible. This article presents a comparative study of two methods aiming at identifying a genetic locus in the brown alga Ectocarpus siliculosus: positional cloning and Next-Generation Sequencing (NGS)-based mapping. Once necessary preliminary experimental tools were gathered, we tested both analyses on an Ectocarpus morphogenetic mutant. We show how a narrower localization results from the combination of the two methods. Advantages and drawbacks of these two approaches as well as potential transfer to other macroalgae are discussed. PMID:25745426

  2. The Epstein–Glaser causal approach to the light-front QED{sub 4}. I: Free theory

    SciTech Connect

    Bufalo, R. Pimentel, B.M. Soto, D.E.

    2014-12-15

    In this work we present the study of light-front field theories in the realm of the axiomatic theory. It is known that when one uses the light-cone gauge pathological poles (k{sup +}){sup −n} arises, demanding a prescription to be employed in order to tame these ill-defined poles and to have the correct Feynman integrals due to the lack of Wick rotation in such theories. In order to shed a new light on this long standing problem we present here a discussion based on the use of rigorous mathematical machinery of the distributional theory combined with physical concepts, such as causality, to show how to deal with these singular propagators in a general fashion without making use of any prescription. The first step of our development will consist in showing how the analytic representation for propagators arises by requiring general physical properties within the framework of Wightman’s formalism. From that we shall determine the equal-time (anti)commutation relations in the light-front form for the scalar and fermionic fields, as well as for the dynamical components of the electromagnetic field. In conclusion, we introduce the Epstein–Glaser causal method in order to have a mathematical rigorous description of the free propagators of the theory, allowing us to discuss a general treatment for propagators of the type (k{sup +}){sup −n}. Afterwards, we show that at given conditions our results reproduce known prescriptions in the literature. - Highlights: • We develop the analytic representation for propagators in Wightman’s framework. • We make use of the analytic representation to obtain equal-time (anti)commutation relations in the light-front. • We derive the free Feynman propagators for the light-front quantum electrodynamics in the Epstein–Glaser approach. • We determine a general expression for the propagator associated to the light-cone poles (k{sup +}){sup −n} in the causal approach.

  3. Combining GWAS and RNA-Seq Approaches for Detection of the Causal Mutation for Hereditary Junctional Epidermolysis Bullosa in Sheep.

    PubMed

    Suárez-Vega, Aroa; Gutiérrez-Gil, Beatriz; Benavides, Julio; Perez, Valentín; Tosser-Klopp, Gwenola; Klopp, Christophe; Keennel, Stephen J; Arranz, Juan José

    2015-01-01

    In this study, we demonstrate the use of a genome-wide association mapping together with RNA-seq in a reduced number of samples, as an efficient approach to detect the causal mutation for a Mendelian disease. Junctional epidermolysis bullosa is a recessive genodermatosis that manifests with neonatal mechanical fragility of the skin, blistering confined to the lamina lucida of the basement membrane and severe alteration of the hemidesmosomal junctions. In Spanish Churra sheep, junctional epidermolysis bullosa (JEB) has been detected in two commercial flocks. The JEB locus was mapped to Ovis aries chromosome 11 by GWAS and subsequently fine-mapped to an 868-kb homozygous segment using the identical-by-descent method. The ITGB4, which is located within this region, was identified as the best positional and functional candidate gene. The RNA-seq variant analysis enabled us to discover a 4-bp deletion within exon 33 of the ITGB4 gene (c.4412_4415del). The c.4412_4415del mutation causes a frameshift resulting in a premature stop codon at position 1472 of the integrin β4 protein. A functional analysis of this deletion revealed decreased levels of mRNA in JEB skin samples and the absence of integrin β4 labeling in immunohistochemical assays. Genotyping of c.4412_4415del showed perfect concordance with the recessive mode of the disease phenotype. Selection against this causal mutation will now be used to solve the problem of JEB in flocks of Churra sheep. Furthermore, the identification of the ITGB4 mutation means that affected sheep can be used as a large mammal animal model for the human form of epidermolysis bullosa with aplasia cutis. Our approach evidences that RNA-seq offers cost-effective alternative to identify variants in the species in which high resolution exome-sequencing is not straightforward. PMID:25955497

  4. Combining GWAS and RNA-Seq Approaches for Detection of the Causal Mutation for Hereditary Junctional Epidermolysis Bullosa in Sheep

    PubMed Central

    Suárez-Vega, Aroa; Gutiérrez-Gil, Beatriz; Benavides, Julio; Perez, Valentín; Tosser-Klopp, Gwenola; Klopp, Christophe; Keennel, Stephen J.; Arranz, Juan José

    2015-01-01

    In this study, we demonstrate the use of a genome-wide association mapping together with RNA-seq in a reduced number of samples, as an efficient approach to detect the causal mutation for a Mendelian disease. Junctional epidermolysis bullosa is a recessive genodermatosis that manifests with neonatal mechanical fragility of the skin, blistering confined to the lamina lucida of the basement membrane and severe alteration of the hemidesmosomal junctions. In Spanish Churra sheep, junctional epidermolysis bullosa (JEB) has been detected in two commercial flocks. The JEB locus was mapped to Ovis aries chromosome 11 by GWAS and subsequently fine-mapped to an 868-kb homozygous segment using the identical-by-descent method. The ITGB4, which is located within this region, was identified as the best positional and functional candidate gene. The RNA-seq variant analysis enabled us to discover a 4-bp deletion within exon 33 of the ITGB4 gene (c.4412_4415del). The c.4412_4415del mutation causes a frameshift resulting in a premature stop codon at position 1472 of the integrin β4 protein. A functional analysis of this deletion revealed decreased levels of mRNA in JEB skin samples and the absence of integrin β4 labeling in immunohistochemical assays. Genotyping of c.4412_4415del showed perfect concordance with the recessive mode of the disease phenotype. Selection against this causal mutation will now be used to solve the problem of JEB in flocks of Churra sheep. Furthermore, the identification of the ITGB4 mutation means that affected sheep can be used as a large mammal animal model for the human form of epidermolysis bullosa with aplasia cutis. Our approach evidences that RNA-seq offers cost-effective alternative to identify variants in the species in which high resolution exome-sequencing is not straightforward. PMID:25955497

  5. Need for multiple approaches in collaborative software development.

    SciTech Connect

    LePoire, D. J.

    2002-02-26

    The need to share software and reintegrate it into new applications presents a difficult but important challenge. Component-based development as an approach to this problem is receiving much attention in professional journals and academic curricula. However, there are many other approaches to collaborative software development that might be more appropriate. This paper reviews a few of these approaches and discusses criteria for the conditions and contexts in which these alternative approaches might be more appropriate. This paper complements the discussion of context-based development team organizations and processes. Examples from a small development team that interacts with a larger professional community are analyzed.

  6. Optimal causal inference: Estimating stored information and approximating causal architecture

    NASA Astrophysics Data System (ADS)

    Still, Susanne; Crutchfield, James P.; Ellison, Christopher J.

    2010-09-01

    We introduce an approach to inferring the causal architecture of stochastic dynamical systems that extends rate-distortion theory to use causal shielding—a natural principle of learning. We study two distinct cases of causal inference: optimal causal filtering and optimal causal estimation. Filtering corresponds to the ideal case in which the probability distribution of measurement sequences is known, giving a principled method to approximate a system's causal structure at a desired level of representation. We show that in the limit in which a model-complexity constraint is relaxed, filtering finds the exact causal architecture of a stochastic dynamical system, known as the causal-state partition. From this, one can estimate the amount of historical information the process stores. More generally, causal filtering finds a graded model-complexity hierarchy of approximations to the causal architecture. Abrupt changes in the hierarchy, as a function of approximation, capture distinct scales of structural organization. For nonideal cases with finite data, we show how the correct number of the underlying causal states can be found by optimal causal estimation. A previously derived model-complexity control term allows us to correct for the effect of statistical fluctuations in probability estimates and thereby avoid overfitting.

  7. Causality and headache triggers

    PubMed Central

    Turner, Dana P.; Smitherman, Todd A.; Martin, Vincent T.; Penzien, Donald B.; Houle, Timothy T.

    2013-01-01

    Objective The objective of this study was to explore the conditions necessary to assign causal status to headache triggers. Background The term “headache trigger” is commonly used to label any stimulus that is assumed to cause headaches. However, the assumptions required for determining if a given stimulus in fact has a causal-type relationship in eliciting headaches have not been explicated. Methods A synthesis and application of Rubin’s Causal Model is applied to the context of headache causes. From this application the conditions necessary to infer that one event (trigger) causes another (headache) are outlined using basic assumptions and examples from relevant literature. Results Although many conditions must be satisfied for a causal attribution, three basic assumptions are identified for determining causality in headache triggers: 1) constancy of the sufferer; 2) constancy of the trigger effect; and 3) constancy of the trigger presentation. A valid evaluation of a potential trigger’s effect can only be undertaken once these three basic assumptions are satisfied during formal or informal studies of headache triggers. Conclusions Evaluating these assumptions is extremely difficult or infeasible in clinical practice, and satisfying them during natural experimentation is unlikely. Researchers, practitioners, and headache sufferers are encouraged to avoid natural experimentation to determine the causal effects of headache triggers. Instead, formal experimental designs or retrospective diary studies using advanced statistical modeling techniques provide the best approaches to satisfy the required assumptions and inform causal statements about headache triggers. PMID:23534872

  8. Taking Emergence Seriously: The Centrality of Circular Causality for Dynamic Systems Approaches to Development

    ERIC Educational Resources Information Center

    Witherington, David C.

    2011-01-01

    The dynamic systems (DS) approach has emerged as an influential and potentially unifying metatheory for developmental science. Its central platform--the argument against design--suggests that structure spontaneously and without prescription emerges through self-organization. In one of the most prominent accounts of DS, Thelen and her colleagues…

  9. An Ecological Approach to Needs Assessment For Inservice Training.

    ERIC Educational Resources Information Center

    Sherrill, Claudine

    Physical educators must explore the interrelationships between persons and their total human environment to promote optimal learning. This form of needs assessment broadens the concept of teaching from a student- and school-based perspective to one encompassing the home and community. This ecological approach is more crucial in facilitating…

  10. A systematic approach to training: A training needs assessment

    NASA Technical Reports Server (NTRS)

    Manning, Margaret H.

    1989-01-01

    In an effort to determine the gap between the actual performance and the necessary performance of employees for the effective and efficient accomplishment of an organization's mission and goals, an organization-wide Training Needs Assessment must be conducted. The purpose of this work was to conduct a training needs analysis and prepare a NASA Langley Catalog of On-Site Training programs. The work included developing a Training Needs Assessment Survey, implementing the survey, analyzing and researching the training needs, identifying the courses to meet the needs, and preparing and designing an On-Site Training Catalog. This needs analysis attempted to identify performance weaknesses and deficits; seek out and provide opportunities for improved performance; anticipate and avoid future problems; enhance and create new strengths. The end product is a user-friendly catalog of on-site training available. The results include: top-down approach to needs assessment; improved communication with training coordinators; 98 percent return rate of the Training Needs Assessment survey; complete, newly designed, user-friendly catalog; 167 catalog descriptions advertised; 82 new courses advertised; training logo; and request for the training application form.

  11. Approaches for prioritising the nutritional needs of refugee communities.

    PubMed

    Palermo, Claire; Robinson, Clare; Robertson, Kate; Hii, Shireen

    2012-01-01

    An important part of health promotion planning is identifying priority areas for programs. A typical approach includes a needs assessment where a deficit-oriented approach captures problems within a community. Approaches that focus on strengths have emerged as potentially more appropriate and effective methods for program planning. This report describes the outcomes and learning from using both a deficit-oriented and strength-based approach for identifying and describing nutrition priorities of refugee communities. Focus groups (n=11) were conducted using both methods with a total of 69 community members from Afghan, Burmese and Sudanese backgrounds. Analysis of the focus group transcripts using a content analysis approach identified key influences on food choice and determinants of health and nutrition. There were differences in the type of information obtained from the deficit-oriented and strength-based approach. Although the strength-based approach was unfamiliar to participants and offered several challenges, it identified unique aspects of the communities that were not identified by the deficit-oriented approach, and could be used as the basis for planning community health promotion strategies. Elements of each method should be considered when designing community program planning strategies. PMID:22394657

  12. Relativistic causality

    NASA Astrophysics Data System (ADS)

    Valente, Giovanni; Owen Weatherall, James

    2014-11-01

    Relativity theory is often taken to include, or to imply, a prohibition on superluminal propagation of causal processes. Yet, what exactly the prohibition on superluminal propagation amounts to and how one should deal with its possible violation have remained open philosophical problems, both in the context of the metaphysics of causation and the foundations of physics. In particular, recent work in philosophy of physics has focused on the causal structure of spacetime in relativity theory and on how this causal structure manifests itself in our most fundamental theories of matter. These topics were the subject of a workshop on "Relativistic Causality in Quantum Field Theory and General Relativity" that we organized (along with John Earman) at the Center for Philosophy of Science in Pittsburgh on April 5-7, 2013. The present Special Issue comprises contributions by speakers in that workshop as well as several other experts exploring different aspects of relativistic causality. We are grateful to the journal for hosting this Special Issue, to the journal's managing editor, Femke Kuiling, for her help and support in putting the issue together, and to the authors and the referees for their excellent work.

  13. Abnormal causal attribution leads to advantageous economic decision-making: A neuropsychological approach

    PubMed Central

    Koscik, Timothy R.; Tranel, Daniel

    2013-01-01

    People tend to assume that outcomes are caused by dispositional factors, e.g., a person’s constitution or personality, even when the actual cause is due to situational factors, e.g., luck or coincidence. This is known as the ‘correspondence bias.’ This tendency can lead normal, intelligent persons to make suboptimal decisions. Here, we used a neuropsychological approach to investigate the neural basis of the correspondence bias, by studying economic decision-making in patients with damage to the ventromedial prefrontal cortex (vmPFC). Given the role of the vmPFC in social cognition, we predicted that vmPFC is necessary for the normal correspondence bias. In our experiment, consistent with expectations, healthy (N=46) and brain-damaged (N=30) comparison participants displayed the correspondence bias when investing and invested no differently when given dispositional or situational information. By contrast, vmPFC patients (N=17) displayed a lack of correspondence bias and invested more when given dispositional than situational information. The results support the conclusion that vmPFC is critical for normal social inference and the correspondence bias, and our findings help clarify the important (and potentially disadvantageous) role of social inference in economic decision-making. PMID:23574584

  14. Translational research-the need of a new bioethics approach.

    PubMed

    Hostiuc, Sorin; Moldoveanu, Alin; Dascălu, Maria-Iuliana; Unnthorsson, Runar; Jóhannesson, Ómar I; Marcus, Ioan

    2016-01-01

    Translational research tries to apply findings from basic science to enhance human health and well-being. Many phases of the translational research may include non-medical tasks (information technology, engineering, nanotechnology, biochemistry, animal research, economy, sociology, psychology, politics, and so on). Using common bioethics principles to these areas might sometimes be not feasible, or even impossible. However, the whole process must respect some fundamental, moral principles. The purpose of this paper is to argument the need for a different approach to the morality in translational bioethics, and to suggest some directions that might be followed when constructing such a bioethics. We will show that a new approach is needed and present a few ethical issues that are specific to the translational research. PMID:26767499

  15. Redundant variables and Granger causality

    NASA Astrophysics Data System (ADS)

    Angelini, L.; de Tommaso, M.; Marinazzo, D.; Nitti, L.; Pellicoro, M.; Stramaglia, S.

    2010-03-01

    We discuss the use of multivariate Granger causality in presence of redundant variables: the application of the standard analysis, in this case, leads to under estimation of causalities. Using the un-normalized version of the causality index, we quantitatively develop the notions of redundancy and synergy in the frame of causality and propose two approaches to group redundant variables: (i) for a given target, the remaining variables are grouped so as to maximize the total causality and (ii) the whole set of variables is partitioned to maximize the sum of the causalities between subsets. We show the application to a real neurological experiment, aiming to a deeper understanding of the physiological basis of abnormal neuronal oscillations in the migraine brain. The outcome by our approach reveals the change in the informational pattern due to repetitive transcranial magnetic stimulations.

  16. Causal inference based on counterfactuals

    PubMed Central

    Höfler, M

    2005-01-01

    Background The counterfactual or potential outcome model has become increasingly standard for causal inference in epidemiological and medical studies. Discussion This paper provides an overview on the counterfactual and related approaches. A variety of conceptual as well as practical issues when estimating causal effects are reviewed. These include causal interactions, imperfect experiments, adjustment for confounding, time-varying exposures, competing risks and the probability of causation. It is argued that the counterfactual model of causal effects captures the main aspects of causality in health sciences and relates to many statistical procedures. Summary Counterfactuals are the basis of causal inference in medicine and epidemiology. Nevertheless, the estimation of counterfactual differences pose several difficulties, primarily in observational studies. These problems, however, reflect fundamental barriers only when learning from observations, and this does not invalidate the counterfactual concept. PMID:16159397

  17. Ecosystem approach to inland fisheries: research needs and implementation strategies

    PubMed Central

    Beard, T. Douglas; Arlinghaus, Robert; Cooke, Steven J.; McIntyre, Peter B.; De Silva, Sena; Bartley, Devin; Cowx, Ian G.

    2011-01-01

    Inland fisheries are a vital component in the livelihoods and food security of people throughout the world, as well as contributing huge recreational and economic benefits. These valuable assets are jeopardized by lack of research-based understanding of the impacts of fisheries on inland ecosystems, and similarly the impact of human activities associated with inland waters on fisheries and aquatic biodiversity. To explore this topic, an international workshop was organized in order to examine strategies to incorporate fisheries into ecosystem approaches for management of inland waters. To achieve this goal, a new research agenda is needed that focuses on: quantifying the ecosystem services provided by fresh waters; quantifying the economic, social and nutritional benefits of inland fisheries; improving assessments designed to evaluate fisheries exploitation potential; and examining feedbacks between fisheries, ecosystem productivity and aquatic biodiversity. Accomplishing these objectives will require merging natural and social science approaches to address coupled social–ecological system dynamics. PMID:21325307

  18. Ecosystem approach to inland fisheries: research needs and implementation strategies

    USGS Publications Warehouse

    Beard, T. Douglas, Jr.; Arlinghaus, Robert; Cooke, Steven J.; McIntyre, Peter B.; De Silva, Sena; Bartley, Devin M.; Cowx, Ian G.

    2011-01-01

    Inland fisheries are a vital component in the livelihoods and food security of people throughout the world, as well as contributing huge recreational and economic benefits. These valuable assets are jeopardized by lack of research-based understanding of the impacts of fisheries on inland ecosystems, and similarly the impact of human activities associated with inland waters on fisheries and aquatic biodiversity. To explore this topic, an international workshop was organized in order to examine strategies to incorporate fisheries into ecosystem approaches for management of inland waters. To achieve this goal, a new research agenda is needed that focuses on: quantifying the ecosystem services provided by fresh waters; quantifying the economic, social and nutritional benefits of inland fisheries; improving assessments designed to evaluate fisheries exploitation potential; and examining feedbacks between fisheries, ecosystem productivity and aquatic biodiversity. Accomplishing these objectives will require merging natural and social science approaches to address coupled social–ecological system dynamics.

  19. Ecosystem approach to inland fisheries: Research needs and implementation strategies

    USGS Publications Warehouse

    Beard, T.D., Jr.; Arlinghaus, R.; Cooke, S.J.; McIntyre, P.B.; De Silva, S.; Bartley, D.; Cowx, I.G.

    2011-01-01

    Inland fisheries are a vital component in the livelihoods and food security of people throughout the world, as well as contributing huge recreational and economic benefits. These valuable assets are jeopardized by lack of research-based understanding of the impacts of fisheries on inland ecosystems, and similarly the impact of human activities associated with inland waters on fisheries and aquatic biodiversity. To explore this topic, an international workshop was organized in order to examine strategies to incorporate fisheries into ecosystem approaches for management of inland waters. To achieve this goal, a new research agenda is needed that focuses on: quantifying the ecosystem services provided by fresh waters; quantifying the economic, social and nutritional benefits of inland fisheries; improving assessments designed to evaluate fisheries exploitation potential; and examining feedbacks between fisheries, ecosystem productivity and aquatic biodiversity. Accomplishing these objectives will require merging natural and social science approaches to address coupled social-ecological system dynamics. ?? 2010 The Royal Society.

  20. Causality assessment: A brief insight into practices in pharmaceutical industry.

    PubMed

    Naidu, R Purushotham

    2013-10-01

    Healthcare industry is flooded with multitude of drugs, and the list is increasing day by day. Consumption of medications has enormously increased due to life style changes, having safer drugs is the need of the hour. Regulators and other authorities to have a check have put in stringent regulations and pharmacovigilance system in place. Eventhough there has been increase in adverse drug reactions (ADR) reporting in the last decade, causality assessment has been the greater challenge for academicians and even industry. Causality is crucial for risk benefit assessment, particularly when it involves post marketing safety signals. Pharmaceutical companies have put in efforts to have a standardized approach for causality assessment. This article will provide some insight into the approaches for causality assessment from a pharma industry perspective. PMID:24312892

  1. Identification of causal genes for complex traits

    PubMed Central

    Hormozdiari, Farhad; Kichaev, Gleb; Yang, Wen-Yun; Pasaniuc, Bogdan; Eskin, Eleazar

    2015-01-01

    Motivation: Although genome-wide association studies (GWAS) have identified thousands of variants associated with common diseases and complex traits, only a handful of these variants are validated to be causal. We consider ‘causal variants’ as variants which are responsible for the association signal at a locus. As opposed to association studies that benefit from linkage disequilibrium (LD), the main challenge in identifying causal variants at associated loci lies in distinguishing among the many closely correlated variants due to LD. This is particularly important for model organisms such as inbred mice, where LD extends much further than in human populations, resulting in large stretches of the genome with significantly associated variants. Furthermore, these model organisms are highly structured and require correction for population structure to remove potential spurious associations. Results: In this work, we propose CAVIAR-Gene (CAusal Variants Identification in Associated Regions), a novel method that is able to operate across large LD regions of the genome while also correcting for population structure. A key feature of our approach is that it provides as output a minimally sized set of genes that captures the genes which harbor causal variants with probability ρ. Through extensive simulations, we demonstrate that our method not only speeds up computation, but also have an average of 10% higher recall rate compared with the existing approaches. We validate our method using a real mouse high-density lipoprotein data (HDL) and show that CAVIAR-Gene is able to identify Apoa2 (a gene known to harbor causal variants for HDL), while reducing the number of genes that need to be tested for functionality by a factor of 2. Availability and implementation: Software is freely available for download at genetics.cs.ucla.edu/caviar. Contact: eeskin@cs.ucla.edu PMID:26072484

  2. The role of need for closure in essentialist entitativity beliefs and prejudice: an epistemic needs approach to racial categorization.

    PubMed

    Roets, Arne; Van Hiel, Alain

    2011-03-01

    The present research investigates how people's general epistemic motives may inspire essentialist beliefs about racial groups and racism. In three studies, we focus particularly on essentialist entitativity (EE, referring to beliefs about the uniformity, informativeness, and inherent core of racial groups), probing into its relationships with epistemic need for closure (NFC) and prejudice. In Study 1, we develop an EE scale, empirically distinguish it from the naturalness component of essentialism and non-EE beliefs, and establish its predictive utility for explaining racial prejudice. Study 2 provides experimental evidence for the causal effect of NFC on EE beliefs. Study 3 demonstrates in three different samples that EE beliefs mediate the relationship between dispositional NFC and racial prejudice. It is argued that EE beliefs about racial groups are an expression of motivated social cognition, serving people's seizing needs for quick and easy social judgment. PMID:21366612

  3. Designing sustainable work systems: the need for a systems approach.

    PubMed

    Zink, Klaus J

    2014-01-01

    There is a growing discussion concerning sustainability. While this discussion was at first mainly focused on a society level--and sometimes regarding especially environmental problems, one can now see that this topic is of increasing relevance for companies worldwide and even the social dimension of this three pillar approach is gaining more and more importance. This leads to some questions: Is sustainability already a part of human factors thinking or do we have to further develop our discipline? How can we define sustainable work systems? What are the topics we have to consider? Do we need a new systems ergonomics perspective regarding whole value creation chains and a life-cycle perspective concerning products (and work systems)? How can we deal with potential contradictions about social, ecological, and economic goals? PMID:23608710

  4. A New Life-Span Approach to Conscientiousness and Health: Combining the Pieces of the Causal Puzzle

    ERIC Educational Resources Information Center

    Friedman, Howard S.; Kern, Margaret L.; Hampson, Sarah E.; Duckworth, Angela Lee

    2014-01-01

    Conscientiousness has been shown to predict healthy behaviors, healthy social relationships, and physical health and longevity. The causal links, however, are complex and not well elaborated. Many extant studies have used comparable measures for conscientiousness, and a systematic endeavor to build cross-study analyses for conscientiousness and…

  5. The Well-Being of Children Born to Teen Mothers: Multiple Approaches to Assessing the Causal Links. JCPR Working Paper.

    ERIC Educational Resources Information Center

    Levine, Judith A.; Pollack, Harold

    This study used linked maternal-child data from the 1997-1998 National Longitudinal Survey of Youth to explore the wellbeing of children born to teenage mothers. Two econometric techniques explored the causal impact of early childbearing on subsequent child and adolescent outcomes. First, a fixed-effect, cousin-comparison analysis controlled for…

  6. Environmental impact assessment: National approaches and international needs.

    PubMed

    Burton, I; Wilson, J; Munn, R E

    1983-06-01

    This paper examines the spread and development of 'environmental impact assessment' (EIA) since the enactment of the U.S. Environmental Policy Act on January 1, 1970, which established for the first time under any jurisdiction the formal requirement that an EIA be made and that an 'environmental impact statement' (EIS) be filed prior to implementation of certain major development projects.The paper is divided into three parts. In the first part, we briefly review the forms of EIA introduced in the western industrial countries and contrast these with developments in the socialist countries of Eastern Europe, and in the Third World. The approaches to EIA adopted by five countries - the United States, Australia, Canada, the Federal Republic of Germany, and the Soviet Union - are used to illustrate the types of national approaches that have been followed. In the second part of the paper, we use some questions raised by impact assessments as codified in legislation or regulations at the national level to highlight some of the limitations of impact assessment. Finally, we turn to international impact assessments and describe the modest progress made to date. Key impediments to the development of appropriate conceptual and institutional frameworks and methodologies for international EIAs are noted.In conclusion, we offer some suggestions about needed actions at both the national and international levels. PMID:24258931

  7. Exploring the relationship between child physical abuse and adult dating violence using a causal inference approach in an emerging adult population in South Korea.

    PubMed

    Jennings, Wesley G; Park, MiRang; Richards, Tara N; Tomsich, Elizabeth; Gover, Angela; Powers, Ráchael A

    2014-12-01

    Child maltreatment is one of the most commonly examined risk factors for violence in dating relationships. Often referred to as the intergenerational transmission of violence or cycle of violence, a fair amount of research suggests that experiencing abuse during childhood significantly increases the likelihood of involvement in violent relationships later, but these conclusions are primarily based on correlational research designs. Furthermore, the majority of research linking childhood maltreatment and dating violence has focused on samples of young people from the United States. Considering these limitations, the current study uses a rigorous, propensity score matching approach to estimate the causal effect of experiencing child physical abuse on adult dating violence among a large sample of South Korean emerging adults. Results indicate that the link between child physical abuse and adult dating violence is spurious rather than causal. Study limitations and implications are discussed. PMID:25220481

  8. Integrated approaches to climate-crop modelling: needs and challenges.

    PubMed

    Betts, Richard A

    2005-11-29

    This paper discusses the need for a more integrated approach to modelling changes in climate and crops, and some of the challenges posed by this. While changes in atmospheric composition are expected to exert an increasing radiative forcing of climate change leading to further warming of global mean temperatures and shifts in precipitation patterns, these are not the only climatic processes which may influence crop production. Changes in the physical characteristics of the land cover may also affect climate; these may arise directly from land use activities and may also result from the large-scale responses of crops to seasonal, interannual and decadal changes in the atmospheric state. Climate models used to drive crop models may, therefore, need to consider changes in the land surface, either as imposed boundary conditions or as feedbacks from an interactive climate-vegetation model. Crops may also respond directly to changes in atmospheric composition, such as the concentrations of carbon dioxide (CO2), ozone (03) and compounds of sulphur and nitrogen, so crop models should consider these processes as well as climate change. Changes in these, and the responses of the crops, may be intimately linked with meteorological processes so crop and climate models should consider synergies between climate and atmospheric chemistry. Some crop responses may occur at scales too small to significantly influence meteorology, so may not need to be included as feedbacks within climate models. However, the volume of data required to drive the appropriate crop models may be very large, especially if short-time-scale variability is important. Implementation of crop models within climate models would minimize the need to transfer large quantities of data between separate modelling systems. It should also be noted that crop responses to climate change may interact with other impacts of climate change, such as hydrological changes. For example, the availability of water for irrigation

  9. Integrated approaches to climate–crop modelling: needs and challenges

    PubMed Central

    A. Betts, Richard

    2005-01-01

    This paper discusses the need for a more integrated approach to modelling changes in climate and crops, and some of the challenges posed by this. While changes in atmospheric composition are expected to exert an increasing radiative forcing of climate change leading to further warming of global mean temperatures and shifts in precipitation patterns, these are not the only climatic processes which may influence crop production. Changes in the physical characteristics of the land cover may also affect climate; these may arise directly from land use activities and may also result from the large-scale responses of crops to seasonal, interannual and decadal changes in the atmospheric state. Climate models used to drive crop models may, therefore, need to consider changes in the land surface, either as imposed boundary conditions or as feedbacks from an interactive climate–vegetation model. Crops may also respond directly to changes in atmospheric composition, such as the concentrations of carbon dioxide (CO2), ozone (O3) and compounds of sulphur and nitrogen, so crop models should consider these processes as well as climate change. Changes in these, and the responses of the crops, may be intimately linked with meteorological processes so crop and climate models should consider synergies between climate and atmospheric chemistry. Some crop responses may occur at scales too small to significantly influence meteorology, so may not need to be included as feedbacks within climate models. However, the volume of data required to drive the appropriate crop models may be very large, especially if short-time-scale variability is important. Implementation of crop models within climate models would minimize the need to transfer large quantities of data between separate modelling systems. It should also be noted that crop responses to climate change may interact with other impacts of climate change, such as hydrological changes. For example, the availability of water for

  10. A regional approach to unmet needs in anaphylaxis.

    PubMed

    Minale, P; Bignardi, D; Troise, C; Voltolini, S; Dignetti, P

    2016-05-01

    Allergic diseases are under-diagnosed and undertreated despite their wide prevalence, and particularly anaphylaxis is often under-estimated. Evidence-based anaphylaxis guidelines developed by principal allergy organizations agree on increased prevalence of anaphylaxis, especially in patients younger than 18 years (18-27,30): this trend highlights the need for actions on anaphylaxis management and prevention (3,4). Lack of prompt connection between emergency department and allergy unit after discharge, and of a dedicated ICD-9th identification code (18-26), can delay diagnosis and treatment of anaphylaxis (28,29). Also in the experience of our Allergy Unit, patients reach the allergist office after several attacks treated in ED (17), without a previous evaluation and risk assessment. Keeping in mind unmet needs in anaphylaxis (4), we focused on regional approaches to health care delivery. The key point of our project was to establish an active collaboration between allergist clinicians and their counterparts in emergency medicine, with a system of quick filing report of patients discharged from ED with the suspect of anaphylactic reaction, directed to a central allergy unit, acting in a hub and spoke model with the Ligurian allergy network (31). Aim of the project was to improve epidemiological data collection via direct connection among ED and allergy network; moreover, we tried to provide a quick and proper evaluation of all reported patients, identifying, when possible, the agent responsible for anaphylaxis, to provide instructions on how to minimize future exposure; as all individuals at risk for anaphylaxis should carry and know how to self-administer epinephrine, we managed to provide auto injector and proper training when appropriate. A follow up on readmissions was carried out during the study and four months later. In a 20 months observation period (2013/2014), 205 patients were reported: it was possible to reach a diagnosis and risk assessment in 64

  11. The Visual Causality Analyst: An Interactive Interface for Causal Reasoning.

    PubMed

    Wang, Jun; Mueller, Klaus

    2016-01-01

    Uncovering the causal relations that exist among variables in multivariate datasets is one of the ultimate goals in data analytics. Causation is related to correlation but correlation does not imply causation. While a number of casual discovery algorithms have been devised that eliminate spurious correlations from a network, there are no guarantees that all of the inferred causations are indeed true. Hence, bringing a domain expert into the casual reasoning loop can be of great benefit in identifying erroneous casual relationships suggested by the discovery algorithm. To address this need we present the Visual Causal Analyst-a novel visual causal reasoning framework that allows users to apply their expertise, verify and edit causal links, and collaborate with the causal discovery algorithm to identify a valid causal network. Its interface consists of both an interactive 2D graph view and a numerical presentation of salient statistical parameters, such as regression coefficients, p-values, and others. Both help users in gaining a good understanding of the landscape of causal structures particularly when the number of variables is large. Our framework is also novel in that it can handle both numerical and categorical variables within one unified model and return plausible results. We demonstrate its use via a set of case studies using multiple practical datasets. PMID:26529703

  12. "The Maasai Need Cows and the Cows Need Maasai," the Use of a Photovoice Approach to Assess Animal Health Needs.

    PubMed

    van der Meer, Frank; Clancy, Eoin; Thomas, Adam; Kutz, Susan; Hatfield, Jennifer; Orsel, Karin

    2015-01-01

    The Maasai pastoralists in sub-Saharan Africa depend on their livestock for income and food. Livestock production can be significantly improved by addressing animal health concerns. We explored the use of photovoice, a participatory action research method, to strengthen our understanding of the Maasai's animal health needs. Nine interviewees, representing warriors, elders, and women, identified animal, social, and human health themes. The use of photography provided a new medium for Maasai to express their needs and a focus for researcher-participant communications, thereby facilitating new insights across language and cultural barriers. PMID:26664973

  13. Indoor air and human exposure assessment--needs and approaches.

    PubMed

    Kotzias, Dimitris

    2005-07-01

    The Commission launched on June 9, 2004 the Environment and Health Action Plan to reduce diseases caused by a polluted environment. The plan would develop an EU system integrating information on the state of the environment, the ecosystem and human health. The action plan identifies 13 actions (including an action on indoor air quality), which refer to initiatives on how to better understand the environment-health link and establish how environmental exposure leads to epidemiological effects. The ultimate goal of the proposed "Environment and Health Strategy" is to develop an environment and health "cause-effect framework" that will provide the necessary information for the development of Community policy dealing with sources and the impact pathway of health stressors. The need for policy-science interface in the EU guided in the last few years the research on indoor air pollution. In particular, the lack of information regarding human exposure to air pollutants makes it necessary, in line with the Environment and Health Action Plan, to develop targeted strategies to evaluate the impact of indoor air pollution on human health. This includes apart from specific measurements in selected confined spaces (homes, schools, public buildings, etc.), large-scale monitoring campaigns at European level, specifically designed to assess indoor and outdoor air quality and personal exposure to pollutants in combination with micro-environmental activity patterns. Information from these studies will be considered as crucial for a first evaluation of the overall situation in indoor environments and the possible sources and source strengths of pollutants to which humans are exposed during working, commuting and rest time. As a first approach to systematically evaluate the relationship between indoor air pollution and human (chronic) exposure to pollutants, we started at the end of 2003 with the AIRMEX project (Indoor Air Monitoring and Exposure Assessment Study). In the frame of

  14. Computational approach in estimating the need of ditch network maintenance

    NASA Astrophysics Data System (ADS)

    Lauren, Ari; Hökkä, Hannu; Launiainen, Samuli; Palviainen, Marjo; Repo, Tapani; Leena, Finer; Piirainen, Sirpa

    2015-04-01

    Ditch network maintenance (DNM), implemented annually in 70 000 ha area in Finland, is the most controversial of all forest management practices. Nationwide, it is estimated to increase the forest growth by 1…3 million m3 per year, but simultaneously to cause 65 000 tons export of suspended solids and 71 tons of phosphorus (P) to water courses. A systematic approach that allows simultaneous quantification of the positive and negative effects of DNM is required. Excess water in the rooting zone slows the gas exchange and decreases biological activity interfering with the forest growth in boreal forested peatlands. DNM is needed when: 1) the excess water in the rooting zone restricts the forest growth before the DNM, and 2) after the DNM the growth restriction ceases or decreases, and 3) the benefits of DNM are greater than the caused adverse effects. Aeration in the rooting zone can be used as a drainage criterion. Aeration is affected by several factors such as meteorological conditions, tree stand properties, hydraulic properties of peat, ditch depth, and ditch spacing. We developed a 2-dimensional DNM simulator that allows the user to adjust these factors and to evaluate their effect on the soil aeration at different distance from the drainage ditch. DNM simulator computes hydrological processes and soil aeration along a water flowpath between two ditches. Applying daily time step it calculates evapotranspiration, snow accumulation and melt, infiltration, soil water storage, ground water level, soil water content, air-filled porosity and runoff. The model performance in hydrology has been tested against independent high frequency field monitoring data. Soil aeration at different distance from the ditch is computed under steady-state assumption using an empirical oxygen consumption model, simulated air-filled porosity, and diffusion coefficient at different depths in soil. Aeration is adequate and forest growth rate is not limited by poor aeration if the

  15. Introduction to Causal Dynamical Triangulations

    NASA Astrophysics Data System (ADS)

    Görlich, Andrzej

    The method of causal dynamical triangulations is a non-perturbative and background-independent approach to quantum theory of gravity. In this review we present recent results obtained within the four dimensional model of causal dynamical triangulations. We describe the phase structure of the model and demonstrate how a macroscopic four-dimensional de Sitter universe emerges dynamically from the full gravitational path integral. We show how to reconstruct the effective action describing scale factor fluctuations from Monte Carlo data.

  16. Quantum causal modelling

    NASA Astrophysics Data System (ADS)

    Costa, Fabio; Shrapnel, Sally

    2016-06-01

    Causal modelling provides a powerful set of tools for identifying causal structure from observed correlations. It is well known that such techniques fail for quantum systems, unless one introduces ‘spooky’ hidden mechanisms. Whether one can produce a genuinely quantum framework in order to discover causal structure remains an open question. Here we introduce a new framework for quantum causal modelling that allows for the discovery of causal structure. We define quantum analogues for core features of classical causal modelling techniques, including the causal Markov condition and faithfulness. Based on the process matrix formalism, this framework naturally extends to generalised structures with indefinite causal order.

  17. The Power of Behavioural Approaches--We Need a Revival

    ERIC Educational Resources Information Center

    Buckley, Sue

    2008-01-01

    Behavioural approaches can be used effectively to teach new skills and to change behaviours that are challenging and not socially adaptive. The behaviour modification approach--now called applied behaviour analysis--is based on the assumption that all behaviours are learned, both the useful ones (new skills) and the ones that are not so useful…

  18. Meeting the Needs of LGBTQ Youth: A "Relational Assets" Approach

    ERIC Educational Resources Information Center

    Sadowski, Michael; Chow, Stephen; Scanlon, Constance P.

    2009-01-01

    Drawing primarily on three case studies, this article proposes a framework that those concerned about the welfare of lesbian, gay, bisexual, transgender, queer, and questioning (LGBTQ) youth can consider when developing, evaluating, or arguing for more effective programming: a relational assets approach. The relational assets approach merges the…

  19. We need theoretical physics approaches to study living systems

    NASA Astrophysics Data System (ADS)

    Blagoev, Krastan B.; Shukla, Kamal; affil="3" >Herbert Levine,

    2013-08-01

    , nor collect data on the kinetics of the many complex reactions. Instead, the focus was on formulating two- or three-component reaction-diffusion equations (e.g. the Oregonator), which could explain such generic features as the existence of rotating spiral waves (and their instability), the transition to chaos, the control of the reaction by light etc. By stressing mechanism instead of meticulous detail, one could understand the system even if there were still components and interactions waiting to be cataloged and quantified. In living systems, this way of thinking is even more crucial. A leading biologist once remarked to one of us that a calculation of in vivo cytoskeletal dynamics that did not take into account the fact that the particular cell in question had more than ten isoforms of actin could not possibly be correct. We need to counter that any calculation which takes into account all these isoforms is overwhelmingly likely to be vastly under-constrained and ultimately not useful. Adding more details can often bring us further from reality. Of course, the challenge for models is then falsification, i.e., finding robust predictions which can be directly tested experimentally. The most severe criticism, to quote Pauli, remains that 'your model is not even wrong.' Is this approach proving successful? In many cases it is too early to tell, but simple models have already proved useful in understanding protein folding, directed cell motility, gene expression variability and even laboratory-scale Darwinian evolution. One could argue as well that the extremely influential Hodgkin-Huxley approach to the action potential in neurons is a vastly oversimplified description and that is why it is tractable and compelling. There are other cases, however, where the model was too simple—the simple Turing instability does not account for Drosophila segment formation [2] and the binary state relaxational dynamics of the Hopfield model may prove incapable of explaining memory

  20. An Approach to Meeting Managements Needs for Financial Information

    ERIC Educational Resources Information Center

    Norberg, Douglas; Spilka, Leonard S.

    1973-01-01

    A discussion of the Automated Management Planning and Controls System (AMPACS) that is being designed for public television stations in order to provide much needed timely and complete information upon which management can base its decisions. (Author/HB)

  1. Causal reasoning with forces

    PubMed Central

    Wolff, Phillip; Barbey, Aron K.

    2015-01-01

    Causal composition allows people to generate new causal relations by combining existing causal knowledge. We introduce a new computational model of such reasoning, the force theory, which holds that people compose causal relations by simulating the processes that join forces in the world, and compare this theory with the mental model theory (Khemlani et al., 2014) and the causal model theory (Sloman et al., 2009), which explain causal composition on the basis of mental models and structural equations, respectively. In one experiment, the force theory was uniquely able to account for people's ability to compose causal relationships from complex animations of real-world events. In three additional experiments, the force theory did as well as or better than the other two theories in explaining the causal compositions people generated from linguistically presented causal relations. Implications for causal learning and the hierarchical structure of causal knowledge are discussed. PMID:25653611

  2. Expectations and Interpretations During Causal Learning

    PubMed Central

    Luhmann, Christian C.; Ahn, Woo-kyoung

    2012-01-01

    In existing models of causal induction, 4 types of covariation information (i.e., presence/absence of an event followed by presence/absence of another event) always exert identical influences on causal strength judgments (e.g., joint presence of events always suggests a generative causal relationship). In contrast, we suggest that, due to expectations developed during causal learning, learners give varied interpretations to covariation information as it is encountered and that these interpretations influence the resulting causal beliefs. In Experiments 1A–1C, participants’ interpretations of observations during a causal learning task were dynamic, expectation based, and, furthermore, strongly tied to subsequent causal judgments. Experiment 2 demonstrated that adding trials of joint absence or joint presence of events, whose roles have been traditionally interpreted as increasing causal strengths, could result in decreased overall causal judgments and that adding trials where one event occurs in the absence of another, whose roles have been traditionally interpreted as decreasing causal strengths, could result in increased overall causal judgments. We discuss implications for traditional models of causal learning and how a more top-down approach (e.g., Bayesian) would be more compatible with the current findings. PMID:21534705

  3. A new approach to assessing skill needs of senior managers.

    PubMed

    Griffith, John R; Warden, Gail L; Neighbors, Kamilah; Shim, Beth

    2002-01-01

    Management of health care organizations must improve to meet the well-documented challenges of quality improvement and cost control. Other industries have developed the tools--entry education, mentoring, planned mid-career formal education and experience, and special programs for senior management. The purpose of this paper is to pilot test an alternative method to identify competencies and performance of health care executives. We propose using formal lists of technical, interpersonal, and strategic competencies and specific real events chosen by the respondent to identify and prioritize competencies. Results of a trial with 30 large health care system CEOs and 15 early careerists demonstrate that the method reveals useful depth and detail about managers' educational needs. The results suggest that current thinking about managerial education and learning patterns may be seriously inadequate in several respects. The continued improvement of U.S. health care is a pressing national concern. Quality of care is highly variable and substantially deficient in many institutions (Chassin and Galvin 1998; Committee on Quality of Health Care in America 2001). "Quality improvement should be the essential business strategy for healthcare in the 21st century (Kizer 2001)." Productivity improvements will be essential to balance cost pressures from an aging population and growing technology (Heffler, et al. 2002). Skillful management is necessary to improve quality and productivity. Teams of dozens of caregivers are often required to improve a patient's health. The organizations that provide care have grown larger in response to the greater cost, complexity of operation and finance, and evidence of the success of scale in other industries. While many small professional practices, hospitals, and nursing homes remain, consolidation has created a few dozen provider and intermediary organizations exceeding a billion dollars a year in expenditures. These large health care

  4. “Upstream Analysis”: An Integrated Promoter-Pathway Analysis Approach to Causal Interpretation of Microarray Data

    PubMed Central

    Koschmann, Jeannette; Bhar, Anirban; Stegmaier, Philip; Kel, Alexander E.; Wingender, Edgar

    2015-01-01

    A strategy is presented that allows a causal analysis of co-expressed genes, which may be subject to common regulatory influences. A state-of-the-art promoter analysis for potential transcription factor (TF) binding sites in combination with a knowledge-based analysis of the upstream pathway that control the activity of these TFs is shown to lead to hypothetical master regulators. This strategy was implemented as a workflow in a comprehensive bioinformatic software platform. We applied this workflow to gene sets that were identified by a novel triclustering algorithm in naphthalene-induced gene expression signatures of murine liver and lung tissue. As a result, tissue-specific master regulators were identified that are known to be linked with tumorigenic and apoptotic processes. To our knowledge, this is the first time that genes of expression triclusters were used to identify upstream regulators.

  5. We need theoretical physics approaches to study living systems

    NASA Astrophysics Data System (ADS)

    Blagoev, Krastan B.; Shukla, Kamal; affil="3" >Herbert Levine,

    2013-08-01

    , nor collect data on the kinetics of the many complex reactions. Instead, the focus was on formulating two- or three-component reaction-diffusion equations (e.g. the Oregonator), which could explain such generic features as the existence of rotating spiral waves (and their instability), the transition to chaos, the control of the reaction by light etc. By stressing mechanism instead of meticulous detail, one could understand the system even if there were still components and interactions waiting to be cataloged and quantified. In living systems, this way of thinking is even more crucial. A leading biologist once remarked to one of us that a calculation of in vivo cytoskeletal dynamics that did not take into account the fact that the particular cell in question had more than ten isoforms of actin could not possibly be correct. We need to counter that any calculation which takes into account all these isoforms is overwhelmingly likely to be vastly under-constrained and ultimately not useful. Adding more details can often bring us further from reality. Of course, the challenge for models is then falsification, i.e., finding robust predictions which can be directly tested experimentally. The most severe criticism, to quote Pauli, remains that 'your model is not even wrong.' Is this approach proving successful? In many cases it is too early to tell, but simple models have already proved useful in understanding protein folding, directed cell motility, gene expression variability and even laboratory-scale Darwinian evolution. One could argue as well that the extremely influential Hodgkin-Huxley approach to the action potential in neurons is a vastly oversimplified description and that is why it is tractable and compelling. There are other cases, however, where the model was too simple—the simple Turing instability does not account for Drosophila segment formation [2] and the binary state relaxational dynamics of the Hopfield model may prove incapable of explaining memory

  6. Causal pathways linking Farm to School to childhood obesity prevention.

    PubMed

    Joshi, Anupama; Ratcliffe, Michelle M

    2012-08-01

    Farm to School programs are rapidly gaining attention as a potential strategy for preventing childhood obesity; however, the causal linkages between Farm to School activities and health outcomes are not well documented. To capitalize on the increased interest in and momentum for Farm to School, researchers and practitioners need to move from developing and implementing evidence informed programs and policies to ones that are evidence-based. The purpose of this article is to outline a framework for facilitating an evidence base for Farm to School programs and policies through a systematic and coordinated approach. Employing the concepts of causal pathways, the authors introduce a proposed framework for organizing and systematically testing out multiple hypotheses (or potential causal links) for how, why, and under what conditions Farm to School Inputs and Activities may result in what Outputs, Effects, and Impacts. Using the causal pathways framework may help develop and test competing hypotheses, identify multicausality, strength, and interactions of causes, and discern the difference between catalysts and causes. In this article, we introduce causal pathways, present menus of potential independent and dependent variables from which to create and test causal pathways linking Farm to School interventions and their role in preventing childhood obesity, discuss their applicability to Farm to School research and practice, and outline proposed next steps for developing a coordinated research framework for Farm to School programs. PMID:22867068

  7. The Substance Abuse Counseling Needs of Women in the Criminal Justice System: A Needs Assessment Approach

    ERIC Educational Resources Information Center

    Laux, John M.; Dupuy, Paula J.; Moe, Jeffry L.; Cox, Jane A.; Lambert, Eric; Ventura, Lois A.; Williamson, Celia; Benjamin, Barbaranne J.

    2008-01-01

    The authors assessed the substance abuse counseling needs of women in the criminal justice system using interviews (n = 304) and surveys (n = 1,170). On the basis of the results, the authors call for gender-specific treatment as well as family-oriented support for women who are mothers.

  8. A Theoretical Approach to Information Needs Across Different Healthcare Stakeholders

    NASA Astrophysics Data System (ADS)

    Raitoharju, Reetta; Aarnio, Eeva

    Increased access to medical information can lead to information overload among both the employees in the healthcare sector as well as among healthcare consumers. Moreover, medical information can be hard to understand for consumers who have no prerequisites for interpreting and understanding it. Information systems (e.g. electronic patient records) are normally designed to meet the demands of one professional group, for instance those of physicians. Therefore, the same information in the same form is presented to all the users of the systems regardless of the actual need or prerequisites. The purpose of this article is to illustrate the differences in information needs across different stakeholders in healthcare. A literature review was conducted to collect examples of these different information needs. Based on the findings the role of more user specific information systems is discussed.

  9. Causal Responsibility and Counterfactuals

    PubMed Central

    Lagnado, David A; Gerstenberg, Tobias; Zultan, Ro'i

    2013-01-01

    How do people attribute responsibility in situations where the contributions of multiple agents combine to produce a joint outcome? The prevalence of over-determination in such cases makes this a difficult problem for counterfactual theories of causal responsibility. In this article, we explore a general framework for assigning responsibility in multiple agent contexts. We draw on the structural model account of actual causation (e.g., Halpern & Pearl, 2005) and its extension to responsibility judgments (Chockler & Halpern, 2004). We review the main theoretical and empirical issues that arise from this literature and propose a novel model of intuitive judgments of responsibility. This model is a function of both pivotality (whether an agent made a difference to the outcome) and criticality (how important the agent is perceived to be for the outcome, before any actions are taken). The model explains empirical results from previous studies and is supported by a new experiment that manipulates both pivotality and criticality. We also discuss possible extensions of this model to deal with a broader range of causal situations. Overall, our approach emphasizes the close interrelations between causality, counterfactuals, and responsibility attributions. PMID:23855451

  10. A Fault Tree Approach to Needs Assessment -- An Overview.

    ERIC Educational Resources Information Center

    Stephens, Kent G.

    A "failsafe" technology is presented based on a new unified theory of needs assessment. Basically the paper discusses fault tree analysis as a technique for enhancing the probability of success in any system by analyzing the most likely modes of failure that could occur and then suggesting high priority avoidance strategies for those failure…

  11. Standards for Teleprocessing; New Approaches for New Needs.

    ERIC Educational Resources Information Center

    Istvan, Edwin J.

    The rapidly expanding use of teleprocessing, which is taken to mean automated data processing (ADP) which makes direct use of data transmission via switched or long distance non-switched telecommunications facilities, has highlighted the urgent need for the development of standards for data communications and the computer-communications interface.…

  12. Complex vestibular macular anatomical relationships need a synthetic approach

    NASA Technical Reports Server (NTRS)

    Ross, M. D.

    2001-01-01

    Mammalian vestibular maculae are anatomically organized for complex parallel processing of linear acceleration information. Anatomical findings in rat maculae are provided in order to underscore this complexity, which is little understood functionally. This report emphasizes that a synthetic approach is critical to understanding how maculae function and the kind of information they conduct to the brain.

  13. Respiratory sensitization and allergy: Current research approaches and needs

    SciTech Connect

    Boverhof, Darrell R. Billington, Richard; Gollapudi, B. Bhaskar; Hotchkiss, John A.; Krieger, Shannon M.; Poole, Alan; Wiescinski, Connie M.; Woolhiser, Michael R.

    2008-01-01

    There are currently no accepted regulatory models for assessing the potential of a substance to cause respiratory sensitization and allergy. In contrast, a number of models exist for the assessment of contact sensitization and allergic contact dermatitis (ACD). Research indicates that respiratory sensitizers may be identified through contact sensitization assays such as the local lymph node assay, although only a small subset of the compounds that yield positive results in these assays are actually respiratory sensitizers. Due to the increasing health concerns associated with occupational asthma and the impending directives on the regulation of respiratory sensitizers and allergens, an approach which can identify these compounds and distinguish them from contact sensitizers is required. This report discusses some of the important contrasts between respiratory allergy and ACD, and highlights several prominent in vivo, in vitro and in silico approaches that are being applied or could be further developed to identify compounds capable of causing respiratory allergy. Although a number of animal models have been used for researching respiratory sensitization and allergy, protocols and endpoints for these approaches are often inconsistent, costly and difficult to reproduce, thereby limiting meaningful comparisons of data between laboratories and development of a consensus approach. A number of emerging in vitro and in silico models show promise for use in the characterization of contact sensitization potential and should be further explored for their ability to identify and differentiate contact and respiratory sensitizers. Ultimately, the development of a consistent, accurate and cost-effective model will likely incorporate a number of these approaches and will require effective communication, collaboration and consensus among all stakeholders.

  14. Technology Development Roadmaps - a Systematic Approach to Maturing Needed Technologies

    SciTech Connect

    John W. Colllins; Layne Pincock

    2010-07-01

    Abstract. Planning and decision making represent important challenges for all projects. This paper presents the steps needed to assess technical readiness and determine the path forward to mature the technologies required for the Next Generation Nuclear Plant. A Technology Readiness Assessment is used to evaluate the required systems, subsystems, and components (SSC) comprising the desired plant architecture and assess the SSCs against established Technology Readiness Levels (TRLs). A validated TRL baseline is then established for the proposed physical design. Technology Development Roadmaps are generated to define the path forward and focus project research and development and engineering tasks on advancing the technologies to increasing levels of maturity. Tasks include modeling, testing, bench-scale demonstrations, pilot-scale demonstrations, and fully integrated prototype demonstrations. The roadmaps identify precise project objectives and requirements; create a consensus vision of project needs; provide a structured, defensible, decision-based project plan; and, minimize project costs and schedules.

  15. Systems approach to chemical spill response information needs

    SciTech Connect

    Parnarouskis, M.C.; Flessner, M.F.; Potts, R.G.

    1980-01-01

    The Chemical Hazards Response Information System (CHRIS) has been specifically designed to meet the emergency needs of US Coast Guard field personnel, currently providing them with information on 900 hazardous chemicals, with methods of predicting hazards resulting from accidental discharges, and with procedures for selecting and implementing response to accident discharges. The major components of CHRIS and the computerized hazard assessment models within the Hazard Assessment Computer System are described in detail.

  16. Making the Case for Causal Dynamical Triangulations

    NASA Astrophysics Data System (ADS)

    Cooperman, Joshua H.

    2015-11-01

    The aim of the causal dynamical triangulations approach is to define nonperturbatively a quantum theory of gravity as the continuum limit of a lattice-regularized model of dynamical geometry. My aim in this paper is to give a concise yet comprehensive, impartial yet personal presentation of the causal dynamical triangulations approach.

  17. Campbell's and Rubin's Perspectives on Causal Inference

    ERIC Educational Resources Information Center

    West, Stephen G.; Thoemmes, Felix

    2010-01-01

    Donald Campbell's approach to causal inference (D. T. Campbell, 1957; W. R. Shadish, T. D. Cook, & D. T. Campbell, 2002) is widely used in psychology and education, whereas Donald Rubin's causal model (P. W. Holland, 1986; D. B. Rubin, 1974, 2005) is widely used in economics, statistics, medicine, and public health. Campbell's approach focuses on…

  18. Pacific Island Pharmacovigilance: The Need for a Different Approach.

    PubMed

    McEwen, John; Vestergaard, Lasse S; Sanburg, Amanda L C

    2016-10-01

    Many Pacific Island countries (PICs) are recipients of funding support from the Global Fund to Fight AIDS, Tuberculosis and Malaria (Global Fund). However, most of these countries cannot be expected to meet Global Fund and World Health Organization (WHO) minimum requirements for a functioning pharmacovigilance (PV) system. We argue that a different approach is required to move PV forward in such countries. Although the long-term aim is to build adequate national PV capacity, we propose an approach in which resources are focused initially towards ensuring a proper system for the reporting of "problems with medicines" such as substandard and counterfeit products. The limited health system resources in these countries require that PV will be supported by some of the organizations also giving funding aid for the supply of medicines. PMID:27364632

  19. Why health care corruption needs a new approach.

    PubMed

    Radin, Dagmar

    2016-07-01

    While corruption has been at the center of academic studies and on the agenda of international organizations for a couple of decades, in the health care sector corruption has not generated much interest or progress. At the centre of this issue is the lack of an interdisciplinary approach, which is warranted given the complexity of the issue and the lack of cooperation between STET scientifically rigorous academics and policy-makers, leaving room for more cooperation and progress. PMID:26608191

  20. Effect of Age on Complexity and Causality of the Cardiovascular Control: Comparison between Model-Based and Model-Free Approaches

    PubMed Central

    Porta, Alberto; Faes, Luca; Bari, Vlasta; Marchi, Andrea; Bassani, Tito; Nollo, Giandomenico; Perseguini, Natália Maria; Milan, Juliana; Minatel, Vinícius; Borghi-Silva, Audrey; Takahashi, Anielle C. M.; Catai, Aparecida M.

    2014-01-01

    The proposed approach evaluates complexity of the cardiovascular control and causality among cardiovascular regulatory mechanisms from spontaneous variability of heart period (HP), systolic arterial pressure (SAP) and respiration (RESP). It relies on construction of a multivariate embedding space, optimization of the embedding dimension and a procedure allowing the selection of the components most suitable to form the multivariate embedding space. Moreover, it allows the comparison between linear model-based (MB) and nonlinear model-free (MF) techniques and between MF approaches exploiting local predictability (LP) and conditional entropy (CE). The framework was applied to study age-related modifications of complexity and causality in healthy humans in supine resting (REST) and during standing (STAND). We found that: 1) MF approaches are more efficient than the MB method when nonlinear components are present, while the reverse situation holds in presence of high dimensional embedding spaces; 2) the CE method is the least powerful in detecting age-related trends; 3) the association of HP complexity on age suggests an impairment of cardiac regulation and response to STAND; 4) the relation of SAP complexity on age indicates a gradual increase of sympathetic activity and a reduced responsiveness of vasomotor control to STAND; 5) the association from SAP to HP on age during STAND reveals a progressive inefficiency of baroreflex; 6) the reduced connection from HP to SAP with age might be linked to the progressive exploitation of Frank-Starling mechanism at REST and to the progressive increase of peripheral resistances during STAND; 7) at REST the diminished association from RESP to HP with age suggests a vagal withdrawal and a gradual uncoupling between respiratory activity and heart; 8) the weakened connection from RESP to SAP with age might be related to the progressive increase of left ventricular thickness and vascular stiffness and to the gradual decrease of

  1. Analytical Approaches to Verify Food Integrity: Needs and Challenges.

    PubMed

    Stadler, Richard H; Tran, Lien-Anh; Cavin, Christophe; Zbinden, Pascal; Konings, Erik J M

    2016-09-01

    A brief overview of the main analytical approaches and practices to determine food authenticity is presented, addressing, as well, food supply chain and future requirements to more effectively mitigate food fraud. Food companies are introducing procedures and mechanisms that allow them to identify vulnerabilities in their food supply chain under the umbrella of a food fraud prevention management system. A key step and first line of defense is thorough supply chain mapping and full transparency, assessing the likelihood of fraudsters to penetrate the chain at any point. More vulnerable chains, such as those where ingredients and/or raw materials are purchased through traders or auctions, may require a higher degree of sampling, testing, and surveillance. Access to analytical tools is therefore pivotal, requiring continuous development and possibly sophistication in identifying chemical markers, data acquisition, and modeling. Significant progress in portable technologies is evident already today, for instance, as in the rapid testing now available at the agricultural level. In the near future, consumers may also have the ability to scan products in stores or at home to authenticate labels and food content. For food manufacturers, targeted analytical methods complemented by untargeted approaches are end control measures at the factory gate when the material is delivered. In essence, testing for food adulterants is an integral part of routine QC, ideally tailored to the risks in the individual markets and/or geographies or supply chains. The development of analytical methods is a first step in verifying the compliance and authenticity of food materials. A next, more challenging step is the successful establishment of global consensus reference methods as exemplified by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals initiative, which can serve as an approach that could also be applied to methods for contaminants and adulterants in food. The food

  2. Insights into Platelet Storage and the Need for Multiple Approaches.

    PubMed

    Handigund, Mallikarjun; Cho, Yong Gon

    2015-01-01

    Upon accidental injury and the treatment of many diseases, patients may need a transfusion of blood components in order to achieve hemostasis. Platelets are small enucleated cells derived from bone marrow megakaryocytes that undergo change upon activation at sites of vascular injury and play a vital role in vascular repair and antimicrobial host defense, collectively contributing to hemostasis. They are the common blood components transfused whenever there is need, but supplies do not equal the demand as platelets are required in many medical and surgical procedures. In addition, surplus supplies of platelet concentrate are often discarded as they have a short shelf life. Currently, platelet concentrates are stored at room temperature for a maximum of 5 days from the date of collection; the temporal aspect is an added hurdle in the growing demand for platelet concentrates. Many investigations have been carried out in attempt to improve the quality and lengthen the shelf life of platelets, but the few that have succeeded are not commercially viable. Moreover, currently there is a declining trend in platelet research, quelling the hope of platelet storage improvement. Successful strategies would be a boon for medicine in particular and humanity in general. This review deals with past and current efforts toward improving the quality of platelet concentrates by reducing platelet storage lesions and increasing the viable storage period for platelets. Also presented are new perspectives based on past and current efforts, which should be investigated for platelet research in this decade. PMID:26663804

  3. Health in cities: is a systems approach needed?

    PubMed

    Diez Roux, Ana V

    2015-11-01

    This paper reviews the potential utility of using the concepts and tools of systems to understand and act on health in cities. The basic elements of systems approaches and the links between cities as systems and population health as emerging from the functioning of a system are reviewed. The paper also discusses implications of systems thinking for urban health including the development of dynamic conceptual models, the use of new tools, the integration of data in new ways and the identification of data gaps, and the formulation of different kinds of questions and identification of new policies. The paper concludes with a review of caveats and challenges. PMID:26648353

  4. Workforce Development: A Survey of Industry Needs and Training Approaches

    SciTech Connect

    Ventre, Jerry; Weissman, Jane

    2009-04-01

    This paper presents information and data collected during 2008 on PV workforce needs by the Interstate Renewable Energy Council for the U.S. Department of Energy. The data was collected from licensed contractors, PV practitioners, educators and expert instructors at training sessions, and at focus group and advisory committee meetings. Respondents were primarily from three states: Florida, New York and California. Other states were represented, but to a lesser extent. For data collection, a 12-item questionnaire was developed that addressed key workforce development issues from the perspectives of both the PV industry and training institutions. A total of 63 responses were collected, although not every respondent answered every question. Industry representatives slightly outnumbered the educators, although the difference in responses was not significant.

  5. Ramadan focused diabetes education; a much needed approach.

    PubMed

    Hassanein, Mohamed

    2015-05-01

    Ramadan Fasting is passionately practiced by millions of Muslims with diabetes across the globe. Structured education is recommended by the various diabetes societies to empower the person with diabetes to better self manage their condition. Indeed, Ramadan focused diabetes education has been shown to be beneficial to Muslim persons with diabetes wishing to fast in the Holy month of Ramadan. Hence, many national and international guidelines stress the importance of Ramadan focused structured education. Such education is targeted at the general public including the religious authorities to raise their awareness about diabetes and Ramadan, healthcare professionals to improve their clinical skills on managing diabetes during Ramadan and most importantly for the person with diabetes to help them to sail through the month of Ramadan safely. Consequently, any educational programme needs to be simple, clear and in the person with diabetes own language. Studies have shown that such a practice whether in a group session or one to one can help to reduce risk of hypoglycaemia and indeed other possible complications. Self-monitoring of blood glucose is a crucial element of Ramadan focused diabetes education to empower the person with the information and help in behaviour change for safer fast during Ramadan. PMID:26013796

  6. Sociotechnical approaches to workplace safety: Research needs and opportunities

    PubMed Central

    Robertson, Michelle M.; Hettinger, Lawrence J.; Waterson, Patrick E.; Ian Noy, Y.; Dainoff, Marvin J.; Leveson, Nancy G.; Carayon, Pascale; Courtney, Theodore K.

    2015-01-01

    The sociotechnical systems perspective offers intriguing and potentially valuable insights into problems associated with workplace safety. While formal sociotechnical systems thinking originated in the 1950s, its application to the analysis and design of sustainable, safe working environments has not been fully developed. To that end, a Hopkinton Conference was organised to review and summarise the state of knowledge in the area and to identify research priorities. A group of 26 international experts produced collaborative articles for this special issue of Ergonomics, and each focused on examining a key conceptual, methodological and/or theoretical issue associated with sociotechnical systems and safety. In this concluding paper, we describe the major conference themes and recommendations. These are organised into six topic areas: (1) Concepts, definitions and frameworks, (2) defining research methodologies, (3) modelling and simulation, (4) communications and decision-making, (5) sociotechnical attributes of safe and unsafe systems and (6) potential future research directions for sociotechnical systems research. Practitioner Summary: Sociotechnical complexity, a characteristic of many contemporary work environments, presents potential safety risks that traditional approaches to workplace safety may not adequately address. In this paper, we summarise the investigations of a group of international researchers into questions associated with the application of sociotechnical systems thinking to improve worker safety. PMID:25728246

  7. The concept of causality in image reconstruction

    SciTech Connect

    Llacer, J.; Veklerov, E.; Nunez, J.

    1988-09-01

    Causal images in emission tomography are defined as those which could have generated the data by the statistical process that governs the physics of the measurement. The concept of causality was previously applied to deciding when to stop the MLE iterative procedure in PET. The present paper further explores the concept, indicates the difficulty of carrying out a correct hypothesis testing for causality, discusses the assumption needed to justify the tests proposed and discusses a possible methodology for a justification of that assumption. The paper also describes several methods that we have found to generate causal images and it shows that the set of causal images is rather large. This set includes images judged to be superior to the best maximum likelihood images, but it also includes unacceptable and noisy images. The paper concludes by proposing to use causality as a constraint in optimization problems. 16 refs., 5 figs.

  8. Causal Mediation Analysis: Warning! Assumptions Ahead

    ERIC Educational Resources Information Center

    Keele, Luke

    2015-01-01

    In policy evaluations, interest may focus on why a particular treatment works. One tool for understanding why treatments work is causal mediation analysis. In this essay, I focus on the assumptions needed to estimate mediation effects. I show that there is no "gold standard" method for the identification of causal mediation effects. In…

  9. What Works Clearinghouse Quick Review: "Looking Beyond Enrollment: The Causal Effect of Need-Based Grants on College Access, Persistence, and Graduation"

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2013

    2013-01-01

    This study examined whether eligibility for the Florida Student Access Grant, a need-based grant for low-income students in Florida, affects college enrollment, credit accumulation, persistence over time in college, and, eventually, graduation. The sample for this study included seniors in Florida public high schools in 1999-2000 who submitted a…

  10. Looking beyond Enrollment: The Causal Effect of Need-Based Grants on College Access, Persistence, and Graduation. NBER Working Paper No. 19306

    ERIC Educational Resources Information Center

    Castleman, Benjamin L.; Long, Bridget Terry

    2013-01-01

    Gaps in average college success among students of differing backgrounds have persisted in the United States for decades. One of the primary ways governments have attempted to ameliorate such gaps is by providing need-based grants, but little evidence exists on the impacts of such aid on longer-term outcomes such as college persistence and degree…

  11. Illusions of causality at the heart of pseudoscience.

    PubMed

    Matute, Helena; Yarritu, Ion; Vadillo, Miguel A

    2011-08-01

    Pseudoscience, superstitions, and quackery are serious problems that threaten public health and in which many variables are involved. Psychology, however, has much to say about them, as it is the illusory perceptions of causality of so many people that needs to be understood. The proposal we put forward is that these illusions arise from the normal functioning of the cognitive system when trying to associate causes and effects. Thus, we propose to apply basic research and theories on causal learning to reduce the impact of pseudoscience. We review the literature on the illusion of control and the causal learning traditions, and then present an experiment as an illustration of how this approach can provide fruitful ideas to reduce pseudoscientific thinking. The experiment first illustrates the development of a quackery illusion through the testimony of fictitious patients who report feeling better. Two different predictions arising from the integration of the causal learning and illusion of control domains are then proven effective in reducing this illusion. One is showing the testimony of people who feel better without having followed the treatment. The other is asking participants to think in causal terms rather than in terms of effectiveness. PMID:21751996

  12. Model Averaging for Improving Inference from Causal Diagrams

    PubMed Central

    Hamra, Ghassan B.; Kaufman, Jay S.; Vahratian, Anjel

    2015-01-01

    Model selection is an integral, yet contentious, component of epidemiologic research. Unfortunately, there remains no consensus on how to identify a single, best model among multiple candidate models. Researchers may be prone to selecting the model that best supports their a priori, preferred result; a phenomenon referred to as “wish bias”. Directed acyclic graphs (DAGs), based on background causal and substantive knowledge, are a useful tool for specifying a subset of adjustment variables to obtain a causal effect estimate. In many cases, however, a DAG will support multiple, sufficient or minimally-sufficient adjustment sets. Even though all of these may theoretically produce unbiased effect estimates they may, in practice, yield somewhat distinct values, and the need to select between these models once again makes the research enterprise vulnerable to wish bias. In this work, we suggest combining adjustment sets with model averaging techniques to obtain causal estimates based on multiple, theoretically-unbiased models. We use three techniques for averaging the results among multiple candidate models: information criteria weighting, inverse variance weighting, and bootstrapping. We illustrate these approaches with an example from the Pregnancy, Infection, and Nutrition (PIN) study. We show that each averaging technique returns similar, model averaged causal estimates. An a priori strategy of model averaging provides a means of integrating uncertainty in selection among candidate, causal models, while also avoiding the temptation to report the most attractive estimate from a suite of equally valid alternatives. PMID:26270672

  13. Algorithm to assess causality after individual adverse events following immunizations.

    PubMed

    Halsey, Neal A; Edwards, Kathryn M; Dekker, Cornelia L; Klein, Nicola P; Baxter, Roger; Larussa, Philip; Marchant, Colin; Slade, Barbara; Vellozzi, Claudia

    2012-08-24

    Assessing individual reports of adverse events following immunizations (AEFI) can be challenging. Most published reviews are based on expert opinions, but the methods and logic used to arrive at these opinions are neither well described nor understood by many health care providers and scientists. We developed a standardized algorithm to assist in collecting and interpreting data, and to help assess causality after individual AEFI. Key questions that should be asked during the assessment of AEFI include: Is the diagnosis of the AEFI correct? Does clinical or laboratory evidence exist that supports possible causes for the AEFI other than the vaccine in the affected individual? Is there a known causal association between the AEFI and the vaccine? Is there strong evidence against a causal association? Is there a specific laboratory test implicating the vaccine in the pathogenesis? An algorithm can assist with addressing these questions in a standardized, transparent manner which can be tracked and reassessed if additional information becomes available. Examples in this document illustrate the process of using the algorithm to determine causality. As new epidemiologic and clinical data become available, the algorithm and guidelines will need to be modified. Feedback from users of the algorithm will be invaluable in this process. We hope that this algorithm approach can assist with educational efforts to improve the collection of key information on AEFI and provide a platform for teaching about causality assessment. PMID:22507656

  14. The Effects of a Model-Based Physics Curriculum Program with a Physics First Approach: A Causal-Comparative Study

    ERIC Educational Resources Information Center

    Liang, Ling L.; Fulmer, Gavin W.; Majerich, David M.; Clevenstine, Richard; Howanski, Raymond

    2012-01-01

    The purpose of this study is to examine the effects of a model-based introductory physics curriculum on conceptual learning in a Physics First (PF) Initiative. This is the first comparative study in physics education that applies the Rasch modeling approach to examine the effects of a model-based curriculum program combined with PF in the United…

  15. Developing Causal Understanding with Causal Maps: The Impact of Total Links, Temporal Flow, and Lateral Position of Outcome Nodes

    ERIC Educational Resources Information Center

    Jeong, Allan; Lee, Woon Jee

    2012-01-01

    This study examined some of the methodological approaches used by students to construct causal maps in order to determine which approaches help students understand the underlying causes and causal mechanisms in a complex system. This study tested the relationship between causal understanding (ratio of root causes correctly/incorrectly identified,…

  16. Causality and cosmic inflation

    SciTech Connect

    Vachaspati, Tanmay; Trodden, Mark

    2000-01-15

    In the context of inflationary models with a pre-inflationary stage, in which the Einstein equations are obeyed, the null energy condition is satisfied, and spacetime topology is trivial, we argue that homogeneity on super-Hubble scales must be assumed as an initial condition. Models in which inflation arises from field dynamics in a Friedmann-Robertson-Walker background fall into this class but models in which inflation originates at the Planck epoch may evade this conclusion. Our arguments rest on causality and general relativistic constraints on the structure of spacetime. We discuss modifications to existing scenarios that may avoid the need for initial large-scale homogeneity. (c) 1999 The American Physical Society.

  17. The Effects of a Model-Based Physics Curriculum Program with a Physics First Approach: a Causal-Comparative Study

    NASA Astrophysics Data System (ADS)

    Liang, Ling L.; Fulmer, Gavin W.; Majerich, David M.; Clevenstine, Richard; Howanski, Raymond

    2012-02-01

    The purpose of this study is to examine the effects of a model-based introductory physics curriculum on conceptual learning in a Physics First (PF) Initiative. This is the first comparative study in physics education that applies the Rasch modeling approach to examine the effects of a model-based curriculum program combined with PF in the United States. Five teachers and 301 students (in grades 9 through 12) in two mid-Atlantic high schools participated in the study. The students' conceptual learning was measured by the Force Concept Inventory (FCI). It was found that the ninth-graders enrolled in the model-based program in a PF initiative achieved substantially greater conceptual understanding of the physics content than those 11th-/12th-graders enrolled in the conventional non-modeling, non-PF program (Honors strand). For the 11th-/12th-graders enrolled in the non-PF, non-honors strands, the modeling classes also outperformed the conventional non-modeling classes. The instructional activity reports by students indicated that the model-based approach was generally implemented in modeling classrooms. A closer examination of the field notes and the classroom observation profiles revealed that the greatest inconsistencies in model-based teaching practices observed were related to classroom interactions or discourse. Implications and recommendations for future studies are also discussed.

  18. Recognising discourse causality triggers in the biomedical domain.

    PubMed

    Mihăilă, Claudiu; Ananiadou, Sophia

    2013-12-01

    Current domain-specific information extraction systems represent an important resource for biomedical researchers, who need to process vast amounts of knowledge in a short time. Automatic discourse causality recognition can further reduce their workload by suggesting possible causal connections and aiding in the curation of pathway models. We describe here an approach to the automatic identification of discourse causality triggers in the biomedical domain using machine learning. We create several baselines and experiment with and compare various parameter settings for three algorithms, i.e. Conditional Random Fields (CRF), Support Vector Machines (SVM) and Random Forests (RF). We also evaluate the impact of lexical, syntactic, and semantic features on each of the algorithms, showing that semantics improves the performance in all cases. We test our comprehensive feature set on two corpora containing gold standard annotations of causal relations, and demonstrate the need for more gold standard data. The best performance of 79.35% F-score is achieved by CRFs when using all three feature types. PMID:24372037

  19. The role of awareness campaigns in the improvement of separate collection rates of municipal waste among university students: A Causal Chain Approach.

    PubMed

    Saladié, Òscar; Santos-Lacueva, Raquel

    2016-02-01

    One of the main objectives of municipal waste management policies is to improve separate collection, both quantitatively and qualitatively. Several factors influence people behavior to recycling and, consequently, they play an important role to achieve the goals proposed in the management policies. People can improve separate collection rates because of a wide range of causes with different weight. Here, we have determined the uplift in probability to improve separate collection of municipal waste created by the awareness campaigns among 806 undergraduate students at Universitat Rovira i Virgili (Catalonia) by means of the Causal Chain Approach, a probabilistic method. A 73.2% state having improved separate collection in recent years and the most of them (75.4%) remember some awareness campaign. The results show the uplift in probability to improve separate collection attributable to the awareness campaigns is 17.9%. They should be taken into account by policy makers in charge of municipal waste management. Nevertheless, it must be assumed an awareness campaign will never be sufficient to achieve the objectives defined in municipal waste management programmes. PMID:26684055

  20. Granger causality revisited

    PubMed Central

    Friston, Karl J.; Bastos, André M.; Oswal, Ashwini; van Wijk, Bernadette; Richter, Craig; Litvak, Vladimir

    2014-01-01

    This technical paper offers a critical re-evaluation of (spectral) Granger causality measures in the analysis of biological timeseries. Using realistic (neural mass) models of coupled neuronal dynamics, we evaluate the robustness of parametric and nonparametric Granger causality. Starting from a broad class of generative (state-space) models of neuronal dynamics, we show how their Volterra kernels prescribe the second-order statistics of their response to random fluctuations; characterised in terms of cross-spectral density, cross-covariance, autoregressive coefficients and directed transfer functions. These quantities in turn specify Granger causality — providing a direct (analytic) link between the parameters of a generative model and the expected Granger causality. We use this link to show that Granger causality measures based upon autoregressive models can become unreliable when the underlying dynamics is dominated by slow (unstable) modes — as quantified by the principal Lyapunov exponent. However, nonparametric measures based on causal spectral factors are robust to dynamical instability. We then demonstrate how both parametric and nonparametric spectral causality measures can become unreliable in the presence of measurement noise. Finally, we show that this problem can be finessed by deriving spectral causality measures from Volterra kernels, estimated using dynamic causal modelling. PMID:25003817

  1. Management Development: The Need for an Eclectic Approach. Part 1. Classroom-Based Systems

    ERIC Educational Resources Information Center

    Cone, Wllliam F.

    1970-01-01

    We need an eclectic management development approach combining the best features of both classroom based systems (T groups, sensitivity training, games, university programs) and of such job based systems as coaching, counseling, and planned rotation. (LY)

  2. Spin foam models as energetic causal sets

    NASA Astrophysics Data System (ADS)

    Cortês, Marina; Smolin, Lee

    2016-04-01

    Energetic causal sets are causal sets endowed by a flow of energy-momentum between causally related events. These incorporate a novel mechanism for the emergence of space-time from causal relations [M. Cortês and L. Smolin, Phys. Rev. D 90, 084007 (2014); Phys. Rev. D 90, 044035 (2014)]. Here we construct a spin foam model which is also an energetic causal set model. This model is closely related to the model introduced in parallel by Wolfgang Wieland in [Classical Quantum Gravity 32, 015016 (2015)]. What makes a spin foam model also an energetic causal set is Wieland's identification of new degrees of freedom analogous to momenta, conserved at events (or four-simplices), whose norms are not mass, but the volume of tetrahedra. This realizes the torsion constraints, which are missing in previous spin foam models, and are needed to relate the connection dynamics to those of the metric, as in general relativity. This identification makes it possible to apply the new mechanism for the emergence of space-time to a spin foam model. Our formulation also makes use of Markopoulou's causal formulation of spin foams [arXiv:gr-qc/9704013]. These are generated by evolving spin networks with dual Pachner moves. This endows the spin foam history with causal structure given by a partial ordering of the events which are dual to four-simplices.

  3. The TEACH Method: An Interactive Approach for Teaching the Needs-Based Theories Of Motivation

    ERIC Educational Resources Information Center

    Moorer, Cleamon, Jr.

    2014-01-01

    This paper describes an interactive approach for explaining and teaching the Needs-Based Theories of Motivation. The acronym TEACH stands for Theory, Example, Application, Collaboration, and Having Discussion. This method can help business students to better understand and distinguish the implications of Maslow's Hierarchy of Needs,…

  4. Granger causality for state-space models

    NASA Astrophysics Data System (ADS)

    Barnett, Lionel; Seth, Anil K.

    2015-04-01

    Granger causality has long been a prominent method for inferring causal interactions between stochastic variables for a broad range of complex physical systems. However, it has been recognized that a moving average (MA) component in the data presents a serious confound to Granger causal analysis, as routinely performed via autoregressive (AR) modeling. We solve this problem by demonstrating that Granger causality may be calculated simply and efficiently from the parameters of a state-space (SS) model. Since SS models are equivalent to autoregressive moving average models, Granger causality estimated in this fashion is not degraded by the presence of a MA component. This is of particular significance when the data has been filtered, downsampled, observed with noise, or is a subprocess of a higher dimensional process, since all of these operations—commonplace in application domains as diverse as climate science, econometrics, and the neurosciences—induce a MA component. We show how Granger causality, conditional and unconditional, in both time and frequency domains, may be calculated directly from SS model parameters via solution of a discrete algebraic Riccati equation. Numerical simulations demonstrate that Granger causality estimators thus derived have greater statistical power and smaller bias than AR estimators. We also discuss how the SS approach facilitates relaxation of the assumptions of linearity, stationarity, and homoscedasticity underlying current AR methods, thus opening up potentially significant new areas of research in Granger causal analysis.

  5. Causal Learning Across Domains

    ERIC Educational Resources Information Center

    Schulz, Laura E.; Gopnik, Alison

    2004-01-01

    Five studies investigated (a) children's ability to use the dependent and independent probabilities of events to make causal inferences and (b) the interaction between such inferences and domain-specific knowledge. In Experiment 1, preschoolers used patterns of dependence and independence to make accurate causal inferences in the domains of…

  6. Causality in Classical Electrodynamics

    ERIC Educational Resources Information Center

    Savage, Craig

    2012-01-01

    Causality in electrodynamics is a subject of some confusion, especially regarding the application of Faraday's law and the Ampere-Maxwell law. This has led to the suggestion that we should not teach students that electric and magnetic fields can cause each other, but rather focus on charges and currents as the causal agents. In this paper I argue…

  7. Repeated Causal Decision Making

    ERIC Educational Resources Information Center

    Hagmayer, York; Meder, Bjorn

    2013-01-01

    Many of our decisions refer to actions that have a causal impact on the external environment. Such actions may not only allow for the mere learning of expected values or utilities but also for acquiring knowledge about the causal structure of our world. We used a repeated decision-making paradigm to examine what kind of knowledge people acquire in…

  8. Witnessing causal nonseparability

    NASA Astrophysics Data System (ADS)

    Araújo, Mateus; Branciard, Cyril; Costa, Fabio; Feix, Adrien; Giarmatzi, Christina; Brukner, Časlav

    2015-10-01

    Our common understanding of the physical world deeply relies on the notion that events are ordered with respect to some time parameter, with past events serving as causes for future ones. Nonetheless, it was recently found that it is possible to formulate quantum mechanics without any reference to a global time or causal structure. The resulting framework includes new kinds of quantum resources that allow performing tasks—in particular, the violation of causal inequalities—which are impossible for events ordered according to a global causal order. However, no physical implementation of such resources is known. Here we show that a recently demonstrated resource for quantum computation—the quantum switch—is a genuine example of ‘indefinite causal order’. We do this by introducing a new tool—the causal witness—which can detect the causal nonseparability of any quantum resource that is incompatible with a definite causal order. We show however that the quantum switch does not violate any causal inequality.

  9. Matching Theoretical Descriptions of Discourse and Practical Applications to Teaching: The Case of Causal Metatext.

    ERIC Educational Resources Information Center

    Moreno, Ana I.

    2003-01-01

    Demonstrates the need to bridge the gap between theoretical descriptions of discourse and type of language description that should be used in the English for academic purposes classroom in accordance with recent approaches to teaching a second language. Compares accounts of causal metatext from a sample of textbooks on academic writing to results…

  10. Agency, time, and causality

    PubMed Central

    Widlok, Thomas

    2014-01-01

    Cognitive Scientists interested in causal cognition increasingly search for evidence from non-Western Educational Industrial Rich Democratic people but find only very few cross-cultural studies that specifically target causal cognition. This article suggests how information about causality can be retrieved from ethnographic monographs, specifically from ethnographies that discuss agency and concepts of time. Many apparent cultural differences with regard to causal cognition dissolve when cultural extensions of agency and personhood to non-humans are taken into account. At the same time considerable variability remains when we include notions of time, linearity and sequence. The article focuses on ethnographic case studies from Africa but provides a more general perspective on the role of ethnography in research on the diversity and universality of causal cognition. PMID:25414683

  11. Integration of disease association and eQTL data using a Bayesian colocalisation approach highlights six candidate causal genes in immune-mediated diseases.

    PubMed

    Guo, Hui; Fortune, Mary D; Burren, Oliver S; Schofield, Ellen; Todd, John A; Wallace, Chris

    2015-06-15

    The genes and cells that mediate genetic associations identified through genome-wide association studies (GWAS) are only partially understood. Several studies that have investigated the genetic regulation of gene expression have shown that disease-associated variants are over-represented amongst expression quantitative trait loci (eQTL) variants. Evidence for colocalisation of eQTL and disease causal variants can suggest causal genes and cells for these genetic associations. Here, we used colocalisation analysis to investigate whether 595 genetic associations to ten immune-mediated diseases are consistent with a causal variant that regulates, in cis, gene expression in resting B cells, and in resting and stimulated monocytes. Previously published candidate causal genes were over-represented amongst genes exhibiting colocalisation (odds ratio > 1.5), and we identified evidence for colocalisation (posterior odds > 5) between cis eQTLs in at least one cell type and at least one disease for six genes: ADAM15, RGS1, CARD9, LTBR, CTSH and SYNGR1. We identified cell-specific effects, such as for CTSH, the expression of which in monocytes, but not in B cells, may mediate type 1 diabetes and narcolepsy associations in the chromosome 15q25.1 region. Our results demonstrate the utility of integrating genetic studies of disease and gene expression for highlighting causal genes and cell types. PMID:25743184

  12. Integration of disease association and eQTL data using a Bayesian colocalisation approach highlights six candidate causal genes in immune-mediated diseases

    PubMed Central

    Guo, Hui; Fortune, Mary D.; Burren, Oliver S.; Schofield, Ellen; Todd, John A.; Wallace, Chris

    2015-01-01

    The genes and cells that mediate genetic associations identified through genome-wide association studies (GWAS) are only partially understood. Several studies that have investigated the genetic regulation of gene expression have shown that disease-associated variants are over-represented amongst expression quantitative trait loci (eQTL) variants. Evidence for colocalisation of eQTL and disease causal variants can suggest causal genes and cells for these genetic associations. Here, we used colocalisation analysis to investigate whether 595 genetic associations to ten immune-mediated diseases are consistent with a causal variant that regulates, in cis, gene expression in resting B cells, and in resting and stimulated monocytes. Previously published candidate causal genes were over-represented amongst genes exhibiting colocalisation (odds ratio > 1.5), and we identified evidence for colocalisation (posterior odds > 5) between cis eQTLs in at least one cell type and at least one disease for six genes: ADAM15, RGS1, CARD9, LTBR, CTSH and SYNGR1. We identified cell-specific effects, such as for CTSH, the expression of which in monocytes, but not in B cells, may mediate type 1 diabetes and narcolepsy associations in the chromosome 15q25.1 region. Our results demonstrate the utility of integrating genetic studies of disease and gene expression for highlighting causal genes and cell types. PMID:25743184

  13. No-Pass Zone: Multidisciplinary Approach to Responding to Patient Needs.

    PubMed

    Lee, Tracy L; Crouse, Marlene; Gipson, Kelly

    2016-01-01

    A nurse's need to juggle multiple priorities often leads to delays in responses to patient call lights, which may result in the patient's needs not being met quickly. Low patient satisfaction scores related to hospital staff responding to patient needs created urgency for this system to implement the No-Pass Zone, a multidisciplinary team approach to responding to call lights. A successful implementation of this intervention resulted in patients' needs being met more quickly as indicated by improved Hospital Consumer Assessment of Health Care Providers and Systems performance postimplementation. PMID:26845421

  14. Analysing connectivity with Granger causality and dynamic causal modelling

    PubMed Central

    Friston, Karl; Moran, Rosalyn; Seth, Anil K

    2013-01-01

    This review considers state-of-the-art analyses of functional integration in neuronal macrocircuits. We focus on detecting and estimating directed connectivity in neuronal networks using Granger causality (GC) and dynamic causal modelling (DCM). These approaches are considered in the context of functional segregation and integration and — within functional integration — the distinction between functional and effective connectivity. We review recent developments that have enjoyed a rapid uptake in the discovery and quantification of functional brain architectures. GC and DCM have distinct and complementary ambitions that are usefully considered in relation to the detection of functional connectivity and the identification of models of effective connectivity. We highlight the basic ideas upon which they are grounded, provide a comparative evaluation and point to some outstanding issues. PMID:23265964

  15. Causal Networks or Causal Islands? The Representation of Mechanisms and the Transitivity of Causal Judgment

    ERIC Educational Resources Information Center

    Johnson, Samuel G. B.; Ahn, Woo-kyoung

    2015-01-01

    Knowledge of mechanisms is critical for causal reasoning. We contrasted two possible organizations of causal knowledge--an interconnected causal "network," where events are causally connected without any boundaries delineating discrete mechanisms; or a set of disparate mechanisms--causal "islands"--such that events in different…

  16. Needs assessments in palliative care: an appraisal of definitions and approaches used.

    PubMed

    Higginson, Irene J; Hart, Sam; Koffman, Jonathan; Selman, Lucy; Harding, Richard

    2007-05-01

    We report a systematic appraisal of definitions and approaches to needs assessment in palliative care. Electronic databases were searched, and relevant individuals and organizations were contacted to identify needs assessments in palliative care. Over 200 articles were identified giving general information on needs assessment, and 77 articles comprised palliative care-related needs assessment reports. The reports originated from Africa (37), Australia (1), Europe (including former central/eastern European states) (35), USA (1), Latin America (5), and Asia (7). Two underpinning definitions of need were identified, that of Maslow from the field of psychology, and that of Bradshaw from sociology. However, in conducting needs assessments, these definitions were operationalized, and here the National Health Service Executive definition of need as "the ability to benefit from health care" is helpful. We identified three main categories of approach to needs assessment--epidemiological, corporate, and comparative--that can be used in combination. Careful consideration must be paid to any needs assessment data to ensure that the assessment is implemented. PMID:17482037

  17. Warp drive and causality

    NASA Astrophysics Data System (ADS)

    Everett, Allen E.

    1996-06-01

    Alcubierre recently exhibited a spacetime which, within the framework of general relativity, allows travel at superluminal speeds if matter with a negative energy density can exist, and conjectured that it should be possible to use similar techniques to construct a theory containing closed causal loops and, thus, travel backwards in time. We verify this conjecture by exhibiting a simple modification of Alcubierre's model, requiring no additional assumptions, in which causal loops are possible. We also note that this mechanism for generating causal loops differs in essential ways from that discovered by Gott involving cosmic strings.

  18. Two-step epigenetic Mendelian randomization: a strategy for establishing the causal role of epigenetic processes in pathways to disease

    PubMed Central

    Relton, Caroline L; Davey Smith, George

    2012-01-01

    The burgeoning interest in the field of epigenetics has precipitated the need to develop approaches to strengthen causal inference when considering the role of epigenetic mediators of environmental exposures on disease risk. Epigenetic markers, like any other molecular biomarker, are vulnerable to confounding and reverse causation. Here, we present a strategy, based on the well-established framework of Mendelian randomization, to interrogate the causal relationships between exposure, DNA methylation and outcome. The two-step approach first uses a genetic proxy for the exposure of interest to assess the causal relationship between exposure and methylation. A second step then utilizes a genetic proxy for DNA methylation to interrogate the causal relationship between DNA methylation and outcome. The rationale, origins, methodology, advantages and limitations of this novel strategy are presented. PMID:22422451

  19. Identifying causal variants at loci with multiple signals of association.

    PubMed

    Hormozdiari, Farhad; Kostem, Emrah; Kang, Eun Yong; Pasaniuc, Bogdan; Eskin, Eleazar

    2014-10-01

    Although genome-wide association studies have successfully identified thousands of risk loci for complex traits, only a handful of the biologically causal variants, responsible for association at these loci, have been successfully identified. Current statistical methods for identifying causal variants at risk loci either use the strength of the association signal in an iterative conditioning framework or estimate probabilities for variants to be causal. A main drawback of existing methods is that they rely on the simplifying assumption of a single causal variant at each risk locus, which is typically invalid at many risk loci. In this work, we propose a new statistical framework that allows for the possibility of an arbitrary number of causal variants when estimating the posterior probability of a variant being causal. A direct benefit of our approach is that we predict a set of variants for each locus that under reasonable assumptions will contain all of the true causal variants with a high confidence level (e.g., 95%) even when the locus contains multiple causal variants. We use simulations to show that our approach provides 20-50% improvement in our ability to identify the causal variants compared to the existing methods at loci harboring multiple causal variants. We validate our approach using empirical data from an expression QTL study of CHI3L2 to identify new causal variants that affect gene expression at this locus. CAVIAR is publicly available online at http://genetics.cs.ucla.edu/caviar/. PMID:25104515

  20. Identifying Causal Variants at Loci with Multiple Signals of Association

    PubMed Central

    Hormozdiari, Farhad; Kostem, Emrah; Kang, Eun Yong; Pasaniuc, Bogdan; Eskin, Eleazar

    2014-01-01

    Although genome-wide association studies have successfully identified thousands of risk loci for complex traits, only a handful of the biologically causal variants, responsible for association at these loci, have been successfully identified. Current statistical methods for identifying causal variants at risk loci either use the strength of the association signal in an iterative conditioning framework or estimate probabilities for variants to be causal. A main drawback of existing methods is that they rely on the simplifying assumption of a single causal variant at each risk locus, which is typically invalid at many risk loci. In this work, we propose a new statistical framework that allows for the possibility of an arbitrary number of causal variants when estimating the posterior probability of a variant being causal. A direct benefit of our approach is that we predict a set of variants for each locus that under reasonable assumptions will contain all of the true causal variants with a high confidence level (e.g., 95%) even when the locus contains multiple causal variants. We use simulations to show that our approach provides 20–50% improvement in our ability to identify the causal variants compared to the existing methods at loci harboring multiple causal variants. We validate our approach using empirical data from an expression QTL study of CHI3L2 to identify new causal variants that affect gene expression at this locus. CAVIAR is publicly available online at http://genetics.cs.ucla.edu/caviar/. PMID:25104515

  1. A quality approach for conducting training needs assessments in the Ministry of Health, State of Bahrain.

    PubMed

    Benjamin, S; al-Darazi, F

    2000-01-01

    In health care organizations around the world, Training Needs Assessments (TNAs) have generally followed a professions-based approach. For example, the training needs of doctors, nurses, each allied health profession, and distinct support staff have been analyzed separately--individualized TNAs conducted for each speciality and functional area. Although a professions-based TNA model can provide useful information to human resource development (HRD) professionals, there are two major drawbacks: (1) it is possible that important training needs might be overlooked because of lack of information sharing among professions and (2) such an approach does not encourage an interdisciplinary, team orientation to service provision. This paper proposes an improved method of conceptualizing TNAs, using an approach that builds on the quality management literature (TQM, CQI, etc.) which stresses the importance of customer- and service-orientations to organizing and measuring organizational and individual performance. PMID:11214453

  2. Causal structures in Gauss-Bonnet gravity

    NASA Astrophysics Data System (ADS)

    Izumi, Keisuke

    2014-08-01

    We analyze causal structures in Gauss-Bonnet gravity. It is known that Gauss-Bonnet gravity potentially has superluminal propagation of gravitons due to its noncanonical kinetic terms. In a theory with superluminal modes, an analysis of causality based on null curves makes no sense, and thus, we need to analyze them in a different way. In this paper, using the method of the characteristics, we analyze the causal structure in Gauss-Bonnet gravity. We have the result that, on a Killing horizon, gravitons can propagate in the null direction tangent to the Killing horizon. Therefore, a Killing horizon can be a causal edge as in the case of general relativity; i.e. a Killing horizon is the "event horizon" in the sense of causality. We also analyze causal structures on nonstationary solutions with (D-2)-dimensional maximal symmetry, including spherically symmetric and flat spaces. If the geometrical null energy condition, RABNANB≥0 for any null vector NA, is satisfied, the radial velocity of gravitons must be less than or equal to that of light. However, if the geometrical null energy condition is violated, gravitons can propagate faster than light. Hence, on an evaporating black hole where the geometrical null energy condition is expected not to hold, classical gravitons can escape from the "black hole" defined with null curves. That is, the causal structures become nontrivial. It may be one of the possible solutions for the information loss paradox of evaporating black holes.

  3. Student (dis)engagement and need-supportive teaching behavior: a multi-informant and multilevel approach.

    PubMed

    Van den Berghe, Lynn; Tallir, Isabel B; Cardon, Greet; Aelterman, Nathalie; Haerens, Leen

    2015-08-01

    Starting from self-determination theory, we explored whether student engagement/disengagement relates to teachers' need support and whether this relationship is moderated by teachers' causality orientations. A sample of 2004 students situated in 127 classes taught by 33 physical education teachers participated in the study. Both teachers and students reported on students' (dis)engagement, allowing investigation of the proposed relationships both at the student and teacher level. Most of the variance in need support was at the student level, but there was also between-teacher and between-class variance in need support. Engagement related to more need support, but only at the student level. In total, few moderation effects were found. Teachers with a relatively low controlled orientation were more need supportive when perceiving their students as emotionally and behaviorally engaged. By making teachers aware of these dynamics, automatic responses to student engagement can be better thought out. Recommendations for future research are discussed. PMID:26442767

  4. Assessing prosthodontic dental treatment needs in older adults in Thailand: normative vs. sociodental approaches.

    PubMed

    Srisilapanan, Patcharawan; Korwanich, Narumanas; Sheiham, Aubrey

    2003-01-01

    The authors compared the estimated prosthodontic treatment needs of edentulous older adults when using normative and sociodental approaches. This cross-sectional study involved a non-random sample of 158 edentulous adults, aged 60 to 74 years, who were living independently in metropolitan Chiang Mai, Thailand. Each subject was given an oral examination and was interviewed. The dental questionnaire and the clinical criteria were adapted from the National Diet and Nutritional Survey for People Aged 65 and Older and included the Oral Impacts on Daily Performances sociodental indicator. Of the 158 subjects, we found using a normative assessment that 79.7% had a treatment need for complete dentures; 60.5% of those adults had impact-related treatment needs. Estimated treatment need dropped by about 40% when subjects were assessed using the sociodental approach. We concluded that large reductions in normative need estimates for complete dentures were apparent using a sociodental approach to assess prosthodontic dental treatment needs of older people. PMID:14765891

  5. Career Education for Handicapped Students: A Suggested Approach. Technical Assistance Services: Illinois Special Needs Populations.

    ERIC Educational Resources Information Center

    Miller, Sidney R.; And Others

    This monograph describes a suggested approach to career education for handicapped students that focuses on two aspects of the career development process, career exploration and development of an academic program reflecting vocational needs. Discussed in the section on career exploration are career goals, the teacher-counselor role, individual…

  6. The Need for a Culturally Relevant Approach to Gifted Education: The Case of Cyprus

    ERIC Educational Resources Information Center

    Ieridou, Alexandra N.

    2013-01-01

    This article presents an overview of the status of gifted education in Cyprus and argues for the need for a culturally relevant approach. First, the history of education in Cyprus is briefly reviewed. Then, past unsuccessful efforts to provide education for academically advanced students in the public elementary schools are critically examined.…

  7. Inventorying Student Needs and Perceptions of Available Help: A Simplified Approach.

    ERIC Educational Resources Information Center

    Beeler, Kent D.

    This paper describes the Student Perceptions Survey (SPS), a simplified, pragmatic, and nontechnical approach to inventorying student needs and student perceptions of available help on the campus. A literature review on assessing institutional environments and the developmental tasks of college age students is provided. The SPS incorporates the…

  8. The Relationship among Student Basic Need Satisfaction, Approaches to Learning, Reporting of Avoidance Strategies and Achievement

    ERIC Educational Resources Information Center

    Betoret, Fernando Domenech; Artiga, Amparo Gomez

    2011-01-01

    Introduction: This study examines the relationship between student basic need satisfaction (autonomy, competence, relatedness and belonging), their reporting of approaches to learning (deep and surface), their reporting of avoidance strategies (avoidance of effort and challenge, avoidance of help seeking and preference to avoid novelty) and…

  9. Effective connectivity: Influence, causality and biophysical modeling

    PubMed Central

    Valdes-Sosa, Pedro A.; Roebroeck, Alard; Daunizeau, Jean; Friston, Karl

    2011-01-01

    This is the final paper in a Comments and Controversies series dedicated to “The identification of interacting networks in the brain using fMRI: Model selection, causality and deconvolution”. We argue that discovering effective connectivity depends critically on state-space models with biophysically informed observation and state equations. These models have to be endowed with priors on unknown parameters and afford checks for model Identifiability. We consider the similarities and differences among Dynamic Causal Modeling, Granger Causal Modeling and other approaches. We establish links between past and current statistical causal modeling, in terms of Bayesian dependency graphs and Wiener–Akaike–Granger–Schweder influence measures. We show that some of the challenges faced in this field have promising solutions and speculate on future developments. PMID:21477655

  10. Dimensional Reduction in Causal Set Gravity

    NASA Astrophysics Data System (ADS)

    Carlip, Steven

    2016-03-01

    Several different approaches to quantum gravity indicate that the effective dimension of spacetime falls to approximately two at very short distances. I provide evidence for similar behavior in the causal set approach to quantum gravity. Supported in part by Department of Energy Grant DE-FG02-91ER40674.

  11. Causality discovery technology

    NASA Astrophysics Data System (ADS)

    Chen, M.; Ertl, T.; Jirotka, M.; Trefethen, A.; Schmidt, A.; Coecke, B.; Bañares-Alcántara, R.

    2012-11-01

    Causality is the fabric of our dynamic world. We all make frequent attempts to reason causation relationships of everyday events (e.g., what was the cause of my headache, or what has upset Alice?). We attempt to manage causality all the time through planning and scheduling. The greatest scientific discoveries are usually about causality (e.g., Newton found the cause for an apple to fall, and Darwin discovered natural selection). Meanwhile, we continue to seek a comprehensive understanding about the causes of numerous complex phenomena, such as social divisions, economic crisis, global warming, home-grown terrorism, etc. Humans analyse and reason causality based on observation, experimentation and acquired a priori knowledge. Today's technologies enable us to make observations and carry out experiments in an unprecedented scale that has created data mountains everywhere. Whereas there are exciting opportunities to discover new causation relationships, there are also unparalleled challenges to benefit from such data mountains. In this article, we present a case for developing a new piece of ICT, called Causality Discovery Technology. We reason about the necessity, feasibility and potential impact of such a technology.

  12. Causal conditionals and counterfactuals

    PubMed Central

    Frosch, Caren A.; Byrne, Ruth M.J.

    2012-01-01

    Causal counterfactuals e.g., ‘if the ignition key had been turned then the car would have started’ and causal conditionals e.g., ‘if the ignition key was turned then the car started’ are understood by thinking about multiple possibilities of different sorts, as shown in six experiments using converging evidence from three different types of measures. Experiments 1a and 1b showed that conditionals that comprise enabling causes, e.g., ‘if the ignition key was turned then the car started’ primed people to read quickly conjunctions referring to the possibility of the enabler occurring without the outcome, e.g., ‘the ignition key was turned and the car did not start’. Experiments 2a and 2b showed that people paraphrased causal conditionals by using causal or temporal connectives (because, when), whereas they paraphrased causal counterfactuals by using subjunctive constructions (had…would have). Experiments 3a and 3b showed that people made different inferences from counterfactuals presented with enabling conditions compared to none. The implications of the results for alternative theories of conditionals are discussed. PMID:22858874

  13. Meeting water needs for sustainable development: an overview of approaches, measures and data sources

    NASA Astrophysics Data System (ADS)

    Lissner, Tabea; Reusser, Dominik E.; Sullivan, Caroline A.; Kropp, Jürgen P.

    2013-04-01

    An essential part of a global transition towards sustainability is the Millennium Development Goals (MDG), providing a blueprint of goals to meet human needs. Water is an essential resource in itself, but also a vital factor of production for food, energy and other industrial products. Access to sufficient water has only recently been recognized as a human right. One central MDG is halving the population without access to safe drinking water and sanitation. To adequately assess the state of development and the potential for a transition towards sustainability, consistent and meaningful measures of water availability and adequate access are thus fundamental. Much work has been done to identify thresholds and definitions to measure water scarcity. This includes some work on defining basic water needs of different sectors. A range of data and approaches has been made available from a variety of sources, but all of these approaches differ in their underlying assumptions, the nature of the data used, and consequently in the final results. We review and compare approaches, methods and data sources on human water use and human water needs. This data review enables identifying levels of consumption in different countries and different sectors. Further comparison is made between actual water needs (based on human and ecological requirements), and recognised levels of water abstraction. The results of our review highlight the differences between different accounts of water use and needs, and reflect the importance of standardised approaches to data definitions and measurements, making studies more comparable across space and time. The comparison of different use and allocation patterns in countries enables levels of water use to be identified which allow for an adequate level of human wellbeing to be maintained within sustainable water abstraction limits. Recommendations are provided of how data can be defined more clearly to make comparisons of water use more meaningful and

  14. Health needs assessment in primary care: the evolution of a practical public health approach.

    PubMed

    Kilduff, A; McKeown, K; Crowther, A

    1998-05-01

    The purpose of the paper is to place health needs assessment in its primary care context. This is a dynamic context where changes in policies, staff roles and patient expectations have all to be considered. Given this complexity and the variations between practices, it is necessary to help primary health care teams (PHCTs) to understand their stage of development and how this will directly affect any health needs assessment. The technical and methodological aspects of health needs assessment have been explored and described by others, and that work will not be duplicated here. This paper reviews the health needs assessment (HNA) work of the Ribblesdale Total Purchasing Project (RTPP) and then sets this review against the political, organisational, professional and practical pressures that currently confront primary care. Out of this analysis emerges a diagnostic and development tool which links together, and emphasises the intimate relationships between, five stages of development needed for effective primary care-oriented health needs assessment work. The emphasis is on understanding the place of health needs assessment within the general processes and systems of the primary health care team. The paper concludes by suggesting ways in which public health practitioners and specialists might approach the task of supporting and influencing the evolution of the recently proposed Primary Care Groups and Primary Care Trusts. The overall intention of the article is to stimulate debate and action. PMID:9629025

  15. High school teachers' perspectives on effective approaches for teaching biology to students with special needs

    NASA Astrophysics Data System (ADS)

    Kos, Agnieszka

    The demands of national educational reforms require high school biology teachers to provide high quality instruction to students with and without special needs. The reforms, however, do not provide teachers with adequate teaching strategies to meet the needs of all students in the same context. The purpose of this grounded theory study was to understand high school biology teachers' perspectives, practices, and challenges in relation to teaching students with special needs. This approach was used to develop a substantive model for high school biology teachers who are challenged with teaching students with and without special needs. Data were collected via in-depth interviews with 15 high school teachers in a Midwestern school district. The data were analyzed using open coding, axial coding, and selective coding procedures in accordance with the grounded theory approach. Essential model components included skills and training for teachers, classroom management strategies, teaching strategies, and student skills. The emergent substantive theory indicated that that teacher preparation and acquired skills greatly influence the effectiveness of inclusion implementation. Key findings also indicated the importance of using of a variety of instructional strategies and classroom management strategies that address students' special needs and their learning styles. This study contributes to social change by providing a model for teaching students and effectively implementing inclusion in regular science classrooms. Following further study, this model may be used to support teacher professional development and improve teaching practices that in turn may improve science literacy supported by the national educational reforms.

  16. Ensemble of Causal Trees

    NASA Astrophysics Data System (ADS)

    Bialas, Piotr

    2003-10-01

    We discuss the geometry of trees endowed with a causal structure using the conventional framework of equilibrium statistical mechanics. We show how this ensemble is related to popular growing network models. In particular we demonstrate that on a class of afine attachment kernels the two models are identical but they can differ substantially for other choice of weights. We show that causal trees exhibit condensation even for asymptotically linear kernels. We derive general formulae describing the degree distribution, the ancestor--descendant correlation and the probability that a randomly chosen node lives at a given geodesic distance from the root. It is shown that the Hausdorff dimension dH of the causal networks is generically infinite.

  17. Physical Activity and Movement Proficiency: The Need for a Biocultural Approach.

    PubMed

    Malina, Robert M; Cumming, Sean P; Coelho E Silva, Manuel J

    2016-05-01

    "Gaps in Our Knowledge" are discussed in the context of the need to integrate biological and behavioral factors in a biocultural approach to physical activity and movement proficiency. Specific issues considered include outdoor play, organized and informal activity, biological maturation, tracking of activity, development of movement proficiency, and individual differences. Studies considered are largely based on youth in economically better-off, developed countries in the western culture context. There is a need to extend studies of physical activity and movement proficiency to different cultural contexts. PMID:27137170

  18. Causal networks or causal islands? The representation of mechanisms and the transitivity of causal judgment

    PubMed Central

    Johnson, Samuel G. B.; Ahn, Woo-kyoung

    2014-01-01

    Knowledge of mechanisms is critical for causal reasoning. We contrasted two possible organizations of causal knowledge—an interconnected causal network, where events are causally connected without any boundaries delineating discrete mechanisms; or a set of disparate mechanisms—causal islands—such that events in different mechanisms are not thought to be related even when they belong to the same causal chain. To distinguish these possibilities, we used causal transitivity—the inference given A causes B and B causes C that A causes C. Specifically, causal chains schematized as one chunk or mechanism in semantic memory (e.g., exercising, becoming thirsty, drinking water) led to transitive causal judgments. On the other hand, chains schematized as multiple chunks (e.g., having sex, becoming pregnant, becoming nauseous) led to intransitive judgments despite strong intermediate links (Experiments 1–3). Normative accounts of causal intransitivity could not explain these intransitive judgments (Experiments 4–5). PMID:25556901

  19. Clinical development of gene therapy needs a tailored approach: a regulatory perspective from the European Union.

    PubMed

    Narayanan, Gopalan; Cossu, Giulio; Galli, Maria Cristina; Flory, Egbert; Ovelgonne, Hans; Salmikangas, Paula; Schneider, Christian K; Trouvin, Jean-Hugues

    2014-03-01

    Gene therapy is a rapidly evolving field that needs an integrated approach, as acknowledged in the concept article on the revision of the guideline on gene transfer medicinal products. The first gene therapy application for marketing authorization was approved in the International Conference on Harmonisation (ICH) region in 2012, the product being Alipogene tiparvovec. The regulatory process for this product has been commented on extensively, highlighting the challenges posed by such a novel technology. Here, as current or previous members of the Committee for Advanced Therapies, we share our perspectives and views on gene therapy as a treatment modality based on current common understanding and regulatory experience of gene therapy products in the European Union to date. It is our view that a tailored approach is needed for a given gene therapy product in order to achieve successful marketing authorization. PMID:24649836

  20. Clinical development of Gene therapy needs a tailored approach: A regulatory perspective from the EU.

    PubMed

    Narayanan, Gopalan; Salmikangas, Paula; Schneider, Christian K; Galli, Maria Cristina; Trouvin, Jean-Hugues; Flory, Egbert; Cossu, Giulio; Ovelgonne, Hans

    2014-02-18

    Gene therapy is a rapidly evolving field, which needs an integrated approach, as acknowledged in the Concept paper on the revision of the guideline on gene transfer medicinal products (Concept paper, EMA, 2009). The first gene therapy application for marketing authorisation was approved in the ICH region in 2012, the product being Alipogene tiparvovec (http, summary for the public, 2012). The regulatory process for this product has been commented on extensively, highlighting the challenges posed by such a novel technology (English, 2011; Flemming, 2012; Melchiorri et al, 2013; Miller, 2012). Here, as current or previous members of the Committee for Advanced Therapies (CAT), we share our perspectives and views on gene therapy as a treatment modality based on current common understanding and regulatory experience of gene therapy products in the EU to date. It is our view that a tailored approach is needed for a given gene therapy product in order to achieve successful Marketing Authorisation. PMID:24547991

  1. Management and medicine: why we need a new approach to the relationship.

    PubMed

    Kuhlmann, Ellen; von Knorring, Mia

    2014-02-25

    New Public Management has affected the relationship between corporate managerialism and professional modes of governing hospitals. While doctors' increasing involvement in management may have positive effects on health care, hospital governance, health care policies and medical education have largely failed to support this change. There is a need for new policies and approaches to support the changing connections between medicine and management that abandons both the military discourse of 'wars' and 'battlefields' and the new rhetoric of 'clinical leadership'. PMID:24569982

  2. On the Brink of Shifting Paradigms, Molecular Systems Engineering Ethics Needs to Take a Proactive Approach.

    PubMed

    Heidari, Raheleh; Elger, Bernice S; Stutzki, Ralf

    2016-01-01

    Molecular Systems Engineering (MSE) is a paradigm shift in both engineering and life sciences. While the field is still in its infancy the perspectives of MSE in revolutionising technology is promising. MSE will offer a wide range of applications in clinical, biotechnological and engineering fields while simultaneously posing serious questions on the ethical and societal aspects of such technology. The moral and societal aspects of MSE need systematic investigation from scientific and social perspectives. In a democratic setting, the societal outcomes of MSE's cutting-edge technology need to be consulted and influenced by society itself. For this purpose MSE needs inclusive public engagement strategies that bring together the public, ethicists, scientists and policy makers for optimum flow of information that maximizes the impact of public engagement. In this report we present an MSE consortium and its ethics framework for establishing a proactive approach in the study of the ethics of MSE technology. PMID:27363376

  3. There is a need for a multidisciplinary approach to patient safety.

    PubMed

    Taneva, Svetlena

    2013-01-01

    In the lead paper, Zimmerman et al. explore the role of problem and solution ownership in solution adoption by front-line healthcare staff. The front-line ownership (FLO) approach suggested by the authors proposes a shift in leadership style such that managers act as enablers of patient safety improvement efforts by front-line staff (i.e., a bottom-up management style). From a systems perspective, it would be necessary to examine contributing factors to patient safety problems, including process, workflow, task requirements etc., in order to effectively utilize a solution-oriented approach such as FLO. These factors would be difficult to identify by clinical staff alone. There is a need for a multidisciplinary approach to patient safety management in healthcare. PMID:23803351

  4. Causality: Physics and Philosophy

    ERIC Educational Resources Information Center

    Chatterjee, Atanu

    2013-01-01

    Nature is a complex causal network exhibiting diverse forms and species. These forms or rather systems are physically open, structurally complex and naturally adaptive. They interact with the surrounding media by operating a positive-feedback loop through which, they adapt, organize and self-organize themselves in response to the ever-changing…

  5. The Causal Asymmetry

    ERIC Educational Resources Information Center

    White, Peter A.

    2006-01-01

    It is hypothesized that there is a pervasive and fundamental bias in humans' understanding of physical causation: Once the roles of cause and effect are assigned to objects in interactions, people tend to overestimate the strength and importance of the causal object and underestimate that of the effect object in bringing about the outcome. This…

  6. Causal essentialism in kinds.

    PubMed

    Ahn, Woo-kyoung; Taylor, Eric G; Kato, Daniel; Marsh, Jessecae K; Bloom, Paul

    2013-06-01

    The current study examines causal essentialism, derived from psychological essentialism of concepts. We examine whether people believe that members of a category share some underlying essence that is both necessary and sufficient for category membership and that also causes surface features. The main claim is that causal essentialism is restricted to categories that correspond to our intuitive notions of existing kinds and hence is more attenuated for categories that are based on arbitrary criteria. Experiments 1 and 3 found that people overtly endorse causal essences in nonarbitrary kinds but are less likely to do so for arbitrary categories. Experiments 2 and 4 found that people were more willing to generalize a member's known causal relations (or lack thereof) when dealing with a kind than when dealing with an arbitrary category. These differences between kinds and arbitrary categories were found across various domains-not only for categories of living things, but also for artefacts. These findings have certain real-world implications, including how people make sense of mental disorders that are treated as real kinds. PMID:23098315

  7. Causal Premise Semantics

    ERIC Educational Resources Information Center

    Kaufmann, Stefan

    2013-01-01

    The rise of causality and the attendant graph-theoretic modeling tools in the study of counterfactual reasoning has had resounding effects in many areas of cognitive science, but it has thus far not permeated the mainstream in linguistic theory to a comparable degree. In this study I show that a version of the predominant framework for the formal…

  8. Causal Responsibility and Counterfactuals

    ERIC Educational Resources Information Center

    Lagnado, David A.; Gerstenberg, Tobias; Zultan, Ro'i

    2013-01-01

    How do people attribute responsibility in situations where the contributions of multiple agents combine to produce a joint outcome? The prevalence of over-determination in such cases makes this a difficult problem for counterfactual theories of causal responsibility. In this article, we explore a general framework for assigning responsibility in…

  9. Evaluating Causal Models.

    ERIC Educational Resources Information Center

    Watt, James H., Jr.

    Pointing out that linear causal models can organize the interrelationships of a large number of variables, this paper contends that such models are particularly useful to mass communication research, which must by necessity deal with complex systems of variables. The paper first outlines briefly the philosophical requirements for establishing a…

  10. Causal Mediation Analyses for Randomized Trials.

    PubMed

    Lynch, Kevin G; Cary, Mark; Gallop, Robert; Ten Have, Thomas R

    2008-01-01

    In the context of randomized intervention trials, we describe causal methods for analyzing how post-randomization factors constitute the process through which randomized baseline interventions act on outcomes. Traditionally, such mediation analyses have been undertaken with great caution, because they assume that the mediating factor is also randomly assigned to individuals in addition to the randomized baseline intervention (i.e., sequential ignorability). Because the mediating factors are typically not randomized, such analyses are unprotected from unmeasured confounders that may lead to biased inference. We review several causal approaches that attempt to reduce such bias without assuming that the mediating factor is randomized. However, these causal approaches require certain interaction assumptions that may be assessed if there is enough treatment heterogeneity with respect to the mediator. We describe available estimation procedures in the context of several examples from the literature and provide resources for software code. PMID:19484136

  11. Use of a Mendelian randomization approach to assess the causal relation of gamma-Glutamyltransferase with blood pressure and serum insulin levels.

    PubMed

    Conen, David; Vollenweider, Peter; Rousson, Valentin; Marques-Vidal, Pedro; Paccaud, Fred; Waeber, Gérard; Bochud, Murielle

    2010-12-15

    Elevated levels of γ-glutamyltransferase (GGT) have been associated with elevated blood pressure (BP) and diabetes. However, the causality of these relations has not been addressed. The authors performed a cross-sectional analysis (2003-2006) among 4,360 participants from the population-based Cohorte Lausannoise (CoLaus) Study (Lausanne, Switzerland). The rs2017869 variant of the γ-glutamyltransferase 1 (GGT1) gene, which explained 1.6% of the variance in GGT levels, was used as an instrument for Mendelian randomization (MR). Sex-specific GGT quartiles were strongly associated with both systolic and diastolic BP (all P's < 0.0001). After multivariable adjustment, these relations were attenuated but remained significant. Using MR, the authors observed no positive association of GGT with BP (systolic: β -5.68, 95% confidence interval (CI): -11.51, 0.16 (P = 0.06); diastolic: β = -2.24, 95% CI: -5.98, 1.49 (P = 0.24)). The association of GGT with insulin was also attenuated after multivariable adjustment but persisted in the fully adjusted model (β = 0.07, 95% CI: 0.04, 0.09; P < 0.0001). Using MR, the authors also observed a positive association of GGT with insulin (β = 0.19, 95% CI: 0.01, 0.37; P = 0.04). In conclusion, the authors found evidence for a direct causal relation of GGT with fasting insulin but not with BP. PMID:21044991

  12. A social impact assessment of the floodwater spreading project on the Gareh-Bygone plain in Iran: A causal comparative approach

    SciTech Connect

    Ahmadvand, Mostafa Karami, Ezatollah

    2009-02-15

    The purpose of this study was to explore the social impacts of the floodwater spreading project (FWSP) on the Gareh-Bygone plain, Iran. The study was in the form of a causal comparative design, and a triangulation technique was used to collect data including the use of survey data, archival data, and a participatory rural appraisal (PRA). The causal comparative method requires a comparison of villages with and without the FWSP. Therefore, a survey was conducted using stratified random sampling to select 202 households in villages with and without FWSP in the plain. Significant differences were found between the respondents in villages with and without FWSP with regard to social impact criteria. In spite of the project had negative impact on perceived wellbeing, social capital, social structure development; it had positive impact on quality of life, rural and agricultural economic conditions, and conservation of community resources. However, no significant difference was found between women and men regarding the SIA of FWSP in Gareh-Bygone plain. Analysis of the archival data and PRA techniques supported the survey results and demonstrated that the project improved environmental criteria and deteriorated social dimensions.

  13. Causal Status and Coherence in Causal-Based Categorization

    ERIC Educational Resources Information Center

    Rehder, Bob; Kim, ShinWoo

    2010-01-01

    Research has documented two effects of interfeature causal knowledge on classification. A "causal status effect" occurs when features that are causes are more important to category membership than their effects. A "coherence effect" occurs when combinations of features that are consistent with causal laws provide additional evidence of category…

  14. Reference Data Layers for Earth and Environmental Science: History, Frameworks, Science Needs, Approaches, and New Technologies

    NASA Astrophysics Data System (ADS)

    Lenhardt, W. C.

    2015-12-01

    Global Mapping Project, Web-enabled Landsat Data (WELD), International Satellite Land Surface Climatology Project (ISLSCP), hydrology, solid earth dynamics, sedimentary geology, climate modeling, integrated assessments and so on all have needs for or have worked to develop consistently integrated data layers for Earth and environmental science. This paper will present an overview of an abstract notion of data layers of this types, what we are referring to as reference data layers for Earth and environmental science, highlight some historical examples, and delve into new approaches. The concept of reference data layers in this context combines data availability, cyberinfrastructure and data science, as well as domain science drivers. We argue that current advances in cyberinfrastructure such as iPython notebooks and integrated science processing environments such as iPlant's Discovery Environment coupled with vast arrays of new data sources warrant another look at the how to create, maintain, and provide reference data layers. The goal is to provide a context for understanding science needs for reference data layers to conduct their research. In addition, to the topics described above this presentation will also outline some of the challenges to and present some ideas for new approaches to addressing these needs. Promoting the idea of reference data layers is relevant to a number of existing related activities such as EarthCube, RDA, ESIP, the nascent NSF Regional Big Data Innovation Hubs and others.

  15. Towards Current Profile Control in ITER: Potential Approaches and Research Needs

    NASA Astrophysics Data System (ADS)

    Schuster, E.; Barton, J. E.; Wehner, W. P.

    2014-10-01

    Many challenging plasma control problems still need to be addressed in order for the ITER Plasma Control System (PCS) to be able to successfully achieve the ITER project goals. For instance, setting up a suitable toroidal current density profile is key for one possible advanced scenario characterized by noninductive sustainment of the plasma current and steady-state operation. The nonlinearity and high dimensionality exhibited by the plasma demand a model-based current-profile control synthesis procedure that can accommodate this complexity through embedding the known physics within the design. The development of a model capturing the dynamics of the plasma relevant for control design enables not only the design of feedback controllers for regulation or tracking but also the design of optimal feedforward controllers for a systematic model-based approach to scenario planning, the design of state estimators for a reliable real-time reconstruction of the plasma internal profiles based on limited and noisy diagnostics, and the development of a fast predictive simulation code for closed-loop performance evaluation before implementation. Progress towards control-oriented modeling of the current profile evolution and associated control design has been reported following both data-driven and first-principles-driven approaches. An overview of these two approaches will be provided, as well as a discussion on research needs associated with each one of the model applications described above. Supported by the US Department of Energy under DE-SC0001334 and DE-SC0010661.

  16. The development of causal categorization.

    PubMed

    Hayes, Brett K; Rehder, Bob

    2012-08-01

    Two experiments examined the impact of causal relations between features on categorization in 5- to 6-year-old children and adults. Participants learned artificial categories containing instances with causally related features and noncausal features. They then selected the most likely category member from a series of novel test pairs. Classification patterns and logistic regression were used to diagnose the presence of independent effects of causal coherence, causal status, and relational centrality. Adult classification was driven primarily by coherence when causal links were deterministic (Experiment 1) but showed additional influences of causal status when links were probabilistic (Experiment 2). Children's classification was based primarily on causal coherence in both cases. There was no effect of relational centrality in either age group. These results suggest that the generative model (Rehder, 2003a) provides a good account of causal categorization in children as well as adults. PMID:22462547

  17. “The Maasai Need Cows and the Cows Need Maasai,” the Use of a Photovoice Approach to Assess Animal Health Needs

    PubMed Central

    van der Meer, Frank; Clancy, Eoin; Thomas, Adam; Kutz, Susan; Hatfield, Jennifer; Orsel, Karin

    2015-01-01

    The Maasai pastoralists in sub-Saharan Africa depend on their livestock for income and food. Livestock production can be significantly improved by addressing animal health concerns. We explored the use of photovoice, a participatory action research method, to strengthen our understanding of the Maasai’s animal health needs. Nine interviewees, representing warriors, elders, and women, identified animal, social, and human health themes. The use of photography provided a new medium for Maasai to express their needs and a focus for researcher–participant communications, thereby facilitating new insights across language and cultural barriers. PMID:26664973

  18. Child Care Subsidy Use and Child Development: Potential Causal Mechanisms

    ERIC Educational Resources Information Center

    Hawkinson, Laura E.

    2011-01-01

    Research using an experimental design is needed to provide firm causal evidence on the impacts of child care subsidy use on child development, and on underlying causal mechanisms since subsidies can affect child development only indirectly via changes they cause in children's early experiences. However, before costly experimental research is…

  19. The Role of Functional Form in Causal-Based Categorization

    ERIC Educational Resources Information Center

    Rehder, Bob

    2015-01-01

    Two experiments tested how the "functional form" of the causal relations that link features of categories affects category-based inferences. Whereas "independent causes" can each bring about an effect by themselves, "conjunctive causes" all need to be present for an effect to occur. The causal model view of category…

  20. Granger Causality and Transfer Entropy Are Equivalent for Gaussian Variables

    NASA Astrophysics Data System (ADS)

    Barnett, Lionel; Barrett, Adam B.; Seth, Anil K.

    2009-12-01

    Granger causality is a statistical notion of causal influence based on prediction via vector autoregression. Developed originally in the field of econometrics, it has since found application in a broader arena, particularly in neuroscience. More recently transfer entropy, an information-theoretic measure of time-directed information transfer between jointly dependent processes, has gained traction in a similarly wide field. While it has been recognized that the two concepts must be related, the exact relationship has until now not been formally described. Here we show that for Gaussian variables, Granger causality and transfer entropy are entirely equivalent, thus bridging autoregressive and information-theoretic approaches to data-driven causal inference.

  1. Causal Cohesion and Story Coherence.

    ERIC Educational Resources Information Center

    Trabasso, Tom; And Others

    Based on the theory that a story's coherence depends directly on the causal cohesiveness of the story's individual events, this paper describes (1) a process by which readers use causal reasoning to connect events, (2) what memory representations result from this reasoning, and (3) the implications of test data on causal reasoning. Following a…

  2. THE CHILD'S CONCEPTION OF PHYSICAL CAUSALITY.

    ERIC Educational Resources Information Center

    PIAGET, JEAN

    THE CHILD'S CONCEPTION OF PHYSICAL CAUSALITY WAS INVESTIGATED. THREE METHODS OF INVESTIGATION WERE USED. THE FIRST METHOD WAS PURELY VERBAL, AND CONSISTED OF A SERIES OF QUESTIONS DIRECTED TO CHILDREN, REGARDING SOME NATURAL PHENOMENON. THE SECOND METHOD INVOLVED A HALF-VERBAL, HALF-PRACTICAL APPROACH, WHEREIN A SPECIFIC REFERENCE TO NATURAL…

  3. From Granger causality to long-term causality: Application to climatic data

    NASA Astrophysics Data System (ADS)

    Smirnov, Dmitry A.; Mokhov, Igor I.

    2009-07-01

    Quantitative characterization of interaction between processes from time series is often required in different fields of natural science including geophysics and biophysics. Typically, one estimates “short-term” influences, e.g., the widely used Granger causality is defined via one-step-ahead predictions. Such an approach does not reveal how strongly the “long-term” behavior of one process under study is affected by the others. To overcome this problem, we introduce the concept of long-term causality, which extends the concept of Granger causality. The long-term causality is estimated from data via empirical modeling and analysis of model dynamics under different conditions. Apart from mathematical examples, we apply both approaches to find out how strongly the global surface temperature (GST) is affected by variations in carbon dioxide atmospheric content, solar activity, and volcanic activity during the last 150 years. Influences of all the three factors on GST are detected with the Granger causality. However, the long-term causality shows that the rise in GST during the last decades can be explained only if the anthropogenic factor (CO2) is taken into account in a model.

  4. The need for comprehensive vulnerability approaches to mirror the multiplicity in mountain hazard risk

    NASA Astrophysics Data System (ADS)

    Keiler, Margreth; Fuchs, Sven

    2014-05-01

    The concept of vulnerability is pillared by multiple disciplinary theories underpinning either a technical or a social origin of the concept and resulting in a range of paradigms for vulnerability quantification. By taking a natural scientific approach we argue that a large number of studies have focused either on damage-loss functions for individual mountain hazards or on semi-quantitative indicator-based approaches for multiple hazards (hazard chains). However, efforts to reduce susceptibility to hazards and to create disaster-resilient communities require intersections among these approaches, as well as among theories originating in natural and social sciences, since human activity cannot be seen independently from the environmental setting. Acknowledging different roots of disciplinary paradigms in risk management, issues determining structural, economic, institutional and social vulnerability have to be more comprehensively addressed in the future with respect to mountain hazards in Europe and beyond. It is argued that structural vulnerability as originator results in considerable economic vulnerability, generated by the institutional settings of dealing with natural hazards and shaped by the overall societal framework. If vulnerability and its counterpart, resilience, is analysed and evaluated by using such a comprehensive approach, a better understanding of the vulnerability-influencing parameters could be achieved, taking into account the interdependencies and interactions between the disciplinary foci. As a result, three key issues should be addressed in future research: (1) Vulnerability requires a new perspective on the relationship between society and environment: not as a duality, but more as a mutually constitutive relationship (including methods for assessment). (2) There is a need for concepts of vulnerability that emphasise the dynamics of temporal and spatial scales, particularly with respect to Global Change processes in mountain regions. (3

  5. Normalizing the causality between time series.

    PubMed

    Liang, X San

    2015-08-01

    Recently, a rigorous yet concise formula was derived to evaluate information flow, and hence the causality in a quantitative sense, between time series. To assess the importance of a resulting causality, it needs to be normalized. The normalization is achieved through distinguishing a Lyapunov exponent-like, one-dimensional phase-space stretching rate and a noise-to-signal ratio from the rate of information flow in the balance of the marginal entropy evolution of the flow recipient. It is verified with autoregressive models and applied to a real financial analysis problem. An unusually strong one-way causality is identified from IBM (International Business Machines Corporation) to GE (General Electric Company) in their early era, revealing to us an old story, which has almost faded into oblivion, about "Seven Dwarfs" competing with a giant for the mainframe computer market. PMID:26382363

  6. Normalizing the causality between time series

    NASA Astrophysics Data System (ADS)

    Liang, X. San

    2015-08-01

    Recently, a rigorous yet concise formula was derived to evaluate information flow, and hence the causality in a quantitative sense, between time series. To assess the importance of a resulting causality, it needs to be normalized. The normalization is achieved through distinguishing a Lyapunov exponent-like, one-dimensional phase-space stretching rate and a noise-to-signal ratio from the rate of information flow in the balance of the marginal entropy evolution of the flow recipient. It is verified with autoregressive models and applied to a real financial analysis problem. An unusually strong one-way causality is identified from IBM (International Business Machines Corporation) to GE (General Electric Company) in their early era, revealing to us an old story, which has almost faded into oblivion, about "Seven Dwarfs" competing with a giant for the mainframe computer market.

  7. Process-outcome interrelationship and standard setting in medical education: the need for a comprehensive approach.

    PubMed

    Christensen, Leif; Karle, Hans; Nystrup, Jørgen

    2007-09-01

    An outcome-based approach to medical education compared to a process/content orientation is currently being discussed intensively. In this article, the process and outcome interrelationship in medical education is discussed, with specific emphasis on the relation to the definition of standards in basic medical education. Perceptions of outcome have always been an integrated element of curricular planning. The present debate underlines the need for stronger focus on learning objectives and outcome assessment in many medical schools around the world. The need to maintain an integrated approach of process/content and outcome is underlined in this paper. A worry is expressed about the taxonomy of learning in pure outcome-based medical education, in which student assessment can be a major determinant for the learning process, leaving the control of the medical curriculum to medical examiners. Moreover, curricula which favour reductionism by stating everything in terms of instrumental outcomes or competences, do face a risk of lowering quality and do become a prey for political interference. Standards based on outcome alone rise unclarified problems in relationship to licensure requirements of medical doctors. It is argued that the alleged dichotomy between process/content and outcome seems artificial, and that formulation of standards in medical education must follow a comprehensive line in curricular planning. PMID:18251034

  8. Interpretation of cardiovascular outcome trials in type 2 diabetes needs a multiaxial approach

    PubMed Central

    Johansen, Odd Erik

    2015-01-01

    In cardiovascular (CV) diabetology a “one-size fits-all” approach needs caution as vasculopathy and CV manifestations in patients with type 2 diabetes (T2D) with short disease duration are different as compared to those with longer duration. This is of relevance when interpreting results of CV outcome trials as responses to any intervention aimed to reduce CV risk might be different in patients with established vasculopathy as compared to those without, where also the duration of the intervention may play a role. Additionally, the mode-of-action of the intervention and its assumed time to peak CV risk modulation need to be taken into account: an intervention with possibly immediate effects, like on blood pressure or other direct functional dynamic parameters such as endothelial function or renal hemodynamics, could likely provide a meaningful impact on CV outcomes over a shorter time span than interventions that primarily target pathways that work on atherosclerotic processes, organ-remodelling, or vessel integrity. We are now faced with CV outcome results to interpret from a plethora of outcomes trials in T2D, some of which are testing the CV risk modulation predominantly beyond glucose lowering, e.g., as is the case for several trials testing the newer therapy classes di-peptidyl peptidase-4 inhibitors, glucagon-like protein-1 receptor analogues and sodium glucose co-transporter-2 inhibitors, and this paper reviews the data that support a call for a multiaxial approach to interpret these results. PMID:26265995

  9. A new approach in climate modelling strategies to provide climate information based on user needs

    NASA Astrophysics Data System (ADS)

    Dell'Aquila, Alessandro; Somot, Samuel; Dubois, Clotilde; Nabat, Pierre; Coppola, Erika

    2014-05-01

    In the framework of CLIMRUN EU FP7 project a new approach to plan the climate modelling activities has been proposed and applied. In particular a bottom-up approach mainly driven by the specific needs of end users has been adopted. In this perspective, the new climate information for Mediterranean region provided from new modelling activity have been tailored on the users needs raised in several Stakeholders Workshops organized at the early stages of the project. At the beginning of the project, several different options of possible developments for new modelling tools have been proposed by climate researchers involved in the project. Taking carefully into account the ranking of priorities suggested by end-users, the climate researchers could set a more focused research line fitting the expectations of stakeholders. New modelling tools to improve the representation and projection of surface wind speed, surface solar radiation, trend of extreme events, temperature of lakes and islands of Mediterranean have been successfully developed. Here we report some of the major outcomes from the new tools and more in general some recommendations about the future role of climate researchers in developing climate services.The results here reported could be useful also in the othe ongoing experiences about climate services such as projects SPECS, EUPORIAS...

  10. Swimming hydrodynamics: ten questions and the technical approaches needed to resolve them

    NASA Astrophysics Data System (ADS)

    Lauder, George V.

    2011-07-01

    Recent experimental and computational studies of swimming hydrodynamics have contributed significantly to our understanding of how animals swim, but much remains to be done. Ten questions are presented here as an avenue to discuss some of the arenas in which progress still is needed and as a means of considering the technical approaches to address these questions. 1. What is the three-dimensional structure of propulsive surfaces? 2. How do propulsive surfaces move in three dimensions? 3. What are the hydrodynamic effects of propulsor deformation during locomotion? 4. How are locomotor kinematics and dynamics altered during unsteady conditions? 5. What is the three-dimensional structure of aquatic animal vortex wakes? 6. To what extent are observed propulsor deformations actively controlled? 7. What is the response of the body and fins of moving animals to external perturbations? 8. How can robotic models help us understand locomotor dynamics of organisms? 9. How do propulsive surfaces interact hydrodynamically during natural motions? 10. What new computational approaches are needed to better understand locomotor hydrodynamics? These ten questions point, not exclusively, toward areas in which progress would greatly enhance our understanding of the hydrodynamics of swimming organisms, and in which the application of new technology will allow continued progress toward understanding the interaction between organisms and the aquatic medium in which they live and move.

  11. Swimming hydrodynamics: ten questions and the technical approaches needed to resolve them

    NASA Astrophysics Data System (ADS)

    Lauder, George V.

    Recent experimental and computational studies of swimming hydrodynamics have contributed significantly to our understanding of how animals swim, but much remains to be done. Ten questions are presented here as an avenue to discuss some of the arenas in which progress still is needed and as a means of considering the technical approaches to address these questions. 1. What is the three-dimensional structure of propulsive surfaces? 2. How do propulsive surfaces move in three dimensions? 3. What are the hydrodynamic effects of propulsor deformation during locomotion? 4. How are locomotor kinematics and dynamics altered during unsteady conditions? 5. What is the three-dimensional structure of aquatic animal vortex wakes? 6. To what extent are observed propulsor deformations actively controlled? 7. What is the response of the body and fins of moving animals to external perturbations? 8. How can robotic models help us understand locomotor dynamics of organisms? 9. How do propulsive surfaces interact hydrodynamically during natural motions? 10. What new computational approaches are needed to better understand locomotor hydrodynamics? These ten questions point, not exclusively, toward areas in which progress would greatly enhance our understanding of the hydrodynamics of swimming organisms, and in which the application of new technology will allow continued progress toward understanding the interaction between organisms and the aquatic medium in which they live and move.

  12. The Newtonian approximation in Causal Dynamical Triangulations

    NASA Astrophysics Data System (ADS)

    Getchell, Adam

    2015-04-01

    I review how to derive Newton's law of universal gravitation from the Weyl strut between two Chazy-Curzon particles. I also briefly review Causal Dynamical Triangulations (CDT), a method for evaluating the path integral from canonical quantum gravity using Regge calculus and restrictions of the class of simplicial manifolds evaluated to those with a defined time foliation, thus enforcing a causal structure. I then discuss how to apply this approach to Causal Dynamical Triangulations, in particular modifying the algorithm to keep two simplicial submanifolds with curvature (i.e. mass) a fixed distance from each other, modulo regularized deviations and across all time slices. I then discuss how to determine if CDT produces an equivalent Weyl strut, which can then be used to obtain the Newtonian limit. I wrap up with a brief discussion of computational methods and code development.

  13. Employee Training Needs and Perceived Value of Training in the Pearl River Delta of China: A Human Capital Development Approach

    ERIC Educational Resources Information Center

    Au, Alan Kai Ming; Altman, Yochanan; Roussel, Josse

    2008-01-01

    Purpose: This paper aims to explore Hong Kong firms' training needs in the Pearl River Delta, a booming region in the fast growing People Republic of China economy, by resorting to a human capital approach. Also, to identify the training policies selected by those firms in order to cater for those needs. Design/methodology/approach: A survey based…

  14. A Hybrid Approach to Finding Relevant Social Media Content for Complex Domain Specific Information Needs

    PubMed Central

    Cameron, Delroy; Sheth, Amit P.; Jaykumar, Nishita; Thirunarayan, Krishnaprasad; Anand, Gaurish; Smith, Gary A.

    2015-01-01

    While contemporary semantic search systems offer to improve classical keyword-based search, they are not always adequate for complex domain specific information needs. The domain of prescription drug abuse, for example, requires knowledge of both ontological concepts and “intelligible constructs” not typically modeled in ontologies. These intelligible constructs convey essential information that include notions of intensity, frequency, interval, dosage and sentiments, which could be important to the holistic needs of the information seeker. In this paper, we present a hybrid approach to domain specific information retrieval that integrates ontology-driven query interpretation with synonym-based query expansion and domain specific rules, to facilitate search in social media on prescription drug abuse. Our framework is based on a context-free grammar (CFG) that defines the query language of constructs interpretable by the search system. The grammar provides two levels of semantic interpretation: 1) a top-level CFG that facilitates retrieval of diverse textual patterns, which belong to broad templates and 2) a low-level CFG that enables interpretation of specific expressions belonging to such textual patterns. These low-level expressions occur as concepts from four different categories of data: 1) ontological concepts, 2) concepts in lexicons (such as emotions and sentiments), 3) concepts in lexicons with only partial ontology representation, called lexico-ontology concepts (such as side effects and routes of administration (ROA)), and 4) domain specific expressions (such as date, time, interval, frequency and dosage) derived solely through rules. Our approach is embodied in a novel Semantic Web platform called PREDOSE, which provides search support for complex domain specific information needs in prescription drug abuse epidemiology. When applied to a corpus of over 1 million drug abuse-related web forum posts, our search framework proved effective in retrieving

  15. Meeting the Needs for Released Nanomaterials Required for Further Testing-The SUN Approach.

    PubMed

    Nowack, Bernd; Boldrin, Alessio; Caballero, Alejandro; Hansen, Steffen Foss; Gottschalk, Fadri; Heggelund, Laura; Hennig, Michael; Mackevica, Aiga; Maes, Hanna; Navratilova, Jana; Neubauer, Nicole; Peters, Ruud; Rose, Jerome; Schäffer, Andreas; Scifo, Lorette; van Leeuwen, Stefan van; von der Kammer, Frank; Wohlleben, Wendel; Wyrwoll, Anne; Hristozov, Danail

    2016-03-15

    The analysis of the potential risks of engineered nanomaterials (ENM) has so far been almost exclusively focused on the pristine, as-produced particles. However, when considering a life-cycle perspective, it is clear that ENM released from genuine products during manufacturing, use, and disposal is far more relevant. Research on the release of materials from nanoproducts is growing and the next necessary step is to investigate the behavior and effects of these released materials in the environment and on humans. Therefore, sufficient amounts of released materials need to be available for further testing. In addition, ENM-free reference materials are needed since many processes not only release ENM but also nanosized fragments from the ENM-containing matrix that may interfere with further tests. The SUN consortium (Project on "Sustainable Nanotechnologies", EU seventh Framework funding) uses methods to characterize and quantify nanomaterials released from composite samples that are exposed to environmental stressors. Here we describe an approach to provide materials in hundreds of gram quantities mimicking actual released materials from coatings and polymer nanocomposites by producing what is called "fragmented products" (FP). These FP can further be exposed to environmental conditions (e.g., humidity, light) to produce "weathered fragmented products" (WFP) or can be subjected to a further size fractionation to isolate "sieved fragmented products" (SFP) that are representative for inhalation studies. In this perspective we describe the approach, and the used methods to obtain released materials in amounts large enough to be suitable for further fate and (eco)toxicity testing. We present a case study (nanoparticulate organic pigment in polypropylene) to show exemplarily the procedures used to produce the FP. We present some characterization data of the FP and discuss critically the further potential and the usefulness of the approach we developed. PMID:26866387

  16. Approaches for exposure characterization and data needs for hazardous waste site assessment.

    PubMed Central

    Waldman, J M

    1995-01-01

    This article provides an understanding of the approaches for determining exposure and dose to populations in the vicinity of hazardous waste sites. A review of the federal legislation and jurisdiction for assessments is provided, and the approaches of the U.S. Environmental Protection Agency and the Agency for Toxic Substances and Disease Registry are compared. These methods strive to aid in the evaluation of public health impacts of contaminants that were, are, or may be released to the community, and they are concerned with various aspects of the contaminant fate, human contact, and toxic response for chemicals of concern. Such approaches have been designed for generic contamination scenarios, but they aim to be applicable to a wide range of chemicals and sites in the real world. Along with any modeling framework for exposure and dose characterization, detailed information or real data are requisite for the completion of any site-specific assessment. What kinds of data are needed and where they may be found are also discussed. A comprehensive framework for exposure characterization, recently proposed by Georgopoulos and Lioy, is outlined. The framework is one employing the following elements: chemodynamic analyses of sources and receptors; characterization of the target population; toxicokinetic/toxicodynamic analyses; uncertainty/error analyses; and evaluation of the characterization performance. PMID:7621812

  17. Causality in physiological signals.

    PubMed

    Müller, Andreas; Kraemer, Jan F; Penzel, Thomas; Bonnemeier, Hendrik; Kurths, Jürgen; Wessel, Niels

    2016-05-01

    Health is one of the most important non-material assets and thus also has an enormous influence on material values, since treating and preventing diseases is expensive. The number one cause of death worldwide today originates in cardiovascular diseases. For these reasons the aim of understanding the functions and the interactions of the cardiovascular system is and has been a major research topic throughout various disciplines for more than a hundred years. The purpose of most of today's research is to get as much information as possible with the lowest possible effort and the least discomfort for the subject or patient, e.g. via non-invasive measurements. A family of tools whose importance has been growing during the last years is known under the headline of coupling measures. The rationale for this kind of analysis is to identify the structure of interactions in a system of multiple components. Important information lies for example in the coupling direction, the coupling strength, and occurring time lags. In this work, we will, after a brief general introduction covering the development of cardiovascular time series analysis, introduce, explain and review some of the most important coupling measures and classify them according to their origin and capabilities in the light of physiological analyses. We will begin with classical correlation measures, go via Granger-causality-based tools, entropy-based techniques (e.g. momentary information transfer), nonlinear prediction measures (e.g. mutual prediction) to symbolic dynamics (e.g. symbolic coupling traces). All these methods have contributed important insights into physiological interactions like cardiorespiratory coupling, neuro-cardio-coupling and many more. Furthermore, we will cover tools to detect and analyze synchronization and coordination (e.g. synchrogram and coordigram). As a last point we will address time dependent couplings as identified using a recent approach employing ensembles of time series. The

  18. To Infinity and Beyond: Using a Narrative Approach to Identify Training Needs for Unknown and Dynamic Situations

    ERIC Educational Resources Information Center

    Dachner, Alison M.; Saxton, Brian M.; Noe, Raymond A.; Keeton, Kathryn E.

    2013-01-01

    Training effectiveness depends on conducting a thorough needs assessment. Traditional needs assessment methods are insufficient for today's business environment characterized by rapid pace, risk, and uncertainty. To overcome the deficiencies of traditional needs assessment methods, a narrative-based unstructured interview approach with…

  19. Supporting Early Childhood Preservice Teachers in Their Work with Children and Families with Complex Needs: A Strengths Approach

    ERIC Educational Resources Information Center

    Fenton, Angela; McFarland-Piazza, Laura

    2014-01-01

    This article explores the potential of tailoring the inherent principles of the Strengths Approach (McCashen, 2005) for preparing early childhood educators to work with children and families with complex needs. The term "Strengths Approach" (capitalized) is presented in the article as the name of a specific approach developed by St.…

  20. Quantum information causality.

    PubMed

    Pitalúa-García, Damián

    2013-05-24

    How much information can a transmitted physical system fundamentally communicate? We introduce the principle of quantum information causality, which states the maximum amount of quantum information that a quantum system can communicate as a function of its dimension, independently of any previously shared quantum physical resources. We present a new quantum information task, whose success probability is upper bounded by the new principle, and show that an optimal strategy to perform it combines the quantum teleportation and superdense coding protocols with a task that has classical inputs. PMID:23745844

  1. Causal Entropic Forces

    NASA Astrophysics Data System (ADS)

    Wissner-Gross, A. D.; Freer, C. E.

    2013-04-01

    Recent advances in fields ranging from cosmology to computer science have hinted at a possible deep connection between intelligence and entropy maximization, but no formal physical relationship between them has yet been established. Here, we explicitly propose a first step toward such a relationship in the form of a causal generalization of entropic forces that we find can cause two defining behaviors of the human “cognitive niche”—tool use and social cooperation—to spontaneously emerge in simple physical systems. Our results suggest a potentially general thermodynamic model of adaptive behavior as a nonequilibrium process in open systems.

  2. Fine Needle Aspiration Cytology vs. the Postoperative Histology - the Continuing Need for Multi-Disciplinary Approach?

    PubMed

    Gill, G; Kalyanasundaram, K; Varughese, G; Wilson, P; Varadhan, L

    2016-07-01

    We set out to investigate the concordance rates that were observed between fine needle aspiration cytology (FNA) compared with that of the post operative histology obtained for thyroid nodules over an 8 year period at a large university hospital.A retrospective analysis of 355 cases was conducted; patients operated for hyperthyroidism were excluded for the purposes of this study. We identified malignancy in a total of 101 cases (28%) The chance of malignancy with 2 Thy1 specimens was 5% in this study and 9% was observed in those with a Thy 2 FNA. On the converse, 7% of patient had malignant cytology on FNA though post-operative histology turned out to be benign.This therefore highlights the potential for discordance between thyroid FNA cytology and post-operative histology in the assessment of any thyroid nodule and thus reinforcing the need for a multidisciplinary approach in the assessment of all thyroid nodules. PMID:27223871

  3. Sleepwalking Into Infertility: The Need for a Public Health Approach Toward Advanced Maternal Age.

    PubMed

    Lemoine, Marie-Eve; Ravitsky, Vardit

    2015-01-01

    In Western countries today, a growing number of women delay motherhood until their late 30s and even 40s, as they invest time in pursuing education and career goals before starting a family. This social trend results from greater gender equality and expanded opportunities for women and is influenced by the availability of contraception and assisted reproductive technologies (ART). However, advanced maternal age is associated with increased health risks, including infertility. While individual medical solutions such as ART and elective egg freezing can promote reproductive autonomy, they entail significant risks and limitations. We thus argue that women should be better informed regarding the risks of advanced maternal age and ART, and that these individual solutions need to be supplemented by a public health approach, including policy measures that provide women with the opportunity to start a family earlier in life without sacrificing personal career goals. PMID:26575814

  4. The lesson of causal discovery algorithms for quantum correlations: causal explanations of Bell-inequality violations require fine-tuning

    NASA Astrophysics Data System (ADS)

    Wood, Christopher J.; Spekkens, Robert W.

    2015-03-01

    An active area of research in the fields of machine learning and statistics is the development of causal discovery algorithms, the purpose of which is to infer the causal relations that hold among a set of variables from the correlations that these exhibit . We apply some of these algorithms to the correlations that arise for entangled quantum systems. We show that they cannot distinguish correlations that satisfy Bell inequalities from correlations that violate Bell inequalities, and consequently that they cannot do justice to the challenges of explaining certain quantum correlations causally. Nonetheless, by adapting the conceptual tools of causal inference, we can show that any attempt to provide a causal explanation of nonsignalling correlations that violate a Bell inequality must contradict a core principle of these algorithms, namely, that an observed statistical independence between variables should not be explained by fine-tuning of the causal parameters. In particular, we demonstrate the need for such fine-tuning for most of the causal mechanisms that have been proposed to underlie Bell correlations, including superluminal causal influences, superdeterminism (that is, a denial of freedom of choice of settings), and retrocausal influences which do not introduce causal cycles.

  5. Educational Needs Assessment for Psychiatry Residents to Prevent Suicide: A Qualitative Approach

    PubMed Central

    Barekatain, Majid; Aminoroaia, Mahin; Samimi, Seyed Mehdi Ardestani; Rajabi, Fatemeh; Attari, Abbas

    2013-01-01

    Background: Suicide is a commonly encountered and stressful event in professional life of any psychiatrist. Suicide risk assessment is a major gateway to patient treatment and management. It is a core competency requirement in training of psychiatry. The present study designed to assesseducational needsfor suicide prevention in residents of psychiatry in two medical schools in Iran, Isfahan University of Medical Sciences (IUMS) and Shahid Beheshti Medical University (SBUMS) inTehran. Methods: This was a qualitative triangulation study, conducted in two steps. The first step was based on a phenomenological approach and the second was based on focus groups. The studied population was the psychiatric residents of IUMS and SBUMS. Purposive sampling was implemented until saturation. Interviews were performed. Colaizzi method was used to analyze the data. In the second step, participants attended a session, in which all final codes of the first step were discussed, and regarding the views, educational priorities and needs were listed. Results: A total of 2047 codes, extracted from 31 interviews, analyzed through Colaizzi method, were categorized in three groups: Educational, facilities and processes, human resources. Conclusions: According to defects of current educational program, we suggest regular reevaluations and revisions of clinical training programs according to current needs. PMID:24319561

  6. Development of new treatment approaches for epilepsy: unmet needs and opportunities.

    PubMed

    French, Jacqueline A; White, H Steve; Klitgaard, Henrik; Holmes, Gregory L; Privitera, Michael D; Cole, Andrew J; Quay, Ellinor; Wiebe, Samuel; Schmidt, Dieter; Porter, Roger J; Arzimanoglou, Alexis; Trinka, Eugen; Perucca, Emilio

    2013-08-01

    A working group was created to address clinical "gaps to care" as well as opportunities for development of new treatment approaches for epilepsy. The working group primarily comprised clinicians, trialists, and pharmacologists. The group identified a need for better animal models for both efficacy and tolerability, and noted that animal models for potential disease-modifying or antiepileptogenic effect should mirror conditions in human trials. For antiseizure drugs (ASDs), current animal models have not been validated with respect to their relationship to efficacy in common epilepsy syndromes. The group performed an "expert opinion" survey of perceived efficacy of the available ASDs, and identified a specific unmet need for ASDs to treat tonic-atonic and myoclonic seizures. No correlation has as yet been demonstrated between animal models of tolerability and adverse effects (AEs), versus tolerability in humans. There is a clear opportunity for improved therapies in relation to dose-related AEs. The group identified common and rare epilepsy syndromes that could represent opportunities for clinical trials. They identified opportunities for antiepileptogenic (AEG) therapies in both adults and children, acknowledging that the presence of a biomarker would substantially improve the chances of a successful trial. However, the group acknowledged that disease-modifying therapies (given after the first seizure or after the development of epilepsy) would be easier to study than AEG therapies. PMID:23909849

  7. Conceptualizing and applying a minimum basic needs approach in southern Philippines.

    PubMed

    Heinonen, T; Mercader, M; Quianzon, J L; Peñera-Torralba, M; Baluis, L

    2000-06-01

    This study, a collaboration between Canadian and Filipino researchers, focuses on how the national government's Minimum Basic Needs (MBN) Approach has been implemented at the local level in some selected sites in Region XI on the Philippine island of Mindanao. This case study of MBN implementation focuses on the experiences of three municipalities and three barangays (villages) within them. The research explores, through interviews and group discussions, what the mayors, technical working groups and volunteer health workers in these areas thought about MBN and how they participated in the initiative. The objectives of the study were: to explore models of MBN data utilization at the municipal and barangay levels; to understand how the MBN data guided decision-making about community priorities and resource allocation; to examine the role that community volunteers played in promoting the use of MBN data, and in community health and development activities which ensued; and to determine what factors challenged or encouraged the use of MBN data for social development at the barangay level. In all the sites, MBN had some impact, most often due to methods of concentrating information on unmet basic needs locally and making use of it in planning and project development processes. The findings show that although there is still some way to go before MBN is effectively integrated into local planning and project development, some responses to problems have been implemented and innovative projects were undertaken or being considered. PMID:10837043

  8. From computer-assisted intervention research to clinical impact: The need for a holistic approach.

    PubMed

    Ourselin, Sébastien; Emberton, Mark; Vercauteren, Tom

    2016-10-01

    The early days of the field of medical image computing (MIC) and computer-assisted intervention (CAI), when publishing a strong self-contained methodological algorithm was enough to produce impact, are over. As a community, we now have substantial responsibility to translate our scientific progresses into improved patient care. In the field of computer-assisted interventions, the emphasis is also shifting from the mere use of well-known established imaging modalities and position trackers to the design and combination of innovative sensing, elaborate computational models and fine-grained clinical workflow analysis to create devices with unprecedented capabilities. The barriers to translating such devices in the complex and understandably heavily regulated surgical and interventional environment can seem daunting. Whether we leave the translation task mostly to our industrial partners or welcome, as researchers, an important share of it is up to us. We argue that embracing the complexity of surgical and interventional sciences is mandatory to the evolution of the field. Being able to do so requires large-scale infrastructure and a critical mass of expertise that very few research centres have. In this paper, we emphasise the need for a holistic approach to computer-assisted interventions where clinical, scientific, engineering and regulatory expertise are combined as a means of moving towards clinical impact. To ensure that the breadth of infrastructure and expertise required for translational computer-assisted intervention research does not lead to a situation where the field advances only thanks to a handful of exceptionally large research centres, we also advocate that solutions need to be designed to lower the barriers to entry. Inspired by fields such as particle physics and astronomy, we claim that centralised very large innovation centres with state of the art technology and health technology assessment capabilities backed by core support staff and open

  9. Innovative laser based approaches to laryngeal cancer: what an engineer and physicist need to know

    NASA Astrophysics Data System (ADS)

    Burns, James A.

    2008-02-01

    Innovative laser-based approaches to laryngeal cancer include the clinical applications of two new technologies, photoangiolysis using a 532nm wavelength pulsed-KTP laser and fiber-based cutting using a 2μm wavelength thulium laser. Photoangiolysis is well-suited for treatment of minimally invasive glottic cancer and allows maximum preservation of phonatory surfaces needed for optimal voicing. The thulium laser offers an alternative to the carbon dioxide laser as an endolaryngeal cutting tool due to its enhanced hemostatic properties and fiber-based delivery. Clinical examples of pulsed-KTP laser involution of early glottic cancer will be presented in order to highlight the concept of targeting tumor angiogenesis in treating laryngeal cancer. The surgical experience using the thulium laser for complex endoscopic endolaryngeal excisions of large laryngeal cancers is presented to demonstrate the expanded clinical applications of endolaryngeal cutting offered by this laser. The laryngeal tissue effects of various laser power and pulse width (PW) settings, mode of delivery, active cooling to reduce thermal trauma, and wavelength selection have been extensively studied for the KTP and thulium lasers in both ex-vivo and live-perfusing models. The results from these studies, included herein, determine the clinical efficacy and safety of these innovative laser-based approaches to laryngeal cancer.

  10. Modelling approaches for coastal simulation based on cellular automata: the need and potential.

    PubMed

    Dearing, J A; Richmond, N; Plater, A J; Wolf, J; Prandle, D; Coulthard, T J

    2006-04-15

    The paper summarizes the theoretical and practical needs for cellular automata (CA)-type models in coastal simulation, and describes early steps in the development of a CA-based model for estuarine sedimentation. It describes the key approaches and formulae used for tidal, wave and sediment processes in a prototype integrated cellular model for coastal simulation designed to simulate estuary sedimentary responses during the tidal cycle in the short-term and climate driven changes in sea-level in the long-term. Results of simple model testing for both one-dimensional and two-dimensional models, and a preliminary parameterization for the Blackwater Estuary, UK, are shown. These reveal a good degree of success in using a CA-type model for water and sediment transport as a function of water level and wave height, but tidal current vectors are not effectively simulated in the approach used. The research confirms that a CA-type model for the estuarine sediment system is feasible, with a real prospect for coupling to existing catchment and nearshore beach/cliff models to produce integrated coastal simulators of sediment response to climate, sea-level change and human actions. PMID:16537155

  11. Atomic and Molecular Data Needs for Radiation Damage Modeling: Multiscale Approach

    NASA Astrophysics Data System (ADS)

    Yakubovich, Alexander V.; Surdutovich, Eugene; Solov'yov, Andrey V.

    2011-05-01

    We present a brief overview of the multiscale approach towards understanding of the processes responsible for the radiation damage caused by energetic ions. This knowledge is very important, because it can be utilized in the ion-beam cancer therapy, which is one of the most advanced modern techniques to cure certain type of cancer. The central element of the multiscale approach is the theoretical evaluation and quantification of the DNA damage within cell environment. To achieve this goal one needs a significant amount of data on various atomic and molecular processes involved into the cascade of events starting with the ion entering and propagation in the biological medium and resulting in the DNA damage. The discussion of the follow up biological processes are beyond the scope of this brief overview. We consider different paths of the DNA damage and focus on the the illustration of the thermo-mechanical effects caused by the propagation of ions through the biological environment and in particular on the possibility of the creation of the shock waves in the vicinity of the ion tracks. We demonstrate that at the initial stages after ion's passage the shock wave is so strong that it can contribute to the DNA damage due to large pressure gradients developed at the distances of a few nanometers from the ionic tracks. This novel mechanism of the DNA damage provides an important contribution to the cumulative biodamage caused by low-energy secondary electrons, holes and free radicals.

  12. Atomic and Molecular Data Needs for Radiation Damage Modeling: Multiscale Approach

    SciTech Connect

    Yakubovich, Alexander V.; Solov'yov, Andrey V.; Surdutovich, Eugene

    2011-05-11

    We present a brief overview of the multiscale approach towards understanding of the processes responsible for the radiation damage caused by energetic ions. This knowledge is very important, because it can be utilized in the ion-beam cancer therapy, which is one of the most advanced modern techniques to cure certain type of cancer. The central element of the multiscale approach is the theoretical evaluation and quantification of the DNA damage within cell environment. To achieve this goal one needs a significant amount of data on various atomic and molecular processes involved into the cascade of events starting with the ion entering and propagation in the biological medium and resulting in the DNA damage. The discussion of the follow up biological processes are beyond the scope of this brief overview. We consider different paths of the DNA damage and focus on the the illustration of the thermo-mechanical effects caused by the propagation of ions through the biological environment and in particular on the possibility of the creation of the shock waves in the vicinity of the ion tracks. We demonstrate that at the initial stages after ion's passage the shock wave is so strong that it can contribute to the DNA damage due to large pressure gradients developed at the distances of a few nanometers from the ionic tracks. This novel mechanism of the DNA damage provides an important contribution to the cumulative biodamage caused by low-energy secondary electrons, holes and free radicals.

  13. Treatment compliance and effectiveness of a cognitive behavioural intervention for low back pain: a complier average causal effect approach to the BeST data set

    PubMed Central

    2014-01-01

    Background Group cognitive behavioural intervention (CBI) is effective in reducing low-back pain and disability in comparison to advice in primary care. The aim of this analysis was to investigate the impact of compliance on estimates of treatment effect and to identify factors associated with compliance. Methods In this multicentre trial, 701 adults with troublesome sub-acute or chronic low-back pain were recruited from 56 general practices. Participants were randomised to advice (control n = 233) or advice plus CBI (n = 468). Compliance was specified a priori as attending a minimum of three group sessions and the individual assessment. We estimated the complier average causal effect (CACE) of treatment. Results Comparison of the CACE estimate of the mean treatment difference to the intention-to-treat (ITT) estimate at 12 months showed a greater benefit of CBI amongst participants compliant with treatment on the Roland Morris Questionnaire (CACE: 1.6 points, 95% CI 0.51 to 2.74; ITT: 1.3 points, 95% CI 0.55 to 2.07), the Modified Von Korff disability score (CACE: 12.1 points, 95% CI 6.07 to 18.17; ITT: 8.6 points, 95% CI 4.58 to 12.64) and the Modified von Korff pain score (CACE: 10.4 points, 95% CI 4.64 to 16.10; ITT: 7.0 points, 95% CI 3.26 to 10.74). People who were non-compliant were younger and had higher pain scores at randomisation. Conclusions Treatment compliance is important in the effectiveness of group CBI. Younger people and those with more pain are at greater risk of non-compliance. Trial registration Current Controlled Trials ISRCTN54717854 PMID:24423146

  14. Reconstructing Causal Biological Networks through Active Learning.

    PubMed

    Cho, Hyunghoon; Berger, Bonnie; Peng, Jian

    2016-01-01

    Reverse-engineering of biological networks is a central problem in systems biology. The use of intervention data, such as gene knockouts or knockdowns, is typically used for teasing apart causal relationships among genes. Under time or resource constraints, one needs to carefully choose which intervention experiments to carry out. Previous approaches for selecting most informative interventions have largely been focused on discrete Bayesian networks. However, continuous Bayesian networks are of great practical interest, especially in the study of complex biological systems and their quantitative properties. In this work, we present an efficient, information-theoretic active learning algorithm for Gaussian Bayesian networks (GBNs), which serve as important models for gene regulatory networks. In addition to providing linear-algebraic insights unique to GBNs, leading to significant runtime improvements, we demonstrate the effectiveness of our method on data simulated with GBNs and the DREAM4 network inference challenge data sets. Our method generally leads to faster recovery of underlying network structure and faster convergence to final distribution of confidence scores over candidate graph structures using the full data, in comparison to random selection of intervention experiments. PMID:26930205

  15. Reconstructing Causal Biological Networks through Active Learning

    PubMed Central

    Cho, Hyunghoon; Berger, Bonnie; Peng, Jian

    2016-01-01

    Reverse-engineering of biological networks is a central problem in systems biology. The use of intervention data, such as gene knockouts or knockdowns, is typically used for teasing apart causal relationships among genes. Under time or resource constraints, one needs to carefully choose which intervention experiments to carry out. Previous approaches for selecting most informative interventions have largely been focused on discrete Bayesian networks. However, continuous Bayesian networks are of great practical interest, especially in the study of complex biological systems and their quantitative properties. In this work, we present an efficient, information-theoretic active learning algorithm for Gaussian Bayesian networks (GBNs), which serve as important models for gene regulatory networks. In addition to providing linear-algebraic insights unique to GBNs, leading to significant runtime improvements, we demonstrate the effectiveness of our method on data simulated with GBNs and the DREAM4 network inference challenge data sets. Our method generally leads to faster recovery of underlying network structure and faster convergence to final distribution of confidence scores over candidate graph structures using the full data, in comparison to random selection of intervention experiments. PMID:26930205

  16. Demystifying Concepts of Epidemic and Causal Association for Public Health Students--A Pedagogical Approach to Promote Critical and Analytical Thinking

    ERIC Educational Resources Information Center

    Patil, Rajan R.

    2011-01-01

    Epidemiology is a difficult but an important subject in public health curriculum. As teachers, we need to be very innovative in teaching the core concepts in epidemiology since it is basically a research oriented subject that calls for enormous application of logic and mathematical skills. Very often, complex epidemiological concepts need to be…

  17. Experimental test of nonlocal causality.

    PubMed

    Ringbauer, Martin; Giarmatzi, Christina; Chaves, Rafael; Costa, Fabio; White, Andrew G; Fedrizzi, Alessandro

    2016-08-01

    Explaining observations in terms of causes and effects is central to empirical science. However, correlations between entangled quantum particles seem to defy such an explanation. This implies that some of the fundamental assumptions of causal explanations have to give way. We consider a relaxation of one of these assumptions, Bell's local causality, by allowing outcome dependence: a direct causal influence between the outcomes of measurements of remote parties. We use interventional data from a photonic experiment to bound the strength of this causal influence in a two-party Bell scenario, and observational data from a Bell-type inequality test for the considered models. Our results demonstrate the incompatibility of quantum mechanics with a broad class of nonlocal causal models, which includes Bell-local models as a special case. Recovering a classical causal picture of quantum correlations thus requires an even more radical modification of our classical notion of cause and effect. PMID:27532045

  18. Experimental test of nonlocal causality

    PubMed Central

    Ringbauer, Martin; Giarmatzi, Christina; Chaves, Rafael; Costa, Fabio; White, Andrew G.; Fedrizzi, Alessandro

    2016-01-01

    Explaining observations in terms of causes and effects is central to empirical science. However, correlations between entangled quantum particles seem to defy such an explanation. This implies that some of the fundamental assumptions of causal explanations have to give way. We consider a relaxation of one of these assumptions, Bell’s local causality, by allowing outcome dependence: a direct causal influence between the outcomes of measurements of remote parties. We use interventional data from a photonic experiment to bound the strength of this causal influence in a two-party Bell scenario, and observational data from a Bell-type inequality test for the considered models. Our results demonstrate the incompatibility of quantum mechanics with a broad class of nonlocal causal models, which includes Bell-local models as a special case. Recovering a classical causal picture of quantum correlations thus requires an even more radical modification of our classical notion of cause and effect. PMID:27532045

  19. MINIMIZING COGNITIVE ERRORS IN SITE-SPECIFIC CAUSAL ASSESSMENT

    EPA Science Inventory

    Interest in causal investigations in aquatic systems has been a natural outgrowth of the increased use of biological monitoring to characterize the condition of resources. Although biological monitoring approaches are critical tools for detecting whether effects are occurring, t...

  20. Causal-explanatory pluralism: How intentions, functions, and mechanisms influence causal ascriptions.

    PubMed

    Lombrozo, Tania

    2010-12-01

    Both philosophers and psychologists have argued for the existence of distinct kinds of explanations, including teleological explanations that cite functions or goals, and mechanistic explanations that cite causal mechanisms. Theories of causation, in contrast, have generally been unitary, with dominant theories focusing either on counterfactual dependence or on physical connections. This paper argues that both approaches to causation are psychologically real, with different modes of explanation promoting judgments more or less consistent with each approach. Two sets of experiments isolate the contributions of counterfactual dependence and physical connections in causal ascriptions involving events with people, artifacts, or biological traits, and manipulate whether the events are construed teleologically or mechanistically. The findings suggest that when events are construed teleologically, causal ascriptions are sensitive to counterfactual dependence and relatively insensitive to the presence of physical connections, but when events are construed mechanistically, causal ascriptions are sensitive to both counterfactual dependence and physical connections. The conclusion introduces an account of causation, an "exportable dependence theory," that provides a way to understand the contributions of physical connections and teleology in terms of the functions of causal ascriptions. PMID:20801434

  1. Identifying children in need of ancillary and enabling services: a population approach.

    PubMed

    Benedict, Ruth E; Farel, Anita M

    2003-12-01

    Children with chronic or disabling conditions use health, education and social services at a higher rate than their healthy peers. Estimates of the number of children in need of these specialized services are widely varied and often depend on categorical definitions that do not account for either the diversity or commonality of their experiences. Developing methods for identifying the population in need of services, particularly children likely to use long-term ancillary (audiology, occupational, physical or speech therapy, or social work) and/or enabling services (special equipment, personal care assistance, respite care, transportation, or environmental modifications), is essential for effective policy and program implementation. This study examines several recent attempts to operationalize definitions of children with chronic conditions using a noncategorical classification approach. Particular emphasis is placed on the subgroup of children identified as having functional limitations. Proposed operational definitions of children with functional limitations are compared using data from the 1994-1995 Disability Supplement to the US National Health Interview Survey. Estimates of the number of children reported to be using ancillary and enabling services are generated and compared across operational definitions of functional limitation as well as by the number, severity, and type (i.e. mobility, self-care, communication/sensory, social cognition/learning ability) of limitation. Depending on the operational definition selected, 9-14% of US community-dwelling children are estimated to have functional limitations. Among children with limitations, 26-30% regularly use ancillary services and 11-14% use enabling services. The strengths, limitations, and potential applications for each operational definition are discussed. PMID:14512235

  2. The urgent need to change the current medical approach on tobacco cessation in Latin America.

    PubMed

    Ponciano-Rodríguez, Guadalupe

    2010-01-01

    Despite of the accumulation of scientific evidence confirming the health consequences of smoking and the new paradigm of smoking as a disease where nicotine is the drug that modifies the functional and morphological characteristics of the brain in dependent smokers, tobacco smoking continues as an important public health problem in many Latin American countries. In contrast with big advances in the tobacco control area, as an example the Framework Convention on Tobacco Control signed by 168 countries, the role of health professional in the fight against tobacco is still less than ideal. In many Latin American schools of medicine, deficiencies in medical education has led to insecure physicians when they have to motivate their patients to stop smoking or to prevent young people to begin tobacco consumption. If each general practitioner or specialist during their daily medical assistance could talk to their smoker patients about the big benefits of stop smoking and support them to get free of tobacco, we would be winning a battle against smoking. Also if we could achieve generations of young non smoking doctors, who could be a real example for patients, this could also impact the prevalence of smokers. In this article we analyze the neurobiological bases of nicotine addiction, which we think are missing in the medical curriculum and could help doctors to understand tobacco smoking as a disease rather than a risk factor, and discuss the main reasons supporting an urgent change in the medical approach of tobacco cessation in Latin America as well as the need to actualize the medical curriculum in order to give physicians the skills needed to intervene successfully with their smoker patients and to be themselves non smokers. PMID:21243210

  3. Structural Equations and Causal Explanations: Some Challenges for Causal SEM

    ERIC Educational Resources Information Center

    Markus, Keith A.

    2010-01-01

    One common application of structural equation modeling (SEM) involves expressing and empirically investigating causal explanations. Nonetheless, several aspects of causal explanation that have an impact on behavioral science methodology remain poorly understood. It remains unclear whether applications of SEM should attempt to provide complete…

  4. Need to use probabilistic risk approach in performance assessment of waste disposal facilities

    SciTech Connect

    Bonano, E.J.; Gallegos, D.P.

    1991-01-01

    Regulations governing the disposal of radioactive, hazardous, and/or mixed wastes will likely require, either directly or indirectly, that the performance of disposal facilities be assessed quantitatively. Such analyses, commonly called performance assessments,'' rely on the use of predictive models to arrive at a quantitative estimate of the potential impact of disposal on the environment and the safety and health of the public. It has been recognized that a suite of uncertainties affect the results of a performance assessment. These uncertainties are conventionally categorized as (1) uncertainty in the future state of the disposal system (facility and surrounding medium), (2) uncertainty in models (including conceptual models, mathematical models, and computer codes), and (3) uncertainty in data and parameters. Decisions regarding the suitability of a waste disposal facility must be made in light of these uncertainties. Hence, an approach is needed that would allow the explicit consideration of these uncertainties so that their impact on the estimated consequences of disposal can be evaluated. While most regulations for waste disposal do not prescribe the consideration of uncertainties, it is proposed that, even in such cases, a meaningful decision regarding the suitability of a waste disposal facility cannot be made without considering the impact of the attendant uncertainties. A probabilistic risk assessment (PRA) approach provides the formalism for considering the uncertainties and the technical basis that the decision makers can use in discharging their duties. A PRA methodology developed and demonstrated for the disposal of high-level radioactive waste provides a general framework for assessing the disposal of all types of wastes (radioactive, hazardous, and mixed). 15 refs., 1 fig., 1 tab.

  5. Causal electromagnetic interaction equations

    SciTech Connect

    Zinoviev, Yury M.

    2011-02-15

    For the electromagnetic interaction of two particles the relativistic causal quantum mechanics equations are proposed. These equations are solved for the case when the second particle moves freely. The initial wave functions are supposed to be smooth and rapidly decreasing at the infinity. This condition is important for the convergence of the integrals similar to the integrals of quantum electrodynamics. We also consider the singular initial wave functions in the particular case when the second particle mass is equal to zero. The discrete energy spectrum of the first particle wave function is defined by the initial wave function of the free-moving second particle. Choosing the initial wave functions of the free-moving second particle it is possible to obtain a practically arbitrary discrete energy spectrum.

  6. Causality & holographic entanglement entropy

    NASA Astrophysics Data System (ADS)

    Headrick, Matthew; Hubeny, Veronika E.; Lawrence, Albion; Rangamani, Mukund

    2014-12-01

    We identify conditions for the entanglement entropy as a function of spatial region to be compatible with causality in an arbitrary relativistic quantum field theory. We then prove that the covariant holographic entanglement entropy prescription (which relates entanglement entropy of a given spatial region on the boundary to the area of a certain extremal surface in the bulk) obeys these conditions, as long as the bulk obeys the null energy condition. While necessary for the validity of the prescription, this consistency requirement is quite nontrivial from the bulk standpoint, and therefore provides important additional evidence for the prescription. In the process, we introduce a codimension-zero bulk region, named the entanglement wedge, naturally associated with the given boundary spatial region. We propose that the entanglement wedge is the most natural bulk region corresponding to the boundary reduced density matrix.

  7. Spatio-temporal Granger causality: a new framework

    PubMed Central

    Luo, Qiang; Lu, Wenlian; Cheng, Wei; Valdes-Sosa, Pedro A.; Wen, Xiaotong; Ding, Mingzhou; Feng, Jianfeng

    2015-01-01

    That physiological oscillations of various frequencies are present in fMRI signals is the rule, not the exception. Herein, we propose a novel theoretical framework, spatio-temporal Granger causality, which allows us to more reliably and precisely estimate the Granger causality from experimental datasets possessing time-varying properties caused by physiological oscillations. Within this framework, Granger causality is redefined as a global index measuring the directed information flow between two time series with time-varying properties. Both theoretical analyses and numerical examples demonstrate that Granger causality is a monotonically increasing function of the temporal resolution used in the estimation. This is consistent with the general principle of coarse graining, which causes information loss by smoothing out very fine-scale details in time and space. Our results confirm that the Granger causality at the finer spatio-temporal scales considerably outperforms the traditional approach in terms of an improved consistency between two resting-state scans of the same subject. To optimally estimate the Granger causality, the proposed theoretical framework is implemented through a combination of several approaches, such as dividing the optimal time window and estimating the parameters at the fine temporal and spatial scales. Taken together, our approach provides a novel and robust framework for estimating the Granger causality from fMRI, EEG, and other related data. PMID:23643924

  8. Spatio-temporal Granger causality: a new framework.

    PubMed

    Luo, Qiang; Lu, Wenlian; Cheng, Wei; Valdes-Sosa, Pedro A; Wen, Xiaotong; Ding, Mingzhou; Feng, Jianfeng

    2013-10-01

    That physiological oscillations of various frequencies are present in fMRI signals is the rule, not the exception. Herein, we propose a novel theoretical framework, spatio-temporal Granger causality, which allows us to more reliably and precisely estimate the Granger causality from experimental datasets possessing time-varying properties caused by physiological oscillations. Within this framework, Granger causality is redefined as a global index measuring the directed information flow between two time series with time-varying properties. Both theoretical analyses and numerical examples demonstrate that Granger causality is a monotonically increasing function of the temporal resolution used in the estimation. This is consistent with the general principle of coarse graining, which causes information loss by smoothing out very fine-scale details in time and space. Our results confirm that the Granger causality at the finer spatio-temporal scales considerably outperforms the traditional approach in terms of an improved consistency between two resting-state scans of the same subject. To optimally estimate the Granger causality, the proposed theoretical framework is implemented through a combination of several approaches, such as dividing the optimal time window and estimating the parameters at the fine temporal and spatial scales. Taken together, our approach provides a novel and robust framework for estimating the Granger causality from fMRI, EEG, and other related data. PMID:23643924

  9. Causality and the stability of parallel flow

    NASA Astrophysics Data System (ADS)

    Chimonas, George

    1991-11-01

    The linearized theory of the stability of parallel flow is formulated in terms of causality theory. In this method the properties of the Fourier spectrum—the disturbances with real frequency ω—provide the stability criteria for a system. In particular, if the Fourier spectrum provides a complete cause-and-effect formulation, the flow is assuredly stable. This single restriction leads to the critical-level theorems for parallel flows in both stably and unstably stratified fluids, Howard's semicircle theorem, the Miles-Howard Richardson-number criterion, an extended semicircle theorem for unstable flows, and several other results concerning instabilities in fluids. The causal approach supersedes group-velocity concepts, and resolves the problems of defining upward- and downward-propagating signals in a rapidly varying medium. It also associates a causal behavior to scattering from a discontinuity or an interface. Causality is examined by subdividing the continuous fluid into a set of homogeneous intervals within which propagation and interfacial scattering can be explicitly computed. As the intervals are reduced toward infinitesimal size the solution for the continuous fluid is obtained.

  10. Support Needs for Canadian Health Providers Responding to Disaster: New Insights from a Grounded Theory Approach

    PubMed Central

    Fahim, Christine; O'Sullivan, Tracey L.; Lane, Dan

    2015-01-01

    Introduction: An earlier descriptive study exploring the various supports available to Canadian health and social service providers who deployed to the 2010 earthquake disaster in Haiti, indicated that when systems are compromised, professionals are at physical, emotional and mental risk during overseas deployment. While these risks are generally well-identified, there is little literature that explores the effectiveness of the supports in place to mitigate this risk. This study provides evidence to inform policy development regarding future disaster relief, and the effectiveness of supports available to responders assisting with international disaster response. Methods: This study follows Strauss and Corbin’s 1990 structured approach to grounded theory to develop a framework for effective disaster support systems. N=21 interviews with Canadian health and social service providers, who deployed to Haiti in response to the 2010 earthquake, were conducted and analyzed. Resulting data were transcribed, coded and analysed for emergent themes. Results and Discussion: Three themes were identified in the data and were used to develop the evolving theory. The interview data indicate that the experiences of responders are determined based on an interaction between the individual’s ‘lens’ or personal expectations, as well as the supports that an organization is able to provide. Therefore, organizations should consider the following factors: experience, expectations, and supports, to tailor a successful support initiative that caters to the needs of the volunteer workforce. PMID:26203399

  11. Bioethical dimensions of cultural psychosomatics: the need for an ethical research approach.

    PubMed

    Lolas, Fernando

    2013-01-01

    Contemporary psychosomatics is a research-based technical discipline and its social power depends on how scientific knowledge is obtained and applied in practice, considering cultural contexts. This article presents the view that the dialogical principles on which bioethical discourse is based are more inclusive than professional ethics and philosophical reflection. The distinction is advanced between rule-guided behavior and norm-justifiable acts (substantiation and justification). The practical implications of good practices in the generation of valid, reliable, generalizable and applicable knowledge are emphasized. For practitioners and researchers, the need to reflect on the distinction between patient and research participant can avoid the therapeutic misunderstanding, a form of abuse of the doctor-patient relationship. In addition, in resource-poor settings, the dilemma presented by the know-do gap (inapplicability of research results due to financial or social constraints) is part of the ethics' realm of the profession. Future prospects include a wider use of research results in practice, but avoidance of the know-do gap (the disparity between what is known and what can be done, particularly in settings with limited resources) requires a synthetic and holistic approach to medical ethics, combining moral reflection, theoretical analysis and empirical data. PMID:23816868

  12. Fossil energy biotechnology: A research needs assessment. [Report recommends biocatalyst approaches

    SciTech Connect

    Finnerty, W.R. )

    1992-04-01

    The Office of Program Analysis of the US Department of Energy commissioned this study to evaluate and prioritize research needs in fossil energy biotechnology. The objectives were to identify research initiatives in biotechnology that offer timely and strategic options for the more efficient and effective uses of the Nation's fossil resource base, particularly the early identification of new and novel applications of biotechnology for the use or conversion of domestic fossil fuels. Fossil energy biotechnology consists of a number of diverse and distinct technologies, all related by the common denominator -- biocatalysis. The expert panel organized 14 technical subjects into three interrelated biotechnology programs: (1) upgrading the fuel value of fossil fuels; (2) bioconversion of fossil feedstocks and refined products to added value chemicals; and, (3) the development of environmental management strategies to minimize and mitigate the release of toxic and hazardous petrochemical wastes. The integration of these programs as viable bioprocessing initiatives proposes an innovative and conceptual principle for the development of a new'' approach to fossil energy biotechnology. This unifying principle is NON-AQUEOUS BIOCATALYSIS. Biocatalysis coupled to conventional chemical catalysis in organic-based media offers bioprocessing options uniquely characterized by the selectivity of biocatalysts plus fast reaction rates and specificity of chemical catalysts.

  13. Theory-Based Causal Induction

    ERIC Educational Resources Information Center

    Griffiths, Thomas L.; Tenenbaum, Joshua B.

    2009-01-01

    Inducing causal relationships from observations is a classic problem in scientific inference, statistics, and machine learning. It is also a central part of human learning, and a task that people perform remarkably well given its notorious difficulties. People can learn causal structure in various settings, from diverse forms of data: observations…

  14. Causal Learning with Local Computations

    ERIC Educational Resources Information Center

    Fernbach, Philip M.; Sloman, Steven A.

    2009-01-01

    The authors proposed and tested a psychological theory of causal structure learning based on local computations. Local computations simplify complex learning problems via cues available on individual trials to update a single causal structure hypothesis. Structural inferences from local computations make minimal demands on memory, require…

  15. The Development of Causal Categorization

    ERIC Educational Resources Information Center

    Hayes, Brett K.; Rehder, Bob

    2012-01-01

    Two experiments examined the impact of causal relations between features on categorization in 5- to 6-year-old children and adults. Participants learned artificial categories containing instances with causally related features and noncausal features. They then selected the most likely category member from a series of novel test pairs.…

  16. Causal Inference in Retrospective Studies.

    ERIC Educational Resources Information Center

    Holland, Paul W.; Rubin, Donald B.

    1988-01-01

    The problem of drawing causal inferences from retrospective case-controlled studies is considered. A model for causal inference in prospective studies is applied to retrospective studies. Limitations of case-controlled studies are formulated concerning relevant parameters that can be estimated in such studies. A coffee-drinking/myocardial…

  17. Causal Inference and Developmental Psychology

    ERIC Educational Resources Information Center

    Foster, E. Michael

    2010-01-01

    Causal inference is of central importance to developmental psychology. Many key questions in the field revolve around improving the lives of children and their families. These include identifying risk factors that if manipulated in some way would foster child development. Such a task inherently involves causal inference: One wants to know whether…

  18. Paradoxical Behavior of Granger Causality

    NASA Astrophysics Data System (ADS)

    Witt, Annette; Battaglia, Demian; Gail, Alexander

    2013-03-01

    Granger causality is a standard tool for the description of directed interaction of network components and is popular in many scientific fields including econometrics, neuroscience and climate science. For time series that can be modeled as bivariate auto-regressive processes we analytically derive an expression for spectrally decomposed Granger Causality (SDGC) and show that this quantity depends only on two out of four groups of model parameters. Then we present examples of such processes whose SDGC expose paradoxical behavior in the sense that causality is high for frequency ranges with low spectral power. For avoiding misinterpretations of Granger causality analysis we propose to complement it by partial spectral analysis. Our findings are illustrated by an example from brain electrophysiology. Finally, we draw implications for the conventional definition of Granger causality. Bernstein Center for Computational Neuroscience Goettingen

  19. On causality of extreme events

    PubMed Central

    2016-01-01

    Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task. We further show how the proposed metric is able to outperform classical causality metrics, provided non-linear relationships are present and large enough data sets are available. PMID:27330866

  20. Do we need a voxel-based approach for LiDAR data in geomorphology?

    NASA Astrophysics Data System (ADS)

    Székely, Balázs; Dorninger, Peter; Faber, Robert; Nothegger, Clemens

    2010-05-01

    Generations of geomorphologists have developed a multi-faceted approach to model the Earth's (and planetary) surface and the corresponding processes. This set of models is based on data, more specifically on conspicuously increasing amount of data. Obviously, all geomorphologists wish themselves more accurate and increasingly high resolution data on, or related to the Earth surface. This evolution also means that the studied boundary is not anymore a single surface; instead it is considered mostly a 2.5D object, sometimes a real 3D object. LiDAR technology can cope with this challenge: the data accuracy and resolution requirements can be fulfilled by applying this method. Although it is yet somewhat still expensive, more and more areas will be scanned, and in some regions the topographic point clouds are already multitemporal (causing of course other types of processing and evaluation problems). It is rather obvious that for certain, geomorphologically very interesting areas very dense and severalfold multitemporal LiDAR data will be available in the near future. These data sets will have various differences concerning the data density, accuracy, data acquisition technique (conventional or full-waveform), and perhaps most importantly, concerning the actual state of the surface. Similar to the satellite imagery integration problems, soon we all have to face with the LiDAR data integration problem. What type of surface or surfaces can be derived from this multitude of data sources with acceptable ambiguity? What conclusions can be drawn from these data that were originally acquired for various other purposes using various acquisition concepts? Will it be advantageous for geomorphic use to have a coverage of the surface with 100-200 points/m² density? Clearly, these data are, if they are once collected, still too expensive not to be integrated for further analyses. Consequently, we need a data reduction concept that effectively decreases the computer capacity needed

  1. CausalTrail: Testing hypothesis using causal Bayesian networks

    PubMed Central

    Trampert, Patrick; Lenhof, Hans-Peter

    2015-01-01

    Summary Causal Bayesian Networks are a special class of Bayesian networks in which the hierarchy directly encodes the causal relationships between the variables. This allows to compute the effect of interventions, which are external changes to the system, caused by e.g. gene knockouts or an administered drug. Whereas numerous packages for constructing causal Bayesian networks are available, hardly any program targeted at downstream analysis exists. In this paper we present CausalTrail, a tool for performing reasoning on causal Bayesian networks using the do-calculus. CausalTrail's features include multiple data import methods, a flexible query language for formulating hypotheses, as well as an intuitive graphical user interface. The program is able to account for missing data and thus can be readily applied in multi-omics settings where it is common that not all measurements are performed for all samples. Availability and Implementation CausalTrail is implemented in C++ using the Boost and Qt5 libraries. It can be obtained from https://github.com/dstoeckel/causaltrail PMID:26913195

  2. Effectively Serving the Needs of Today's Business Student: The Product Life Cycle Approach to Class Organization

    ERIC Educational Resources Information Center

    Eastman, Jacqueline K.; Aviles, Maria; Hanna, Mark

    2012-01-01

    We illustrate a class organization process utilizing the concept of the Product Life Cycle to meet the needs of today's millennial student. In the Introduction stage of a business course, professors need to build structure to encourage commitment. In the Growth stage, professors need to promote the structure through multiple, brief activities that…

  3. Bridging cancer biology and the patients' needs with nanotechnology-based approaches.

    PubMed

    Fonseca, Nuno A; Gregório, Ana C; Valério-Fernandes, Angela; Simões, Sérgio; Moreira, João N

    2014-06-01

    Cancer remains as stressful condition and a leading cause of death in the western world. Actual cornerstone treatments of cancer disease rest as an elusive alternative, offering limited efficacy with extensive secondary effects as a result of severe cytotoxic effects in healthy tissues. The advent of nanotechnology brought the promise to revolutionize many fields including oncology, proposing advanced systems for cancer treatment. Drug delivery systems rest among the most successful examples of nanotechnology. Throughout time they have been able to evolve as a function of an increased understanding from cancer biology and the tumor microenvironment. Marketing of Doxil® unleashed a remarkable impulse in the development of drug delivery systems. Since then, several nanocarriers have been introduced, with aspirations to overrule previous technologies, demonstrating increased therapeutic efficacy besides decreased toxicity. Spatial and temporal targeting to cancer cells has been explored, as well as the use of drug combinations co-encapsulated in the same particle as a mean to take advantage of synergistic interactions in vivo. Importantly, targeted delivery of siRNA for gene silencing therapy has made its way to the clinic for a "first in man" trial using lipid-polymeric-based particles. Focusing in state-of-the-art technology, this review will provide an insightful vision on nanotechnology-based strategies for cancer treatment, approaching them from a tumor biology-driven perspective, since their early EPR-based dawn to the ones that have truly the potential to address unmet medical needs in the field of oncology, upon targeting key cell subpopulations from the tumor microenvironment. PMID:24613464

  4. IITET and shadow TT: an innovative approach to training at the point of need

    NASA Astrophysics Data System (ADS)

    Gross, Andrew; Lopez, Favio; Dirkse, James; Anderson, Darran; Berglie, Stephen; May, Christopher; Harkrider, Susan

    2014-06-01

    The Image Intensification and Thermal Equipment Training (IITET) project is a joint effort between Night Vision and Electronics Sensors Directorate (NVESD) Modeling and Simulation Division (MSD) and the Army Research Institute (ARI) Fort Benning Research Unit. The IITET effort develops a reusable and extensible training architecture that supports the Army Learning Model and trains Manned-Unmanned Teaming (MUM-T) concepts to Shadow Unmanned Aerial Systems (UAS) payload operators. The training challenge of MUM-T during aviation operations is that UAS payload operators traditionally learn few of the scout-reconnaissance skills and coordination appropriate to MUM-T at the schoolhouse. The IITET effort leveraged the simulation experience and capabilities at NVESD and ARI's research to develop a novel payload operator training approach consistent with the Army Learning Model. Based on the training and system requirements, the team researched and identified candidate capabilities in several distinct technology areas. The training capability will support a variety of training missions as well as a full campaign. Data from these missions will be captured in a fully integrated AAR capability, which will provide objective feedback to the user in near-real-time. IITET will be delivered via a combination of browser and video streaming technologies, eliminating the requirement for a client download and reducing user computer system requirements. The result is a novel UAS Payload Operator training capability, nested within an architecture capable of supporting a wide variety of training needs for air and ground tactical platforms and sensors, and potentially several other areas requiring vignette-based serious games training.

  5. Massive dose vitamin A programme in India - Need for a targeted approach

    PubMed Central

    Kapil, Umesh; Sachdev, H.P.S.

    2013-01-01

    The National Prophylaxis Programme against Nutritional Blindness due to vitamin A deficiency (NPPNB due to VAD) was started in 1970 with the specific aim of preventing nutritional blindness due to keratomalacia. The Programme was launched as an urgent remedial measure to combat the unacceptably high magnitude of xerophthalmic blindness in the country seen in the 1950s and 1960s. Clinical VAD has declined drastically during the last 40 years. Also, indicators of child health have shown substantial gains in different States in the country. The prevalence of severe undernutrition has come down significantly. Immunization coverage for measles and other vaccine preventable diseases has improved from 5-7 per cent in early seventies to currently 60-90 per cent, in different States. Similarly, there has been a significant improvement in the overall dietary intake of young children. There has been virtual disappearance of keratomalacia, and a sharp decline in the prevalence of Bitot spots. Prophylactic mega dose administration of vitamin A is primarily advocated because of the claim of 23 per cent reduction in childhood mortality. However, benefits on this scale have been found only in areas with rudimentary health care facilities where clinical deficiency is common, and there is substantial heterogeneity, especially with inclusion of all trials. There is an urgent need for adopting a targeted rather than universal prophylactic mega dose vitamin A supplementation in preschool children. This approach is justified on the basis of currently available evidence documenting a substantial decline in VAD prevalence, substantial heterogeneity and uncertainty about mortality effects in present era with improved health care, and resource constraints with competing priorities. PMID:24135191

  6. Causal sets and conservation laws in tests of Lorentz symmetry

    SciTech Connect

    Mattingly, David

    2008-06-15

    Many of the most important astrophysical tests of Lorentz symmetry also assume that energy momentum of the observed particles is exactly conserved. In the causal set approach to quantum gravity a particular kind of Lorentz symmetry holds but energy-momentum conservation may be violated. We show that incorrectly assuming exact conservation can give rise to a spurious signal of Lorentz symmetry violation for a causal set. However, the size of this spurious signal is much smaller than can be currently detected and hence astrophysical Lorentz symmetry tests as currently performed are safe from causal set induced violations of energy-momentum conservation.

  7. Pharmacotherapeutic intervention in impulsive preschool children: The need for a comprehensive therapeutic approach

    PubMed Central

    2011-01-01

    Impulsive and aggressive behaviour symptoms often are serious problems in children, even already at preschool age. Thus, effective treatment approaches are requested. In this comment pharmacotherapeutic treatment approaches, first of all risperidone, their limitations and alternative psychotherapeutic approaches are outlined. PMID:21489233

  8. Causal Rasch models

    PubMed Central

    Stenner, A. Jackson; Fisher, William P.; Stone, Mark H.; Burdick, Donald S.

    2013-01-01

    Rasch's unidimensional models for measurement show how to connect object measures (e.g., reader abilities), measurement mechanisms (e.g., machine-generated cloze reading items), and observational outcomes (e.g., counts correct on reading instruments). Substantive theory shows what interventions or manipulations to the measurement mechanism can be traded off against a change to the object measure to hold the observed outcome constant. A Rasch model integrated with a substantive theory dictates the form and substance of permissible interventions. Rasch analysis, absent construct theory and an associated specification equation, is a black box in which understanding may be more illusory than not. Finally, the quantitative hypothesis can be tested by comparing theory-based trade-off relations with observed trade-off relations. Only quantitative variables (as measured) support such trade-offs. Note that to test the quantitative hypothesis requires more than manipulation of the algebraic equivalencies in the Rasch model or descriptively fitting data to the model. A causal Rasch model involves experimental intervention/manipulation on either reader ability or text complexity or a conjoint intervention on both simultaneously to yield a successful prediction of the resultant observed outcome (count correct). We conjecture that when this type of manipulation is introduced for individual reader text encounters and model predictions are consistent with observations, the quantitative hypothesis is sustained. PMID:23986726

  9. Generalized Causal Mediation Analysis

    PubMed Central

    Albert, Jeffrey M.; Nelson, Suchitra

    2010-01-01

    Summary The goal of mediation analysis is to assess direct and indirect effects of a treatment or exposure on an outcome. More generally, we may be interested in the context of a causal model as characterized by a directed acyclic graph (DAG), where mediation via a specific path from exposure to outcome may involve an arbitrary number of links (or ‘stages’). Methods for estimating mediation (or pathway) effects are available for a continuous outcome and a continuous mediator related via a linear model, while for a categorical outcome or categorical mediator, methods are usually limited to two-stage mediation. We present a method applicable to multiple stages of mediation and mixed variable types using generalized linear models. We define pathway effects using a potential outcomes framework and present a general formula that provides the effect of exposure through any specified pathway. Some pathway effects are nonidentifiable and their estimation requires an assumption regarding the correlation between counterfactuals. We provide a sensitivity analysis to assess of the impact of this assumption. Confidence intervals for pathway effect estimates are obtained via a bootstrap method. The method is applied to a cohort study of dental caries in very low birth weight adolescents. A simulation study demonstrates low bias of pathway effect estimators and close-to-nominal coverage rates of confidence intervals. We also find low sensitivity to the counterfactual correlation in most scenarios. PMID:21306353

  10. History, causality, and sexology.

    PubMed

    Money, John

    2003-08-01

    In 1896, Krafft-Ebing published Psychopathia Sexualis. Popularly defined as hereditary weakness or taintedness in the family pedigree, degeneracy was called upon as a causal explanation for perversions of the sexual instinct. Although Krafft-Ebing accepted Karl Ulrichs proposal that homosexuality could be innate and probably located in the brain, he paid little attention to neuropathological sexology. Alfred Binet challenged Krafft-Ebing's orthodoxy by explaining fetishism in terms of associative learning, to which Krafft-Ebing's response was that only those with a hereditary taint would be vulnerable. Thus did the venerable nature-nurture antithesis maintain its rhetoric, even to the present day. Krafft-Ebing died too soon to meet the Freudian challenge of endopsychic determinism, and too soon also to encounter the idea of a developmental multivariate outcome of what I have termed the lovemap. Like other brain maps, for example the languagemap, the lovemap requires an intact human brain in which to develop. The personalized content of the lovemap has access to the brain by way of the special senses. PMID:14533017

  11. ["Karoshi" and causal relationships].

    PubMed

    Hamajima, N

    1992-08-01

    This paper aims to introduce a measure for use by physicians for stating the degree of probable causal relationship for "Karoshi", ie, a sudden death from cerebrovascular diseases or ischemic heart diseases under occupational stresses, as well as to give a brief description for legal procedures associated with worker's compensation and civil trial in Japan. It is a well-used measure in epidemiology, "attributable risk percent (AR%)", which can be applied to describe the extent of contribution to "Karoshi" of the excess occupational burdens the deceased worker was forced to bear. Although several standards such as average occupational burdens for the worker, average occupational burdens for an ordinary worker, burdens in a nonoccupational life, and a complete rest, might be considered for the AR% estimation, the average occupational burdens for an ordinary worker should normally be utilized as a standard for worker's compensation. The adoption of AR% could be helpful for courts to make a consistent judgement whether "Karoshi" cases are compensatable or not. PMID:1392028

  12. Space, time, and causality in the human brain.

    PubMed

    Woods, Adam J; Hamilton, Roy H; Kranjec, Alexander; Minhaus, Preet; Bikson, Marom; Yu, Jonathan; Chatterjee, Anjan

    2014-05-15

    The ability to perceive causality is a central human ability constructed from elemental spatial and temporal information present in the environment. Although the nature of causality has captivated philosophers and scientists since antiquity, the neural correlates of causality remain poorly understood. In the present study, we used functional magnetic resonance imaging (fMRI) to generate hypotheses for candidate brain regions related to component processes important for perceptual causality in the human brain: elemental space perception, elemental time perception, and decision-making (Experiment 1; n=16). We then used transcranial direct current stimulation (tDCS) to test neural hypotheses generated from the fMRI experiment (Experiment 2; n=16). In both experiments, participants judged causality in billiard-ball style launching events; a blue ball approaches and contacts a red ball. Spatial and temporal contributions to causal perception were assessed by parametrically varying the spatial linearity and the temporal delays of the movement of the balls. Experiment 1 demonstrated unique patterns of activation correlated with spatial, temporal, and decision-making components of causality perception. Using tDCS, we then tested hypotheses for the specific roles of the parietal and frontal cortices found in the fMRI experiment. Parietal stimulation only decreased participants' perception of causality based on spatial violations, while frontal stimulation made participants less likely to perceive causality based on violations of space and time. Converging results from fMRI and tDCS indicate that parietal cortices contribute to causal perception because of their specific role in processing spatial relations, while the frontal cortices contribute more generally, consistent with their role in decision-making. PMID:24561228

  13. Causal inference and developmental psychology.

    PubMed

    Foster, E Michael

    2010-11-01

    Causal inference is of central importance to developmental psychology. Many key questions in the field revolve around improving the lives of children and their families. These include identifying risk factors that if manipulated in some way would foster child development. Such a task inherently involves causal inference: One wants to know whether the risk factor actually causes outcomes. Random assignment is not possible in many instances, and for that reason, psychologists must rely on observational studies. Such studies identify associations, and causal interpretation of such associations requires additional assumptions. Research in developmental psychology generally has relied on various forms of linear regression, but this methodology has limitations for causal inference. Fortunately, methodological developments in various fields are providing new tools for causal inference-tools that rely on more plausible assumptions. This article describes the limitations of regression for causal inference and describes how new tools might offer better causal inference. This discussion highlights the importance of properly identifying covariates to include (and exclude) from the analysis. This discussion considers the directed acyclic graph for use in accomplishing this task. With the proper covariates having been chosen, many of the available methods rely on the assumption of "ignorability." The article discusses the meaning of ignorability and considers alternatives to this assumption, such as instrumental variables estimation. Finally, the article considers the use of the tools discussed in the context of a specific research question, the effect of family structure on child development. PMID:20677855

  14. Principal stratification in causal inference.

    PubMed

    Frangakis, Constantine E; Rubin, Donald B

    2002-03-01

    Many scientific problems require that treatment comparisons be adjusted for posttreatment variables, but the estimands underlying standard methods are not causal effects. To address this deficiency, we propose a general framework for comparing treatments adjusting for posttreatment variables that yields principal effects based on principal stratification. Principal stratification with respect to a posttreatment variable is a cross-classification of subjects defined by the joint potential values of that posttreatment variable tinder each of the treatments being compared. Principal effects are causal effects within a principal stratum. The key property of principal strata is that they are not affected by treatment assignment and therefore can be used just as any pretreatment covariate. such as age category. As a result, the central property of our principal effects is that they are always causal effects and do not suffer from the complications of standard posttreatment-adjusted estimands. We discuss briefly that such principal causal effects are the link between three recent applications with adjustment for posttreatment variables: (i) treatment noncompliance, (ii) missing outcomes (dropout) following treatment noncompliance. and (iii) censoring by death. We then attack the problem of surrogate or biomarker endpoints, where we show, using principal causal effects, that all current definitions of surrogacy, even when perfectly true, do not generally have the desired interpretation as causal effects of treatment on outcome. We go on to forrmulate estimands based on principal stratification and principal causal effects and show their superiority. PMID:11890317

  15. Causality and quantum criticality in long-range lattice models

    NASA Astrophysics Data System (ADS)

    Maghrebi, Mohammad F.; Gong, Zhe-Xuan; Foss-Feig, Michael; Gorshkov, Alexey V.

    2016-03-01

    Long-range quantum lattice systems often exhibit drastically different behavior than their short-range counterparts. In particular, because they do not satisfy the conditions for the Lieb-Robinson theorem, they need not have an emergent relativistic structure in the form of a light cone. Adopting a field-theoretic approach, we study the one-dimensional transverse-field Ising model with long-range interactions, and a fermionic model with long-range hopping and pairing terms, explore their critical and near-critical behavior, and characterize their response to local perturbations. We deduce the dynamic critical exponent, up to the two-loop order within the renormalization group theory, which we then use to characterize the emergent causal behavior. We show that beyond a critical value of the power-law exponent of the long-range couplings, the dynamics effectively becomes relativistic. Various other critical exponents describing correlations in the ground state, as well as deviations from a linear causal cone, are deduced for a wide range of the power-law exponent.

  16. The Need to Disentangle Key Concepts from Ecosystem-Approach Jargon

    PubMed Central

    WAYLEN, K A; HASTINGS, E J; BANKS, E A; HOLSTEAD, K L; IRVINE, R J; BLACKSTOCK, K L

    2014-01-01

    The ecosystem approach—as endorsed by the Convention on Biological Diversity (CDB) in 2000—is a strategy for holistic, sustainable, and equitable natural resource management, to be implemented via the 12 Malawi Principles. These principles describe the need to manage nature in terms of dynamic ecosystems, while fully engaging with local peoples. It is an ambitious concept. Today, the term is common throughout the research and policy literature on environmental management. However, multiple meanings have been attached to the term, resulting in confusion. We reviewed references to the ecosystem approach from 1957 to 2012 and identified 3 primary uses: as an alternative to ecosystem management or ecosystem-based management; in reference to an integrated and equitable approach to resource management as per the CBD; and as a term signifying a focus on understanding and valuing ecosystem services. Although uses of this term and its variants may overlap in meaning, typically, they do not entirely reflect the ethos of the ecosystem approach as defined by the CBD. For example, there is presently an increasing emphasis on ecosystem services, but focusing on these alone does not promote decentralization of management or use of all forms of knowledge, both of which are integral to the CBD’s concept. We highlight that the Malawi Principles are at risk of being forgotten. To better understand these principles, more effort to implement them is required. Such efforts should be evaluated, ideally with comparative approaches, before allowing the CBD’s concept of holistic and socially engaged management to be abandoned or superseded. It is possible that attempts to implement all 12 principles together will face many challenges, but they may also offer a unique way to promote holistic and equitable governance of natural resources. Therefore, we believe that the CBD’s concept of the ecosystem approach demands more attention. La Necesidad de Desenredar Conceptos Clave del

  17. Applying Causal Discovery to the Output of Climate Models - What Can We Learn from the Causal Signatures?

    NASA Astrophysics Data System (ADS)

    Ebert-Uphoff, I.; Hammerling, D.; Samarasinghe, S.; Baker, A. H.

    2015-12-01

    The framework of causal discovery provides algorithms that seek to identify potential cause-effect relationships from observational data. The output of such algorithms is a graph structure that indicates the potential causal connections between the observed variables. Originally developed for applications in the social sciences and economics, causal discovery has been used with great success in bioinformatics and, most recently, in climate science, primarily to identify interaction patterns between compound climate variables and to track pathways of interactions between different locations around the globe. Here we apply causal discovery to the output data of climate models to learn so-called causal signatures from the data that indicate interactions between the different atmospheric variables. These causal signatures can act like fingerprints for the underlying dynamics and thus serve a variety of diagnostic purposes. We study the use of the causal signatures for three applications: 1) For climate model software verification we suggest to use causal signatures as a means of detecting statistical differences between model runs, thus identifying potential errors and supplementing the Community Earth System Model Ensemble Consistency Testing (CESM-ECT) tool recently developed at NCAR for CESM verification. 2) In the context of data compression of model runs, we will test how much the causal signatures of the model outputs changes after different compression algorithms have been applied. This may result in additional means to determine which type and amount of compression is acceptable. 3) This is the first study applying causal discovery simultaneously to a large number of different atmospheric variables, and in the process of studying the resulting interaction patterns for the two aforementioned applications, we expect to gain some new insights into their relationships from this approach. We will present first results obtained for Applications 1 and 2 above.

  18. Photoemission in strongly correlated crystalline f-electron systems: A need for a new approach

    SciTech Connect

    Arko, A.J.; Joyce, J.J.; Sarrao, J.

    1998-12-01

    The unusual properties of heavy fermion (or heavy electron) materials have sparked an avalanche of research over the last two decades in order to understand the basic phenomena responsible for these properties. Photoelectron spectroscopy (often referred to as PES in the following sections), the most direct measurement of the electronic structure of a material, should in principle be able to shed considerable light on this matter. In general the distinction between a localized and a band-like state is trivially observed in band dispersion. Much of the past work was performed on poly-crystalline samples, scraped in-situ to expose a clean surface for PES. There have since been considerable advances both in the quality of specimens as well as experimental resolution, which raise questions regarding these conclusions. Much of the past work on poly-crystalline samples has been reported in several review articles, most notably Allen et al., and it is not necessary here to review those efforts again, with the exception of subsequent work performed at high resolution. The primary focus of the present review will be on new measurements obtained on single crystals, cleaved or prepared in situ and measured at high resolution, which seem to suggest that agreement with the GS and NCA approximations is less than perfect, and that perhaps the starting models need to be modified, or that even an entirely new approach is called for. Of the promising new models the Periodic Anderson Model is most closely related to the SIM. Indeed, at high temperatures it reverts to the SIM. However, the charge polaron model of Liu (1997) as well as the two-electron band model of Sheng and Cooper (1995) cannot yet be ruled out. Inasmuch as the bulk of the single crystal work was performed by the Los Alamos group, this review will draw heavily on those results. Moreover, since the GS and NCA approximations represent the most comprehensive and widely accepted treatment of heavy fermion PES, it is only

  19. A causal dispositional account of fitness.

    PubMed

    Triviño, Vanessa; Nuño de la Rosa, Laura

    2016-09-01

    The notion of fitness is usually equated to reproductive success. However, this actualist approach presents some difficulties, mainly the explanatory circularity problem, which have lead philosophers of biology to offer alternative definitions in which fitness and reproductive success are distinguished. In this paper, we argue  that none of these alternatives is satisfactory and, inspired by Mumford and Anjum's dispositional theory of causation, we offer a definition of fitness as a causal dispositional property. We argue that, under this framework, the distinctiveness that biologists usually attribute to fitness-namely, the fact that fitness is something different from both the physical traits of an organism and the number of offspring it leaves-can be explained, and the main problems associated with the concept of fitness can be solved. Firstly, we introduce Mumford and Anjum's dispositional theory of causation and present our definition of fitness as a causal disposition. We explain in detail each of the elements involved in our definition, namely: the relationship between fitness and the functional dispositions that compose it, the emergent character of fitness, and the context-sensitivity of fitness. Finally, we explain how fitness and realized fitness, as well as expected and realized fitness are distinguished in our approach to fitness as a causal disposition. PMID:27338570

  20. Cohomology Methods in Causal Perturbation Theory

    NASA Astrophysics Data System (ADS)

    Grigore, D. R.

    2010-01-01

    Various problems in perturbation theory of (quantum) gauge models can be rephrased in the language of cohomology theory. This was already noticed in the functional formulation of perturbative gauge theories. Causal perturbation theory is a fully quantum approach: is works only with the chronological products which are defined as operator-valued distributions in the Fock space of the model. The use of causal perturbation theory leads to similar cohomology problems; the main difference with respect to the functional methods comes from the fact that the gauge transformation of the causal approach is, essentially, the linear part of the non-linear BRST transformation. Using these methods it is possible to give a nice determination of the interaction Lagrangians for gauge models (Yang-Mills and gravitation in the linear approximation); one obtains with this method the unicity of the interaction Lagrangian up to trivial terms. The case of quantum gravity is highly non-trivial and can be generalized with this method to the massive graviton case. Going to higher orders of perturbation theory one finds quantum anomalies. Again the cohomological methods can be used to determine the generic form of these anomalies. Finally, one can investigate the arbitrariness of the chronological products in higher orders and reduce this problem to cohomology methods also.

  1. Basic Human Needs: A Development Planning Approach. AID Discussion Paper No. 38.

    ERIC Educational Resources Information Center

    Crosswell, Michael

    The monograph explores basic needs of all human beings and considers various patterns of growth and development toward meeting these needs on a sustainable basis. The purpose of the study is to improve knowledge of analytical studies, research results, and financial assistance policies among personnel of the Agency for International Development…

  2. A basic need theory approach to problematic Internet use and the mediating effect of psychological distress

    PubMed Central

    Wong, Ting Yat; Yuen, Kenneth S. L.; Li, Wang On

    2015-01-01

    The Internet provides an easily accessible way to meet certain needs. Over-reliance on it leads to problematic use, which studies show can be predicted by psychological distress. Self-determination theory proposes that we all have the basic need for autonomy, competency, and relatedness. This has been shown to explain the motivations behind problematic Internet use. This study hypothesizes that individuals who are psychologically disturbed because their basic needs are not being met are more vulnerable to becoming reliant on the Internet when they seek such needs satisfaction from online activities, and tests a model in which basic needs predict problematic Internet use, fully mediated by psychological distress. Problematic Internet use, psychological distress, and basic needs satisfaction were psychometrically measured in a sample of 229 Hong Kong University students and structural equation modeling was used to test the hypothesized model. All indices showed the model has a good fit. Further, statistical testing supported a mediation effect for psychological distress between needs satisfaction and problematic Internet use. The results extend our understanding of the development and prevention of problematic Internet use based on the framework of self-determination theory. Psychological distress could be used as an early predictor, while preventing and treating problematic Internet use should emphasize the fulfillment of unmet needs. PMID:25642201

  3. High School Teachers' Perspectives on Effective Approaches for Teaching Biology to Students with Special Needs

    ERIC Educational Resources Information Center

    Kos, Agnieszka

    2010-01-01

    The demands of national educational reforms require high school biology teachers to provide high quality instruction to students with and without special needs. The reforms, however, do not provide teachers with adequate teaching strategies to meet the needs of all students in the same context. The purpose of this grounded theory study was to…

  4. Need Supportive Teaching in Practice: A Narrative Analysis in Schools with Contrasting Educational Approaches

    ERIC Educational Resources Information Center

    Stroet, Kim; Opdenakker, Marie-Christine; Minnaert, Alexander

    2015-01-01

    Research on self-determination theory (SDT) has shown that positive learning outcomes accrue in classrooms that support students' needs for autonomy, competence, and relatedness. Studies on what need supportive teaching entails in practice are, however, scarce. In the present study, we aimed to gain in-depth understanding of typical manifestations…

  5. Supervision Strategies and Approaches for Female Parolees: Examining the Link between Unmet Needs and Parolee Outcome

    ERIC Educational Resources Information Center

    Schram, Pamela J.; Koons-Witt, Barbara A.; Williams, Frank P., III; McShane, Marilyn D.

    2006-01-01

    A number of parolees are returning to the community with programming needs that may not have been addressed during their incarceration; these unmet needs may subsequently affect their successful reintegration into the community. Although there is an increasing female parole population, there has been a paucity of research concerning female…

  6. Teaching Music to Students with Special Needs: A Label-Free Approach

    ERIC Educational Resources Information Center

    Hammel, Alice; Hourigan, Ryan

    2011-01-01

    A practical guide & reference manual, "Teaching Music to Students with Special Needs" addresses special needs in the broadest possible sense to equip teachers with proven, research-based curricular strategies that are grounded in both best practice and current special education law. Chapters address the full range of topics and issues music…

  7. Understanding Social and Emotional Needs as an Approach in Developing a Positive Classroom Environment

    ERIC Educational Resources Information Center

    Ozorio, Kristen

    2014-01-01

    The classroom environment is an important aspect of classroom management that concerns many teachers. Properly engaging students in the classroom can foster a positive environment. This study examines social and emotional needs of students and its implications in developing a positive classroom. How can meeting social and emotional needs of…

  8. Temporal Information of Directed Causal Connectivity in Multi-Trial ERP Data using Partial Granger Causality.

    PubMed

    Youssofzadeh, Vahab; Prasad, Girijesh; Naeem, Muhammad; Wong-Lin, KongFatt

    2016-01-01

    Partial Granger causality (PGC) has been applied to analyse causal functional neural connectivity after effectively mitigating confounding influences caused by endogenous latent variables and exogenous environmental inputs. However, it is not known how this connectivity obtained from PGC evolves over time. Furthermore, PGC has yet to be tested on realistic nonlinear neural circuit models and multi-trial event-related potentials (ERPs) data. In this work, we first applied a time-domain PGC technique to evaluate simulated neural circuit models, and demonstrated that the PGC measure is more accurate and robust in detecting connectivity patterns as compared to conditional Granger causality and partial directed coherence, especially when the circuit is intrinsically nonlinear. Moreover, the connectivity in PGC settles faster into a stable and correct configuration over time. After method verification, we applied PGC to reveal the causal connections of ERP trials of a mismatch negativity auditory oddball paradigm. The PGC analysis revealed a significant bilateral but asymmetrical localised activity in the temporal lobe close to the auditory cortex, and causal influences in the frontal, parietal and cingulate cortical areas, consistent with previous studies. Interestingly, the time to reach a stable connectivity configuration (~250–300 ms) coincides with the deviation of ensemble ERPs of oddball from standard tones. Finally, using a sliding time window, we showed higher resolution dynamics of causal connectivity within an ERP trial. In summary, time-domain PGC is promising in deciphering directed functional connectivity in nonlinear and ERP trials accurately, and at a sufficiently early stage. This data-driven approach can reduce computational time, and determine the key architecture for neural circuit modeling. PMID:26470866

  9. Masculinities and young men's sex education needs in Ireland: problematizing client-centred health promotion approaches.

    PubMed

    Hyde, Abbey; Howlett, Etaoine; Drennan, Jonathan; Brady, Dympna

    2005-12-01

    In recent decades, dominant discourses in health promotion have emphasized empowerment, client participation and the notion of people identifying and being facilitated to meet their own health needs. However, there has been little analysis of the concept of 'need' and the possibility, at least, that the fulfillment of some such self-defined needs are not in the interest of social justice and equality. In this article, we present an account of the sex education needs of secondary school pupils from their own perspectives, and problematize the concept of self-identified needs in health education. Twenty-nine focus group interviews were conducted with 226 secondary school pupils in Ireland, and data were subjected to a qualitative analysis. Findings suggested that young men tended to prioritize practical guidance that would provide them with the skills and confidence to take the lead in sexual encounters, and display competence in the act of penetrative sex. We argue that these self-defined sex education needs emanate from a culture of traditional masculinity where, for a male, one's place in the pecking order is derived from one's capacity to conquer, lead and display mastery with regard to sex. In the discussion, we attempt to unpack the notion of clients identifying their own needs and the concept of empowerment as it relates to our data, in the context of gender-based structural inequalities. PMID:16159943

  10. Mood and Memory Research: The Need for a More Wholistic Approach.

    ERIC Educational Resources Information Center

    Kaufman, Judith S.

    The interaction of emotion and cognition has received experimental attention, but the results have generally been weak and sometimes contradictory. Why this work on mood and memory has faltered is discussed, and a more holistic approach to the study of emotion and cognition is proposed. It is argued that a constructivist approach to memory may be…

  11. A Multi-Faceted Formative Assessment Approach: Better Recognising the Learning Needs of Students

    ERIC Educational Resources Information Center

    Jenkins, James O.

    2010-01-01

    Students are increasingly subject to a series of learning pressures that prevent effective engagement in assessment. Thus, the aim of this study was to create a multi-faceted formative assessment approach that better enabled students to engage in the assessment process. A formative assessment approach, consisting of six key initiatives, is…

  12. Strengthening the Focus on Business Results: The Need for Systems Approaches in Organizational Behavior Management

    ERIC Educational Resources Information Center

    Hyten, Cloyd

    2009-01-01

    Current Organizational Behavior Management (OBM) research and practice may be characterized as either behavior focused or results focused. These two approaches stem from different origins and have different characteristics. The behavior-focused approach stems from applied behavior analysis (ABA) methods and emphasizes direct observation of and…

  13. Nonlinear parametric model for Granger causality of time series

    NASA Astrophysics Data System (ADS)

    Marinazzo, Daniele; Pellicoro, Mario; Stramaglia, Sebastiano

    2006-06-01

    The notion of Granger causality between two time series examines if the prediction of one series could be improved by incorporating information of the other. In particular, if the prediction error of the first time series is reduced by including measurements from the second time series, then the second time series is said to have a causal influence on the first one. We propose a radial basis function approach to nonlinear Granger causality. The proposed model is not constrained to be additive in variables from the two time series and can approximate any function of these variables, still being suitable to evaluate causality. Usefulness of this measure of causality is shown in two applications. In the first application, a physiological one, we consider time series of heart rate and blood pressure in congestive heart failure patients and patients affected by sepsis: we find that sepsis patients, unlike congestive heart failure patients, show symmetric causal relationships between the two time series. In the second application, we consider the feedback loop in a model of excitatory and inhibitory neurons: we find that in this system causality measures the combined influence of couplings and membrane time constants.

  14. Schematic Patterns of Causal Evidence.

    ERIC Educational Resources Information Center

    Rholes, William S.; Walters, Jackie

    1982-01-01

    The study was to determine when the patterns of causal evidence proposed by Orvis, Cunningham and Kelly (1975) begin to function as schemata in the attributional process. One hundred forty-four subjects took part in the study. (RH)

  15. Boundary terms for causal sets

    NASA Astrophysics Data System (ADS)

    Buck, Michel; Dowker, Fay; Jubb, Ian; Surya, Sumati

    2015-10-01

    We propose a family of boundary terms for the action of a causal set with a spacelike boundary. We show that in the continuum limit one recovers the Gibbons-Hawking-York boundary term in the mean. We also calculate the continuum limit of the mean causal set action for an Alexandrov interval in flat spacetime. We find that it is equal to the volume of the codimension-2 intersection of the two light-cone boundaries of the interval.

  16. Causality, initial conditions, and inflationary magnetogenesis

    NASA Astrophysics Data System (ADS)

    Tsagas, Christos G.

    2016-05-01

    The post-inflationary evolution of inflation-produced magnetic fields, conventional or not, can change dramatically when two fundamental issues are accounted for. The first is causality, which demands that local physical processes can never affect superhorizon perturbations. The second is the nature of the transition from inflation to reheating and then to the radiation era, which determine the initial conditions at the start of these epochs. Causality implies that inflationary magnetic fields do not freeze into the matter until they have re-entered the causal horizon. The nature of the cosmological transitions and the associated initial conditions, on the other hand, determine the large-scale magnetic evolution after inflation. Put together, the two can slow down the adiabatic magnetic decay on superhorizon scales throughout the Universe's post-inflationary evolution and thus lead to considerably stronger residual magnetic fields. This is "good news" for both the conventional and the nonconventional scenarios of cosmic magnetogenesis. Mechanisms operating outside standard electromagnetism, in particular, do not need to enhance their fields too much during inflation in order to produce seeds that can feed the galactic dynamo today. In fact, even conventionally produced inflationary magnetic fields might be able to sustain the dynamo.

  17. Medical Student Volunteerism Addresses Patients' Social Needs: A Novel Approach to Patient-Centered Care

    PubMed Central

    Onyekere, Chinwe; Ross, Sandra; Namba, Alexa; Ross, Justin C.; Mann, Barry D.

    2016-01-01

    Background: Healthcare providers must be equipped to recognize and address patients' psychosocial needs to improve overall health outcomes. To give future healthcare providers the tools and training necessary to identify and address psychosocial issues, Lankenau Medical Center in partnership with the Philadelphia College of Osteopathic Medicine designed the Medical Student Advocate (MSA) program. Methods: The MSA program places volunteer second-year osteopathic medical students in care coordination teams at Lankenau Medical Associates, a primary care practice serving a diverse patient population in the Philadelphia, PA, region. As active members of the team, MSAs are referred high-risk patients who have resource needs such as food, employment, child care, and transportation. MSAs work collaboratively with patients and the multidisciplinary team to address patients' nonmedical needs. Results: From August 2013 to August 2015, 31 osteopathic medical students volunteered for the MSA program and served 369 patients with 720 identified needs. Faculty and participating medical students report that the MSA program provided an enhanced understanding of the holistic nature of patient care and a comprehensive view of patient needs. Conclusion: The MSA program provides students with a unique educational opportunity that encompasses early exposure to patient interaction, social determinants of health, population health, and interdisciplinary collaboration. Students develop skills to help them build patient relationships, understand the psychosocial factors shaping health outcomes, and engage with other healthcare professionals. This work in the preclinical years provides students with the knowledge to help them perform more effectively in the changing healthcare environment. PMID:27046404

  18. Calculating and Understanding: Formal Models and Causal Explanations in Science, Common Reasoning and Physics Teaching

    NASA Astrophysics Data System (ADS)

    Besson, Ugo

    2010-03-01

    This paper presents an analysis of the different types of reasoning and physical explanation used in science, common thought, and physics teaching. It then reflects on the learning difficulties connected with these various approaches, and suggests some possible didactic strategies. Although causal reasoning occurs very frequently in common thought and daily life, it has long been the subject of debate and criticism among philosophers and scientists. In this paper, I begin by providing a description of some general tendencies of common reasoning that have been identified by didactic research. Thereafter, I briefly discuss the role of causality in science, as well as some different types of explanation employed in the field of physics. I then present some results of a study examining the causal reasoning used by students in solid and fluid mechanics. The differences found between the types of reasoning typical of common thought and those usually proposed during instruction can create learning difficulties and impede student motivation. Many students do not seem satisfied by the mere application of formal laws and functional relations. Instead, they express the need for a causal explanation, a mechanism that allows them to understand how a state of affairs has come about. I discuss few didactic strategies aimed at overcoming these problems, and describe, in general terms, two examples of mechanics teaching sequences which were developed and tested in different contexts. The paper ends with a reflection on the possible role to be played in physics learning by intuitive and imaginative thought, and the use of simple explanatory models based on physical analogies and causal mechanisms.

  19. Physical Education in Further Education. The Need for a Systematic Approach to Curriculum Development. An FEU Occasional Paper.

    ERIC Educational Resources Information Center

    Jackson, Elizabeth; And Others

    This occasional paper describes the development of physical education (PE) in further education (FE) in Great Britain since 1945, and suggests the need for a more systematic approach to curriculum development in this area. Section I reviews the development of PE in FE and identifies major issues and possible future developments. The document…

  20. Implementing a Public Health Approach to Addressing Mental Health Needs in a University Setting: Lessons and Challenges

    ERIC Educational Resources Information Center

    Parcover, Jason; Mays, Sally; McCarthy, Amy

    2015-01-01

    The mental health needs of college students are placing increasing demands on counseling center resources, and traditional outreach efforts may be outdated or incomplete. The public health model provides an approach for reaching more students, decreasing stigma, and addressing mental health concerns before they reach crisis levels. Implementing a…

  1. Coherent Teaching and Need-Based Learning in Science: An Approach to Teach Engineering Students in Basic Physics Courses

    ERIC Educational Resources Information Center

    Kurki-Suonio, T.; Hakola, A.

    2007-01-01

    In the present paper, we propose an alternative, based on constructivism, to the conventional way of teaching basic physics courses at the university level. We call this approach "coherent teaching" and the underlying philosophy of teaching science and engineering "need-based learning". We have been applying this philosophy in practice in a basic…

  2. Analyzing multiple spike trains with nonparametric Granger causality.

    PubMed

    Nedungadi, Aatira G; Rangarajan, Govindan; Jain, Neeraj; Ding, Mingzhou

    2009-08-01

    Simultaneous recordings of spike trains from multiple single neurons are becoming commonplace. Understanding the interaction patterns among these spike trains remains a key research area. A question of interest is the evaluation of information flow between neurons through the analysis of whether one spike train exerts causal influence on another. For continuous-valued time series data, Granger causality has proven an effective method for this purpose. However, the basis for Granger causality estimation is autoregressive data modeling, which is not directly applicable to spike trains. Various filtering options distort the properties of spike trains as point processes. Here we propose a new nonparametric approach to estimate Granger causality directly from the Fourier transforms of spike train data. We validate the method on synthetic spike trains generated by model networks of neurons with known connectivity patterns and then apply it to neurons simultaneously recorded from the thalamus and the primary somatosensory cortex of a squirrel monkey undergoing tactile stimulation. PMID:19137420

  3. Confounding effects of indirect connections on causality estimation.

    PubMed

    Vakorin, Vasily A; Krakovska, Olga A; McIntosh, Anthony R

    2009-10-30

    Addressing the issue of effective connectivity, this study focuses on effects of indirect connections on inferring stable causal relations: partial transfer entropy. We introduce a Granger causality measure based on a multivariate version of transfer entropy. The statistic takes into account the influence of the rest of the network (environment) on observed coupling between two given nodes. This formalism allows us to quantify, for a specific pathway, the total amount of indirect coupling mediated by the environment. We show that partial transfer entropy is a more sensitive technique to identify robust causal relations than its bivariate equivalent. In addition, we demonstrate the confounding effects of the variation in indirect coupling on the detectability of robust causal links. Finally, we consider the problem of model misspecification and its effect on the robustness of the observed connectivity patterns, showing that misspecifying the model may be an issue even for model-free information-theoretic approach. PMID:19628006

  4. Causal tapestries for psychology and physics.

    PubMed

    Sulis, William H

    2012-04-01

    Archetypal dynamics is a formal approach to the modeling of information flow in complex systems used to study emergence. It is grounded in the Fundamental Triad of realisation (system), interpretation (archetype) and representation (formal model). Tapestries play a fundamental role in the framework of archetypal dynamics as a formal representational system. They represent information flow by means of multi layered, recursive, interlinked graphical structures that express both geometry (form or sign) and logic (semantics). This paper presents a detailed mathematical description of a specific tapestry model, the causal tapestry, selected for use in describing behaving systems such as appear in psychology and physics from the standpoint of Process Theory. Causal tapestries express an explicit Lorentz invariant transient now generated by means of a reality game. Observables are represented by tapestry informons while subjective or hidden components (for example intellectual and emotional processes) are incorporated into the reality game that determines the tapestry dynamics. As a specific example, we formulate a random graphical dynamical system using causal tapestries. PMID:22452929

  5. Curvature constraints from the causal entropic principle

    SciTech Connect

    Bozek, Brandon; Albrecht, Andreas; Phillips, Daniel

    2009-07-15

    Current cosmological observations indicate a preference for a cosmological constant that is drastically smaller than what can be explained by conventional particle physics. The causal entropic principle (Bousso et al.) provides an alternative approach to anthropic attempts to predict our observed value of the cosmological constant by calculating the entropy created within a causal diamond. We have extended this work to use the causal entropic principle to predict the preferred curvature within the 'multiverse'. We have found that values larger than {rho}{sub k}=40{rho}{sub m} are disfavored by more than 99.99% peak value at {rho}{sub {lambda}}=7.9x10{sup -123} and {rho}{sub k}=4.3{rho}{sub m} for open universes. For universes that allow only positive curvature or both positive and negative curvature, we find a correlation between curvature and dark energy that leads to an extended region of preferred values. Our universe is found to be disfavored to an extent depending on the priors on curvature. We also provide a comparison to previous anthropic constraints on open universes and discuss future directions for this work.

  6. Reliability of the Granger causality inference

    NASA Astrophysics Data System (ADS)

    Zhou, Douglas; Zhang, Yaoyu; Xiao, Yanyang; Cai, David

    2014-04-01

    How to characterize information flows in physical, biological, and social systems remains a major theoretical challenge. Granger causality (GC) analysis has been widely used to investigate information flow through causal interactions. We address one of the central questions in GC analysis, that is, the reliability of the GC evaluation and its implications for the causal structures extracted by this analysis. Our work reveals that the manner in which a continuous dynamical process is projected or coarse-grained to a discrete process has a profound impact on the reliability of the GC inference, and different sampling may potentially yield completely opposite inferences. This inference hazard is present for both linear and nonlinear processes. We emphasize that there is a hazard of reaching incorrect conclusions about network topologies, even including statistical (such as small-world or scale-free) properties of the networks, when GC analysis is blindly applied to infer the network topology. We demonstrate this using a small-world network for which a drastic loss of small-world attributes occurs in the reconstructed network using the standard GC approach. We further show how to resolve the paradox that the GC analysis seemingly becomes less reliable when more information is incorporated using finer and finer sampling. Finally, we present strategies to overcome these inference artifacts in order to obtain a reliable GC result.

  7. Assessing knowledge skills in the NHS: a training needs analysis approach.

    PubMed

    Hamilton, Seona

    2013-06-01

    This feature discusses the use of a training needs analysis exercise carried out by library staff at the NHS Greater Glasgow & Clyde (NHSGGC) Library Network to support the development of a fit for purpose programme of information skills training. A survey was designed based on a well-known information skills competency framework and used to gain an understanding of the knowledge skills needed by staff and how library training could best support these. The survey received a good response rate and led to the successful writing of a training plan for the Library Network for the delivery of information skills training. H.S. PMID:23692458

  8. On the concept of Bell’s local causality in local classical and quantum theory

    SciTech Connect

    Hofer-Szabó, Gábor; Vecsernyés, Péter

    2015-03-15

    The aim of this paper is to implement Bell’s notion of local causality into a framework, called local physical theory. This framework, based on the axioms of algebraic field theory, is broad enough to integrate both probabilistic and spatiotemporal concepts and also classical and quantum theories. Bell’s original idea of local causality will arise as the classical case of our definition. Classifying local physical theories by whether they obey local primitive causality, a property rendering the dynamics of the theory causal, we then investigate what is needed for a local physical theory to be locally causal. Finally, comparing local causality with the common cause principles and relating both to the Bell inequalities we find a nice parallelism: Bell inequalities cannot be derived neither from local causality nor from a common cause unless the local physical theory is classical or the common cause is commuting, respectively.

  9. Different Kinds of Causality in Event Cognition

    ERIC Educational Resources Information Center

    Radvansky, Gabriel A.; Tamplin, Andrea K.; Armendarez, Joseph; Thompson, Alexis N.

    2014-01-01

    Narrative memory is better for information that is more causally connected and occurs at event boundaries, such as a causal break. However, it is unclear whether there are common or distinct influences of causality. For the event boundaries that arise as a result of causal breaks, the events that follow may subsequently become more causally…

  10. Pediatric Health Fairs: One Approach to the Health Needs of Appalachian Children.

    ERIC Educational Resources Information Center

    Huff, Cynthia O.

    An assessment of the health education needs of children in Tennessee resulted in the initiation of a pediatric health fair by nursing students at Carson-Newman College. The fair was presented to approximately 180 second-grade students in a rural elementary school in East Tennessee. The following activities took place at the exhibits: (1) at the…

  11. User's Guide to Educational Marketing: A Practical Approach for Responding to Community Needs.

    ERIC Educational Resources Information Center

    Portland Community Coll., OR.

    Developed by Portland Community College's (PCC's) Institute for Community Assistance, this guidebook provides checklists of steps that need to be followed in the development and delivery of new, experimental, and custom-designed programs for the community. The booklet begins by explaining the function of the Institute in assisting PCC staff in…

  12. A Needs-Based Approach to the Development of a Diagnostic College English Speaking Test

    ERIC Educational Resources Information Center

    Zhao, Zhongbao

    2014-01-01

    This paper investigated the current situation of oral English teaching, learning, and assessment at the tertiary level in China through needs analysis and explored the implications for the development of a diagnostic speaking test. Through random sampling, the researcher administered both a student questionnaire and a teacher questionnaire to over…

  13. "But, We Don't Have a Library": Exploring Approaches to Addressing Branch Campuses' Library Needs

    ERIC Educational Resources Information Center

    Hostetler, Kirsten; DeSilva, Michele

    2016-01-01

    Librarians at Central Oregon Community College's Barber Library explored how to best serve the needs of three satellite campuses across a large geographic region. While initially intending to start an embedded librarianship program, a pair of surveys showed the relationships and awareness necessary for the foundation of such a program were…

  14. Creativity and the Transformation of Higher Education: The Need for a Black Mountain College Approach

    ERIC Educational Resources Information Center

    Emanuel, Richard C.; Challons-Lipton, Siu

    2013-01-01

    The need for increased creativity in education is currently being proposed in much innovative thinking on higher education as universities are forced to recreate themselves. There are four conditions facing higher education worldwide: alignment, motivation, connection, and direction. Higher education is characterized by a hierarchy of subjects and…

  15. A Mixed-Methods, Multiprofessional Approach to Needs Assessment for Designing Education

    ERIC Educational Resources Information Center

    Moore, Heidi K.; McKeithen, Tom M.; Holthusen, Amy E.

    2011-01-01

    Like most hospital units, neonatal intensive care units (NICUs) are multidisciplinary and team-based. As a result, providing optimal nutritional care to premature infants involves using the knowledge and skills of several types of professionals. Using traditional needs assessment methodologies to effectively understand the educational needs…

  16. Serving the Needs of Challenged Students at a Private Shanghai School: An Action Research Approach

    ERIC Educational Resources Information Center

    Liu, Jerry

    2013-01-01

    This action research started in year 2009 at LIU Shanghai, a private school for children with autism spectrum disorder, to serve the needs of challenged students. The purpose of this qualitative study was to identify the strengths and challenges of the program, plus solicit recommendations from the parents and teachers for making improvements. The…

  17. "Trees and Things That Live in Trees": Three Children with Special Needs Experience the Project Approach

    ERIC Educational Resources Information Center

    Griebling, Susan; Elgas, Peg; Konerman, Rachel

    2015-01-01

    The authors report on research conducted during a project investigation undertaken with preschool children, ages 3-5. The report focuses on three children with special needs and the positive outcomes for each child as they engaged in the project Trees and Things That Live in Trees. Two of the children were diagnosed with developmental delays, and…

  18. A Boosting Approach to eContent Development for Learners with Special Needs

    ERIC Educational Resources Information Center

    Gabrielli, Silvia; Mirabella, Valeria; Kimani, Stephen; Catarci, Tiziana

    2006-01-01

    Of late there has been a growing interest and effort toward meeting the requirements of persons with special needs. However, most of the accessibility standards and guidelines that have been proposed have been developed by adopting a domain independent and often "technical" perspective. Such proposals are therefore often not sufficient to achieve…

  19. Exploring Reading Comprehension Needs of Iranian EAP Students of Health Information Management (HIM): A Triangulated Approach

    ERIC Educational Resources Information Center

    Atai, Mahmood Reza; Nazari, Ogholgol

    2011-01-01

    Discipline-based English for Academic Purposes (EAP) reading programs in Iran are designed to fill the gap between the students' general English reading competence and their ability to read authentic discipline-specific texts. This study attempted to assess target and present reading comprehension needs of EAP students of Health Information…

  20. The House of TESEP and the Communicative Approach: The Special Needs of State English Language Education.

    ERIC Educational Resources Information Center

    Holliday, Adrian

    1994-01-01

    English language teachers around the world are unsure about the appropriateness of the communicative approach (CAP) to the classroom. The problem concerns the nature of technology transfer between instrumentally oriented versus institutionally influenced English language teaching. A broader, rather than narrower version of the CAP can be adapted…

  1. Training and Developing an Age Diverse Workforce in SMEs: The Need for a Strategic Approach

    ERIC Educational Resources Information Center

    Beaver, Graham; Hutchings, Kate

    2005-01-01

    Purpose: The purpose of this paper is to examine the importance of strategic human resource development (HRD) in small and medium-sized enterprises (SMEs) with specific reference to key issues around training, development and education as well as an emerging issue of significance, age diversity management. Design/Methodology/Approach: The approach…

  2. The Guided Reading Approach: A Practical Method to Address Diverse Needs in the Classroom

    ERIC Educational Resources Information Center

    Schaffer, Laura M.; Schirmer, Barbara R.

    2010-01-01

    Many deaf students struggle with learning to read. This is the case nationally as well as at the Michigan School for the Deaf (MSD). In 2006, the elementary teaching staff began working together to implement a change in their reading instruction so their approach would be systematic and consistent across grade levels. With the diverse backgrounds…

  3. Exploring the Ecological Approach Used by RTLBs in Interventions for Students with Learning and Behaviour Needs

    ERIC Educational Resources Information Center

    Sebestian, Sandiyao

    2013-01-01

    The ecological approach, based on the RTLB Toolkit that guides RTLBs in New Zealand, is one of the seven principles used for interventions for students with learning and behaviour concerns. As a result of a paradigm shift moving from a functional limitations perspective to a more inclusive/ecological perspective in 1999, RTLBs have been trained…

  4. Towards an Agile Approach to Adapting Dynamic Collaboration Support to Student Needs

    ERIC Educational Resources Information Center

    Adamson, David; Dyke, Gregory; Jang, Hyeju; Rosé, Carolyn Penstein

    2014-01-01

    This paper investigates the use of conversational agents to scaffold on-line collaborative learning discussions through an approach called Academically Productive Talk (APT). In contrast to past work on dynamic support for collaborative learning, where agents were used to elevate conceptual depth by leading students through directed lines of…

  5. In the Common Good: The Need for a New Approach to Funding Australia's Schools

    ERIC Educational Resources Information Center

    Vickers, Margaret

    2005-01-01

    This article considers evidence which suggests that Australia's current approach to the funding of non-government schools does not serve the common good. Educational provision is now segmented and a majority of private schools have resources that are either moderately or highly superior to those available in public schools. The current funding…

  6. Personal paper: medicine in the 1990s needs a team approach.

    PubMed Central

    English, T.

    1997-01-01

    Health care increasingly emphasises the team approach in which doctors, nurses, and other health workers adapt and develop new skills. Before changes of this kind are widely accepted, however, there must be clarity about the training, status, authority, working relationships, career structure, and remuneration of those who undertake responsibilities well beyond their traditional roles. PMID:9066483

  7. Across Disciplines: A Three Pronged Approach--One Department's Response to Campus-Wide Writing Needs.

    ERIC Educational Resources Information Center

    Christiansen, Pauline

    A west coast community college English department used the following three approaches to seek more effective cross discipline writing awareness: in-house techniques--including topics from various disciplines in classroom assignments; meeting-them-halfway techniques--providing resource people and materials for all instructors and students who…

  8. Discovery of causal mechanisms: Oxidative phosphorylation and the Calvin-Benson cycle.

    PubMed

    Scholl, Raphael; Nickelsen, Kärin

    2015-06-01

    We investigate the context of discovery of two significant achievements of twentieth century biochemistry: the chemiosmotic mechanism of oxidative phosphorylation (proposed in 1961 by Peter Mitchell) and the dark reaction of photosynthesis (elucidated from 1946 to 1954 by Melvin Calvin and Andrew A. Benson). The pursuit of these problems involved discovery strategies such as the transfer, recombination and reversal of previous causal and mechanistic knowledge in biochemistry. We study the operation and scope of these strategies by careful historical analysis, reaching a number of systematic conclusions: (1) even basic strategies can illuminate "hard cases" of scientific discovery that go far beyond simple extrapolation or analogy; (2) the causal-mechanistic approach to discovery permits a middle course between the extremes of a completely substrate-neutral and a completely domain-specific view of scientific discovery; (3) the existing literature on mechanism discovery underemphasizes the role of combinatorial approaches in defining and exploring search spaces of possible problem solutions; (4) there is a subtle interplay between a fine-grained mechanistic and a more coarse-grained causal level of analysis, and both are needed to make discovery processes intelligible. PMID:26013645

  9. Quantitative Risk reduction estimation Tool For Control Systems, Suggested Approach and Research Needs

    SciTech Connect

    Miles McQueen; Wayne Boyer; Mark Flynn; Sam Alessi

    2006-03-01

    For the past year we have applied a variety of risk assessment technologies to evaluate the risk to critical infrastructure from cyber attacks on control systems. More recently, we identified the need for a stand alone control system risk reduction estimation tool to provide owners and operators of control systems with a more useable, reliable, and credible method for managing the risks from cyber attack. Risk is defined as the probability of a successful attack times the value of the resulting loss, typically measured in lives and dollars. Qualitative and ad hoc techniques for measuring risk do not provide sufficient support for cost benefit analyses associated with cyber security mitigation actions. To address the need for better quantitative risk reduction models we surveyed previous quantitative risk assessment research; evaluated currently available tools; developed new quantitative techniques [17] [18]; implemented a prototype analysis tool to demonstrate how such a tool might be used; used the prototype to test a variety of underlying risk calculational engines (e.g. attack tree, attack graph); and identified technical and research needs. We concluded that significant gaps still exist and difficult research problems remain for quantitatively assessing the risk to control system components and networks, but that a useable quantitative risk reduction estimation tool is not beyond reach.

  10. Causality and complexity: the myth of objectivity in science.

    PubMed

    Mikulecky, Donald C

    2007-10-01

    Two distinctly different worldviews dominate today's thinking in science and in the world of ideas outside of science. Using the approach advocated by Robert M. Hutchins, it is possible to see a pattern of interaction between ideas in science and in other spheres such as philosophy, religion, and politics. Instead of compartmentalizing these intellectual activities, it is worthwhile to look for common threads of mutual influence. Robert Rosen has created an approach to scientific epistemology that might seem radical to some. However, it has characteristics that resemble ideas in other fields, in particular in the writings of George Lakoff, Leo Strauss, and George Soros. Historically, the atmosphere at the University of Chicago during Hutchins' presidency gave rise to Rashevsky's relational biology, which Rosen carried forward. Strauss was writing his political philosophy there at the same time. One idea is paramount in all this, and it is Lakoff who gives us the most insight into how the worldviews differ using this idea. The central difference has to do with causality, the fundamental concept that we use to build a worldview. Causal entailment has two distinct forms in Lakoff 's analysis: direct causality and complex causality. Rosen's writings on complexity create a picture of complex causality that is extremely useful in its detail, grounding in the ideas of Aristotle. Strauss asks for a return to the ancients to put philosophy back on track. Lakoff sees the weaknesses in Western philosophy in a similar way, and Rosen provides tools for dealing with the problem. This introduction to the relationships between the thinking of these authors is meant to stimulate further discourse on the role of complex causal entailment in all areas of thought, and how it brings them together in a holistic worldview. The worldview built on complex causality is clearly distinct from that built around simple, direct causality. One important difference is that the impoverished causal

  11. Quantum Supersymmetric Models in the Causal Approach

    NASA Astrophysics Data System (ADS)

    Grigore, Dan-Radu

    2007-04-01

    We consider the massless supersymmetric vector multiplet in a purely quantum framework. First order gauge invariance determines uniquely the interaction Lagrangian as in the case of Yang-Mills models. Going to the second order of perturbation theory produces an anomaly which cannot be eliminated. We make the analysis of the model working only with the component fields.

  12. Use of comparative genomics approaches to characterize interspecies differences in response to environmental chemicals: Challenges, opportunities, and research needs

    SciTech Connect

    Burgess-Herbert, Sarah L.; Euling, Susan Y.

    2013-09-15

    A critical challenge for environmental chemical risk assessment is the characterization and reduction of uncertainties introduced when extrapolating inferences from one species to another. The purpose of this article is to explore the challenges, opportunities, and research needs surrounding the issue of how genomics data and computational and systems level approaches can be applied to inform differences in response to environmental chemical exposure across species. We propose that the data, tools, and evolutionary framework of comparative genomics be adapted to inform interspecies differences in chemical mechanisms of action. We compare and contrast existing approaches, from disciplines as varied as evolutionary biology, systems biology, mathematics, and computer science, that can be used, modified, and combined in new ways to discover and characterize interspecies differences in chemical mechanism of action which, in turn, can be explored for application to risk assessment. We consider how genetic, protein, pathway, and network information can be interrogated from an evolutionary biology perspective to effectively characterize variations in biological processes of toxicological relevance among organisms. We conclude that comparative genomics approaches show promise for characterizing interspecies differences in mechanisms of action, and further, for improving our understanding of the uncertainties inherent in extrapolating inferences across species in both ecological and human health risk assessment. To achieve long-term relevance and consistent use in environmental chemical risk assessment, improved bioinformatics tools, computational methods robust to data gaps, and quantitative approaches for conducting extrapolations across species are critically needed. Specific areas ripe for research to address these needs are recommended.

  13. HIV prevention, structural change and social values: the need for an explicit normative approach

    PubMed Central

    Parkhurst, Justin O

    2012-01-01

    Background The fact that HIV prevention often deals with politicised sexual and drug taking behaviour is well known, but structural HIV prevention interventions in particular can involve alteration of social arrangements over which there may be further contested values at stake. As such, normative frameworks are required to inform HIV prevention decisions and avoid conflicts between social goals. Methods This paper provides a conceptual review and discussion of the normative issues surrounding structural HIV prevention strategies. It applies political and ethical concepts to explore the contested nature of HIV planning and suggests conceptual frameworks to inform future structural HIV responses. Results HIV prevention is an activity that cannot be pursued without making value judgements; it is inherently political. Appeals to health outcomes alone are insufficient when intervention strategies have broader social impacts, or when incidence reduction can be achieved at the expense of other social values such as freedom, equality, or economic growth. This is illustrated by the widespread unacceptability of forced isolation which may be efficacious in preventing spread of infectious agents, but conflicts with other social values. Conclusions While no universal value system exists, the capability approach provides one potential framework to help overcome seeming contradictions or value trade-offs in structural HIV prevention approaches. However, even within the capability approach, valuations must still be made. Making normative values explicit in decision making processes is required to ensure transparency, accountability, and representativeness of the public interest, while ensuring structural HIV prevention efforts align with broader social development goals as well. PMID:22713355

  14. Comparison Analysis: Granger Causality and New Causality and Their Applications to Motor Imagery.

    PubMed

    Hu, Sanqing; Wang, Hui; Zhang, Jianhai; Kong, Wanzeng; Cao, Yu; Kozma, Robert

    2016-07-01

    In this paper we first point out a fatal drawback that the widely used Granger causality (GC) needs to estimate the autoregressive model, which is equivalent to taking a series of backward recursive operations which are infeasible in many irreversible chemical reaction models. Thus, new causality (NC) proposed by Hu et al. (2011) is theoretically shown to be more sensitive to reveal true causality than GC. We then apply GC and NC to motor imagery (MI) which is an important mental process in cognitive neuroscience and psychology and has received growing attention for a long time. We study causality flow during MI using scalp electroencephalograms from nine subjects in Brain-computer interface competition IV held in 2008. We are interested in three regions: Cz (central area of the cerebral cortex), C3 (left area of the cerebral cortex), and C4 (right area of the cerebral cortex) which are considered to be optimal locations for recognizing MI states in the literature. Our results show that: 1) there is strong directional connectivity from Cz to C3/C4 during left- and right-hand MIs based on GC and NC; 2) during left-hand MI, there is directional connectivity from C4 to C3 based on GC and NC; 3) during right-hand MI, there is strong directional connectivity from C3 to C4 which is much clearly revealed by NC than by GC, i.e., NC largely improves the classification rate; and 4) NC is demonstrated to be much more sensitive to reveal causal influence between different brain regions than GC. PMID:26099149

  15. Causal reasoning with mental models

    PubMed Central

    Khemlani, Sangeet S.; Barbey, Aron K.; Johnson-Laird, Philip N.

    2014-01-01

    This paper outlines the model-based theory of causal reasoning. It postulates that the core meanings of causal assertions are deterministic and refer to temporally-ordered sets of possibilities: A causes B to occur means that given A, B occurs, whereas A enables B to occur means that given A, it is possible for B to occur. The paper shows how mental models represent such assertions, and how these models underlie deductive, inductive, and abductive reasoning yielding explanations. It reviews evidence both to corroborate the theory and to account for phenomena sometimes taken to be incompatible with it. Finally, it reviews neuroscience evidence indicating that mental models for causal inference are implemented within lateral prefrontal cortex. PMID:25389398

  16. Causal reasoning with mental models.

    PubMed

    Khemlani, Sangeet S; Barbey, Aron K; Johnson-Laird, Philip N

    2014-01-01

    This paper outlines the model-based theory of causal reasoning. It postulates that the core meanings of causal assertions are deterministic and refer to temporally-ordered sets of possibilities: A causes B to occur means that given A, B occurs, whereas A enables B to occur means that given A, it is possible for B to occur. The paper shows how mental models represent such assertions, and how these models underlie deductive, inductive, and abductive reasoning yielding explanations. It reviews evidence both to corroborate the theory and to account for phenomena sometimes taken to be incompatible with it. Finally, it reviews neuroscience evidence indicating that mental models for causal inference are implemented within lateral prefrontal cortex. PMID:25389398

  17. Fluctuations in relativistic causal hydrodynamics

    NASA Astrophysics Data System (ADS)

    Kumar, Avdhesh; Bhatt, Jitesh R.; Mishra, Ananta P.

    2014-05-01

    Formalism to calculate the hydrodynamic fluctuations by applying the Onsager theory to the relativistic Navier-Stokes equation is already known. In this work, we calculate hydrodynamic fluctuations within the framework of the second order hydrodynamics of Müller, Israel and Stewart and its generalization to the third order. We have also calculated the fluctuations for several other causal hydrodynamical equations. We show that the form for the Onsager-coefficients and form of the correlation functions remain the same as those obtained by the relativistic Navier-Stokes equation and do not depend on any specific model of hydrodynamics. Further we numerically investigate evolution of the correlation function using the one dimensional boost-invariant (Bjorken) flow. We compare the correlation functions obtained using the causal hydrodynamics with the correlation function for the relativistic Navier-Stokes equation. We find that the qualitative behavior of the correlation functions remains the same for all the models of the causal hydrodynamics.

  18. Causal inference from observational data.

    PubMed

    Listl, Stefan; Jürges, Hendrik; Watt, Richard G

    2016-10-01

    Randomized controlled trials have long been considered the 'gold standard' for causal inference in clinical research. In the absence of randomized experiments, identification of reliable intervention points to improve oral health is often perceived as a challenge. But other fields of science, such as social science, have always been challenged by ethical constraints to conducting randomized controlled trials. Methods have been established to make causal inference using observational data, and these methods are becoming increasingly relevant in clinical medicine, health policy and public health research. This study provides an overview of state-of-the-art methods specifically designed for causal inference in observational data, including difference-in-differences (DiD) analyses, instrumental variables (IV), regression discontinuity designs (RDD) and fixed-effects panel data analysis. The described methods may be particularly useful in dental research, not least because of the increasing availability of routinely collected administrative data and electronic health records ('big data'). PMID:27111146

  19. Wormholes, baby universes, and causality

    SciTech Connect

    Visser, M. )

    1990-02-15

    In this paper wormholes defined on a Minkowski signature manifold are considered, both at the classical and quantum levels. It is argued that causality in quantum gravity may best be imposed by restricting the functional integral to include only causal Lorentzian spacetimes. Subject to this assumption, one can put very tight constraints on the quantum behavior of wormholes, their cousins the baby universes, and topology-changing processes in general. Even though topology-changing processes are tightly constrained, this still allows very interesting geometrical (rather than topological) effects. In particular, the laboratory construction of baby universes is {ital not} prohibited provided that the umbilical cord'' is never cut. Methods for relaxing these causality constraints are also discussed.

  20. Testing Quantum Mechanics with Observations of Causally Disconnected Cosmological Events

    NASA Astrophysics Data System (ADS)

    Friedman, Andrew S.; Kaiser, D. I.; Gallicchio, J.; Guth, A. H.

    2014-01-01

    We discuss a thought experiment which would leverage cosmology to test quantum mechanics using astronomical observations. Specifically, we aim to close the "settings-independence" loophole in experimental tests of Bell's inequality by choosing the detector settings (e.g. polarizer orientations) using real-time observations of causally disconnected cosmic sources. This would help close one of the most important remaining Bell test loopholes whereby a local hidden variable theory could mimic the quantum predictions if the experimental settings choices shared even a small correlation due to unknown local causal influences prior to the experiment. The talk will focus on the theoretical cosmology constraints needed to choose optimal sources for such an experiment, describing general conditions for pairs of cosmic events with arbitrary redshifts and angular separations to have shared causal pasts in Friedman-Lemaitre-Robertson-Walker universes with arbitrary curvature, including flat, dark energy dominated, accelerating universes like our own. While causally disjoint patches of the cosmic microwave background radiation at redshift z ~ 1090 could be used to set the detectors, z > 3.65 quasars observed at optical wavelengths are arguably the optimal candidate source pairs using present technology that meet the condition of having no shared causal past since the end of any period of inflation, 13.82 Gyr ago. Results are illustrated for our universe with causal structure animations to help visualize the intersections of past light cones for arbitrary event pairs.

  1. Dhat syndrome: Evolution of concept, current understanding, and need of an integrated approach

    PubMed Central

    Kar, Sujita Kumar; Sarkar, Siddharth

    2015-01-01

    Dhat syndrome has often been construed as a culture-bound sexual neurosis of the Indian subcontinent. Symptoms similar to that of Dhat syndrome has been described in other cultures across different time periods. The present paper looks at the evolution of the concept of Dhat syndrome in India. The review also takes an overview of the current understanding of this syndrome in terms of nosological status as a distinct entity and its “culture-bound” status. The narrative finally attempts to discuss the integrated approach for the treatment of this disorder. PMID:26538854

  2. Reasoning about Causal Relationships: Inferences on Causal Networks

    PubMed Central

    Rottman, Benjamin Margolin; Hastie, Reid

    2013-01-01

    Over the last decade, a normative framework for making causal inferences, Bayesian Probabilistic Causal Networks, has come to dominate psychological studies of inference based on causal relationships. The following causal networks—[X→Y→Z, X←Y→Z, X→Y←Z]—supply answers for questions like, “Suppose both X and Y occur, what is the probability Z occurs?” or “Suppose you intervene and make Y occur, what is the probability Z occurs?” In this review, we provide a tutorial for how normatively to calculate these inferences. Then, we systematically detail the results of behavioral studies comparing human qualitative and quantitative judgments to the normative calculations for many network structures and for several types of inferences on those networks. Overall, when the normative calculations imply that an inference should increase, judgments usually go up; when calculations imply a decrease, judgments usually go down. However, two systematic deviations appear. First, people’s inferences violate the Markov assumption. For example, when inferring Z from the structure X→Y→Z, people think that X is relevant even when Y completely mediates the relationship between X and Z. Second, even when people’s inferences are directionally consistent with the normative calculations, they are often not as sensitive to the parameters and the structure of the network as they should be. We conclude with a discussion of productive directions for future research. PMID:23544658

  3. Re-assessing causal accounts of learnt behavior in rats.

    PubMed

    Burgess, K V; Dwyer, D M; Honey, R C

    2012-04-01

    Rats received either a common-cause (i.e., A→B, A→food) or a causal-chain training scenario (i.e., B→A, A→food) before their tendency to approach the food magazine during the presentation of B was assessed as a function of whether it was preceded by a potential alternative cause. Causal model theory predicts that the influence of an alternative cause should be restricted to the common-cause scenario. In Experiment 1, responding to B was reduced when it occurred after pressing a novel lever during the test phase. This effect was not influenced by the type of training scenario. In Experiment 2, rats were familiarized with the lever prior to test by training it as a potential cause of B. After this treatment, the lever now failed to influence test responding to B. In Experiment 3, rats given common-cause training responded more to B when it followed a cue that had previously been trained as a predictor of B, than when it followed another stimulus. This effect was not apparent in rats that received causal-chain training. This pattern of results is the opposite of that predicted by causal model theory. Thus, in three experiments, the presence of an alternative cause failed to influence test responding in manner consistent with causal model theory. These results undermine the application of causal model theory to rats, but are consistent with associative analyses. PMID:22486754

  4. Overview of tracheal tissue engineering: clinical need drives the laboratory approach.

    PubMed

    Ott, Lindsey M; Weatherly, Robert A; Detamore, Michael S

    2011-08-01

    Breathing is a natural function that most of us do not even think about, but for those who suffer from disease or damage of the trachea, the obstruction of breathing can mean severe restrictions to quality of life or may even be fatal. Replacement and reconstruction of the trachea is one of the most difficult procedures in otolaryngology/head and neck surgery, and also one of the most vital. Previous reviews have focused primarily on clinical perspectives or instead on engineering strategies. However, the current review endeavors to bridge this gap by evaluating engineering approaches in a practical clinical context. For example, although contemporary approaches often include in vitro bioreactor pre-culture, or sub-cutaneous in vivo conditioning, the limitations they present in terms of regulatory approval, cost, additional surgery, and/or risk of infection challenge engineers to develop the next generation of biodegradable/resorbable biomaterials that can be directly implanted in situ. Essentially, the functionality of the replacement is the most important requirement. It must be the correct shape and size, achieve an airtight fit, resist collapse as it is replaced by new tissue, and be non-immunogenic. As we look to the future, there will be no one-size-fits-all solution. PMID:21594727

  5. On The Need for an Information-Based Approach to Evaluating Model Structural Hypotheses (Invited)

    NASA Astrophysics Data System (ADS)

    Gupta, H. V.; Nearing, G. S.; Gong, W.; Clark, M. P.; Vrugt, J. A.

    2013-12-01

    This talk will discuss the problem of building computational models to facilitate understanding and enable testable predictions as a process of 'learning'. Note that there are two aspects to learning, which we might call 'Data Assimilation' and 'Hypothesis Testing', both of which are classically approached as problems of 'Estimation Theory'. In the former, we seek to assimilate information from data, conditional on the assumption that the model structural hypothesis is correct, whereas in the latter we seek to improve our perceptual-conceptual-theoretical view(s) of the world, expressed as model structural hypotheses (assumptions and conjectures), by reconciling them with observations of dynamical systems behavior. Arguably, the second problem is more fundamental, more difficult, and more interesting. This talk will argue that while conventional Estimation Theory (rooted in Maximum Likelihood and Maximum Aposteriori Bayes) provides a valuable theoretical foundation, the strategies we use have become woefully inadequate as models have become progressively more complex. We suggest that the only meaningful way forward is through a formal understanding of the different ways by which 'information' is coded into both model structural hypotheses (as both assumptions and conjectures) and into data, so that a more systematic and powerful approach to testing and improving Earth Systems models, based in diagnostic evaluation, can be achieved. Ultimately, this insight is really a call to formalize, unify and creatively build upon the host of intuitive strategies for model structural assessment that already exist.

  6. The team approach to home-based primary care: restructuring care to meet individual, program, and system needs.

    PubMed

    Reckrey, Jennifer M; Soriano, Theresa A; Hernandez, Cameron R; DeCherrie, Linda V; Chavez, Silvia; Zhang, Meng; Ornstein, Katherine

    2015-02-01

    Team-based models of care are an important way to meet the complex medical and psychosocial needs of the homebound. As part of a quality improvement project to address individual, program, and system needs, a portion of a large, physician-led academic home-based primary care practice was restructured into a team-based model. With support from an office-based nurse practitioner, a dedicated social worker, and a dedicated administrative assistant, physicians were able to care for a larger number of patients. Hospitalizations, readmissions, and patient satisfaction remained the same while physician panel size increased and physician satisfaction improved. The Team Approach is an innovative way to improve interdisciplinary, team-based care through practice restructuring and serves as an example of how other practices can approach the complex task of caring for the homebound. PMID:25645568

  7. The Team Approach to Home-Based Primary Care: Restructuring Care to Meet Patient, Program, and System Needs

    PubMed Central

    Reckrey, Jennifer M.; Soriano, Theresa A.; Hernandez, Cameron R.; DeCherrie, Linda V.; Chavez, Silvia; Zhang, Meng; Ornstein, Katherine

    2016-01-01

    Team-based models of care are an important way to meet the complex medical and psychosocial needs of the homebound. As part of a quality improvement project to address patient, program, and system needs, we restructured a portion of our large, physician-led academic home-based primary care practice into a team-based model. With support from an office-based nurse practitioner, a dedicated social worker, and a dedicated administrative assistant, physicians were able to care for a larger number of patients. Hospitalizations, readmissions, and patient satisfaction remained the same while physician panel size increased and physician satisfaction improved. Our Team Approach is an innovative way to improve interdisciplinary, team-based care though practice restructuring and serves as an example of how other practices can approach the complex task of caring for the homebound. PMID:25645568

  8. Management of Hospital Infection Control in Iran: A Need for Implementation of Multidisciplinary Approach

    PubMed Central

    Mamishi, Setareh; Pourakbari, Babak; Teymuri, Mostafa; Babamahmoodi, Abdolreza; Mahmoudi, Shima

    2014-01-01

    Nosocomial, or hospital-acquired, infections are considered the most common complications affecting hospitalized patients. According to results obtained from studies conducted in the Children Medical Center Hospital, a teaching children's hospital and a tertiary care referral unit in Tehran, Iran, improvements in infection control practices in our hospital seem necessary. The aim of this study was to identify risk management and review potential hospital hazards that may pose a threat to the health as well as safety and welfare of patients in an Iranian referral hospital. Barriers to compliance and poor design of facilities, impractical guidelines and policies, lack of a framework for risk management, failure to apply behavioral-change theory, and insufficient obligation and enforcement by infection control personnel highlight the need of management systems in infection control in our hospital. In addition, surveillance and early reporting of infections, evaluation of risk-based interventions, and production of evidence-based guidelines in our country are recommended. PMID:25379367

  9. [The care needs of women infected with the human papilloma virus: a comprehensive approach].

    PubMed

    Cestari, Maria Elisa Wotzasek; Merighi, Miriam Aparecida Barbosa; Garanhani, Mara Lúcia; Cardeli, Alexandrina Aparecida Maciel; de Jesus, Maria Cristina Pinto; Lopes, Dolores Ferreira de Melo

    2012-10-01

    This study is founded on the phenomenology of Martin Heidegger, with the objective to understand the care needs of women infected with the human papilloma virus. Participants were fourteen women who had been diagnosed with this infection. The guiding questions were: What is it like to have this diagnosis? Tell me your experience, from when you received your diagnosis until today. What has your health care been like? The questions revealed the theme - seeking care as solitude - which showed the importance of the support of family and friends. The presence of the infection as the cause of marital conflicts and separation was another highlighted aspect. The statements showed that there was a sense of resignation after an unsuccessful attempt to find accurate and clear information in order to make assertive decisions. Health interventions for infected women must overcome the traditional models of care, including interventions for health promotion and prevention, with trained professionals who are sensitive to the subjective dimension. PMID:23223722

  10. Identifying Counseling Needs of Nulliparous Adolescent Intrauterine Contraceptive Users: A Qualitative Approach

    PubMed Central

    Brown, Margot K.; Auerswald, Colette; Eyre, Stephen L.; Deardorff, Julianna; Dehlendorf, Christine

    2012-01-01

    Purpose To describe the Intrauterine Contraception (IUC) adoption process among nulliparous adolescents and to identify the role of the medical provider in this trajectory. Methods We conducted semi-structured interviews with a clinic-based sample of twenty nulliparous adolescents (ages 15-24 years) with a history of IUC use. Interviews were analyzed using modified grounded theory and cross-case analysis to reveal a process model for IUC adoption with a focus on the role of the medical provider. Results The model includes the following stages: awareness, initial reaction, information gathering, adoption, and adjustment and reassessment. It is influenced by personal preferences and experiences, friends, family, sexual partner(s), and medical providers. Interactions with medical providers that study participants found helpful in navigating the adoption process included the use of visuals; tailored counseling to address specific contraceptive needs; assurance that IUC discontinuation was an option; information on a wide range of side effects; medical provider self-disclosure regarding use of IUC; and addressing and validating concerns both before and after IUC insertion. Conclusions Nulliparous adolescents in this study described a complex IUC adoption process in which the medical provider plays a substantial supportive role. Findings from this study may be used to counsel and support future nulliparous adolescents regarding IUC use. Implications and Contribution Summary Little is known about nulliparous adolescent use of IUC and the counseling needs of this population. This study offers counseling suggestions for medical providers that they may use to support nulliparous adolescents as they make decisions about IUC use. PMID:23299012

  11. Risk analysis for U.S. offshore wind farms: the need for an integrated approach.

    PubMed

    Staid, Andrea; Guikema, Seth D

    2015-04-01

    Wind power is becoming an increasingly important part of the global energy portfolio, and there is growing interest in developing offshore wind farms in the United States to better utilize this resource. Wind farms have certain environmental benefits, notably near-zero emissions of greenhouse gases, particulates, and other contaminants of concern. However, there are significant challenges ahead in achieving large-scale integration of wind power in the United States, particularly offshore wind. Environmental impacts from wind farms are a concern, and these are subject to a number of on-going studies focused on risks to the environment. However, once a wind farm is built, the farm itself will face a number of risks from a variety of hazards, and managing these risks is critical to the ultimate achievement of long-term reductions in pollutant emissions from clean energy sources such as wind. No integrated framework currently exists for assessing risks to offshore wind farms in the United States, which poses a challenge for wind farm risk management. In this "Perspective", we provide an overview of the risks faced by an offshore wind farm, argue that an integrated framework is needed, and give a preliminary starting point for such a framework to illustrate what it might look like. This is not a final framework; substantial work remains. Our intention here is to highlight the research need in this area in the hope of spurring additional research about the risks to wind farms to complement the substantial amount of on-going research on the risks from wind farms. PMID:25691292

  12. 'Psychotropics caught in a trap' - adopting a screening approach to specific needs.

    PubMed

    Kempf, Jürgen; Traber, Jessica; Auwärter, Volker; Huppertz, Laura M

    2014-10-01

    In the field of forensic toxicology, numerous strategies using different types of LC-MS platforms have been developed to set up an ultimate comprehensive screening method. Despite all this research, the question for the detection of a dedicated set of substances arises quite often in daily routine work. In this project, a screening method for the detection of psychotropic drugs based on the open library concept of a recently developed LC-MS(n) screening approach was developed and the effectiveness of a heated ESI-source was evaluated. To set up an individual spectral library all available data of psychotropics from the Toxtyper™ library was transferred to a new library format and complemented by MS, MS(2) and MS(3) data of additional psychotropic compounds. Precursor masses and retention time information of the library were used to trigger data dependent acquisition of MS(n)-spectra. Serum samples were analysed after alkaline liquid-liquid extraction on a Dionex RSLC (Acclaim™ C18 100×2.1C) coupled to a Bruker amaZon speed ion trap. A conventional ESI-source and an ionBooster™ source (IB) were used for ionization. All other LC and MS parameters were adopted from the original screening approach. Identification and result reporting was carried out by a fully automated software script. This screening method finally contains the individual precursor mass and retention time of 105 psychotropic substances and metabolites. Method evaluation was performed using pooled serum samples fortified with 12 different mixtures containing a total of 99 compounds at low therapeutic concentrations (cLOW and 2×cLOW). The customized method (ESI/IB) led to a higher rate of identifications (92%) - especially at low concentration levels (cLOW) - as the comprehensive screening approach (87%). Results from routine analysis with known intake of psychotropic drugs were confirmed with positive findings, if the concentration range was above or around the assumed limit of detection from

  13. Is a Response to Intervention (RTI) Approach to Preschool Language and Early Literacy Instruction Needed?

    PubMed

    Greenwood, Charles R; Carta, Judith J; Atwater, Jane; Goldstein, Howard; Kaminski, Ruth; McConnell, Scott

    2013-05-01

    Preschool experience plays a role in children's development. However, for programs with language and early literacy goals, the question remains whether or not preschool instructional experiences are sufficiently effective to achieve these goals for all children. In a multisite study, we conducted a process-product description of preschool instruction and children's growth and outcomes in typical programs (i.e., Pre-Kindergarten, Title 1, Head Start, Tuition-Based) using a Response to Intervention (RTI) perspective. Results indicated that (a) students in their preschool year prior to kindergarten made small gains, but students starting the year in lower Tier 2 and 3 performance levels did not close initial skills gaps, (b) variations were noted by program types with varying socio-demographics and instructional processes, and (c) the quality of instruction (Tier 1) received by all was low with room for improvement. Implications for future research on the application of the RTI approach and potential benefits are discussed. PMID:24899769

  14. Global warming and environmental contaminants in aquatic organisms: the need of the etho-toxicology approach.

    PubMed

    Manciocco, Arianna; Calamandrei, Gemma; Alleva, Enrico

    2014-04-01

    Environmental contaminants are associated with a wide spectrum of pathological effects. Temperature increase affects ambient distribution and toxicity of these chemicals in the water environment, representing a potentially emerging problem for aquatic species with short-, medium- and long-term repercussions on human health through the food chain. We assessed peer-reviewed literature, including primary studies, review articles and organizational reports available. We focused on studies concerning toxicity of environmental pollutants within a global warming scenario. Existing knowledge on the effects that the increase of water temperature in a contaminated situation has on physiological mechanisms of aquatic organisms is presented. Altogether we consider the potential consequences for the human beings due to fish and shellfish consumption. Finally, we propose an etho-toxicological approach to study the effects of toxicants in conditions of thermal increase, using aquatic organisms as experimental models under laboratory controlled conditions. PMID:24480426

  15. Cardiovascular surveillance in breast cancer treatment: A more individualized approach is needed.

    PubMed

    Maas, Angela H E M; Ottevanger, Nelleke; Atsma, Femke; Cramer, Maarten J; Leiner, Tim; Poortmans, Philip

    2016-07-01

    Newly developed treatment strategies for breast cancer have reduced mortality rates over the past decades. Patients with breast cancer represent a heterogeneous population. Differences in the severity of the disease require diverse treatment options. Women have distinct individual risk patterns for cardiovascular disease that may affect their susceptibility to cardiotoxicity during therapy. While breast cancer treatment is targeted more on tumor and patient characteristics, a tailored individual approach with early and late cardiosurveillance is not yet implemented in routine care. Newly available cardiac imaging techniques are better suited to the early detection of cardiotoxicity and should be used more often in those patients at highest risk, as the early intervention afforded will improve their quality of life and prognosis. PMID:27180161

  16. Is a Response to Intervention (RTI) Approach to Preschool Language and Early Literacy Instruction Needed?

    PubMed Central

    Greenwood, Charles R.; Carta, Judith J.; Atwater, Jane; Goldstein, Howard; Kaminski, Ruth; McConnell, Scott

    2014-01-01

    Preschool experience plays a role in children's development. However, for programs with language and early literacy goals, the question remains whether or not preschool instructional experiences are sufficiently effective to achieve these goals for all children. In a multisite study, we conducted a process-product description of preschool instruction and children's growth and outcomes in typical programs (i.e., Pre-Kindergarten, Title 1, Head Start, Tuition-Based) using a Response to Intervention (RTI) perspective. Results indicated that (a) students in their preschool year prior to kindergarten made small gains, but students starting the year in lower Tier 2 and 3 performance levels did not close initial skills gaps, (b) variations were noted by program types with varying socio-demographics and instructional processes, and (c) the quality of instruction (Tier 1) received by all was low with room for improvement. Implications for future research on the application of the RTI approach and potential benefits are discussed. PMID:24899769

  17. The need for an interdisciplinary approach in forensic sciences: perspectives from a peculiar case of mummification.

    PubMed

    Ventura, Francesco; Portunato, Federica; Pizzorno, Enrico; Mazzone, Silvana; Verde, Alfredo; Rocca, Gabriele

    2013-05-01

    The finding of a mummified body raises many problems, also because of the limits of the medico-legal investigations in case of mummification. Psychological autopsy and behavioral analysis have demonstrated a significant impact in case of equivocal death. The mummified corpse of a woman was found sealed in a wardrobe during the death investigation of a 36-year-old man, later discovered to be the woman's son. The woman's corpse was well preserved and no external injuries were found. Autopsy could not ascertain the cause of death. The state of the premises and the writings on the walls offered an opportunity to investigate the man's psychological profile and to better understand how the events might have taken place. The role of an accurate investigative analysis of the crime scene is a cornerstone of forensic pathology and the case presented underlies the importance of an interdisciplinary approach in forensic sciences. PMID:23458133

  18. Why we need new approaches to low-dose risk modeling

    SciTech Connect

    Alvarez, J.L.; Seiler, F.A.

    1996-06-01

    The linear no-threshold model for radiation effects was introduced as a conservative model for the design of radiation protection programs. The model has persisted not only as the basis for such programs, but has come to be treated as a dogma and is often confused with scientific fact. In this examination a number of serious problems with the linear no-threshold model of radiation carcinogenesis were demonstrated, many of them invalidating the hypothesis. It was shown that the relative risk formalism did not approach 1 as the dose approaches zero. When morality ratios were used instead, the data in the region below 0.3 Sv were systematically below the predictions of the linear model. It was also shown that the data above 0.3 Sv were of little use in formulating a model at low doses. In addition, these data are valid only for doses accumulated at high dose rates, and there is no scientific justification for using the model in low-dose, low-dose-rate extrapolations for purposes of radiation protection. Further examination of model fits to the Japanese survivor data were attempted. Several such models were fit to the data including an unconstrained linear, linear-square root, and Weibull, all of which fit the data better than the relative risk, linear no-threshold model. These fits were used to demonstrate that the linear model systematically over estimates the risk at low doses in the Japanese survivor data set. It is recommended here that an unbiased re-analysis of the data be undertaken and the results used to construct a new model, based on all pertinent data. This model could then form the basis for managing radiation risks in the appropriate regions of dose and dose rate.

  19. Short bowel syndrome in adults: the need for an interdisciplinary approach and coordinated care.

    PubMed

    Matarese, Laura E; Jeppesen, Palle B; O'Keefe, Stephen J D

    2014-05-01

    Short bowel syndrome (SBS) is a heterogeneous disorder with broad variation in disease severity arising from different types of intestinal resection. The spectrum of malabsorption ranges from intestinal insufficiency to intestinal failure. Individualized patient strategies involving modifications of dietary macro- and micronutrients, fluid, and pharmacologic options are required to maximize health and quality-of-life outcomes and to minimize complications and SBS-associated mortality. Intestinal rehabilitation (IR) is an established but evolving approach to improving patient outcomes by decreasing long-term dependency on parenteral support (PS) for nutrition and fluid requirements. Specialized IR programs employ team-based interdisciplinary approaches to coordinate individualized patient care and treatment management through centralized facilities. Such facilities are often specialized intestinal care centers (ICCs) established at large medical centers. A multifaceted IR program offers the comprehensive interrelated services required by patients with SBS-associated intestinal failure throughout the course of disease. Components of interdisciplinary IR programs should include medical services offering diagnostics and monitoring, pharmacologic management, and symptom and complication control; nutrition services, including dietary modifications and interventions; and supportive psychosocial and educational services. A model of care centered on the IR concept means that long-term patient management, including decisions on long-term PS, is overseen by a member of the specialized care center. Rational, seamless, and timely communication among the patient's network of home-based and ICC healthcare providers is crucial to the success of any IR program. This paradigm shift to specialized IR programs will likely result in improvements across the patient care continuum. PMID:24418899

  20. Multispecialty approach: the need for heart failure disease management for refining cardiac resynchronization therapy.

    PubMed

    Tang, W H Wilson; Boehmer, John; Gras, Daniel

    2012-08-01

    Cardiac resynchronization therapy (CRT) has been proven in clinical trials to be a very effective therapy in appropriate patients. However, although the literature has primarily focused on appropriate implanting techniques and inclusion criteria for CRT devices by electrophysiologists, most patients who receive CRT are managed by their primary care providers with the help of general cardiologists and/or heart failure (HF) specialists. As CRT has been more broadly applied over the past decade, the fragmentation and specialization of care in the current health care system have created challenges in optimizing this otherwise invasive but potentially beneficial intervention in the complex HF patient. Furthermore, cost considerations as well as appropriate follow-up care continue to challenge the optimal application of these devices, particularly when evidence to support multidisciplinary approaches is lacking. The challenge begins with identification of appropriate candidates for CRT, which is an evolving concept due to data emerging from new studies with a wide range of inclusion and exclusion criteria coupled with increasing oversight from providers or even logistical hurdles from patients. Postimplant management practices and procedures are still evolving. The important and so-far unresolved concept of the "nonresponder" to CRT remains largely subjective and is variably defined in the literature, and the lack of understanding of the underlying mechanisms of "nonresponse" continues to challenge long-term management of CRT, even given the recent developments in advanced sensor technologies. Therefore, further investigations into HF disease management with a multispecialty approach, pre-CRT and post-CRT, are warranted. PMID:22521929

  1. Assessing Dynamic Spectral Causality by Lagged Adaptive Directed Transfer Function and Instantaneous Effect Factor

    PubMed Central

    Xu, Haojie; Lu, Yunfeng; Zhu, Shanan

    2014-01-01

    It is of significance to assess the dynamic spectral causality among physiological signals. Several practical estimators adapted from spectral Granger causality have been exploited to track dynamic causality based on the framework of time-varying multivariate autoregressive (tvMVAR) models. The non-zero covariance of the model’s residuals has been used to describe the instantaneous effect phenomenon in some causality estimators. However, for the situations with Gaussian residuals in some autoregressive models, it is challenging to distinguish the directed instantaneous causality if the sufficient prior information about the “causal ordering” is missing. Here, we propose a new algorithm to assess the time-varying causal ordering of tvMVAR model under the assumption that the signals follow the same acyclic causal ordering for all time lags and to estimate the instantaneous effect factor (IEF) value in order to track the dynamic directed instantaneous connectivity. The time-lagged adaptive directed transfer function (ADTF) is also estimated to assess the lagged causality after removing the instantaneous effect. In the present study, we firstly investigated the performance of the causal-ordering estimation algorithm and the accuracy of IEF value. Then, we presented the results of IEF and time-lagged ADTF method by comparing with the conventional ADTF method through simulations of various propagation models. Statistical analysis results suggest that the new algorithm could accurately estimate the causal ordering and give a good estimation of the IEF values in the Gaussian residual conditions. Meanwhile, the time-lagged ADTF approach is also more accurate in estimating the time-lagged dynamic interactions in a complex nervous system after extracting the instantaneous effect. In addition to the simulation studies, we applied the proposed method to estimate the dynamic spectral causality on real visual evoked potential (VEP) data in a human subject. Its usefulness in

  2. Medication reconciliation and therapy management in dialysis-dependent patients: need for a systematic approach.

    PubMed

    Pai, Amy Barton; Cardone, Katie E; Manley, Harold J; St Peter, Wendy L; Shaffer, Rachel; Somers, Michael; Mehrotra, Rajnish

    2013-11-01

    Patients with ESRD undergoing dialysis have highly complex medication regimens and disproportionately higher total cost of care compared with the general Medicare population. As shown by several studies, dialysis-dependent patients are at especially high risk for medication-related problems. Providing medication reconciliation and therapy management services is critically important to avoid costs associated with medication-related problems, such as adverse drug events and hospitalizations in the ESRD population. The Medicare Modernization Act of 2003 included an unfunded mandate stipulating that medication therapy management be offered to high-risk patients enrolled in Medicare Part D. Medication management services are distinct from the dispensing of medications and involve a complete medication review for all disease states. The dialysis facility is a logical coordination center for medication management services, like medication therapy management, and it is likely the first health care facility that a patient will present to after a care transition. A dedicated and adequately trained clinician, such as a pharmacist, is needed to provide consistent, high-quality medication management services. Medication reconciliation and medication management services that could consistently and systematically identify and resolve medication-related problems would be likely to improve ESRD patient outcomes and reduce total cost of care. Herein, this work provides a review of available evidence and recommendations for optimal delivery of medication management services to ESRD patients in a dialysis facility-centered model. PMID:23990162

  3. Recovery of imperiled species under the Endangered Species Act: The need for a new approach

    USGS Publications Warehouse

    Scott, J.M.; Goble, D.D.; Wiens, J.A.; Wilcove, D.S.; Bean, M.; Male, T.

    2005-01-01

    The recovery (delisting) of a threatened or endangered species is often accompanied by the expectation that conservation management of the species will no longer be necessary. However, the magnitude and pace of human impacts on the environment make it unlikely that substantial progress will be made in delisting many species unless the definition of "recovery" includes some form of active management. Preventing delisted species from again being at risk of extinction may require continuing, species-specific management actions. We characterize such species as "conservation-reliant", and suggest that viewing "recovery" as a continuum of states rather than as a simple "recovered/not recovered" dichotomy may enhance our ability to manage such species within the framework of the Endangered Species Act. With ongoing loss of habitat, disruption of natural disturbance regimes, and the increasing impacts of non-native invasive species, it is probable that the number of conservation-reliant species will increase. We propose the development of "recovery management agreements", with legally and biologically defensible contracts that would provide for continu-ing conservation management following delisting. The use of such formalized agreements will facilitate shared management responsibilities between federal wildlife agencies and other federal agencies, and with state, local, and tribal governments, as well as with private entities that have demonstrated the capability to meet the needs of conservation-reliant species. ?? The Ecological Society of America.

  4. Intervention in work-related disability: the need for an integrated approach.

    PubMed

    Greenwood, J G

    1984-01-01

    This paper looks at work-related disability in the United States as it is currently addressed according to the policies and procedures of the Social Security Disability Administration and the Workers' Compensation system. These policies and procedures proceed from a medical model that emphasizes health impairment as the fundamental cause of work-related disability. Thus physicians' evaluations of work-related impairment are the primary basis for administrative disability determinations. Increasing litigation regarding disability determinations and experience with long-term work-related disability suggest that the guiding policies are flawed. Work-related disability is as much a problem of manpower policy as it is one of personal health, but most employers and compensation programs in the United States do not yet respond to it as such. Recommended is a shift from a medical to a socioeconomic frame of reference for work-related disability that would overtly recognize regional variations in the static and dynamic factors of the economy and that would promote return to work and rehabilitation. Political intervention will be necessary. Because cultural values and social relationships are part of the problem, new research is needed in correlates of work-related disability. PMID:6238414

  5. Recursive partitioning for heterogeneous causal effects.

    PubMed

    Athey, Susan; Imbens, Guido

    2016-07-01

    In this paper we propose methods for estimating heterogeneity in causal effects in experimental and observational studies and for conducting hypothesis tests about the magnitude of differences in treatment effects across subsets of the population. We provide a data-driven approach to partition the data into subpopulations that differ in the magnitude of their treatment effects. The approach enables the construction of valid confidence intervals for treatment effects, even with many covariates relative to the sample size, and without "sparsity" assumptions. We propose an "honest" approach to estimation, whereby one sample is used to construct the partition and another to estimate treatment effects for each subpopulation. Our approach builds on regression tree methods, modified to optimize for goodness of fit in treatment effects and to account for honest estimation. Our model selection criterion anticipates that bias will be eliminated by honest estimation and also accounts for the effect of making additional splits on the variance of treatment effect estimates within each subpopulation. We address the challenge that the "ground truth" for a causal effect is not observed for any individual unit, so that standard approaches to cross-validation must be modified. Through a simulation study, we show that for our preferred method honest estimation results in nominal coverage for 90% confidence intervals, whereas coverage ranges between 74% and 84% for nonhonest approaches. Honest estimation requires estimating the model with a smaller sample size; the cost in terms of mean squared error of treatment effects for our preferred method ranges between 7-22%. PMID:27382149

  6. Recursive partitioning for heterogeneous causal effects

    PubMed Central

    Athey, Susan; Imbens, Guido

    2016-01-01

    In this paper we propose methods for estimating heterogeneity in causal effects in experimental and observational studies and for conducting hypothesis tests about the magnitude of differences in treatment effects across subsets of the population. We provide a data-driven approach to partition the data into subpopulations that differ in the magnitude of their treatment effects. The approach enables the construction of valid confidence intervals for treatment effects, even with many covariates relative to the sample size, and without “sparsity” assumptions. We propose an “honest” approach to estimation, whereby one sample is used to construct the partition and another to estimate treatment effects for each subpopulation. Our approach builds on regression tree methods, modified to optimize for goodness of fit in treatment effects and to account for honest estimation. Our model selection criterion anticipates that bias will be eliminated by honest estimation and also accounts for the effect of making additional splits on the variance of treatment effect estimates within each subpopulation. We address the challenge that the “ground truth” for a causal effect is not observed for any individual unit, so that standard approaches to cross-validation must be modified. Through a simulation study, we show that for our preferred method honest estimation results in nominal coverage for 90% confidence intervals, whereas coverage ranges between 74% and 84% for nonhonest approaches. Honest estimation requires estimating the model with a smaller sample size; the cost in terms of mean squared error of treatment effects for our preferred method ranges between 7–22%. PMID:27382149

  7. Causal Models of Literacy Acquisition.

    ERIC Educational Resources Information Center

    Goetz, Ernest T.; And Others

    1992-01-01

    Examines seven articles that employed path analysis to test causal models of the acquisition of literacy or the reading-writing relationship. Reveals that, although such analysis holds promise for a better understanding of the components of literacy, several potential difficulties remain for those attempting to synthesize this body of literature.…

  8. Learning a Theory of Causality

    ERIC Educational Resources Information Center

    Goodman, Noah D.; Ullman, Tomer D.; Tenenbaum, Joshua B.

    2011-01-01

    The very early appearance of abstract knowledge is often taken as evidence for innateness. We explore the relative learning speeds of abstract and specific knowledge within a Bayesian framework and the role for innate structure. We focus on knowledge about causality, seen as a domain-general intuitive theory, and ask whether this knowledge can be…

  9. Causality attribution biases oculomotor responses.

    PubMed

    Badler, Jeremy; Lefèvre, Philippe; Missal, Marcus

    2010-08-01

    When viewing one object move after being struck by another, humans perceive that the action of the first object "caused" the motion of the second, not that the two events occurred independently. Although established as a perceptual and linguistic concept, it is not yet known whether the notion of causality exists as a fundamental, preattentional "Gestalt" that can influence predictive motor processes. Therefore, eye movements of human observers were measured while viewing a display in which a launcher impacted a tool to trigger the motion of a second "reaction" target. The reaction target could move either in the direction predicted by transfer of momentum after the collision ("causal") or in a different direction ("noncausal"), with equal probability. Control trials were also performed with identical target motion, either with a 100 ms time delay between the collision and reactive motion, or without the interposed tool. Subjects made significantly more predictive movements (smooth pursuit and saccades) in the causal direction during standard trials, and smooth pursuit latencies were also shorter overall. These trends were reduced or absent in control trials. In addition, pursuit latencies in the noncausal direction were longer during standard trials than during control trials. The results show that causal context has a strong influence on predictive movements. PMID:20685994

  10. Granger causality and Atlantic hurricanes

    NASA Astrophysics Data System (ADS)

    Elsner, James B.

    2007-08-01

    Atlantic tropical cyclones have been getting stronger recently with a trend that is related to an increase in the late summer/early fall sea-surface temperature over the North Atlantic. Some studies attribute the increasing ocean warmth and hurricane intensity to a natural climate fluctuation, known as the Atlantic Multidecadal Oscillation; others suggest that climate change related to anthropogenic greenhouse gases emissions is the cause. Noting that the only difference between these two hypotheses is the causal connection between global mean near-surface air temperature (GT) and Atlantic sea-surface temperature (SST), the author previously showed how to use statistical tests to examine this hypothesis. Here the author expands on this research. In particular, a more comprehensive explanation of the techniques and additional tests and checks against misspecification are provided. The earlier results are confirmed in showing that preceding GT anomalies have a significant statistical relationship to current SST anomalies but not conversely so that if causality exists between Atlantic SST and global temperature, the causal direction likely goes from GT to SST. The result is robust against a small amount of noise added to the data. Identical tests applied to surrogate time series fail to identify causality as expected. The work underscores the importance of using data models to understand relationships between hurricanes and climate.

  11. Is there a need for alternative approaches in the therapy of cerebrovascular disorders?

    PubMed

    Hartmann, A

    1986-01-01

    Acute ischemia of the brain induces a cascade of biochemical and physiological events. The final consequences depend on the fact whether ischemia is of transient or permanent, total or partial nature. Alteration of extracellular potassium concentration, intracellular calcium and potassium concentration, development of cytotoxic and vasogenic edema, postischemic hyperfusion and no-reflow phenomenon are important factors which decide about the final fate of functional capacity. CO2 reactivity, autoregulation and hemorheology must be considered when therapeutic approaches are used to influence basic flow during ischemic condition. At present there exists no therapy which has been fully accepted and is able to guarantee benefit to the hypoperfused tissue. Since the calcium metabolism is altered by ischemic processes, substances which act on this metabolism might be of value in the treatment of ischemia and its consequences. However, their beneficial effect on cerebral infarction has not been proven yet. In subarachnoid hemorrhage and migraine calcium antagonists are used to prevent and treat ischemia. In epilepsia calcium overload blockers have been tried by one group with promising results. PMID:3758110

  12. Biodiesel exhaust: the need for a systematic approach to health effects research.

    PubMed

    Larcombe, Alexander N; Kicic, Anthony; Mullins, Benjamin J; Knothe, Gerhard

    2015-10-01

    Biodiesel is a generic term for fuel that can be made from virtually any plant or animal oil via transesterification of triglycerides with an alcohol (and usually a catalyst). Biodiesel has received considerable scientific attention in recent years, as it is a renewable resource that is directly able to replace mineral diesel in many engines. Additionally, some countries have mandated a minimum biodiesel content in all diesel fuel sold on environmental grounds. When combusted, biodiesel produces exhaust emissions containing particulate matter, adsorbed chemicals and a range of gases. In many cases, absolute amounts of these pollutants are lower in biodiesel exhaust compared with mineral diesel exhaust, leading to speculation that biodiesel exhaust may be less harmful to health. Additionally, engine performance studies show that the concentrations of these pollutants vary significantly depending on the renewable oil used to make the biodiesel and the ratio of biodiesel to mineral diesel in the fuel mix. Given the strategic and legislative push towards the use of biodiesel in many countries, a concerning possibility is that certain biodiesels may produce exhaust emissions that are more harmful to health than others. This variation suggests that a comprehensive, systematic and comparative approach to assessing the potential for a range of different biodiesel exhausts to affect health is urgently required. Such an assessment could inform biodiesel production priorities, drive research and development into new exhaust treatment technologies, and ultimately minimize the health impacts of biodiesel exhaust exposure. PMID:26179557

  13. IAEA Inspections for Undeclared and Declared Activities: Is a More Robust Approach Needed?

    SciTech Connect

    Mark Schanfein

    2009-07-01

    The United States has long supported a strong international safeguards system and for many years has served as the foremost supplier of technology, equipment, and training to the International Atomic Energy Agency (IAEA). In doing so, it drew in many instances on DOE sponsored R&D and training that was directed towards domestic safeguards and then adapted for IAEA purposes. This was relatively straightforward because of the strong overlap between the development of nuclear material accountancy measures needed for both domestic and international purposes. Two factors have emerged that have made this strong reliance on domestic measures less and less able to be a source of support for the IAEA. One is the shift by the IAEA safeguards system towards detecting undeclared activities. The second is the shift of domestic attention away from nuclear material accountancy and towards physical protection. As a result, a gap in US sponsored R&D and training relevant to international safeguards has developed. The NNSA Next Generation Safeguards Initiative and the DOE NA-22 Safeguards R&D program are intended to help fill this gap and, thereby, permit the U.S. to remain as the pre-eminent supplier of technology for international safeguards purposes. In this context, IAEA challenges have been examined from the perspective of detecting the diversion of nuclear material from declared stocks; detecting undeclared production of nuclear material and activities at locations declared under INFCIRC/153; and detecting undeclared nuclear material and activities elsewhere in a state. Of these, the detection of undeclared nuclear material and activities is, perhaps, the IAEA’s most significant challenge. It is a challenge that even the international community finds difficult to meet because of the scope and the geographic scale of the problem, the technical constraints, the knowledge required, and the significant resources needed to deploy effective systems world-wide (e.g., satellite

  14. Filovirus Research: The Need for an Integrated Approach in Time and Space

    NASA Technical Reports Server (NTRS)

    Pinzon, Jorge E.

    2010-01-01

    The episodic appearance of Ebola virus (EBOV) and Marburg virus (MARV) across central Africa over the last 15 years not only underscores the importance of filoviruses as uniquely virulent agents to both human and wildlife communities but also implies a very complex transmission scenario that must be understood if we are to prevent or mitigate filovirus outbreaks in the future. Efforts of a global network of scientists and healthcare workers have expanded our knowledge of filoviruses to meet the growing threat of Ebola and Marburg hemorrhagic fevers in Africa. In recent decades, several newly emerging diseases have resulted in major threats to both affected communities and global public health. Viruses from wildlife hosts in particular, have exhibited a capability for cross-species transmission (CST), and have caused high-impact diseases in humans Such as Ebola and Marburg hemorrhagic fevers, Nipah and severe acute respiratory syndrome (SAILS). It has been estimated that about 60.3% (Jones et al. 2008) of human infectious diseases are of animal origin (zoonoses) and even some important viral diseases that are traditionally considered of human origin, for example measles and smallpox, may very well have their prehistoric origins in wildlife (Wolfe et al 2007). It maybe logical and prudent therefore, to anticipate that there are other, new filoviruses out there that will cross into humans at some point in time. If we anticipate that these will happen and wish to be prepared for and mitigate this potential, then an understanding of filoviruses as a biologic system in the environment will be essential to that process. We will need to know how the ecological dynamic of CST interacts with a 'new' viruse's evolutionary factors to overcome environmental, demographic and host-specific barriers to transmission and infectivity to humans.

  15. One Health approach to identify research needs in bovine and human babesioses: workshop report

    PubMed Central

    2010-01-01

    Background Babesia are emerging health threats to humans and animals in the United States. A collaborative effort of multiple disciplines to attain optimal health for people, animals and our environment, otherwise known as the One Health concept, was taken during a research workshop held in April 2009 to identify gaps in scientific knowledge regarding babesioses. The impetus for this analysis was the increased risk for outbreaks of bovine babesiosis, also known as Texas cattle fever, associated with the re-infestation of the U.S. by cattle fever ticks. Results The involvement of wildlife in the ecology of cattle fever ticks jeopardizes the ability of state and federal agencies to keep the national herd free of Texas cattle fever. Similarly, there has been a progressive increase in the number of cases of human babesiosis over the past 25 years due to an increase in the white-tailed deer population. Human babesiosis due to cattle-associated Babesia divergens and Babesia divergens-like organisms have begun to appear in residents of the United States. Research needs for human and bovine babesioses were identified and are presented herein. Conclusions The translation of this research is expected to provide veterinary and public health systems with the tools to mitigate the impact of bovine and human babesioses. However, economic, political, and social commitments are urgently required, including increased national funding for animal and human Babesia research, to prevent the re-establishment of cattle fever ticks and the increasing problem of human babesiosis in the United States. PMID:20377902

  16. [Need for alternative approaches in the evaluation of new antibacterial antibiotics].

    PubMed

    Trémolières, F; Garraffo, R; Lortholary, O

    2005-08-01

    The golden age of antibacterial antibiotics extend from year 1941 to the 1990s decade. At that time, something like an earth quake occurred: from the thirty molecules or so whose development was being achieved or was already marketed, only three were put on the French market, and faced the greatest difficulties to be prescribed by practicians, because: the knights of good practice want a strict limitation of their use to precise indications; the pharmaceutical companies find that the return on investment is almost impossible; the prescribers are stunned by the inconsistency between the MAs, the advances in science and the health economic authorities advices which claim that these products are not very interesting; the research for new antibiotics is stalling; thus, for the first time in 60 years, an iconoclastic question arises: do we need new antibiotics? However, while the debate is raging, many of us think "yes we do", as it is a duty to anticipate today the consequences of tomorrow's bacterial resistances. This paper presents three types of propositions to optimise the development of future molecules: sharpening of the data concerning preclinical security for a better predicting of both the activity and the toxicity; improvement in performances and organization of clinical trials, which implicates to reconsider some of the present methodological rules; inclusion in the evaluation data of some relevant and new features measuring the anti-bacterial activity while taking into account the present and future bacterial resistances. The development of new concepts to develop new drugs which would be active against tomorrow's bacteria compels us to manage in a new fashion today's systems, which have reached their own limits. PMID:16245387

  17. Whole-grain dietary recommendations: the need for a unified global approach.

    PubMed

    Seal, Chris J; Nugent, Anne P; Tee, E-Siong; Thielecke, Frank

    2016-06-01

    Increased whole-grain (WG) consumption reduces the risk of CVD, type 2 diabetes and some cancers, is related to reduced body weight and weight gain and is related to improved intestinal health. Definitions of 'WG' and 'WG food' are proposed and used in some countries but are not consistent. Many countries promote WG consumption, but the emphasis given and the messages used vary. We surveyed dietary recommendations of fifty-three countries for mentions of WG to assess the extent, rationale and diversity in emphasis and wording of any recommendations. If present, recommendations were classified as either 'primary', where the recommendation was specific for WG, or 'secondary', where recommendations were made in order to achieve another (primary) target, most often dietary fibre intake. In total, 127 organisations were screened, including government, non-governmental organisations, charities and professional bodies, the WHO and European Food Safety Authority, of which forty-nine including WHO provide a WG intake recommendation. Recommendations ranged from 'specific' with specified target amounts (e.g. x g WG/d), 'semi-quantitative' where intake was linked to intake of cereal/carbohydrate foods with proportions of WG suggested (e.g. x servings of cereals of which y servings should be WG) to 'non-specific' based on 'eating more' WG or 'choosing WG where possible'. This lack of a harmonised message may result in confusion for the consumer, lessen the impact of public health messages and pose barriers to trade in the food industry. A science-based consensus or expert opinion on WG recommendations is needed, with a global reach to guide public health decision making and increase WG consumption globally. PMID:27082494

  18. The need for an organized approach for Government Medical Insurance Programs in the Commonwealth of Virginia.

    PubMed

    Edlich, Richard F

    2005-01-01

    The Commonwealth of Virginia has a disorganized approach to enrolling their retired faculty in Medicare Supplement Insurance Programs. An organized approach to establishing Medicare Supplemental Insurance for retired University faculty should include the following administrative changes to correct this potential health-care crisis for retired state faculty members. First, the ombudsman for human resources for the state universities must receive educational programs that prepare the retired faculty members over the age of 65 to select the corporate insurance policy from Anthem Blue Cross/Blue Shield Insurance Company. Included in this educational program should be a review of the Advantage 65 Member Handbook. Second, they must point out to the faculty member that they are receiving a CORPORATE insurance policy rather than an individual insurance policy from Anthem Blue Cross/Blue Shield Insurance Company. They must provide the telephone numbers of the Anthem Blue Cross/Blue Shield offices in Roanoke, Virginia. Concomitantly, they must send the name and address of the faculty member to the Commonwealth of Virginia Department of Human Resource Management. They should inform the faculty member that the Commonwealth of Virginia Department of Human Resource Management will be sending them newsletters that outline any changes in the corporate insurance policy that they coordinate with the Anthem Blue Cross/Blue Shield Insurance Company. The Commonwealth of Virginia Department of Human Resource Management must take on some new responsibilities in their efforts to coordinate health-care coverage of the retired faculty over the age of 65. First, they must have a computer registry of all corporate health-care policies of the individual faculty members to ensure that newsletters are being sent to them. Ideally, this agency should have a computerized system that allows it to send out its newsletter update by email to those retired faculty members who have computers. They should

  19. A holistic approach to chronic pain management that involves all stakeholders: change is needed.

    PubMed

    Kress, Hans-Georg; Aldington, Dominic; Alon, Eli; Coaccioli, Stefano; Collett, Beverly; Coluzzi, Flaminia; Huygen, Frank; Jaksch, Wolfgang; Kalso, Eija; Kocot-Kępska, Magdalena; Mangas, Ana Cristina; Ferri, Cesar Margarit; Mavrocordatos, Philippe; Morlion, Bart; Müller-Schwefe, Gerhard; Nicolaou, Andrew; Hernández, Concepción Pérez; Sichère, Patrick

    2015-01-01

    Chronic pain affects a large proportion of the population, imposing significant individual distress and a considerable burden on society, yet treatment is not always instituted and/or adequate. Comprehensive multidisciplinary management based on the biopsychosocial model of pain has been shown to be clinically effective and cost-efficient, but is not widely available. A literature review of stakeholder groups revealed many reasons for this, including: i) many patients believe healthcare professionals lack relevant knowledge, and consultations are rushed, ii) general practitioners consider that pain management has a low priority and is under-resourced, iii) pain specialists cite non-adherence to evidence-based treatment, sub-optimal prescribing, and chronic pain not being regarded as a disease in its own right, iv) nurses', pharmacists' and physiotherapists' skills are not fully utilized, and v) psychological therapy is employed infrequently and often too late. Many of the issues relating to physicians could be addressed by improving medical training, both at undergraduate and postgraduate levels - for example, by making pain medicine a compulsory core subject of the undergraduate medical curriculum. This would improve physician/patient communication, increase the use of standardized pain assessment tools, and allow more patients to participate in treatment decisions. Patient care would also benefit from improved training for other multidisciplinary team members; for example, nurses could provide counseling and follow-up support, psychologists offer coping skills training, and physiotherapists have a greater role in rehabilitation. Equally important measures include the widespread adoption of a patient-centered approach, chronic pain being recognized as a disease in its own right, and the development of universal guidelines for managing chronic non-cancer pain. Perhaps the greatest barrier to improvement is lack of political will at both national and international

  20. Supporting culturally and linguistically diverse children with speech, language and communication needs: Overarching principles, individual approaches.

    PubMed

    Verdon, Sarah; McLeod, Sharynne; Wong, Sandie

    2015-01-01

    Speech-language pathologists (SLPs) are working with an increasing number of families from culturally and linguistically diverse backgrounds as the world's population continues to become more internationally mobile. The heterogeneity of these diverse populations makes it impossible to identify and document a one size fits all strategy for working with culturally and linguistically diverse families. This paper explores approaches to practice by SLPs identified as specialising in multilingual and multicultural practice in culturally and linguistically diverse contexts from around the world. Data were obtained from ethnographic observation of 14 sites in 5 countries on 4 continents. The sites included hospital settings, university clinics, school-based settings, private practices and Indigenous community-based services. There were 652 individual artefacts collected from the sites which included interview transcripts, photographs, videos, narrative reflections, informal and formal field notes. The data were analysed using Cultural-Historical Activity Theory (Engeström, 1987). From the analysis six overarching Principles of Culturally Competent Practice (PCCP) were identified. These were: (1) identification of culturally appropriate and mutually motivating therapy goals, (2) knowledge of languages and culture, (3) use of culturally appropriate resources, (4) consideration of the cultural, social and political context, (5) consultation with families and communities, and (6) collaboration between professionals. These overarching principles align with the six position statements developed by the International Expert Panel on Multilingual Children's Speech (2012) which aim to enhance the cultural competence of speech pathologists and their practice. The international examples provided in the current study demonstrate the individualised ways that these overarching principles are enacted in a range of different organisational, social, cultural and political contexts

  1. Causal Inference for a Population of Causally Connected Units

    PubMed Central

    van der Laan, Mark J.

    2015-01-01

    Suppose that we observe a population of causally connected units. On each unit at each time-point on a grid we observe a set of other units the unit is potentially connected with, and a unit-specific longitudinal data structure consisting of baseline and time-dependent covariates, a time-dependent treatment, and a final outcome of interest. The target quantity of interest is defined as the mean outcome for this group of units if the exposures of the units would be probabilistically assigned according to a known specified mechanism, where the latter is called a stochastic intervention. Causal effects of interest are defined as contrasts of the mean of the unit-specific outcomes under different stochastic interventions one wishes to evaluate. This covers a large range of estimation problems from independent units, independent clusters of units, and a single cluster of units in which each unit has a limited number of connections to other units. The allowed dependence includes treatment allocation in response to data on multiple units and so called causal interference as special cases. We present a few motivating classes of examples, propose a structural causal model, define the desired causal quantities, address the identification of these quantities from the observed data, and define maximum likelihood based estimators based on cross-validation. In particular, we present maximum likelihood based super-learning for this network data. Nonetheless, such smoothed/regularized maximum likelihood estimators are not targeted and will thereby be overly bias w.r.t. the target parameter, and, as a consequence, generally not result in asymptotically normally distributed estimators of the statistical target parameter. To formally develop estimation theory, we focus on the simpler case in which the longitudinal data structure is a point-treatment data structure. We formulate a novel targeted maximum likelihood estimator of this estimand and show that the double robustness of the

  2. Causal Conceptions in Social Explanation and Moral Evaluation: A Historical Tour.

    PubMed

    Alicke, Mark D; Mandel, David R; Hilton, Denis J; Gerstenberg, Tobias; Lagnado, David A

    2015-11-01

    Understanding the causes of human behavior is essential for advancing one's interests and for coordinating social relations. The scientific study of how people arrive at such understandings or explanations has unfolded in four distinguishable epochs in psychology, each characterized by a different metaphor that researchers have used to represent how people think as they attribute causality and blame to other individuals. The first epoch was guided by an "intuitive scientist" metaphor, which emphasized whether observers perceived behavior to be caused by the unique tendencies of the actor or by common reactions to the requirements of the situation. This metaphor was displaced in the second epoch by an "intuitive lawyer" depiction that focused on the need to hold people responsible for their misdeeds. The third epoch was dominated by theories of counterfactual thinking, which conveyed a "person as reconstructor" approach that emphasized the antecedents and consequences of imagining alternatives to events, especially harmful ones. With the current upsurge in moral psychology, the fourth epoch emphasizes the moral-evaluative aspect of causal judgment, reflected in a "person as moralist" metaphor. By tracing the progression from the person-environment distinction in early attribution theories to present concerns with moral judgment, our goal is to clarify how causal constructs have been used, how they relate to one another, and what unique attributional problems each addresses. PMID:26581736

  3. Causal Inference and Observational Research: The Utility of Twins

    PubMed Central

    McGue, Matt; Osler, Merete; Christensen, Kaare

    2011-01-01

    Valid causal inference is central to progress in theoretical and applied psychology. Although the randomized experiment is widely considered the gold standard for determining whether a given exposure increases the likelihood of some specified outcome, experiments are not always feasible and in some cases can result in biased estimates of causal effects. Alternatively, standard observational approaches are limited by the possibility of confounding, reverse causation, and the nonrandom distribution of exposure (i.e., selection). We describe the counterfactual model of causation and apply it to the challenges of causal inference in observational research, with a particular focus on aging. We argue that the study of twin pairs discordant on exposure, and in particular discordant monozygotic twins, provides a useful analog to the idealized counterfactual design. A review of discordant-twin studies in aging reveals that they are consistent with, but do not unambiguously establish, a causal effect of lifestyle factors on important late-life outcomes. Nonetheless, the existing studies are few in number and have clear limitations that have not always been considered in interpreting their results. It is concluded that twin researchers could make greater use of the discordant-twin design as one approach to strengthen causal inferences in observational research. PMID:21593989

  4. Pollutant fates in fluvial systems: on need of individual approach to each case study

    NASA Astrophysics Data System (ADS)

    Matys Grygar, Tomas; Elznicova, Jitka; Novakova, Tereza

    2015-04-01

    deposition in a channel belt and subsequent secondary pollution via physical mobilisation, most pollution storing in the floodplain in a surprisingly heterogeneous manner - in hotspots with a size comparable to fragments of abandoned channels (from a few to few tens of metres). The hotspots are hence best revealed by well-designed field analysis using portable instruments (gamma spectrometry or XRF). The Litavka is specific because most pollution is in its floodplain in the form of anthropogenic alluvium, a very thick vertical accretion body of "artificial" material added to the river system in the amount exceeding its normal transport capacity. That situation favours secondary pollution by chemical mobilisation of pollutants under low river discharges revealed by geochemical analysis. Our case studies show that simple "rules" such as continuous decay of pollutant concentrations downstream from the pollution source, existence of a continuous blanket of polluted overbank fines in floodplain, simple change of the pollution extent with growing distance from the river channel and as a consequence of extreme floods, or simple recipes such as low-density sampling to trace point pollution sources are too simplistic to be applicable in real polluted fluvial systems. Each river system represents a nearly unique combination of individual geomorphic processes, and each pollution has been specific by the mode how it entered the fluvial system. We will not offer "magic tools" in our contribution. In literature we can find all pieces we need for the jigsaw puzzle - pollutants fates in fluvial systems. The question is why so rarely researchers put them together. We would like to encourage them to do so.

  5. Causal assessment of pharmaceutical treatments: why standards of evidence should not be the same for benefits and harms?

    PubMed

    Osimani, Barbara; Mignini, Fiorenzo

    2015-01-01

    It is increasingly acknowledged both among epidemiologists and regulators that the assessment of pharmaceutical harm requires specific methodological approaches that cannot simply duplicate those developed for testing efficacy. However, this intuition lacks sound epistemic bases and delivers ad hoc advice. This paper explains why the same methods of scientific inference do not fare equally well for efficacy and safety assessment by tracing them back to their epistemic foundations. To illustrate this, Cartwright's distinction into clinching and vouching methods is adopted and a series of reasons is provided for preferring the latter to the former: (1) the need to take into account all available knowledge and integrate it with incoming data; (2) the awareness that a latent unknown risk may always change the safety profile of a given drug (precautionary principle); (3) cumulative learning over time; (4) requirement of probabilistic causal assessment to allow decision under uncertainty; (5) impartiality; and (6) limited and local information provided by randomised controlled trials. Subsequently, the clinchers/vouchers distinction is applied to a case study concerning the debated causal association between paracetamol and asthma. This study illustrates the tension between implicit epistemologies adopted in evaluating evidence and causality; furthermore, it also shows that discounting causal evidence may be a result of unacknowledged low priors or lack of valid alternative options. We conclude with a presentation of the changing landscape in pharmacology and the trend towards an increased use of Bayesian tools for assessment of harms. PMID:25519721

  6. Relating Granger causality to long-term causal effects

    NASA Astrophysics Data System (ADS)

    Smirnov, Dmitry A.; Mokhov, Igor I.

    2015-10-01

    In estimation of causal couplings between observed processes, it is important to characterize coupling roles at various time scales. The widely used Granger causality reflects short-term effects: it shows how strongly perturbations of a current state of one process affect near future states of another process, and it quantifies that via prediction improvement (PI) in autoregressive models. However, it is often more important to evaluate the effects of coupling on long-term statistics, e.g., to find out how strongly the presence of coupling changes the variance of a driven process as compared to an uncoupled case. No general relationships between Granger causality and such long-term effects are known. Here, we pose the problem of relating these two types of coupling characteristics, and we solve it for a class of stochastic systems. Namely, for overdamped linear oscillators, we rigorously derive that the above long-term effect is proportional to the short-term effects, with the proportionality coefficient depending on the prediction interval and relaxation times. We reveal that this coefficient is typically considerably greater than unity so that small normalized PI values may well correspond to quite large long-term effects of coupling. The applicability of the derived relationship to wider classes of systems, its limitations, and its value for further research are discussed. To give a real-world example, we analyze couplings between large-scale climatic processes related to sea surface temperature variations in equatorial Pacific and North Atlantic regions.

  7. Causal Agency Theory: Reconceptualizing a Functional Model of Self-Determination

    ERIC Educational Resources Information Center

    Shogren, Karrie A.; Wehmeyer, Michael L.; Palmer, Susan B.; Forber-Pratt, Anjali J.; Little, Todd J.; Lopez, Shane

    2015-01-01

    This paper introduces Causal Agency Theory, an extension of the functional model of self-determination. Causal Agency Theory addresses the need for interventions and assessments pertaining to selfdetermination for all students and incorporates the significant advances in understanding of disability and in the field of positive psychology since the…

  8. Causal diffusion and the survival of charge fluctuations in nuclear collisions

    SciTech Connect

    Aziz, Mohamed Abdel; Gavin, Sean

    2004-09-01

    Diffusion may obliterate fluctuation signals of the QCD phase transition in nuclear collisions at SPS and RHIC energies. We propose a hyperbolic diffusion equation to study the dissipation of net charge fluctuations. This equation is needed in a relativistic context, because the classic parabolic diffusion equation violates causality. We find that causality substantially limits the extent to which diffusion can dissipate these fluctuations.

  9. Constraints on Children's Judgments of Magical Causality

    ERIC Educational Resources Information Center

    Woolley, Jacqueline D.; Browne, Cheryl A.; Boerger, Elizabeth A.

    2006-01-01

    In 3 studies we addressed the operation of constraints on children's causal judgments. Our primary focus was whether children's beliefs about magical causality, specifically wishing, are constrained by features that govern the attribution of ordinary causality. In Experiment 1, children witnessed situations in which a confederate's wish appeared…

  10. Designing Effective Supports for Causal Reasoning

    ERIC Educational Resources Information Center

    Jonassen, David H.; Ionas, Ioan Gelu

    2008-01-01

    Causal reasoning represents one of the most basic and important cognitive processes that underpin all higher-order activities, such as conceptual understanding and problem solving. Hume called causality the "cement of the universe" [Hume (1739/2000). Causal reasoning is required for making predictions, drawing implications and inferences, and…

  11. Representing Personal Determinants in Causal Structures.

    ERIC Educational Resources Information Center

    Bandura, Albert

    1984-01-01

    Responds to Staddon's critique of the author's earlier article and addresses issues raised by Staddon's (1984) alternative models of causality. The author argues that it is not the formalizability of causal processes that is the issue but whether cognitive determinants of behavior are reducible to past stimulus inputs in causal structures.…

  12. Expectations and Interpretations during Causal Learning

    ERIC Educational Resources Information Center

    Luhmann, Christian C.; Ahn, Woo-kyoung

    2011-01-01

    In existing models of causal induction, 4 types of covariation information (i.e., presence/absence of an event followed by presence/absence of another event) always exert identical influences on causal strength judgments (e.g., joint presence of events always suggests a generative causal relationship). In contrast, we suggest that, due to…

  13. Computing and information services at the Jet Propulsion Laboratory - A management approach to a diversity of needs

    NASA Technical Reports Server (NTRS)

    Felberg, F. H.

    1984-01-01

    The Jet Propulsion Laboratory, a research and development organization with about 5,000 employees, presents a complicated set of requirements for an institutional system of computing and informational services. The approach taken by JPL in meeting this challenge is one of controlled flexibility. A central communications network is provided, together with selected computing facilities for common use. At the same time, staff members are given considerable discretion in choosing the mini- and microcomputers that they believe will best serve their needs. Consultation services, computer education, and other support functions are also provided.

  14. An Integrated Systems Approach is Needed to Ensure the Sustainability of Antibiotic Effectiveness for Both Humans and Animals.

    PubMed

    So, Anthony D; Shah, Tejen A; Roach, Steven; Ling Chee, Yoke; Nachman, Keeve E

    2015-01-01

    The growing demand for animal products and the widespread use of antibiotics in bringing food animals to market have heightened concerns over cross-species transmission of drug resistance. Both the biology and emerging epidemiology strongly support the need for global coordination in stemming the generation and propagation of resistance, and the patchwork of global and country-level regulations still leaves significant gaps. More importantly, discussing such a framework opens the door to taking modular steps towards solving these challenges - for example, beginning among targeted parties rather than all countries, tying accountability to financial and technical support, or taxing antibiotic use in animals to deter low-value usage of these drugs. An international agreement would allow integrating surveillance data collection, monitoring and enforcement, research into antibiotic alternatives and more sustainable approaches to agriculture, technical assistance and capacity building, and financing under the umbrella of a One Health approach. PMID:26243242

  15. The Importance of Qualitative Research for Causal Explanation in Education

    ERIC Educational Resources Information Center

    Maxwell, Joseph A.

    2012-01-01

    The concept of causation has long been controversial in qualitative research, and many qualitative researchers have rejected causal explanation as incompatible with an interpretivist or constructivist approach. This rejection conflates causation with the positivist "theory" of causation, and ignores an alternative understanding of causation,…

  16. Causal Connections in Educational Panel Data. Final Report.

    ERIC Educational Resources Information Center

    Pelz, Donald C.; Faith, Ray E.

    This final report summarizes past research and suggests new approaches to the problem of estimating long-term individual constants using path analysis. The general objective of the research was to detect and measure the likelihood that one variable, x, measured at time, t, has a causal influence on another variable, y, measured at a subsequent…

  17. Emergence of space-time from topologically homogeneous causal networks

    NASA Astrophysics Data System (ADS)

    Mauro D'Ariano, Giacomo; Tosini, Alessandro

    2013-08-01

    In this paper we study the emergence of Minkowski space-time from a discrete causal network representing a classical information flow. Differently from previous approaches, we require the network to be topologically homogeneous, so that the metric is derived from pure event-counting. Emergence from events has an operational motivation in requiring that every physical quantity-including space-time-be defined through precise measurement procedures. Topological homogeneity is a requirement for having space-time metric emergent from the pure topology of causal connections, whereas physically homogeneity corresponds to the universality of the physical law. We analyze in detail the case of 1+1 dimensions. If we consider the causal connections as an exchange of classical information, we can establish coordinate systems via an Einsteinian protocol, and this leads to a digital version of the Lorentz transformations. In a computational analogy, the foliation construction can be regarded as the synchronization with a global clock of the calls to independent subroutines (corresponding to the causally independent events) in a parallel distributed computation. Thus the Lorentz time-dilation emerges as an increased density of leaves within a single tic-tac of a clock, whereas space-contraction results from the corresponding decrease of density of events per leaf. The operational procedure of building up the coordinate system introduces an in-principle indistinguishability between neighboring events, resulting in a network that is coarse-grained, the thickness of the event being a function of the observer's clock. The illustrated simple classical construction can be extended to space dimension greater than one, with the price of anisotropy of the maximal speed, due to the Weyl-tiling problem. This issue is cured if the causal network is quantum, as e.g. in a quantum cellular automaton, and isotropy is recovered by quantum coherence via superposition of causal paths. We thus argue

  18. Causality vs. Plausibility: Alternative Stances for Inquiry into Human Behavior. Draft.

    ERIC Educational Resources Information Center

    Guba, Egon G.; Lincoln, Yvonna S.

    Arguing that the concept of causality in human experience is archaic, unnecessary, and misleading, particularly in the social/behavioral sciences, a new plausibility approach is proposed for understanding relationships among entities. The epistemological history of causality includes positivist, deductive-nomological, essentialist, activity or…

  19. Reconstructing Constructivism: Causal Models, Bayesian Learning Mechanisms, and the Theory Theory

    ERIC Educational Resources Information Center

    Gopnik, Alison; Wellman, Henry M.

    2012-01-01

    We propose a new version of the "theory theory" grounded in the computational framework of probabilistic causal models and Bayesian learning. Probabilistic models allow a constructivist but rigorous and detailed approach to cognitive development. They also explain the learning of both more specific causal hypotheses and more abstract framework…

  20. Experiments on a wind turbine blade testing an indication for damage using the causal and anti-causal Green's function reconstructed from a diffuse field

    NASA Astrophysics Data System (ADS)

    Tippmann, Jeffery D.; Lanza di Scalea, Francesco

    2014-03-01

    The increasing demand for renewable and clean power generation has resulted in increasing sizes of rotor blades in wind turbine systems. The demanding and variable operational environments have introduced the need for structural health monitoring systems in the blades in order to prevent unexpected downtime events in the operation of the power plant. Many non-destructive evaluation methods used for structural health monitoring purposes need external excitation sources. However, several systems already accepted in the wind turbine industry are passive. Here we present a new approach to health monitoring of a wind turbine blade using only passive sensors and the existing noise created on the blade during operation. This is achieved using a known method to reconstruct the causal and anticausal time-domain Green's function between any two points in an array of passive sensors placed in a diffuse field. Damage is indicated when the similarity between the causal and anticausal signals decrease due to nonlinearities introduced from structural damage. This method was studied experimentally using a CX-100 wind turbine test blade located at the UCSD's Powell Structural Laboratories where a diffuse field was approximated by exciting the skin of the blade with a random signal at several locations.

  1. Does Causal Action Facilitate Causal Perception in Infants Younger than 6 Months of Age?

    ERIC Educational Resources Information Center

    Rakison, David H.; Krogh, Lauren

    2012-01-01

    Previous research has established that infants are unable to perceive causality until 6 1/4 months of age. The current experiments examined whether infants' ability to engage in causal action could facilitate causal perception prior to this age. In Experiment 1, 4 1/2-month-olds were randomly assigned to engage in causal action experience via…

  2. Modeling of causality with metamaterials

    NASA Astrophysics Data System (ADS)

    Smolyaninov, Igor I.

    2013-02-01

    Hyperbolic metamaterials may be used to model a 2 + 1-dimensional Minkowski space-time in which the role of time is played by one of the spatial coordinates. When a metamaterial is built and illuminated with a coherent extraordinary laser beam, the stationary pattern of light propagation inside the metamaterial may be treated as a collection of particle world lines, which represents a complete ‘history’ of this 2 + 1-dimensional space-time. While this model may be used to build interesting space-time analogs, such as metamaterial ‘black holes’ and a metamaterial ‘big bang’, it lacks causality: since light inside the metamaterial may propagate back and forth along the ‘timelike’ spatial coordinate, events in the ‘future’ may affect events in the ‘past’. Here we demonstrate that a more sophisticated metamaterial model may fix this deficiency via breaking the mirror and temporal (PT) symmetries of the original model and producing one-way propagation along the ‘timelike’ spatial coordinate. The resulting 2 + 1-dimensional Minkowski space-time appears to be causal. This scenario may be considered as a metamaterial model of the Wheeler-Feynman absorber theory of causality.

  3. Children's use of interventions to learn causal structure.

    PubMed

    McCormack, Teresa; Bramley, Neil; Frosch, Caren; Patrick, Fiona; Lagnado, David

    2016-01-01

    Children between 5 and 8 years of age freely intervened on a three-variable causal system, with their task being to discover whether it was a common cause structure or one of two causal chains. From 6 or 7 years of age, children were able to use information from their interventions to correctly disambiguate the structure of a causal chain. We used a Bayesian model to examine children's interventions on the system; this showed that with development children became more efficient in producing the interventions needed to disambiguate the causal structure and that the quality of interventions, as measured by their informativeness, improved developmentally. The latter measure was a significant predictor of children's correct inferences about the causal structure. A second experiment showed that levels of performance were not reduced in a task where children did not select and carry out interventions themselves, indicating no advantage for self-directed learning. However, children's performance was not related to intervention quality in these circumstances, suggesting that children learn in a different way when they carry out interventions themselves. PMID:26298433

  4. On the relationship between the causal-inference and meta-analytic paradigms for the validation of surrogate endpoints.

    PubMed

    Alonso, Ariel; Van der Elst, Wim; Molenberghs, Geert; Buyse, Marc; Burzykowski, Tomasz

    2015-03-01

    The increasing cost of drug development has raised the demand for surrogate endpoints when evaluating new drugs in clinical trials. However, over the years, it has become clear that surrogate endpoints need to be statistically evaluated and deemed valid, before they can be used as substitutes of "true" endpoints in clinical studies. Nowadays, two paradigms, based on causal-inference and meta-analysis, dominate the scene. Nonetheless, although the literature emanating from these paradigms is wide, till now the relationship between them has largely been left unexplored. In the present work, we discuss the conceptual framework underlying both approaches and study the relationship between them using theoretical elements and the analysis of a real case study. Furthermore, we show that the meta-analytic approach can be embedded within a causal-inference framework on the one hand and that it can be heuristically justified why surrogate endpoints successfully evaluated using this approach will often be appealing from a causal-inference perspective as well, on the other. A newly developed and user friendly R package Surrogate is provided to carry out the evaluation exercise. PMID:25274284

  5. Statistical Analysis of Single-Trial Granger Causality Spectra

    PubMed Central

    Brovelli, Andrea

    2012-01-01

    Granger causality analysis is becoming central for the analysis of interactions between neural populations and oscillatory networks. However, it is currently unclear whether single-trial estimates of Granger causality spectra can be used reliably to assess directional influence. We addressed this issue by combining single-trial Granger causality spectra with statistical inference based on general linear models. The approach was assessed on synthetic and neurophysiological data. Synthetic bivariate data was generated using two autoregressive processes with unidirectional coupling. We simulated two hypothetical experimental conditions: the first mimicked a constant and unidirectional coupling, whereas the second modelled a linear increase in coupling across trials. The statistical analysis of single-trial Granger causality spectra, based on t-tests and linear regression, successfully recovered the underlying pattern of directional influence. In addition, we characterised the minimum number of trials and coupling strengths required for significant detection of directionality. Finally, we demonstrated the relevance for neurophysiology by analysing two local field potentials (LFPs) simultaneously recorded from the prefrontal and premotor cortices of a macaque monkey performing a conditional visuomotor task. Our results suggest that the combination of single-trial Granger causality spectra and statistical inference provides a valuable tool for the analysis of large-scale cortical networks and brain connectivity. PMID:22649482

  6. Predicting the Cosmological Constant from the Causal Entropic Principle

    SciTech Connect

    Bousso, Raphael; Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad

    2007-05-01

    We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, the principle asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach-weighting by the number of"observers per baryon" -- is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.

  7. Predicting the Cosmological Constant from the CausalEntropic Principle

    SciTech Connect

    Bousso, Raphael; Harnik, Roni; Kribs, Graham D.; Perez, Gilad

    2007-02-20

    We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, it asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach--weighting by the number of ''observers per baryon''--is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.

  8. Stemming the tide of drug-resistant Neisseria gonorrhoeae: the need for an individualized approach to treatment.

    PubMed

    Buono, Sean A; Watson, Tyler D; Borenstein, Lee A; Klausner, Jeffrey D; Pandori, Mark W; Godwin, Hilary A

    2015-02-01

    Drug-resistant Neisseria gonorrhoeae poses a significant public health challenge. In recent years, gonococci resistant to first- and second-line antibiotics have spread worldwide and new strains have developed that are increasingly resistant to third-generation cephalosporins, which are currently our last line of available treatments. Given the timeline required to develop new drugs or an effective vaccine for N. gonorrhoeae, a top priority is to use the drugs that are available as effectively as possible. Currently, clinical management of gonorrhoea is based upon treatment guidelines informed by international gonococcal antimicrobial susceptibility surveillance programmes. This approach, although currently the most practical, is subject to a number of limitations since surveillance data inherently provide population-level information. As a result, basing treatment guidelines on these data can result in the prescription of more aggressive or broader treatment than is needed by individual patients and hence inadvertently contribute to the development and spread of resistance to important drugs. Clearly, methods are needed that provide patient-specific drug susceptibility information in a time frame that would allow clinicians to prescribe individualized treatment regimens for gonorrhoea. Fortunately, in recent years, there have been a number of advances in the development of rapid methods for characterizing both the genotype and the drug resistance phenotype of N. gonorrhoeae strains. Here, we review these advances and propose additional studies that would help facilitate a transition towards an individualized treatment approach for gonorrhoea. PMID:25331059

  9. Exploration of developmental approaches to companion animal antimicrobials: providing for the unmet therapeutic needs of dogs and cats.

    PubMed

    Apley, M; Claxton, R; Davis, C; DeVeau, I; Donecker, J; Lucas, A; Neal, A; Papich, M

    2010-04-01

    The American Academy of Veterinary Pharmacology and Therapeutics (AAVPT) and the United States Pharmacopeia (USP) co-sponsored a workshop to explore approaches for developing companion animal antimicrobials. This workshop was developed in response to the shortage of antimicrobials labeled for dogs and cats, as there is a shortage of approved antimicrobials for the range of infectious diseases commonly treated in small animal practice. The objective of the workshop was to identify alternative approaches to data development to support new indications consistent with the unmet therapeutic needs of dogs and cats. The indications for currently approved antimicrobials do not reflect the broader range of infectious diseases that are commonly diagnosed and treated by the veterinarian. Therefore, the labels for these approved antimicrobials provide limited information to the veterinarian for appropriate therapeutic decision-making beyond the few indications listed. Industry, veterinary practice, and regulatory challenges to the development of new antimicrobial indications were discussed. The workshop resulted in short- and long-term recommendations. Short-term recommendations focus on the use of additional data considerations for product labeling. Long-term recommendations center on legislative or regulatory legal initiatives. The workshop recommendations will need collaboration from industry, academia, and regulatory authorities and a legal shift in the drug approval and availability processes. PMID:20444045

  10. Improving Causality Induction with Category Learning

    PubMed Central

    Wang, Zhihong; Shao, Zhiqing

    2014-01-01

    Causal relations are of fundamental importance for human perception and reasoning. According to the nature of causality, causality has explicit and implicit forms. In the case of explicit form, causal-effect relations exist at either clausal or discourse levels. The implicit causal-effect relations heavily rely on empirical analysis and evidence accumulation. This paper proposes a comprehensive causality extraction system (CL-CIS) integrated with the means of category-learning. CL-CIS considers cause-effect relations in both explicit and implicit forms and especially practices the relation between category and causality in computation. In elaborately designed experiments, CL-CIS is evaluated together with general causality analysis system (GCAS) and general causality analysis system with learning (GCAS-L), and it testified to its own capability and performance in construction of cause-effect relations. This paper confirms the expectation that the precision and coverage of causality induction can be remarkably improved by means of causal and category learning. PMID:24883419

  11. Modeling the Impact of School-Based Universal Depression Screening on Additional Service Capacity Needs: A System Dynamics Approach.

    PubMed

    Lyon, Aaron R; Maras, Melissa A; Pate, Christina M; Igusa, Takeru; Vander Stoep, Ann

    2016-03-01

    Although it is widely known that the occurrence of depression increases over the course of adolescence, symptoms of mood disorders frequently go undetected. While schools are viable settings for conducting universal screening to systematically identify students in need of services for common health conditions, particularly those that adversely affect school performance, few school districts routinely screen their students for depression. Among the most commonly referenced barriers are concerns that the number of students identified may exceed schools' service delivery capacities, but few studies have evaluated this concern systematically. System dynamics (SD) modeling may prove a useful approach for answering questions of this sort. The goal of the current paper is therefore to demonstrate how SD modeling can be applied to inform implementation decisions in communities. In our demonstration, we used SD modeling to estimate the additional service demand generated by universal depression screening in a typical high school. We then simulated the effects of implementing "compensatory approaches" designed to address anticipated increases in service need through (1) the allocation of additional staff time and (2) improvements in the effectiveness of mental health interventions. Results support the ability of screening to facilitate more rapid entry into services and suggest that improving the effectiveness of mental health services for students with depression via the implementation of an evidence-based treatment protocol may have a limited impact on overall recovery rates and service availability. In our example, the SD approach proved useful in informing systems' decision-making about the adoption of a new school mental health service. PMID:25601192

  12. Causality in Psychiatry: A Hybrid Symptom Network Construct Model.

    PubMed

    Young, Gerald

    2015-01-01

    Causality or etiology in psychiatry is marked by standard biomedical, reductionistic models (symptoms reflect the construct involved) that inform approaches to nosology, or classification, such as in the DSM-5 [Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition; (1)]. However, network approaches to symptom interaction [i.e., symptoms are formative of the construct; e.g., (2), for posttraumatic stress disorder (PTSD)] are being developed that speak to bottom-up processes in mental disorder, in contrast to the typical top-down psychological construct approach. The present article presents a hybrid top-down, bottom-up model of the relationship between symptoms and mental disorder, viewing symptom expression and their causal complex as a reciprocally dynamic system with multiple levels, from lower-order symptoms in interaction to higher-order constructs affecting them. The hybrid model hinges on good understanding of systems theory in which it is embedded, so that the article reviews in depth non-linear dynamical systems theory (NLDST). The article applies the concept of emergent circular causality (3) to symptom development, as well. Conclusions consider that symptoms vary over several dimensions, including: subjectivity; objectivity; conscious motivation effort; and unconscious influences, and the degree to which individual (e.g., meaning) and universal (e.g., causal) processes are involved. The opposition between science and skepticism is a complex one that the article addresses in final comments. PMID:26635639

  13. Causality in Psychiatry: A Hybrid Symptom Network Construct Model

    PubMed Central

    Young, Gerald

    2015-01-01

    Causality or etiology in psychiatry is marked by standard biomedical, reductionistic models (symptoms reflect the construct involved) that inform approaches to nosology, or classification, such as in the DSM-5 [Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition; (1)]. However, network approaches to symptom interaction [i.e., symptoms are formative of the construct; e.g., (2), for posttraumatic stress disorder (PTSD)] are being developed that speak to bottom-up processes in mental disorder, in contrast to the typical top-down psychological construct approach. The present article presents a hybrid top-down, bottom-up model of the relationship between symptoms and mental disorder, viewing symptom expression and their causal complex as a reciprocally dynamic system with multiple levels, from lower-order symptoms in interaction to higher-order constructs affecting them. The hybrid model hinges on good understanding of systems theory in which it is embedded, so that the article reviews in depth non-linear dynamical systems theory (NLDST). The article applies the concept of emergent circular causality (3) to symptom development, as well. Conclusions consider that symptoms vary over several dimensions, including: subjectivity; objectivity; conscious motivation effort; and unconscious influences, and the degree to which individual (e.g., meaning) and universal (e.g., causal) processes are involved. The opposition between science and skepticism is a complex one that the article addresses in final comments. PMID:26635639

  14. Identifying tree crown delineation shapes and need for remediation on high resolution imagery using an evidence based approach

    NASA Astrophysics Data System (ADS)

    Leckie, Donald G.; Walsworth, Nicholas; Gougeon, François A.

    2016-04-01

    In order to fully realize the benefits of automated individual tree mapping for tree species, health, forest inventory attribution and forest management decision making, the tree delineations should be as good as possible. The concept of identifying poorly delineated tree crowns and suggesting likely types of remediation was investigated. Delineations (isolations or isols) were classified into shape types reflecting whether they were realistic tree shapes and the likely kind of remediation needed. Shape type was classified by an evidence based rules approach using primitives based on isol size, shape indices, morphology, the presence of local maxima, and matches with template models representing trees of different sizes. A test set containing 50,000 isols based on an automated tree delineation of 40 cm multispectral airborne imagery of a diverse temperate-boreal forest site was used. Isolations representing single trees or several trees were the focus, as opposed to cases where a tree is split into several isols. For eight shape classes from regular through to convolute, shape classification accuracy was in the order of 62%; simplifying to six classes accuracy was 83%. Shape type did give an indication of the type of remediation and there were 6% false alarms (i.e., isols classed as needing remediation but did not). Alternately, there were 5% omissions (i.e., isols of regular shape and not earmarked for remediation that did need remediation). The usefulness of the concept of identifying poor delineations in need of remediation was demonstrated and one suite of methods developed and shown to be effective.

  15. Inferring causal molecular networks: empirical assessment through a community-based effort.

    PubMed

    Hill, Steven M; Heiser, Laura M; Cokelaer, Thomas; Unger, Michael; Nesser, Nicole K; Carlin, Daniel E; Zhang, Yang; Sokolov, Artem; Paull, Evan O; Wong, Chris K; Graim, Kiley; Bivol, Adrian; Wang, Haizhou; Zhu, Fan; Afsari, Bahman; Danilova, Ludmila V; Favorov, Alexander V; Lee, Wai Shing; Taylor, Dane; Hu, Chenyue W; Long, Byron L; Noren, David P; Bisberg, Alexander J; Mills, Gordon B; Gray, Joe W; Kellen, Michael; Norman, Thea; Friend, Stephen; Qutub, Amina A; Fertig, Elana J; Guan, Yuanfang; Song, Mingzhou; Stuart, Joshua M; Spellman, Paul T; Koeppl, Heinz; Stolovitzky, Gustavo; Saez-Rodriguez, Julio; Mukherjee, Sach

    2016-04-01

    It remains unclear whether causal, rather than merely correlational, relationships in molecular networks can be inferred in complex biological settings. Here we describe the HPN-DREAM network inference challenge, which focused on learning causal influences in signaling networks. We used phosphoprotein data from cancer cell lines as well as in silico data from a nonlinear dynamical model. Using the phosphoprotein data, we scored more than 2,000 networks submitted by challenge participants. The networks spanned 32 biological contexts and were scored in terms of causal validity with respect to unseen interventional data. A number of approaches were effective, and incorporating known biology was generally advantageous. Additional sub-challenges considered time-course prediction and visualization. Our results suggest that learning causal relationships may be feasible in complex settings such as disease states. Furthermore, our scoring approach provides a practical way to empirically assess inferred molecular networks in a causal sense. PMID:26901648

  16. An Empirical Approach to Ocean Color Data: Reducing Bias and the Need for Post-Launch Radiometric Re-Calibration

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.; Casey, Nancy W.; O'Reilly, John E.; Esaias, Wayne E.

    2009-01-01

    A new empirical approach is developed for ocean color remote sensing. Called the Empirical Satellite Radiance-In situ Data (ESRID) algorithm, the approach uses relationships between satellite water-leaving radiances and in situ data after full processing, i.e., at Level-3, to improve estimates of surface variables while relaxing requirements on post-launch radiometric re-calibration. The approach is evaluated using SeaWiFS chlorophyll, which is the longest time series of the most widely used ocean color geophysical product. The results suggest that ESRID 1) drastically reduces the bias of ocean chlorophyll, most impressively in coastal regions, 2) modestly improves the uncertainty, and 3) reduces the sensitivity of global annual median chlorophyll to changes in radiometric re-calibration. Simulated calibration errors of 1% or less produce small changes in global median chlorophyll (less than 2.7%). In contrast, the standard NASA algorithm set is highly sensitive to radiometric calibration: similar 1% calibration errors produce changes in global median chlorophyll up to nearly 25%. We show that 0.1% radiometric calibration error (about 1% in water-leaving radiance) is needed to prevent radiometric calibration errors from changing global annual median chlorophyll more than the maximum interannual variability observed in the SeaWiFS 9-year record (+/- 3%), using the standard method. This is much more stringent than the goal for SeaWiFS of 5% uncertainty for water leaving radiance. The results suggest ocean color programs might consider less emphasis of expensive efforts to improve post-launch radiometric re-calibration in favor of increased efforts to characterize in situ observations of ocean surface geophysical products. Although the results here are focused on chlorophyll, in principle the approach described by ESRID can be applied to any surface variable potentially observable by visible remote sensing.

  17. Equity Theory Ratios as Causal Schemas

    PubMed Central

    Arvanitis, Alexios; Hantzi, Alexandra

    2016-01-01

    Equity theory approaches justice evaluations based on ratios of exchange inputs to exchange outcomes. Situations are evaluated as just if ratios are equal and unjust if unequal. We suggest that equity ratios serve a more fundamental cognitive function than the evaluation of justice. More particularly, we propose that they serve as causal schemas for exchange outcomes, that is, they assist in determining whether certain outcomes are caused by inputs of other people in the context of an exchange process. Equality or inequality of ratios in this sense points to an exchange process. Indeed, Study 1 shows that different exchange situations, such as disproportional or balanced proportional situations, create perceptions of give-and-take on the basis of equity ratios. Study 2 shows that perceptions of justice are based more on communicatively accepted rules of interaction than equity-based evaluations, thereby offering a distinction between an attribution and an evaluation cognitive process for exchange outcomes. PMID:27594846

  18. Equity Theory Ratios as Causal Schemas.

    PubMed

    Arvanitis, Alexios; Hantzi, Alexandra

    2016-01-01

    Equity theory approaches justice evaluations based on ratios of exchange inputs to exchange outcomes. Situations are evaluated as just if ratios are equal and unjust if unequal. We suggest that equity ratios serve a more fundamental cognitive function than the evaluation of justice. More particularly, we propose that they serve as causal schemas for exchange outcomes, that is, they assist in determining whether certain outcomes are caused by inputs of other people in the context of an exchange process. Equality or inequality of ratios in this sense points to an exchange process. Indeed, Study 1 shows that different exchange situations, such as disproportional or balanced proportional situations, create perceptions of give-and-take on the basis of equity ratios. Study 2 shows that perceptions of justice are based more on communicatively accepted rules of interaction than equity-based evaluations, thereby offering a distinction between an attribution and an evaluation cognitive process for exchange outcomes. PMID:27594846

  19. Lightweight causal and atomic group multicast

    NASA Technical Reports Server (NTRS)

    Birman, Kenneth P.; Schiper, Andre; Stephenson, Pat

    1991-01-01

    The ISIS toolkit is a distributed programming environment based on support for virtually synchronous process groups and group communication. A suite of protocols is presented to support this model. The approach revolves around a multicast primitive, called CBCAST, which implements a fault-tolerant, causally ordered message delivery. This primitive can be used directly or extended into a totally ordered multicast primitive, called ABCAST. It normally delivers messages immediately upon reception, and imposes a space overhead proportional to the size of the groups to which the sender belongs, usually a small number. It is concluded that process groups and group communication can achieve performance and scaling comparable to that of a raw message transport layer. This finding contradicts the widespread concern that this style of distributed computing may be unacceptably costly.

  20. Monitoring is not enough: on the need for a model-based approach to migratory bird management

    USGS Publications Warehouse

    Nichols, J.D.

    2000-01-01

    Informed management requires information about system state and about effects of potential management actions on system state. Population monitoring can provide the needed information about system state, as well as information that can be used to investigate effects of management actions. Three methods for investigating effects of management on bird populations are (1) retrospective analysis, (2) formal experimentation and constrained-design studies, and (3) adaptive management. Retrospective analyses provide weak inferences, regardless of the quality of the monitoring data. The active use of monitoring data in experimental or constrained-design studies or in adaptive management is recommended. Under both approaches, learning occurs via the comparison of estimates from the monitoring program with predictions from competing management models.

  1. The discourse of causal explanations in school science

    NASA Astrophysics Data System (ADS)

    Slater, Tammy Jayne Anne

    Researchers and educators working from a systemic functional linguistic perspective have provided a body of work on science discourse which offers an excellent starting point for examining the linguistic aspects of the development of causal discourse in school science, discourse which Derewianka (1995) claimed is critical to success in secondary school. No work has yet described the development of causal language by identifying the linguistic features present in oral discourse or by comparing the causal discourse of native and non-native (ESL) speakers of English. The current research responds to this gap by examining the oral discourse collected from ESL and non-ESL students at the primary and high school grades. Specifically, it asks the following questions: (1) How do the teachers and students in these four contexts develop causal explanations and their relevant taxonomies through classroom interactions? (2) What are the causal discourse features being used by the students in these four contexts to construct oral causal explanations? The findings of the social practice analysis showed that the teachers in the four contexts differed in their approaches to teaching, with the primary school mainstream teacher focusing largely on the hands-on practice , the primary school ESL teacher moving from practice to theory, the high school mainstream teacher moving from theory to practice, and the high school ESL teacher relying primarily on theory. The findings from the quantitative, small corpus approach suggest that the developmental path of cause which has been identified in the writing of experts shows up not only in written texts but also in the oral texts which learners construct. Moreover, this move appears when the discourse of high school ESL and non-ESL students is compared, suggesting a developmental progression in the acquisition of these features by these students. The findings also reveal that the knowledge constructed, as shown by the concept maps created

  2. Planning for climate change: The need for mechanistic systems-based approaches to study climate change impacts on diarrheal diseases.

    PubMed

    Mellor, Jonathan E; Levy, Karen; Zimmerman, Julie; Elliott, Mark; Bartram, Jamie; Carlton, Elizabeth; Clasen, Thomas; Dillingham, Rebecca; Eisenberg, Joseph; Guerrant, Richard; Lantagne, Daniele; Mihelcic, James; Nelson, Kara

    2016-04-01

    Increased precipitation and temperature variability as well as extreme events related to climate change are predicted to affect the availability and quality of water globally. Already heavily burdened with diarrheal diseases due to poor access to water, sanitation and hygiene facilities, communities throughout the developing world lack the adaptive capacity to sufficiently respond to the additional adversity caused by climate change. Studies suggest that diarrhea rates are positively correlated with increased temperature, and show a complex relationship with precipitation. Although climate change will likely increase rates of diarrheal diseases on average, there is a poor mechanistic understanding of the underlying disease transmission processes and substantial uncertainty surrounding current estimates. This makes it difficult to recommend appropriate adaptation strategies. We review the relevant climate-related mechanisms behind transmission of diarrheal disease pathogens and argue that systems-based mechanistic approaches incorporating human, engineered and environmental components are urgently needed. We then review successful systems-based approaches used in other environmental health fields and detail one modeling framework to predict climate change impacts on diarrheal diseases and design adaptation strategies. PMID:26799810

  3. Planning for climate change: the need for mechanistic systems-based approaches to study climate change impacts on diarrheal diseases

    PubMed Central

    Levy, Karen; Zimmerman, Julie; Elliott, Mark; Bartram, Jamie; Carlton, Elizabeth; Clasen, Thomas; Dillingham, Rebecca; Eisenberg, Joseph; Guerrant, Richard; Lantagne, Daniele; Mihelcic, James; Nelson, Kara

    2016-01-01

    Increased precipitation and temperature variability as well as extreme events related to climate change are predicted to affect the availability and quality of water globally. Already heavily burdened with diarrheal diseases due to poor access to water, sanitation and hygiene facilities, communities throughout the developing world lack the adaptive capacity to sufficiently respond to the additional adversity caused by climate change. Studies suggest that diarrhea rates are positively correlated with increased temperature, and show a complex relationship with precipitation. Although climate change will likely increase rates of diarrheal diseases on average, there is a poor mechanistic understanding of the underlying disease transmission processes and substantial uncertainty surrounding current estimates. This makes it difficult to recommend appropriate adaptation strategies. We review the relevant climate-related mechanisms behind transmission of diarrheal disease pathogens and argue that systems-based mechanistic approaches incorporating human, engineered and environmental components are urgently needed. We then review successful systems-based approaches used in other environmental health fields and detail one modeling framework to predict climate change impacts on diarrheal diseases and design adaptation strategies. PMID:26799810

  4. Causal diagrams in systems epidemiology

    PubMed Central

    2012-01-01

    Methods of diagrammatic modelling have been greatly developed in the past two decades. Outside the context of infectious diseases, systematic use of diagrams in epidemiology has been mainly confined to the analysis of a single link: that between a disease outcome and its proximal determinant(s). Transmitted causes ("causes of causes") tend not to be systematically analysed. The infectious disease epidemiology modelling tradition models the human population in its environment, typically with the exposure-health relationship and the determinants of exposure being considered at individual and group/ecological levels, respectively. Some properties of the resulting systems are quite general, and are seen in unrelated contexts such as biochemical pathways. Confining analysis to a single link misses the opportunity to discover such properties. The structure of a causal diagram is derived from knowledge about how the world works, as well as from statistical evidence. A single diagram can be used to characterise a whole research area, not just a single analysis - although this depends on the degree of consistency of the causal relationships between different populations - and can therefore be used to integrate multiple datasets. Additional advantages of system-wide models include: the use of instrumental variables - now emerging as an important technique in epidemiology in the context of mendelian randomisation, but under-used in the exploitation of "natural experiments"; the explicit use of change models, which have advantages with respect to inferring causation; and in the detection and elucidation of feedback. PMID:22429606

  5. Comparison theorems for causal diamonds

    NASA Astrophysics Data System (ADS)

    Berthiere, Clément; Gibbons, Gary; Solodukhin, Sergey N.

    2015-09-01

    We formulate certain inequalities for the geometric quantities characterizing causal diamonds in curved and Minkowski spacetimes. These inequalities involve the redshift factor which, as we show explicitly in the spherically symmetric case, is monotonic in the radial direction, and it takes its maximal value at the center. As a by-product of our discussion we rederive Bishop's inequality without assuming the positivity of the spatial Ricci tensor. We then generalize our considerations to arbitrary, static and not necessarily spherically symmetric, asymptotically flat spacetimes. In the case of spacetimes with a horizon our generalization involves the so-called domain of dependence. The respective volume, expressed in terms of the duration measured by a distant observer compared with the volume of the domain in Minkowski spacetime, exhibits behaviors which differ if d =4 or d >4 . This peculiarity of four dimensions is due to the logarithmic subleading term in the asymptotic expansion of the metric near infinity. In terms of the invariant duration measured by a comoving observer associated with the diamond we establish an inequality which is universal for all d . We suggest some possible applications of our results including comparison theorems for entanglement entropy, causal set theory, and fundamental limits on computation.

  6. G-computation demonstration in causal mediation analysis.

    PubMed

    Wang, Aolin; Arah, Onyebuchi A

    2015-10-01

    Recent work has considerably advanced the definition, identification and estimation of controlled direct, and natural direct and indirect effects in causal mediation analysis. Despite the various estimation methods and statistical routines being developed, a unified approach for effect estimation under different effect decomposition scenarios is still needed for epidemiologic research. G-computation offers such unification and has been used for total effect and joint controlled direct effect estimation settings, involving different types of exposure and outcome variables. In this study, we demonstrate the utility of parametric g-computation in estimating various components of the total effect, including (1) natural direct and indirect effects, (2) standard and stochastic controlled direct effects, and (3) reference and mediated interaction effects, using Monte Carlo simulations in standard statistical software. For each study subject, we estimated their nested potential outcomes corresponding to the (mediated) effects of an intervention on the exposure wherein the mediator was allowed to attain the value it would have under a possible counterfactual exposure intervention, under a pre-specified distribution of the mediator independent of any causes, or under a fixed controlled value. A final regression of the potential outcome on the exposure intervention variable was used to compute point estimates and bootstrap was used to obtain confidence intervals. Through contrasting different potential outcomes, this analytical framework provides an intuitive way of estimating effects under the recently introduced 3- and 4-way effect decomposition. This framework can be extended to complex multivariable and longitudinal mediation settings. PMID:26537707

  7. Obesity and asthma: co-morbidity or causal relationship?

    PubMed

    van Huisstede, A; Braunstahl, G J

    2010-09-01

    There is substantial evidence that obesity and asthma are related. "Obese asthma" may be a unique phenotype of asthma, characterized by decreased lung volumes, greater symptoms for a given degree of lung function impairment, destabilization or lack of asthma control, lack of eosinophilic inflammation and a different response to controller medication. Whether this relationship between obesity and asthma is causal or represents co-morbidity due to other factors is unclear. In previous reviews concerning the relationship between obesity and asthma, five hypotheses were put forth. One of these hypotheses is that a low grade systemic inflammation caused by adipokines from the fat tissue causes or enhances bronchial inflammation. In animal models, there is an increasing amount of evidence for the role of adipokines derived from fat tissue in the relationship between obesity and asthma. The data are conflicting in humans. Since obesity is a component of the metabolic syndrome and the metabolic syndrome is also a form of systemic inflammation, it is to be expected that there is a relationship between metabolic syndrome and asthma. The few data that are available show that there is no relationship between metabolic syndrome and asthma, but there is one between the metabolic syndrome and asthma-like symptoms. Further research is needed to confirm the relationship between obesity and asthma in humans, where a rigorous approach in the diagnosis of asthma is essential. PMID:21214041

  8. [Causality in occupational health: the Ardystil case].

    PubMed

    García García, A M; Benavides, F G

    1995-01-01

    Establishing causal relationships has been and is today a matter of debate in epidemiology. The observational nature of epidemiological research rends difficult the proving of these relationships. Related to this, different models and causal criteria have been proposed in order to explain health and disease determinants, from pure determinism in Koch postulates, accepting unicausal explanation for diseases, to more realistic multicausal models. In occupational health it is necessary to formulate causal models and criteria to assess causality, and frequently causal assessment in this field has important social, economic and juridical relevance. This paper deal with evaluation of causal relationships in epidemiology and this evaluation is illustrated with a recent example of an occupational health problem in our milieu: the Ardystil case. PMID:8666516

  9. Nonparametric causal inference for bivariate time series

    NASA Astrophysics Data System (ADS)

    McCracken, James M.; Weigel, Robert S.

    2016-02-01

    We introduce new quantities for exploratory causal inference between bivariate time series. The quantities, called penchants and leanings, are computationally straightforward to apply, follow directly from assumptions of probabilistic causality, do not depend on any assumed models for the time series generating process, and do not rely on any embedding procedures; these features may provide a clearer interpretation of the results than those from existing time series causality tools. The penchant and leaning are computed based on a structured method for computing probabilities.

  10. Causal inference in economics and marketing.

    PubMed

    Varian, Hal R

    2016-07-01

    This is an elementary introduction to causal inference in economics written for readers familiar with machine learning methods. The critical step in any causal analysis is estimating the counterfactual-a prediction of what would have happened in the absence of the treatment. The powerful techniques used in machine learning may be useful for developing better estimates of the counterfactual, potentially improving causal inference. PMID:27382144

  11. Causal inference in economics and marketing

    PubMed Central

    Varian, Hal R.

    2016-01-01

    This is an elementary introduction to causal inference in economics written for readers familiar with machine learning methods. The critical step in any causal analysis is estimating the counterfactual—a prediction of what would have happened in the absence of the treatment. The powerful techniques used in machine learning may be useful for developing better estimates of the counterfactual, potentially improving causal inference. PMID:27382144

  12. Illusions of causality: how they bias our everyday thinking and how they could be reduced.

    PubMed

    Matute, Helena; Blanco, Fernando; Yarritu, Ion; Díaz-Lago, Marcos; Vadillo, Miguel A; Barberia, Itxaso

    2015-01-01

    Illusions of causality occur when people develop the belief that there is a causal connection between two events that are actually unrelated. Such illusions have been proposed to underlie pseudoscience and superstitious thinking, sometimes leading to disastrous consequences in relation to critical life areas, such as health, finances, and wellbeing. Like optical illusions, they can occur for anyone under well-known conditions. Scientific thinking is the best possible safeguard against them, but it does not come intuitively and needs to be taught. Teaching how to think scientifically should benefit from better understanding of the illusion of causality. In this article, we review experiments that our group has conducted on the illusion of causality during the last 20 years. We discuss how research on the illusion of causality can contribute to the teaching of scientific thinking and how scientific thinking can reduce illusion. PMID:26191014

  13. Illusions of causality: how they bias our everyday thinking and how they could be reduced

    PubMed Central

    Matute, Helena; Blanco, Fernando; Yarritu, Ion; Díaz-Lago, Marcos; Vadillo, Miguel A.; Barberia, Itxaso

    2015-01-01

    Illusions of causality occur when people develop the belief that there is a causal connection between two events that are actually unrelated. Such illusions have been proposed to underlie pseudoscience and superstitious thinking, sometimes leading to disastrous consequences in relation to critical life areas, such as health, finances, and wellbeing. Like optical illusions, they can occur for anyone under well-known conditions. Scientific thinking is the best possible safeguard against them, but it does not come intuitively and needs to be taught. Teaching how to think scientifically should benefit from better understanding of the illusion of causality. In this article, we review experiments that our group has conducted on the illusion of causality during the last 20 years. We discuss how research on the illusion of causality can contribute to the teaching of scientific thinking and how scientific thinking can reduce illusion. PMID:26191014

  14. Reverse causal reasoning: applying qualitative causal knowledge to the interpretation of high-throughput data

    PubMed Central

    2013-01-01

    Background Gene expression profiling and other genome-scale measurement technologies provide comprehensive information about molecular changes resulting from a chemical or genetic perturbation, or disease state. A critical challenge is the development of methods to interpret these large-scale data sets to identify specific biological mechanisms that can provide experimentally verifiable hypotheses and lead to the understanding of disease and drug action. Results We present a detailed description of Reverse Causal Reasoning (RCR), a reverse engineering methodology to infer mechanistic hypotheses from molecular profiling data. This methodology requires prior knowledge in the form of small networks that causally link a key upstream controller node representing a biological mechanism to downstream measurable quantities. These small directed networks are generated from a knowledge base of literature-curated qualitative biological cause-and-effect relationships expressed as a network. The small mechanism networks are evaluated as hypotheses to explain observed differential measurements. We provide a simple implementation of this methodology, Whistle, specifically geared towards the analysis of gene expression data and using prior knowledge expressed in Biological Expression Language (BEL). We present the Whistle analyses for three transcriptomic data sets using a publically available knowledge base. The mechanisms inferred by Whistle are consistent with the expected biology for each data set. Conclusions Reverse Causal Reasoning yields mechanistic insights to the interpretation of gene expression profiling data that are distinct from and complementary to the results of analyses using ontology or pathway gene sets. This reverse engineering algorithm provides an evidence-driven approach to the development of models of disease, drug action, and drug toxicity. PMID:24266983

  15. A Rational Approach to Estimating the Surgical Demand Elasticity Needed to Guide Manpower Reallocation during Contagious Outbreaks

    PubMed Central

    Tsao, Hsiao-Mei; Sun, Ying-Chou; Liou, Der-Ming

    2015-01-01

    Background Emerging infectious diseases continue to pose serious threats to global public health. So far, however, few published study has addressed the need for manpower reallocation needed in hospitals when such a serious contagious outbreak occurs. Aim To quantify the demand elasticity of the major surgery types in order to guide future manpower reallocation during contagious outbreaks. Materials and Methods Based on a nationwide research database in Taiwan, we extracted the monthly volumes of major surgery types for the period 1998–2003, which covered the SARS period, in order to carry out a time series analysis. The demand elasticity of each surgery type was then estimated by autoregressive integrated moving average (ARIMA) analysis. Results During the study period, the surgical volumes of most selected surgery types either increased or remained steady. We categorized these surgery types into low-, moderate- and high-elastic groups according to their demand elasticity. Appendectomy, ‘open reduction of fracture with internal fixation’ and ‘free skin graft’ were in the low demand elasticity group. Transurethral prostatectomy and extracorporeal shockwave lithotripsy (ESWL) were in the high demand elasticity group. The manpower of the departments carrying out the surgeries with low demand elasticity should be maintained during outbreaks. In contrast, departments in charge of surgeries mainly with high demand elasticity, like urology departments, may be in a position to have part of their staff reallocated. Conclusions Taking advantage of the demand variation during the SARS period in 2003, we adopted the concept of demand elasticity and used a time series approach to figure out an effective index of demand elasticity for various types of surgery that could be used as a rational reference to carry out manpower reallocation during contagious outbreak situations. PMID:25837596

  16. Causality from the Cosmological Perspective in Vedanta and Western Physics.

    NASA Astrophysics Data System (ADS)

    Hawley, Danny Lee

    The relation between Western physics and Indian Vedanta philosophy is investigated through the topic of causality, taken in the sense of explanatory theories of the origin of the universe and the relations among its physical, mental, and spiritual aspects. Both physics and Vedanta have a common goal of explanation by means of a unitary principle. While physics has long been separated from metaphysics, its discoveries indicate that consciousness must be included in a complete explanation. Consciousness is taken as the fundamental basis and source of all phenomena in Vedanta. This work traces the developments of causal explanation in Western physics and Indian philosophy, and considers how these views may relate to each other and how they may together suggest a comprehensive view of reality. Approaches typically applied by historians of religion to the study of creation myths, especially the psychological approach which considers myths from the perspective or cyclical stages of conscious development, are applied to the causal theories of the two cultures. The question of how causal explanations attempt to bridge the gap between cause and effect, unity and multiplicity, absolute and relative, conscious and unconscious, etc., is addressed. Though the investigation begins from the earliest causal explanations, viz., creation myths, emphasis is placed upon Samkara's commentaries of Advaita Vedanta, examined in the original Sanskrit, and upon the convergence of modern field theory, astrophysics, and cosmology, seen from the perspective of a previous doctorate in physics. Consideration is given to the comparison between physics and Vedanta as to goals, methods, and domains, to the question of the incompleteness of physics and the extent to which it nevertheless points beyond itself, to the possibility of a synthetic view and how it might be effected, and to analogies and metaphors through which physics and Vedanta may illuminate each other. An intuitive picture is

  17. Tutorial in Biostatistics: Instrumental Variable Methods for Causal Inference*

    PubMed Central

    Baiocchi, Michael; Cheng, Jing; Small, Dylan S.

    2014-01-01

    A goal of many health studies is to determine the causal effect of a treatment or intervention on health outcomes. Often, it is not ethically or practically possible to conduct a perfectly randomized experiment and instead an observational study must be used. A major challenge to the validity of observational studies is the possibility of unmeasured confounding (i.e., unmeasured ways in which the treatment and control groups differ before treatment administration which also affect the outcome). Instrumental variables analysis is a method for controlling for unmeasured confounding. This type of analysis requires the measurement of a valid instrumental variable, which is a variable that (i) is independent of the unmeasured confounding; (ii) affects the treatment; and (iii) affects the outcome only indirectly through its effect on the treatment. This tutorial discusses the types of causal effects that can be estimated by instrumental variables analysis; the assumptions needed for instrumental variables analysis to provide valid estimates of causal effects and sensitivity analysis for those assumptions; methods of estimation of causal effects using instrumental variables; and sources of instrumental variables in health studies. PMID:24599889

  18. How can we cope with the complexity of the environment? A "Learning by modelling" approach using qualitative reasoning for developing causal models and simulations with focus on Sustainable River Catchment Management

    NASA Astrophysics Data System (ADS)

    Poppe, Michaela; Zitek, Andreas; Salles, Paulo; Bredeweg, Bert; Muhar, Susanne

    2010-05-01

    The education system needs strategies to attract future scientists and practitioners. There is an alarming decline in the number of students choosing science subjects. Reasons for this include the perceived complexity and the lack of effective cognitive tools that enable learners to acquire the expertise in a way that fits its qualitative nature. The DynaLearn project utilises a "Learning by modelling" approach to deliver an individualised and engaging cognitive tool for acquiring conceptual knowledge. The modelling approach is based on qualitative reasoning, a research area within artificial intelligence, and allows for capturing and simulating qualitative systems knowledge. Educational activities within the DynaLearn software address topics at different levels of complexity, depending on the educational goals and settings. DynaLearn uses virtual characters in the learning environment as agents for engaging and motivating the students during their modelling exercise. The DynaLearn software represents an interactive learning environment in which learners are in control of their learning activities. The software is able to coach them individually based on their current progress, their knowledge needs and learning goals. Within the project 70 expert models on different environmental issues covering seven core topics (Earth Systems and Resources, The Living World, Human population, Land and Water Use, Energy Resources and Consumption, Pollution, and Global Changes) will be delivered. In the context of the core topic "Land and Water Use" the Institute of Hydrobiology and Aquatic Ecosystem Management has developed a model on Sustainable River Catchment Management. River systems with their catchments have been tremendously altered due to human pressures with serious consequences for the ecological integrity of riverine landscapes. The operation of hydropower plants, the implementation of flood protection measures, the regulation of flow and sediment regime and intensive

  19. Causal compensated perturbations in cosmology

    NASA Technical Reports Server (NTRS)

    Veeraraghavan, Shoba; Stebbins, Albert

    1990-01-01

    A theoretical framework is developed to calculate linear perturbations in the gravitational and matter fields which arise causally in response to the presence of stiff matter sources in a FRW cosmology. It is shown that, in order to satisfy energy and momentum conservation, the gravitational fields of the source must be compensated by perturbations in the matter and gravitational fields, and the role of such compensation in containing the initial inhomogeneities in their subsequent evolution is discussed. A complete formal solution is derived in terms of Green functions for the perturbations produced by an arbitrary source in a flat universe containing cold dark matter. Approximate Green function solutions are derived for the late-time density perturbations and late-time gravitational waves in a universe containing a radiation fluid. A cosmological energy-momentum pseudotensor is defined to clarify the nature of energy and momentum conservation in the expanding universe.

  20. Causal Systems Categories: Differences in Novice and Expert Categorization of Causal Phenomena

    ERIC Educational Resources Information Center

    Rottman, Benjamin M.; Gentner, Dedre; Goldwater, Micah B.

    2012-01-01

    We investigated the understanding of causal systems categories--categories defined by common causal structure rather than by common domain content--among college students. We asked students who were either novices or experts in the physical sciences to sort descriptions of real-world phenomena that varied in their causal structure (e.g., negative…

  1. Knowing Who Dunnit: Infants Identify the Causal Agent in an Unseen Causal Interaction

    ERIC Educational Resources Information Center

    Saxe, Rebecca; Tzelnic, Tania; Carey, Susan

    2007-01-01

    Preverbal infants can represent the causal structure of events, including distinguishing the agentive and receptive roles and categorizing entities according to stable causal dispositions. This study investigated how infants combine these 2 kinds of causal inference. In Experiments 1 and 2, 9.5-month-olds used the position of a human hand or a…

  2. The Power of Causal Beliefs and Conflicting Evidence on Causal Judgments and Decision Making

    ERIC Educational Resources Information Center

    Garcia-Retamero, Rocio; Muller, Stephanie M.; Catena, Andres; Maldonado, Antonio

    2009-01-01

    In two experiments, we investigated the relative impact of causal beliefs and empirical evidence on both decision making and causal judgments, and whether this relative impact could be altered by previous experience. 2. Selected groups of participants in both experiments received pre-training with either causal or neutral cues, or no pre-training…

  3. The role of duplications in the evolution of genomes highlights the need for evolutionary-based approaches in comparative genomics

    PubMed Central

    2011-01-01

    Understanding the evolutionary plasticity of the genome requires a global, comparative approach in which genetic events are considered both in a phylogenetic framework and with regard to population genetics and environmental variables. In the mechanisms that generate adaptive and non-adaptive changes in genomes, segmental duplications (duplication of individual genes or genomic regions) and polyploidization (whole genome duplications) are well-known driving forces. The probability of fixation and maintenance of duplicates depends on many variables, including population sizes and selection regimes experienced by the corresponding genes: a combination of stochastic and adaptive mechanisms has shaped all genomes. A survey of experimental work shows that the distinction made between fixation and maintenance of duplicates still needs to be conceptualized and mathematically modeled. Here we review the mechanisms that increase or decrease the probability of fixation or maintenance of duplicated genes, and examine the outcome of these events on the adaptation of the organisms. Reviewers This article was reviewed by Dr. Etienne Joly, Dr. Lutz Walter and Dr. W. Ford Doolittle. PMID:21333002

  4. An integrated approach is needed for ecosystem based fisheries management: insights from ecosystem-level management strategy evaluation.

    PubMed

    Fulton, Elizabeth A; Smith, Anthony D M; Smith, David C; Johnson, Penelope

    2014-01-01

    An ecosystem approach is widely seen as a desirable goal for fisheries management but there is little consensus on what strategies or measures are needed to achieve it. Management strategy evaluation (MSE) is a tool that has been widely used to develop and test single species fisheries management strategies and is now being extended to support ecosystem based fisheries management (EBFM). We describe the application of MSE to investigate alternative strategies for achieving EBFM goals for a complex multispecies fishery in southeastern Australia. The study was undertaken as part of a stakeholder driven process to review and improve the ecological, economic and social performance of the fishery. An integrated management strategy, involving combinations of measures including quotas, gear controls and spatial management, performed best against a wide range of objectives and this strategy was subsequently adopted in the fishery, leading to marked improvements in performance. Although particular to one fishery, the conclusion that an integrated package of measures outperforms single focus measures we argue is likely to apply widely in fisheries that aim to achieve EBFM goals. PMID:24454722

  5. Training and Certification for Domestic Violence Service Providers: The Need for a National Standard Curriculum and Training Approach

    PubMed Central

    Stover, Carla Smith; Lent, Kimberly

    2014-01-01

    Domestic violence (DV) continues to constitute an enormous public health problem in the United States. Knowledge and understanding of the complexities involved in DV has grown significantly in recent years revealing a need for providers who have broad training in a variety of legal, safety, developmental, and clinical issues that face families impacted by DV. This paper reviews current approaches to training and the ability of such methods to adequately prepare providers. There are no national standards for providers at any level from DV advocates to batterer interventionists, to clinicians with the required hours of training in most states at an alarmingly low level. Few states require cross training for those working as victim advocates or batterer interventionists. The systems that currently provide segregated and limited training create silos of service that are less effective. A proposed set of standards and training guidelines are proposed for DV advocates, batterer interventionists, and clinicians along with a discussion of the implications of such standards for the field. PMID:25405068

  6. An Integrated Approach Is Needed for Ecosystem Based Fisheries Management: Insights from Ecosystem-Level Management Strategy Evaluation

    PubMed Central

    Fulton, Elizabeth A.; Smith, Anthony D. M.; Smith, David C.; Johnson, Penelope

    2014-01-01

    An ecosystem approach is widely seen as a desirable goal for fisheries management but there is little consensus on what strategies or measures are needed to achieve it. Management strategy evaluation (MSE) is a tool that has been widely used to develop and test single species fisheries management strategies and is now being extended to support ecosystem based fisheries management (EBFM). We describe the application of MSE to investigate alternative strategies for achieving EBFM goals for a complex multispecies fishery in southeastern Australia. The study was undertaken as part of a stakeholder driven process to review and improve the ecological, economic and social performance of the fishery. An integrated management strategy, involving combinations of measures including quotas, gear controls and spatial management, performed best against a wide range of objectives and this strategy was subsequently adopted in the fishery, leading to marked improvements in performance. Although particular to one fishery, the conclusion that an integrated package of measures outperforms single focus measures we argue is likely to apply widely in fisheries that aim to achieve EBFM goals. PMID:24454722

  7. Multiscale causal connectivity analysis by canonical correlation: theory and application to epileptic brain.

    PubMed

    Wu, Guo Rong; Chen, Fuyong; Kang, Dezhi; Zhang, Xiangyang; Marinazzo, Daniele; Chen, Huafu

    2011-11-01

    Multivariate Granger causality is a well-established approach for inferring information flow in complex systems, and it is being increasingly applied to map brain connectivity. Traditional Granger causality is based on vector autoregressive (AR) or mixed autoregressive moving average (ARMA) model, which are potentially affected by errors in parameter estimation and may be contaminated by zero-lag correlation, notably when modeling neuroimaging data. To overcome this issue, we present here an extended canonical correlation approach to measure multivariate Granger causal interactions among time series. The procedure includes a reduced rank step for calculating canonical correlation analysis (CCA), and extends the definition of causality including instantaneous effects, thus avoiding the potential estimation problems of AR (or ARMA) models. We tested this approach on simulated data and confirmed its practical utility by exploring local network connectivity at different scales in the epileptic brain analyzing scalp and depth-EEG data during an interictal period. PMID:21788178

  8. Context and Time in Causal Learning: Contingency and Mood Dependent Effects

    PubMed Central

    Msetfi, Rachel M.; Wade, Caroline; Murphy, Robin A.

    2013-01-01

    Defining cues for instrumental causality are the temporal, spatial and contingency relationships between actions and their effects. In this study, we carried out a series of causal learning experiments that systematically manipulated time and context in positive and negative contingency conditions. In addition, we tested participants categorized as non-dysphoric and mildly dysphoric because depressed mood has been shown to affect the processing of all these causal cues. Findings showed that causal judgements made by non-dysphoric participants were contextualized at baseline and were affected by the temporal spacing of actions and effects only with generative, but not preventative, contingency relationships. Participants categorized as dysphoric made less contextualized causal ratings at baseline but were more sensitive than others to temporal manipulations across the contingencies. These effects were consistent with depression affecting causal learning through the effects of slowed time experience on accrued exposure to the context in which causal events took place. Taken together, these findings are consistent with associative approaches to causal judgement. PMID:23691147

  9. A Nonlinear Causality Estimator Based on Non-Parametric Multiplicative Regression

    PubMed Central

    Nicolaou, Nicoletta; Constandinou, Timothy G.

    2016-01-01

    Causal prediction has become a popular tool for neuroscience applications, as it allows the study of relationships between different brain areas during rest, cognitive tasks or brain disorders. We propose a nonparametric approach for the estimation of nonlinear causal prediction for multivariate time series. In the proposed estimator, CNPMR, Autoregressive modeling is replaced by Nonparametric Multiplicative Regression (NPMR). NPMR quantifies interactions between a response variable (effect) and a set of predictor variables (cause); here, we modified NPMR for model prediction. We also demonstrate how a particular measure, the sensitivity Q, could be used to reveal the structure of the underlying causal relationships. We apply CNPMR on artificial data with known ground truth (5 datasets), as well as physiological data (2 datasets). CNPMR correctly identifies both linear and nonlinear causal connections that are present in the artificial data, as well as physiologically relevant connectivity in the real data, and does not seem to be affected by filtering. The Sensitivity measure also provides useful information about the latent connectivity.The proposed estimator addresses many of the limitations of linear Granger causality and other nonlinear causality estimators. CNPMR is compared with pairwise and conditional Granger causality (linear) and Kernel-Granger causality (nonlinear). The proposed estimator can be applied to pairwise or multivariate estimations without any modifications to the main method. Its nonpametric nature, its ability to capture nonlinear relationships and its robustness to filtering make it appealing for a number of applications. PMID:27378901

  10. Too Much or Not Enough? An Examination of Special Education Provision and School District Leaders' Perceptions of Current Needs and Common Approaches

    ERIC Educational Resources Information Center

    Cameron, David Lansing

    2016-01-01

    The purpose of this study was to examine the relationship between special education provision in Norway and school district leaders' perspectives regarding (a) the need for special education and (b) the importance and prevalence of integrated and segregated approaches. Findings indicate that the percentage of students perceived as being in need of…

  11. A review of causal estimation of effects in mediation analyses.

    PubMed

    Ten Have, Thomas R; Joffe, Marshall M

    2012-02-01

    We describe causal mediation methods for analysing the mechanistic factors through which interventions act on outcomes. A number of different mediation approaches have been presented in the biomedical, social science and statistical literature with an emphasis on different aspects of mediation. We review the different sets of assumptions that allow identification and estimation of effects in the simple case of a single intervention, a temporally subsequent mediator and outcome. These assumptions include various no confounding assumptions including sequential ignorability assumptions and also interaction assumptions involving the treatment and mediator. The understanding of such assumptions is crucial since some can be assessed under certain conditions (e.g. treatment-mediator interactions), whereas others cannot (sequential ignorability). These issues become more complex with multiple mediators and longitudinal outcomes. In addressing these assumptions, we review several causal approaches to mediation analyses. PMID:21163849

  12. Investigations in quantum computing: Causality and graph isomorphism

    NASA Astrophysics Data System (ADS)

    Beckman, David Eugene

    In this thesis I explore two different types of limits on the time complexity of quantum computation---that is, limits on how much time is required to perform a given class of quantum operations on a quantum system. Upper limits can be found by explicit construction; I explore this approach for the problem of determining whether two graphs are isomorphic. Finding lower limits, on the other hand, usually requires appeal to some fundamental principle of the operation under consideration; I use this approach to derive lower limits placed by the requirements of relativistic causality on the time required for implementation of some nonlocal quantum operations. In some situations these limits are attainable, but for other physical spacetime geometries we exhibit classes of operations which do not violate relativistic causality but which are nevertheless not implementable.

  13. Probing the Cultural Constitution of Causal Cognition - A Research Program.

    PubMed

    Bender, Andrea; Beller, Sieghard

    2016-01-01

    To what extent is the way people perceive, represent, and reason about causal relationships dependent on culture? While there have been sporadic attempts to explore this question, a systematic investigation is still lacking. Here, we propose that human causal cognition is not only superficially affected by cultural background, but that it is co-constituted by the cultural nature of the human species. To this end, we take stock of on-going research, with a particular focus on the methodological approaches taken: cross-species comparisons, archeological accounts, developmental studies, cross-cultural, and cross-linguistic experiments, as well as in-depth within-culture analyses of cognitive concepts, processes, and changes over time. We argue that only a combination of these approaches will allow us to integrate different components of cognition, levels of analysis, and points of view-the key requirements for a comprehensive, interdisciplinary research program to advance this field. PMID:26941695

  14. Determining Directional Dependency in Causal Associations

    ERIC Educational Resources Information Center

    Pornprasertmanit, Sunthud; Little, Todd D.

    2012-01-01

    Directional dependency is a method to determine the likely causal direction of effect between two variables. This article aims to critique and improve upon the use of directional dependency as a technique to infer causal associations. We comment on several issues raised by von Eye and DeShon (2012), including: encouraging the use of the signs of…

  15. Updating during Reading Comprehension: Why Causality Matters

    ERIC Educational Resources Information Center

    Kendeou, Panayiota; Smith, Emily R.; O'Brien, Edward J.

    2013-01-01

    The present set of 7 experiments systematically examined the effectiveness of adding causal explanations to simple refutations in reducing or eliminating the impact of outdated information on subsequent comprehension. The addition of a single causal-explanation sentence to a refutation was sufficient to eliminate any measurable disruption in…

  16. Controlling for causally relevant third variables.

    PubMed

    Goodie, Adam S; Williams, Cristina C; Crooks, C L

    2003-10-01

    In 3 experiments, the authors tested the conditions under which 3rd variables are controlled for in making causal judgments. The authors hypothesized that 3rd variables are controlled for when the 3rd variables are themselves perceived as causal. In Experiment 1, the participants predicted test performance after seeing information about wearing a lucky garment, taking a test-preparation course, and staying up late. The course (perceived as more causally relevant) was controlled for more than was the garment (perceived as less causally relevant) in assessing the effectiveness of staying up late. In Experiments 2 and 3, to obviate the many alternative accounts that arise from the realistic cover story of Experiment 1, participants predicted flowers' blooming after the presentation or nonpresentation of liquids. When one liquid was trained as causal, it was controlled for more in judging another liquid than when it was trained as neutral. Overall, stimuli perceived as causal were controlled for more when judging other stimuli. The authors concluded that the effect of perceived causal relevance on causal conditionalizing is real and normatively reasonable. PMID:14672103

  17. Inference and Action in Early Causal Reasoning.

    ERIC Educational Resources Information Center

    Frye, Douglas; And Others

    1996-01-01

    Two marble-and-ramp experiments investigated whether a simple-to-embedded-rules account can explain changes in children's causal reasoning. Results indicated that the same difference between three- and four-year olds in the prediction experiment appeared in the action experiment, suggesting that the same rules may underlie causal action as well as…

  18. A Causal Model of Faculty Research Productivity.

    ERIC Educational Resources Information Center

    Bean, John P.

    A causal model of faculty research productivity was developed through a survey of the literature. Models of organizational behavior, organizational effectiveness, and motivation were synthesized into a causal model of productivity. Two general types of variables were assumed to affect individual research productivity: institutional variables and…

  19. Compact Representations of Extended Causal Models

    ERIC Educational Resources Information Center

    Halpern, Joseph Y.; Hitchcock, Christopher

    2013-01-01

    Judea Pearl (2000) was the first to propose a definition of actual causation using causal models. A number of authors have suggested that an adequate account of actual causation must appeal not only to causal structure but also to considerations of "normality." In Halpern and Hitchcock (2011), we offer a definition of actual causation…

  20. The Acquisition of Causal Connectives in Turkish.

    ERIC Educational Resources Information Center

    Aksu, Ayhan

    The elicited speech of 26 Turkish children ranging in age from 2;0 to 4;6 was examined with respect to causality. The developmental sequence of the acquisition of causal connectives showed a progression from the use of no explicit connectives to the acquisition of connectives that are context-dependent. The next stage in this progression was the…

  1. Causal Inferences during Text Comprehension and Production.

    ERIC Educational Resources Information Center

    Kemper, Susan

    As comprehension failure results whenever readers are unable to infer missing causal connections, recent comprehension research has focused both on assessing the inferential complexity of texts and on investigating students' developing ability to infer causal relationships. Studies have demonstrated that texts rely on four types of causal…

  2. Causal Inferences in the Campbellian Validity System

    ERIC Educational Resources Information Center

    Lund, Thorleif

    2010-01-01

    The purpose of the present paper is to critically examine causal inferences and internal validity as defined by Campbell and co-workers. Several arguments are given against their counterfactual effect definition, and this effect definition should be considered inadequate for causal research in general. Moreover, their defined independence between…

  3. Essays on Causal Inference for Public Policy

    ERIC Educational Resources Information Center

    Zajonc, Tristan

    2012-01-01

    Effective policymaking requires understanding the causal effects of competing proposals. Relevant causal quantities include proposals' expected effect on different groups of recipients, the impact of policies over time, the potential trade-offs between competing objectives, and, ultimately, the optimal policy. This dissertation studies causal…

  4. Preschoolers' Understanding of Temporal and Causal Relations.

    ERIC Educational Resources Information Center

    Sharp, Kay Colby

    1982-01-01

    Two experiments investigated psychological factors determining preschoolers' success or failure on a sequence-completion task involving temporal and causal ordering of events. Overall findings demonstrate that while preschoolers do understand temporal/causal relationships, their abilities are dependent on process variables demanded by the task…

  5. Discovering phenotypic causal structure from nonexperimental data.

    PubMed

    Otsuka, J

    2016-06-01

    The evolutionary potential of organisms depends on how their parts are structured into a cohesive whole. A major obstacle for empirical studies of phenotypic organization is that observed associations among characters usually confound different causal pathways such as pleiotropic modules, interphenotypic causal relationships and environmental effects. The present article proposes causal search algorithms as a new tool to distinguish these different modes of phenotypic integration. Without assuming an a priori structure, the algorithms seek a class of causal hypotheses consistent with independence relationships holding in observational data. The technique can be applied to discover causal relationships among a set of measured traits and to distinguish genuine selection from spurious correlations. The former application is illustrated with a biological data set of rat morphological measurements previously analysed by Cheverud et al. (Evolution 1983, 37, 895). PMID:27007864

  6. Causal Supports for Early Word Learning

    PubMed Central

    Booth, Amy E.

    2009-01-01

    What factors determine whether a young child will learn a new word? Although there are surely numerous contributors, the current investigation highlights the role of causal information. Thirty-six 3-year-old children were taught 6 new words for unfamiliar objects or animals. Items were described in terms of their causal or non-causal properties. When tested only minutes after training, no significant differences between the conditions were evident. However, when tested several days after training, children performed better on words trained in the causal condition. These results demonstrate that the well-documented effect of causal information on learning and categorization extends to word learning in young children. PMID:19630905

  7. Causality, Bell's theorem, and Ontic Definiteness

    NASA Astrophysics Data System (ADS)

    Henson, Joe

    2011-03-01

    Bell's theorem shows that the reasonable relativistic causal principle known as ``local causality'' is not compatible with the predictions of quantum mechanics. It is not possible maintain a satisfying causal principle of this type while dropping any of the better-known assumptions of Bell's theorem. However, another assumption of Bell's theorem is the use of classical logic. One part of this assumption is the principle of ontic definiteness, that is, that it must in principle be possible to assign definite truth values to all propositions treated in the theory. Once the logical setting is clarified somewhat, it can be seen that rejecting this principle does not in any way undermine the type of causal principle used by Bell. Without ontic definiteness, the deterministic causal condition known as Einstein Locality succeeds in banning superluminal influence (including signalling) whilst allowing correlations that violate Bell's inequalities. Objections to altering logic, and the consequences for operational and realistic viewpoints, are also addressed.

  8. Causal effects in psychotherapy: counterfactuals counteract overgeneralization.

    PubMed

    Hofler, Michael; Gloster, Andrew T; Hoyer, Jurgen

    2010-11-01

    Causal inference of psychotherapy effects is usually based on the theory of internal and external validity. The authors argue that as an inductive strategy it often leads to overgeneralization because it promotes neglect of specific clinical boundary conditions (such as practically relevant combinations of treatments, settings, patients, and therapists). Adding the counterfactual conceptualization of causal effects counteracts overgeneralization by considering individuals at a fixed time under two possible treatment conditions as basic units of a causal effect. Consequently, causal effects are regarded as varying in nature as local pieces of a global theory. The authors outline the main deductions from the counterfactual conceptualization with regard to understanding causality, average effects, bias, and study design and address some controversies in psychotherapy research. PMID:20924977

  9. Sensitivity analyses for parametric causal mediation effect estimation.

    PubMed

    Albert, Jeffrey M; Wang, Wei

    2015-04-01

    Causal mediation analysis uses a potential outcomes framework to estimate the direct effect of an exposure on an outcome and its indirect effect through an intermediate variable (or mediator). Causal interpretations of these effects typically rely on sequential ignorability. Because this assumption is not empirically testable, it is important to conduct sensitivity analyses. Sensitivity analyses so far offered for this situation have either focused on the case where the outcome follows a linear model or involve nonparametric or semiparametric models. We propose alternative approaches that are suitable for responses following generalized linear models. The first approach uses a Gaussian copula model involving latent versions of the mediator and the final outcome. The second approach uses a so-called hybrid causal-observational model that extends the association model for the final outcome, providing a novel sensitivity parameter. These models, while still assuming a randomized exposure, allow for unobserved (as well as observed) mediator-outcome confounders that are not affected by exposure. The methods are applied to data from a study of the effect of mother education on dental caries in adolescence. PMID:25395683

  10. Sensitivity analyses for parametric causal mediation effect estimation

    PubMed Central

    Albert, Jeffrey M.; Wang, Wei

    2015-01-01

    Causal mediation analysis uses a potential outcomes framework to estimate the direct effect of an exposure on an outcome and its indirect effect through an intermediate variable (or mediator). Causal interpretations of these effects typically rely on sequential ignorability. Because this assumption is not empirically testable, it is important to conduct sensitivity analyses. Sensitivity analyses so far offered for this situation have either focused on the case where the outcome follows a linear model or involve nonparametric or semiparametric models. We propose alternative approaches that are suitable for responses following generalized linear models. The first approach uses a Gaussian copula model involving latent versions of the mediator and the final outcome. The second approach uses a so-called hybrid causal-observational model that extends the association model for the final outcome, providing a novel sensitivity parameter. These models, while still assuming a randomized exposure, allow for unobserved (as well as observed) mediator-outcome confounders that are not affected by exposure. The methods are applied to data from a study of the effect of mother education on dental caries in adolescence. PMID:25395683

  11. A Multivariate Granger Causality Concept towards Full Brain Functional Connectivity

    PubMed Central

    Schmid-Hertel, Nicole; Witte, Herbert; Wismüller, Axel; Leistritz, Lutz

    2016-01-01

    Detecting changes of spatially high-resolution functional connectivity patterns in the brain is crucial for improving the fundamental understanding of brain function in both health and disease, yet still poses one of the biggest challenges in computational neuroscience. Currently, classical multivariate Granger Causality analyses of directed interactions between single process components in coupled systems are commonly restricted to spatially low- dimensional data, which requires a pre-selection or aggregation of time series as a preprocessing step. In this paper we propose a new fully multivariate Granger Causality approach with embedded dimension reduction that makes it possible to obtain a representation of functional connectivity for spatially high-dimensional data. The resulting functional connectivity networks may consist of several thousand vertices and thus contain more detailed information compared to connectivity networks obtained from approaches based on particular regions of interest. Our large scale Granger Causality approach is applied to synthetic and resting state fMRI data with a focus on how well network community structure, which represents a functional segmentation of the network, is preserved. It is demonstrated that a number of different community detection algorithms, which utilize a variety of algorithmic strategies and exploit topological features differently, reveal meaningful information on the underlying network module structure. PMID:27064897

  12. Improvements in Hudson River Water Quality Create the Need for a new Approach to Monitoring and Management

    NASA Astrophysics Data System (ADS)

    O'Mullan, G. D.; Juhl, A.; Sambrotto, R.; Lipscomb, J.; Brown, T.

    2008-12-01

    localized events, demonstrate that a new approach is needed to monitor and manage the lower Hudson River Estuary. One important component of this new approach is consideration of local and extreme conditions, rather than just spatial and temporal means. Another aspect is increased public dissemination of available water quality data. A new Hudson River water quality web site has been launched as an example of this type of public outreach.

  13. Confounding Effects of Phase Delays on Causality Estimation

    PubMed Central

    Vakorin, Vasily A.; Mišić, Bratislav; Krakovska, Olga; Bezgin, Gleb; McIntosh, Anthony R.

    2013-01-01

    Linear and non-linear techniques for inferring causal relations between the brain signals representing the underlying neuronal systems have become a powerful tool to extract the connectivity patterns in the brain. Typically these tools employ the idea of Granger causality, which is ultimately based on the temporal precedence between the signals. At the same time, phase synchronization between coupled neural ensembles is considered a mechanism implemented in the brain to integrate relevant neuronal ensembles to perform a cognitive or perceptual task. Phase synchronization can be studied by analyzing the effects of phase-locking between the brain signals. However, we should expect that there is no one-to-one mapping between the observed phase lag and the time precedence as specified by physically interacting systems. Specifically, phase lag observed between two signals may interfere with inferring causal relations. This could be of critical importance for the coupled non-linear oscillating systems, with possible time delays in coupling, when classical linear cross-spectrum strategies for solving phase ambiguity are not efficient. To demonstrate this, we used a prototypical model of coupled non-linear systems, and compared three typical pipelines of inferring Granger causality, as established in the literature. Specifically, we compared the performance of the spectral and information-theoretic Granger pipelines as well as standard Granger causality in their relations to the observed phase differences for frequencies at which the signals become synchronized to each other. We found that an information-theoretic approach, which takes into account different time lags between the past of one signal and the future of another signal, was the most robust to phase effects. PMID:23349720

  14. Serum total bilirubin levels and coronary heart disease--Causal association or epiphenomenon?

    PubMed

    Kunutsor, Setor K

    2015-12-01

    Observational epidemiological evidence supports a linear inverse and independent association between serum total bilirubin levels and coronary heart disease (CHD) risk, but whether this association is causal remains to be ascertained. A Mendelian randomization approach was employed to test whether serum total bilirubin is causally linked to CHD. The genetic variant rs6742078--well known to specifically modify levels of serum total bilirubin and accounting for up to 20% of the variance in circulating serum total bilirubin levels--was used as an instrumental variable. In pooled analysis of estimates reported from published genome-wide association studies, every copy of the T allele of rs6742078 was associated with 0.42 standard deviation (SD) higher levels of serum total bilirubin (95% confidence interval, 0.40 to 0.43). Based on combined data from the Coronary Artery Disease Genome wide Replication and Meta-analyses and the Coronary Artery Disease (C4D) Genetics Consortium involving a total of 36,763 CHD cases and 76,997 controls, the odds ratio for CHD per copy of the T allele was 1.01 (95% confidence interval, 0.99 to 1.04). The odds ratio of CHD for a 1 SD genetically elevated serum total bilirubin level was 1.03 (95% confidence interval, 0.98 to 1.09). The current findings casts doubt on a strong causal association of serum total bilirubin levels with CHD. The inverse associations demonstrated in observational studies may be driven by biases such as unmeasured confounding and/or reverse causation. However, further research in large-scale consortia is needed. PMID:26408227

  15. A need for One Health approach – lessons learned from outbreaks of Rift Valley fever in Saudi Arabia and Sudan

    PubMed Central

    Hassan, Osama Ahmed; Ahlm, Clas; Evander, Magnus

    2014-01-01

    Introduction Rift Valley fever (RVF) is an emerging viral zoonosis that impacts human and animal health. It is transmitted from animals to humans directly through exposure to blood, body fluids, or tissues of infected animals or via mosquito bites. The disease is endemic to Africa but has recently spread to Saudi Arabia and Yemen. Our aim was to compare two major outbreaks of RVF in Saudi Arabia (2000) and Sudan (2007) from a One Health perspective. Methods Using the terms ‘Saudi Arabia’, ‘Sudan’, and ‘RVF’, articles were identified by searching PubMed, Google Scholar, and web pages of international organizations as well as local sources in Saudi Arabia and Sudan. Results The outbreak in Saudi Arabia caused 883 human cases, with a case fatality rate of 14% and more than 40,000 dead sheep and goats. In Sudan, 698 human cases of RVF were recognized (case fatality, 31.5%), but no records of affected animals were available. The ecology and environment of the affected areas were similar with irrigation canals and excessive rains providing an attractive habitat for mosquito vectors to multiply. The outbreaks resulted in livestock trade bans leading to a vast economic impact on the animal market in the two countries. The surveillance system in Sudan showed a lack of data management and communication between the regional and federal health authorities, while in Saudi Arabia which is the stronger economy, better capacity and contingency plans resulted in efficient countermeasures. Studies of the epidemiology and vectors were also performed in Saudi Arabia, while in Sudan these issues were only partly studied. Conclusion We conclude that a One Health approach is the best option to mitigate outbreaks of RVF. Collaboration between veterinary, health, and environmental authorities both on national and regional levels is needed. PMID:24505511

  16. Understanding Complexity: Pattern Recognitions, Emergent Phenomena and Causal Coupling

    NASA Astrophysics Data System (ADS)

    Raia, F.

    2010-12-01

    In teaching and learning complex systems we face a fundamental issue: Simultaneity of causal interactions -where effects are at the same time causes of systems’ behavior. Complex systems’ behavior and evolution are controlled by negative and positive feedback processes, continually changing boundary conditions and complex interaction between systems levels (emergence). These processes cannot be described and understood in a mechanistic framework where causality is conceived of being mostly of cause-effect nature or a linear chain of causes and effects. Mechanist causality by definition is characterized by the assumption that an earlier phenomenon A has a causal effect on the development of a phenomenon B. Since this concept also assumes unidirectional time, B cannot have an effect on A. Since students study science mostly in the lingering mechanistic framework, they have problems understanding complex systems. Specifically, our research on students understanding of complexity indicates that our students seem to have great difficulties in explaining mechanisms underlying natural processes within the current paradigm. Students tend to utilize simple linear model of causality and establish a one-to-one correspondence between cause and effect describing phenomena such as emergence and self-organization as being mechanistically caused. Contrary to experts, when presented with data distribution -spatial and/or temporal-, students first consider or search for a unique cause without describing the distribution or a recognized pattern. Our research suggests that students do not consider a pattern observed as an emergent phenomenon and therefore a causal determinant influencing and controlling the evolution of the system. Changes in reasoning have been observed when students 1) are iteratively asked to recognize and describe patterns in data distribution and 2) subsequently learn to identify these patterns as emergent phenomena and as fundamental causal controls over

  17. Attitudes toward Others Depend upon Self and Other Causal Uncertainty

    PubMed Central

    Tobin, Stephanie J.; Osika, Matylda M.; McLanders, Mia

    2014-01-01

    People who are high in causal uncertainty doubt their own ability to understand the causes of social events. In three studies, we examined the effects of target and perceiver causal uncertainty on attitudes toward the target. Target causal uncertainty was manipulated via responses on a causal uncertainty scale in Studies 1 and 2, and with a scenario in Study 3. In Studies 1 and 2, we found that participants liked the low causal uncertainty target more than the high causal uncertainty target. This preference was stronger for low relative to high causal uncertainty participants because high causal uncertainty participants held more uncertain ideals. In Study 3, we examined the value individuals place upon causal understanding (causal importance) as an additional moderator. We found that regardless of their own causal uncertainty level, participants who were high in causal importance liked the low causal uncertainty target more than the high causal uncertainty target. However, when participants were low in causal importance, low causal uncertainty perceivers showed no preference and high causal uncertainty perceivers preferred the high causal uncertainty target. These findings reveal that goal importance and ideals can influence how perceivers respond to causal uncertainty in others. PMID:24504048

  18. Spread of entanglement and causality

    NASA Astrophysics Data System (ADS)

    Casini, Horacio; Liu, Hong; Mezei, Márk

    2016-07-01

    We investigate causality constraints on the time evolution of entanglement entropy after a global quench in relativistic theories. We first provide a general proof that the so-called tsunami velocity is bounded by the speed of light. We then generalize the free particle streaming model of [1] to general dimensions and to an arbitrary entanglement pattern of the initial state. In more than two spacetime dimensions the spread of entanglement in these models is highly sensitive to the initial entanglement pattern, but we are able to prove an upper bound on the normalized rate of growth of entanglement entropy, and hence the tsunami velocity. The bound is smaller than what one gets for quenches in holographic theories, which highlights the importance of interactions in the spread of entanglement in many-body systems. We propose an interacting model which we believe provides an upper bound on the spread of entanglement for interacting relativistic theories. In two spacetime dimensions with multiple intervals, this model and its variations are able to reproduce intricate results exhibited by holographic theories for a significant part of the parameter space. For higher dimensions, the model bounds the tsunami velocity at the speed of light. Finally, we construct a geometric model for entanglement propagation based on a tensor network construction for global quenches.

  19. Causal localizations in relativistic quantum mechanics

    SciTech Connect

    Castrigiano, Domenico P. L. Leiseifer, Andreas D.

    2015-07-15

    Causal localizations describe the position of quantum systems moving not faster than light. They are constructed for the systems with finite spinor dimension. At the center of interest are the massive relativistic systems. For every positive mass, there is the sequence of Dirac tensor-localizations, which provides a complete set of inequivalent irreducible causal localizations. They obey the principle of special relativity and are fully Poincaré covariant. The boosters are determined by the causal position operator and the other Poincaré generators. The localization with minimal spinor dimension is the Dirac localization. Thus, the Dirac equation is derived here as a mere consequence of the principle of causality. Moreover, the higher tensor-localizations, not known so far, follow from Dirac’s localization by a simple construction. The probability of localization for positive energy states results to be described by causal positive operator valued (PO-) localizations, which are the traces of the causal localizations on the subspaces of positive energy. These causal Poincaré covariant PO-localizations for every irreducible massive relativistic system were, all the more, not known before. They are shown to be separated. Hence, the positive energy systems can be localized within every open region by a suitable preparation as accurately as desired. Finally, the attempt is made to provide an interpretation of the PO-localization operators within the frame of conventional quantum mechanics attributing an important role to the negative energy states.

  20. Quantum correlations with no causal order

    PubMed Central

    Oreshkov, Ognyan; Costa, Fabio; Brukner, Časlav

    2012-01-01

    The idea that events obey a definite causal order is deeply rooted in our understanding of the world and at the basis of the very notion of time. But where does causal order come from, and is it a necessary property of nature? Here, we address these questions from the standpoint of quantum mechanics in a new framework for multipartite correlations that does not assume a pre-defined global causal structure but only the validity of quantum mechanics locally. All known situations that respect causal order, including space-like and time-like separated experiments, are captured by this framework in a unified way. Surprisingly, we find correlations that cannot be understood in terms of definite causal order. These correlations violate a 'causal inequality' that is satisfied by all space-like and time-like correlations. We further show that in a classical limit causal order always arises, which suggests that space-time may emerge from a more fundamental structure in a quantum-to-classical transition. PMID:23033068

  1. Causality as individual essence: its bearing on synchronicity.

    PubMed

    Tougas, Cecile T

    2014-06-01

    Causality, time, and number are subjectively lived realities and need to be noticed as such. Fundamental to the wide range of living experience, they are also basic to scientific knowing. In this article I examine causality in relation to an article on synchronicity by Harald Atmanspacher and Wolfgang Fach. My examination is neither scientific nor metaphysical, but rather phenomenological, as it is a clarification of form as individual essence of a thing. This non-material form of an individual thing in the widest sense of the word 'thing' was rejected and so lost during modern seventeenth-century science but, renewed now, can help describe synchronicity. A commentary by William Willeford follows. PMID:24919632

  2. Prediction and causal reasoning in planning

    NASA Technical Reports Server (NTRS)

    Dean, T.; Boddy, M.

    1987-01-01

    Nonlinear planners are often touted as having an efficiency advantage over linear planners. The reason usually given is that nonlinear planners, unlike their linear counterparts, are not forced to make arbitrary commitments to the order in which actions are to be performed. This ability to delay commitment enables nonlinear planners to solve certain problems with far less effort than would be required of linear planners. Here, it is argued that this advantage is bought with a significant reduction in the ability of a nonlinear planner to accurately predict the consequences of actions. Unfortunately, the general problem of predicting the consequences of a partially ordered set of actions is intractable. In gaining the predictive power of linear planners, nonlinear planners sacrifice their efficiency advantage. There are, however, other advantages to nonlinear planning (e.g., the ability to reason about partial orders and incomplete information) that make it well worth the effort needed to extend nonlinear methods. A framework is supplied for causal inference that supports reasoning about partially ordered events and actions whose effects depend upon the context in which they are executed. As an alternative to a complete but potentially exponential-time algorithm, researchers provide a provably sound polynomial-time algorithm for predicting the consequences of partially ordered events.

  3. Maternal smoking and child psychological problems: Disentangling causal and non-causal effects

    PubMed Central

    Brion, Marie-Jo; Victora, Cesar; Matijasevich, Alicia; Horta, Bernardo; Anselmi, Luciana; Steer, Colin; Menezes, Ana Maria B; Lawlor, Debbie A; Smith, George Davey

    2012-01-01

    Objective To explore associations of maternal prenatal smoking and child psychological problems and determine the role of causal intrauterine mechanisms. Patients and Methods Maternal smoking and child psychological problems were explored in 2 birth cohorts in Pelotas, Brazil (n=509; random sub-sample) and Avon Longitudinal Study of Parents and Children (ALSPAC), Britain (n=6,735). Four approaches for exploring causal mechanisms were applied: 1) cross-population comparisons between a high-income and a middle-income country, 2) multiple adjustment for socioeconomic and parental psychological factors, 3) maternal-paternal comparisons as a test of putative intrauterine effects; and 4) search for specific effects on different behavioural subscales. Results Socioeconomic patterning of maternal prenatal smoking was stronger in the ALSPAC compared with the Pelotas cohort. Despite this difference in a key confounder, consistency in observed associations was found between these cohorts. In both cohorts, unadjusted, maternal smoking was associated with greater offspring hyperactivity, conduct/externalizing problems, and peer problems, but not with emotional/internalizing problems. After adjusting for confounders and paternal prenatal smoking, only the association with conduct/externalizing problems persisted in both cohorts (conduct problems in the ALSPAC cohort, odds ratio OR: 1.24 [95% confidence interval (CI): 1.07–1.46], p= .005; externalizing problems in the Pelotas cohort, OR:1.82 [95% CI:1.19–2.78], p=.005; ORs reflect ordinal ORs of maternal smokers having offspring with higher scores). Maternal smoking associations were stronger than paternal smoking associations, although statistical evidence for differences was weak in 1 cohort. Conclusions Evidence from 4 approaches suggests a possible intrauterine effect of maternal smoking on offspring conduct/externalizing problems. PMID:20587678

  4. Causality and momentum conservation from relative locality

    NASA Astrophysics Data System (ADS)

    Amelino-Camelia, Giovanni; Bianco, Stefano; Brighenti, Francesco; Buonocore, Riccardo Junior

    2015-04-01

    Theories involving curved momentum space, which recently became a topic of interest in the quantum-gravity literature, can, in general, violate many apparently robust aspects of our current description of the laws of physics, including relativistic invariance, locality, causality, and global momentum conservation. Here, we explore some aspects of the pathologies arising in generic theories involving curved momentum space for what concerns causality and momentum conservation. However, we also report results suggesting that when momentum space is maximally symmetric, and the theory is formulated relativistically, most notably including translational invariance with the associated relativity of spacetime locality, momentum is globally conserved and there is no violation of causality.

  5. On a renormalization group scheme for causal dynamical triangulations

    NASA Astrophysics Data System (ADS)

    Cooperman, Joshua H.

    2016-03-01

    The causal dynamical triangulations approach aims to construct a quantum theory of gravity as the continuum limit of a lattice-regularized model of dynamical geometry. A renormalization group scheme—in concert with finite size scaling analysis—is essential to this aim. Formulating and implementing such a scheme in the present context raises novel and notable conceptual and technical problems. I explored these problems, and, building on standard techniques, suggested potential solutions in a previous paper (Cooperman, arXiv:gr-qc/1410.0026). As an application of these solutions, I now propose a renormalization group scheme for causal dynamical triangulations. This scheme differs significantly from that studied recently by Ambjørn, Görlich, Jurkiewicz, Kreienbuehl, and Loll.

  6. Causal inference and the data-fusion problem.

    PubMed

    Bareinboim, Elias; Pearl, Judea

    2016-07-01

    We review concepts, principles, and tools that unify current approaches to causal analysis and attend to new challenges presented by big data. In particular, we address the problem of data fusion-piecing together multiple datasets collected under heterogeneous conditions (i.e., different populations, regimes, and sampling methods) to obtain valid answers to queries of interest. The availability of multiple heterogeneous datasets presents new opportunities to big data analysts, because the knowledge that can be acquired from combined data would not be possible from any individual source alone. However, the biases that emerge in heterogeneous environments require new analytical tools. Some of these biases, including confounding, sampling selection, and cross-population biases, have been addressed in isolation, largely in restricted parametric models. We here present a general, nonparametric framework for handling these biases and, ultimately, a theoretical solution to the problem of data fusion in causal inference tasks. PMID:27382148

  7. Causal inference and the data-fusion problem

    PubMed Central

    Bareinboim, Elias; Pearl, Judea

    2016-01-01

    We review concepts, principles, and tools that unify current approaches to causal analysis and attend to new challenges presented by big data. In particular, we address the problem of data fusion—piecing together multiple datasets collected under heterogeneous conditions (i.e., different populations, regimes, and sampling methods) to obtain valid answers to queries of interest. The availability of multiple heterogeneous datasets presents new opportunities to big data analysts, because the knowledge that can be acquired from combined data would not be possible from any individual source alone. However, the biases that emerge in heterogeneous environments require new analytical tools. Some of these biases, including confounding, sampling selection, and cross-population biases, have been addressed in isolation, largely in restricted parametric models. We here present a general, nonparametric framework for handling these biases and, ultimately, a theoretical solution to the problem of data fusion in causal inference tasks. PMID:27382148

  8. Thermodynamic depth of causal states: Objective complexity via minimal representations

    SciTech Connect

    Crutchfield, J.P. |; Shalizi, C.R. |

    1999-01-01

    Thermodynamic depth is an appealing but flawed structural complexity measure. It depends on a set of macroscopic states for a system, but neither its original introduction by Lloyd and Pagels nor any follow-up work has considered how to select these states. Depth, therefore, is at root arbitrary. Computational mechanics, an alternative approach to structural complexity, provides a definition for a system{close_quote}s minimal, necessary causal states and a procedure for finding them. We show that the rate of increase in thermodynamic depth, or {ital dive}, is the system{close_quote}s reverse-time Shannon entropy rate, and so depth only measures degrees of macroscopic randomness, not structure. To fix this, we redefine the depth in terms of the causal state representation{emdash}{epsilon}-machines{emdash}and show that this representation gives the minimum dive consistent with accurate prediction. Thus, {epsilon}-machines are optimally shallow. {copyright} {ital 1999} {ital The American Physical Society}

  9. Causal mediation analysis with a latent mediator.

    PubMed

    Albert, Jeffrey M; Geng, Cuiyu; Nelson, Suchitra

    2016-05-01

    Health researchers are often interested in assessing the direct effect of a treatment or exposure on an outcome variable, as well as its indirect (or mediation) effect through an intermediate variable (or mediator). For an outcome following a nonlinear model, the mediation formula may be used to estimate causally interpretable mediation effects. This method, like others, assumes that the mediator is observed. However, as is common in structural equations modeling, we may wish to consider a latent (unobserved) mediator. We follow a potential outcomes framework and assume a generalized structural equations model (GSEM). We provide maximum-likelihood estimation of GSEM parameters using an approximate Monte Carlo EM algorithm, coupled with a mediation formula approach to estimate natural direct and indirect effects. The method relies on an untestable sequential ignorability assumption; we assess robustness to this assumption by adapting a recently proposed method for sensitivity analysis. Simulation studies show good properties of the proposed estimators in plausible scenarios. Our method is applied to a study of the effect of mother education on occurrence of adolescent dental caries, in which we examine possible mediation through latent oral health behavior. PMID:26363769

  10. Dynamic causal models and autopoietic systems.

    PubMed

    David, Olivier

    2007-01-01

    Dynamic Causal Modelling (DCM) and the theory of autopoietic systems are two important conceptual frameworks. In this review, we suggest that they can be combined to answer important questions about self-organising systems like the brain. DCM has been developed recently by the neuroimaging community to explain, using biophysical models, the non-invasive brain imaging data are caused by neural processes. It allows one to ask mechanistic questions about the implementation of cerebral processes. In DCM the parameters of biophysical models are estimated from measured data and the evidence for each model is evaluated. This enables one to test different functional hypotheses (i.e., models) for a given data set. Autopoiesis and related formal theories of biological systems as autonomous machines represent a body of concepts with many successful applications. However, autopoiesis has remained largely theoretical and has not penetrated the empiricism of cognitive neuroscience. In this review, we try to show the connections that exist between DCM and autopoiesis. In particular, we propose a simple modification to standard formulations of DCM that includes autonomous processes. The idea is to exploit the machinery of the system identification of DCMs in neuroimaging to test the face validity of the autopoietic theory applied to neural subsystems. We illustrate the theoretical concepts and their implications for interpreting electroencephalographic signals acquired during amygdala stimulation in an epileptic patient. The results suggest that DCM represents a relevant biophysical approach to brain functional organisation, with a potential that is yet to be fully evaluated. PMID:18575681

  11. Predicting the Number of Public Computer Terminals Needed for an On-Line Catalog: A Queuing Theory Approach.

    ERIC Educational Resources Information Center

    Knox, A. Whitney; Miller, Bruce A.

    1980-01-01

    Describes a method for estimating the number of cathode ray tube terminals needed for public use of an online library catalog. Authors claim method could also be used to estimate needed numbers of microform readers for a computer output microform (COM) catalog. Formulae are included. (Author/JD)

  12. Untangling Our Web: A Statewide Approach Is Needed to Improve/Judge College Readiness and to Increase College Success

    ERIC Educational Resources Information Center

    Howard-Vital, Michelle Rachel

    2006-01-01

    This paper examines the broad concept of college readiness, the research on advanced placement courses in high schools, and recommends that a statewide effort is needed to increase college readiness, college acclimation, college persistence, and college graduation rates. This effort needs to include a shared vision and the inclusion of multiple…

  13. A Study to Identify the Training Needs of Life Insurance Sales Representatives in Taiwan Using the Delphi Approach

    ERIC Educational Resources Information Center

    Fan, Chiang Ku; Cheng, Chen-Liang

    2006-01-01

    This article reports a study conducted to identify the needs for continuing professional development for life insurance sales representatives and to examine the competencies needed by those sales representatives. A modified Delphi technique was used. Most life insurance companies in the USA implement an education and training plan advocated by the…

  14. A sociodental approach to assessing children's oral health needs: integrating an oral health-related quality of life (OHRQoL) measure into oral health service planning.

    PubMed Central

    Gherunpong, Sudaduang; Sheiham, Aubrey; Tsakos, Georgios

    2006-01-01

    OBJECTIVE: We adopted a sociodental approach to assess the real dental needs of Thai primary school children, and integrated an oral health-related quality of life measure (OHRQoL) into oral health service planning. We then compared the results of this sociodental assessment with standard estimates of a child's oral health needs. METHODS: We developed a new model of sociodental needs assessment and used it to assess the level of impact that various oral health conditions have on the everyday lives of school children. We then carried out a cross-sectional study of all grade-6 children (11-12 years old) in Suphan-buri Province, Thailand. We examined the sample (n = 1034) to assess the children's oral health and then we interviewed each child individually to assess what impact any dental conditions he or she may have on their quality of life. This assessment was done using an OHRQoL indicator, the Child Oral Impacts on Daily Performances index (child-OIDP). We integrated the results obtained using this indicator with those estimates obtained using more traditional, standard clinical methods, in order to generate a clearer picture of exactly which non-progressive dental conditions really needed treatment. These results take into account the impact those conditions have on the overall well-being of children and their ability to function normally and unimpeded. We were then able to prioritize their dental needs according to the severity of disruption caused in their daily lives. FINDINGS: Using standard or "normative" estimates of dental health care needs, the children's need was 98.8%. This level of need decreased signifi cantly to 39.5% when adopting the sociodental approach (P <0.001). Overall, per 100 children with a standard or normative need for dental treatment, only 40 had a sociodental need for treatment when taking into account the impact their condition has on their everyday lives. Children thus identifi ed as requiring treatment were further categorized

  15. A framework for estimating causal effects in latent class analysis: is there a causal link between early sex and subsequent profiles of delinquency?

    PubMed

    Butera, Nicole M; Lanza, Stephanie T; Coffman, Donna L

    2014-06-01

    Prevention scientists use latent class analysis (LCA) with increasing frequency to characterize complex behavior patterns and profiles of risk. Often, the most important research questions in these studies involve establishing characteristics that predict membership in the latent classes, thus describing the composition of the subgroups and suggesting possible points of intervention. More recently, prevention scientists have begun to adopt modern methods for drawing causal inference from observational data because of the bias that can be introduced by confounders. This same issue of confounding exists in any analysis of observational data, including prediction of latent class membership. This study demonstrates a straightforward approach to causal inference in LCA that builds on propensity score methods. We demonstrate this approach by examining the causal effect of early sex on subsequent delinquency latent classes using data from 1,890 adolescents in 11th and 12th grade from wave I of the National Longitudinal Study of Adolescent Health. Prior to the statistical adjustment for potential confounders, early sex was significantly associated with delinquency latent class membership for both genders (p = 0.02). However, the propensity score adjusted analysis indicated no evidence for a causal effect of early sex on delinquency class membership (p = 0.76) for either gender. Sample R and SAS code is included in an Appendix in the ESM so that prevention scientists may adopt this approach to causal inference in LCA in their own work. PMID:23839479

  16. Drawing Causal Inferences Using Propensity Scores: A Practical Guide for Community Psychologists

    PubMed Central

    Lanza, Stephanie T.; Moore, Julia E.; Butera, Nicole M.

    2014-01-01

    Confounding present in observational data impede community psychologists’ ability to draw causal inferences. This paper describes propensity score methods as a conceptually straightforward approach to drawing causal inferences from observational data. A step-by-step demonstration of three propensity score methods – weighting, matching, and subclassification – is presented in the context of an empirical examination of the causal effect of preschool experiences (Head Start vs. parental care) on reading development in kindergarten. Although the unadjusted population estimate indicated that children with parental care had substantially higher reading scores than children who attended Head Start, all propensity score adjustments reduce the size of this overall causal effect by more than half. The causal effect was also defined and estimated among children who attended Head Start. Results provide no evidence for improved reading if those children had instead received parental care. We carefully define different causal effects and discuss their respective policy implications, summarize advantages and limitations of each propensity score method, and provide SAS and R syntax so that community psychologists may conduct causal inference in their own research. PMID:24185755

  17. Quantifying information transfer and mediation along causal pathways in complex systems

    NASA Astrophysics Data System (ADS)

    Runge, Jakob

    2015-12-01

    Measures of information transfer have become a popular approach to analyze interactions in complex systems such as the Earth or the human brain from measured time series. Recent work has focused on causal definitions of information transfer aimed at decompositions of predictive information about a target variable, while excluding effects of common drivers and indirect influences. While common drivers clearly constitute a spurious causality, the aim of the present article is to develop measures quantifying different notions of the strength of information transfer along indirect causal paths, based on first reconstructing the multivariate causal network. Another class of novel measures quantifies to what extent different intermediate processes on causal paths contribute to an interaction mechanism to determine pathways of causal information transfer. The proposed framework complements predictive decomposition schemes by focusing more on the interaction mechanism between multiple processes. A rigorous mathematical framework allows for a clear information-theoretic interpretation that can also be related to the underlying dynamics as proven for certain classes of processes. Generally, however, estimates of information transfer remain hard to interpret for nonlinearly intertwined complex systems. But if experiments or mathematical models are not available, then measuring pathways of information transfer within the causal dependency structure allows at least for an abstraction of the dynamics. The measures are illustrated on a climatological example to disentangle pathways of atmospheric flow over Europe.

  18. Causally-Rich Group Play: A Powerful Context for Building Preschoolers’ Vocabulary

    PubMed Central

    Bauer, Jessie Raye; Booth, Amy E.; McGroarty-Torres, Kathleen

    2016-01-01

    This work explores whether the facilitative effect of causal information on preschoolers’ word learning observed in the laboratory might be relevant to boosting children’s vocabulary in a group-play context. Forty-eight 3- to 4-year-old children learned six novel words for novel tools introduced during a small group-play session. Half of the groups used the tools according to their specified function to construct a fruit salad. The remaining children used the same tools to decorate a castle of blocks. In this way, some children learned about the causal properties of the tools, while others did not. Although children in both conditions comprehended the novel words equally well when tested shortly after the play session, learning in the Causal condition was more robust. Children’s comprehension scores in the Causal condition increased over time (a 7–20 day delay), such that children in this group performed better than children in the Non-Causal condition when tested in a follow-up session. These results demonstrate a striking benefit of causal enrichment to word learning in a context that could feasibly be implemented in preschool classrooms, playgroups, and individual households. Highlighting the causal properties of objects during playtime might offer a powerful approach to building children’s vocabulary, thereby providing a stronger foundation for early literacy and success in school more generally speaking. PMID:27445951

  19. Causally-Rich Group Play: A Powerful Context for Building Preschoolers' Vocabulary.

    PubMed

    Bauer, Jessie Raye; Booth, Amy E; McGroarty-Torres, Kathleen

    2016-01-01

    This work explores whether the facilitative effect of causal information on preschoolers' word learning observed in the laboratory might be relevant to boosting children's vocabulary in a group-play context. Forty-eight 3- to 4-year-old children learned six novel words for novel tools introduced during a small group-play session. Half of the groups used the tools according to their specified function to construct a fruit salad. The remaining children used the same tools to decorate a castle of blocks. In this way, some children learned about the causal properties of the tools, while others did not. Although children in both conditions comprehended the novel words equally well when tested shortly after the play session, learning in the Causal condition was more robust. Children's comprehension scores in the Causal condition increased over time (a 7-20 day delay), such that children in this group performed better than children in the Non-Causal condition when tested in a follow-up session. These results demonstrate a striking benefit of causal enrichment to word learning in a context that could feasibly be implemented in preschool classrooms, playgroups, and individual households. Highlighting the causal properties of objects during playtime might offer a powerful approach to building children's vocabulary, thereby providing a stronger foundation for early literacy and success in school more generally speaking. PMID:27445951

  20. Quantifying information transfer and mediation along causal pathways in complex systems.

    PubMed

    Runge, Jakob

    2015-12-01

    Measures of information transfer have become a popular approach to analyze interactions in complex systems such as the Earth or the human brain from measured time series. Recent work has focused on causal definitions of information transfer aimed at decompositions of predictive information about a target variable, while excluding effects of common drivers and indirect influences. While common drivers clearly constitute a spurious causality, the aim of the present article is to develop measures quantifying different notions of the strength of information transfer along indirect causal paths, based on first reconstructing the multivariate causal network. Another class of novel measures quantifies to what extent different intermediate processes on causal paths contribute to an interaction mechanism to determine pathways of causal information transfer. The proposed framework complements predictive decomposition schemes by focusing more on the interaction mechanism between multiple processes. A rigorous mathematical framework allows for a clear information-theoretic interpretation that can also be related to the underlying dynamics as proven for certain classes of processes. Generally, however, estimates of information transfer remain hard to interpret for nonlinearly intertwined complex systems. But if experiments or mathematical models are not available, then measuring pathways of information transfer within the causal dependency structure allows at least for an abstraction of the dynamics. The measures are illustrated on a climatological example to disentangle pathways of atmospheric flow over Europe. PMID:26764766