Classifying next-generation sequencing data using a zero-inflated Poisson model.

PubMed

Zhou, Yan; Wan, Xiang; Zhang, Baoxue; Tong, Tiejun

2018-04-15

With the development of high-throughput techniques, RNA-sequencing (RNA-seq) is becoming increasingly popular as an alternative for gene expression analysis, such as RNAs profiling and classification. Identifying which type of diseases a new patient belongs to with RNA-seq data has been recognized as a vital problem in medical research. As RNA-seq data are discrete, statistical methods developed for classifying microarray data cannot be readily applied for RNA-seq data classification. Witten proposed a Poisson linear discriminant analysis (PLDA) to classify the RNA-seq data in 2011. Note, however, that the count datasets are frequently characterized by excess zeros in real RNA-seq or microRNA sequence data (i.e. when the sequence depth is not enough or small RNAs with the length of 18-30 nucleotides). Therefore, it is desired to develop a new model to analyze RNA-seq data with an excess of zeros. In this paper, we propose a Zero-Inflated Poisson Logistic Discriminant Analysis (ZIPLDA) for RNA-seq data with an excess of zeros. The new method assumes that the data are from a mixture of two distributions: one is a point mass at zero, and the other follows a Poisson distribution. We then consider a logistic relation between the probability of observing zeros and the mean of the genes and the sequencing depth in the model. Simulation studies show that the proposed method performs better than, or at least as well as, the existing methods in a wide range of settings. Two real datasets including a breast cancer RNA-seq dataset and a microRNA-seq dataset are also analyzed, and they coincide with the simulation results that our proposed method outperforms the existing competitors. The software is available at http://www.math.hkbu.edu.hk/∼tongt. xwan@comp.hkbu.edu.hk or tongt@hkbu.edu.hk. Supplementary data are available at Bioinformatics online.

Analyzing hospitalization data: potential limitations of Poisson regression.

PubMed

Weaver, Colin G; Ravani, Pietro; Oliver, Matthew J; Austin, Peter C; Quinn, Robert R

2015-08-01

Poisson regression is commonly used to analyze hospitalization data when outcomes are expressed as counts (e.g. number of days in hospital). However, data often violate the assumptions on which Poisson regression is based. More appropriate extensions of this model, while available, are rarely used. We compared hospitalization data between 206 patients treated with hemodialysis (HD) and 107 treated with peritoneal dialysis (PD) using Poisson regression and compared results from standard Poisson regression with those obtained using three other approaches for modeling count data: negative binomial (NB) regression, zero-inflated Poisson (ZIP) regression and zero-inflated negative binomial (ZINB) regression. We examined the appropriateness of each model and compared the results obtained with each approach. During a mean 1.9 years of follow-up, 183 of 313 patients (58%) were never hospitalized (indicating an excess of 'zeros'). The data also displayed overdispersion (variance greater than mean), violating another assumption of the Poisson model. Using four criteria, we determined that the NB and ZINB models performed best. According to these two models, patients treated with HD experienced similar hospitalization rates as those receiving PD {NB rate ratio (RR): 1.04 [bootstrapped 95% confidence interval (CI): 0.49-2.20]; ZINB summary RR: 1.21 (bootstrapped 95% CI 0.60-2.46)}. Poisson and ZIP models fit the data poorly and had much larger point estimates than the NB and ZINB models [Poisson RR: 1.93 (bootstrapped 95% CI 0.88-4.23); ZIP summary RR: 1.84 (bootstrapped 95% CI 0.88-3.84)]. We found substantially different results when modeling hospitalization data, depending on the approach used. Our results argue strongly for a sound model selection process and improved reporting around statistical methods used for modeling count data. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

EM Adaptive LASSO—A Multilocus Modeling Strategy for Detecting SNPs Associated with Zero-inflated Count Phenotypes

PubMed Central

Mallick, Himel; Tiwari, Hemant K.

2016-01-01

Count data are increasingly ubiquitous in genetic association studies, where it is possible to observe excess zero counts as compared to what is expected based on standard assumptions. For instance, in rheumatology, data are usually collected in multiple joints within a person or multiple sub-regions of a joint, and it is not uncommon that the phenotypes contain enormous number of zeroes due to the presence of excessive zero counts in majority of patients. Most existing statistical methods assume that the count phenotypes follow one of these four distributions with appropriate dispersion-handling mechanisms: Poisson, Zero-inflated Poisson (ZIP), Negative Binomial, and Zero-inflated Negative Binomial (ZINB). However, little is known about their implications in genetic association studies. Also, there is a relative paucity of literature on their usefulness with respect to model misspecification and variable selection. In this article, we have investigated the performance of several state-of-the-art approaches for handling zero-inflated count data along with a novel penalized regression approach with an adaptive LASSO penalty, by simulating data under a variety of disease models and linkage disequilibrium patterns. By taking into account data-adaptive weights in the estimation procedure, the proposed method provides greater flexibility in multi-SNP modeling of zero-inflated count phenotypes. A fast coordinate descent algorithm nested within an EM (expectation-maximization) algorithm is implemented for estimating the model parameters and conducting variable selection simultaneously. Results show that the proposed method has optimal performance in the presence of multicollinearity, as measured by both prediction accuracy and empirical power, which is especially apparent as the sample size increases. Moreover, the Type I error rates become more or less uncontrollable for the competing methods when a model is misspecified, a phenomenon routinely encountered in practice

EM Adaptive LASSO-A Multilocus Modeling Strategy for Detecting SNPs Associated with Zero-inflated Count Phenotypes.

PubMed

Mallick, Himel; Tiwari, Hemant K

2016-01-01

Count data are increasingly ubiquitous in genetic association studies, where it is possible to observe excess zero counts as compared to what is expected based on standard assumptions. For instance, in rheumatology, data are usually collected in multiple joints within a person or multiple sub-regions of a joint, and it is not uncommon that the phenotypes contain enormous number of zeroes due to the presence of excessive zero counts in majority of patients. Most existing statistical methods assume that the count phenotypes follow one of these four distributions with appropriate dispersion-handling mechanisms: Poisson, Zero-inflated Poisson (ZIP), Negative Binomial, and Zero-inflated Negative Binomial (ZINB). However, little is known about their implications in genetic association studies. Also, there is a relative paucity of literature on their usefulness with respect to model misspecification and variable selection. In this article, we have investigated the performance of several state-of-the-art approaches for handling zero-inflated count data along with a novel penalized regression approach with an adaptive LASSO penalty, by simulating data under a variety of disease models and linkage disequilibrium patterns. By taking into account data-adaptive weights in the estimation procedure, the proposed method provides greater flexibility in multi-SNP modeling of zero-inflated count phenotypes. A fast coordinate descent algorithm nested within an EM (expectation-maximization) algorithm is implemented for estimating the model parameters and conducting variable selection simultaneously. Results show that the proposed method has optimal performance in the presence of multicollinearity, as measured by both prediction accuracy and empirical power, which is especially apparent as the sample size increases. Moreover, the Type I error rates become more or less uncontrollable for the competing methods when a model is misspecified, a phenomenon routinely encountered in practice.

Determinants of The Grade A Embryos in Infertile Women; Zero-Inflated Regression Model.

PubMed

Almasi-Hashiani, Amir; Ghaheri, Azadeh; Omani Samani, Reza

2017-10-01

In assisted reproductive technology, it is important to choose high quality embryos for embryo transfer. The aim of the present study was to determine the grade A embryo count and factors related to it in infertile women. This historical cohort study included 996 infertile women. The main outcome was the number of grade A embryos. Zero-Inflated Poisson (ZIP) regression and Zero-Inflated Negative Binomial (ZINB) regression were used to model the count data as it contained excessive zeros. Stata software, version 13 (Stata Corp, College Station, TX, USA) was used for all statistical analyses. After adjusting for potential confounders, results from the ZINB model show that for each unit increase in the number 2 pronuclear (2PN) zygotes, we get an increase of 1.45 times as incidence rate ratio (95% confidence interval (CI): 1.23-1.69, P=0.001) in the expected grade A embryo count number, and for each increase in the cleavage day we get a decrease 0.35 times (95% CI: 0.20-0.61, P=0.001) in expected grade A embryo count. There is a significant association between both the number of 2PN zygotes and cleavage day with the number of grade A embryos in both ZINB and ZIP regression models. The estimated coefficients are more plausible than values found in earlier studies using less relevant models. Copyright© by Royan Institute. All rights reserved.

Semiparametric bivariate zero-inflated Poisson models with application to studies of abundance for multiple species

USGS Publications Warehouse

Arab, Ali; Holan, Scott H.; Wikle, Christopher K.; Wildhaber, Mark L.

2012-01-01

Ecological studies involving counts of abundance, presence–absence or occupancy rates often produce data having a substantial proportion of zeros. Furthermore, these types of processes are typically multivariate and only adequately described by complex nonlinear relationships involving externally measured covariates. Ignoring these aspects of the data and implementing standard approaches can lead to models that fail to provide adequate scientific understanding of the underlying ecological processes, possibly resulting in a loss of inferential power. One method of dealing with data having excess zeros is to consider the class of univariate zero-inflated generalized linear models. However, this class of models fails to address the multivariate and nonlinear aspects associated with the data usually encountered in practice. Therefore, we propose a semiparametric bivariate zero-inflated Poisson model that takes into account both of these data attributes. The general modeling framework is hierarchical Bayes and is suitable for a broad range of applications. We demonstrate the effectiveness of our model through a motivating example on modeling catch per unit area for multiple species using data from the Missouri River Benthic Fishes Study, implemented by the United States Geological Survey.

Mapping species abundance by a spatial zero-inflated Poisson model: a case study in the Wadden Sea, the Netherlands.

PubMed

Lyashevska, Olga; Brus, Dick J; van der Meer, Jaap

2016-01-01

The objective of the study was to provide a general procedure for mapping species abundance when data are zero-inflated and spatially correlated counts. The bivalve species Macoma balthica was observed on a 500×500 m grid in the Dutch part of the Wadden Sea. In total, 66% of the 3451 counts were zeros. A zero-inflated Poisson mixture model was used to relate counts to environmental covariates. Two models were considered, one with relatively fewer covariates (model "small") than the other (model "large"). The models contained two processes: a Bernoulli (species prevalence) and a Poisson (species intensity, when the Bernoulli process predicts presence). The model was used to make predictions for sites where only environmental data are available. Predicted prevalences and intensities show that the model "small" predicts lower mean prevalence and higher mean intensity, than the model "large". Yet, the product of prevalence and intensity, which might be called the unconditional intensity, is very similar. Cross-validation showed that the model "small" performed slightly better, but the difference was small. The proposed methodology might be generally applicable, but is computer intensive.

Modeling animal-vehicle collisions using diagonal inflated bivariate Poisson regression.

PubMed

Lao, Yunteng; Wu, Yao-Jan; Corey, Jonathan; Wang, Yinhai

2011-01-01

Two types of animal-vehicle collision (AVC) data are commonly adopted for AVC-related risk analysis research: reported AVC data and carcass removal data. One issue with these two data sets is that they were found to have significant discrepancies by previous studies. In order to model these two types of data together and provide a better understanding of highway AVCs, this study adopts a diagonal inflated bivariate Poisson regression method, an inflated version of bivariate Poisson regression model, to fit the reported AVC and carcass removal data sets collected in Washington State during 2002-2006. The diagonal inflated bivariate Poisson model not only can model paired data with correlation, but also handle under- or over-dispersed data sets as well. Compared with three other types of models, double Poisson, bivariate Poisson, and zero-inflated double Poisson, the diagonal inflated bivariate Poisson model demonstrates its capability of fitting two data sets with remarkable overlapping portions resulting from the same stochastic process. Therefore, the diagonal inflated bivariate Poisson model provides researchers a new approach to investigating AVCs from a different perspective involving the three distribution parameters (λ(1), λ(2) and λ(3)). The modeling results show the impacts of traffic elements, geometric design and geographic characteristics on the occurrences of both reported AVC and carcass removal data. It is found that the increase of some associated factors, such as speed limit, annual average daily traffic, and shoulder width, will increase the numbers of reported AVCs and carcass removals. Conversely, the presence of some geometric factors, such as rolling and mountainous terrain, will decrease the number of reported AVCs. Published by Elsevier Ltd.

Full Bayes Poisson gamma, Poisson lognormal, and zero inflated random effects models: Comparing the precision of crash frequency estimates.

PubMed

Aguero-Valverde, Jonathan

2013-01-01

In recent years, complex statistical modeling approaches have being proposed to handle the unobserved heterogeneity and the excess of zeros frequently found in crash data, including random effects and zero inflated models. This research compares random effects, zero inflated, and zero inflated random effects models using a full Bayes hierarchical approach. The models are compared not just in terms of goodness-of-fit measures but also in terms of precision of posterior crash frequency estimates since the precision of these estimates is vital for ranking of sites for engineering improvement. Fixed-over-time random effects models are also compared to independent-over-time random effects models. For the crash dataset being analyzed, it was found that once the random effects are included in the zero inflated models, the probability of being in the zero state is drastically reduced, and the zero inflated models degenerate to their non zero inflated counterparts. Also by fixing the random effects over time the fit of the models and the precision of the crash frequency estimates are significantly increased. It was found that the rankings of the fixed-over-time random effects models are very consistent among them. In addition, the results show that by fixing the random effects over time, the standard errors of the crash frequency estimates are significantly reduced for the majority of the segments on the top of the ranking. Copyright © 2012 Elsevier Ltd. All rights reserved.

Zero-inflated count models for longitudinal measurements with heterogeneous random effects.

PubMed

Zhu, Huirong; Luo, Sheng; DeSantis, Stacia M

2017-08-01

Longitudinal zero-inflated count data arise frequently in substance use research when assessing the effects of behavioral and pharmacological interventions. Zero-inflated count models (e.g. zero-inflated Poisson or zero-inflated negative binomial) with random effects have been developed to analyze this type of data. In random effects zero-inflated count models, the random effects covariance matrix is typically assumed to be homogeneous (constant across subjects). However, in many situations this matrix may be heterogeneous (differ by measured covariates). In this paper, we extend zero-inflated count models to account for random effects heterogeneity by modeling their variance as a function of covariates. We show via simulation that ignoring intervention and covariate-specific heterogeneity can produce biased estimates of covariate and random effect estimates. Moreover, those biased estimates can be rectified by correctly modeling the random effects covariance structure. The methodological development is motivated by and applied to the Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence (COMBINE) study, the largest clinical trial of alcohol dependence performed in United States with 1383 individuals.

Marginal regression models for clustered count data based on zero-inflated Conway-Maxwell-Poisson distribution with applications.

PubMed

Choo-Wosoba, Hyoyoung; Levy, Steven M; Datta, Somnath

2016-06-01

Community water fluoridation is an important public health measure to prevent dental caries, but it continues to be somewhat controversial. The Iowa Fluoride Study (IFS) is a longitudinal study on a cohort of Iowa children that began in 1991. The main purposes of this study (http://www.dentistry.uiowa.edu/preventive-fluoride-study) were to quantify fluoride exposures from both dietary and nondietary sources and to associate longitudinal fluoride exposures with dental fluorosis (spots on teeth) and dental caries (cavities). We analyze a subset of the IFS data by a marginal regression model with a zero-inflated version of the Conway-Maxwell-Poisson distribution for count data exhibiting excessive zeros and a wide range of dispersion patterns. In general, we introduce two estimation methods for fitting a ZICMP marginal regression model. Finite sample behaviors of the estimators and the resulting confidence intervals are studied using extensive simulation studies. We apply our methodologies to the dental caries data. Our novel modeling incorporating zero inflation, clustering, and overdispersion sheds some new light on the effect of community water fluoridation and other factors. We also include a second application of our methodology to a genomic (next-generation sequencing) dataset that exhibits underdispersion. © 2015, The International Biometric Society.

Marginalized zero-inflated negative binomial regression with application to dental caries

PubMed Central

Preisser, John S.; Das, Kalyan; Long, D. Leann; Divaris, Kimon

2015-01-01

The zero-inflated negative binomial regression model (ZINB) is often employed in diverse fields such as dentistry, health care utilization, highway safety, and medicine to examine relationships between exposures of interest and overdispersed count outcomes exhibiting many zeros. The regression coefficients of ZINB have latent class interpretations for a susceptible subpopulation at risk for the disease/condition under study with counts generated from a negative binomial distribution and for a non-susceptible subpopulation that provides only zero counts. The ZINB parameters, however, are not well-suited for estimating overall exposure effects, specifically, in quantifying the effect of an explanatory variable in the overall mixture population. In this paper, a marginalized zero-inflated negative binomial regression (MZINB) model for independent responses is proposed to model the population marginal mean count directly, providing straightforward inference for overall exposure effects based on maximum likelihood estimation. Through simulation studies, the finite sample performance of MZINB is compared to marginalized zero-inflated Poisson, Poisson, and negative binomial regression. The MZINB model is applied in the evaluation of a school-based fluoride mouthrinse program on dental caries in 677 children. PMID:26568034

Modeling Zero-Inflated and Overdispersed Count Data: An Empirical Study of School Suspensions

ERIC Educational Resources Information Center

Desjardins, Christopher David

2016-01-01

The purpose of this article is to develop a statistical model that best explains variability in the number of school days suspended. Number of school days suspended is a count variable that may be zero-inflated and overdispersed relative to a Poisson model. Four models were examined: Poisson, negative binomial, Poisson hurdle, and negative…

Zero-inflated modeling of fish catch per unit area resulting from multiple gears: Application to channel catfish and shovelnose sturgeon in the Missouri River

USGS Publications Warehouse

Arab, A.; Wildhaber, M.L.; Wikle, C.K.; Gentry, C.N.

2008-01-01

Fisheries studies often employ multiple gears that result in large percentages of zero values. We considered a zero-inflated Poisson (ZIP) model with random effects to address these excessive zeros. By employing a Bayesian ZIP model that simultaneously incorporates data from multiple gears to analyze data from the Missouri River, we were able to compare gears and make more year, segment, and macrohabitat comparisons than did the original data analysis. For channel catfish Ictalurus punctatus, our results rank (highest to lowest) the mean catch per unit area (CPUA) for gears (beach seine, benthic trawl, electrofishing, and drifting trammel net); years (1998 and 1997); macrohabitats (tributary mouth, connected secondary channel, nonconnected secondary channel, and bend); and river segment zones (channelized, inter-reservoir, and least-altered). For shovelnose sturgeon Scaphirhynchus platorynchus, the mean CPUA was significantly higher for benthic trawls and drifting trammel nets; 1998 and 1997; tributary mouths, bends, and connected secondary channels; and some channelized or least-altered inter-reservoir segments. One important advantage of our approach is the ability to reliably infer patterns of relative abundance by means of multiple gears without using gear efficiencies. ?? Copyright by the American Fisheries Society 2008.

Cumulative sum control charts for monitoring geometrically inflated Poisson processes: An application to infectious disease counts data.

PubMed

Rakitzis, Athanasios C; Castagliola, Philippe; Maravelakis, Petros E

2018-02-01

In this work, we study upper-sided cumulative sum control charts that are suitable for monitoring geometrically inflated Poisson processes. We assume that a process is properly described by a two-parameter extension of the zero-inflated Poisson distribution, which can be used for modeling count data with an excessive number of zero and non-zero values. Two different upper-sided cumulative sum-type schemes are considered, both suitable for the detection of increasing shifts in the average of the process. Aspects of their statistical design are discussed and their performance is compared under various out-of-control situations. Changes in both parameters of the process are considered. Finally, the monitoring of the monthly cases of poliomyelitis in the USA is given as an illustrative example.

Some findings on zero-inflated and hurdle poisson models for disease mapping.

PubMed

Corpas-Burgos, Francisca; García-Donato, Gonzalo; Martinez-Beneito, Miguel A

2018-05-27

Zero excess in the study of geographically referenced mortality data sets has been the focus of considerable attention in the literature, with zero-inflation being the most common procedure to handle this lack of fit. Although hurdle models have also been used in disease mapping studies, their use is more rare. We show in this paper that models using particular treatments of zero excesses are often required for achieving appropriate fits in regular mortality studies since, otherwise, geographical units with low expected counts are oversmoothed. However, as also shown, an indiscriminate treatment of zero excess may be unnecessary and has a problematic implementation. In this regard, we find that naive zero-inflation and hurdle models, without an explicit modeling of the probabilities of zeroes, do not fix zero excesses problems well enough and are clearly unsatisfactory. Results sharply suggest the need for an explicit modeling of the probabilities that should vary across areal units. Unfortunately, these more flexible modeling strategies can easily lead to improper posterior distributions as we prove in several theoretical results. Those procedures have been repeatedly used in the disease mapping literature, and one should bear these issues in mind in order to propose valid models. We finally propose several valid modeling alternatives according to the results mentioned that are suitable for fitting zero excesses. We show that those proposals fix zero excesses problems and correct the mentioned oversmoothing of risks in low populated units depicting geographic patterns more suited to the data. Copyright © 2018 John Wiley & Sons, Ltd.

Hurdle models for multilevel zero-inflated data via h-likelihood.

PubMed

Molas, Marek; Lesaffre, Emmanuel

2010-12-30

Count data often exhibit overdispersion. One type of overdispersion arises when there is an excess of zeros in comparison with the standard Poisson distribution. Zero-inflated Poisson and hurdle models have been proposed to perform a valid likelihood-based analysis to account for the surplus of zeros. Further, data often arise in clustered, longitudinal or multiple-membership settings. The proper analysis needs to reflect the design of a study. Typically random effects are used to account for dependencies in the data. We examine the h-likelihood estimation and inference framework for hurdle models with random effects for complex designs. We extend the h-likelihood procedures to fit hurdle models, thereby extending h-likelihood to truncated distributions. Two applications of the methodology are presented. Copyright © 2010 John Wiley & Sons, Ltd.

Modeling Tetanus Neonatorum case using the regression of negative binomial and zero-inflated negative binomial

NASA Astrophysics Data System (ADS)

Amaliana, Luthfatul; Sa'adah, Umu; Wayan Surya Wardhani, Ni

2017-12-01

Tetanus Neonatorum is an infectious disease that can be prevented by immunization. The number of Tetanus Neonatorum cases in East Java Province is the highest in Indonesia until 2015. Tetanus Neonatorum data contain over dispersion and big enough proportion of zero-inflation. Negative Binomial (NB) regression is an alternative method when over dispersion happens in Poisson regression. However, the data containing over dispersion and zero-inflation are more appropriately analyzed by using Zero-Inflated Negative Binomial (ZINB) regression. The purpose of this study are: (1) to model Tetanus Neonatorum cases in East Java Province with 71.05 percent proportion of zero-inflation by using NB and ZINB regression, (2) to obtain the best model. The result of this study indicates that ZINB is better than NB regression with smaller AIC.

Growth Curve Models for Zero-Inflated Count Data: An Application to Smoking Behavior

ERIC Educational Resources Information Center

Liu, Hui; Powers, Daniel A.

2007-01-01

This article applies growth curve models to longitudinal count data characterized by an excess of zero counts. We discuss a zero-inflated Poisson regression model for longitudinal data in which the impact of covariates on the initial counts and the rate of change in counts over time is the focus of inference. Basic growth curve models using a…

Variable selection for distribution-free models for longitudinal zero-inflated count responses.

PubMed

Chen, Tian; Wu, Pan; Tang, Wan; Zhang, Hui; Feng, Changyong; Kowalski, Jeanne; Tu, Xin M

2016-07-20

Zero-inflated count outcomes arise quite often in research and practice. Parametric models such as the zero-inflated Poisson and zero-inflated negative binomial are widely used to model such responses. Like most parametric models, they are quite sensitive to departures from assumed distributions. Recently, new approaches have been proposed to provide distribution-free, or semi-parametric, alternatives. These methods extend the generalized estimating equations to provide robust inference for population mixtures defined by zero-inflated count outcomes. In this paper, we propose methods to extend smoothly clipped absolute deviation (SCAD)-based variable selection methods to these new models. Variable selection has been gaining popularity in modern clinical research studies, as determining differential treatment effects of interventions for different subgroups has become the norm, rather the exception, in the era of patent-centered outcome research. Such moderation analysis in general creates many explanatory variables in regression analysis, and the advantages of SCAD-based methods over their traditional counterparts render them a great choice for addressing this important and timely issues in clinical research. We illustrate the proposed approach with both simulated and real study data. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

New variable selection methods for zero-inflated count data with applications to the substance abuse field

PubMed Central

Buu, Anne; Johnson, Norman J.; Li, Runze; Tan, Xianming

2011-01-01

Zero-inflated count data are very common in health surveys. This study develops new variable selection methods for the zero-inflated Poisson regression model. Our simulations demonstrate the negative consequences which arise from the ignorance of zero-inflation. Among the competing methods, the one-step SCAD method is recommended because it has the highest specificity, sensitivity, exact fit, and lowest estimation error. The design of the simulations is based on the special features of two large national databases commonly used in the alcoholism and substance abuse field so that our findings can be easily generalized to the real settings. Applications of the methodology are demonstrated by empirical analyses on the data from a well-known alcohol study. PMID:21563207

Modeling health survey data with excessive zero and K responses.

PubMed

Lin, Ting Hsiang; Tsai, Min-Hsiao

2013-04-30

Zero-inflated Poisson regression is a popular tool used to analyze data with excessive zeros. Although much work has already been performed to fit zero-inflated data, most models heavily depend on special features of the individual data. To be specific, this means that there is a sizable group of respondents who endorse the same answers making the data have peaks. In this paper, we propose a new model with the flexibility to model excessive counts other than zero, and the model is a mixture of multinomial logistic and Poisson regression, in which the multinomial logistic component models the occurrence of excessive counts, including zeros, K (where K is a positive integer) and all other values. The Poisson regression component models the counts that are assumed to follow a Poisson distribution. Two examples are provided to illustrate our models when the data have counts containing many ones and sixes. As a result, the zero-inflated and K-inflated models exhibit a better fit than the zero-inflated Poisson and standard Poisson regressions. Copyright © 2012 John Wiley & Sons, Ltd.

Analyzing Propensity Matched Zero-Inflated Count Outcomes in Observational Studies

PubMed Central

DeSantis, Stacia M.; Lazaridis, Christos; Ji, Shuang; Spinale, Francis G.

2013-01-01

Determining the effectiveness of different treatments from observational data, which are characterized by imbalance between groups due to lack of randomization, is challenging. Propensity matching is often used to rectify imbalances among prognostic variables. However, there are no guidelines on how appropriately to analyze group matched data when the outcome is a zero inflated count. In addition, there is debate over whether to account for correlation of responses induced by matching, and/or whether to adjust for variables used in generating the propensity score in the final analysis. The aim of this research is to compare covariate unadjusted and adjusted zero-inflated Poisson models that do and do not account for the correlation. A simulation study is conducted, demonstrating that it is necessary to adjust for potential residual confounding, but that accounting for correlation is less important. The methods are applied to a biomedical research data set. PMID:24298197

Spatiotemporal hurdle models for zero-inflated count data: Exploring trends in emergency department visits.

PubMed

Neelon, Brian; Chang, Howard H; Ling, Qiang; Hastings, Nicole S

2016-12-01

Motivated by a study exploring spatiotemporal trends in emergency department use, we develop a class of two-part hurdle models for the analysis of zero-inflated areal count data. The models consist of two components-one for the probability of any emergency department use and one for the number of emergency department visits given use. Through a hierarchical structure, the models incorporate both patient- and region-level predictors, as well as spatially and temporally correlated random effects for each model component. The random effects are assigned multivariate conditionally autoregressive priors, which induce dependence between the components and provide spatial and temporal smoothing across adjacent spatial units and time periods, resulting in improved inferences. To accommodate potential overdispersion, we consider a range of parametric specifications for the positive counts, including truncated negative binomial and generalized Poisson distributions. We adopt a Bayesian inferential approach, and posterior computation is handled conveniently within standard Bayesian software. Our results indicate that the negative binomial and generalized Poisson hurdle models vastly outperform the Poisson hurdle model, demonstrating that overdispersed hurdle models provide a useful approach to analyzing zero-inflated spatiotemporal data. © The Author(s) 2014.

A comparison of different statistical methods analyzing hypoglycemia data using bootstrap simulations.

PubMed

Jiang, Honghua; Ni, Xiao; Huster, William; Heilmann, Cory

2015-01-01

Hypoglycemia has long been recognized as a major barrier to achieving normoglycemia with intensive diabetic therapies. It is a common safety concern for the diabetes patients. Therefore, it is important to apply appropriate statistical methods when analyzing hypoglycemia data. Here, we carried out bootstrap simulations to investigate the performance of the four commonly used statistical models (Poisson, negative binomial, analysis of covariance [ANCOVA], and rank ANCOVA) based on the data from a diabetes clinical trial. Zero-inflated Poisson (ZIP) model and zero-inflated negative binomial (ZINB) model were also evaluated. Simulation results showed that Poisson model inflated type I error, while negative binomial model was overly conservative. However, after adjusting for dispersion, both Poisson and negative binomial models yielded slightly inflated type I errors, which were close to the nominal level and reasonable power. Reasonable control of type I error was associated with ANCOVA model. Rank ANCOVA model was associated with the greatest power and with reasonable control of type I error. Inflated type I error was observed with ZIP and ZINB models.

Marginalized multilevel hurdle and zero-inflated models for overdispersed and correlated count data with excess zeros.

PubMed

Kassahun, Wondwosen; Neyens, Thomas; Molenberghs, Geert; Faes, Christel; Verbeke, Geert

2014-11-10

Count data are collected repeatedly over time in many applications, such as biology, epidemiology, and public health. Such data are often characterized by the following three features. First, correlation due to the repeated measures is usually accounted for using subject-specific random effects, which are assumed to be normally distributed. Second, the sample variance may exceed the mean, and hence, the theoretical mean-variance relationship is violated, leading to overdispersion. This is usually allowed for based on a hierarchical approach, combining a Poisson model with gamma distributed random effects. Third, an excess of zeros beyond what standard count distributions can predict is often handled by either the hurdle or the zero-inflated model. A zero-inflated model assumes two processes as sources of zeros and combines a count distribution with a discrete point mass as a mixture, while the hurdle model separately handles zero observations and positive counts, where then a truncated-at-zero count distribution is used for the non-zero state. In practice, however, all these three features can appear simultaneously. Hence, a modeling framework that incorporates all three is necessary, and this presents challenges for the data analysis. Such models, when conditionally specified, will naturally have a subject-specific interpretation. However, adopting their purposefully modified marginalized versions leads to a direct marginal or population-averaged interpretation for parameter estimates of covariate effects, which is the primary interest in many applications. In this paper, we present a marginalized hurdle model and a marginalized zero-inflated model for correlated and overdispersed count data with excess zero observations and then illustrate these further with two case studies. The first dataset focuses on the Anopheles mosquito density around a hydroelectric dam, while adolescents' involvement in work, to earn money and support their families or themselves, is

Zero-inflated spatio-temporal models for disease mapping.

PubMed

Torabi, Mahmoud

2017-05-01

In this paper, our aim is to analyze geographical and temporal variability of disease incidence when spatio-temporal count data have excess zeros. To that end, we consider random effects in zero-inflated Poisson models to investigate geographical and temporal patterns of disease incidence. Spatio-temporal models that employ conditionally autoregressive smoothing across the spatial dimension and B-spline smoothing over the temporal dimension are proposed. The analysis of these complex models is computationally difficult from the frequentist perspective. On the other hand, the advent of the Markov chain Monte Carlo algorithm has made the Bayesian analysis of complex models computationally convenient. Recently developed data cloning method provides a frequentist approach to mixed models that is also computationally convenient. We propose to use data cloning, which yields to maximum likelihood estimation, to conduct frequentist analysis of zero-inflated spatio-temporal modeling of disease incidence. One of the advantages of the data cloning approach is that the prediction and corresponding standard errors (or prediction intervals) of smoothing disease incidence over space and time is easily obtained. We illustrate our approach using a real dataset of monthly children asthma visits to hospital in the province of Manitoba, Canada, during the period April 2006 to March 2010. Performance of our approach is also evaluated through a simulation study. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Review and Recommendations for Zero-inflated Count Regression Modeling of Dental Caries Indices in Epidemiological Studies

PubMed Central

Stamm, John W.; Long, D. Leann; Kincade, Megan E.

2012-01-01

Over the past five to ten years, zero-inflated count regression models have been increasingly applied to the analysis of dental caries indices (e.g., DMFT, dfms, etc). The main reason for that is linked to the broad decline in children’s caries experience, such that dmf and DMF indices more frequently generate low or even zero counts. This article specifically reviews the application of zero-inflated Poisson and zero-inflated negative binomial regression models to dental caries, with emphasis on the description of the models and the interpretation of fitted model results given the study goals. The review finds that interpretations provided in the published caries research are often imprecise or inadvertently misleading, particularly with respect to failing to discriminate between inference for the class of susceptible persons defined by such models and inference for the sampled population in terms of overall exposure effects. Recommendations are provided to enhance the use as well as the interpretation and reporting of results of count regression models when applied to epidemiological studies of dental caries. PMID:22710271

A new approach for handling longitudinal count data with zero-inflation and overdispersion: poisson geometric process model.

PubMed

Wan, Wai-Yin; Chan, Jennifer S K

2009-08-01

For time series of count data, correlated measurements, clustering as well as excessive zeros occur simultaneously in biomedical applications. Ignoring such effects might contribute to misleading treatment outcomes. A generalized mixture Poisson geometric process (GMPGP) model and a zero-altered mixture Poisson geometric process (ZMPGP) model are developed from the geometric process model, which was originally developed for modelling positive continuous data and was extended to handle count data. These models are motivated by evaluating the trend development of new tumour counts for bladder cancer patients as well as by identifying useful covariates which affect the count level. The models are implemented using Bayesian method with Markov chain Monte Carlo (MCMC) algorithms and are assessed using deviance information criterion (DIC).

A Three-dimensional Polymer Scaffolding Material Exhibiting a Zero Poisson's Ratio.

PubMed

Soman, Pranav; Fozdar, David Y; Lee, Jin Woo; Phadke, Ameya; Varghese, Shyni; Chen, Shaochen

2012-05-14

Poisson's ratio describes the degree to which a material contracts (expands) transversally when axially strained. A material with a zero Poisson's ratio does not transversally deform in response to an axial strain (stretching). In tissue engineering applications, scaffolding having a zero Poisson's ratio (ZPR) may be more suitable for emulating the behavior of native tissues and accommodating and transmitting forces to the host tissue site during wound healing (or tissue regrowth). For example, scaffolding with a zero Poisson's ratio may be beneficial in the engineering of cartilage, ligament, corneal, and brain tissues, which are known to possess Poisson's ratios of nearly zero. Here, we report a 3D biomaterial constructed from polyethylene glycol (PEG) exhibiting in-plane Poisson's ratios of zero for large values of axial strain. We use digital micro-mirror device projection printing (DMD-PP) to create single- and double-layer scaffolds composed of semi re-entrant pores whose arrangement and deformation mechanisms contribute the zero Poisson's ratio. Strain experiments prove the zero Poisson's behavior of the scaffolds and that the addition of layers does not change the Poisson's ratio. Human mesenchymal stem cells (hMSCs) cultured on biomaterials with zero Poisson's ratio demonstrate the feasibility of utilizing these novel materials for biological applications which require little to no transverse deformations resulting from axial strains. Techniques used in this work allow Poisson's ratio to be both scale-independent and independent of the choice of strut material for strains in the elastic regime, and therefore ZPR behavior can be imparted to a variety of photocurable biomaterial.

Zero adjusted models with applications to analysing helminths count data.

PubMed

Chipeta, Michael G; Ngwira, Bagrey M; Simoonga, Christopher; Kazembe, Lawrence N

2014-11-27

It is common in public health and epidemiology that the outcome of interest is counts of events occurrence. Analysing these data using classical linear models is mostly inappropriate, even after transformation of outcome variables due to overdispersion. Zero-adjusted mixture count models such as zero-inflated and hurdle count models are applied to count data when over-dispersion and excess zeros exist. Main objective of the current paper is to apply such models to analyse risk factors associated with human helminths (S. haematobium) particularly in a case where there's a high proportion of zero counts. The data were collected during a community-based randomised control trial assessing the impact of mass drug administration (MDA) with praziquantel in Malawi, and a school-based cross sectional epidemiology survey in Zambia. Count data models including traditional (Poisson and negative binomial) models, zero modified models (zero inflated Poisson and zero inflated negative binomial) and hurdle models (Poisson logit hurdle and negative binomial logit hurdle) were fitted and compared. Using Akaike information criteria (AIC), the negative binomial logit hurdle (NBLH) and zero inflated negative binomial (ZINB) showed best performance in both datasets. With regards to zero count capturing, these models performed better than other models. This paper showed that zero modified NBLH and ZINB models are more appropriate methods for the analysis of data with excess zeros. The choice between the hurdle and zero-inflated models should be based on the aim and endpoints of the study.

A time-varying effect model for examining group differences in trajectories of zero-inflated count outcomes with applications in substance abuse research.

PubMed

Yang, Songshan; Cranford, James A; Jester, Jennifer M; Li, Runze; Zucker, Robert A; Buu, Anne

2017-02-28

This study proposes a time-varying effect model for examining group differences in trajectories of zero-inflated count outcomes. The motivating example demonstrates that this zero-inflated Poisson model allows investigators to study group differences in different aspects of substance use (e.g., the probability of abstinence and the quantity of alcohol use) simultaneously. The simulation study shows that the accuracy of estimation of trajectory functions improves as the sample size increases; the accuracy under equal group sizes is only higher when the sample size is small (100). In terms of the performance of the hypothesis testing, the type I error rates are close to their corresponding significance levels under all settings. Furthermore, the power increases as the alternative hypothesis deviates more from the null hypothesis, and the rate of this increasing trend is higher when the sample size is larger. Moreover, the hypothesis test for the group difference in the zero component tends to be less powerful than the test for the group difference in the Poisson component. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Assessment and Selection of Competing Models for Zero-Inflated Microbiome Data

PubMed Central

Xu, Lizhen; Paterson, Andrew D.; Turpin, Williams; Xu, Wei

2015-01-01

Typical data in a microbiome study consist of the operational taxonomic unit (OTU) counts that have the characteristic of excess zeros, which are often ignored by investigators. In this paper, we compare the performance of different competing methods to model data with zero inflated features through extensive simulations and application to a microbiome study. These methods include standard parametric and non-parametric models, hurdle models, and zero inflated models. We examine varying degrees of zero inflation, with or without dispersion in the count component, as well as different magnitude and direction of the covariate effect on structural zeros and the count components. We focus on the assessment of type I error, power to detect the overall covariate effect, measures of model fit, and bias and effectiveness of parameter estimations. We also evaluate the abilities of model selection strategies using Akaike information criterion (AIC) or Vuong test to identify the correct model. The simulation studies show that hurdle and zero inflated models have well controlled type I errors, higher power, better goodness of fit measures, and are more accurate and efficient in the parameter estimation. Besides that, the hurdle models have similar goodness of fit and parameter estimation for the count component as their corresponding zero inflated models. However, the estimation and interpretation of the parameters for the zero components differs, and hurdle models are more stable when structural zeros are absent. We then discuss the model selection strategy for zero inflated data and implement it in a gut microbiome study of > 400 independent subjects. PMID:26148172

Assessment and Selection of Competing Models for Zero-Inflated Microbiome Data.

PubMed

Xu, Lizhen; Paterson, Andrew D; Turpin, Williams; Xu, Wei

2015-01-01

Typical data in a microbiome study consist of the operational taxonomic unit (OTU) counts that have the characteristic of excess zeros, which are often ignored by investigators. In this paper, we compare the performance of different competing methods to model data with zero inflated features through extensive simulations and application to a microbiome study. These methods include standard parametric and non-parametric models, hurdle models, and zero inflated models. We examine varying degrees of zero inflation, with or without dispersion in the count component, as well as different magnitude and direction of the covariate effect on structural zeros and the count components. We focus on the assessment of type I error, power to detect the overall covariate effect, measures of model fit, and bias and effectiveness of parameter estimations. We also evaluate the abilities of model selection strategies using Akaike information criterion (AIC) or Vuong test to identify the correct model. The simulation studies show that hurdle and zero inflated models have well controlled type I errors, higher power, better goodness of fit measures, and are more accurate and efficient in the parameter estimation. Besides that, the hurdle models have similar goodness of fit and parameter estimation for the count component as their corresponding zero inflated models. However, the estimation and interpretation of the parameters for the zero components differs, and hurdle models are more stable when structural zeros are absent. We then discuss the model selection strategy for zero inflated data and implement it in a gut microbiome study of > 400 independent subjects.

A review on models for count data with extra zeros

NASA Astrophysics Data System (ADS)

Zamri, Nik Sarah Nik; Zamzuri, Zamira Hasanah

2017-04-01

Typically, the zero inflated models are usually used in modelling count data with excess zeros. The existence of the extra zeros could be structural zeros or random which occur by chance. These types of data are commonly found in various disciplines such as finance, insurance, biomedical, econometrical, ecology, and health sciences. As found in the literature, the most popular zero inflated models used are zero inflated Poisson and zero inflated negative binomial. Recently, more complex models have been developed to account for overdispersion and unobserved heterogeneity. In addition, more extended distributions are also considered in modelling data with this feature. In this paper, we review related literature, provide a recent development and summary on models for count data with extra zeros.

Statistical Models for the Analysis of Zero-Inflated Pain Intensity Numeric Rating Scale Data.

PubMed

Goulet, Joseph L; Buta, Eugenia; Bathulapalli, Harini; Gueorguieva, Ralitza; Brandt, Cynthia A

2017-03-01

Pain intensity is often measured in clinical and research settings using the 0 to 10 numeric rating scale (NRS). NRS scores are recorded as discrete values, and in some samples they may display a high proportion of zeroes and a right-skewed distribution. Despite this, statistical methods for normally distributed data are frequently used in the analysis of NRS data. We present results from an observational cross-sectional study examining the association of NRS scores with patient characteristics using data collected from a large cohort of 18,935 veterans in Department of Veterans Affairs care diagnosed with a potentially painful musculoskeletal disorder. The mean (variance) NRS pain was 3.0 (7.5), and 34% of patients reported no pain (NRS = 0). We compared the following statistical models for analyzing NRS scores: linear regression, generalized linear models (Poisson and negative binomial), zero-inflated and hurdle models for data with an excess of zeroes, and a cumulative logit model for ordinal data. We examined model fit, interpretability of results, and whether conclusions about the predictor effects changed across models. In this study, models that accommodate zero inflation provided a better fit than the other models. These models should be considered for the analysis of NRS data with a large proportion of zeroes. We examined and analyzed pain data from a large cohort of veterans with musculoskeletal disorders. We found that many reported no current pain on the NRS on the diagnosis date. We present several alternative statistical methods for the analysis of pain intensity data with a large proportion of zeroes. Published by Elsevier Inc.

Marginalized zero-altered models for longitudinal count data.

PubMed

Tabb, Loni Philip; Tchetgen, Eric J Tchetgen; Wellenius, Greg A; Coull, Brent A

2016-10-01

Count data often exhibit more zeros than predicted by common count distributions like the Poisson or negative binomial. In recent years, there has been considerable interest in methods for analyzing zero-inflated count data in longitudinal or other correlated data settings. A common approach has been to extend zero-inflated Poisson models to include random effects that account for correlation among observations. However, these models have been shown to have a few drawbacks, including interpretability of regression coefficients and numerical instability of fitting algorithms even when the data arise from the assumed model. To address these issues, we propose a model that parameterizes the marginal associations between the count outcome and the covariates as easily interpretable log relative rates, while including random effects to account for correlation among observations. One of the main advantages of this marginal model is that it allows a basis upon which we can directly compare the performance of standard methods that ignore zero inflation with that of a method that explicitly takes zero inflation into account. We present simulations of these various model formulations in terms of bias and variance estimation. Finally, we apply the proposed approach to analyze toxicological data of the effect of emissions on cardiac arrhythmias.

Marginalized zero-altered models for longitudinal count data

PubMed Central

Tabb, Loni Philip; Tchetgen, Eric J. Tchetgen; Wellenius, Greg A.; Coull, Brent A.

2015-01-01

Count data often exhibit more zeros than predicted by common count distributions like the Poisson or negative binomial. In recent years, there has been considerable interest in methods for analyzing zero-inflated count data in longitudinal or other correlated data settings. A common approach has been to extend zero-inflated Poisson models to include random effects that account for correlation among observations. However, these models have been shown to have a few drawbacks, including interpretability of regression coefficients and numerical instability of fitting algorithms even when the data arise from the assumed model. To address these issues, we propose a model that parameterizes the marginal associations between the count outcome and the covariates as easily interpretable log relative rates, while including random effects to account for correlation among observations. One of the main advantages of this marginal model is that it allows a basis upon which we can directly compare the performance of standard methods that ignore zero inflation with that of a method that explicitly takes zero inflation into account. We present simulations of these various model formulations in terms of bias and variance estimation. Finally, we apply the proposed approach to analyze toxicological data of the effect of emissions on cardiac arrhythmias. PMID:27867423

Item Response Modeling of Multivariate Count Data with Zero Inflation, Maximum Inflation, and Heaping

ERIC Educational Resources Information Center

Magnus, Brooke E.; Thissen, David

2017-01-01

Questionnaires that include items eliciting count responses are becoming increasingly common in psychology. This study proposes methodological techniques to overcome some of the challenges associated with analyzing multivariate item response data that exhibit zero inflation, maximum inflation, and heaping at preferred digits. The modeling…

Observation weights unlock bulk RNA-seq tools for zero inflation and single-cell applications.

PubMed

Van den Berge, Koen; Perraudeau, Fanny; Soneson, Charlotte; Love, Michael I; Risso, Davide; Vert, Jean-Philippe; Robinson, Mark D; Dudoit, Sandrine; Clement, Lieven

2018-02-26

Dropout events in single-cell RNA sequencing (scRNA-seq) cause many transcripts to go undetected and induce an excess of zero read counts, leading to power issues in differential expression (DE) analysis. This has triggered the development of bespoke scRNA-seq DE methods to cope with zero inflation. Recent evaluations, however, have shown that dedicated scRNA-seq tools provide no advantage compared to traditional bulk RNA-seq tools. We introduce a weighting strategy, based on a zero-inflated negative binomial model, that identifies excess zero counts and generates gene- and cell-specific weights to unlock bulk RNA-seq DE pipelines for zero-inflated data, boosting performance for scRNA-seq.

SEMIPARAMETRIC ZERO-INFLATED MODELING IN MULTI-ETHNIC STUDY OF ATHEROSCLEROSIS (MESA)

PubMed Central

Liu, Hai; Ma, Shuangge; Kronmal, Richard; Chan, Kung-Sik

2013-01-01

We analyze the Agatston score of coronary artery calcium (CAC) from the Multi-Ethnic Study of Atherosclerosis (MESA) using semi-parametric zero-inflated modeling approach, where the observed CAC scores from this cohort consist of high frequency of zeroes and continuously distributed positive values. Both partially constrained and unconstrained models are considered to investigate the underlying biological processes of CAC development from zero to positive, and from small amount to large amount. Different from existing studies, a model selection procedure based on likelihood cross-validation is adopted to identify the optimal model, which is justified by comparative Monte Carlo studies. A shrinkaged version of cubic regression spline is used for model estimation and variable selection simultaneously. When applying the proposed methods to the MESA data analysis, we show that the two biological mechanisms influencing the initiation of CAC and the magnitude of CAC when it is positive are better characterized by an unconstrained zero-inflated normal model. Our results are significantly different from those in published studies, and may provide further insights into the biological mechanisms underlying CAC development in human. This highly flexible statistical framework can be applied to zero-inflated data analyses in other areas. PMID:23805172

Empirical null estimation using zero-inflated discrete mixture distributions and its application to protein domain data.

PubMed

Gauran, Iris Ivy M; Park, Junyong; Lim, Johan; Park, DoHwan; Zylstra, John; Peterson, Thomas; Kann, Maricel; Spouge, John L

2017-09-22

In recent mutation studies, analyses based on protein domain positions are gaining popularity over gene-centric approaches since the latter have limitations in considering the functional context that the position of the mutation provides. This presents a large-scale simultaneous inference problem, with hundreds of hypothesis tests to consider at the same time. This article aims to select significant mutation counts while controlling a given level of Type I error via False Discovery Rate (FDR) procedures. One main assumption is that the mutation counts follow a zero-inflated model in order to account for the true zeros in the count model and the excess zeros. The class of models considered is the Zero-inflated Generalized Poisson (ZIGP) distribution. Furthermore, we assumed that there exists a cut-off value such that smaller counts than this value are generated from the null distribution. We present several data-dependent methods to determine the cut-off value. We also consider a two-stage procedure based on screening process so that the number of mutations exceeding a certain value should be considered as significant mutations. Simulated and protein domain data sets are used to illustrate this procedure in estimation of the empirical null using a mixture of discrete distributions. Overall, while maintaining control of the FDR, the proposed two-stage testing procedure has superior empirical power. 2017 The Authors. Biometrics published by Wiley Periodicals, Inc. on behalf of International Biometric Society This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Poisson Mixture Regression Models for Heart Disease Prediction.

PubMed

Mufudza, Chipo; Erol, Hamza

2016-01-01

Early heart disease control can be achieved by high disease prediction and diagnosis efficiency. This paper focuses on the use of model based clustering techniques to predict and diagnose heart disease via Poisson mixture regression models. Analysis and application of Poisson mixture regression models is here addressed under two different classes: standard and concomitant variable mixture regression models. Results show that a two-component concomitant variable Poisson mixture regression model predicts heart disease better than both the standard Poisson mixture regression model and the ordinary general linear Poisson regression model due to its low Bayesian Information Criteria value. Furthermore, a Zero Inflated Poisson Mixture Regression model turned out to be the best model for heart prediction over all models as it both clusters individuals into high or low risk category and predicts rate to heart disease componentwise given clusters available. It is deduced that heart disease prediction can be effectively done by identifying the major risks componentwise using Poisson mixture regression model.

Poisson Mixture Regression Models for Heart Disease Prediction

PubMed Central

Erol, Hamza

2016-01-01

Early heart disease control can be achieved by high disease prediction and diagnosis efficiency. This paper focuses on the use of model based clustering techniques to predict and diagnose heart disease via Poisson mixture regression models. Analysis and application of Poisson mixture regression models is here addressed under two different classes: standard and concomitant variable mixture regression models. Results show that a two-component concomitant variable Poisson mixture regression model predicts heart disease better than both the standard Poisson mixture regression model and the ordinary general linear Poisson regression model due to its low Bayesian Information Criteria value. Furthermore, a Zero Inflated Poisson Mixture Regression model turned out to be the best model for heart prediction over all models as it both clusters individuals into high or low risk category and predicts rate to heart disease componentwise given clusters available. It is deduced that heart disease prediction can be effectively done by identifying the major risks componentwise using Poisson mixture regression model. PMID:27999611

Zero-state Markov switching count-data models: an empirical assessment.

PubMed

Malyshkina, Nataliya V; Mannering, Fred L

2010-01-01

In this study, a two-state Markov switching count-data model is proposed as an alternative to zero-inflated models to account for the preponderance of zeros sometimes observed in transportation count data, such as the number of accidents occurring on a roadway segment over some period of time. For this accident-frequency case, zero-inflated models assume the existence of two states: one of the states is a zero-accident count state, which has accident probabilities that are so low that they cannot be statistically distinguished from zero, and the other state is a normal-count state, in which counts can be non-negative integers that are generated by some counting process, for example, a Poisson or negative binomial. While zero-inflated models have come under some criticism with regard to accident-frequency applications - one fact is undeniable - in many applications they provide a statistically superior fit to the data. The Markov switching approach we propose seeks to overcome some of the criticism associated with the zero-accident state of the zero-inflated model by allowing individual roadway segments to switch between zero and normal-count states over time. An important advantage of this Markov switching approach is that it allows for the direct statistical estimation of the specific roadway-segment state (i.e., zero-accident or normal-count state) whereas traditional zero-inflated models do not. To demonstrate the applicability of this approach, a two-state Markov switching negative binomial model (estimated with Bayesian inference) and standard zero-inflated negative binomial models are estimated using five-year accident frequencies on Indiana interstate highway segments. It is shown that the Markov switching model is a viable alternative and results in a superior statistical fit relative to the zero-inflated models.

Poisson's ratio from polarization of acoustic zero-group velocity Lamb mode.

PubMed

Baggens, Oskar; Ryden, Nils

2015-07-01

Poisson's ratio of an isotropic and free elastic plate is estimated from the polarization of the first symmetric acoustic zero-group velocity Lamb mode. This polarization is interpreted as the ratio of the absolute amplitudes of the surface normal and surface in-plane components of the acoustic mode. Results from the evaluation of simulated datasets indicate that the presented relation, which links the polarization and Poisson's ratio, can be extended to incorporate plates with material damping. Furthermore, the proposed application of the polarization is demonstrated in a practical field case, where an increased accuracy of estimated nominal thickness is obtained.

Zero-Inflated Models for Identifying Relationships Between Body Mass Index and Gastroesophageal Reflux Symptoms: A Nationwide Population-Based Study in China.

PubMed

Xu, Qin; Zhang, Wei; Zhang, Tianyi; Zhang, Ruijie; Zhao, Yanfang; Zhang, Yuan; Guo, Yibin; Wang, Rui; Ma, Xiuqiang; He, Jia

2016-07-01

That obesity leads to gastroesophageal reflux is a widespread notion. However, scientific evidence for this association is limited, with no rigorous epidemiological approach conducted to address this question. This study examined the relationship between body mass index (BMI) and gastroesophageal reflux symptoms in a large population-representative sample from China. We performed a cross-sectional study in an age- and gender-stratified random sample of the population of five central regions in China. Participants aged 18-80 years completed a general information questionnaire and a Chinese version of the Reflux Disease Questionnaire. The zero-inflated Poisson regression model estimated the relationship between body mass index and gastroesophageal reflux symptoms. Overall, 16,091 (89.4 %) of the 18,000 eligible participants responded. 638 (3.97 %) and 1738 (10.81 %) experienced at least weekly heartburn and weekly acid regurgitation, respectively. After adjusting for potential risk factors in the zero-inflated part, the frequency [odds ratio (OR) 0.66, 95 % confidence interval (95 % CI) 0.50-0.86, p = 0.002] and severity (OR 0.66, 95 % CI 0.50-088, p = 0.004) of heartburn in obese participants were statistically significant compared to those in normal participants. In the Poisson part, the frequency of acid regurgitation, overweight (OR 1.10, 95 % CI 1.01-1.21, p = 0.038) and obesity (OR 1.19, 95 % CI 1.04-1.37, p = 0.013) were statistically significant. BMI was strongly and positively related to the frequency and severity of gastroesophageal reflux symptoms. Additionally, gender exerted strong specific effects on the relationship between BMI and gastroesophageal reflux symptoms. The severity and frequency of heartburn were positively correlated with obesity. This relationship was presented distinct in male participants only.

Identifiability in N-mixture models: a large-scale screening test with bird data.

PubMed

Kéry, Marc

2018-02-01

Binomial N-mixture models have proven very useful in ecology, conservation, and monitoring: they allow estimation and modeling of abundance separately from detection probability using simple counts. Recently, doubts about parameter identifiability have been voiced. I conducted a large-scale screening test with 137 bird data sets from 2,037 sites. I found virtually no identifiability problems for Poisson and zero-inflated Poisson (ZIP) binomial N-mixture models, but negative-binomial (NB) models had problems in 25% of all data sets. The corresponding multinomial N-mixture models had no problems. Parameter estimates under Poisson and ZIP binomial and multinomial N-mixture models were extremely similar. Identifiability problems became a little more frequent with smaller sample sizes (267 and 50 sites), but were unaffected by whether the models did or did not include covariates. Hence, binomial N-mixture model parameters with Poisson and ZIP mixtures typically appeared identifiable. In contrast, NB mixtures were often unidentifiable, which is worrying since these were often selected by Akaike's information criterion. Identifiability of binomial N-mixture models should always be checked. If problems are found, simpler models, integrated models that combine different observation models or the use of external information via informative priors or penalized likelihoods, may help. © 2017 by the Ecological Society of America.

Comparing statistical methods for analyzing skewed longitudinal count data with many zeros: an example of smoking cessation.

PubMed

Xie, Haiyi; Tao, Jill; McHugo, Gregory J; Drake, Robert E

2013-07-01

Count data with skewness and many zeros are common in substance abuse and addiction research. Zero-adjusting models, especially zero-inflated models, have become increasingly popular in analyzing this type of data. This paper reviews and compares five mixed-effects Poisson family models commonly used to analyze count data with a high proportion of zeros by analyzing a longitudinal outcome: number of smoking quit attempts from the New Hampshire Dual Disorders Study. The findings of our study indicated that count data with many zeros do not necessarily require zero-inflated or other zero-adjusting models. For rare event counts or count data with small means, a simpler model such as the negative binomial model may provide a better fit. Copyright © 2013 Elsevier Inc. All rights reserved.

Trending in Probability of Collision Measurements via a Bayesian Zero-Inflated Beta Mixed Model

NASA Technical Reports Server (NTRS)

Vallejo, Jonathon; Hejduk, Matt; Stamey, James

2015-01-01

We investigate the performance of a generalized linear mixed model in predicting the Probabilities of Collision (Pc) for conjunction events. Specifically, we apply this model to the log(sub 10) transformation of these probabilities and argue that this transformation yields values that can be considered bounded in practice. Additionally, this bounded random variable, after scaling, is zero-inflated. Consequently, we model these values using the zero-inflated Beta distribution, and utilize the Bayesian paradigm and the mixed model framework to borrow information from past and current events. This provides a natural way to model the data and provides a basis for answering questions of interest, such as what is the likelihood of observing a probability of collision equal to the effective value of zero on a subsequent observation.

A Zero- and K-Inflated Mixture Model for Health Questionnaire Data

PubMed Central

Finkelman, Matthew D.; Green, Jennifer Greif; Gruber, Michael J.; Zaslavsky, Alan M.

2011-01-01

In psychiatric assessment, Item Response Theory (IRT) is a popular tool to formalize the relation between the severity of a disorder and associated responses to questionnaire items. Practitioners of IRT sometimes make the assumption of normally distributed severities within a population; while convenient, this assumption is often violated when measuring psychiatric disorders. Specifically, there may be a sizable group of respondents whose answers place them at an extreme of the latent trait spectrum. In this article, a zero- and K-inflated mixture model is developed to account for the presence of such respondents. The model is fitted using an expectation-maximization (E-M) algorithm to estimate the percentage of the population at each end of the continuum, concurrently analyzing the remaining “graded component” via IRT. A method to perform factor analysis for only the graded component is introduced. In assessments of oppositional defiant disorder and conduct disorder, the zero- and K-inflated model exhibited better fit than the standard IRT model. PMID:21365673

Disease Mapping of Zero-excessive Mesothelioma Data in Flanders

PubMed Central

Neyens, Thomas; Lawson, Andrew B.; Kirby, Russell S.; Nuyts, Valerie; Watjou, Kevin; Aregay, Mehreteab; Carroll, Rachel; Nawrot, Tim S.; Faes, Christel

2016-01-01

Purpose To investigate the distribution of mesothelioma in Flanders using Bayesian disease mapping models that account for both an excess of zeros and overdispersion. Methods The numbers of newly diagnosed mesothelioma cases within all Flemish municipalities between 1999 and 2008 were obtained from the Belgian Cancer Registry. To deal with overdispersion, zero-inflation and geographical association, the hurdle combined model was proposed, which has three components: a Bernoulli zero-inflation mixture component to account for excess zeros, a gamma random effect to adjust for overdispersion and a normal conditional autoregressive random effect to attribute spatial association. This model was compared with other existing methods in literature. Results The results indicate that hurdle models with a random effects term accounting for extra-variance in the Bernoulli zero-inflation component fit the data better than hurdle models that do not take overdispersion in the occurrence of zeros into account. Furthermore, traditional models that do not take into account excessive zeros but contain at least one random effects term that models extra-variance in the counts have better fits compared to their hurdle counterparts. In other words, the extra-variability, due to an excess of zeros, can be accommodated by spatially structured and/or unstructured random effects in a Poisson model such that the hurdle mixture model is not necessary. Conclusions Models taking into account zero-inflation do not always provide better fits to data with excessive zeros than less complex models. In this study, a simple conditional autoregressive model identified a cluster in mesothelioma cases near a former asbestos processing plant (Kapelle-op-den-Bos). This observation is likely linked with historical local asbestos exposures. Future research will clarify this. PMID:27908590

Disease mapping of zero-excessive mesothelioma data in Flanders.

PubMed

Neyens, Thomas; Lawson, Andrew B; Kirby, Russell S; Nuyts, Valerie; Watjou, Kevin; Aregay, Mehreteab; Carroll, Rachel; Nawrot, Tim S; Faes, Christel

2017-01-01

To investigate the distribution of mesothelioma in Flanders using Bayesian disease mapping models that account for both an excess of zeros and overdispersion. The numbers of newly diagnosed mesothelioma cases within all Flemish municipalities between 1999 and 2008 were obtained from the Belgian Cancer Registry. To deal with overdispersion, zero inflation, and geographical association, the hurdle combined model was proposed, which has three components: a Bernoulli zero-inflation mixture component to account for excess zeros, a gamma random effect to adjust for overdispersion, and a normal conditional autoregressive random effect to attribute spatial association. This model was compared with other existing methods in literature. The results indicate that hurdle models with a random effects term accounting for extra variance in the Bernoulli zero-inflation component fit the data better than hurdle models that do not take overdispersion in the occurrence of zeros into account. Furthermore, traditional models that do not take into account excessive zeros but contain at least one random effects term that models extra variance in the counts have better fits compared to their hurdle counterparts. In other words, the extra variability, due to an excess of zeros, can be accommodated by spatially structured and/or unstructured random effects in a Poisson model such that the hurdle mixture model is not necessary. Models taking into account zero inflation do not always provide better fits to data with excessive zeros than less complex models. In this study, a simple conditional autoregressive model identified a cluster in mesothelioma cases near a former asbestos processing plant (Kapelle-op-den-Bos). This observation is likely linked with historical local asbestos exposures. Future research will clarify this. Copyright © 2016 Elsevier Inc. All rights reserved.

GMPR: A robust normalization method for zero-inflated count data with application to microbiome sequencing data.

PubMed

Chen, Li; Reeve, James; Zhang, Lujun; Huang, Shengbing; Wang, Xuefeng; Chen, Jun

2018-01-01

Normalization is the first critical step in microbiome sequencing data analysis used to account for variable library sizes. Current RNA-Seq based normalization methods that have been adapted for microbiome data fail to consider the unique characteristics of microbiome data, which contain a vast number of zeros due to the physical absence or under-sampling of the microbes. Normalization methods that specifically address the zero-inflation remain largely undeveloped. Here we propose geometric mean of pairwise ratios-a simple but effective normalization method-for zero-inflated sequencing data such as microbiome data. Simulation studies and real datasets analyses demonstrate that the proposed method is more robust than competing methods, leading to more powerful detection of differentially abundant taxa and higher reproducibility of the relative abundances of taxa.

Modeling Associations between Principals' Reported Indoor Environmental Quality and Students' Self-Reported Respiratory Health Outcomes Using GLMM and ZIP Models.

PubMed

Toyinbo, Oluyemi; Matilainen, Markus; Turunen, Mari; Putus, Tuula; Shaughnessy, Richard; Haverinen-Shaughnessy, Ulla

2016-03-30

The aim of this paper was to examine associations between school building characteristics, indoor environmental quality (IEQ), and health responses using questionnaire data from both school principals and students. From 334 randomly sampled schools, 4248 sixth grade students from 297 schools participated in a questionnaire. From these schools, 134 principals returned questionnaires concerning 51 IEQ related questions of their school. Generalized linear mixed models (GLMM) were used to study the associations between IEQ indicators and existence of self-reported upper respiratory symptoms, while hierarchical Zero Inflated Poisson (ZIP)-models were used to model the number of symptoms. Significant associations were established between existence of upper respiratory symptoms and unsatisfactory classroom temperature during the heating season (ORs 1.45 for too hot and cold, and 1.27 for too cold as compared to satisfactory temperature) and dampness or moisture damage during the year 2006-2007 (OR: 1.80 as compared to no moisture damage), respectively. The number of upper respiratory symptoms was significantly associated with inadequate ventilation and dampness or moisture damage. A higher number of missed school days due to respiratory infections were reported in schools with inadequate ventilation (RR: 1.16). The school level IEQ indicator variables described in this paper could explain a relatively large part of the school level variation observed in the self-reported upper respiratory symptoms and missed school days due to respiratory infections among students.

Three-dimensionally bonded spongy graphene material with super compressive elasticity and near-zero Poisson's ratio.

PubMed

Wu, Yingpeng; Yi, Ningbo; Huang, Lu; Zhang, Tengfei; Fang, Shaoli; Chang, Huicong; Li, Na; Oh, Jiyoung; Lee, Jae Ah; Kozlov, Mikhail; Chipara, Alin C; Terrones, Humberto; Xiao, Peishuang; Long, Guankui; Huang, Yi; Zhang, Fan; Zhang, Long; Lepró, Xavier; Haines, Carter; Lima, Márcio Dias; Lopez, Nestor Perea; Rajukumar, Lakshmy P; Elias, Ana L; Feng, Simin; Kim, Seon Jeong; Narayanan, N T; Ajayan, Pulickel M; Terrones, Mauricio; Aliev, Ali; Chu, Pengfei; Zhang, Zhong; Baughman, Ray H; Chen, Yongsheng

2015-01-20

It is a challenge to fabricate graphene bulk materials with properties arising from the nature of individual graphene sheets, and which assemble into monolithic three-dimensional structures. Here we report the scalable self-assembly of randomly oriented graphene sheets into additive-free, essentially homogenous graphene sponge materials that provide a combination of both cork-like and rubber-like properties. These graphene sponges, with densities similar to air, display Poisson's ratios in all directions that are near-zero and largely strain-independent during reversible compression to giant strains. And at the same time, they function as enthalpic rubbers, which can recover up to 98% compression in air and 90% in liquids, and operate between -196 and 900 °C. Furthermore, these sponges provide reversible liquid absorption for hundreds of cycles and then discharge it within seconds, while still providing an effective near-zero Poisson's ratio.

Persistently Auxetic Materials: Engineering the Poisson Ratio of 2D Self-Avoiding Membranes under Conditions of Non-Zero Anisotropic Strain.

PubMed

Ulissi, Zachary W; Govind Rajan, Ananth; Strano, Michael S

2016-08-23

Entropic surfaces represented by fluctuating two-dimensional (2D) membranes are predicted to have desirable mechanical properties when unstressed, including a negative Poisson's ratio ("auxetic" behavior). Herein, we present calculations of the strain-dependent Poisson ratio of self-avoiding 2D membranes demonstrating desirable auxetic properties over a range of mechanical strain. Finite-size membranes with unclamped boundary conditions have positive Poisson's ratio due to spontaneous non-zero mean curvature, which can be suppressed with an explicit bending rigidity in agreement with prior findings. Applying longitudinal strain along a singular axis to this system suppresses this mean curvature and the entropic out-of-plane fluctuations, resulting in a molecular-scale mechanism for realizing a negative Poisson's ratio above a critical strain, with values significantly more negative than the previously observed zero-strain limit for infinite sheets. We find that auxetic behavior persists over surprisingly high strains of more than 20% for the smallest surfaces, with desirable finite-size scaling producing surfaces with negative Poisson's ratio over a wide range of strains. These results promise the design of surfaces and composite materials with tunable Poisson's ratio by prestressing platelet inclusions or controlling the surface rigidity of a matrix of 2D materials.

Modeling Associations between Principals’ Reported Indoor Environmental Quality and Students’ Self-Reported Respiratory Health Outcomes Using GLMM and ZIP Models

PubMed Central

Toyinbo, Oluyemi; Matilainen, Markus; Turunen, Mari; Putus, Tuula; Shaughnessy, Richard; Haverinen-Shaughnessy, Ulla

2016-01-01

Background: The aim of this paper was to examine associations between school building characteristics, indoor environmental quality (IEQ), and health responses using questionnaire data from both school principals and students. Methods: From 334 randomly sampled schools, 4248 sixth grade students from 297 schools participated in a questionnaire. From these schools, 134 principals returned questionnaires concerning 51 IEQ related questions of their school. Generalized linear mixed models (GLMM) were used to study the associations between IEQ indicators and existence of self-reported upper respiratory symptoms, while hierarchical Zero Inflated Poisson (ZIP)—models were used to model the number of symptoms. Results: Significant associations were established between existence of upper respiratory symptoms and unsatisfactory classroom temperature during the heating season (ORs 1.45 for too hot and cold, and 1.27 for too cold as compared to satisfactory temperature) and dampness or moisture damage during the year 2006–2007 (OR: 1.80 as compared to no moisture damage), respectively. The number of upper respiratory symptoms was significantly associated with inadequate ventilation and dampness or moisture damage. A higher number of missed school days due to respiratory infections were reported in schools with inadequate ventilation (RR: 1.16). Conclusions: The school level IEQ indicator variables described in this paper could explain a relatively large part of the school level variation observed in the self-reported upper respiratory symptoms and missed school days due to respiratory infections among students. PMID:27043595

Extending the Applicability of the Generalized Likelihood Function for Zero-Inflated Data Series

NASA Astrophysics Data System (ADS)

Oliveira, Debora Y.; Chaffe, Pedro L. B.; Sá, João. H. M.

2018-03-01

Proper uncertainty estimation for data series with a high proportion of zero and near zero observations has been a challenge in hydrologic studies. This technical note proposes a modification to the Generalized Likelihood function that accounts for zero inflation of the error distribution (ZI-GL). We compare the performance of the proposed ZI-GL with the original Generalized Likelihood function using the entire data series (GL) and by simply suppressing zero observations (GLy>0). These approaches were applied to two interception modeling examples characterized by data series with a significant number of zeros. The ZI-GL produced better uncertainty ranges than the GL as measured by the precision, reliability and volumetric bias metrics. The comparison between ZI-GL and GLy>0 highlights the need for further improvement in the treatment of residuals from near zero simulations when a linear heteroscedastic error model is considered. Aside from the interception modeling examples illustrated herein, the proposed ZI-GL may be useful for other hydrologic studies, such as for the modeling of the runoff generation in hillslopes and ephemeral catchments.

On the Singularity of the Vlasov-Poisson System

DOE Office of Scientific and Technical Information (OSTI.GOV)

and Hong Qin, Jian Zheng

2013-04-26

The Vlasov-Poisson system can be viewed as the collisionless limit of the corresponding Fokker- Planck-Poisson system. It is reasonable to expect that the result of Landau damping can also be obtained from the Fokker-Planck-Poisson system when the collision frequency v approaches zero. However, we show that the colllisionless Vlasov-Poisson system is a singular limit of the collisional Fokker-Planck-Poisson system, and Landau's result can be recovered only as the approaching zero from the positive side.

On the singularity of the Vlasov-Poisson system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jian; Qin, Hong; Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08550

2013-09-15

The Vlasov-Poisson system can be viewed as the collisionless limit of the corresponding Fokker-Planck-Poisson system. It is reasonable to expect that the result of Landau damping can also be obtained from the Fokker-Planck-Poisson system when the collision frequency ν approaches zero. However, we show that the collisionless Vlasov-Poisson system is a singular limit of the collisional Fokker-Planck-Poisson system, and Landau's result can be recovered only as the ν approaches zero from the positive side.

A review and comparison of Bayesian and likelihood-based inferences in beta regression and zero-or-one-inflated beta regression.

PubMed

Liu, Fang; Eugenio, Evercita C

2018-04-01

Beta regression is an increasingly popular statistical technique in medical research for modeling of outcomes that assume values in (0, 1), such as proportions and patient reported outcomes. When outcomes take values in the intervals [0,1), (0,1], or [0,1], zero-or-one-inflated beta (zoib) regression can be used. We provide a thorough review on beta regression and zoib regression in the modeling, inferential, and computational aspects via the likelihood-based and Bayesian approaches. We demonstrate the statistical and practical importance of correctly modeling the inflation at zero/one rather than ad hoc replacing them with values close to zero/one via simulation studies; the latter approach can lead to biased estimates and invalid inferences. We show via simulation studies that the likelihood-based approach is computationally faster in general than MCMC algorithms used in the Bayesian inferences, but runs the risk of non-convergence, large biases, and sensitivity to starting values in the optimization algorithm especially with clustered/correlated data, data with sparse inflation at zero and one, and data that warrant regularization of the likelihood. The disadvantages of the regular likelihood-based approach make the Bayesian approach an attractive alternative in these cases. Software packages and tools for fitting beta and zoib regressions in both the likelihood-based and Bayesian frameworks are also reviewed.

An application of a zero-inflated lifetime distribution with multiple and incomplete data sources

DOE PAGES

Hamada, M. S.; Margevicius, K. J.

2016-02-11

In this study, we analyze data sampled from a population of parts in which an associated anomaly can occur at assembly or after assembly. Using a zero-inflated lifetime distribution to fit left-censored and right-censored data as well data from a supplementary sample, we make predictions about the proportion of the population with anomalies today and in the future. Goodness-of-fit is also addressed.

Zero-truncated panel Poisson mixture models: Estimating the impact on tourism benefits in Fukushima Prefecture.

PubMed

Narukawa, Masaki; Nohara, Katsuhito

2018-04-01

This study proposes an estimation approach to panel count data, truncated at zero, in order to apply a contingent behavior travel cost method to revealed and stated preference data collected via a web-based survey. We develop zero-truncated panel Poisson mixture models by focusing on respondents who visited a site. In addition, we introduce an inverse Gaussian distribution to unobserved individual heterogeneity as an alternative to a popular gamma distribution, making it possible to capture effectively the long tail typically observed in trip data. We apply the proposed method to estimate the impact on tourism benefits in Fukushima Prefecture as a result of the Fukushima Nuclear Power Plant No. 1 accident. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bioinformatic analyses implicate the collaborating meiotic crossover/chiasma proteins Zip2, Zip3, and Spo22/Zip4 in ubiquitin labeling

PubMed Central

Perry, Jason; Kleckner, Nancy; Börner, G. Valentin

2005-01-01

Zip2 and Zip3 are meiosis-specific proteins that, in collaboration with several partners, act at the sites of crossover-designated, axis-associated recombinational interactions to mediate crossover/chiasma formation. Here, Spo22 (also called Zip4) is identified as a probable functional collaborator of Zip2/3. The molecular roles of Zip2, Zip3, and Spo22/Zip4 are unknown. All three proteins are part of a small evolutionary cohort comprising similar homologs in four related yeasts. Zip3 is shown to contain a RING finger whose structural features most closely match those of known ubiquitin E3s. Further, Zip3 exhibits major domainal homologies to Rad18, a known DNA-binding ubiquitin E3. Also described is an approach to the identification and mapping of repeated protein sequence motifs, Alignment Based Repeat Annotation (ABRA), that we have developed. When ABRA is applied to Zip2 and Spo22/Zip4, they emerge as a 14-blade WD40-like repeat protein and a 22-unit tetratricopeptide repeat protein, respectively. WD40 repeats of Cdc20, Cdh1, and Cdc16 and tetratricopeptide repeats of Cdc16, Cdc23, and Cdc27, all components of the anaphase-promoting complex, are also analyzed. These and other findings suggest that Zip2, Zip3, and Zip4 act together to mediate a process that involves Zip3-mediated ubiquitin labeling, potentially as a unique type of ubiquitin-conjugating complex. PMID:16314568

Some considerations for excess zeroes in substance abuse research.

PubMed

Bandyopadhyay, Dipankar; DeSantis, Stacia M; Korte, Jeffrey E; Brady, Kathleen T

2011-09-01

Count data collected in substance abuse research often come with an excess of "zeroes," which are typically handled using zero-inflated regression models. However, there is a need to consider the design aspects of those studies before using such a statistical model to ascertain the sources of zeroes. We sought to illustrate hurdle models as alternatives to zero-inflated models to validate a two-stage decision-making process in situations of "excess zeroes." We use data from a study of 45 cocaine-dependent subjects where the primary scientific question was to evaluate whether study participation influences drug-seeking behavior. The outcome, "the frequency (count) of cocaine use days per week," is bounded (ranging from 0 to 7). We fit and compare binomial, Poisson, negative binomial, and the hurdle version of these models to study the effect of gender, age, time, and study participation on cocaine use. The hurdle binomial model provides the best fit. Gender and time are not predictive of use. Higher odds of use versus no use are associated with age; however once use is experienced, odds of further use decrease with increase in age. Participation was associated with higher odds of no-cocaine use; once there is use, participation reduced the odds of further use. Age and study participation are significantly predictive of cocaine-use behavior. The two-stage decision process as modeled by a hurdle binomial model (appropriate for bounded count data with excess zeroes) provides interesting insights into the study of covariate effects on count responses of substance use, when all enrolled subjects are believed to be "at-risk" of use.

Two Cassava Basic Leucine Zipper (bZIP) Transcription Factors (MebZIP3 and MebZIP5) Confer Disease Resistance against Cassava Bacterial Blight.

PubMed

Li, Xiaolin; Fan, Shuhong; Hu, Wei; Liu, Guoyin; Wei, Yunxie; He, Chaozu; Shi, Haitao

2017-01-01

Basic domain-leucine zipper (bZIP) transcription factor, one type of conserved gene family, plays an important role in plant development and stress responses. Although 77 MebZIPs have been genome-wide identified in cassava, their in vivo roles remain unknown. In this study, we analyzed the expression pattern and the function of two MebZIPs ( MebZIP3 and MebZIP5 ) in response to pathogen infection. Gene expression analysis indicated that MebZIP3 and MebZIP5 were commonly regulated by flg22, Xanthomonas axonopodis pv. manihotis ( Xam ), salicylic acid (SA), and hydrogen peroxide (H 2 O 2 ). Subcellular localization analysis showed that MebZIP3 and MebZIP5 are specifically located in cell nucleus. Through overexpression in tobacco, we found that MebZIP3 and MebZIP5 conferred improved disease resistance against cassava bacterial blight, with more callose depositions. On the contrary, MebZIP3- and MebZIP5 -silenced plants by virus-induced gene silencing (VIGS) showed disease sensitive phenotype, lower transcript levels of defense-related genes and less callose depositions. Taken together, this study highlights the positive role of MebZIP3 and MebZIP5 in disease resistance against cassava bacterial blight for further utilization in genetic improvement of cassava disease resistance.

Zero inflation in ordinal data: Incorporating susceptibility to response through the use of a mixture model

PubMed Central

Kelley, Mary E.; Anderson, Stewart J.

2008-01-01

Summary The aim of the paper is to produce a methodology that will allow users of ordinal scale data to more accurately model the distribution of ordinal outcomes in which some subjects are susceptible to exhibiting the response and some are not (i.e., the dependent variable exhibits zero inflation). This situation occurs with ordinal scales in which there is an anchor that represents the absence of the symptom or activity, such as “none”, “never” or “normal”, and is particularly common when measuring abnormal behavior, symptoms, and side effects. Due to the unusually large number of zeros, traditional statistical tests of association can be non-informative. We propose a mixture model for ordinal data with a built-in probability of non-response that allows modeling of the range (e.g., severity) of the scale, while simultaneously modeling the presence/absence of the symptom. Simulations show that the model is well behaved and a likelihood ratio test can be used to choose between the zero-inflated and the traditional proportional odds model. The model, however, does have minor restrictions on the nature of the covariates that must be satisfied in order for the model to be identifiable. The method is particularly relevant for public health research such as large epidemiological surveys where more careful documentation of the reasons for response may be difficult. PMID:18351711

Multinomial model and zero-inflated gamma model to study time spent on leisure time physical activity: an example of ELSA-Brasil.

PubMed

Nobre, Aline Araújo; Carvalho, Marilia Sá; Griep, Rosane Härter; Fonseca, Maria de Jesus Mendes da; Melo, Enirtes Caetano Prates; Santos, Itamar de Souza; Chor, Dora

2017-08-17

To compare two methodological approaches: the multinomial model and the zero-inflated gamma model, evaluating the factors associated with the practice and amount of time spent on leisure time physical activity. Data collected from 14,823 baseline participants in the Longitudinal Study of Adult Health (ELSA-Brasil - Estudo Longitudinal de Saúde do Adulto ) have been analysed. Regular leisure time physical activity has been measured using the leisure time physical activity module of the International Physical Activity Questionnaire. The explanatory variables considered were gender, age, education level, and annual per capita family income. The main advantage of the zero-inflated gamma model over the multinomial model is that it estimates mean time (minutes per week) spent on leisure time physical activity. For example, on average, men spent 28 minutes/week longer on leisure time physical activity than women did. The most sedentary groups were young women with low education level and income. The zero-inflated gamma model, which is rarely used in epidemiological studies, can give more appropriate answers in several situations. In our case, we have obtained important information on the main determinants of the duration of leisure time physical activity. This information can help guide efforts towards the most vulnerable groups since physical inactivity is associated with different diseases and even premature death.

A Spatial Poisson Hurdle Model for Exploring Geographic Variation in Emergency Department Visits

PubMed Central

Neelon, Brian; Ghosh, Pulak; Loebs, Patrick F.

2012-01-01

Summary We develop a spatial Poisson hurdle model to explore geographic variation in emergency department (ED) visits while accounting for zero inflation. The model consists of two components: a Bernoulli component that models the probability of any ED use (i.e., at least one ED visit per year), and a truncated Poisson component that models the number of ED visits given use. Together, these components address both the abundance of zeros and the right-skewed nature of the nonzero counts. The model has a hierarchical structure that incorporates patient- and area-level covariates, as well as spatially correlated random effects for each areal unit. Because regions with high rates of ED use are likely to have high expected counts among users, we model the spatial random effects via a bivariate conditionally autoregressive (CAR) prior, which introduces dependence between the components and provides spatial smoothing and sharing of information across neighboring regions. Using a simulation study, we show that modeling the between-component correlation reduces bias in parameter estimates. We adopt a Bayesian estimation approach, and the model can be fit using standard Bayesian software. We apply the model to a study of patient and neighborhood factors influencing emergency department use in Durham County, North Carolina. PMID:23543242

Selecting the right statistical model for analysis of insect count data by using information theoretic measures.

PubMed

Sileshi, G

2006-10-01

Researchers and regulatory agencies often make statistical inferences from insect count data using modelling approaches that assume homogeneous variance. Such models do not allow for formal appraisal of variability which in its different forms is the subject of interest in ecology. Therefore, the objectives of this paper were to (i) compare models suitable for handling variance heterogeneity and (ii) select optimal models to ensure valid statistical inferences from insect count data. The log-normal, standard Poisson, Poisson corrected for overdispersion, zero-inflated Poisson, the negative binomial distribution and zero-inflated negative binomial models were compared using six count datasets on foliage-dwelling insects and five families of soil-dwelling insects. Akaike's and Schwarz Bayesian information criteria were used for comparing the various models. Over 50% of the counts were zeros even in locally abundant species such as Ootheca bennigseni Weise, Mesoplatys ochroptera Stål and Diaecoderus spp. The Poisson model after correction for overdispersion and the standard negative binomial distribution model provided better description of the probability distribution of seven out of the 11 insects than the log-normal, standard Poisson, zero-inflated Poisson or zero-inflated negative binomial models. It is concluded that excess zeros and variance heterogeneity are common data phenomena in insect counts. If not properly modelled, these properties can invalidate the normal distribution assumptions resulting in biased estimation of ecological effects and jeopardizing the integrity of the scientific inferences. Therefore, it is recommended that statistical models appropriate for handling these data properties be selected using objective criteria to ensure efficient statistical inference.

Unified Computational Methods for Regression Analysis of Zero-Inflated and Bound-Inflated Data

PubMed Central

Yang, Yan; Simpson, Douglas

2010-01-01

Bounded data with excess observations at the boundary are common in many areas of application. Various individual cases of inflated mixture models have been studied in the literature for bound-inflated data, yet the computational methods have been developed separately for each type of model. In this article we use a common framework for computing these models, and expand the range of models for both discrete and semi-continuous data with point inflation at the lower boundary. The quasi-Newton and EM algorithms are adapted and compared for estimation of model parameters. The numerical Hessian and generalized Louis method are investigated as means for computing standard errors after optimization. Correlated data are included in this framework via generalized estimating equations. The estimation of parameters and effectiveness of standard errors are demonstrated through simulation and in the analysis of data from an ultrasound bioeffect study. The unified approach enables reliable computation for a wide class of inflated mixture models and comparison of competing models. PMID:20228950

Zero-truncated negative binomial - Erlang distribution

NASA Astrophysics Data System (ADS)

Bodhisuwan, Winai; Pudprommarat, Chookait; Bodhisuwan, Rujira; Saothayanun, Luckhana

2017-11-01

The zero-truncated negative binomial-Erlang distribution is introduced. It is developed from negative binomial-Erlang distribution. In this work, the probability mass function is derived and some properties are included. The parameters of the zero-truncated negative binomial-Erlang distribution are estimated by using the maximum likelihood estimation. Finally, the proposed distribution is applied to real data, the number of methamphetamine in the Bangkok, Thailand. Based on the results, it shows that the zero-truncated negative binomial-Erlang distribution provided a better fit than the zero-truncated Poisson, zero-truncated negative binomial, zero-truncated generalized negative-binomial and zero-truncated Poisson-Lindley distributions for this data.

Expression Profile Analysis of Zinc Transporters (ZIP4, ZIP9, ZIP11, ZnT9) in Gliomas and their Correlation with IDH1 Mutation Status.

PubMed

Kang, Xing; Chen, Rong; Zhang, Jie; Li, Gang; Dai, Peng-Gao; Chen, Chao; Wang, Hui-Juan

2015-01-01

Zinc transporters have been considered as essential regulators in many cancers; however, their mechanisms remain unknown, especially in gliomas. Isocitrate dehydrogenase 1(IDH1) mutation is crucial to glioma. This study aimed to investigate whether zinc transporters are correlated with glioma grade and IDH1 mutation status. IDH1 mutation status and mRNA expression of four zinc transporters (ZIP4, ZIP9, ZIP11, and ZnT9) were determined by subjecting a panel of 74 glioma tissue samples to quantitative real-time PCR and pyrosequencing. The correlations between the expression levels of these zinc transporter genes and the grade of glioma, as well as IDH1 mutation status, were investigated. Among the four zinc transporter genes, high ZIP4 expression and low ZIP11 expression were significantly associated with higher grade (grades III and IV) tumors compared with lower grade (grades I and II) counterparts (p<0.0001). However, only ZIP11 exhibited weak correlation with IDH1 mutation status (p=0.045). Samples with mutations in IDH1 displayed higher ZIP11 expression than those without IDH1 mutations. This finding indicated that zinc transporters may interact with IDH1 mutation by direct modulation or action in some shared pathways or genes to promote the development of glioma. Zinc transporters may play an important role in glioma. ZIP4 and ZIP11 are promising molecular diagnostic markers and novel therapeutic targets. Nevertheless, the detailed biological function of zinc transporters and the mechanism of the potential interaction between ZIP11 and IDH1 mutation in gliomagenesis should be further investigated.

MIXED MODEL AND ESTIMATING EQUATION APPROACHES FOR ZERO INFLATION IN CLUSTERED BINARY RESPONSE DATA WITH APPLICATION TO A DATING VIOLENCE STUDY1

PubMed Central

Fulton, Kara A.; Liu, Danping; Haynie, Denise L.; Albert, Paul S.

2016-01-01

The NEXT Generation Health study investigates the dating violence of adolescents using a survey questionnaire. Each student is asked to affirm or deny multiple instances of violence in his/her dating relationship. There is, however, evidence suggesting that students not in a relationship responded to the survey, resulting in excessive zeros in the responses. This paper proposes likelihood-based and estimating equation approaches to analyze the zero-inflated clustered binary response data. We adopt a mixed model method to account for the cluster effect, and the model parameters are estimated using a maximum-likelihood (ML) approach that requires a Gaussian–Hermite quadrature (GHQ) approximation for implementation. Since an incorrect assumption on the random effects distribution may bias the results, we construct generalized estimating equations (GEE) that do not require the correct specification of within-cluster correlation. In a series of simulation studies, we examine the performance of ML and GEE methods in terms of their bias, efficiency and robustness. We illustrate the importance of properly accounting for this zero inflation by reanalyzing the NEXT data where this issue has previously been ignored. PMID:26937263

Modeling number of claims and prediction of total claim amount

NASA Astrophysics Data System (ADS)

Acar, Aslıhan Şentürk; Karabey, Uǧur

2017-07-01

In this study we focus on annual number of claims of a private health insurance data set which belongs to a local insurance company in Turkey. In addition to Poisson model and negative binomial model, zero-inflated Poisson model and zero-inflated negative binomial model are used to model the number of claims in order to take into account excess zeros. To investigate the impact of different distributional assumptions for the number of claims on the prediction of total claim amount, predictive performances of candidate models are compared by using root mean square error (RMSE) and mean absolute error (MAE) criteria.

Analysis of overdispersed count data: application to the Human Papillomavirus Infection in Men (HIM) Study.

PubMed

Lee, J-H; Han, G; Fulp, W J; Giuliano, A R

2012-06-01

The Poisson model can be applied to the count of events occurring within a specific time period. The main feature of the Poisson model is the assumption that the mean and variance of the count data are equal. However, this equal mean-variance relationship rarely occurs in observational data. In most cases, the observed variance is larger than the assumed variance, which is called overdispersion. Further, when the observed data involve excessive zero counts, the problem of overdispersion results in underestimating the variance of the estimated parameter, and thus produces a misleading conclusion. We illustrated the use of four models for overdispersed count data that may be attributed to excessive zeros. These are Poisson, negative binomial, zero-inflated Poisson and zero-inflated negative binomial models. The example data in this article deal with the number of incidents involving human papillomavirus infection. The four models resulted in differing statistical inferences. The Poisson model, which is widely used in epidemiology research, underestimated the standard errors and overstated the significance of some covariates.

Characterization of pollen-expressed bZIP protein interactions and the role of ATbZIP18 in the male gametophyte.

PubMed

Gibalová, Antónia; Steinbachová, Lenka; Hafidh, Said; Bláhová, Veronika; Gadiou, Zuzana; Michailidis, Christos; Műller, Karel; Pleskot, Roman; Dupľáková, Nikoleta; Honys, David

2017-03-01

KEY MESSAGE : bZIP TF network in pollen. Transcriptional control of gene expression represents an important mechanism guiding organisms through developmental processes and providing plasticity towards environmental stimuli. Because of their sessile nature, plants require effective gene regulation for rapid response to variation in environmental and developmental conditions. Transcription factors (TFs) provide such control ensuring correct gene expression in spatial and temporal manner. Our work reports the interaction network of six bZIP TFs expressed in Arabidopsis thaliana pollen and highlights the potential functional role for AtbZIP18 in pollen. AtbZIP18 was shown to interact with three other pollen-expressed bZIP TFs-AtbZIP34, AtbZIP52, and AtbZIP61 in yeast two-hybrid assays. AtbZIP18 transcripts are highly expressed in pollen, and at the subcellular level, an AtbZIP18-GFP fusion protein was located in the nucleus and cytoplasm/ER. To address the role of AtbZIP18 in the male gametophyte, we performed phenotypic analysis of a T-DNA knockout allele, which showed slightly reduced transmission through the male gametophyte. Some of the phenotype defects in atbzip18 pollen, although observed at low penetrance, were similar to those seen at higher frequency in the T-DNA knockout of the interacting partner, AtbZIP34. To gain deeper insight into the regulatory role of AtbZIP18, we analysed atbzip18/- pollen microarray data. Our results point towards a potential repressive role for AtbZIP18 and its functional redundancy with AtbZIP34 in pollen.

A Ramie bZIP Transcription Factor BnbZIP2 Is Involved in Drought, Salt, and Heavy Metal Stress Response.

PubMed

Huang, Chengjian; Zhou, Jinghua; Jie, Yucheng; Xing, Hucheng; Zhong, Yingli; Yu, Weilin; She, Wei; Ma, Yushen; Liu, Zehang; Zhang, Ying

2016-12-01

bZIP transcription factors play key roles in plant growth, development, and stress signaling. A bZIP gene BnbZIP2 (GenBank accession number: KP642148) was cloned from ramie. BnbZIP2 has a 1416 base pair open reading frame, encoding a 471 amino acid protein containing a characteristic bZIP domain and a leucine zipper. BnbZIP2 shares high sequence similarity with bZIP factors from other plants. The BnbZIP2 protein is localized to both nuclei and cytoplasm. Transcripts of BnbZIP2 were found in various tissues in ramie, with significantly higher levels in female and male flowers. Its expression was induced by drought, high salinity, and abscisic acid treatments. Analysis of the cis-elements in promoters of BnbZIP2 identified cis-acting elements involved in growth, developmental processes, and a variety of stress responses. Transgenic Arabidopsis plants' overexpression of BnbZIP2 exhibited more sensitivity to drought and heavy metal Cd stress during seed germination, whereas more tolerance to high-salinity stress than the wild type during both seed germination and plant development. Thus, BnbZIP2 may act as a positive regulator in plants' response to high-salinity stress and be an important candidate gene for molecular breeding of salt-tolerant plants.

Functional analysis RaZIP1 transporter of the ZIP family from the ectomycorrhizal Zn-accumulating Russula atropurpurea.

PubMed

Leonhardt, Tereza; Sácký, Jan; Kotrba, Pavel

2018-04-01

A search of R. atropurpurea transcriptome for sequences encoding the transporters of the Zrt-, Irt-like Protein (ZIP) family, which are in eukaryotes integral to Zn supply into cytoplasm, allowed the identification of RaZIP1 cDNA with a predicted product belonging to ZIP I subfamily; it was subjected to functional studies in mutant Saccharomyces cerevisiae strains. The expression of RaZIP1, but not RaZIP1 H208A or RaZIP1 H232A mutants lacking conserved-among-ZIPs transmembrane histidyls, complemented Zn uptake deficiency in zrt1Δzrt2Δ yeasts. RaZIP1 substantially increased cellular Zn uptake in this strain and added to Zn sensitivity in zrc1Δcot1Δ mutant. The Fe uptake deficiency in ftr1Δ strain was not rescued and Mn uptake was insufficient for toxicity in Mn-sensitive pmr1Δ yeasts. By contrast, RaZIP1 increased Cd sensitivity in yap1Δ strain and conferred Cd transport activity in yeasts, albeit with substantially lower efficiency compared to Zn transport. In metal uptake assays, the accumulation of Zn in zrt1Δzrt2Δ strain remained unaffected by Cd, Fe, and Mn present in 20-fold molar excess over Zn. Immunofluorescence microscopy detected functional hemagglutinin-tagged HA::RaZIP1 on the yeast cell protoplast periphery. Altogether, these data indicate that RaZIP1 is a high-affinity plasma membrane transporter specialized in Zn uptake, and improve the understanding of the cellular and molecular biology of Zn in R. atropurpurea that is known for its ability to accumulate remarkably high concentrations of Zn.

A ZIP6-ZIP10 heteromer controls NCAM1 phosphorylation and integration into focal adhesion complexes during epithelial-to-mesenchymal transition.

PubMed

Brethour, Dylan; Mehrabian, Mohadeseh; Williams, Declan; Wang, Xinzhu; Ghodrati, Farinaz; Ehsani, Sepehr; Rubie, Elizabeth A; Woodgett, James R; Sevalle, Jean; Xi, Zhengrui; Rogaeva, Ekaterina; Schmitt-Ulms, Gerold

2017-01-18

The prion protein (PrP) evolved from the subbranch of ZIP metal ion transporters comprising ZIPs 5, 6 and 10, raising the prospect that the study of these ZIPs may reveal insights relevant for understanding the function of PrP. Building on data which suggested PrP and ZIP6 are critical during epithelial-to-mesenchymal transition (EMT), we investigated ZIP6 in an EMT paradigm using ZIP6 knockout cells, mass spectrometry and bioinformatic methods. Reminiscent of PrP, ZIP6 levels are five-fold upregulated during EMT and the protein forms a complex with NCAM1. ZIP6 also interacts with ZIP10 and the two ZIP transporters exhibit interdependency during their expression. ZIP6 contributes to the integration of NCAM1 in focal adhesion complexes but, unlike cells lacking PrP, ZIP6 deficiency does not abolish polysialylation of NCAM1. Instead, ZIP6 mediates phosphorylation of NCAM1 on a cluster of cytosolic acceptor sites. Substrate consensus motif features and in vitro phosphorylation data point toward GSK3 as the kinase responsible, and interface mapping experiments identified histidine-rich cytoplasmic loops within the ZIP6/ZIP10 heteromer as a novel scaffold for GSK3 binding. Our data suggests that PrP and ZIP6 inherited the ability to interact with NCAM1 from their common ZIP ancestors but have since diverged to control distinct posttranslational modifications of NCAM1.

A smooth exit from eternal inflation?

NASA Astrophysics Data System (ADS)

Hawking, S. W.; Hertog, Thomas

2018-04-01

The usual theory of inflation breaks down in eternal inflation. We derive a dual description of eternal inflation in terms of a deformed Euclidean CFT located at the threshold of eternal inflation. The partition function gives the amplitude of different geometries of the threshold surface in the no-boundary state. Its local and global behavior in dual toy models shows that the amplitude is low for surfaces which are not nearly conformal to the round three-sphere and essentially zero for surfaces with negative curvature. Based on this we conjecture that the exit from eternal inflation does not produce an infinite fractal-like multiverse, but is finite and reasonably smooth.

A tutorial on count regression and zero-altered count models for longitudinal substance use data

PubMed Central

Atkins, David C.; Baldwin, Scott A.; Zheng, Cheng; Gallop, Robert J.; Neighbors, Clayton

2012-01-01

Critical research questions in the study of addictive behaviors concern how these behaviors change over time - either as the result of intervention or in naturalistic settings. The combination of count outcomes that are often strongly skewed with many zeroes (e.g., days using, number of total drinks, number of drinking consequences) with repeated assessments (e.g., longitudinal follow-up after intervention or daily diary data) present challenges for data analyses. The current article provides a tutorial on methods for analyzing longitudinal substance use data, focusing on Poisson, zero-inflated, and hurdle mixed models, which are types of hierarchical or multilevel models. Two example datasets are used throughout, focusing on drinking-related consequences following an intervention and daily drinking over the past 30 days, respectively. Both datasets as well as R, SAS, Mplus, Stata, and SPSS code showing how to fit the models are available on a supplemental website. PMID:22905895

Automatic processes in at-risk adolescents: the role of alcohol-approach tendencies and response inhibition in drinking behavior.

PubMed

Peeters, Margot; Wiers, Reinout W; Monshouwer, Karin; van de Schoot, Rens; Janssen, Tim; Vollebergh, Wilma A M

2012-11-01

This study examined the association between automatic processes and drinking behavior in relation to individual differences in response inhibition in young adolescents who had just started drinking. It was hypothesized that strong automatic behavioral tendencies toward alcohol-related stimuli (alcohol-approach bias) were associated with higher levels of alcohol use, especially amongst adolescents with relatively weak inhibition skills. To test this hypothesis structural equation analyses (standard error of mean) were performed using a zero inflated Poisson (ZIP) model. A well-known problem in studying risk behavior is the low incidence rate resulting in a zero dominated distribution. A ZIP-model accounts for non-normality of the data. Adolescents were selected from secondary Special Education schools (a risk group for the development of substance use problems). Participants were 374 adolescents (mean age of M = 13.6 years). Adolescents completed the alcohol approach avoidance task (a-AAT), the Stroop colour naming task (Stroop) and a questionnaire that assessed alcohol use. The ZIP-model established stronger alcohol-approach tendencies for adolescent drinkers (P < 0.01) and the interaction revealed a stronger effect of alcohol-approach tendencies on alcohol use in the absence of good inhibition skills (P < 0.05). Automatically-activated cognitive processes are associated with the drinking behavior of young, at-risk adolescents. It appears that alcohol-approach tendencies are formed shortly after the initiation of drinking and particularly affect the drinking behavior of adolescents with relatively weak inhibition skills. Implications for the prevention of problem drinking in adolescents are discussed. © 2012 The Authors. Addiction © 2012 Society for the Study of Addiction.

Bayesian spatiotemporal analysis of zero-inflated biological population density data by a delta-normal spatiotemporal additive model.

PubMed

Arcuti, Simona; Pollice, Alessio; Ribecco, Nunziata; D'Onghia, Gianfranco

2016-03-01

We evaluate the spatiotemporal changes in the density of a particular species of crustacean known as deep-water rose shrimp, Parapenaeus longirostris, based on biological sample data collected during trawl surveys carried out from 1995 to 2006 as part of the international project MEDITS (MEDiterranean International Trawl Surveys). As is the case for many biological variables, density data are continuous and characterized by unusually large amounts of zeros, accompanied by a skewed distribution of the remaining values. Here we analyze the normalized density data by a Bayesian delta-normal semiparametric additive model including the effects of covariates, using penalized regression with low-rank thin-plate splines for nonlinear spatial and temporal effects. Modeling the zero and nonzero values by two joint processes, as we propose in this work, allows to obtain great flexibility and easily handling of complex likelihood functions, avoiding inaccurate statistical inferences due to misclassification of the high proportion of exact zeros in the model. Bayesian model estimation is obtained by Markov chain Monte Carlo simulations, suitably specifying the complex likelihood function of the zero-inflated density data. The study highlights relevant nonlinear spatial and temporal effects and the influence of the annual Mediterranean oscillations index and of the sea surface temperature on the distribution of the deep-water rose shrimp density. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The role of ZIP transporters and group F bZIP transcription factors in the Zn-deficiency response of wheat (Triticum aestivum).

PubMed

Evens, Nicholas P; Buchner, Peter; Williams, Lorraine E; Hawkesford, Malcolm J

2017-10-01

Understanding the molecular basis of zinc (Zn) uptake and transport in staple cereal crops is critical for improving both Zn content and tolerance to low-Zn soils. This study demonstrates the importance of group F bZIP transcription factors and ZIP transporters in responses to Zn deficiency in wheat (Triticum aestivum). Seven group F TabZIP genes and 14 ZIPs with homeologs were identified in hexaploid wheat. Promoter analysis revealed the presence of Zn-deficiency-response elements (ZDREs) in a number of the ZIPs. Functional complementation of the zrt1/zrt2 yeast mutant by TaZIP3, -6, -7, -9 and -13 supported an ability to transport Zn. Group F TabZIPs contain the group-defining cysteine-histidine-rich motifs, which are the predicted binding site of Zn 2+ in the Zn-deficiency response. Conservation of these motifs varied between the TabZIPs suggesting that individual TabZIPs may have specific roles in the wheat Zn-homeostatic network. Increased expression in response to low Zn levels was observed for several of the wheat ZIPs and bZIPs; this varied temporally and spatially suggesting specific functions in the response mechanism. The ability of the group F TabZIPs to bind to specific ZDREs in the promoters of TaZIPs indicates a conserved mechanism in monocots and dicots in responding to Zn deficiency. In support of this, TabZIPF1-7DL and TabZIPF4-7AL afforded a strong level of rescue to the Arabidopsis hypersensitive bzip19 bzip23 double mutant under Zn deficiency. These results provide a greater understanding of Zn-homeostatic mechanisms in wheat, demonstrating an expanded repertoire of group F bZIP transcription factors, adding to the complexity of Zn homeostasis. © 2017 The Authors The Plant Journal published by John Wiley & Sons Ltd and Society for Experimental Biology.

Dark energy from gravitoelectromagnetic inflation?

NASA Astrophysics Data System (ADS)

Membiela, F. A.; Bellini, M.

2008-02-01

Gravitoectromagnetic Inflation (GI) was introduced to describe in an unified manner, electromagnetic, gravitatory and inflaton fields from a 5D vacuum state. On the other hand, the primordial origin and evolution of dark energy is today unknown. In this letter we show using GI that the zero modes of some redefined vector fields $B_i=A_i/a$ produced during inflation, could be the source of dark energy in the universe.

Variable selection for zero-inflated and overdispersed data with application to health care demand in Germany

PubMed Central

Wang, Zhu; Shuangge, Ma; Wang, Ching-Yun

2017-01-01

In health services and outcome research, count outcomes are frequently encountered and often have a large proportion of zeros. The zero-inflated negative binomial (ZINB) regression model has important applications for this type of data. With many possible candidate risk factors, this paper proposes new variable selection methods for the ZINB model. We consider maximum likelihood function plus a penalty including the least absolute shrinkage and selection operator (LASSO), smoothly clipped absolute deviation (SCAD) and minimax concave penalty (MCP). An EM (expectation-maximization) algorithm is proposed for estimating the model parameters and conducting variable selection simultaneously. This algorithm consists of estimating penalized weighted negative binomial models and penalized logistic models via the coordinated descent algorithm. Furthermore, statistical properties including the standard error formulae are provided. A simulation study shows that the new algorithm not only has more accurate or at least comparable estimation, also is more robust than the traditional stepwise variable selection. The proposed methods are applied to analyze the health care demand in Germany using an open-source R package mpath. PMID:26059498

Tissue-Specific Induction of Mouse ZIP8 and ZIP14 Divalent Cation/Bicarbonate Symporters by, and Cytokine Response to, Inflammatory Signals

PubMed Central

Gálvez-Peralta, Marina; Wang, Zhifang; Bao, Shengying; Knoell, Daren L; Nebert, Daniel W

2014-01-01

Mouse Slc39a8 and Slc39a14 genes encode ZIP8 and ZIP14, respectively, which are ubiquitous divalent cation/(HCO3−)2 symporters responsible for uptake of Zn2+, Fe2+ and Mn2+ into cells. Cd2+ and other toxic nonessential metals can displace essential cations, thereby entering vertebrate cells. Whereas Slc39a8 encodes a single protein, Slc39a14 has two exons 4 which, via alternative splicing, give rise to ZIP14A and ZIP14B; why differences exist in cell-type-specific expression of ZIP14A and ZIP14B remains unknown. Inflammatory stimuli have been associated with ZIP8 and ZIP14 up-regulation, but a systematic study of many tissues simultaneously in a laboratory animal following inflammatory cytokine exposure has not yet been reported. Herein we show that C57BL/6J male mice—treated intraperitoneally with lipopolysaccharide (LPS), or the proinflammatory cytokines tumor necrosis factor (TNF) or interleukin-6 (IL6)—exhibited quantatively very different, highly tissue-specific, and markedly time-dependent up- and down-regulation of ZIP8, ZIP14A and ZIP14B mRNA levels in twelve tissues. Magnitude of the inflammatory response was confirmed by measuring the proinflammatory cytokine TNF, IL6 and interleukin-1β (IL1B) mRNA levels in the same tissues of these animals. Our data suggest that most if not all tissues use ZIP8, ZIP14A and/or ZIP14B) for Zn2+ uptake, some tissues under basal conditions and others moreso when inflammatory stressors are present; collectively, this might lead to substantial alterations in plasma Zn2+ levels, due to Zn2+ redistribution not just in liver, but across many vital organs. In the context of cadmium-mediated toxicity, our data suggest that tissues other than liver, kidney and lung should also be considered. PMID:24728862

A Novel Wheat C-bZIP Gene, TabZIP14-B, Participates in Salt and Freezing Tolerance in Transgenic Plants

PubMed Central

Zhang, Lina; Zhang, Lichao; Xia, Chuan; Gao, Lifeng; Hao, Chenyang; Zhao, Guangyao; Jia, Jizeng; Kong, Xiuying

2017-01-01

The group C-bZIP transcription factors (TFs) are involved in diverse biological processes, such as the regulation of seed storage protein (SSP) production and the responses to pathogen challenge and abiotic stress. However, our knowledge of the abiotic functions of group C-bZIP genes in wheat remains limited. Here, we present the function of a novel TabZIP14-B gene in wheat. This gene belongs to the group C-bZIP TFs and contains six exons and five introns; three haplotypes were identified among accessions of tetraploid and hexaploid wheat. A subcellular localization analysis indicated that TabZIP14-B was targeted to the nucleus of tobacco epidermal cells. A transactivation assay demonstrated that TabZIP14-B showed transcriptional activation ability and was capable of binding the abscisic acid (ABA) responsive element (ABRE) in yeast. RT-qPCR revealed that TabZIP14-B was expressed in the roots, stems, leaves, and young spikes and was up-regulated by exogenous ABA, salt, low-temperature, and polyethylene glycol (PEG) stress treatments. Furthermore, Arabidopsis plants overexpressing TabZIP14-B exhibited enhanced tolerance to salt, freezing stresses and ABA sensitivity. Overexpression of TabZIP14-B resulted in increased expression of the AtRD29A, AtCOR47, AtRD20, AtGSTF6, and AtRAB18 genes and changes in several physiological characteristics. These results suggest that TabZIP14-B could function as a positive regulator in mediating the abiotic stress response. PMID:28536588

Computation of solar perturbations with Poisson series

NASA Technical Reports Server (NTRS)

Broucke, R.

1974-01-01

Description of a project for computing first-order perturbations of natural or artificial satellites by integrating the equations of motion on a computer with automatic Poisson series expansions. A basic feature of the method of solution is that the classical variation-of-parameters formulation is used rather than rectangular coordinates. However, the variation-of-parameters formulation uses the three rectangular components of the disturbing force rather than the classical disturbing function, so that there is no problem in expanding the disturbing function in series. Another characteristic of the variation-of-parameters formulation employed is that six rather unusual variables are used in order to avoid singularities at the zero eccentricity and zero (or 90 deg) inclination. The integration process starts by assuming that all the orbit elements present on the right-hand sides of the equations of motion are constants. These right-hand sides are then simple Poisson series which can be obtained with the use of the Bessel expansions of the two-body problem in conjunction with certain interation methods. These Poisson series can then be integrated term by term, and a first-order solution is obtained.

HIV-1 Vpr Induces the Degradation of ZIP and sZIP, Adaptors of the NuRD Chromatin Remodeling Complex, by Hijacking DCAF1/VprBP

PubMed Central

Maudet, Claire; Sourisce, Adèle; Dragin, Loïc; Lahouassa, Hichem; Rain, Jean-Christophe; Bouaziz, Serge; Ramirez, Bertha Cécilia; Margottin-Goguet, Florence

2013-01-01

The Vpr protein from type 1 and type 2 Human Immunodeficiency Viruses (HIV-1 and HIV-2) is thought to inactivate several host proteins through the hijacking of the DCAF1 adaptor of the Cul4A ubiquitin ligase. Here, we identified two transcriptional regulators, ZIP and sZIP, as Vpr-binding proteins degraded in the presence of Vpr. ZIP and sZIP have been shown to act through the recruitment of the NuRD chromatin remodeling complex. Strikingly, chromatin is the only cellular fraction where Vpr is present together with Cul4A ubiquitin ligase subunits. Components of the NuRD complex and exogenous ZIP and sZIP were also associated with this fraction. Several lines of evidence indicate that Vpr induces ZIP and sZIP degradation by hijacking DCAF1: (i) Vpr induced a drastic decrease of exogenously expressed ZIP and sZIP in a dose-dependent manner, (ii) this decrease relied on the proteasome activity, (iii) ZIP or sZIP degradation was impaired in the presence of a DCAF1-binding deficient Vpr mutant or when DCAF1 expression was silenced. Vpr-mediated ZIP and sZIP degradation did not correlate with the growth-related Vpr activities, namely G2 arrest and G2 arrest-independent cytotoxicity. Nonetheless, infection with HIV-1 viruses expressing Vpr led to the degradation of the two proteins. Altogether our results highlight the existence of two host transcription factors inactivated by Vpr. The role of Vpr-mediated ZIP and sZIP degradation in the HIV-1 replication cycle remains to be deciphered. PMID:24116224

Matching the Statistical Model to the Research Question for Dental Caries Indices with Many Zero Counts.

PubMed

Preisser, John S; Long, D Leann; Stamm, John W

2017-01-01

Marginalized zero-inflated count regression models have recently been introduced for the statistical analysis of dental caries indices and other zero-inflated count data as alternatives to traditional zero-inflated and hurdle models. Unlike the standard approaches, the marginalized models directly estimate overall exposure or treatment effects by relating covariates to the marginal mean count. This article discusses model interpretation and model class choice according to the research question being addressed in caries research. Two data sets, one consisting of fictional dmft counts in 2 groups and the other on DMFS among schoolchildren from a randomized clinical trial comparing 3 toothpaste formulations to prevent incident dental caries, are analyzed with negative binomial hurdle, zero-inflated negative binomial, and marginalized zero-inflated negative binomial models. In the first example, estimates of treatment effects vary according to the type of incidence rate ratio (IRR) estimated by the model. Estimates of IRRs in the analysis of the randomized clinical trial were similar despite their distinctive interpretations. The choice of statistical model class should match the study's purpose, while accounting for the broad decline in children's caries experience, such that dmft and DMFS indices more frequently generate zero counts. Marginalized (marginal mean) models for zero-inflated count data should be considered for direct assessment of exposure effects on the marginal mean dental caries count in the presence of high frequencies of zero counts. © 2017 S. Karger AG, Basel.

Matching the Statistical Model to the Research Question for Dental Caries Indices with Many Zero Counts

PubMed Central

Preisser, John S.; Long, D. Leann; Stamm, John W.

2017-01-01

Marginalized zero-inflated count regression models have recently been introduced for the statistical analysis of dental caries indices and other zero-inflated count data as alternatives to traditional zero-inflated and hurdle models. Unlike the standard approaches, the marginalized models directly estimate overall exposure or treatment effects by relating covariates to the marginal mean count. This article discusses model interpretation and model class choice according to the research question being addressed in caries research. Two datasets, one consisting of fictional dmft counts in two groups and the other on DMFS among schoolchildren from a randomized clinical trial (RCT) comparing three toothpaste formulations to prevent incident dental caries, are analysed with negative binomial hurdle (NBH), zero-inflated negative binomial (ZINB), and marginalized zero-inflated negative binomial (MZINB) models. In the first example, estimates of treatment effects vary according to the type of incidence rate ratio (IRR) estimated by the model. Estimates of IRRs in the analysis of the RCT were similar despite their distinctive interpretations. Choice of statistical model class should match the study’s purpose, while accounting for the broad decline in children’s caries experience, such that dmft and DMFS indices more frequently generate zero counts. Marginalized (marginal mean) models for zero-inflated count data should be considered for direct assessment of exposure effects on the marginal mean dental caries count in the presence of high frequencies of zero counts. PMID:28291962

Variable selection for zero-inflated and overdispersed data with application to health care demand in Germany.

PubMed

Wang, Zhu; Ma, Shuangge; Wang, Ching-Yun

2015-09-01

In health services and outcome research, count outcomes are frequently encountered and often have a large proportion of zeros. The zero-inflated negative binomial (ZINB) regression model has important applications for this type of data. With many possible candidate risk factors, this paper proposes new variable selection methods for the ZINB model. We consider maximum likelihood function plus a penalty including the least absolute shrinkage and selection operator (LASSO), smoothly clipped absolute deviation (SCAD), and minimax concave penalty (MCP). An EM (expectation-maximization) algorithm is proposed for estimating the model parameters and conducting variable selection simultaneously. This algorithm consists of estimating penalized weighted negative binomial models and penalized logistic models via the coordinated descent algorithm. Furthermore, statistical properties including the standard error formulae are provided. A simulation study shows that the new algorithm not only has more accurate or at least comparable estimation, but also is more robust than the traditional stepwise variable selection. The proposed methods are applied to analyze the health care demand in Germany using the open-source R package mpath. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A conserved proline residue in the leucine zipper region of AtbZIP34 and AtbZIP61 in Arabidopsis thaliana interferes with the formation of homodimer.

PubMed

Shen, Huaishun; Cao, Kaiming; Wang, Xiping

2007-10-19

Two putative Arabidopsis E group bZIP transcript factors, AtbZIP34 and AtbZIP61, are nuclear-localized and their transcriptional activation domain is in their N-terminal region. By searching GenBank, we found other eight plant homologues of AtbZIP34 and AtbZIP61. All of them have a proline residue in the third heptad of zipper region. Yeast two-hybrid assay and EMSA showed that AtbZIP34 and AtbZIP61 could not form homodimer while their mutant forms, AtbZIP34m and AtbZIP61m, which the proline residue was replaced by an alanine residue in the zipper region, could form homodimer and bind G-box element. These results suggest that the conserved proline residue interferes with the homodimer formation. However, both AtbZIP34 and AtbZIP61 could form heterodimers with members of I group and S group transcription factors in which some members involved in vascular development. So we speculate that AtbZIP34 and AtbZIP61 may participate in plant development via interacting with other group bZIP transcription factors.

Soybean extracts increase cell surface ZIP4 abundance and cellular zinc levels: a potential novel strategy to enhance zinc absorption by ZIP4 targeting.

PubMed

Hashimoto, Ayako; Ohkura, Katsuma; Takahashi, Masakazu; Kizu, Kumiko; Narita, Hiroshi; Enomoto, Shuichi; Miyamae, Yusaku; Masuda, Seiji; Nagao, Masaya; Irie, Kazuhiro; Ohigashi, Hajime; Andrews, Glen K; Kambe, Taiho

2015-12-01

Dietary zinc deficiency puts human health at risk, so we explored strategies for enhancing zinc absorption. In the small intestine, the zinc transporter ZIP4 functions as an essential component of zinc absorption. Overexpression of ZIP4 protein increases zinc uptake and thereby cellular zinc levels, suggesting that food components with the ability to increase ZIP4 could potentially enhance zinc absorption via the intestine. In the present study, we used mouse Hepa cells, which regulate mouse Zip4 (mZip4) in a manner indistinguishable from that in intestinal enterocytes, to screen for suitable food components that can increase the abundance of ZIP4. Using this ZIP4-targeting strategy, two such soybean extracts were identified that were specifically able to decrease mZip4 endocytosis in response to zinc. These soybean extracts also effectively increased the abundance of apically localized mZip4 in transfected polarized Caco2 and Madin-Darby canine kidney cells and, moreover, two apically localized mZip4 acrodermatitis enteropathica mutants. Soybean components were purified from one extract and soyasaponin Bb was identified as an active component that increased both mZip4 protein abundance and zinc levels in Hepa cells. Finally, we confirmed that soyasaponin Bb is capable of enhancing cell surface endogenous human ZIP4 in human cells. Our results suggest that ZIP4 targeting may represent a new strategy to improve zinc absorption in humans. © 2015 Authors; published by Portland Press Limited.

SlbZIP38, a Tomato bZIP Family Gene Downregulated by Abscisic Acid, Is a Negative Regulator of Drought and Salt Stress Tolerance

PubMed Central

Pan, Yanglu; Hu, Xin; Li, Chunyan; Xu, Xing; Su, Chenggang; Li, Jinhua; Song, Hongyuan; Zhang, Xingguo; Pan, Yu

2017-01-01

The basic leucine zipper (bZIP) transcription factors have crucial roles in plant stress responses. In this study, the bZIP family gene SlbZIP38 (GenBank accession No: XM004239373) was isolated from a tomato (Solanum lycopersicum cv. Ailsa Craig) mature leaf cDNA library. The DNA sequence of SlbZIP38 encodes a protein of 484 amino acids, including a highly conserved bZIP DNA-binding domain in the C-terminal region. We found that SlbZIP38 was differentially expressed in various organs of the tomato plant and was downregulated by drought, salt stress, and abscisic acid (ABA). However, overexpression of SlbZIP38 significantly decreased drought and salt stress tolerance in tomatoes (Ailsa Craig). The findings that SlbZIP38 overexpression reduced the chlorophyll and free proline content in leaves but increased the malondialdehyde content may explain the reduced drought and salt tolerance observed in these lines. These results suggest that SlbZIP38 is a negative regulator of drought and salt resistance that acts by modulating ABA signaling. PMID:29261143

Structure and function of homodomain-leucine zipper (HD-Zip) proteins.

PubMed

Elhiti, Mohamed; Stasolla, Claudio

2009-02-01

Homeodomain-leucine zipper (HD-Zip) proteins are transcription factors unique to plants and are encoded by more than 25 genes in Arabidopsis thaliana. Based on sequence analyses these proteins have been classified into four distinct groups: HD-Zip I-IV. HD-Zip proteins are characterized by the presence of two functional domains; a homeodomain (HD) responsible for DNA binding and a leucine zipper domain (Zip) located immediately C-terminal to the homeodomain and involved in protein-protein interaction. Despite sequence similarities HD-ZIP proteins participate in a variety of processes during plant growth and development. HD-Zip I proteins are generally involved in responses related to abiotic stress, abscisic acid (ABA), blue light, de-etiolation and embryogenesis. HD-Zip II proteins participate in light response, shade avoidance and auxin signalling. Members of the third group (HD-Zip III) control embryogenesis, leaf polarity, lateral organ initiation and meristem function. HD-Zip IV proteins play significant roles during anthocyanin accumulation, differentiation of epidermal cells, trichome formation and root development.

The ZIP family zinc transporters support the virulence of Cryptococcus neoformans

PubMed Central

Do, Eunsoo; Hu, Guanggan; Caza, Mélissa; Kronstad, James W.; Jung, Won Hee

2016-01-01

Zinc is an essential element in living organisms and a cofactor for various metalloproteins. To disseminate and survive, a pathogenic microbe must obtain zinc from the host, which is an environment with extremely limited zinc availability. In this study, we investigated the roles of the ZIP family zinc transporters Zip1 and Zip2 in the human pathogenic fungus Cryptococcus neoformans. Zip1 and Zip2 are homologous to Zrt1 and Zrt2 of the model fungus, Saccharomyces cerevisiae, respectively. We found that the expression of ZIP1 was regulated by the zinc concentration in the environment. Furthermore, the mutant lacking ZIP1 displayed a severe growth defect under zinc-limited conditions, while the mutant lacking ZIP2 displayed normal growth. Inductively coupled plasma–atomic emission spectroscopy analysis showed that the absence of Zip1 expression significantly reduced total cellular zinc levels relative to that in the wild type, while overexpression of Zip1 was associated with increased cellular zinc levels. These findings suggested that Zip1 plays roles in zinc uptake in C. neoformans. We also constructed a Zip1-FLAG fusion protein and found, by immunofluorescence, not only that the protein was localized to the periphery implying it is a membrane transporter, but also that the protein was N-glycosylated. Furthermore, the mutant lacking ZIP1 showed attenuated virulence in a murine inhalation model of cryptococcosis and reduced survival within murine macrophages. Overall, our data suggest that Zip1 plays essential roles in zinc transport and the virulence of C. neoformans. PMID:27118799

Quasiopen inflation

NASA Astrophysics Data System (ADS)

García-Bellido, Juan; Garriga, Jaume; Montes, Xavier

1998-04-01

We show that a large class of two-field models of single-bubble open inflation does not lead to infinite open universes, as was previously thought, but to an ensemble of very large but finite inflating ``islands.'' The reason is that the quantum tunneling responsible for the nucleation of the bubble does not occur simultaneously along both field directions and equal-time hypersurfaces in the open universe are not synchronized with equal-density or fixed-field hypersurfaces. The most probable tunneling trajectory corresponds to a zero value of the inflaton field; large values, necessary for the second period of inflation inside the bubble, only arise as localized fluctuations. The interior of each nucleated bubble will contain an infinite number of such inflating regions of comoving size of order γ-1, where γ is the supercurvature eigenvalue, which depends on the parameters of the model. Each one of these islands will be a quasi-open universe. Since the volume of the hyperboloid is infinite, inflating islands with all possible values of the field at their center will be realized inside of a single bubble. We may happen to live in one of those patches of comoving size d<~γ-1, where the universe appears to be open. In particular, we consider the ``supernatural'' model proposed by Linde and Mezhlumian. There, an approximate U(1) symmetry is broken by a tunneling field in a first order phase transition, and slow-roll inflation inside the nucleated bubble is driven by the pseudo Goldstone field. We find that the excitations of the pseudo Goldstone field produced by the nucleation and subsequent expansion of the bubble place severe constraints on this model. We also discuss the coupled and uncoupled two-field models.

In vivo binding of hot pepper bZIP transcription factor CabZIP1 to the G-box region of pathogenesis-related protein 1 promoter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Boo-Ja; Park, Chang-Jin; Kim, Sung-Kyu

2006-05-26

We find that salicylic acid and ethephon treatment in hot pepper increases the expression of a putative basic/leucine zipper (bZIP) transcription factor gene, CabZIP1. CabZIP1 mRNA is expressed ubiquitously in various organs. The green fluorescent protein-fused transcription factor, CabZIP1::GFP, can be specifically localized to the nucleus, an action that is consistent with the presence of a nuclear localization signal in its protein sequence. Transient overexpression of the CabZIP1 transcription factor results in an increase in PR-1 transcripts level in Nicotiana benthamiana leaves. Using chromatin immunoprecipitation, we demonstrate that CabZIP1 binds to the G-box elements in native promoter of the hotmore » pepper pathogenesis-related protein 1 (CaPR-1) gene in vivo. Taken together, our results suggest that CabZIP1 plays a role as a transcriptional regulator of the CaPR-1 gene.« less

Functional Analysis of Maize Silk-Specific ZmbZIP25 Promoter.

PubMed

Li, Wanying; Yu, Dan; Yu, Jingjuan; Zhu, Dengyun; Zhao, Qian

2018-03-12

ZmbZIP25 ( Zea mays bZIP (basic leucine zipper) transcription factor 25) is a function-unknown protein that belongs to the D group of the bZIP transcription factor family. RNA-seq data showed that the expression of ZmbZIP25 was tissue-specific in maize silks, and this specificity was confirmed by RT-PCR (reverse transcription-polymerase chain reaction). In situ RNA hybridization showed that ZmbZIP25 was expressed exclusively in the xylem of maize silks. A 5' RACE (rapid amplification of cDNA ends) assay identified an adenine residue as the transcription start site of the ZmbZIP25 gene. To characterize this silk-specific promoter, we isolated and analyzed a 2450 bp (from -2083 to +367) and a 2600 bp sequence of ZmbZIP25 (from -2083 to +517, the transcription start site was denoted +1). Stable expression assays in Arabidopsis showed that the expression of the reporter gene GUS driven by the 2450 bp ZmbZIP25 5'-flanking fragment occurred exclusively in the papillae of Arabidopsis stigmas. Furthermore, transient expression assays in maize indicated that GUS and GFP expression driven by the 2450 bp ZmbZIP25 5'-flanking sequences occurred only in maize silks and not in other tissues. However, no GUS or GFP expression was driven by the 2600 bp ZmbZIP25 5'-flanking sequences in either stable or transient expression assays. A series of deletion analyses of the 2450 bp ZmbZIP25 5'-flanking sequence was performed in transgenic Arabidopsis plants, and probable elements prediction analysis revealed the possible presence of negative regulatory elements within the 161 bp region from -1117 to -957 that were responsible for the specificity of the ZmbZIP25 5'-flanking sequence.

Functional Analysis of Maize Silk-Specific ZmbZIP25 Promoter

PubMed Central

Li, Wanying; Yu, Dan; Yu, Jingjuan; Zhu, Dengyun; Zhao, Qian

2018-01-01

ZmbZIP25 (Zea mays bZIP (basic leucine zipper) transcription factor 25) is a function-unknown protein that belongs to the D group of the bZIP transcription factor family. RNA-seq data showed that the expression of ZmbZIP25 was tissue-specific in maize silks, and this specificity was confirmed by RT-PCR (reverse transcription-polymerase chain reaction). In situ RNA hybridization showed that ZmbZIP25 was expressed exclusively in the xylem of maize silks. A 5′ RACE (rapid amplification of cDNA ends) assay identified an adenine residue as the transcription start site of the ZmbZIP25 gene. To characterize this silk-specific promoter, we isolated and analyzed a 2450 bp (from −2083 to +367) and a 2600 bp sequence of ZmbZIP25 (from −2083 to +517, the transcription start site was denoted +1). Stable expression assays in Arabidopsis showed that the expression of the reporter gene GUS driven by the 2450 bp ZmbZIP25 5′-flanking fragment occurred exclusively in the papillae of Arabidopsis stigmas. Furthermore, transient expression assays in maize indicated that GUS and GFP expression driven by the 2450 bp ZmbZIP25 5′-flanking sequences occurred only in maize silks and not in other tissues. However, no GUS or GFP expression was driven by the 2600 bp ZmbZIP25 5′-flanking sequences in either stable or transient expression assays. A series of deletion analyses of the 2450 bp ZmbZIP25 5′-flanking sequence was performed in transgenic Arabidopsis plants, and probable elements prediction analysis revealed the possible presence of negative regulatory elements within the 161 bp region from −1117 to −957 that were responsible for the specificity of the ZmbZIP25 5′-flanking sequence. PMID:29534529

Bioinformatic Analyses of Subgroup-A Members of the Wheat bZIP Transcription Factor Family and Functional Identification of TabZIP174 Involved in Drought Stress Response

PubMed Central

Li, Xueyin; Feng, Biane; Zhang, Fengjie; Tang, Yimiao; Zhang, Liping; Ma, Lingjian; Zhao, Changping; Gao, Shiqing

2016-01-01

Extensive studies in Arabidopsis and rice have demonstrated that Subgroup-A members of the bZIP transcription factor family play important roles in plant responses to multiple abiotic stresses. Although common wheat (Triticum aestivum) is one of the most widely cultivated and consumed food crops in the world, there are limited investigations into Subgroup A of the bZIP family in wheat. In this study, we performed bioinformatic analyses of the 41 Subgroup-A members of the wheat bZIP family. Phylogenetic and conserved motif analyses showed that most of the Subgroup-A bZIP proteins involved in abiotic stress responses of wheat, Arabidopsis, and rice clustered in Clade A1 of the phylogenetic tree, and shared a majority of conserved motifs, suggesting the potential importance of Clade-A1 members in abiotic stress responses. Gene structure analysis showed that TabZIP genes with close phylogenetic relationships tended to possess similar exon–intron compositions, and the positions of introns in the hinge regions of the bZIP domains were highly conserved, whereas introns in the leucine zipper regions were at variable positions. Additionally, eleven groups of homologs and two groups of tandem paralogs were also identified in Subgroup A of the wheat bZIP family. Expression profiling analysis indicated that most Subgroup-A TabZIP genes were responsive to abscisic acid and various abiotic stress treatments. TabZIP27, TabZIP74, TabZIP138, and TabZIP174 proteins were localized in the nucleus of wheat protoplasts, whereas TabZIP9-GFP fusion protein was simultaneously present in the nucleus, cytoplasm, and cell membrane. Transgenic Arabidopsis overexpressing TabZIP174 displayed increased seed germination rates and primary root lengths under drought treatments. Overexpression of TabZIP174 in transgenic Arabidopsis conferred enhanced drought tolerance, and transgenic plants exhibited lower water loss rates, higher survival rates, higher proline, soluble sugar, and leaf chlorophyll

Simulation on Poisson and negative binomial models of count road accident modeling

NASA Astrophysics Data System (ADS)

Sapuan, M. S.; Razali, A. M.; Zamzuri, Z. H.; Ibrahim, K.

2016-11-01

Accident count data have often been shown to have overdispersion. On the other hand, the data might contain zero count (excess zeros). The simulation study was conducted to create a scenarios which an accident happen in T-junction with the assumption the dependent variables of generated data follows certain distribution namely Poisson and negative binomial distribution with different sample size of n=30 to n=500. The study objective was accomplished by fitting Poisson regression, negative binomial regression and Hurdle negative binomial model to the simulated data. The model validation was compared and the simulation result shows for each different sample size, not all model fit the data nicely even though the data generated from its own distribution especially when the sample size is larger. Furthermore, the larger sample size indicates that more zeros accident count in the dataset.

Genome-Wide Analysis of bZIP-Encoding Genes in Maize

PubMed Central

Wei, Kaifa; Chen, Juan; Wang, Yanmei; Chen, Yanhui; Chen, Shaoxiang; Lin, Yina; Pan, Si; Zhong, Xiaojun; Xie, Daoxin

2012-01-01

In plants, basic leucine zipper (bZIP) proteins regulate numerous biological processes such as seed maturation, flower and vascular development, stress signalling and pathogen defence. We have carried out a genome-wide identification and analysis of 125 bZIP genes that exist in the maize genome, encoding 170 distinct bZIP proteins. This family can be divided into 11 groups according to the phylogenetic relationship among the maize bZIP proteins and those in Arabidopsis and rice. Six kinds of intron patterns (a–f) within the basic and hinge regions are defined. The additional conserved motifs have been identified and present the group specificity. Detailed three-dimensional structure analysis has been done to display the sequence conservation and potential distribution of the bZIP domain. Further, we predict the DNA-binding pattern and the dimerization property on the basis of the characteristic features in the basic and hinge regions and the leucine zipper, respectively, which supports our classification greatly and helps to classify 26 distinct subfamilies. The chromosome distribution and the genetic analysis reveal that 58 ZmbZIP genes are located in the segmental duplicate regions in the maize genome, suggesting that the segment chromosomal duplications contribute greatly to the expansion of the maize bZIP family. Across the 60 different developmental stages of 11 organs, three apparent clusters formed represent three kinds of different expression patterns among the ZmbZIP gene family in maize development. A similar but slightly different expression pattern of bZIPs in two inbred lines displays that 22 detected ZmbZIP genes might be involved in drought stress. Thirteen pairs and 143 pairs of ZmbZIP genes show strongly negative and positive correlations in the four distinct fungal infections, respectively, based on the expression profile and Pearson's correlation coefficient analysis. PMID:23103471

Non-linear properties of metallic cellular materials with a negative Poisson's ratio

NASA Technical Reports Server (NTRS)

Choi, J. B.; Lakes, R. S.

1992-01-01

Negative Poisson's ratio copper foam was prepared and characterized experimentally. The transformation into re-entrant foam was accomplished by applying sequential permanent compressions above the yield point to achieve a triaxial compression. The Poisson's ratio of the re-entrant foam depended on strain and attained a relative minimum at strains near zero. Poisson's ratio as small as -0.8 was achieved. The strain dependence of properties occurred over a narrower range of strain than in the polymer foams studied earlier. Annealing of the foam resulted in a slightly greater magnitude of negative Poisson's ratio and greater toughness at the expense of a decrease in the Young's modulus.

Efficiency optimization of a fast Poisson solver in beam dynamics simulation

NASA Astrophysics Data System (ADS)

Zheng, Dawei; Pöplau, Gisela; van Rienen, Ursula

2016-01-01

Calculating the solution of Poisson's equation relating to space charge force is still the major time consumption in beam dynamics simulations and calls for further improvement. In this paper, we summarize a classical fast Poisson solver in beam dynamics simulations: the integrated Green's function method. We introduce three optimization steps of the classical Poisson solver routine: using the reduced integrated Green's function instead of the integrated Green's function; using the discrete cosine transform instead of discrete Fourier transform for the Green's function; using a novel fast convolution routine instead of an explicitly zero-padded convolution. The new Poisson solver routine preserves the advantages of fast computation and high accuracy. This provides a fast routine for high performance calculation of the space charge effect in accelerators.

Overexpression of a wheat (Triticum aestivum L.) bZIP transcription factor gene, TabZIP6, decreased the freezing tolerance of transgenic Arabidopsis seedlings by down-regulating the expression of CBFs.

PubMed

Cai, Wangting; Yang, Yaling; Wang, Weiwei; Guo, Guangyan; Liu, Wei; Bi, Caili

2018-03-01

The basic leucine zipper (bZIP) proteins play important roles against abiotic stress in plants, including cold stress. However, most bZIPs involved in plant freezing tolerance are positive regulators. Only a few bZIPs function negatively in cold stress response. In this study, TabZIP6, a Group C bZIP transcription factor gene from common wheat (Triticum aestivum L.), was cloned and characterized. The transcript of TabZIP6 was strongly induced by cold treatment (4 °C). TabZIP6 is a nuclear-localized protein with transcriptional activation activity. Arabidopsis plants overexpressing TabZIP6 showed decreased tolerance to freezing stress. Microarray as well as quantitative real-time PCR (qRT-PCR) analysis showed that CBFs and some key COR genes, including COR47 and COR15B, were down-regulated by cold treatment in TabZIP6-overexpressing Arabidopsis lines. TabZIP6 was capable of binding to the G-box motif and the CBF1 and CBF3 promoters in yeast cells. A yeast two-hybrid assay revealed that TabZIP6, as well as the other two Group S bZIP proteins involved in cold stress tolerance in wheat, Wlip19 and TaOBF1, can form homodimers by themselves and heterodimers with each other. These results suggest that TabZIP6 may function negatively in the cold stress response by binding to the promoters of CBFs, and thereby decreasing the expression of downstream COR genes in TabZIP6-overexpressing Arabidopsis seedlings. Copyright © 2018. Published by Elsevier Masson SAS.

Zipping dielectric elastomer actuators: characterization, design and modeling

NASA Astrophysics Data System (ADS)

Maffli, L.; Rosset, S.; Shea, H. R.

2013-10-01

We report on miniature dielectric elastomer actuators (DEAs) operating in zipping mode with an analytical model that predicts their behavior. Electrostatic zipping is a well-known mechanism in silicon MEMS to obtain large deformations and forces at lower voltages than for parallel plate electrostatic actuation. We extend this concept to DEAs, which allows us to obtain much larger out-of-plane displacements compared to silicon thanks to the softness of the elastomer membrane. We study experimentally the effect of sidewall angles and elastomer prestretch on 2.3 mm diameter actuators with PDMS membranes. With 15° and 22.5° sidewall angles, the devices zip in a bistable manner down 300 μm to the bottom of the chambers. The highly tunable bistable behavior is controllable by both chamber geometry and membrane parameters. Other specific characteristics of zipping DEAs include well-controlled deflected shape, tunable displacement versus voltage characteristics to virtually any shape, including multi-stable modes, sealing of embedded holes or channels for valving action and the reduction of the operating voltage. These properties make zipping DEAs an excellent candidate for applications such as integrated microfluidics actuators or Braille displays.

The BRST complex of homological Poisson reduction

NASA Astrophysics Data System (ADS)

Müller-Lennert, Martin

2017-02-01

BRST complexes are differential graded Poisson algebras. They are associated with a coisotropic ideal J of a Poisson algebra P and provide a description of the Poisson algebra (P/J)^J as their cohomology in degree zero. Using the notion of stable equivalence introduced in Felder and Kazhdan (Contemporary Mathematics 610, Perspectives in representation theory, 2014), we prove that any two BRST complexes associated with the same coisotropic ideal are quasi-isomorphic in the case P = R[V] where V is a finite-dimensional symplectic vector space and the bracket on P is induced by the symplectic structure on V. As a corollary, the cohomology of the BRST complexes is canonically associated with the coisotropic ideal J in the symplectic case. We do not require any regularity assumptions on the constraints generating the ideal J. We finally quantize the BRST complex rigorously in the presence of infinitely many ghost variables and discuss the uniqueness of the quantization procedure.

Horizon feedback inflation

NASA Astrophysics Data System (ADS)

Fairbairn, Malcolm; Markkanen, Tommi; Rodriguez Roman, David

2018-04-01

We consider the effect of the Gibbons-Hawking radiation on the inflaton in the situation where it is coupled to a large number of spectator fields. We argue that this will lead to two important effects - a thermal contribution to the potential and a gradual change in parameters in the Lagrangian which results from thermodynamic and energy conservation arguments. We present a scenario of hilltop inflation where the field starts trapped at the origin before slowly experiencing a phase transition during which the field extremely slowly moves towards its zero temperature expectation value. We show that it is possible to obtain enough e-folds of expansion as well as the correct spectrum of perturbations without hugely fine-tuned parameters in the potential (albeit with many spectator fields). We also comment on how initial conditions for inflation can arise naturally in this situation.

ZIP4 silencing improves bone loss in pancreatic cancer

PubMed Central

Yang, Jingxuan; Ding, Hao; LeBrun, Drake; Ding, Kai; Houchen, Courtney W.; Postier, Russell G.; Ambrose, Catherine G.; Li, Zhaoshen; Bi, Xiaohong; Li, Min

2015-01-01

Metabolic bone disorders are associated with several types of human cancers. Pancreatic cancer patients usually suffer from severe nutrition deficiency, muscle wasting, and loss of bone mass. We have previously found that silencing of a zinc transporter ZIP4 prolongs the survival and reduces the severity of the cachexia in vivo. However, the role of ZIP4 in the pancreatic cancer related bone loss remains unknown. In this study we investigated the effect of ZIP4 knockdown on the bone structure, composition and mechanical properties of femurs in an orthotopic xenograft mouse model. Our data showed that silencing of ZIP4 resulted in increased bone tissue mineral density, decreased bone crystallinity and restoration of bone strength through the RANK/RANKL pathway. The results further support the impact of ZIP4 on the progression of pancreatic cancer, and suggest its potential significance as a therapeutic target for treating patients with such devastating disease and cancer related disorders. PMID:26305676

Novel Phenotype Issues Raised in Cross-National Epidemiological Research on Drug Dependence

PubMed Central

Anthony, James C.

2010-01-01

Stage-transition models based on the American Diagnostic and Statistical Manual (DSM) generally are applied in epidemiology and genetics research on drug dependence syndromes associated with cannabis, cocaine, and other internationally regulated drugs (IRD). Difficulties with DSM stage-transition models have surfaced during cross-national research intended to provide a truly global perspective, such as the work of the World Mental Health Surveys (WMHS) Consortium. Alternative simpler dependence-related phenotypes are possible, including population-level count process models for steps early and before coalescence of clinical features into a coherent syndrome (e.g., zero-inflated Poisson regression). Selected findings are reviewed, based on ZIP modeling of alcohol, tobacco, and IRD count processes, with an illustration that may stimulate new research on genetic susceptibility traits. The annual National Surveys on Drug Use and Health can be readily modified for this purpose, along the lines of a truly anonymous research approach that can help make NSDUH-type cross-national epidemiological surveys more useful in the context of subsequent genome wide association (GWAS) research and post-GWAS investigations with a truly global health perspective. PMID:20201862

Genericness of inflation in isotropic loop quantum cosmology.

PubMed

Date, Ghanashyam; Hossain, Golam Mortuza

2005-01-14

Nonperturbative corrections from loop quantum cosmology (LQC) to the scalar matter sector are already known to imply inflation. We prove that the LQC modified scalar field generates exponential inflation in the small scale factor regime, for all positive definite potentials, independent of initial conditions and independent of ambiguity parameters. For positive semidefinite potentials it is always possible to choose, without fine-tuning, a value of one of the ambiguity parameters such that exponential inflation results, provided zeros of the potential are approached at most as a power law in the scale factor. In conjunction with the generic occurrence of bounce at small volumes, particle horizon is absent, thus eliminating the horizon problem of the standard big bang model.

Three-part joint modeling methods for complex functional data mixed with zero-and-one-inflated proportions and zero-inflated continuous outcomes with skewness.

PubMed

Li, Haocheng; Staudenmayer, John; Wang, Tianying; Keadle, Sarah Kozey; Carroll, Raymond J

2018-02-20

We take a functional data approach to longitudinal studies with complex bivariate outcomes. This work is motivated by data from a physical activity study that measured 2 responses over time in 5-minute intervals. One response is the proportion of time active in each interval, a continuous proportions with excess zeros and ones. The other response, energy expenditure rate in the interval, is a continuous variable with excess zeros and skewness. This outcome is complex because there are 3 possible activity patterns in each interval (inactive, partially active, and completely active), and those patterns, which are observed, induce both nonrandom and random associations between the responses. More specifically, the inactive pattern requires a zero value in both the proportion for active behavior and the energy expenditure rate; a partially active pattern means that the proportion of activity is strictly between zero and one and that the energy expenditure rate is greater than zero and likely to be moderate, and the completely active pattern means that the proportion of activity is exactly one, and the energy expenditure rate is greater than zero and likely to be higher. To address these challenges, we propose a 3-part functional data joint modeling approach. The first part is a continuation-ratio model to reorder the ordinal valued 3 activity patterns. The second part models the proportions when they are in interval (0,1). The last component specifies the skewed continuous energy expenditure rate with Box-Cox transformations when they are greater than zero. In this 3-part model, the regression structures are specified as smooth curves measured at various time points with random effects that have a correlation structure. The smoothed random curves for each variable are summarized using a few important principal components, and the association of the 3 longitudinal components is modeled through the association of the principal component scores. The difficulties in

The bZIP transcription factor PfZipA regulates secondary metabolism and oxidative stress response in the plant endophytic fungus Pestalotiopsis fici.

PubMed

Wang, Xiuna; Wu, Fan; Liu, Ling; Liu, Xingzhong; Che, Yongsheng; Keller, Nancy P; Guo, Liyun; Yin, Wen-Bing

2015-08-01

The bZIP transcription factors are conserved in all eukaryotes and play critical roles in organismal responses to environmental challenges. In filamentous fungi, several lines of evidence indicate that secondary metabolism (SM) is associated with oxidative stress mediated by bZIP proteins. Here we uncover a connection with a bZIP protein and oxidative stress induction of SM in the plant endophytic fungus Pestalotiopsis fici. A homology search of the P. fici genome with the bZIP protein RsmA, involved in SM and the oxidative stress response in Aspergillus nidulans, identified PfZipA. Deletion of PfzipA resulted in a strain that displayed resistant to the oxidative reagents tert-butylhydroperoxide (tBOOH), diamide, and menadione sodium bisulfite (MSB), but increased sensitivity to H2O2 as compared to wild type (WT). Secondary metabolite production presented a complex pattern dependent on PfzipA and oxidative reagents. Without oxidative treatment, the ΔPfzipA strain produced less isosulochrin and ficipyroneA than WT; addition of tBOOH further decreased production of iso-A82775C and pestaloficiol M in ΔPfzipA; diamide treatment resulted in equivalent production of isosulochrin and ficipyroneA in the two strains; MSB treatment further decreased production of RES1214-1 and iso-A82775C but increased pestaloficiol M production in the mutant; and H2O2 treatment resulted in enhanced production of isosulochrin, RES1214-1 and pestheic acid but decreased ficipyroneA and pestaloficiol M in ΔPfzipA compared to WT. Our results suggest that PfZipA regulation of SM is modified by oxidative stress pathways and provide insights into a possible role of PfZipA in mediating SM synthesis in the endophytic lifestyle of P. fici. Copyright © 2015 Elsevier Inc. All rights reserved.

Structural insights of ZIP4 extracellular domain critical for optimal zinc transport

NASA Astrophysics Data System (ADS)

Zhang, Tuo; Sui, Dexin; Hu, Jian

2016-06-01

The ZIP zinc transporter family is responsible for zinc uptake from the extracellular milieu or intracellular vesicles. The LIV-1 subfamily, containing nine out of the 14 human ZIP proteins, is featured with a large extracellular domain (ECD). The critical role of the ECD is manifested by disease-causing mutations on ZIP4, a representative LIV-1 protein. Here we report the first crystal structure of a mammalian ZIP4-ECD, which reveals two structurally independent subdomains and an unprecedented dimer centred at the signature PAL motif. Structure-guided mutagenesis, cell-based zinc uptake assays and mapping of the disease-causing mutations indicate that the two subdomains play pivotal but distinct roles and that the bridging region connecting them is particularly important for ZIP4 function. These findings lead to working hypotheses on how ZIP4-ECD exerts critical functions in zinc transport. The conserved dimeric architecture in ZIP4-ECD is also demonstrated to be a common structural feature among the LIV-1 proteins.

Poisson-Like Spiking in Circuits with Probabilistic Synapses

PubMed Central

Moreno-Bote, Rubén

2014-01-01

Neuronal activity in cortex is variable both spontaneously and during stimulation, and it has the remarkable property that it is Poisson-like over broad ranges of firing rates covering from virtually zero to hundreds of spikes per second. The mechanisms underlying cortical-like spiking variability over such a broad continuum of rates are currently unknown. We show that neuronal networks endowed with probabilistic synaptic transmission, a well-documented source of variability in cortex, robustly generate Poisson-like variability over several orders of magnitude in their firing rate without fine-tuning of the network parameters. Other sources of variability, such as random synaptic delays or spike generation jittering, do not lead to Poisson-like variability at high rates because they cannot be sufficiently amplified by recurrent neuronal networks. We also show that probabilistic synapses predict Fano factor constancy of synaptic conductances. Our results suggest that synaptic noise is a robust and sufficient mechanism for the type of variability found in cortex. PMID:25032705

Evolutionary Descent of Prion Genes from the ZIP Family of Metal Ion Transporters

PubMed Central

Schmitt-Ulms, Gerold; Ehsani, Sepehr; Watts, Joel C.; Westaway, David; Wille, Holger

2009-01-01

In the more than twenty years since its discovery, both the phylogenetic origin and cellular function of the prion protein (PrP) have remained enigmatic. Insights into a possible function of PrP may be obtained through the characterization of its molecular neighborhood in cells. Quantitative interactome data demonstrated the spatial proximity of two metal ion transporters of the ZIP family, ZIP6 and ZIP10, to mammalian prion proteins in vivo. A subsequent bioinformatic analysis revealed the unexpected presence of a PrP-like amino acid sequence within the N-terminal, extracellular domain of a distinct sub-branch of the ZIP protein family that includes ZIP5, ZIP6 and ZIP10. Additional structural threading and orthologous sequence alignment analyses argued that the prion gene family is phylogenetically derived from a ZIP-like ancestral molecule. The level of sequence homology and the presence of prion protein genes in most chordate species place the split from the ZIP-like ancestor gene at the base of the chordate lineage. This relationship explains structural and functional features found within mammalian prion proteins as elements of an ancient involvement in the transmembrane transport of divalent cations. The phylogenetic and spatial connection to ZIP proteins is expected to open new avenues of research to elucidate the biology of the prion protein in health and disease. PMID:19784368

Using ZIP Code Business Patterns Data to Measure Alcohol Outlet Density

PubMed Central

Matthews, Stephen A.; McCarthy, John D.; Rafail, Patrick S.

2014-01-01

Some states maintain high-quality alcohol outlet databases but quality varies by state, making comprehensive comparative analysis across US communities difficult. This study assesses the adequacy of using ZIP Code Business Patterns (ZIP-BP) data on establishments as estimates of the number of alcohol outlets by ZIP code. Specifically we compare ZIP-BP alcohol outlet counts with high-quality data from state and local records surrounding 44 college campus communities across 10 states plus the District of Columbia. Results show that a composite measure is strongly correlated (R=0.89) with counts of alcohol outlets generated from official state records. Analyses based on Generalized Estimation Equation models show that community and contextual factors have little impact on the concordance between the two data sources. There are also minimal inter-state differences in the level of agreement. To validate the use of a convenient secondary data set (ZIP-BP) it is important to have a high correlation with the more complex, high quality and more costly data product (i.e., datasets based on the acquisition and geocoding of state and local records) and then to clearly demonstrate that the discrepancy between the two to be unrelated to relevant explanatory variables. Thus our overall findings support the adequacy of using a conveniently available data set (ZIP-BP data) to estimate alcohol outlet densities in ZIP code areas in future research. PMID:21411233

Zeroth Poisson Homology, Foliated Cohomology and Perfect Poisson Manifolds

NASA Astrophysics Data System (ADS)

Martínez-Torres, David; Miranda, Eva

2018-01-01

We prove that, for compact regular Poisson manifolds, the zeroth homology group is isomorphic to the top foliated cohomology group, and we give some applications. In particular, we show that, for regular unimodular Poisson manifolds, top Poisson and foliated cohomology groups are isomorphic. Inspired by the symplectic setting, we define what a perfect Poisson manifold is. We use these Poisson homology computations to provide families of perfect Poisson manifolds.

Expression of a grape (Vitis vinifera) bZIP transcription factor, VlbZIP36, in Arabidopsis thaliana confers tolerance of drought stress during seed germination and seedling establishment.

PubMed

Tu, Mingxing; Wang, Xianhang; Feng, Tongying; Sun, Xiaomeng; Wang, Yaqiong; Huang, Li; Gao, Min; Wang, Yuejin; Wang, Xiping

2016-11-01

Drought is one of the most serious factors that limit agricultural productivity and there is considerable interest in understanding the molecular bases of drought responses and their regulation. While numbers of basic leucine zipper (bZIP) transcription factors (TFs) are known to play key roles in response of plants to various abiotic stresses, only a few group K bZIP TFs have been functionally characterized in the context of stress signaling. In this study, we characterized the expression of the grape (Vitis vinifera) group K bZIP gene, VlbZIP36, and found evidence for its involvement in response to drought and the stress-associated phytohormone abscisic acid (ABA). Transgenic Arabidopsis thaliana lines over-expressing VlbZIP36 under the control of a constitutive promoter showed enhanced dehydration tolerance during the seed germination stage, as well as in the seedling and mature plant stages. The results indicated that VlbZIP36 plays a role in drought tolerance by improving the water status, through limiting water loss, and mitigating cellular damage. The latter was evidenced by reduced cell death, lower electrolyte leakage in the transgenic plants, as well as by increased activities of antioxidant enzymes. We concluded that VlbZIP36 enhances drought tolerance through the transcriptional regulation of ABA-/stress-related genes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Recovery from temporary endoplasmic reticulum stress in plants relies on the tissue-specific and largely independent roles of bZIP28 and bZIP60, as well as an antagonizing function of BAX-Inhibitor 1 upon the pro-adaptive signaling mediated by bZIP28.

PubMed

Ruberti, Cristina; Lai, YaShiuan; Brandizzi, Federica

2018-01-01

The unfolded protein response (UPR) is an ancient signaling pathway that commits to life-or-death outcomes in response to proteotoxic stress in the endoplasmic reticulum (ER). In plants, the membrane-tethered transcription factor bZIP28 and the ribonuclease-kinase IRE1 along with its splicing target, bZIP60, govern the two cytoprotective UPR signaling pathways known to date. The conserved ER membrane-associated BAX inhibitor 1 (BI1) modulates ER stress-induced programmed cell death through yet-unknown mechanisms. Despite the significance of the UPR for cell homeostasis, in plants the regulatory circuitry underlying ER stress resolution is still largely unmapped. To gain insights into the coordination of plant UPR strategies, we analyzed the functional relationship of the UPR modulators through the analysis of single and higher order mutants of IRE1, bZIP60, bZIP28 and BI1 in experimental conditions causing either temporary or chronic ER stress. We established a functional duality of bZIP28 and bZIP60, as they exert partially independent tissue-specific roles in recovery from ER stress, but redundantly actuate survival strategies in chronic ER stress. We also discovered that BI1 attenuates the pro-survival function of bZIP28 in ER stress resolution and, differently to animal cells, it does not temper the ribonuclease activity of inositol-requiring enzyme 1 (IRE1) under temporary ER stress. Together these findings reveal a functional independence of bZIP28 and bZIP60 in plant UPR, and identify an antagonizing role of BI1 in the pro-adaptive signaling mediated by bZIP28, bringing to light the distinctive complexity of the unfolded protein response (UPR) in plants. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Molecular pathogenesis of Spondylocheirodysplastic Ehlers-Danlos syndrome caused by mutant ZIP13 proteins

PubMed Central

Bin, Bum-Ho; Hojyo, Shintaro; Hosaka, Toshiaki; Bhin, Jinhyuk; Kano, Hiroki; Miyai, Tomohiro; Ikeda, Mariko; Kimura-Someya, Tomomi; Shirouzu, Mikako; Cho, Eun-Gyung; Fukue, Kazuhisa; Kambe, Taiho; Ohashi, Wakana; Kim, Kyu-Han; Seo, Juyeon; Choi, Dong-Hwa; Nam, Yeon-Ju; Hwang, Daehee; Fukunaka, Ayako; Fujitani, Yoshio; Yokoyama, Shigeyuki; Superti-Furga, Andrea; Ikegawa, Shiro; Lee, Tae Ryong; Fukada, Toshiyuki

2014-01-01

The zinc transporter protein ZIP13 plays critical roles in bone, tooth, and connective tissue development, and its dysfunction is responsible for the spondylocheirodysplastic form of Ehlers-Danlos syndrome (SCD-EDS, OMIM 612350). Here, we report the molecular pathogenic mechanism of SCD-EDS caused by two different mutant ZIP13 proteins found in human patients: ZIP13G64D, in which Gly at amino acid position 64 is replaced by Asp, and ZIP13ΔFLA, which contains a deletion of Phe-Leu-Ala. We demonstrated that both the ZIP13G64D and ZIP13ΔFLA protein levels are decreased by degradation via the valosin-containing protein (VCP)-linked ubiquitin proteasome pathway. The inhibition of degradation pathways rescued the protein expression levels, resulting in improved intracellular Zn homeostasis. Our findings uncover the pathogenic mechanisms elicited by mutant ZIP13 proteins. Further elucidation of these degradation processes may lead to novel therapeutic targets for SCD-EDS. PMID:25007800

HMO market penetration and hospital cost inflation in California.

PubMed

Robinson, J C

1991-11-20

OBJECTIVE--Health maintenance organizations (HMOs) have stimulated price competition in California hospital markets since 1983, when the state legislature eliminated barriers to selective contracting by conventional health insurance plans. This study measures the impact of HMO-induced price competition on the rate of inflation in average cost per admission for 298 private, non-HMO hospitals between 1982 and 1988. DATA--HMO market penetration was calculated using discharge abstract data on insurance coverage, ZIP code of residence, and hospital of choice for 3.35 million patients in 1983 and 3.41 million patients in 1988. Data on hospital characteristics were obtained from the American Hospital Association and other sources. -HMO coverage grew from an average of 8.3% of all admissions in local hospital markets in 1983 to 17.0% of all admissions in 1988. The average rate of growth in costs per admission between 1982 and 1988 was 9.4% lower in markets with relatively high HMO penetration compared with markets with relatively low HMO penetration (95% confidence interval, 5.2 to 13.8). Cost savings for these 298 hospitals are estimated at $1.04 billion for 1988. CONCLUSION--Price competition between HMOs and conventional health insurers can significantly reduce hospital cost inflation if legislative barriers to selective contracting are removed. The impact of competition in California was modest, however, when evaluated in terms of the 74.5% average rate of California hospital cost inflation during these years.

Interplay of HD-Zip II and III transcription factors in auxin-regulated plant development.

PubMed

Turchi, L; Baima, S; Morelli, G; Ruberti, I

2015-08-01

The homeodomain-leucine zipper (HD-Zip) class of transcription factors is unique to plants. HD-Zip proteins bind to DNA exclusively as dimers recognizing dyad symmetric sequences and act as positive or negative regulators of gene expression. On the basis of sequence homology in the HD-Zip DNA-binding domain, HD-Zip proteins have been grouped into four families (HD-Zip I-IV). Each HD-Zip family can be further divided into subfamilies containing paralogous genes that have arisen through genome duplication. Remarkably, all the members of the HD-Zip IIγ and -δ clades are regulated by light quality changes that induce in the majority of the angiosperms the shade-avoidance response, a process regulated at multiple levels by auxin. Intriguingly, it has recently emerged that, apart from their function in shade avoidance, the HD-Zip IIγ and -δ transcription factors control several auxin-regulated developmental processes, including apical embryo patterning, lateral organ polarity, and gynoecium development, in a white-light environment. This review presents recent advances in our understanding of HD-Zip II protein function in plant development, with particular emphasis on the impact of loss-of-function HD-Zip II mutations on auxin distribution and response. The review also describes evidence demonstrating that HD-Zip IIγ and -δ genes are directly and positively regulated by HD-Zip III transcription factors, primary determinants of apical shoot development, known to control the expression of several auxin biosynthesis, transport, and response genes. Finally, the interplay between HD-Zip II and III transcription factors in embryo apical patterning and organ polarity is discussed. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The regulatory network of ThbZIP1 in response to abscisic acid treatment

PubMed Central

Ji, Xiaoyu; Liu, Guifeng; Liu, Yujia; Nie, Xianguang; Zheng, Lei; Wang, Yucheng

2015-01-01

Previously, a bZIP transcription factor from Tamarix hispida, ThbZIP1, was characterized: plants overexpressing ThbZIP1 displayed improved salt stress tolerance but were sensitive to abscisic acid (ABA). In the current study, we further characterized the regulatory network of ThbZIP1 and the mechanism of ABA sensitivity mediated by ThbZIP1. An ABF transcription factor from T. hispida, ThABF1, directly regulates the expression of ThbZIP1. Microarray analysis identified 1662 and 1609 genes that were respectively significantly upregulated or downregulated by ThbZIP1 when exposed to ABA. Gene ontology (GO) analysis showed that the processes including “response to stimulus,” “catalytic activity,” “binding function,” and “metabolic process” were highly altered in ThbZIP1 expressing plants exposed to ABA. The gene expression in ThbZIP1 transformed plants were compared between exposed to ABA and salt on the genome scale. Genes differentially regulated by both salt and ABA treatment only accounted for 9.75% of total differentially regulated genes. GO analysis showed that structural molecule activity, organelle part, membrane-enclosed lumen, reproduction, and reproductive process are enhanced by ABA but inhibited by salt stress. Conversely, immune system and multi-organism process were improved by salt but inhibited by ABA. Transcription regulator activity, enzyme regulator activity, and developmental process were significantly altered by ABA but were not affected by salt stress. Our study provides insights into how ThbZIP1 mediates ABA and salt stress response at the molecular level. PMID:25713576

Population trends, bend use relative to available habitat and within-river-bend habitat use of eight indicator species of Missouri and Lower Kansas River benthic fishes: 15 years after baseline assessment

USGS Publications Warehouse

Wildhaber, Mark L.; Yang, Wen-Hsi; Arab, Ali

2016-01-01

A baseline assessment of the Missouri River fish community and species-specific habitat use patterns conducted from 1996 to 1998 provided the first comprehensive analysis of Missouri River benthic fish population trends and habitat use in the Missouri and Lower Yellowstone rivers, exclusive of reservoirs, and provided the foundation for the present Pallid Sturgeon Population Assessment Program (PSPAP). Data used in such studies are frequently zero inflated. To address this issue, the zero-inflated Poisson (ZIP) model was applied. This follow-up study is based on PSPAP data collected up to 15 years later along with new understanding of how habitat characteristics among and within bends affect habitat use of fish species targeted by PSPAP, including pallid sturgeon. This work demonstrated that a large-scale, large-river, PSPAP-type monitoring program can be an effective tool for assessing population trends and habitat usage of large-river fish species. Using multiple gears, PSPAP was effective in monitoring shovelnose and pallid sturgeons, sicklefin, shoal and sturgeon chubs, sand shiner, blue sucker and sauger. For all species, the relationship between environmental variables and relative abundance differed, somewhat, among river segments suggesting the importance of the overall conditions of Upper and Middle Missouri River and Lower Missouri and Kansas rivers on the habitat usage patterns exhibited. Shoal and sicklefin chubs exhibited many similar habitat usage patterns; blue sucker and shovelnose sturgeon also shared similar responses. For pallid sturgeon, the primary focus of PSPAP, relative abundance tended to increase in Upper and Middle Missouri River paralleling stocking efforts, whereas no evidence of an increasing relative abundance was found in the Lower Missouri River despite stocking.

The transverse Poisson's ratio of composites.

NASA Technical Reports Server (NTRS)

Foye, R. L.

1972-01-01

An expression is developed that makes possible the prediction of Poisson's ratio for unidirectional composites with reference to any pair of orthogonal axes that are normal to the direction of the reinforcing fibers. This prediction appears to be a reasonable one in that it follows the trends of the finite element analysis and the bounding estimates, and has the correct limiting value for zero fiber content. It can only be expected to apply to composites containing stiff, circular, isotropic fibers bonded to a soft matrix material.

Using ZIP code business patterns data to measure alcohol outlet density.

PubMed

Matthews, Stephen A; McCarthy, John D; Rafail, Patrick S

2011-07-01

Some states maintain high-quality alcohol outlet databases but quality varies by state, making comprehensive comparative analysis across US communities difficult. This study assesses the adequacy of using ZIP Code Business Patterns (ZIP-BP) data on establishments as estimates of the number of alcohol outlets by ZIP code. Specifically we compare ZIP-BP alcohol outlet counts with high-quality data from state and local records surrounding 44 college campus communities across 10 states plus the District of Columbia. Results show that a composite measure is strongly correlated (R=0.89) with counts of alcohol outlets generated from official state records. Analyses based on Generalized Estimation Equation models show that community and contextual factors have little impact on the concordance between the two data sources. There are also minimal inter-state differences in the level of agreement. To validate the use of a convenient secondary data set (ZIP-BP) it is important to have a high correlation with the more complex, high quality and more costly data product (i.e., datasets based on the acquisition and geocoding of state and local records) and then to clearly demonstrate that the discrepancy between the two to be unrelated to relevant explanatory variables. Thus our overall findings support the adequacy of using a conveniently available data set (ZIP-BP data) to estimate alcohol outlet densities in ZIP code areas in future research. Copyright © 2011 Elsevier Ltd. All rights reserved.

46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

Code of Federal Regulations, 2011 CFR

2011-10-01

... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST... Inspections § 131.580 Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be serviced...

46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

Code of Federal Regulations, 2010 CFR

2010-10-01

... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST... Inspections § 131.580 Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be serviced...

Universality of the Volume Bound in Slow-Roll Eternal Inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubovsky, Sergei; Senatore, Leonardo; Villadoro, Giovanni

2012-03-28

It has recently been shown that in single field slow-roll inflation the total volume cannot grow by a factor larger than e{sup S{sub dS}/2} without becoming infinite. The bound is saturated exactly at the phase transition to eternal inflation where the probability to produce infinite volume becomes non zero. We show that the bound holds sharply also in any space-time dimensions, when arbitrary higher-dimensional operators are included and in the multi-field inflationary case. The relation with the entropy of de Sitter and the universality of the bound strengthen the case for a deeper holographic interpretation. As a spin-off we providemore » the formalism to compute the probability distribution of the volume after inflation for generic multi-field models, which might help to address questions about the population of vacua of the landscape during slow-roll inflation.« less

Neighborhood walkability and active travel (walking and cycling) in New York City.

PubMed

Freeman, Lance; Neckerman, Kathryn; Schwartz-Soicher, Ofira; Quinn, James; Richards, Catherine; Bader, Michael D M; Lovasi, Gina; Jack, Darby; Weiss, Christopher; Konty, Kevin; Arno, Peter; Viola, Deborah; Kerker, Bonnie; Rundle, Andrew G

2013-08-01

Urban planners have suggested that built environment characteristics can support active travel (walking and cycling) and reduce sedentary behavior. This study assessed whether engagement in active travel is associated with neighborhood walkability measured for zip codes in New York City. Data were analyzed on engagement in active travel and the frequency of walking or biking ten blocks or more in the past month, from 8,064 respondents to the New York City 2003 Community Health Survey (CHS). A neighborhood walkability scale that measures: residential, intersection, and subway stop density; land use mix; and the ratio of retail building floor area to retail land area was calculated for each zip code. Data were analyzed using zero-inflated negative binomial regression incorporating survey sample weights and adjusting for respondents' sociodemographic characteristics. Overall, 44 % of respondents reported no episodes of active travel and among those who reported any episode, the mean number was 43.2 episodes per month. Comparing the 75th to the 25th percentile of zip code walkability, the odds ratio for reporting zero episodes of active travel was 0.71 (95 % CI 0.61, 0.83) and the exponentiated beta coefficient for the count of episodes of active travel was 1.13 (95 % CI 1.06, 1.21). Associations between lower walkability and reporting zero episodes of active travel were significantly stronger for non-Hispanic Whites as compared to non-Hispanic Blacks and to Hispanics and for those living in higher income zip codes. The results suggest that neighborhood walkability is associated with higher engagement in active travel.

Normal forms for Poisson maps and symplectic groupoids around Poisson transversals

NASA Astrophysics Data System (ADS)

Frejlich, Pedro; Mărcuț, Ioan

2018-03-01

Poisson transversals are submanifolds in a Poisson manifold which intersect all symplectic leaves transversally and symplectically. In this communication, we prove a normal form theorem for Poisson maps around Poisson transversals. A Poisson map pulls a Poisson transversal back to a Poisson transversal, and our first main result states that simultaneous normal forms exist around such transversals, for which the Poisson map becomes transversally linear, and intertwines the normal form data of the transversals. Our second result concerns symplectic integrations. We prove that a neighborhood of a Poisson transversal is integrable exactly when the Poisson transversal itself is integrable, and in that case we prove a normal form theorem for the symplectic groupoid around its restriction to the Poisson transversal, which puts all structure maps in normal form. We conclude by illustrating our results with examples arising from Lie algebras.

Normal forms for Poisson maps and symplectic groupoids around Poisson transversals.

PubMed

Frejlich, Pedro; Mărcuț, Ioan

2018-01-01

Poisson transversals are submanifolds in a Poisson manifold which intersect all symplectic leaves transversally and symplectically. In this communication, we prove a normal form theorem for Poisson maps around Poisson transversals. A Poisson map pulls a Poisson transversal back to a Poisson transversal, and our first main result states that simultaneous normal forms exist around such transversals, for which the Poisson map becomes transversally linear, and intertwines the normal form data of the transversals. Our second result concerns symplectic integrations. We prove that a neighborhood of a Poisson transversal is integrable exactly when the Poisson transversal itself is integrable, and in that case we prove a normal form theorem for the symplectic groupoid around its restriction to the Poisson transversal, which puts all structure maps in normal form. We conclude by illustrating our results with examples arising from Lie algebras.

Efficient Proximity Computation Techniques Using ZIP Code Data for Smart Cities †

PubMed Central

Murdani, Muhammad Harist; Hong, Bonghee

2018-01-01

In this paper, we are interested in computing ZIP code proximity from two perspectives, proximity between two ZIP codes (Ad-Hoc) and neighborhood proximity (Top-K). Such a computation can be used for ZIP code-based target marketing as one of the smart city applications. A naïve approach to this computation is the usage of the distance between ZIP codes. We redefine a distance metric combining the centroid distance with the intersecting road network between ZIP codes by using a weighted sum method. Furthermore, we prove that the results of our combined approach conform to the characteristics of distance measurement. We have proposed a general and heuristic approach for computing Ad-Hoc proximity, while for computing Top-K proximity, we have proposed a general approach only. Our experimental results indicate that our approaches are verifiable and effective in reducing the execution time and search space. PMID:29587366

Efficient Proximity Computation Techniques Using ZIP Code Data for Smart Cities †.

PubMed

Murdani, Muhammad Harist; Kwon, Joonho; Choi, Yoon-Ho; Hong, Bonghee

2018-03-24

In this paper, we are interested in computing ZIP code proximity from two perspectives, proximity between two ZIP codes ( Ad-Hoc ) and neighborhood proximity ( Top-K ). Such a computation can be used for ZIP code-based target marketing as one of the smart city applications. A naïve approach to this computation is the usage of the distance between ZIP codes. We redefine a distance metric combining the centroid distance with the intersecting road network between ZIP codes by using a weighted sum method. Furthermore, we prove that the results of our combined approach conform to the characteristics of distance measurement. We have proposed a general and heuristic approach for computing Ad-Hoc proximity, while for computing Top-K proximity, we have proposed a general approach only. Our experimental results indicate that our approaches are verifiable and effective in reducing the execution time and search space.

Multivariate random-parameters zero-inflated negative binomial regression model: an application to estimate crash frequencies at intersections.

PubMed

Dong, Chunjiao; Clarke, David B; Yan, Xuedong; Khattak, Asad; Huang, Baoshan

2014-09-01

Crash data are collected through police reports and integrated with road inventory data for further analysis. Integrated police reports and inventory data yield correlated multivariate data for roadway entities (e.g., segments or intersections). Analysis of such data reveals important relationships that can help focus on high-risk situations and coming up with safety countermeasures. To understand relationships between crash frequencies and associated variables, while taking full advantage of the available data, multivariate random-parameters models are appropriate since they can simultaneously consider the correlation among the specific crash types and account for unobserved heterogeneity. However, a key issue that arises with correlated multivariate data is the number of crash-free samples increases, as crash counts have many categories. In this paper, we describe a multivariate random-parameters zero-inflated negative binomial (MRZINB) regression model for jointly modeling crash counts. The full Bayesian method is employed to estimate the model parameters. Crash frequencies at urban signalized intersections in Tennessee are analyzed. The paper investigates the performance of MZINB and MRZINB regression models in establishing the relationship between crash frequencies, pavement conditions, traffic factors, and geometric design features of roadway intersections. Compared to the MZINB model, the MRZINB model identifies additional statistically significant factors and provides better goodness of fit in developing the relationships. The empirical results show that MRZINB model possesses most of the desirable statistical properties in terms of its ability to accommodate unobserved heterogeneity and excess zero counts in correlated data. Notably, in the random-parameters MZINB model, the estimated parameters vary significantly across intersections for different crash types. Copyright © 2014 Elsevier Ltd. All rights reserved.

Physiological Response to Reward and Extinction Predicts Alcohol, Marijuana, and Cigarette Use Two Years Later

PubMed Central

Derefinko, Karen J.; Eisenlohr-Moul, Tory A.; Peters, Jessica R.; Roberts, Walter; Walsh, Erin C.; Milich, Richard; Lynam, Donald R.

2017-01-01

Background Physiological responses to reward and extinction are believed to represent the Behavioral Activation System (BAS) and Behavioral Inhibition System (BIS) constructs of Reinforcement Sensitivity Theory and underlie externalizing behaviors, including substance use. However, little research has examined these relations directly. Methods We assessed individuals’ cardiac pre-ejection periods (PEP) and electrodermal responses (EDR) during reward and extinction trials through the “Number Elimination Game” paradigm. Responses represented BAS and BIS, respectively. We then examined whether these responses provided incremental utility in the prediction of future alcohol, marijuana, and cigarette use. Results Zero-inflated Poisson (ZIP) regression models were used to examine the predictive utility of physiological BAS and BIS responses above and beyond previous substance use. Physiological responses accounted for incremental variance over previous use. Low BAS responses during reward predicted frequency of alcohol use at year 3. Low BAS responses during reward and extinction and high BIS responses during extinction predicted frequency of marijuana use at year 3. For cigarette use, low BAS response during extinction predicted use at year 3. Conclusions These findings suggest that the constructs of Reinforcement Sensitivity Theory, as assessed through physiology, contribute to the longitudinal maintenance of substance use. PMID:27306728

46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

Code of Federal Regulations, 2012 CFR

2012-10-01

... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST..., and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be serviced... maintenance of inflatable rescue boats must follow the manufacturers' instructions. Each repair, except an...

46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

Code of Federal Regulations, 2013 CFR

2013-10-01

... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST..., and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be serviced... maintenance of inflatable rescue boats must follow the manufacturers' instructions. Each repair, except an...

46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

Code of Federal Regulations, 2014 CFR

2014-10-01

... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST..., and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be serviced... maintenance of inflatable rescue boats must follow the manufacturers' instructions. Each repair, except an...

Hepatic ZIP14-mediated zinc transport is required for adaptation to endoplasmic reticulum stress.

PubMed

Kim, Min-Hyun; Aydemir, Tolunay B; Kim, Jinhee; Cousins, Robert J

2017-07-18

Extensive endoplasmic reticulum (ER) stress damages the liver, causing apoptosis and steatosis despite the activation of the unfolded protein response (UPR). Restriction of zinc from cells can induce ER stress, indicating that zinc is essential to maintain normal ER function. However, a role for zinc during hepatic ER stress is largely unknown despite important roles in metabolic disorders, including obesity and nonalcoholic liver disease. We have explored a role for the metal transporter ZIP14 during pharmacologically and high-fat diet-induced ER stress using Zip14 -/- (KO) mice, which exhibit impaired hepatic zinc uptake. Here, we report that ZIP14-mediated hepatic zinc uptake is critical for adaptation to ER stress, preventing sustained apoptosis and steatosis. Impaired hepatic zinc uptake in Zip14 KO mice during ER stress coincides with greater expression of proapoptotic proteins. ER stress-induced Zip14 KO mice show greater levels of hepatic steatosis due to higher expression of genes involved in de novo fatty acid synthesis, which are suppressed in ER stress-induced WT mice. During ER stress, the UPR-activated transcription factors ATF4 and ATF6α transcriptionally up-regulate Zip14 expression. We propose ZIP14 mediates zinc transport into hepatocytes to inhibit protein-tyrosine phosphatase 1B (PTP1B) activity, which acts to suppress apoptosis and steatosis associated with hepatic ER stress. Zip14 KO mice showed greater hepatic PTP1B activity during ER stress. These results show the importance of zinc trafficking and functional ZIP14 transporter activity for adaptation to ER stress associated with chronic metabolic disorders.

The Role of Depressive Symptoms, Family Invalidation and Behavioral Impulsivity in the Occurrence and Repetition of Non-Suicidal Self-Injury in Chinese Adolescents: A 2-Year Follow-Up Study

ERIC Educational Resources Information Center

You, Jianing; Leung, Freedom

2012-01-01

This study used zero-inflated poisson regression analysis to examine the role of depressive symptoms, family invalidation, and behavioral impulsivity in the occurrence and repetition of non-suicidal self-injury among Chinese community adolescents over a 2-year period. Participants, 4782 high school students, were assessed twice during the…

Mm-size bistable zipping dielectric elastomer actuators for integrated microfluidics

NASA Astrophysics Data System (ADS)

Maffli, Luc; Rosset, Samuel; Shea, Herbert R.

2013-04-01

We report on a new structure of Dielectric Elastomer Actuators (DEAs) called zipping DEAs, which have a set of unique characteristics that are a good match for the requirements of electrically-powered integrated microfluidic pumping and/or valving units as well as Braille displays. The zipping DEAs operate by pulling electrostatically an elastomer membrane in contact with the rigid sidewalls of a sloped chamber. In this work, we report on fully functional mm-size zipping DEAs that demonstrate a complete sealing of the chamber sidewalls and a tunable bistable behavior, and compare the measurements with an analytical model. Compared to our first generation of devices, we are able vary the sidewall angle and benefit therefore from more flexibility to study the requirements to make fully functional actuators. In particular, we show that with Nusil CF19 as membrane material (1.2 MPa Young's modulus), it is possible to zip completely 2.3 mm diameter chambers with 15° and 21° sidewalls angle equibiaxially prestretched to λ0=1.12 and 15° chambers with λ0=1.27.

46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2013 CFR

2013-10-01

... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD..., inflatable life jackets, and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant... other standard specified by the Commandant. (e) Repair and maintenance of inflated rescue boats must be...

46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2012 CFR

2012-10-01

... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD..., inflatable life jackets, and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant... other standard specified by the Commandant. (e) Repair and maintenance of inflated rescue boats must be...

46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2014 CFR

2014-10-01

... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD..., inflatable life jackets, and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant... other standard specified by the Commandant. (e) Repair and maintenance of inflated rescue boats must be...

Genome-wide analysis of the homeodomain-leucine zipper (HD-ZIP) gene family in peach (Prunus persica).

PubMed

Zhang, C H; Ma, R J; Shen, Z J; Sun, X; Korir, N K; Yu, M L

2014-04-08

In this study, 33 homeodomain-leucine zipper (HD-ZIP) genes were identified in peach using the HD-ZIP amino acid sequences of Arabidopsis thaliana as a probe. Based on the phylogenetic analysis and the individual gene or protein characteristics, the HD-ZIP gene family in peach can be classified into 4 subfamilies, HD-ZIP I, II, III, and IV, containing 14, 7, 4, and 8 members, respectively. The most closely related peach HD-ZIP members within the same subfamilies shared very similar gene structure in terms of either intron/exon numbers or lengths. Almost all members of the same subfamily shared common motif compositions, thereby implying that the HD-ZIP proteins within the same subfamily may have functional similarity. The 33 peach HD-ZIP genes were distributed across scaffolds 1 to 7. Although the primary structure varied among HD-ZIP family proteins, their tertiary structures were similar. The results from this study will be useful in selecting candidate genes from specific subfamilies for functional analysis.

Genome-Wide Identification and Structural Analysis of bZIP Transcription Factor Genes in Brassica napus.

PubMed

Zhou, Yan; Xu, Daixiang; Jia, Ledong; Huang, Xiaohu; Ma, Guoqiang; Wang, Shuxian; Zhu, Meichen; Zhang, Aoxiang; Guan, Mingwei; Lu, Kun; Xu, Xinfu; Wang, Rui; Li, Jiana; Qu, Cunmin

2017-10-24

The basic region/leucine zipper motif (bZIP) transcription factor family is one of the largest families of transcriptional regulators in plants. bZIP genes have been systematically characterized in some plants, but not in rapeseed ( Brassica napus ). In this study, we identified 247 BnbZIP genes in the rapeseed genome, which we classified into 10 subfamilies based on phylogenetic analysis of their deduced protein sequences. The BnbZIP genes were grouped into functional clades with Arabidopsis genes with similar putative functions, indicating functional conservation. Genome mapping analysis revealed that the BnbZIPs are distributed unevenly across all 19 chromosomes, and that some of these genes arose through whole-genome duplication and dispersed duplication events. All expression profiles of 247 bZIP genes were extracted from RNA-sequencing data obtained from 17 different B . napus ZS11 tissues with 42 various developmental stages. These genes exhibited different expression patterns in various tissues, revealing that these genes are differentially regulated. Our results provide a valuable foundation for functional dissection of the different BnbZIP homologs in B . napus and its parental lines and for molecular breeding studies of bZIP genes in B . napus .

Genome-Wide Identification and Structural Analysis of bZIP Transcription Factor Genes in Brassica napus

PubMed Central

Zhou, Yan; Xu, Daixiang; Jia, Ledong; Huang, Xiaohu; Ma, Guoqiang; Wang, Shuxian; Zhu, Meichen; Zhang, Aoxiang; Guan, Mingwei; Xu, Xinfu; Wang, Rui; Li, Jiana

2017-01-01

The basic region/leucine zipper motif (bZIP) transcription factor family is one of the largest families of transcriptional regulators in plants. bZIP genes have been systematically characterized in some plants, but not in rapeseed (Brassica napus). In this study, we identified 247 BnbZIP genes in the rapeseed genome, which we classified into 10 subfamilies based on phylogenetic analysis of their deduced protein sequences. The BnbZIP genes were grouped into functional clades with Arabidopsis genes with similar putative functions, indicating functional conservation. Genome mapping analysis revealed that the BnbZIPs are distributed unevenly across all 19 chromosomes, and that some of these genes arose through whole-genome duplication and dispersed duplication events. All expression profiles of 247 bZIP genes were extracted from RNA-sequencing data obtained from 17 different B. napus ZS11 tissues with 42 various developmental stages. These genes exhibited different expression patterns in various tissues, revealing that these genes are differentially regulated. Our results provide a valuable foundation for functional dissection of the different BnbZIP homologs in B. napus and its parental lines and for molecular breeding studies of bZIP genes in B. napus. PMID:29064393

Hepatic ZIP14-mediated zinc transport is required for adaptation to endoplasmic reticulum stress

PubMed Central

Kim, Min-Hyun; Aydemir, Tolunay B.; Kim, Jinhee; Cousins, Robert J.

2017-01-01

Extensive endoplasmic reticulum (ER) stress damages the liver, causing apoptosis and steatosis despite the activation of the unfolded protein response (UPR). Restriction of zinc from cells can induce ER stress, indicating that zinc is essential to maintain normal ER function. However, a role for zinc during hepatic ER stress is largely unknown despite important roles in metabolic disorders, including obesity and nonalcoholic liver disease. We have explored a role for the metal transporter ZIP14 during pharmacologically and high-fat diet–induced ER stress using Zip14−/− (KO) mice, which exhibit impaired hepatic zinc uptake. Here, we report that ZIP14-mediated hepatic zinc uptake is critical for adaptation to ER stress, preventing sustained apoptosis and steatosis. Impaired hepatic zinc uptake in Zip14 KO mice during ER stress coincides with greater expression of proapoptotic proteins. ER stress-induced Zip14 KO mice show greater levels of hepatic steatosis due to higher expression of genes involved in de novo fatty acid synthesis, which are suppressed in ER stress-induced WT mice. During ER stress, the UPR-activated transcription factors ATF4 and ATF6α transcriptionally up-regulate Zip14 expression. We propose ZIP14 mediates zinc transport into hepatocytes to inhibit protein-tyrosine phosphatase 1B (PTP1B) activity, which acts to suppress apoptosis and steatosis associated with hepatic ER stress. Zip14 KO mice showed greater hepatic PTP1B activity during ER stress. These results show the importance of zinc trafficking and functional ZIP14 transporter activity for adaptation to ER stress associated with chronic metabolic disorders. PMID:28673968

Inflatable Re-Entry Vehicle Experiment (IRVE) Design Overview

NASA Technical Reports Server (NTRS)

Hughes, Stephen J.; Dillman, Robert A.; Starr, Brett R.; Stephan, Ryan A.; Lindell, Michael C.; Player, Charles J.; Cheatwood, F. McNeil

2005-01-01

integrity when exposed to a relevant dynamic pressure and aerodynamic stability of the inflatable system. Structural integrity and structural response of the inflatable will be verified with photogrammetric measurements of the back side of the aeroshell in flight. Aerodynamic stability as well as drag performance will be verified with on board inertial measurements and radar tracking from multiple ground radar stations. The experiment will yield valuable information about zero-g vacuum deployment dynamics of the flexible inflatable structure with both inertial and photographic measurements. In addition to demonstrating inflatable technology, IRVE will validate structural, aerothermal, and trajectory modeling techniques for the inflatable. Structural response determined from photogrammetrics will validate structural models, skin temperature measurements and additional in-depth temperature measurements will validate material thermal performance models, and on board inertial measurements along with radar tracking from multiple ground radar stations will validate trajectory simulation models.

hZIP1 zinc uptake transporter down regulation and zinc depletion in prostate cancer

PubMed Central

Franklin, Renty B; Feng, Pei; Milon, B; Desouki, Mohamed M; Singh, Keshav K; Kajdacsy-Balla, André; Bagasra, Omar; Costello, Leslie C

2005-01-01

Background The genetic and molecular mechanisms responsible for and associated with the development and progression of prostate malignancy are largely unidentified. The peripheral zone is the major region of the human prostate gland where malignancy develops. The normal peripheral zone glandular epithelium has the unique function of accumulating high levels of zinc. In contrast, the ability to accumulate zinc is lost in the malignant cells. The lost ability of the neoplastic epithelial cells to accumulate zinc is a consistent factor in their development of malignancy. Recent studies identified ZIP1 (SLC39A1) as an important zinc transporter involved in zinc accumulation in prostate cells. Therefore, we investigated the possibility that down-regulation of hZIP1 gene expression might be involved in the inability of malignant prostate cells to accumulate zinc. To address this issue, the expression of hZIP1 and the depletion of zinc in malignant versus non-malignant prostate glands of prostate cancer tissue sections were analyzed. hZIP1 expression was also determined in malignant prostate cell lines. Results hZIP1 gene expression, ZIP1 transporter protein, and cellular zinc were prominent in normal peripheral zone glandular epithelium and in benign hyperplastic glands (also zinc accumulating glands). In contrast, hZIP1 gene expression and transporter protein were markedly down-regulated and zinc was depleted in adenocarcinomatous glands and in prostate intra-epithelial neoplastic foci (PIN). These changes occur early in malignancy and are sustained during its progression in the peripheral zone. hZIP1 is also expressed in the malignant cell lines LNCaP, PC-3, DU-145; and in the nonmalignant cell lines HPr-1 and BPH-1. Conclusion The studies clearly establish that hZIP1 gene expression is down regulated and zinc is depleted in adenocarcinomatous glands. The fact that all the malignant cell lines express hZIP1 indicates that the down-regulation in adenocarcinomatous

46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2014 CFR

2014-10-01

... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... liferafts, inflatable buoyant apparatus, inflatable life jackets, and inflated rescue boats. (a) An... inflated rescue boats must be in accordance with the manufacturer's instructions. All repairs must be made...

46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2013 CFR

2013-10-01

... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... liferafts, inflatable buoyant apparatus, inflatable life jackets, and inflated rescue boats. (a) An... inflated rescue boats must be in accordance with the manufacturer's instructions. All repairs must be made...

46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2012 CFR

2012-10-01

... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... liferafts, inflatable buoyant apparatus, inflatable life jackets, and inflated rescue boats. (a) An... inflated rescue boats must be in accordance with the manufacturer's instructions. All repairs must be made...

DISCRETE COMPOUND POISSON PROCESSES AND TABLES OF THE GEOMETRIC POISSON DISTRIBUTION.

DTIC Science & Technology

A concise summary of the salient properties of discrete Poisson processes , with emphasis on comparing the geometric and logarithmic Poisson processes . The...the geometric Poisson process are given for 176 sets of parameter values. New discrete compound Poisson processes are also introduced. These...processes have properties that are particularly relevant when the summation of several different Poisson processes is to be analyzed. This study provides the

Knockdown of Zinc Transporter ZIP5 by RNA Interference Inhibits Esophageal Cancer Growth In Vivo.

PubMed

Li, Qian; Jin, Jing; Liu, Jianghui; Wang, Liqun; He, Yutong

2016-01-01

We recently found that SLC39A5 (ZIP5), a zinc transporter, is overexpressed in esophageal cancer. Downregulation of ZIP5 inhibited the proliferation, migration, and invasion of the esophageal cancer cell line KYSE170 in vitro. In this study, we found that downregulation of SLC39A5 (ZIP5) by interference resulted in a significant reduction in esophageal cancer tumor volume and weight in vivo. COX2 (cyclooxygenase 2) expression was decreased and E-cadherin expression was increased in the KYSE170K xenografts, which was caused by the downregulation of ZIP5. However, we did not find that the downregulation of ZIP5 caused a change in the relative expressions of cyclin D1, VEGF (vascular endothelial growth factor), MMP9 (matrix metalloprotein 9), and Bcl-2 (B-cell lymphoma/leukmia-2) mRNA or an alteration in the average level of zinc in the peripheral blood and xenografts in vivo. Collectively, these findings indicate that knocking down ZIP5 by small interfering RNA (siRNA) might be a novel treatment strategy for esophageal cancer with ZIP5 overexpression.

Knockdown of zinc transporter ZIP8 expression inhibits neuroblastoma progression and metastasis in vitro.

PubMed

Mei, Zhengrong; Yan, Pengke; Wang, Ying; Liu, Shaozhi; He, Fang

2018-05-02

Neuroblastoma is one of the leading causes of cancer‑associated mortality worldwide, particularly in children, partially due to the absence of effective therapeutic targets and diagnostic biomarkers. Therefore, novel molecular targets are critical to the development of therapeutic approaches for neuroblastoma. In the present study, the functions of zinc transporter ZIP8 (Zip8), a member of the zinc transporting protein family, were investigated as novel molecular targets in neuroblastoma cancer cells. The proliferation rates of neuroblastoma cancer cells were significantly decreased when Zip8 was knocked down by lentiviral‑mediated RNA interference. Study of the molecular mechanism suggested that Zip8 modulated the expression of key genes involved in the nuclear factor‑κB signaling pathway. Furthermore, Zip8 depletion suppressed the migratory potential of neuroblastoma cancer cells by reducing the expression levels of matrix metalloproteinases. In conclusion, the results of the present study suggested that Zip8 was an important regulator of neuroblastoma cell proliferation and migration, indicating that Zip8 may be a potential anticancer therapeutic target and a promising diagnostic biomarker for human neuroblastoma.

Arabidopsis HD-Zip II transcription factors control apical embryo development and meristem function.

PubMed

Turchi, Luana; Carabelli, Monica; Ruzza, Valentino; Possenti, Marco; Sassi, Massimiliano; Peñalosa, Andrés; Sessa, Giovanna; Salvi, Sergio; Forte, Valentina; Morelli, Giorgio; Ruberti, Ida

2013-05-01

The Arabidopsis genome encodes ten Homeodomain-Leucine zipper (HD-Zip) II proteins. ARABIDOPSIS THALIANA HOMEOBOX 2 (ATHB2), HOMEOBOX ARABIDOPSIS THALIANA 1 (HAT1), HAT2, HAT3 and ATHB4 are regulated by changes in the red/far red light ratio that induce shade avoidance in most of the angiosperms. Here, we show that progressive loss of HAT3, ATHB4 and ATHB2 activity causes developmental defects from embryogenesis onwards in white light. Cotyledon development and number are altered in hat3 athb4 embryos, and these defects correlate with changes in auxin distribution and response. athb2 gain-of-function mutation and ATHB2 expression driven by its promoter in hat3 athb4 result in significant attenuation of phenotypes, thus demonstrating that ATHB2 is functionally redundant to HAT3 and ATHB4. In analogy to loss-of-function mutations in HD-Zip III genes, loss of HAT3 and ATHB4 results in organ polarity defects, whereas triple hat3 athb4 athb2 mutants develop one or two radialized cotyledons and lack an active shoot apical meristem (SAM). Consistent with overlapping expression pattern of HD-Zip II and HD-Zip III gene family members, bilateral symmetry and SAM defects are enhanced when hat3 athb4 is combined with mutations in PHABULOSA (PHB), PHAVOLUTA (PHV) or REVOLUTA (REV). Finally, we show that ATHB2 is part of a complex regulatory circuit directly involving both HD-Zip II and HD-Zip III proteins. Taken together, our study provides evidence that a genetic system consisting of HD-Zip II and HD-Zip III genes cooperates in establishing bilateral symmetry and patterning along the adaxial-abaxial axis in the embryo as well as in controlling SAM activity.

Poisson Coordinates.

PubMed

Li, Xian-Ying; Hu, Shi-Min

2013-02-01

Harmonic functions are the critical points of a Dirichlet energy functional, the linear projections of conformal maps. They play an important role in computer graphics, particularly for gradient-domain image processing and shape-preserving geometric computation. We propose Poisson coordinates, a novel transfinite interpolation scheme based on the Poisson integral formula, as a rapid way to estimate a harmonic function on a certain domain with desired boundary values. Poisson coordinates are an extension of the Mean Value coordinates (MVCs) which inherit their linear precision, smoothness, and kernel positivity. We give explicit formulas for Poisson coordinates in both continuous and 2D discrete forms. Superior to MVCs, Poisson coordinates are proved to be pseudoharmonic (i.e., they reproduce harmonic functions on n-dimensional balls). Our experimental results show that Poisson coordinates have lower Dirichlet energies than MVCs on a number of typical 2D domains (particularly convex domains). As well as presenting a formula, our approach provides useful insights for further studies on coordinates-based interpolation and fast estimation of harmonic functions.

Bayesian analysis of zero inflated spatiotemporal HIV/TB child mortality data through the INLA and SPDE approaches: Applied to data observed between 1992 and 2010 in rural North East South Africa

NASA Astrophysics Data System (ADS)

Musenge, Eustasius; Chirwa, Tobias Freeman; Kahn, Kathleen; Vounatsou, Penelope

2013-06-01

Longitudinal mortality data with few deaths usually have problems of zero-inflation. This paper presents and applies two Bayesian models which cater for zero-inflation, spatial and temporal random effects. To reduce the computational burden experienced when a large number of geo-locations are treated as a Gaussian field (GF) we transformed the field to a Gaussian Markov Random Fields (GMRF) by triangulation. We then modelled the spatial random effects using the Stochastic Partial Differential Equations (SPDEs). Inference was done using a computationally efficient alternative to Markov chain Monte Carlo (MCMC) called Integrated Nested Laplace Approximation (INLA) suited for GMRF. The models were applied to data from 71,057 children aged 0 to under 10 years from rural north-east South Africa living in 15,703 households over the years 1992-2010. We found protective effects on HIV/TB mortality due to greater birth weight, older age and more antenatal clinic visits during pregnancy (adjusted RR (95% CI)): 0.73(0.53;0.99), 0.18(0.14;0.22) and 0.96(0.94;0.97) respectively. Therefore childhood HIV/TB mortality could be reduced if mothers are better catered for during pregnancy as this can reduce mother-to-child transmissions and contribute to improved birth weights. The INLA and SPDE approaches are computationally good alternatives in modelling large multilevel spatiotemporal GMRF data structures.

Basic leucine zipper transcription factor SlbZIP1 mediates salt and drought stress tolerance in tomato.

PubMed

Zhu, Mingku; Meng, Xiaoqing; Cai, Jing; Li, Ge; Dong, Tingting; Li, Zongyun

2018-05-08

Basic region/leucine zipper (bZIP) transcription factors perform as crucial regulators in ABA-mediated stress response in plants. Nevertheless, the functions for most bZIP family members in tomato remain to be deciphered. Here we examined the functional characterization of SlbZIP1 under salt and drought stresses in tomato. Silencing of SlbZIP1 in tomato resulted in reduced expression of multiple ABA biosynthesis- and signal transduction-related genes in transgenic plants. In stress assays, SlbZIP1-RNAi transgenic plants exhibited reduced tolerance to salt and drought stresses compared with WT plants, as are evaluated by multiple physiological parameters associated with stress responses, such as decreased ABA, chlorophyll contents and CAT activity, and increased MDA content. In addition, RNA-seq analysis of transgenic plants revealed that the transcription levels of multiple genes encoding defense proteins related to responses to abiotic stress (e.g. endochitinase, peroxidases, and lipid transfer proteins) and biotic stress (e.g. pathogenesis-related proteins) were downregulated in SlbZIP1-RNAi plants, suggesting that SlbZIP1 plays a role in regulating the genes related to biotic and abiotic stress response. Collectively, the data suggest that SlbZIP1 exerts an essential role in salt and drought stress tolerance through modulating an ABA-mediated pathway, and SlbZIP1 may hold potential applications in the engineering of salt- and drought-tolerant tomato cultivars.

A role for the Drosophila zinc transporter Zip88E in protecting against dietary zinc toxicity.

PubMed

Richards, Christopher D; Warr, Coral G; Burke, Richard

2017-01-01

Zinc absorption in animals is thought to be regulated in a local, cell autonomous manner with intestinal cells responding to dietary zinc content. The Drosophila zinc transporter Zip88E shows strong sequence similarity to Zips 42C.1, 42C.2 and 89B as well as mammalian Zips 1, 2 and 3, suggesting that it may act in concert with the apically-localised Drosophila zinc uptake transporters to facilitate dietary zinc absorption by importing ions into the midgut enterocytes. However, the functional characterisation of Zip88E presented here indicates that Zip88E may instead play a role in detecting and responding to zinc toxicity. Larvae homozygous for a null Zip88E allele are viable yet display heightened sensitivity to elevated levels of dietary zinc. This decreased zinc tolerance is accompanied by an overall decrease in Metallothionein B transcription throughout the larval midgut. A Zip88E reporter gene is expressed only in the salivary glands, a handful of enteroendocrine cells at the boundary between the anterior and middle midgut regions, and in two parallel strips of sensory cell projections connecting to the larval ventral ganglion. Zip88E expression solely in this restricted subset of cells is sufficient to rescue the Zip88E mutant phenotype. Together, our data suggest that Zip88E may be functioning in a small subset of cells to detect excessive zinc levels and induce a systemic response to reduce dietary zinc absorption and hence protect against toxicity.

Genome-wide characterization and analysis of bZIP transcription factor gene family related to abiotic stress in cassava.

PubMed

Hu, Wei; Yang, Hubiao; Yan, Yan; Wei, Yunxie; Tie, Weiwei; Ding, Zehong; Zuo, Jiao; Peng, Ming; Li, Kaimian

2016-03-07

The basic leucine zipper (bZIP) transcription factor family plays crucial roles in various aspects of biological processes. Currently, no information is available regarding the bZIP family in the important tropical crop cassava. Herein, 77 bZIP genes were identified from cassava. Evolutionary analysis indicated that MebZIPs could be divided into 10 subfamilies, which was further supported by conserved motif and gene structure analyses. Global expression analysis suggested that MebZIPs showed similar or distinct expression patterns in different tissues between cultivated variety and wild subspecies. Transcriptome analysis of three cassava genotypes revealed that many MebZIP genes were activated by drought in the root of W14 subspecies, indicating the involvement of these genes in the strong resistance of cassava to drought. Expression analysis of selected MebZIP genes in response to osmotic, salt, cold, ABA, and H2O2 suggested that they might participate in distinct signaling pathways. Our systematic analysis of MebZIPs reveals constitutive, tissue-specific and abiotic stress-responsive candidate MebZIP genes for further functional characterization in planta, yields new insights into transcriptional regulation of MebZIP genes, and lays a foundation for understanding of bZIP-mediated abiotic stress response.

Variable- and Person-Centered Approaches to the Analysis of Early Adolescent Substance Use: Linking Peer, Family, and Intervention Effects with Developmental Trajectories

ERIC Educational Resources Information Center

Connell, Arin M.; Dishion, Thomas J.; Deater-Deckard, Kirby

2006-01-01

This 4-year study of 698 young adolescents examined the covariates of early onset substance use from Grade 6 through Grade 9. The youth were randomly assigned to a family-centered Adolescent Transitions Program (ATP) condition. Variable-centered (zero-inflated Poisson growth model) and person-centered (latent growth mixture model) approaches were…

46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2011 CFR

2011-10-01

... inflatable liferaft or inflatable buoyant apparatus must be serviced at a facility specifically approved by... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... Operational Readiness, Maintenance, and Inspection of Lifesaving Equipment § 185.730 Servicing of inflatable...

46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2010 CFR

2010-10-01

... inflatable liferaft or inflatable buoyant apparatus must be serviced at a facility specifically approved by... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... Operational Readiness, Maintenance, and Inspection of Lifesaving Equipment § 185.730 Servicing of inflatable...

Salt and drought stress and ABA responses related to bZIP genes from V. radiata and V. angularis.

PubMed

Wang, Lanfen; Zhu, Jifeng; Li, Xiaoming; Wang, Shumin; Wu, Jing

2018-04-20

Mung bean and adzuki bean are warm-season legumes widely cultivated in China. However, bean production in major producing regions is limited by biotic and abiotic stress, such as drought and salt stress. Basic leucine zipper (bZIP) genes play key roles in responses to various biotic and abiotic stresses. However, only several bZIP genes involved in drought and salt stress in legumes, especially Vigna radiata and Vigna angularis, have been identified. In this study, we identified 54 and 50 bZIP proteins from whole-genome sequences of V. radiata and V. angularis, respectively. First, we comprehensively surveyed the characteristics of all bZIP genes, including their gene structure, chromosome distribution and motif composition. Phylogenetic trees showed that VrbZIP and VabZIP proteins were divided into ten clades comprising nine known and one unknown subgroup. The results of the nucleotide substitution rate of the orthologous gene pairs showed that bZIP proteins have undergone strong purifying selection: V. radiata and V. angularis diverged 1.25 million years ago (mya) to 9.20 mya (average of 4.95 mya). We also found that many cis-acting regulatory elements (CAREs) involved in abiotic stress and plant hormone responses were detected in the putative promoter regions of the bZIP genes. Finally, using the quantitative real-time PCR (qRT-PCR) method, we performed expression profiling of the bZIP genes in response to drought, salt and abscisic acid (ABA). We identified several bZIP genes that may be involved in drought and salt responses. Generally, our results provided useful and rich resources of VrbZIP and VabZIP genes for the functional characterization and understanding of bZIP transcription factors (TFs) in warm-season legumes. In addition, our results revealed important and interesting data - a subset of VrbZIP and VabZIP gene expression profiles in response to drought, salt and ABA stress. These results provide gene expression evidence for the selection of

A specific role for the ZipA protein in cell division: stabilization of the FtsZ protein.

PubMed

Pazos, Manuel; Natale, Paolo; Vicente, Miguel

2013-02-01

In Escherichia coli, the cell division protein FtsZ is anchored to the cytoplasmic membrane by the action of the bitopic membrane protein ZipA and the cytoplasmic protein FtsA. Although the presence of both ZipA and FtsA is strictly indispensable for cell division, an FtsA gain-of-function mutant FtsA* (R286W) can bypass the ZipA requirement for cell division. This observation casts doubts on the role of ZipA and its need for cell division. Maxicells are nucleoid-free bacterial cells used as a whole cell in vitro system to probe protein-protein interactions without the need of protein purification. We show that ZipA protects FtsZ from the ClpXP-directed degradation observed in E. coli maxicells and that ZipA-stabilized FtsZ forms membrane-attached spiral-like structures in the bacterial cytoplasm. The overproduction of the FtsZ-binding ZipA domain is sufficient to protect FtsZ from degradation, whereas other C-terminal ZipA partial deletions lacking it are not. Individual overproduction of the proto-ring component FtsA or its gain-of-function mutant FtsA* does not result in FtsZ protection. Overproduction of FtsA or FtsA* together with ZipA does not interfere with the FtsZ protection. Moreover, neither FtsA nor FtsA* protects FtsZ when overproduced together with ZipA mutants lacking the FZB domain. We propose that ZipA protects FtsZ from degradation by ClpP by making the FtsZ site of interaction unavailable to the ClpX moiety of the ClpXP protease. This role cannot be replaced by either FtsA or FtsA*, suggesting a unique function for ZipA in proto-ring stability.

Poplar PtabZIP1-like enhances lateral root formation and biomass growth under drought stress

DOE PAGES

Dash, Madhumita; Yordanov, Yordan S.; Georgieva, Tatyana; ...

2017-02-10

Developing drought-resistance varieties is a major goal for bioenergy crops, such as poplar (Populus), which will be grown on marginal lands with little or no water input. Root architecture can affect drought resistance, but few genes that affect root architecture in relation to water availability have been identified. Here in this study, using activation tagging in the prime bioenergy crop poplar, we have identified a mutant that overcomes the block of lateral root (LR) formation under osmotic stress. Positioning of the tag, validation of the activation and recapitulation showed that the phenotype is caused by the poplar PtabZIP1-like (PtabZIP1L) genemore » with highest homology to bZIP1 from Arabidopsis. PtabZIP1L is predominantly expressed in roots, particularly in zones where lateral root primordia (LRP) initiate and LR differentiate and emerge. Transgenics overexpressing PtabZIP1L showed precocious LRP and LR development, while PtabZIP1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of PtabZIP1L also resulted in modulation of key metabolites like proline, asparagine, valine and several flavonoids. Consistently, expression of both of the poplar Proline Dehydrogenase orthologs and two of the Flavonol Synthases genes was also increased and decreased in overexpressed and suppressed transgenics, respectively. These findings suggest that PtabZIP1L mediates LR development and drought resistance through modulation of multiple metabolic pathways.« less

Poplar PtabZIP1-like enhances lateral root formation and biomass growth under drought stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dash, Madhumita; Yordanov, Yordan S.; Georgieva, Tatyana

Developing drought-resistance varieties is a major goal for bioenergy crops, such as poplar (Populus), which will be grown on marginal lands with little or no water input. Root architecture can affect drought resistance, but few genes that affect root architecture in relation to water availability have been identified. Here in this study, using activation tagging in the prime bioenergy crop poplar, we have identified a mutant that overcomes the block of lateral root (LR) formation under osmotic stress. Positioning of the tag, validation of the activation and recapitulation showed that the phenotype is caused by the poplar PtabZIP1-like (PtabZIP1L) genemore » with highest homology to bZIP1 from Arabidopsis. PtabZIP1L is predominantly expressed in roots, particularly in zones where lateral root primordia (LRP) initiate and LR differentiate and emerge. Transgenics overexpressing PtabZIP1L showed precocious LRP and LR development, while PtabZIP1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of PtabZIP1L also resulted in modulation of key metabolites like proline, asparagine, valine and several flavonoids. Consistently, expression of both of the poplar Proline Dehydrogenase orthologs and two of the Flavonol Synthases genes was also increased and decreased in overexpressed and suppressed transgenics, respectively. These findings suggest that PtabZIP1L mediates LR development and drought resistance through modulation of multiple metabolic pathways.« less

Inverse Jacobi multiplier as a link between conservative systems and Poisson structures

NASA Astrophysics Data System (ADS)

García, Isaac A.; Hernández-Bermejo, Benito

2017-08-01

Some aspects of the relationship between conservativeness of a dynamical system (namely the preservation of a finite measure) and the existence of a Poisson structure for that system are analyzed. From the local point of view, due to the flow-box theorem we restrict ourselves to neighborhoods of singularities. In this sense, we characterize Poisson structures around the typical zero-Hopf singularity in dimension 3 under the assumption of having a local analytic first integral with non-vanishing first jet by connecting with the classical Poincaré center problem. From the global point of view, we connect the property of being strictly conservative (the invariant measure must be positive) with the existence of a Poisson structure depending on the phase space dimension. Finally, weak conservativeness in dimension two is introduced by the extension of inverse Jacobi multipliers as weak solutions of its defining partial differential equation and some of its applications are developed. Examples including Lotka-Volterra systems, quadratic isochronous centers, and non-smooth oscillators are provided.

A quantile count model of water depth constraints on Cape Sable seaside sparrows

USGS Publications Warehouse

Cade, B.S.; Dong, Q.

2008-01-01

1. A quantile regression model for counts of breeding Cape Sable seaside sparrows Ammodramus maritimus mirabilis (L.) as a function of water depth and previous year abundance was developed based on extensive surveys, 1992-2005, in the Florida Everglades. The quantile count model extends linear quantile regression methods to discrete response variables, providing a flexible alternative to discrete parametric distributional models, e.g. Poisson, negative binomial and their zero-inflated counterparts. 2. Estimates from our multiplicative model demonstrated that negative effects of increasing water depth in breeding habitat on sparrow numbers were dependent on recent occupation history. Upper 10th percentiles of counts (one to three sparrows) decreased with increasing water depth from 0 to 30 cm when sites were not occupied in previous years. However, upper 40th percentiles of counts (one to six sparrows) decreased with increasing water depth for sites occupied in previous years. 3. Greatest decreases (-50% to -83%) in upper quantiles of sparrow counts occurred as water depths increased from 0 to 15 cm when previous year counts were 1, but a small proportion of sites (5-10%) held at least one sparrow even as water depths increased to 20 or 30 cm. 4. A zero-inflated Poisson regression model provided estimates of conditional means that also decreased with increasing water depth but rates of change were lower and decreased with increasing previous year counts compared to the quantile count model. Quantiles computed for the zero-inflated Poisson model enhanced interpretation of this model but had greater lack-of-fit for water depths > 0 cm and previous year counts 1, conditions where the negative effect of water depths were readily apparent and fitted better with the quantile count model.

Molecular evolution of the HD-ZIP I gene family in legume genomes.

PubMed

Li, Zhen; Jiang, Haiyang; Zhou, Lingyan; Deng, Lin; Lin, Yongxiang; Peng, Xiaojian; Yan, Hanwei; Cheng, Beijiu

2014-01-01

Homeodomain leucine zipper I (HD-ZIP I) genes were used to increase the plasticity of plants by mediating external signals and regulating growth in response to environmental conditions. The way genomic histories drove the evolution of the HD-ZIP I family in legume species was described; HD-ZIP I genes were searched in Lotus japonicus, Medicago truncatula, Cajanus cajan and Phaseolus vulgaris, and then divided into five clades through phylogenetic analysis. Microsynteny analysis was made based on genomic segments containing the HD-ZIP I genes. Some pairs turned out to conform with syntenic genome regions, while others corresponded to those that were inverted, expanded, or contracted after the divergence of legumes. Besides, we dated their duplications by Ks analysis and demonstrated that all the blocks were formed after the monocot-dicot split; we observed Ka/Ks ratios representing strong purifying selections in the four legume species which might have been followed by gene loss and rearrangement. © 2014 Elsevier B.V. All rights reserved.

Genome-wide analysis and expression profile of the bZIP transcription factor gene family in grapevine (Vitis vinifera)

PubMed Central

2014-01-01

Background Basic leucine zipper (bZIP) transcription factor gene family is one of the largest and most diverse families in plants. Current studies have shown that the bZIP proteins regulate numerous growth and developmental processes and biotic and abiotic stress responses. Nonetheless, knowledge concerning the specific expression patterns and evolutionary history of plant bZIP family members remains very limited. Results We identified 55 bZIP transcription factor-encoding genes in the grapevine (Vitis vinifera) genome, and divided them into 10 groups according to the phylogenetic relationship with those in Arabidopsis. The chromosome distribution and the collinearity analyses suggest that expansion of the grapevine bZIP (VvbZIP) transcription factor family was greatly contributed by the segment/chromosomal duplications, which may be associated with the grapevine genome fusion events. Nine intron/exon structural patterns within the bZIP domain and the additional conserved motifs were identified among all VvbZIP proteins, and showed a high group-specificity. The predicted specificities on DNA-binding domains indicated that some highly conserved amino acid residues exist across each major group in the tree of land plant life. The expression patterns of VvbZIP genes across the grapevine gene expression atlas, based on microarray technology, suggest that VvbZIP genes are involved in grapevine organ development, especially seed development. Expression analysis based on qRT-PCR indicated that VvbZIP genes are extensively involved in drought- and heat-responses, with possibly different mechanisms. Conclusions The genome-wide identification, chromosome organization, gene structures, evolutionary and expression analyses of grapevine bZIP genes provide an overall insight of this gene family and their potential involvement in growth, development and stress responses. This will facilitate further research on the bZIP gene family regarding their evolutionary history and

A Petunia Homeodomain-Leucine Zipper Protein, PhHD-Zip, Plays an Important Role in Flower Senescence

PubMed Central

Chang, Xiaoxiao; Donnelly, Linda; Sun, Daoyang; Rao, Jingping; Reid, Michael S.; Jiang, Cai-Zhong

2014-01-01

Flower senescence is initiated by developmental and environmental signals, and regulated by gene transcription. A homeodomain-leucine zipper transcription factor, PhHD-Zip, is up-regulated during petunia flower senescence. Virus-induced gene silencing of PhHD-Zip extended flower life by 20% both in unpollinated and pollinated flowers. Silencing PhHD-Zip also dramatically reduced ethylene production and the abundance of transcripts of genes involved in ethylene (ACS, ACO), and ABA (NCED) biosynthesis. Abundance of transcripts of senescence-related genes (SAG12, SAG29) was also dramatically reduced in the silenced flowers. Over-expression of PhHD-Zip accelerated petunia flower senescence. Furthermore, PhHD-Zip transcript abundance in petunia flowers was increased by application of hormones (ethylene, ABA) and abiotic stresses (dehydration, NaCl and cold). Our results suggest that PhHD-Zip plays an important role in regulating petunia flower senescence. PMID:24551088

A Petunia homeodomain-leucine zipper protein, PhHD-Zip, plays an important role in flower senescence.

PubMed

Chang, Xiaoxiao; Donnelly, Linda; Sun, Daoyang; Rao, Jingping; Reid, Michael S; Jiang, Cai-Zhong

2014-01-01

Flower senescence is initiated by developmental and environmental signals, and regulated by gene transcription. A homeodomain-leucine zipper transcription factor, PhHD-Zip, is up-regulated during petunia flower senescence. Virus-induced gene silencing of PhHD-Zip extended flower life by 20% both in unpollinated and pollinated flowers. Silencing PhHD-Zip also dramatically reduced ethylene production and the abundance of transcripts of genes involved in ethylene (ACS, ACO), and ABA (NCED) biosynthesis. Abundance of transcripts of senescence-related genes (SAG12, SAG29) was also dramatically reduced in the silenced flowers. Over-expression of PhHD-Zip accelerated petunia flower senescence. Furthermore, PhHD-Zip transcript abundance in petunia flowers was increased by application of hormones (ethylene, ABA) and abiotic stresses (dehydration, NaCl and cold). Our results suggest that PhHD-Zip plays an important role in regulating petunia flower senescence.

Early memory formation disrupted by atypical PKC inhibitor ZIP in the medial prefrontal cortex but not hippocampus

PubMed Central

Evuarherhe, Obaro; Barker, Gareth R. I.; Savalli, Giorgia; Warburton, Elizabeth C.; Brown, Malcolm W.

2014-01-01

Atypical isoforms of protein kinase C (aPKCs; particularly protein kinase M zeta: PKMζ) have been hypothesised to be necessary and sufficient for the maintenance of long-term potentiation (LTP) and long term memory by maintaining postsynaptic AMPA receptors via the GluR2 subunit. A myristoylated PKMζ pseudosubstrate peptide (ZIP) blocks PKMζ activity. We examined the actions of ZIP in medial prefrontal cortex (mPFC) and hippocampus in associative recognition memory in rats during early memory formation and memory maintenance. ZIP infusion in either hippocampus or mPFC impaired memory maintenance. However, early memory formation was impaired by ZIP in mPFC but not hippocampus; and blocking GluR2-dependent removal of AMPA receptors did not affect this impairment caused by ZIP in the mPFC. The findings indicate: (i) a difference in the actions of ZIP in hippocampus and medial prefrontal cortex, and (ii) a GluR2-independent target of ZIP (possibly PKCλ) in the mPFC during early memory formation. PMID:24729442

Regular exercise and related factors in patients with Parkinson's disease: Applying zero-inflated negative binomial modeling of exercise count data.

PubMed

Lee, JuHee; Park, Chang Gi; Choi, Moonki

2016-05-01

This study was conducted to identify risk factors that influence regular exercise among patients with Parkinson's disease in Korea. Parkinson's disease is prevalent in the elderly, and may lead to a sedentary lifestyle. Exercise can enhance physical and psychological health. However, patients with Parkinson's disease are less likely to exercise than are other populations due to physical disability. A secondary data analysis and cross-sectional descriptive study were conducted. A convenience sample of 106 patients with Parkinson's disease was recruited at an outpatient neurology clinic of a tertiary hospital in Korea. Demographic characteristics, disease-related characteristics (including disease duration and motor symptoms), self-efficacy for exercise, balance, and exercise level were investigated. Negative binomial regression and zero-inflated negative binomial regression for exercise count data were utilized to determine factors involved in exercise. The mean age of participants was 65.85 ± 8.77 years, and the mean duration of Parkinson's disease was 7.23 ± 6.02 years. Most participants indicated that they engaged in regular exercise (80.19%). Approximately half of participants exercised at least 5 days per week for 30 min, as recommended (51.9%). Motor symptoms were a significant predictor of exercise in the count model, and self-efficacy for exercise was a significant predictor of exercise in the zero model. Severity of motor symptoms was related to frequency of exercise. Self-efficacy contributed to the probability of exercise. Symptom management and improvement of self-efficacy for exercise are important to encourage regular exercise in patients with Parkinson's disease. Copyright © 2015 Elsevier Inc. All rights reserved.

46 CFR 131.865 - Inflatable liferafts and inflatable buoyant apparatus.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Inflatable liferafts and inflatable buoyant apparatus... SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.865 Inflatable liferafts and inflatable buoyant apparatus. The number of the inflatable liferaft or inflatable buoyant...

46 CFR 131.865 - Inflatable liferafts and inflatable buoyant apparatus.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Inflatable liferafts and inflatable buoyant apparatus... SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.865 Inflatable liferafts and inflatable buoyant apparatus. The number of the inflatable liferaft or inflatable buoyant...

Tryptophan-dependent auxin biosynthesis is required for HD-ZIP III-mediated xylem patterning.

PubMed

Ursache, Robertas; Miyashima, Shunsuke; Chen, Qingguo; Vatén, Anne; Nakajima, Keiji; Carlsbecker, Annelie; Zhao, Yunde; Helariutta, Ykä; Dettmer, Jan

2014-03-01

The development and growth of higher plants is highly dependent on the conduction of water and minerals throughout the plant by xylem vessels. In Arabidopsis roots the xylem is organized as an axis of cell files with two distinct cell fates: the central metaxylem and the peripheral protoxylem. During vascular development, high and low expression levels of the class III HD-ZIP transcription factors promote metaxylem and protoxylem identities, respectively. Protoxylem specification is determined by both mobile, ground tissue-emanating miRNA165/6 species, which downregulate, and auxin concentrated by polar transport, which promotes HD-ZIP III expression. However, the factors promoting high HD-ZIP III expression for metaxylem identity have remained elusive. We show here that auxin biosynthesis promotes HD-ZIP III expression and metaxylem specification. Several auxin biosynthesis genes are expressed in the outer layers surrounding the vascular tissue in Arabidopsis root and downregulation of HD-ZIP III expression accompanied by specific defects in metaxylem development is seen in auxin biosynthesis mutants, such as trp2-12, wei8 tar2 or a quintuple yucca mutant, and in plants treated with L-kynurenine, a pharmacological inhibitor of auxin biosynthesis. Some of the patterning defects can be suppressed by synthetically elevated HD-ZIP III expression. Taken together, our results indicate that polar auxin transport, which was earlier shown to be required for protoxylem formation, is not sufficient to establish a proper xylem axis but that root-based auxin biosynthesis is additionally required.

Characterization of zinc transport by divalent metal transporters of the ZIP family from the model legume medicago truncatula

USDA-ARS?s Scientific Manuscript database

To understand how plants from the Fabaceae family maintain zinc (Zn) homeostasis, we have characterized the kinetics of the Zn transporting proteins from the ZIP family of divalent metal transporters in the model legume Medicago truncatula. MtZIP1, MtZIP5, and MtZIP6 were the only members from this ...

Isolation and expression analysis of EcbZIP17 from different finger millet genotypes shows conserved nature of the gene.

PubMed

Chopperla, Ramakrishna; Singh, Sonam; Mohanty, Sasmita; Reddy, Nanja; Padaria, Jasdeep C; Solanke, Amolkumar U

2017-10-01

Basic leucine zipper (bZIP) transcription factors comprise one of the largest gene families in plants. They play a key role in almost every aspect of plant growth and development and also in biotic and abiotic stress tolerance. In this study, we report isolation and characterization of EcbZIP17 , a group B bZIP transcription factor from a climate smart cereal, finger millet ( Eleusine coracana L.). The genomic sequence of EcbZIP17 is 2662 bp long encompassing two exons and one intron with ORF of 1722 bp and peptide length of 573 aa. This gene is homologous to AtbZIP17 ( Arabidopsis ), ZmbZIP17 (maize) and OsbZIP60 (rice) which play a key role in endoplasmic reticulum (ER) stress pathway. In silico analysis confirmed the presence of basic leucine zipper (bZIP) and transmembrane (TM) domains in the EcbZIP17 protein. Allele mining of this gene in 16 different genotypes by Sanger sequencing revealed no variation in nucleotide sequence, including the 618 bp long intron. Expression analysis of EcbZIP17 under heat stress exhibited similar pattern of expression in all the genotypes across time intervals with highest upregulation after 4 h. The present study established the conserved nature of EcbZIP17 at nucleotide and expression level.

Selecting a distributional assumption for modelling relative densities of benthic macroinvertebrates

USGS Publications Warehouse

Gray, B.R.

2005-01-01

The selection of a distributional assumption suitable for modelling macroinvertebrate density data is typically challenging. Macroinvertebrate data often exhibit substantially larger variances than expected under a standard count assumption, that of the Poisson distribution. Such overdispersion may derive from multiple sources, including heterogeneity of habitat (historically and spatially), differing life histories for organisms collected within a single collection in space and time, and autocorrelation. Taken to extreme, heterogeneity of habitat may be argued to explain the frequent large proportions of zero observations in macroinvertebrate data. Sampling locations may consist of habitats defined qualitatively as either suitable or unsuitable. The former category may yield random or stochastic zeroes and the latter structural zeroes. Heterogeneity among counts may be accommodated by treating the count mean itself as a random variable, while extra zeroes may be accommodated using zero-modified count assumptions, including zero-inflated and two-stage (or hurdle) approaches. These and linear assumptions (following log- and square root-transformations) were evaluated using 9 years of mayfly density data from a 52 km, ninth-order reach of the Upper Mississippi River (n = 959). The data exhibited substantial overdispersion relative to that expected under a Poisson assumption (i.e. variance:mean ratio = 23 ??? 1), and 43% of the sampling locations yielded zero mayflies. Based on the Akaike Information Criterion (AIC), count models were improved most by treating the count mean as a random variable (via a Poisson-gamma distributional assumption) and secondarily by zero modification (i.e. improvements in AIC values = 9184 units and 47-48 units, respectively). Zeroes were underestimated by the Poisson, log-transform and square root-transform models, slightly by the standard negative binomial model but not by the zero-modified models (61%, 24%, 32%, 7%, and 0%, respectively

The effect of a major cigarette price change on smoking behavior in california: a zero-inflated negative binomial model.

PubMed

Sheu, Mei-Ling; Hu, Teh-Wei; Keeler, Theodore E; Ong, Michael; Sung, Hai-Yen

2004-08-01

The objective of this paper is to determine the price sensitivity of smokers in their consumption of cigarettes, using evidence from a major increase in California cigarette prices due to Proposition 10 and the Tobacco Settlement. The study sample consists of individual survey data from Behavioral Risk Factor Survey (BRFS) and price data from the Bureau of Labor Statistics between 1996 and 1999. A zero-inflated negative binomial (ZINB) regression model was applied for the statistical analysis. The statistical model showed that price did not have an effect on reducing the estimated prevalence of smoking. However, it indicated that among smokers the price elasticity was at the level of -0.46 and statistically significant. Since smoking prevalence is significantly lower than it was a decade ago, price increases are becoming less effective as an inducement for hard-core smokers to quit, although they may respond by decreasing consumption. For those who only smoke occasionally (many of them being young adults) price increases alone may not be an effective inducement to quit smoking. Additional underlying behavioral factors need to be identified so that more effective anti-smoking strategies can be developed.

46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2011 CFR

2011-10-01

... Inspection of Lifesaving Equipment § 122.730 Servicing of inflatable liferafts, inflatable buoyant apparatus... apparatus must be serviced at a facility specifically approved by the Commandant for the particular brand... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD...

46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

Code of Federal Regulations, 2010 CFR

2010-10-01

... Inspection of Lifesaving Equipment § 122.730 Servicing of inflatable liferafts, inflatable buoyant apparatus... apparatus must be serviced at a facility specifically approved by the Commandant for the particular brand... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD...

Crosstalk between Two bZIP Signaling Pathways Orchestrates Salt-Induced Metabolic Reprogramming in Arabidopsis Roots

PubMed Central

Hartmann, Laura; Pedrotti, Lorenzo; Weiste, Christoph; Fekete, Agnes; Schierstaedt, Jasper; Göttler, Jasmin; Kempa, Stefan; Krischke, Markus; Dietrich, Katrin; Mueller, Martin J.; Vicente-Carbajosa, Jesus; Hanson, Johannes; Dröge-Laser, Wolfgang

2015-01-01

Soil salinity increasingly causes crop losses worldwide. Although roots are the primary targets of salt stress, the signaling networks that facilitate metabolic reprogramming to induce stress tolerance are less understood than those in leaves. Here, a combination of transcriptomic and metabolic approaches was performed in salt-treated Arabidopsis thaliana roots, which revealed that the group S1 basic leucine zipper transcription factors bZIP1 and bZIP53 reprogram primary C- and N-metabolism. In particular, gluconeogenesis and amino acid catabolism are affected by these transcription factors. Importantly, bZIP1 expression reflects cellular stress and energy status in roots. In addition to the well-described abiotic stress response pathway initiated by the hormone abscisic acid (ABA) and executed by SnRK2 (Snf1-RELATED-PROTEIN-KINASE2) and AREB-like bZIP factors, we identify a structurally related ABA-independent signaling module consisting of SnRK1s and S1 bZIPs. Crosstalk between these signaling pathways recruits particular bZIP factor combinations to establish at least four distinct gene expression patterns. Understanding this signaling network provides a framework for securing future crop productivity. PMID:26276836

INFLATE: INFlate Landing Apparatus Technology

NASA Astrophysics Data System (ADS)

Koryanov, V. V. K.; Da-Poian, V. D. P.

2018-02-01

Our project, named INFLATE (INFlatable Landing Apparatus Technology), aims at reducing space landing risks and constraints and so optimizing space missions (reducing cost, mass, and risk and in the same time improving performance).

Zinc Transporter SLC39A7/ZIP7 Promotes Intestinal Epithelial Self-Renewal by Resolving ER Stress

PubMed Central

Ohashi, Wakana; Kimura, Shunsuke; Iwanaga, Toshihiko; Furusawa, Yukihiro; Irié, Tarou; Izumi, Hironori; Watanabe, Takashi; Hara, Takafumi; Ohara, Osamu; Koseki, Haruhiko; Sato, Toshiro; Robine, Sylvie; Mori, Hisashi; Hattori, Yuichi; Mishima, Kenji; Ohno, Hiroshi; Hase, Koji; Fukada, Toshiyuki

2016-01-01

Zinc transporters play a critical role in spatiotemporal regulation of zinc homeostasis. Although disruption of zinc homeostasis has been implicated in disorders such as intestinal inflammation and aberrant epithelial morphology, it is largely unknown which zinc transporters are responsible for the intestinal epithelial homeostasis. Here, we show that Zrt-Irt-like protein (ZIP) transporter ZIP7, which is highly expressed in the intestinal crypt, is essential for intestinal epithelial proliferation. Mice lacking Zip7 in intestinal epithelium triggered endoplasmic reticulum (ER) stress in proliferative progenitor cells, leading to significant cell death of progenitor cells. Zip7 deficiency led to the loss of Olfm4+ intestinal stem cells and the degeneration of post-mitotic Paneth cells, indicating a fundamental requirement for Zip7 in homeostatic intestinal regeneration. Taken together, these findings provide evidence for the importance of ZIP7 in maintenance of intestinal epithelial homeostasis through the regulation of ER function in proliferative progenitor cells and maintenance of intestinal stem cells. Therapeutic targeting of ZIP7 could lead to effective treatment of gastrointestinal disorders. PMID:27736879

A modified detector concept for SuperCDMS: The HiZIP and its charge performance

NASA Astrophysics Data System (ADS)

Page, Kedar Mohan

SuperCDMS is a leading direct dark matter search experiment which uses solid state detectors (Ge crystals) at milliKelvin temperatures to look for nuclear recoils caused by dark matter interactions in the detector. 'Weakly Interacting Massive Particles' (WIMPs) are the most favoured dark matter candidate particles. SuperCDMS, like many other direct dark matter search experiments, primarily looks for WIMPs. The measurement of both the ionization and the lattice vibration (phonon) signals from an interaction in the detector allow it to discriminate against electron recoils which are the main source of background for WIMP detection. SuperCDMS currently operates about 9 kgs worth of germanium detectors at the Soudan underground lab in northern Minnesota. In its next phase, SuperCDMS SNOLAB, it plans to use 100-200 kg of target mass (Ge) which would allow it to probe more of the interesting and unexplored parameter space for WIMPs predicted by theoretical models. The SuperCDMS Queen's Test Facility is a detector testing facility which is intended to serve detector testing and detector research and development purposes for the SuperCDMS experiment. A modified detector called the 'HiZIP' (Half-iZIP), which is reduced in complexity in comparison to the currently used iZIP (interleaved Z-sensitive Ionization and Phonon mediated) detectors, is studied in this thesis. The HiZIP detector design also serves to discriminate against background from multiple scatter events occurring close to the surfaces in a single detector. Studies carried out to compare the surface event leakage in the HiZIP detector using limited information from iZIP data taken at SuperCDMS test facility at UC Berkley produce a highly conservative upper limit of 5 out of 10,000 events at 90% confidence level. This upper limit is the best among many different HiZIP configurations that were investigated and is comparable to the upper limit calculated for an iZIP detector in the same way using the same data. A

N-terminal segments modulate the α-helical propensities of the intrinsically disordered basic regions of bZIP proteins.

PubMed

Das, Rahul K; Crick, Scott L; Pappu, Rohit V

2012-02-17

Basic region leucine zippers (bZIPs) are modular transcription factors that play key roles in eukaryotic gene regulation. The basic regions of bZIPs (bZIP-bRs) are necessary and sufficient for DNA binding and specificity. Bioinformatic predictions and spectroscopic studies suggest that unbound monomeric bZIP-bRs are uniformly disordered as isolated domains. Here, we test this assumption through a comparative characterization of conformational ensembles for 15 different bZIP-bRs using a combination of atomistic simulations and circular dichroism measurements. We find that bZIP-bRs have quantifiable preferences for α-helical conformations in their unbound monomeric forms. This helicity varies from one bZIP-bR to another despite a significant sequence similarity of the DNA binding motifs (DBMs). Our analysis reveals that intramolecular interactions between DBMs and eight-residue segments directly N-terminal to DBMs are the primary modulators of bZIP-bR helicities. We test the accuracy of this inference by designing chimeras of bZIP-bRs to have either increased or decreased overall helicities. Our results yield quantitative insights regarding the relationship between sequence and the degree of intrinsic disorder within bZIP-bRs, and might have general implications for other intrinsically disordered proteins. Understanding how natural sequence variations lead to modulation of disorder is likely to be important for understanding the evolution of specificity in molecular recognition through intrinsically disordered regions (IDRs). Copyright © 2011 Elsevier Ltd. All rights reserved.

A generalized Poisson and Poisson-Boltzmann solver for electrostatic environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisicaro, G., E-mail: giuseppe.fisicaro@unibas.ch; Goedecker, S.; Genovese, L.

2016-01-07

The computational study of chemical reactions in complex, wet environments is critical for applications in many fields. It is often essential to study chemical reactions in the presence of applied electrochemical potentials, taking into account the non-trivial electrostatic screening coming from the solvent and the electrolytes. As a consequence, the electrostatic potential has to be found by solving the generalized Poisson and the Poisson-Boltzmann equations for neutral and ionic solutions, respectively. In the present work, solvers for both problems have been developed. A preconditioned conjugate gradient method has been implemented for the solution of the generalized Poisson equation and themore » linear regime of the Poisson-Boltzmann, allowing to solve iteratively the minimization problem with some ten iterations of the ordinary Poisson equation solver. In addition, a self-consistent procedure enables us to solve the non-linear Poisson-Boltzmann problem. Both solvers exhibit very high accuracy and parallel efficiency and allow for the treatment of periodic, free, and slab boundary conditions. The solver has been integrated into the BigDFT and Quantum-ESPRESSO electronic-structure packages and will be released as an independent program, suitable for integration in other codes.« less

A generalized Poisson and Poisson-Boltzmann solver for electrostatic environments.

PubMed

Fisicaro, G; Genovese, L; Andreussi, O; Marzari, N; Goedecker, S

2016-01-07

The computational study of chemical reactions in complex, wet environments is critical for applications in many fields. It is often essential to study chemical reactions in the presence of applied electrochemical potentials, taking into account the non-trivial electrostatic screening coming from the solvent and the electrolytes. As a consequence, the electrostatic potential has to be found by solving the generalized Poisson and the Poisson-Boltzmann equations for neutral and ionic solutions, respectively. In the present work, solvers for both problems have been developed. A preconditioned conjugate gradient method has been implemented for the solution of the generalized Poisson equation and the linear regime of the Poisson-Boltzmann, allowing to solve iteratively the minimization problem with some ten iterations of the ordinary Poisson equation solver. In addition, a self-consistent procedure enables us to solve the non-linear Poisson-Boltzmann problem. Both solvers exhibit very high accuracy and parallel efficiency and allow for the treatment of periodic, free, and slab boundary conditions. The solver has been integrated into the BigDFT and Quantum-ESPRESSO electronic-structure packages and will be released as an independent program, suitable for integration in other codes.

Services provided by community pharmacies in Wayne County, Michigan: a comparison by ZIP code characteristics.

PubMed

Erickson, Steven R; Workman, Paul

2014-01-01

To document the availability of selected pharmacy services and out-of-pocket cost of medication throughout a diverse county in Michigan and to assess possible associations between availability of services and price of medication and characteristics of residents of the ZIP codes in which the pharmacies were located. Cross-sectional telephone survey of pharmacies coupled with ZIP code-level census data. 503 pharmacies throughout the 63 ZIP codes of Wayne County, MI. The out-of-pocket cost for a 30 days' supply of levothyroxine 50 mcg and brand-name atorvastatin (Lipitor-Pfizer) 20 mg, availability of discount generic drug programs, home delivery of medications, hours of pharmacy operation, and availability of pharmacy-based immunization services. Census data aggregated at the ZIP code level included race, annual household income, age, and number of residents per pharmacy. The overall results per ZIP code showed that the average cost for levothyroxine was $10.01 ± $2.29 and $140.45 + $14.70 for Lipitor. Per ZIP code, the mean (± SD) percentages of pharmacies offering discount generic drug programs was 66.9% ± 15.0%; home delivery of medications was 44.5% ± 22.7%; and immunization for influenza was 46.7% ± 24.3% of pharmacies. The mean (± SD) hours of operation per pharmacy per ZIP code was 67.0 ± 25.2. ZIP codes with higher household income as well as higher percentage of residents being white had lower levothyroxine price, greater percentage of pharmacies offering discount generic drug programs, more hours of operation per week, and more pharmacy-based immunization services. The cost of Lipitor was not associated with any ZIP code characteristic. Disparities in the cost of generic levothyroxine, the availability of services such as discount generic drug programs, hours of operation, and pharmacy-based immunization services are evident based on race and household income within this diverse metropolitan county.

Increasing the affinity of selective bZIP-binding peptides through surface residue redesign.

PubMed

Kaplan, Jenifer B; Reinke, Aaron W; Keating, Amy E

2014-07-01

The coiled-coil dimer is a prevalent protein interaction motif that is important for many cellular processes. The basic leucine-zipper (bZIP) transcription factors are one family of proteins for which coiled-coil mediated dimerization is essential for function, and misregulation of bZIPs can lead to disease states including cancer. This makes coiled coils attractive protein-protein interaction targets to disrupt using engineered molecules. Previous work designing peptides to compete with native coiled-coil interactions focused primarily on designing the core residues of the interface to achieve affinity and specificity. However, folding studies on the model bZIP GCN4 show that coiled-coil surface residues also contribute to binding affinity. Here we extend a prior study in which peptides were designed to bind tightly and specifically to representative members of each of 20 human bZIP families. These "anti-bZIP" peptides were designed with an emphasis on target-binding specificity, with contributions to design-target specificity and affinity engineered considering only the coiled-coil core residues. High-throughput testing using peptide arrays indicated many successes. We have now measured the binding affinities and specificities of anti-bZIPs that bind to FOS, XBP1, ATF6, and CREBZF in solution and tested whether redesigning the surface residues can increase design-target affinity. Incorporating residues that favor helix formation into the designs increased binding affinities in all cases, providing low-nanomolar binders of each target. However, changes in surface electrostatic interactions sometimes changed the binding specificity of the designed peptides. © 2014 The Protein Society.

Health Care Utilization and Expenditures Attributable to Cigar Smoking Among US Adults, 2000-2015.

PubMed

Wang, Yingning; Sung, Hai-Yen; Yao, Tingting; Lightwood, James; Max, Wendy

Cigar use in the United States is a growing public health concern because of its increasing popularity. We estimated health care utilization and expenditures attributable to cigar smoking among US adults aged ≥35. We analyzed data on 84 178 adults using the 2000, 2005, 2010, and 2015 National Health Interview Surveys. We estimated zero-inflated Poisson (ZIP) regression models on hospital nights, emergency department (ED) visits, physician visits, and home-care visits as a function of tobacco use status-current sole cigar smokers (ie, smoke cigars only), current poly cigar smokers (smoke cigars and smoke cigarettes or use smokeless tobacco), former sole cigar smokers (used to smoke cigars only), former poly cigar smokers (used to smoke cigars and smoke cigarettes or use smokeless tobacco), other tobacco users (ever smoked cigarettes and used smokeless tobacco but not cigars), and never tobacco users (never smoked cigars, smoked cigarettes, or used smokeless tobacco)-and other covariates. We calculated health care utilization attributable to current and former sole cigar smoking based on the estimated ZIP models, and then we calculated total health care expenditures attributable to cigar smoking. Current and former sole cigar smoking was associated with excess annual utilization of 72 137 hospital nights, 32 748 ED visits, and 420 118 home-care visits. Annual health care expenditures attributable to sole cigar smoking were $284 million ($625 per sole cigar smoker), and total annual health care expenditures attributable to sole and poly cigar smoking were $1.75 billion. Comprehensive tobacco control policies and interventions are needed to reduce cigar smoking and the associated health care burden.

Screening Adolescents in the Emergency Department for Weapon Carriage

PubMed Central

Cunningham, Rebecca M.; Resko, Stella M.; Harrison, Stephanie Roahen; Zimmerman, Marc; Stanley, Rachel; Chermack, Stephen T.; Walton, Maureen A.

2010-01-01

Objective To describe prevalence and correlates of past year weapon involvement among adolescents seeking care in an inner-city ED. Methods This cross-sectional study administered a computerized survey to all eligible adolescents (age 14–18), seven days a week seeking care in the ED over an 18 month period in an inner-city Level 1 ED. Validated measures were administered including measures of demographics, sexual activity, substance use, injury, violent behavior and weapon carriage/use. Results Adolescents (N=2069, 86% response rate) completed the computerized survey. 55% were female; 56.5% were African American. In the past year, 20% of adolescents reported knife/razor carriage, 7% reported gun carriage, and 6% pulled a knife/gun on someone; zero-inflated Poisson (ZIP) regression models were used to identify correlates of the occurrence and past year frequency of these weapon variables. Although gun carriage was more frequent among males, females were as likely to carry a knife or pull a weapon in the past year. Conclusions One fifth of all adolescent’s seeking care in this inner city ED have carried a weapon. Understanding weapon carriage among teens seeking ED care is a critical first step to future ED based injury prevention initiatives. PMID:20370746

Schrödinger-Poisson-Vlasov-Poisson correspondence

NASA Astrophysics Data System (ADS)

Mocz, Philip; Lancaster, Lachlan; Fialkov, Anastasia; Becerra, Fernando; Chavanis, Pierre-Henri

2018-04-01

The Schrödinger-Poisson equations describe the behavior of a superfluid Bose-Einstein condensate under self-gravity with a 3D wave function. As ℏ/m →0 , m being the boson mass, the equations have been postulated to approximate the collisionless Vlasov-Poisson equations also known as the collisionless Boltzmann-Poisson equations. The latter describe collisionless matter with a 6D classical distribution function. We investigate the nature of this correspondence with a suite of numerical test problems in 1D, 2D, and 3D along with analytic treatments when possible. We demonstrate that, while the density field of the superfluid always shows order unity oscillations as ℏ/m →0 due to interference and the uncertainty principle, the potential field converges to the classical answer as (ℏ/m )2. Thus, any dynamics coupled to the superfluid potential is expected to recover the classical collisionless limit as ℏ/m →0 . The quantum superfluid is able to capture rich phenomena such as multiple phase-sheets, shell-crossings, and warm distributions. Additionally, the quantum pressure tensor acts as a regularizer of caustics and singularities in classical solutions. This suggests the exciting prospect of using the Schrödinger-Poisson equations as a low-memory method for approximating the high-dimensional evolution of the Vlasov-Poisson equations. As a particular example we consider dark matter composed of ultralight axions, which in the classical limit (ℏ/m →0 ) is expected to manifest itself as collisionless cold dark matter.

Is there scale-dependent bias in single-field inflation?

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Putter, Roland; Doré, Olivier; Green, Daniel, E-mail: rdputter@caltech.edu, E-mail: Olivier.P.Dore@jpl.nasa.gov, E-mail: drgreen@cita.utoronto.ca

2015-10-01

Scale-dependent halo bias due to local primordial non-Gaussianity provides a strong test of single-field inflation. While it is universally understood that single-field inflation predicts negligible scale-dependent bias compared to current observational uncertainties, there is still disagreement on the exact level of scale-dependent bias at a level that could strongly impact inferences made from future surveys. In this paper, we clarify this confusion and derive in various ways that there is exactly zero scale-dependent bias in single-field inflation. Much of the current confusion follows from the fact that single-field inflation does predict a mode coupling of matter perturbations at the levelmore » of f{sub NL}{sup local}; ≈ −5/3, which naively would lead to scale-dependent bias. However, we show explicitly that this mode coupling cancels out when perturbations are evaluated at a fixed physical scale rather than fixed coordinate scale. Furthermore, we show how the absence of scale-dependent bias can be derived easily in any gauge. This result can then be incorporated into a complete description of the observed galaxy clustering, including the previously studied general relativistic terms, which are important at the same level as scale-dependent bias of order f{sub NL}{sup local} ∼ 1. This description will allow us to draw unbiased conclusions about inflation from future galaxy clustering data.« less

Genome-wide analysis of soybean HD-Zip gene family and expression profiling under salinity and drought treatments.

PubMed

Chen, Xue; Chen, Zhu; Zhao, Hualin; Zhao, Yang; Cheng, Beijiu; Xiang, Yan

2014-01-01

Homeodomain-leucine zipper (HD-Zip) proteins, a group of homeobox transcription factors, participate in various aspects of normal plant growth and developmental processes as well as environmental responses. To date, no overall analysis or expression profiling of the HD-Zip gene family in soybean (Glycine max) has been reported. An investigation of the soybean genome revealed 88 putative HD-Zip genes. These genes were classified into four subfamilies, I to IV, based on phylogenetic analysis. In each subfamily, the constituent parts of gene structure and motif were relatively conserved. A total of 87 out of 88 genes were distributed unequally on 20 chromosomes with 36 segmental duplication events, indicating that segmental duplication is important for the expansion of the HD-Zip family. Analysis of the Ka/Ks ratios showed that the duplicated genes of the HD-Zip family basically underwent purifying selection with restrictive functional divergence after the duplication events. Analysis of expression profiles showed that 80 genes differentially expressed across 14 tissues, and 59 HD-Zip genes are differentially expressed under salinity and drought stress, with 20 paralogous pairs showing nearly identical expression patterns and three paralogous pairs diversifying significantly under drought stress. Quantitative real-time RT-PCR (qRT-PCR) analysis of six paralogous pairs of 12 selected soybean HD-Zip genes under both drought and salinity stress confirmed their stress-inducible expression patterns. This study presents a thorough overview of the soybean HD-Zip gene family and provides a new perspective on the evolution of this gene family. The results indicate that HD-Zip family genes may be involved in many plant responses to stress conditions. Additionally, this study provides a solid foundation for uncovering the biological roles of HD-Zip genes in soybean growth and development.

Genome-Wide Analysis of Soybean HD-Zip Gene Family and Expression Profiling under Salinity and Drought Treatments

PubMed Central

Chen, Xue; Chen, Zhu; Zhao, Hualin; Zhao, Yang; Cheng, Beijiu; Xiang, Yan

2014-01-01

Background Homeodomain-leucine zipper (HD-Zip) proteins, a group of homeobox transcription factors, participate in various aspects of normal plant growth and developmental processes as well as environmental responses. To date, no overall analysis or expression profiling of the HD-Zip gene family in soybean (Glycine max) has been reported. Methods and Findings An investigation of the soybean genome revealed 88 putative HD-Zip genes. These genes were classified into four subfamilies, I to IV, based on phylogenetic analysis. In each subfamily, the constituent parts of gene structure and motif were relatively conserved. A total of 87 out of 88 genes were distributed unequally on 20 chromosomes with 36 segmental duplication events, indicating that segmental duplication is important for the expansion of the HD-Zip family. Analysis of the Ka/Ks ratios showed that the duplicated genes of the HD-Zip family basically underwent purifying selection with restrictive functional divergence after the duplication events. Analysis of expression profiles showed that 80 genes differentially expressed across 14 tissues, and 59 HD-Zip genes are differentially expressed under salinity and drought stress, with 20 paralogous pairs showing nearly identical expression patterns and three paralogous pairs diversifying significantly under drought stress. Quantitative real-time RT-PCR (qRT-PCR) analysis of six paralogous pairs of 12 selected soybean HD-Zip genes under both drought and salinity stress confirmed their stress-inducible expression patterns. Conclusions This study presents a thorough overview of the soybean HD-Zip gene family and provides a new perspective on the evolution of this gene family. The results indicate that HD-Zip family genes may be involved in many plant responses to stress conditions. Additionally, this study provides a solid foundation for uncovering the biological roles of HD-Zip genes in soybean growth and development. PMID:24498296

The Inflatable Poster

NASA Astrophysics Data System (ADS)

Tackley, P. J.

2004-12-01

Inflatable devices are frequently used in advertising in order to grab the attention of consumers: one sees, for example, 20 foot tall inflatable drink containers, inflatable cell phones, inflatable bubble gum packets, as well as blimps wafting majestically over major sports events. More usefully, inflatable representations of scientifically-interesting items are widely available, including astronauts, space shuttles, dinosaurs and globes and can help to build and inspire the interest of the general public, and in particular children, in such ideas. How can such concepts be adapted to improve poster presentations? Possibility one is to use relevant existing commercially-available inflatables to dress the poster: skeletons, astronauts, globes and so forth. More exciting is to develop custom inflatables that represent three-dimensional renderings of objects that the poster is describing. Examples of individual objects might be an inflatable slab, inflatable avalanche, inflatable plume, or it's larger cousin, the 10 foot high inflatable superplume or 20 foot high inflatable megaplume. More elaborately, inflatables might represent isosurfaces in three-dimensional spherical convection, although other fabrication methods may be more suitable. More simply, inflatable spheres could be imprinted with the planform of convection, geoid, or other spherical fields of geophysical interest. Finally, it should be possible to put an entire poster on an inflatable object, possibly small ones (balloons) to hand out. A major concern, however, is that the presenter may use such techniques to inflate their scientific findings, or to present overblown ideas.

Multi-material Additive Manufacturing of Metamaterials with Giant, Tailorable Negative Poisson's Ratios.

PubMed

Chen, Da; Zheng, Xiaoyu

2018-06-14

Nature has evolved with a recurring strategy to achieve unusual mechanical properties through coupling variable elastic moduli from a few GPa to below KPa within a single tissue. The ability to produce multi-material, three-dimensional (3D) micro-architectures with high fidelity incorporating dissimilar components has been a major challenge in man-made materials. Here we show multi-modulus metamaterials whose architectural element is comprised of encoded elasticity ranging from rigid to soft. We found that, in contrast to ordinary architected materials whose negative Poisson's ratio is dictated by their geometry, these type of metamaterials are capable of displaying Poisson's ratios from extreme negative to zero, independent of their 3D micro-architecture. The resulting low density metamaterials is capable of achieving functionally graded, distributed strain amplification capabilities within the metamaterial with uniform micro-architectures. Simultaneous tuning of Poisson's ratio and moduli within the 3D multi-materials could open up a broad array of material by design applications ranging from flexible armor, artificial muscles, to actuators and bio-mimetic materials.

Inflation and dark energy from f(R) gravity

NASA Astrophysics Data System (ADS)

Artymowski, Michał; Lalak, Zygmunt

2014-09-01

The standard Starobinsky inflation has been extended to the R + α Rn - β R2-n model to obtain a stable minimum of the Einstein frame scalar potential of the auxiliary field. As a result we have obtained obtain a scalar potential with non-zero value of residual vacuum energy, which may be a source of Dark Energy. Our results can be easily consistent with PLANCK or BICEP2 data for appropriate choices of the value of n.

Genome Wide Identification of Orthologous ZIP Genes Associated with Zinc and Iron Translocation in Setaria italica.

PubMed

Alagarasan, Ganesh; Dubey, Mahima; Aswathy, Kumar S; Chandel, Girish

2017-01-01

Genes in the ZIP family encode transcripts to store and transport bivalent metal micronutrient, particularly iron (Fe) and or zinc (Zn). These transcripts are important for a variety of functions involved in the developmental and physiological processes in many plant species, including most, if not all, Poaceae plant species and the model species Arabidopsis. Here, we present the report of a genome wide investigation of orthologous ZIP genes in Setaria italica and the identification of 7 single copy genes. RT-PCR shows 4 of them could be used to increase the bio-availability of zinc and iron content in grains. Of 36 ZIP members, 25 genes have traces of signal peptide based sub-cellular localization, as compared to those of plant species studied previously, yet translocation of ions remains unclear. In silico analysis of gene structure and protein nature suggests that these two were preeminent in shaping the functional diversity of the ZIP gene family in S. italica . NAC, bZIP and bHLH are the predominant Fe and Zn responsive transcription factors present in SiZIP genes. Together, our results provide new insights into the signal peptide based/independent iron and zinc translocation in the plant system and allowed identification of ZIP genes that may be involved in the zinc and iron absorption from the soil, and thus transporting it to the cereal grain underlying high micronutrient accumulation.

Soft inflation

NASA Technical Reports Server (NTRS)

Berkin, Andrew L.; Maeda, Kei-Ichi; Yokoyama, Junichi

1990-01-01

The cosmology resulting from two coupled scalar fields was studied, one which is either a new inflation or chaotic type inflation, and the other which has an exponentially decaying potential. Such a potential may appear in the conformally transformed frame of generalized Einstein theories like the Jordan-Brans-Dicke theory. The constraints necessary for successful inflation are examined. Conventional GUT models such as SU(5) were found to be compatible with new inflation, while restrictions on the self-coupling constant are significantly loosened for chaotic inflation.

Nambu-Poisson gauge theory

NASA Astrophysics Data System (ADS)

Jurčo, Branislav; Schupp, Peter; Vysoký, Jan

2014-06-01

We generalize noncommutative gauge theory using Nambu-Poisson structures to obtain a new type of gauge theory with higher brackets and gauge fields. The approach is based on covariant coordinates and higher versions of the Seiberg-Witten map. We construct a covariant Nambu-Poisson gauge theory action, give its first order expansion in the Nambu-Poisson tensor and relate it to a Nambu-Poisson matrix model.

Low-Mass Inflation Systems for Inflatable Structures

NASA Technical Reports Server (NTRS)

Thunnissen, Daniel P.; Webster, Mark S.; Engelbrecht, Carl S.

1995-01-01

The use of inflatable space structures has often been proposed for aerospace and planetary applications. Communication, power generation, and very-long-baseline interferometry are just three potential applications of inflatable technology. The success of inflatable structures depends on the development of an applications of inflatable technology. This paper describes two design studies performed to develop a low mass inflation system. The first study takes advantage of existing onboard propulsion gases to reduce the overall system mass. The second study assumes that there is no onboard propulsion system. Both studies employ advanced components developed for the Pluto fast flyby spacecraft to further reduce mass. The study examined four different types of systems: hydrazine, nitrogen and water, nitrogen, and xenon. This study shows that all of these systems can be built for a small space structure with masses lower than 0.5 kilograms.

The Zinc Transporter Zip5 (Slc39a5) Regulates Intestinal Zinc Excretion and Protects the Pancreas against Zinc Toxicity

PubMed Central

Geiser, Jim; De Lisle, Robert C.; Andrews, Glen K.

2013-01-01

Background ZIP5 localizes to the baso-lateral membranes of intestinal enterocytes and pancreatic acinar cells and is internalized and degraded coordinately in these cell-types during periods of dietary zinc deficiency. These cell-types are thought to control zinc excretion from the body. The baso-lateral localization and zinc-regulation of ZIP5 in these cells are unique among the 14 members of the Slc39a family and suggest that ZIP5 plays a role in zinc excretion. Methods/Principal Findings We created mice with floxed Zip5 genes and deleted this gene in the entire mouse or specifically in enterocytes or acinar cells and then examined the effects on zinc homeostasis. We found that ZIP5 is not essential for growth and viability but total knockout of ZIP5 led to increased zinc in the liver in mice fed a zinc-adequate (ZnA) diet but impaired accumulation of pancreatic zinc in mice fed a zinc-excess (ZnE) diet. Loss-of-function of enterocyte ZIP5, in contrast, led to increased pancreatic zinc in mice fed a ZnA diet and increased abundance of intestinal Zip4 mRNA. Finally, loss-of-function of acinar cell ZIP5 modestly reduced pancreatic zinc in mice fed a ZnA diet but did not impair zinc uptake as measured by the rapid accumulation of 67zinc. Retention of pancreatic 67zinc was impaired in these mice but the absence of pancreatic ZIP5 sensitized them to zinc-induced pancreatitis and exacerbated the formation of large cytoplasmic vacuoles containing secretory protein in acinar cells. Conclusions These studies demonstrate that ZIP5 participates in the control of zinc excretion in mice. Specifically, they reveal a paramount function of intestinal ZIP5 in zinc excretion but suggest a role for pancreatic ZIP5 in zinc accumulation/retention in acinar cells. ZIP5 functions in acinar cells to protect against zinc-induced acute pancreatitis and attenuate the process of zymophagy. This suggests that it may play a role in autophagy. PMID:24303081

OsbZIP58, a basic leucine zipper transcription factor, regulates starch biosynthesis in rice endosperm.

PubMed

Wang, Jie-Chen; Xu, Heng; Zhu, Ying; Liu, Qiao-Quan; Cai, Xiu-Ling

2013-08-01

Starch composition and the amount in endosperm, both of which contribute dramatically to seed yield, cooking quality, and taste in cereals, are determined by a series of complex biochemical reactions. However, the mechanism regulating starch biosynthesis in cereal seeds is not well understood. This study showed that OsbZIP58, a bZIP transcription factor, is a key transcriptional regulator controlling starch synthesis in rice endosperm. OsbZIP58 was expressed mainly in endosperm during active starch synthesis. osbzip58 null mutants displayed abnormal seed morphology with altered starch accumulation in the white belly region and decreased amounts of total starch and amylose. Moreover, osbzip58 had a higher proportion of short chains and a lower proportion of intermediate chains of amylopectin. Furthermore, OsbZIP58 was shown to bind directly to the promoters of six starch-synthesizing genes, OsAGPL3, Wx, OsSSIIa, SBE1, OsBEIIb, and ISA2, and to regulate their expression. These findings indicate that OsbZIP58 functions as a key regulator of starch synthesis in rice seeds and provide new insights into seed quality control.

The prion-ZIP connection: From cousins to partners in iron uptake

PubMed Central

Singh, Neena; Asthana, Abhishek; Baksi, Shounak; Desai, Vilok; Haldar, Swati; Hari, Sahi; Tripathi, Ajai K

2015-01-01

ABSTRACT Converging observations from disparate lines of inquiry are beginning to clarify the cause of brain iron dyshomeostasis in sporadic Creutzfeldt-Jakob disease (sCJD), a neurodegenerative condition associated with the conversion of prion protein (PrPC), a plasma membrane glycoprotein, from α-helical to a β-sheet rich PrP-scrapie (PrPSc) isoform. Biochemical evidence indicates that PrPC facilitates cellular iron uptake by functioning as a membrane-bound ferrireductase (FR), an activity necessary for the transport of iron across biological membranes through metal transporters. An entirely different experimental approach reveals an evolutionary link between PrPC and the Zrt, Irt-like protein (ZIP) family, a group of proteins involved in the transport of zinc, iron, and manganese across the plasma membrane. Close physical proximity of PrPC with certain members of the ZIP family on the plasma membrane and increased uptake of extracellular iron by cells that co-express PrPC and ZIP14 suggest that PrPC functions as a FR partner for certain members of this family. The connection between PrPC and ZIP proteins therefore extends beyond common ancestry to that of functional cooperation. Here, we summarize evidence supporting the facilitative role of PrPC in cellular iron uptake, and implications of this activity on iron metabolism in sCJD brains. PMID:26689487

Memory Retrieval Has a Dynamic Influence on the Maintenance Mechanisms That Are Sensitive to ζ-Inhibitory Peptide (ZIP).

PubMed

Levitan, David; Fortis-Santiago, Yaihara; Figueroa, Joshua A; Reid, Emily E; Yoshida, Takashi; Barry, Nicholas C; Russo, Abigail; Katz, Donald B

2016-10-12

In neuroscientists' attempts to understand the long-term storage of memory, topics of particular importance and interest are the cellular and system mechanisms of maintenance (e.g., those sensitive to ζ-inhibitory peptide, ZIP) and those induced by memory retrieval (i.e., reconsolidation). Much is known about each of these processes in isolation, but less is known concerning how they interact. It is known that ZIP sensitivity and memory retrieval share at least some molecular targets (e.g., recycling α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, AMPA, receptors to the plasma membrane); conversely, the fact that sensitivity to ZIP emerges only after consolidation ends suggests that consolidation (and by extension reconsolidation) and maintenance might be mutually exclusive processes, the onset of one canceling the other. Here, we use conditioned taste aversion (CTA) in rats, a cortically dependent learning paradigm, to test this hypothesis. First, we demonstrate that ZIP infusions into gustatory cortex begin interfering with CTA memory 43-45 h after memory acquisition-after consolidation ends. Next, we show that a retrieval trial administered after this time point interrupts the ability of ZIP to induce amnesia and that ZIP's ability to induce amnesia is reengaged only 45 h after retrieval. This pattern of results suggests that memory retrieval and ZIP-sensitive maintenance mechanisms are mutually exclusive and that the progression from one to the other are similar after acquisition and retrieval. They also reveal concrete differences between ZIP-sensitive mechanisms induced by acquisition and retrieval: the latency with which ZIP-sensitive mechanisms are expressed differ for the two processes. Memory retrieval and the molecular mechanisms that are sensitive to ζ-inhibitory peptide (ZIP) are the few manipulations that have been shown to effect memory maintenance. Although much is known about their effect on maintenance separately, it is unknown how they

First-order inflation

NASA Technical Reports Server (NTRS)

Kolb, Edward W.

1991-01-01

In the original proposal, inflation occurred in the process of a strongly first-order phase transition. This model was soon demonstrated to be fatally flawed. Subsequent models for inflation involved phase transitions that were second-order, or perhaps weakly first-order; some even involved no phase transition at all. Recently the possibility of inflation during a strongly first-order phase transition has been revived. In this talk I will discuss some models for first-order inflation, and emphasize unique signatures that result if inflation is realized in a first-order transition. Before discussing first-order inflation, I will briefly review some of the history of inflation to demonstrate how first-order inflation differs from other models.

Species abundance in a forest community in South China: A case of poisson lognormal distribution

USGS Publications Warehouse

Yin, Z.-Y.; Ren, H.; Zhang, Q.-M.; Peng, S.-L.; Guo, Q.-F.; Zhou, G.-Y.

2005-01-01

Case studies on Poisson lognormal distribution of species abundance have been rare, especially in forest communities. We propose a numerical method to fit the Poisson lognormal to the species abundance data at an evergreen mixed forest in the Dinghushan Biosphere Reserve, South China. Plants in the tree, shrub and herb layers in 25 quadrats of 20 m??20 m, 5 m??5 m, and 1 m??1 m were surveyed. Results indicated that: (i) for each layer, the observed species abundance with a similarly small median, mode, and a variance larger than the mean was reverse J-shaped and followed well the zero-truncated Poisson lognormal; (ii) the coefficient of variation, skewness and kurtosis of abundance, and two Poisson lognormal parameters (?? and ??) for shrub layer were closer to those for the herb layer than those for the tree layer; and (iii) from the tree to the shrub to the herb layer, the ?? and the coefficient of variation decreased, whereas diversity increased. We suggest that: (i) the species abundance distributions in the three layers reflects the overall community characteristics; (ii) the Poisson lognormal can describe the species abundance distribution in diverse communities with a few abundant species but many rare species; and (iii) 1/?? should be an alternative measure of diversity.

Genome-wide analysis of the basic leucine zipper (bZIP) transcription factor gene family in six legume genomes.

PubMed

Wang, Zhihui; Cheng, Ke; Wan, Liyun; Yan, Liying; Jiang, Huifang; Liu, Shengyi; Lei, Yong; Liao, Boshou

2015-12-10

Plant bZIP proteins characteristically harbor a highly conserved bZIP domain with two structural features: a DNA-binding basic region and a leucine (Leu) zipper dimerization region. They have been shown to be diverse transcriptional regulators, playing crucial roles in plant development, physiological processes, and biotic/abiotic stress responses. Despite the availability of six completely sequenced legume genomes, a comprehensive investigation of bZIP family members in legumes has yet to be presented. In this study, we identified 428 bZIP genes encoding 585 distinct proteins in six legumes, Glycine max, Medicago truncatula, Phaseolus vulgaris, Cicer arietinum, Cajanus cajan, and Lotus japonicus. The legume bZIP genes were categorized into 11 groups according to their phylogenetic relationships with genes from Arabidopsis. Four kinds of intron patterns (a-d) within the basic and hinge regions were defined and additional conserved motifs were identified, both presenting high group specificity and supporting the group classification. We predicted the DNA-binding patterns and the dimerization properties, based on the characteristic features in the basic and hinge regions and the Leu zipper, respectively, which indicated that some highly conserved amino acid residues existed across each major group. The chromosome distribution and analysis for WGD-derived duplicated blocks revealed that the legume bZIP genes have expanded mainly by segmental duplication rather than tandem duplication. Expression data further revealed that the legume bZIP genes were expressed constitutively or in an organ-specific, development-dependent manner playing roles in multiple seed developmental stages and tissues. We also detected several key legume bZIP genes involved in drought- and salt-responses by comparing fold changes of expression values in drought-stressed or salt-stressed roots and leaves. In summary, this genome-wide identification, characterization and expression analysis of

Estimation of inflation parameters for Perturbed Power Law model using recent CMB measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukherjee, Suvodip; Das, Santanu; Souradeep, Tarun

2015-01-01

Cosmic Microwave Background (CMB) is an important probe for understanding the inflationary era of the Universe. We consider the Perturbed Power Law (PPL) model of inflation which is a soft deviation from Power Law (PL) inflationary model. This model captures the effect of higher order derivative of Hubble parameter during inflation, which in turn leads to a non-zero effective mass m{sub eff} for the inflaton field. The higher order derivatives of Hubble parameter at leading order sources constant difference in the spectral index for scalar and tensor perturbation going beyond PL model of inflation. PPL model have two observable independentmore » parameters, namely spectral index for tensor perturbation ν{sub t} and change in spectral index for scalar perturbation ν{sub st} to explain the observed features in the scalar and tensor power spectrum of perturbation. From the recent measurements of CMB power spectra by WMAP, Planck and BICEP-2 for temperature and polarization, we estimate the feasibility of PPL model with standard ΛCDM model. Although BICEP-2 claimed a detection of r=0.2, estimates of dust contamination provided by Planck have left open the possibility that only upper bound on r will be expected in a joint analysis. As a result we consider different upper bounds on the value of r and show that PPL model can explain a lower value of tensor to scalar ratio (r<0.1 or r<0.01) for a scalar spectral index of n{sub s}=0.96 by having a non-zero value of effective mass of the inflaton field m{sup 2}{sub eff}/H{sup 2}. The analysis with WP + Planck likelihood shows a non-zero detection of m{sup 2}{sub eff}/H{sup 2} with 5.7 σ and 8.1 σ respectively for r<0.1 and r<0.01. Whereas, with BICEP-2 likelihood m{sup 2}{sub eff}/H{sup 2} = −0.0237 ± 0.0135 which is consistent with zero.« less

Estimation of inflation parameters for Perturbed Power Law model using recent CMB measurements

NASA Astrophysics Data System (ADS)

Mukherjee, Suvodip; Das, Santanu; Joy, Minu; Souradeep, Tarun

2015-01-01

Cosmic Microwave Background (CMB) is an important probe for understanding the inflationary era of the Universe. We consider the Perturbed Power Law (PPL) model of inflation which is a soft deviation from Power Law (PL) inflationary model. This model captures the effect of higher order derivative of Hubble parameter during inflation, which in turn leads to a non-zero effective mass meff for the inflaton field. The higher order derivatives of Hubble parameter at leading order sources constant difference in the spectral index for scalar and tensor perturbation going beyond PL model of inflation. PPL model have two observable independent parameters, namely spectral index for tensor perturbation νt and change in spectral index for scalar perturbation νst to explain the observed features in the scalar and tensor power spectrum of perturbation. From the recent measurements of CMB power spectra by WMAP, Planck and BICEP-2 for temperature and polarization, we estimate the feasibility of PPL model with standard ΛCDM model. Although BICEP-2 claimed a detection of r=0.2, estimates of dust contamination provided by Planck have left open the possibility that only upper bound on r will be expected in a joint analysis. As a result we consider different upper bounds on the value of r and show that PPL model can explain a lower value of tensor to scalar ratio (r<0.1 or r<0.01) for a scalar spectral index of ns=0.96 by having a non-zero value of effective mass of the inflaton field m2eff/H2. The analysis with WP + Planck likelihood shows a non-zero detection of m2eff/H2 with 5.7 σ and 8.1 σ respectively for r<0.1 and r<0.01. Whereas, with BICEP-2 likelihood m2eff/H2 = -0.0237 ± 0.0135 which is consistent with zero.

Systematic Analysis of Sequences and Expression Patterns of Drought-Responsive Members of the HD-Zip Gene Family in Maize

PubMed Central

Zhao, Yang; Zhou, Yuqiong; Jiang, Haiyang; Li, Xiaoyu; Gan, Defang; Peng, Xiaojian; Zhu, Suwen; Cheng, Beijiu

2011-01-01

Background Members of the homeodomain-leucine zipper (HD-Zip) gene family encode transcription factors that are unique to plants and have diverse functions in plant growth and development such as various stress responses, organ formation and vascular development. Although systematic characterization of this family has been carried out in Arabidopsis and rice, little is known about HD-Zip genes in maize (Zea mays L.). Methods and Findings In this study, we described the identification and structural characterization of HD-Zip genes in the maize genome. A complete set of 55 HD-Zip genes (Zmhdz1-55) were identified in the maize genome using Blast search tools and categorized into four classes (HD-Zip I-IV) based on phylogeny. Chromosomal location of these genes revealed that they are distributed unevenly across all 10 chromosomes. Segmental duplication contributed largely to the expansion of the maize HD-ZIP gene family, while tandem duplication was only responsible for the amplification of the HD-Zip II genes. Furthermore, most of the maize HD-Zip I genes were found to contain an overabundance of stress-related cis-elements in their promoter sequences. The expression levels of the 17 HD-Zip I genes under drought stress were also investigated by quantitative real-time PCR (qRT-PCR). All of the 17 maize HD-ZIP I genes were found to be regulated by drought stress, and the duplicated genes within a sister pair exhibited the similar expression patterns, suggesting their conserved functions during the process of evolution. Conclusions Our results reveal a comprehensive overview of the maize HD-Zip gene family and provide the first step towards the selection of Zmhdz genes for cloning and functional research to uncover their roles in maize growth and development. PMID:22164299

Systematic analysis of sequences and expression patterns of drought-responsive members of the HD-Zip gene family in maize.

PubMed

Zhao, Yang; Zhou, Yuqiong; Jiang, Haiyang; Li, Xiaoyu; Gan, Defang; Peng, Xiaojian; Zhu, Suwen; Cheng, Beijiu

2011-01-01

Members of the homeodomain-leucine zipper (HD-Zip) gene family encode transcription factors that are unique to plants and have diverse functions in plant growth and development such as various stress responses, organ formation and vascular development. Although systematic characterization of this family has been carried out in Arabidopsis and rice, little is known about HD-Zip genes in maize (Zea mays L.). In this study, we described the identification and structural characterization of HD-Zip genes in the maize genome. A complete set of 55 HD-Zip genes (Zmhdz1-55) were identified in the maize genome using Blast search tools and categorized into four classes (HD-Zip I-IV) based on phylogeny. Chromosomal location of these genes revealed that they are distributed unevenly across all 10 chromosomes. Segmental duplication contributed largely to the expansion of the maize HD-ZIP gene family, while tandem duplication was only responsible for the amplification of the HD-Zip II genes. Furthermore, most of the maize HD-Zip I genes were found to contain an overabundance of stress-related cis-elements in their promoter sequences. The expression levels of the 17 HD-Zip I genes under drought stress were also investigated by quantitative real-time PCR (qRT-PCR). All of the 17 maize HD-ZIP I genes were found to be regulated by drought stress, and the duplicated genes within a sister pair exhibited the similar expression patterns, suggesting their conserved functions during the process of evolution. Our results reveal a comprehensive overview of the maize HD-Zip gene family and provide the first step towards the selection of Zmhdz genes for cloning and functional research to uncover their roles in maize growth and development.

Comparative Genomic Analysis of slc39a12/ZIP12: Insight into a Zinc Transporter Required for Vertebrate Nervous System Development

PubMed Central

Chowanadisai, Winyoo

2014-01-01

The zinc transporter ZIP12, which is encoded by the gene slc39a12, has previously been shown to be important for neuronal differentiation in mouse Neuro-2a neuroblastoma cells and primary mouse neurons and necessary for neurulation during Xenopus tropicalis embryogenesis. However, relatively little is known about the biochemical properties, cellular regulation, or the physiological role of this gene. The hypothesis that ZIP12 is a zinc transporter important for nervous system function and development guided a comparative genetics approach to uncover the presence of ZIP12 in various genomes and identify conserved sequences and expression patterns associated with ZIP12. Ortholog detection of slc39a12 was conducted with reciprocal BLAST hits with the amino acid sequence of human ZIP12 in comparison to the human paralog ZIP4 and conserved local synteny between genomes. ZIP12 is present in the genomes of almost all vertebrates examined, from humans and other mammals to most teleost fish. However, ZIP12 appears to be absent from the zebrafish genome. The discrimination of ZIP12 compared to ZIP4 was unsuccessful or inconclusive in other invertebrate chordates and deuterostomes. Splice variation, due to the inclusion or exclusion of a conserved exon, is present in humans, rats, and cows and likely has biological significance. ZIP12 also possesses many putative di-leucine and tyrosine motifs often associated with intracellular trafficking, which may control cellular zinc uptake activity through the localization of ZIP12 within the cell. These findings highlight multiple aspects of ZIP12 at the biochemical, cellular, and physiological levels with likely biological significance. ZIP12 appears to have conserved function as a zinc uptake transporter in vertebrate nervous system development. Consequently, the role of ZIP12 may be an important link to reported congenital malformations in numerous animal models and humans that are caused by zinc deficiency. PMID:25375179

Inflatable Structures Technology Handbook. Chapter 21; Inflatable Habitats

NASA Technical Reports Server (NTRS)

Kennedy, Kriss J.; Raboin, Jasen; Spexarth, Gary; Valle, Gerard

2000-01-01

The technologies required to design, fabricate, and utilize an inflatable module for space applications has been demonstrated and proven by the TransHab team during the development phase of the program. Through testing and hands-on development several issues about inflatable space structures have been addressed , such as: ease of manufacturing, structural integrity, micrometeorite protection, folding , and vacuum deployment. The TransHab inflatable technology development program has proven that not only are inflatable structures a viable option, but they also offer significant advantages over conventional metallic structures.

Cosmic Inflation

ScienceCinema

Lincoln, Don

2018-01-16

In 1964, scientists discovered a faint radio hiss coming from the heavens and realized that the hiss wasn’t just noise. It was a message from eons ago; specifically the remnants of the primordial fireball, cooled to about 3 degrees above absolute zero. Subsequent research revealed that the radio hiss was the same in every direction. The temperature of the early universe was uniform to at better than a part in a hundred thousand. And this was weird. According to the prevailing theory, the two sides of the universe have never been in contact. So how could two places that had never been in contact be so similar? One possible explanation was proposed in 1979. Called inflation, the theory required that early in the history of the universe, the universe expanded faster than the speed of light. Confused? Watch this video as Fermilab’s Dr. Don Lincoln makes sense of this mind-bending idea.

Cosmic Inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, Don

In 1964, scientists discovered a faint radio hiss coming from the heavens and realized that the hiss wasn’t just noise. It was a message from eons ago; specifically the remnants of the primordial fireball, cooled to about 3 degrees above absolute zero. Subsequent research revealed that the radio hiss was the same in every direction. The temperature of the early universe was uniform to at better than a part in a hundred thousand. And this was weird. According to the prevailing theory, the two sides of the universe have never been in contact. So how could two places that hadmore » never been in contact be so similar? One possible explanation was proposed in 1979. Called inflation, the theory required that early in the history of the universe, the universe expanded faster than the speed of light. Confused? Watch this video as Fermilab’s Dr. Don Lincoln makes sense of this mind-bending idea.« less

Genome-wide analyses of the bZIP family reveal their involvement in the development, ripening and abiotic stress response in banana

PubMed Central

Hu, Wei; Wang, Lianzhe; Tie, Weiwei; Yan, Yan; Ding, Zehong; Liu, Juhua; Li, Meiying; Peng, Ming; Xu, Biyu; Jin, Zhiqiang

2016-01-01

The leucine zipper (bZIP) transcription factors play important roles in multiple biological processes. However, less information is available regarding the bZIP family in the important fruit crop banana. In this study, 121 bZIP transcription factor genes were identified in the banana genome. Phylogenetic analysis showed that MabZIPs were classified into 11 subfamilies. The majority of MabZIP genes in the same subfamily shared similar gene structures and conserved motifs. The comprehensive transcriptome analysis of two banana genotypes revealed the differential expression patterns of MabZIP genes in different organs, in various stages of fruit development and ripening, and in responses to abiotic stresses, including drought, cold, and salt. Interaction networks and co-expression assays showed that group A MabZIP-mediated networks participated in various stress signaling, which was strongly activated in Musa ABB Pisang Awak. This study provided new insights into the complicated transcriptional control of MabZIP genes and provided robust tissue-specific, development-dependent, and abiotic stress-responsive candidate MabZIP genes for potential applications in the genetic improvement of banana cultivars. PMID:27445085

Interleukin-6 regulates the zinc transporter Zip14 in liver and contributes to the hypozincemia of the acute-phase response

PubMed Central

Liuzzi, Juan P.; Lichten, Louis A.; Rivera, Seth; Blanchard, Raymond K.; Aydemir, Tolunay Beker; Knutson, Mitchell D.; Ganz, Tomas; Cousins, Robert J.

2005-01-01

Infection and inflammation produce systemic responses that include hypozincemia and hypoferremia. The latter involves regulation of the iron transporter ferroportin 1 by hepcidin. The mechanism of reduced plasma zinc is not known. Transcripts of the two zinc transporter gene families (ZnT and Zip) were screened for regulation in mouse liver after turpentine-induced inflammation and LPS administration. Zip14 mRNA was the transporter transcript most up-regulated by inflammation and LPS. IL-6 knockout (IL-6–/–) mice did not exhibit either hypozincemia or the induction of Zip14 with turpentine inflammation. However, in IL-6–/– mice, LPS produced a milder hypozincemic response but no Zip14 induction. Northern analysis showed Zip14 up-regulation was specific for the liver, with one major transcript. Immunohistochemistry, using an antibody to an extracellular Zip14 epitope, showed both LPS and turpentine increased abundance of Zip14 at the plasma membrane of hepatocytes. IL-6 produced increased expression of Zip14 in primary hepatocytes cultures and localization of the protein to the plasma membrane. Transfection of mZip14 cDNA into human embryonic kidney cells increased zinc uptake as measured by both a fluorescent probe for free Zn2+ and 65Zn accumulation, as well as by metallothionein mRNA induction, all indicating that Zip14 functions as a zinc importer. Zip14 was localized in plasma membrane of the transfected cells. These in vivo and in vitro experiments demonstrate that Zip14 expression is up-regulated through IL-6, and that this zinc transporter most likely plays a major role in the mechanism responsible for hypozincemia that accompanies the acute-phase response to inflammation and infection. PMID:15863613

Evaluation of the Use of Zero-Augmented Regression Techniques to Model Incidence of Campylobacter Infections in FoodNet.

PubMed

Tremblay, Marlène; Crim, Stacy M; Cole, Dana J; Hoekstra, Robert M; Henao, Olga L; Döpfer, Dörte

2017-10-01

The Foodborne Diseases Active Surveillance Network (FoodNet) is currently using a negative binomial (NB) regression model to estimate temporal changes in the incidence of Campylobacter infection. FoodNet active surveillance in 483 counties collected data on 40,212 Campylobacter cases between years 2004 and 2011. We explored models that disaggregated these data to allow us to account for demographic, geographic, and seasonal factors when examining changes in incidence of Campylobacter infection. We hypothesized that modeling structural zeros and including demographic variables would increase the fit of FoodNet's Campylobacter incidence regression models. Five different models were compared: NB without demographic covariates, NB with demographic covariates, hurdle NB with covariates in the count component only, hurdle NB with covariates in both zero and count components, and zero-inflated NB with covariates in the count component only. Of the models evaluated, the nonzero-augmented NB model with demographic variables provided the best fit. Results suggest that even though zero inflation was not present at this level, individualizing the level of aggregation and using different model structures and predictors per site might be required to correctly distinguish between structural and observational zeros and account for risk factors that vary geographically.

Feedback Regulation of ABA Signaling and Biosynthesis by a bZIP Transcription Factor Targets Drought-Resistance-Related Genes1[OPEN

PubMed Central

Tang, Ning; Yang, Jun; Peng, Lei; Ma, Siqi; Xu, Yan; Li, Guoliang

2016-01-01

The OsbZIP23 transcription factor has been characterized for its essential role in drought resistance in rice (Oryza sativa), but the mechanism is unknown. In this study, we first investigated the transcriptional activation of OsbZIP23. A homolog of SnRK2 protein kinase (SAPK2) was found to interact with and phosphorylate OsbZIP23 for its transcriptional activation. SAPK2 also interacted with OsPP2C49, an ABI1 homolog, which deactivated the SAPK2 to inhibit the transcriptional activation activity of OsbZIP23. Next, we performed genome-wide identification of OsbZIP23 targets by immunoprecipitation sequencing and RNA sequencing analyses in the OsbZIP23-overexpression, osbzip23 mutant, and wild-type rice under normal and drought stress conditions. OsbZIP23 directly regulates a large number of reported genes that function in stress response, hormone signaling, and developmental processes. Among these targets, we found that OsbZIP23 could positively regulate OsPP2C49, and overexpression of OsPP2C49 in rice resulted in significantly decreased sensitivity of the abscisic acid (ABA) response and rapid dehydration. Moreover, OsNCED4 (9-cis-epoxycarotenoid dioxygenase4), a key gene in ABA biosynthesis, was also positively regulated by OsbZIP23. Together, our results suggest that OsbZIP23 acts as a central regulator in ABA signaling and biosynthesis, and drought resistance in rice. PMID:27325665

Anisotropic inflation with a non-minimally coupled electromagnetic field to gravity

NASA Astrophysics Data System (ADS)

Adak, Muzaffer; Akarsu, Özgür; Dereli, Tekin; Sert, Özcan

2017-11-01

We consider the non-minimal model of gravity in Y(R) F2-form. We investigate a particular case of the model, for which the higher order derivatives are eliminated but the scalar curvature R is kept to be dynamical via the constraint YRFmnFmn =-2/κ2. The effective fluid obtained can be represented by interacting electromagnetic field and vacuum depending on Y(R), namely, the energy density of the vacuum tracks R while energy density of the conventional electromagnetic field is dynamically scaled with the factor Y(R)/2. We give exact solutions for anisotropic inflation by assuming the volume scale factor of the Universe exhibits a power-law expansion. The directional scale factors do not necessarily exhibit power-law expansion, which would give rise to a constant expansion anisotropy, but expand non-trivially and give rise to a non-monotonically evolving expansion anisotropy that eventually converges to a non-zero constant. Relying on this fact, we discuss the anisotropic e-fold during the inflation by considering observed scale invariance in CMB and demanding the Universe to undergo the same amount of e-folds in all directions. We calculate the residual expansion anisotropy at the end of inflation, though as a result of non-monotonic behaviour of expansion anisotropy all the axes of the Universe undergo the same of amount of e-folds by the end of inflation. We also discuss the generation of the modified electromagnetic field during the first few e-folds of the inflation and its persistence against to the vacuum till end of inflation.

Tobit analysis of vehicle accident rates on interstate highways.

PubMed

Anastasopoulos, Panagiotis Ch; Tarko, Andrew P; Mannering, Fred L

2008-03-01

There has been an abundance of research that has used Poisson models and its variants (negative binomial and zero-inflated models) to improve our understanding of the factors that affect accident frequencies on roadway segments. This study explores the application of an alternate method, tobit regression, by viewing vehicle accident rates directly (instead of frequencies) as a continuous variable that is left-censored at zero. Using data from vehicle accidents on Indiana interstates, the estimation results show that many factors relating to pavement condition, roadway geometrics and traffic characteristics significantly affect vehicle accident rates.

LiZIP3 is a cellular zinc transporter that mediates the tightly regulated import of zinc in Leishmania infantum parasites

PubMed Central

Carvalho, Sandra; da Silva, Rosa Barreira; Shawki, Ali; Castro, Helena; Lamy, Márcia; Eide, David; Costa, Vítor; Mackenzie, Bryan; Tomás, Ana M.

2016-01-01

Summary Cellular zinc homeostasis ensures that the intracellular concentration of this element is kept within limits that enable its participation in critical physiological processes without exerting toxic effects. We report here the identification and characterization of the first mediator of zinc homeostasis in Leishmania infantum, LiZIP3, a member of the ZIP family of divalent metal-ion transporters. The zinc transporter activity of LiZIP3 was first disclosed by its capacity to rescue the growth of Saccharomyces cerevisiae strains deficient in zinc acquisition. Subsequent expression of LiZIP3 in Xenopus laevis oocytes was shown to stimulate the uptake of a broad range of metal ions, among which Zn2+ was the preferred LiZIP3 substrate (K0.5 ≈ 0.1 μM). Evidence that LiZIP3 functions as a zinc importer in L. infantum came from the observations that the protein locates to the cell membrane and that its overexpression leads to augmented zinc internalization. Importantly, expression and cell-surface location of LiZIP3 are lost when parasites face high zinc bioavailability. LiZIP3 decline in response to zinc is regulated at the mRNA level in a process involving (a) short-lived protein(s). Collectively, our data reveal that LiZIP3 enables L. infantum to acquire zinc in a highly regulated manner, hence contributing to zinc homeostasis. PMID:25644708

A basic leucine zipper transcription factor, AabZIP1, connects abscisic acid signaling with artemisinin biosynthesis in Artemisia annua.

PubMed

Zhang, Fangyuan; Fu, Xueqing; Lv, Zongyou; Lu, Xu; Shen, Qian; Zhang, Ling; Zhu, Mengmeng; Wang, Guofeng; Sun, Xiaofen; Liao, Zhihua; Tang, Kexuan

2015-01-01

Artemisinin is a sesquiterpenoid especially synthesized in the Chinese herbal plant, Artemisia annua, which is widely used in the treatment of malaria. Artemisinin accumulation can be enhanced by exogenous abscisic acid (ABA) treatment. However, it is not known how ABA signaling regulates artemisinin biosynthesis. A global expression profile and phylogenetic analysis as well as the dual-LUC screening revealed that a basic leucine zipper family transcription factor from A. annua (namely AabZIP1) was involved in ABA signaling to regulate artemisinin biosynthesis. AabZIP1 had a higher expression level in the inflorescences than in other tissues; ABA treatment, drought, and salt stress strongly induced the expression of AabZIP1. Yeast one-hybrid assay and electrophoretic mobility shift assay (EMSA) showed that AabZIP1 bound to the ABA-responsive elements (ABRE) in the promoter regions of the amorpha-4,11-diene synthase (ADS) gene and CYP71AV1, which are two key structural genes of the artemisinin biosynthetic pathway. A mutagenesis assay showed that the C1 domain in the N-terminus of AabZIP1 was important for its transactivation activity. Furthermore, the activation of ADS and CYP71AV1 promoters by AabZIP1 was enhanced by ABA treatment in transient dual-LUC analysis. The AabZIP1 variant with C1 domain deletion lost the ability to activate ADS and CYP71AV1 promoters regardless of ABA treatment. Notably, overexpression of AabZIP1 in A. annua resulted in significantly increased accumulation of artemisinin. Our results indicate that ABA promotes artemisinin biosynthesis, likely through 1 activation of ADS and CYP71AV1 expression by AabZIP in A. annua. Meanwhile, our findings reveal the potential value of AabZIP1 in genetic engineering of artemisinin production. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

PSD-Zip70 Deficiency Causes Prefrontal Hypofunction Associated with Glutamatergic Synapse Maturation Defects by Dysregulation of Rap2 Activity.

PubMed

Mayanagi, Taira; Yasuda, Hiroki; Sobue, Kenji

2015-10-21

Dysregulation of synapse formation and plasticity is closely related to the pathophysiology of psychiatric and neurodevelopmental disorders. The prefrontal cortex (PFC) is particularly important for executive functions such as working memory, cognition, and emotional control, which are impaired in the disorders. PSD-Zip70 (Lzts1/FEZ1) is a postsynaptic density (PSD) protein predominantly expressed in the frontal cortex, olfactory bulb, striatum, and hippocampus. Here we found that PSD-Zip70 knock-out (PSD-Zip70KO) mice exhibit working memory and cognitive defects, and enhanced anxiety-like behaviors. These abnormal behaviors are caused by impaired glutamatergic synapse transmission accompanied by tiny-headed immature dendritic spines in the PFC, due to aberrant Rap2 activation, which has roles in synapse formation and plasticity. PSD-Zip70 modulates the Rap2 activity by interacting with SPAR (spine-associated RapGAP) and PDZ-GEF1 (RapGEF) in the postsynapse. Furthermore, suppression of the aberrant Rap2 activation in the PFC rescued the behavioral defects in PSD-Zip70KO mice. Our data demonstrate a critical role for PSD-Zip70 in Rap2-dependent spine synapse development in the PFC and underscore the importance of this regulation in PFC-dependent behaviors. PSD-Zip70 deficiency causes behavioral defects in working memory and cognition, and enhanced anxiety due to prefrontal hypofunction. This study revealed that PSD-Zip70 plays essential roles in glutamatergic synapse maturation via modulation of the Rap2 activity in the PFC. PSD-Zip70 interacts with both SPAR (spine-associated RapGAP) and PDZ-GEF1 (RapGEF) and modulates the Rap2 activity in postsynaptic sites. Our results provide a novel Rap2-specific regulatory mechanism in synaptic maturation involving PSD-Zip70. Copyright © 2015 the authors 0270-6474/15/3514327-14$15.00/0.

Fractional Poisson Fields and Martingales

NASA Astrophysics Data System (ADS)

Aletti, Giacomo; Leonenko, Nikolai; Merzbach, Ely

2018-02-01

We present new properties for the Fractional Poisson process (FPP) and the Fractional Poisson field on the plane. A martingale characterization for FPPs is given. We extend this result to Fractional Poisson fields, obtaining some other characterizations. The fractional differential equations are studied. We consider a more general Mixed-Fractional Poisson process and show that this process is the stochastic solution of a system of fractional differential-difference equations. Finally, we give some simulations of the Fractional Poisson field on the plane.

Estimating the Depth of the Navy Recruiting Market

DTIC Science & Technology

2016-09-01

recommend that NRC make use of the Poisson regression model in order to determine high-yield ZIP codes for market depth. 14. SUBJECT...recommend that NRC make use of the Poisson regression model in order to determine high-yield ZIP codes for market depth. vi THIS PAGE INTENTIONALLY LEFT...DEPTH OF THE NAVY RECRUITING MARKET by Emilie M. Monaghan September 2016 Thesis Advisor: Lyn R. Whitaker Second Reader: Jonathan K. Alt

Fitting statistical distributions to sea duck count data: implications for survey design and abundance estimation

USGS Publications Warehouse

Zipkin, Elise F.; Leirness, Jeffery B.; Kinlan, Brian P.; O'Connell, Allan F.; Silverman, Emily D.

2014-01-01

Determining appropriate statistical distributions for modeling animal count data is important for accurate estimation of abundance, distribution, and trends. In the case of sea ducks along the U.S. Atlantic coast, managers want to estimate local and regional abundance to detect and track population declines, to define areas of high and low use, and to predict the impact of future habitat change on populations. In this paper, we used a modified marked point process to model survey data that recorded flock sizes of Common eiders, Long-tailed ducks, and Black, Surf, and White-winged scoters. The data come from an experimental aerial survey, conducted by the United States Fish & Wildlife Service (USFWS) Division of Migratory Bird Management, during which east-west transects were flown along the Atlantic Coast from Maine to Florida during the winters of 2009–2011. To model the number of flocks per transect (the points), we compared the fit of four statistical distributions (zero-inflated Poisson, zero-inflated geometric, zero-inflated negative binomial and negative binomial) to data on the number of species-specific sea duck flocks that were recorded for each transect flown. To model the flock sizes (the marks), we compared the fit of flock size data for each species to seven statistical distributions: positive Poisson, positive negative binomial, positive geometric, logarithmic, discretized lognormal, zeta and Yule–Simon. Akaike’s Information Criterion and Vuong’s closeness tests indicated that the negative binomial and discretized lognormal were the best distributions for all species for the points and marks, respectively. These findings have important implications for estimating sea duck abundances as the discretized lognormal is a more skewed distribution than the Poisson and negative binomial, which are frequently used to model avian counts; the lognormal is also less heavy-tailed than the power law distributions (e.g., zeta and Yule–Simon), which are

On a Poisson homogeneous space of bilinear forms with a Poisson-Lie action

NASA Astrophysics Data System (ADS)

Chekhov, L. O.; Mazzocco, M.

2017-12-01

Let \\mathscr A be the space of bilinear forms on C^N with defining matrices A endowed with a quadratic Poisson structure of reflection equation type. The paper begins with a short description of previous studies of the structure, and then this structure is extended to systems of bilinear forms whose dynamics is governed by the natural action A\\mapsto B ABT} of the {GL}_N Poisson-Lie group on \\mathscr A. A classification is given of all possible quadratic brackets on (B, A)\\in {GL}_N× \\mathscr A preserving the Poisson property of the action, thus endowing \\mathscr A with the structure of a Poisson homogeneous space. Besides the product Poisson structure on {GL}_N× \\mathscr A, there are two other (mutually dual) structures, which (unlike the product Poisson structure) admit reductions by the Dirac procedure to a space of bilinear forms with block upper triangular defining matrices. Further generalisations of this construction are considered, to triples (B,C, A)\\in {GL}_N× {GL}_N× \\mathscr A with the Poisson action A\\mapsto B ACT}, and it is shown that \\mathscr A then acquires the structure of a Poisson symmetric space. Generalisations to chains of transformations and to the quantum and quantum affine algebras are investigated, as well as the relations between constructions of Poisson symmetric spaces and the Poisson groupoid. Bibliography: 30 titles.

Golden alga presence and abundance are inversely related to salinity in a high-salinity river ecosystem, Pecos River, USA

USGS Publications Warehouse

Israël, Natascha M.D.; VanLandeghem, Matthew M.; Denny, Shawn; Ingle, John; Patino, Reynaldo

2014-01-01

Prymnesium parvum (golden alga, GA) is a toxigenic harmful alga native to marine ecosystems that has also affected brackish inland waters. The first toxic bloom of GA in the western hemisphere occurred in the Pecos River, one of the saltiest rivers in North America. Environmental factors (water quality) associated with GA occurrence in this basin, however, have not been examined. Water quality and GA presence and abundance were determined at eight sites in the Pecos River basin with or without prior history of toxic blooms. Sampling was conducted monthly from January 2012 to July 2013. Specific conductance (salinity) varied spatiotemporally between 4408 and 73,786 mS/cm. Results of graphical, principal component (PCA), and zero-inflated Poisson (ZIP) regression analyses indicated that the incidence and abundance of GA are reduced as salinity increases spatiotemporally. LOWESS regression and correlation analyses of archived data for specific conductance and GA abundance at one of the study sites retrospectively confirmed the negative association between these variables. Results of PCA also suggested that at <15,000 mS/cm, GA was present at a relatively wide range of nutrient (nitrogen and phosphorus) concentrations whereas at higher salinity, GA was observed only at mid-to-high nutrient levels. Generally consistent with earlier studies, results of ZIP regression indicated that GA presence is positively associated with organic phosphorus and in samples where GA is present, GA abundance is positively associated with organic nitrogen and negatively associated with inorganic nitrogen. This is the first report of an inverse relation between salinity and GA presence and abundance in riverine waters and of interaction effects of salinity and nutrients in the field. These observations contribute to a more complete understanding of environmental conditions that influence GA distribution in inland waters.

Understanding poisson regression.

PubMed

Hayat, Matthew J; Higgins, Melinda

2014-04-01

Nurse investigators often collect study data in the form of counts. Traditional methods of data analysis have historically approached analysis of count data either as if the count data were continuous and normally distributed or with dichotomization of the counts into the categories of occurred or did not occur. These outdated methods for analyzing count data have been replaced with more appropriate statistical methods that make use of the Poisson probability distribution, which is useful for analyzing count data. The purpose of this article is to provide an overview of the Poisson distribution and its use in Poisson regression. Assumption violations for the standard Poisson regression model are addressed with alternative approaches, including addition of an overdispersion parameter or negative binomial regression. An illustrative example is presented with an application from the ENSPIRE study, and regression modeling of comorbidity data is included for illustrative purposes. Copyright 2014, SLACK Incorporated.

Adiabatic elimination for systems with inertia driven by compound Poisson colored noise.

PubMed

Li, Tiejun; Min, Bin; Wang, Zhiming

2014-02-01

We consider the dynamics of systems driven by compound Poisson colored noise in the presence of inertia. We study the limit when the frictional relaxation time and the noise autocorrelation time both tend to zero. We show that the Itô and Marcus stochastic calculuses naturally arise depending on these two time scales, and an extra intermediate type occurs when the two time scales are comparable. This leads to three different limiting regimes which are supported by numerical simulations. Furthermore, we establish that when the resulting compound Poisson process tends to the Wiener process in the frequent jump limit the Itô and Marcus calculuses, respectively, tend to the classical Itô and Stratonovich calculuses for Gaussian white noise, and the crossover type calculus tends to a crossover between the Itô and Stratonovich calculuses. Our results would be very helpful for understanding relevant experiments when jump type noise is involved.

Temperature of the inflaton and duration of inflation from Wilkinson microwave anisotropy probe data.

PubMed

Bhattacharya, Kaushik; Mohanty, Subhendra; Rangarajan, Raghavan

2006-03-31

If the initial state of the inflaton field is taken to have a thermal distribution instead of the conventional zero particle vacuum state then the curvature power spectrum gets modified by a temperature dependent factor such that the fluctuation spectrum of the microwave background radiation is enhanced at larger angles. We compare this modified cosmic microwave background spectrum with Wilkinson microwave anisotropy probe data to obtain an upper bound on the temperature of the inflaton at the time our current horizon crossed the horizon during inflation. We further conclude that there must be additional -foldings of inflation beyond what is needed to solve the horizon problem.

Pseudosmooth tribrid inflation

NASA Astrophysics Data System (ADS)

Antusch, Stefan; Nolde, David; Rehman, Mansoor Ur

2012-08-01

We explore a new class of supersymmetric models of inflation where the inflaton is realised as a combination of a Higgs field and (gauge non-singlet) matter fields, using a ``tribrid'' structure of the superpotential. Inflation is associated with a phase transition around GUT scale energies. The inflationary trajectory already preselects the later vacuum after inflation, which has the advantage of automatically avoiding the production of dangerous topological defects at the end of inflation. While at first sight the models look similar to smooth inflation, they feature a waterfall and are therefore only pseudosmooth. The new class of models offers novel possibilities for realising inflation in close contact with particle physics, for instance with supersymmetric GUTs or with supersymmetric flavour models based on family symmetries.

Zip Pak (Boys) for Third Reader Level.

ERIC Educational Resources Information Center

Scott, Norval C., Comp.

Aim of the Zip Pak is to improve the migrant child's interest in reading. Behavioral objectives are to have the migrant child indicate 10 percent happier faces on the posttest; to have an equal number of blame-self, blame-others on the posttest; and to have 25 percent more praise-self on the posttest. The workbook for boys includes a story about…

What is the cause of confidence inflation in the Life Events Inventory (LEI) paradigm?

PubMed

Von Glahn, Nicholas R; Otani, Hajime; Migita, Mai; Langford, Sara J; Hillard, Erin E

2012-01-01

Briefly imagining, paraphrasing, or explaining an event causes people to increase their confidence that this event occurred during childhood-the imagination inflation effect. The mechanisms responsible for the effect were investigated with a new paradigm. In Experiment 1, event familiarity (defined as processing fluency) was varied by asking participants to rate each event once, three times, or five times. No inflation was found, indicating that familiarity does not account for the effect. In Experiment 2, richness of memory representation was manipulated by asking participants to generate zero, three, or six details. Confidence increased from the initial to the final rating in the three- and six-detail conditions, indicating that the effect is based on reality-monitoring errors. However, greater inflation in the three-detail condition than in the six-detail condition indicated that there is a boundary condition. These results were also consistent with an alternative hypothesis, the mental workload hypothesis.

Screening adolescents in the emergency department for weapon carriage.

PubMed

Cunningham, Rebecca M; Resko, Stella M; Harrison, Stephanie Roahen; Zimmerman, Marc; Stanley, Rachel; Chermack, Stephen T; Walton, Maureen A

2010-02-01

The objective was to describe the prevalence and correlates of past-year weapon involvement among adolescents seeking care in an inner-city emergency department (ED). This cross-sectional study administered a computerized survey to all eligible adolescents (age 14-18 years), 7 days a week, who were seeking care over an 18-month period at an inner-city Level 1 ED. Validated measures were administered, including measures of demographics, sexual activity, substance use, injury, violent behavior, weapon carriage, and/or weapon use. Zero-inflated Poisson (ZIP) regression models were used to identify correlates of the occurrence and past-year frequency of these weapons variables. Adolescents (n = 2069, 86% response rate) completed the computerized survey. Fifty-five percent were female; 56.5% were African American. In the past year, 20% of adolescents reported knife or razor carriage, 7% reported gun carriage, and 6% pulled a knife or gun on someone. Although gun carriage was more frequent among males, females were as likely to carry a knife or pull a weapon in the past year. One-fifth of all adolescents seeking care in this inner-city ED have carried a weapon. Understanding weapon carriage among teens seeking ED care is a critical first step to future ED-based injury prevention initiatives. (c) 2010 by the Society for Academic Emergency Medicine.

Attention Deficit Hyperactivity Disorder symptoms and smoking trajectories: race and gender differences.

PubMed

Lee, Chien-Ti; Clark, Trenette T; Kollins, Scott H; McClernon, F Joseph; Fuemmeler, Bernard F

2015-03-01

This study examined the influence of Attention Deficit Hyperactivity Disorder (ADHD) symptoms severity and directionality (hyperactive-impulsive symptoms relative to inattentive symptoms) on trajectories of the probability of current (past month) smoking and the number of cigarettes smoked from age 13 to 32. Racial and gender differences in the relationship of ADHD symptoms and smoking trajectories were also assessed. A subsample of 9719 youth (54.5% female) was drawn from the National Longitudinal Study of Adolescent to Adult Health (Add Health). Cohort sequential design and zero-inflated Poisson (ZIP) latent growth modeling were used to estimate the relationship between ADHD directionality and severity on smoking development. ADHD severity's effect on the likelihood of ever smoking cigarettes at the intercept (age 13) had a greater impact on White males than other groups. ADHD severity also had a stronger influence on the initial number of cigarettes smoked at age 13 among Hispanic participants. The relationships between ADHD directionality (hyperactive-impulsive symptoms relative to inattentive symptoms) and a higher number of cigarettes smoked at the intercept were stronger among Hispanic males than others. Gender differences manifested only among Whites. ADHD severity and directionality had unique effects on smoking trajectories. Our results also highlight that the risk of ADHD symptoms may differ by race and gender. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Conditional mouse models support the role of SLC39A14 (ZIP14) in Hyperostosis Cranialis Interna and in bone homeostasis

PubMed Central

Steenackers, Ellen; Yorgan, Timur A.; Hermans, Christophe; Boudin, Eveline; Waterval, Jérôme J.; Jansen, Ineke D. C.; Aydemir, Tolunay Beker; Kamerling, Niels; Plumeyer, Christine; D’Haese, Patrick C.; Everts, Vincent; Lammens, Martin; Mortier, Geert; Cousins, Robert J.; Schinke, Thorsten; Stokroos, Robert J.; Manni, Johannes J.; Van Hul, Wim

2018-01-01

Hyperostosis Cranialis Interna (HCI) is a rare bone disorder characterized by progressive intracranial bone overgrowth at the skull. Here we identified by whole-exome sequencing a dominant mutation (L441R) in SLC39A14 (ZIP14). We show that L441R ZIP14 is no longer trafficked towards the plasma membrane and excessively accumulates intracellular zinc, resulting in hyper-activation of cAMP-CREB and NFAT signaling. Conditional knock-in mice overexpressing L438R Zip14 in osteoblasts have a severe skeletal phenotype marked by a drastic increase in cortical thickness due to an enhanced endosteal bone formation, resembling the underlying pathology in HCI patients. Remarkably, L438R Zip14 also generates an osteoporotic trabecular bone phenotype. The effects of osteoblastic overexpression of L438R Zip14 therefore mimic the disparate actions of estrogen on cortical and trabecular bone through osteoblasts. Collectively, we reveal ZIP14 as a novel regulator of bone homeostasis, and that manipulating ZIP14 might be a therapeutic strategy for bone diseases. PMID:29621230

Molecular cloning and characterization of a tomato cDNA encoding a systemically wound-inducible bZIP DNA-binding protein

NASA Technical Reports Server (NTRS)

Stankovic, B.; Vian, A.; Henry-Vian, C.; Davies, E.

2000-01-01

Localized wounding of one leaf in intact tomato (Lycopersicon esculentum Mill.) plants triggers rapid systemic transcriptional responses that might be involved in defense. To better understand the mechanism(s) of intercellular signal transmission in wounded tomatoes, and to identify the array of genes systemically up-regulated by wounding, a subtractive cDNA library for wounded tomato leaves was constructed. A novel cDNA clone (designated LebZIP1) encoding a DNA-binding protein was isolated and identified. This clone appears to be encoded by a single gene, and belongs to the family of basic leucine zipper domain (bZIP) transcription factors shown to be up-regulated by cold and dark treatments. Analysis of the mRNA levels suggests that the transcript for LebZIP1 is both organ-specific and up-regulated by wounding. In wounded wild-type tomatoes, the LebZIP1 mRNA levels in distant tissue were maximally up-regulated within only 5 min following localized wounding. Exogenous abscisic acid (ABA) prevented the rapid wound-induced increase in LebZIP1 mRNA levels, while the basal levels of LebZIP1 transcripts were higher in the ABA mutants notabilis (not), sitiens (sit), and flacca (flc), and wound-induced increases were greater in the ABA-deficient mutants. Together, these results suggest that ABA acts to curtail the wound-induced synthesis of LebZIP1 mRNA.

Distinguishing between extra natural inflation and natural inflation after BICEP2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohri, Kazunori; Lim, C.S.; Lin, Chia-Min, E-mail: kohri@post.kek.jp, E-mail: lim@lab.twcu.ac.jp, E-mail: lin@chuo-u.ac.jp

2014-08-01

In this paper, we carefully calculated the tensor-to-scalar ratio, the running spectral index, and the running of running spectrum for (extra) natural inflation in order to compare with recent BICEP2 data, PLANCK satellite data and future 21 cm data. We discovered that the prediction for running spectral index and the running of running spectrum in natural inflation is different from that in the case of extra natural inflation. Near future observation for the running spectral index can only provide marginal accuracy which may not allow us distinguishing between extra natural inflation from natural inflation clearly unless the experimental accuracy canmore » be further improved.« less

Protection from annual flooding is correlated with increased cholera prevalence in Bangladesh: a zero-inflated regression analysis.

PubMed

Carrel, Margaret; Voss, Paul; Streatfield, Peter K; Yunus, Mohammad; Emch, Michael

2010-03-22

Alteration of natural or historical aquatic flows can have unintended consequences for regions where waterborne diseases are endemic and where the epidemiologic implications of such change are poorly understood. The implementation of flood protection measures for a portion of an intensely monitored population in Matlab, Bangladesh, allows us to examine whether cholera outcomes respond positively or negatively to measures designed to control river flooding. Using a zero inflated negative binomial model, we examine how selected covariates can simultaneously account for household clusters reporting no cholera from those with positive counts as well as distinguishing residential areas with low counts from areas with high cholera counts. Our goal is to examine how residence within or outside a flood protected area interacts with the probability of cholera presence and the effect of flood protection on the magnitude of cholera prevalence. In Matlab, living in a household that is protected from annual monsoon flooding appears to have no significant effect on whether the household experiences cholera, net of other covariates. However, counter-intuitively, among households where cholera is reported, living within the flood protected region significantly increases the number of cholera cases. The construction of dams or other water impoundment strategies for economic or social motives can have profound and unanticipated consequences for waterborne disease. Our results indicate that the construction of a flood control structure in rural Bangladesh is correlated with an increase in cholera cases for residents protected from annual monsoon flooding. Such a finding requires attention from both the health community and from governments and non-governmental organizations involved in ongoing water management schemes.

The Other Inflation

ERIC Educational Resources Information Center

Aristides

1976-01-01

The other inflation is grade inflation, the label affixed to the indisputable rise in the grade-point averages of undergraduates at public and private, elite and community colleges and universities across the country. The effects of grade inflation upon academic performance were assessed. (Author/RK)

Inflatable Vessel and Method

NASA Technical Reports Server (NTRS)

Raboin, Jasen L. (Inventor); Valle, Gerard D. (Inventor); Edeen, Gregg A. (Inventor); delaFuente, Horacio M. (Inventor); Schneider, William C. (Inventor); Spexarth, Gary R. (Inventor); Pandya, Shalini Gupta (Inventor); Johnson, Christopher J. (Inventor)

2003-01-01

An inflatable module comprising a structural core and an inflatable shell, wherein the inflatable shell is sealingly attached to the structural core. In its launch or pre-deployed configuration, the wall thickness of the inflatable shell is collapsed by vacuum. Also in this configuration, the inflatable shell is collapsed and efficiently folded around the structural core. Upon deployment, the wall thickness of the inflatable shell is inflated; whereby the inflatable shell itself, is thereby inflated around the structural core, defining therein a large enclosed volume. A plurality of removable shelves are arranged interior to the structural core in the launch configuration. The structural core also includes at least one longeron that, in conjunction with the shelves, primarily constitute the rigid, strong, and lightweight load-bearing structure of the module during launch. The removable shelves are detachable from their arrangement in the launch configuration so that, when the module is in its deployed configuration and launch loads no longer exist, the shelves can be rearranged to provide a module interior arrangement suitable for human habitation and work. In the preferred embodiment, to provide efficiency in structural load paths and attachments, the shape of the inflatable shell is a cylinder with semi-toroidal ends.

Compositions, Random Sums and Continued Random Fractions of Poisson and Fractional Poisson Processes

NASA Astrophysics Data System (ADS)

Orsingher, Enzo; Polito, Federico

2012-08-01

In this paper we consider the relation between random sums and compositions of different processes. In particular, for independent Poisson processes N α ( t), N β ( t), t>0, we have that N_{α}(N_{β}(t)) stackrel{d}{=} sum_{j=1}^{N_{β}(t)} Xj, where the X j s are Poisson random variables. We present a series of similar cases, where the outer process is Poisson with different inner processes. We highlight generalisations of these results where the external process is infinitely divisible. A section of the paper concerns compositions of the form N_{α}(tauk^{ν}), ν∈(0,1], where tauk^{ν} is the inverse of the fractional Poisson process, and we show how these compositions can be represented as random sums. Furthermore we study compositions of the form Θ( N( t)), t>0, which can be represented as random products. The last section is devoted to studying continued fractions of Cauchy random variables with a Poisson number of levels. We evaluate the exact distribution and derive the scale parameter in terms of ratios of Fibonacci numbers.

Inflation from Minkowski space

DOE PAGES

Pirtskhalava, David; Santoni, Luca; Trincherini, Enrico; ...

2014-12-23

Here, we propose a class of scalar models that, once coupled to gravity, lead to cosmologies that smoothly and stably connect an inflationary quasi-de Sitter universe to a low, or even zero-curvature, maximally symmetric spacetime in the asymptotic past, strongly violating the null energy condition (H • >>H2) at intermediate times. The models are deformations of the conformal galileon lagrangian and are therefore based on symmetries, both exact and approximate, that ensure the quantum robustness of the whole picture. The resulting cosmological backgrounds can be viewed as regularized extensions of the galilean genesis scenario, or, equivalently, as ‘early-time-complete’ realizations ofmore » inflation. The late-time inflationary dynamics possesses phenomenologically interesting properties: it can produce a large tensor-to-scalar ratio within the regime of validity of the effective field theory and can lead to sizeable equilateral nongaussianities.« less

Cumulative Poisson Distribution Program

NASA Technical Reports Server (NTRS)

Bowerman, Paul N.; Scheuer, Ernest M.; Nolty, Robert

1990-01-01

Overflow and underflow in sums prevented. Cumulative Poisson Distribution Program, CUMPOIS, one of two computer programs that make calculations involving cumulative Poisson distributions. Both programs, CUMPOIS (NPO-17714) and NEWTPOIS (NPO-17715), used independently of one another. CUMPOIS determines cumulative Poisson distribution, used to evaluate cumulative distribution function (cdf) for gamma distributions with integer shape parameters and cdf for X (sup2) distributions with even degrees of freedom. Used by statisticians and others concerned with probabilities of independent events occurring over specific units of time, area, or volume. Written in C.

Supernatural inflation: inflation from supersymmetry with no (very) small parameters

NASA Astrophysics Data System (ADS)

Randall, Lisa; SoljačiĆ, Marin; Guth, Alan H.

1996-02-01

Most models of inflation have small parameters, either to guarantee sufficient inflation or the correct magnitude of the density perturbations. In this paper we show that, in supersymmetric theories with weak-scale supersymmetry breaking, one can construct viable inflationary models in which the requisite parameters appear naturally in the form of the ratio of mass scales that are already present in the theory. Successful inflationary models can be constructed from the flat-direction fields of a renormalizable supersymmetric potential, and such models can be realized even in the context of a simple GUT extension of the MSSM. We evade naive ``naturalness'' arguments by allowing for more than one field to be relevant to inflation, as in ``hybrid inflation'' models, and we argue that this is the most natural possibility if inflation fields are to be associated with flat direction fields of a supersymmetric theory. Such models predict a very low Hubble constant during inflation, of order 103-104 GeV, a scalar density perturbation index n which is very close to or greater than unity, and negligible tensor perturbations. In addition, these models lead to a large spike in the density perturbation spectrum at short wavelengths.

Decryption-decompression of AES protected ZIP files on GPUs

NASA Astrophysics Data System (ADS)

Duong, Tan Nhat; Pham, Phong Hong; Nguyen, Duc Huu; Nguyen, Thuy Thanh; Le, Hung Duc

2011-10-01

AES is a strong encryption system, so decryption-decompression of AES encrypted ZIP files requires very large computing power and techniques of reducing the password space. This makes implementations of techniques on common computing system not practical. In [1], we reduced the original very large password search space to a much smaller one which surely containing the correct password. Based on reduced set of passwords, in this paper, we parallel decryption, decompression and plain text recognition for encrypted ZIP files by using CUDA computing technology on graphics cards GeForce GTX295 of NVIDIA, to find out the correct password. The experimental results have shown that the speed of decrypting, decompressing, recognizing plain text and finding out the original password increases about from 45 to 180 times (depends on the number of GPUs) compared to sequential execution on the Intel Core 2 Quad Q8400 2.66 GHz. These results have demonstrated the potential applicability of GPUs in this cryptanalysis field.

Nonlinear Poisson Equation for Heterogeneous Media

PubMed Central

Hu, Langhua; Wei, Guo-Wei

2012-01-01

The Poisson equation is a widely accepted model for electrostatic analysis. However, the Poisson equation is derived based on electric polarizations in a linear, isotropic, and homogeneous dielectric medium. This article introduces a nonlinear Poisson equation to take into consideration of hyperpolarization effects due to intensive charges and possible nonlinear, anisotropic, and heterogeneous media. Variational principle is utilized to derive the nonlinear Poisson model from an electrostatic energy functional. To apply the proposed nonlinear Poisson equation for the solvation analysis, we also construct a nonpolar solvation energy functional based on the nonlinear Poisson equation by using the geometric measure theory. At a fixed temperature, the proposed nonlinear Poisson theory is extensively validated by the electrostatic analysis of the Kirkwood model and a set of 20 proteins, and the solvation analysis of a set of 17 small molecules whose experimental measurements are also available for a comparison. Moreover, the nonlinear Poisson equation is further applied to the solvation analysis of 21 compounds at different temperatures. Numerical results are compared to theoretical prediction, experimental measurements, and those obtained from other theoretical methods in the literature. A good agreement between our results and experimental data as well as theoretical results suggests that the proposed nonlinear Poisson model is a potentially useful model for electrostatic analysis involving hyperpolarization effects. PMID:22947937

Nonlinear Poisson equation for heterogeneous media.

PubMed

Hu, Langhua; Wei, Guo-Wei

2012-08-22

The Poisson equation is a widely accepted model for electrostatic analysis. However, the Poisson equation is derived based on electric polarizations in a linear, isotropic, and homogeneous dielectric medium. This article introduces a nonlinear Poisson equation to take into consideration of hyperpolarization effects due to intensive charges and possible nonlinear, anisotropic, and heterogeneous media. Variational principle is utilized to derive the nonlinear Poisson model from an electrostatic energy functional. To apply the proposed nonlinear Poisson equation for the solvation analysis, we also construct a nonpolar solvation energy functional based on the nonlinear Poisson equation by using the geometric measure theory. At a fixed temperature, the proposed nonlinear Poisson theory is extensively validated by the electrostatic analysis of the Kirkwood model and a set of 20 proteins, and the solvation analysis of a set of 17 small molecules whose experimental measurements are also available for a comparison. Moreover, the nonlinear Poisson equation is further applied to the solvation analysis of 21 compounds at different temperatures. Numerical results are compared to theoretical prediction, experimental measurements, and those obtained from other theoretical methods in the literature. A good agreement between our results and experimental data as well as theoretical results suggests that the proposed nonlinear Poisson model is a potentially useful model for electrostatic analysis involving hyperpolarization effects. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Soft inflation. [in cosmology

NASA Technical Reports Server (NTRS)

Berkin, Andrew L.; Maeda, Kei-Ichi; Yokoyama, Jun'ichi

1990-01-01

The cosmology resulting from two coupled scalar fields was studied, one which is either a new inflation or chaotic type inflation, and the other which has an exponentially decaying potential. Such a potential may appear in the conformally transformed frame of generalized Einstein theories like the Jordan-Brans-Dicke theory. The constraints necessary for successful inflation are examined. Conventional GUT models such as SU(5) were found to be compatible with new inflation, while restrictions on the self-coupling constant are significantly loosened for chaotic inflation.

The emergence of gravity as a retro-causal post-inflation macro-quantum-coherent holographic vacuum Higgs-Goldstone field

NASA Astrophysics Data System (ADS)

Sarfatti, Jack; Levit, Creon

2009-06-01

We present a model for the origin of gravity, dark energy and dark matter: Dark energy and dark matter are residual pre-inflation false vacuum random zero point energy (w = - 1) of large-scale negative, and short-scale positive pressure, respectively, corresponding to the "zero point" (incoherent) component of a superfluid (supersolid) ground state. Gravity, in contrast, arises from the 2nd order topological defects in the post-inflation virtual "condensate" (coherent) component. We predict, as a consequence, that the LHC will never detect exotic real on-mass-shell particles that can explain dark matter ΩMDM approx 0.23. We also point out that the future holographic dark energy de Sitter horizon is a total absorber (in the sense of retro-causal Wheeler-Feynman action-at-a-distance electrodynamics) because it is an infinite redshift surface for static detectors. Therefore, the advanced Hawking-Unruh thermal radiation from the future de Sitter horizon is a candidate for the negative pressure dark vacuum energy.

Poisson's ratio of fiber-reinforced composites

NASA Astrophysics Data System (ADS)

Christiansson, Henrik; Helsing, Johan

1996-05-01

Poisson's ratio flow diagrams, that is, the Poisson's ratio versus the fiber fraction, are obtained numerically for hexagonal arrays of elastic circular fibers in an elastic matrix. High numerical accuracy is achieved through the use of an interface integral equation method. Questions concerning fixed point theorems and the validity of existing asymptotic relations are investigated and partially resolved. Our findings for the transverse effective Poisson's ratio, together with earlier results for random systems by other authors, make it possible to formulate a general statement for Poisson's ratio flow diagrams: For composites with circular fibers and where the phase Poisson's ratios are equal to 1/3, the system with the lowest stiffness ratio has the highest Poisson's ratio. For other choices of the elastic moduli for the phases, no simple statement can be made.

Characterization of a putative grapevine Zn transporter, VvZIP3, suggests its involvement in early reproductive development in Vitis vinifera L

PubMed Central

2012-01-01

Background Zinc (Zn) deficiency is one of the most widespread mineral nutritional problems that affect normal development in plants. Because Zn cannot passively diffuse across cell membranes, it must be transported into intracellular compartments for all biological processes where Zn is required. Several members of the Zinc-regulated transporters, Iron-regulated transporter-like Protein (ZIP) gene family have been characterized in plants, and have shown to be involved in metal uptake and transport. This study describes the first putative Zn transporter in grapevine. Unravelling its function may explain an important symptom of Zn deficiency in grapevines, which is the production of clusters with fewer and usually smaller berries than normal. Results We identified and characterized a putative Zn transporter from berries of Vitis vinifera L., named VvZIP3. Compared to other members of the ZIP family identified in the Vitis vinifera L. genome, VvZIP3 is mainly expressed in reproductive tissue - specifically in developing flowers - which correlates with the high Zn accumulation in these organs. Contrary to this, the low expression of VvZIP3 in parthenocarpic berries shows a relationship with the lower Zn accumulation in this tissue than in normal seeded berries where its expression is induced by Zn. The predicted protein sequence indicates strong similarity with several members of the ZIP family from Arabidopsis thaliana and other species. Moreover, VvZIP3 complemented the growth defect of a yeast Zn-uptake mutant, ZHY3, and is localized in the plasma membrane of plant cells, suggesting that VvZIP3 has the function of a Zn uptake transporter. Conclusions Our results suggest that VvZIP3 encodes a putative plasma membrane Zn transporter protein member of the ZIP gene family that might play a role in Zn uptake and distribution during the early reproductive development in Vitis vinifera L., indicating that the availability of this micronutrient may be relevant for

Characterization of a putative grapevine Zn transporter, VvZIP3, suggests its involvement in early reproductive development in Vitis vinifera L.

PubMed

Gainza-Cortés, Felipe; Pérez-Dïaz, Ricardo; Pérez-Castro, Ramón; Tapia, Jaime; Casaretto, José A; González, Sebastián; Peña-Cortés, Hugo; Ruiz-Lara, Simón; González, Enrique

2012-07-23

Zinc (Zn) deficiency is one of the most widespread mineral nutritional problems that affect normal development in plants. Because Zn cannot passively diffuse across cell membranes, it must be transported into intracellular compartments for all biological processes where Zn is required. Several members of the Zinc-regulated transporters, Iron-regulated transporter-like Protein (ZIP) gene family have been characterized in plants, and have shown to be involved in metal uptake and transport. This study describes the first putative Zn transporter in grapevine. Unravelling its function may explain an important symptom of Zn deficiency in grapevines, which is the production of clusters with fewer and usually smaller berries than normal. We identified and characterized a putative Zn transporter from berries of Vitis vinifera L., named VvZIP3. Compared to other members of the ZIP family identified in the Vitis vinifera L. genome, VvZIP3 is mainly expressed in reproductive tissue - specifically in developing flowers - which correlates with the high Zn accumulation in these organs. Contrary to this, the low expression of VvZIP3 in parthenocarpic berries shows a relationship with the lower Zn accumulation in this tissue than in normal seeded berries where its expression is induced by Zn. The predicted protein sequence indicates strong similarity with several members of the ZIP family from Arabidopsis thaliana and other species. Moreover, VvZIP3 complemented the growth defect of a yeast Zn-uptake mutant, ZHY3, and is localized in the plasma membrane of plant cells, suggesting that VvZIP3 has the function of a Zn uptake transporter. Our results suggest that VvZIP3 encodes a putative plasma membrane Zn transporter protein member of the ZIP gene family that might play a role in Zn uptake and distribution during the early reproductive development in Vitis vinifera L., indicating that the availability of this micronutrient may be relevant for reproductive development.

Role of Homeodomain leucine zipper (HD-Zip) IV transcription factors in plant development and plant protection from deleterious environmental factors.

PubMed

Chew, William; Hrmova, Maria; Lopato, Sergiy

2013-04-12

Homeobox genes comprise an important group of genes that are responsible for regulation of developmental processes. These genes determine cell differentiation and cell fate in all eukaryotic organisms, starting from the early stages of embryo development. Homeodomain leucine zipper (HD-Zip) transcription factors are unique to the plant kingdom. Members of the HD-Zip IV subfamily have a complex domain topology and can bind several cis-elements with overlapping sequences. Many of the reported HD-Zip IV genes were shown to be specifically or preferentially expressed in plant epidermal or sub-epidermal cells. HD-Zip IV TFs were found to be associated with differentiation and maintenance of outer cell layers, and regulation of lipid biosynthesis and transport. Insights about the role of these proteins in plant cuticle formation, and hence their possible involvement in plant protection from pathogens and abiotic stresses has just started to emerge. These roles make HD-Zip IV proteins an attractive tool for genetic engineering of crop plants. To this end, there is a need for in-depth studies to further clarify the function of each HD-Zip IV subfamily member in commercially important plant species.

Role of Homeodomain Leucine Zipper (HD-Zip) IV Transcription Factors in Plant Development and Plant Protection from Deleterious Environmental Factors

PubMed Central

Chew, William; Hrmova, Maria; Lopato, Sergiy

2013-01-01

Homeobox genes comprise an important group of genes that are responsible for regulation of developmental processes. These genes determine cell differentiation and cell fate in all eukaryotic organisms, starting from the early stages of embryo development. Homeodomain leucine zipper (HD-Zip) transcription factors are unique to the plant kingdom. Members of the HD-Zip IV subfamily have a complex domain topology and can bind several cis-elements with overlapping sequences. Many of the reported HD-Zip IV genes were shown to be specifically or preferentially expressed in plant epidermal or sub-epidermal cells. HD-Zip IV TFs were found to be associated with differentiation and maintenance of outer cell layers, and regulation of lipid biosynthesis and transport. Insights about the role of these proteins in plant cuticle formation, and hence their possible involvement in plant protection from pathogens and abiotic stresses has just started to emerge. These roles make HD-Zip IV proteins an attractive tool for genetic engineering of crop plants. To this end, there is a need for in-depth studies to further clarify the function of each HD-Zip IV subfamily member in commercially important plant species. PMID:23584027

Abscisic-acid-dependent basic leucine zipper (bZIP) transcription factors in plant abiotic stress.

PubMed

Banerjee, Aditya; Roychoudhury, Aryadeep

2017-01-01

One of the major causes of significant crop loss throughout the world is the myriad of environmental stresses including drought, salinity, cold, heavy metal toxicity, and ultraviolet-B (UV-B) rays. Plants as sessile organisms have evolved various effective mechanism which enable them to withstand this plethora of stresses. Most of such regulatory mechanisms usually follow the abscisic-acid (ABA)-dependent pathway. In this review, we have primarily focussed on the basic leucine zipper (bZIP) transcription factors (TFs) activated by the ABA-mediated signalosome. Upon perception of ABA by specialized receptors, the signal is transduced via various groups of Ser/Thr kinases, which phosphorylate the bZIP TFs. Following such post-translational modification of TFs, they are activated so that they bind to specific cis-acting sequences called abscisic-acid-responsive elements (ABREs) or GC-rich coupling elements (CE), thereby influencing the expression of their target downstream genes. Several in silico techniques have been adopted so far to predict the structural features, recognize the regulatory modification sites, undergo phylogenetic analyses, and facilitate genome-wide survey of TF under multiple stresses. Current investigations on the epigenetic regulation that controls greater accessibility of the inducible regions of DNA of the target gene to the bZIP TFs exclusively under stress situations, along with the evolved stress memory responses via genomic imprinting mechanism, have been highlighted. The potentiality of overexpression of bZIP TFs, either in a homologous or in a heterologous background, in generating transgenic plants tolerant to various abiotic stressors have also been addressed by various groups. The present review will provide a coherent documentation on the functional characterization and regulation of bZIP TFs under multiple environmental stresses, with the major goal of generating multiple-stress-tolerant plant cultivars in near future.

Properties of the Bivariate Delayed Poisson Process

DTIC Science & Technology

1974-07-01

and Lewis (1972) in their Berkeley Symposium paper and here their analysis of the bivariate Poisson processes (without Poisson noise) is carried... Poisson processes . They cannot, however, be independent Poisson processes because their events are associated in pairs by the displace- ment centres...process because its marginal processes for events of each type are themselves (univariate) Poisson processes . Cox and Lewis (1972) assumed a

Transcriptome-Wide Survey and Expression Profile Analysis of Putative Chrysanthemum HD-Zip I and II Genes

PubMed Central

Song, Aiping; Li, Peiling; Xin, Jingjing; Chen, Sumei; Zhao, Kunkun; Wu, Dan; Fan, Qingqing; Gao, Tianwei; Chen, Fadi; Guan, Zhiyong

2016-01-01

The homeodomain-leucine zipper (HD-Zip) transcription factor family is a key transcription factor family and unique to the plant kingdom. It consists of a homeodomain and a leucine zipper that serve in combination as a dimerization motif. The family can be classified into four subfamilies, and these subfamilies participate in the development of hormones and mediation of hormone action and are involved in plant responses to environmental conditions. However, limited information on this gene family is available for the important chrysanthemum ornamental species (Chrysanthemum morifolium). Here, we characterized 17 chrysanthemum HD-Zip genes based on transcriptome sequences. Phylogenetic analyses revealed that 17 CmHB genes were distributed in the HD-Zip subfamilies I and II and identified two pairs of putative orthologous proteins in Arabidopsis and chrysanthemum and four pairs of paralogous proteins in chrysanthemum. The software MEME was used to identify 7 putative motifs with E values less than 1e-3 in the chrysanthemum HD-Zip factors, and they can be clearly classified into two groups based on the composition of the motifs. A bioinformatics analysis predicted that 8 CmHB genes could be targeted by 10 miRNA families, and the expression of these 17 genes in response to phytohormone treatments and abiotic stresses was characterized. The results presented here will promote research on the various functions of the HD-Zip gene family members in plant hormones and stress responses. PMID:27196930

Genomic identification of bZIP family genes involved in drought and heat stresses in strawberry (Fragaria vesca)

USDA-ARS?s Scientific Manuscript database

Basic leucine zipper (bZIP) genes are known to play dominant roles in plant response to development signals, as well as abiotic or biotic stress stimuli. Fifty bZIP genes across the woodland strawberry (Fragaria vesca) genome were identified and analyzed. They can be divided into 10 clades according...

From Loss of Memory to Poisson.

ERIC Educational Resources Information Center

Johnson, Bruce R.

1983-01-01

A way of presenting the Poisson process and deriving the Poisson distribution for upper-division courses in probability or mathematical statistics is presented. The main feature of the approach lies in the formulation of Poisson postulates with immediate intuitive appeal. (MNS)

First-order inflation. [in cosmology

NASA Technical Reports Server (NTRS)

Kolb, Edward W.

1991-01-01

In the original proposal, inflation occurred in the process of a strongly first-order phase transition. This model was soon demonstrated to be fatally flawed. Subsequent models for inflation involved phase transitions that were second-order, or perhaps weakly first-order; some even involved no phase transition at all. Recently the possibility of inflation during a strongly first-order phase transition has been revived. In this paper, some models for first-order inflation are discussed, and unique signatures that result if inflation is realized in a first-order transition are emphasized. Some of the history of inflation is reviewed to demonstrate how first-order inflation differs from other models.

Genome-Wide Investigation and Expression Profiling of HD-Zip Transcription Factors in Foxtail Millet (Setaria italica L.).

PubMed

Chai, Wenbo; Si, Weina; Ji, Wei; Qin, Qianqian; Zhao, Manli; Jiang, Haiyang

2018-01-01

HD-Zip proteins represent the major transcription factors in higher plants, playing essential roles in plant development and stress responses. Foxtail millet is a crop to investigate the systems biology of millet and biofuel grasses and the HD-Zip gene family has not been studied in foxtail millet. For further investigation of the expression profile of the HD-Zip gene family in foxtail millet, a comprehensive genome-wide expression analysis was conducted in this study. We found 47 protein-encoding genes in foxtail millet using BLAST search tools; the putative proteins were classified into four subfamilies, namely, subfamilies I, II, III, and IV. Gene structure and motif analysis indicate that the genes in one subfamily were conserved. Promotor analysis showed that HD-Zip gene was involved in abiotic stress. Duplication analysis revealed that 8 (~17%) hdz genes were tandemly duplicated and 28 (58%) were segmentally duplicated; purifying duplication plays important roles in gene expansion. Microsynteny analysis revealed the maximum relationship in foxtail millet-sorghum and foxtail millet-rice. Expression profiling upon the abiotic stresses of drought and high salinity and the biotic stress of ABA revealed that some genes regulated responses to drought and salinity stresses via an ABA-dependent process, especially sihdz29 and sihdz45. Our study provides new insight into evolutionary and functional analyses of HD-Zip genes involved in environmental stress responses in foxtail millet.

How thermal inflation can save minimal hybrid inflation in supergravity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dimopoulos, Konstantinos; Owen, Charlotte

2016-10-12

Minimal hybrid inflation in supergravity has been ruled out by the 2015 Planck observations because the spectral index of the produced curvature perturbation falls outside observational bounds. To resurrect the model, a number of modifications have been put forward but many of them spoil the accidental cancellation that resolves the η-problem and require complicated Kähler constructions to counterbalance the lost cancellation. In contrast, in this paper the model is rendered viable by supplementing the scenario with a brief period of thermal inflation, which follows the reheating of primordial inflation. The scalar field responsible for thermal inflation requires a large non-zeromore » vacuum expectation value (VEV) and a flat potential. We investigate the VEV of such a flaton field and its subsequent effect on the inflationary observables. We find that, for large VEV, minimal hybrid inflation in supergravity produces a spectral index within the 1-σ Planck bound and a tensor-to-scalar ratio which may be observable in the near future. The mechanism is applicable to other inflationary models.« less

Inflatable wing

DOEpatents

Priddy, Tommy G.

1988-01-01

An inflatable wing is formed from a pair of tapered, conical inflatable tubes in bonded tangential contact with each other. The tubes are further connected together by means of top and bottom reinforcement boards having corresponding longitudinal edges lying in the same central diametral plane passing through the associated tube. The reinforcement boards are made of a stiff reinforcement material, such as Kevlar, collapsible in a direction parallel to the spanwise wing axis upon deflation of the tubes. The stiff reinforcement material cooperates with the inflated tubes to impart structural I-beam characteristics to the composite structure for transferring inflation pressure-induced tensile stress from the tubes to the reinforcement boards. A plurality of rigid hoops shaped to provide airfoil definition are spaced from each other along the spanwise axis and are connected to the top and bottom reinforcement boards. Tension lines are employed for stabilizing the hoops along the trailing and leading edges thereof.

Inflatable nested toroid structure

NASA Technical Reports Server (NTRS)

Johnson, Christopher J. (Inventor); Raboin, Jasen L. (Inventor); Spexarth, Gary R. (Inventor)

2011-01-01

An inflatable structure comprises at least two generally toroidal, inflatable modules. When in a deployed mode, the first, inner module has a major diameter less than that of a second, outer module and is positioned within the inner circumference of the outer module such that the first module is nested circumferentially alongside the second module. The inflatable structure, in a non-deployed, non-inflated mode, is of compact configuration and adapted to be transported to a site of deployment. When deployed, the inflatable structure is of substantially increased interior volume. In one embodiment, access between the interior of the first module and the second module is provided by at least one port or structural pass-through. In another embodiment, the inflatable structure includes at least one additional generally toroidal module external of and circumferentially surrounding the second module.

Attractors, universality, and inflation

NASA Astrophysics Data System (ADS)

Downes, Sean; Dutta, Bhaskar; Sinha, Kuver

2012-11-01

Studies of the initial conditions for inflation have conflicting predictions from exponential suppression to inevitability. At the level of phase space, this conflict arises from the competing intuitions of CPT invariance and thermodynamics. After reviewing this conflict, we enlarge the ensemble beyond phase space to include scalar potential data. We show how this leads to an important contribution from inflection point inflation, enhancing the likelihood of inflation to a power law, 1/Ne3. In the process, we emphasize the attractor dynamics of the gravity-scalar system and the existence of universality classes from inflection point inflation. Finally, we comment on the predictivity of inflation in light of these results.

Prediction of vehicle crashes by drivers' characteristics and past traffic violations in Korea using a zero-inflated negative binomial model.

PubMed

Kim, Dae-Hwan; Ramjan, Lucie M; Mak, Kwok-Kei

2016-01-01

Traffic safety is a significant public health challenge, and vehicle crashes account for the majority of injuries. This study aims to identify whether drivers' characteristics and past traffic violations may predict vehicle crashes in Korea. A total of 500,000 drivers were randomly selected from the 11.6 million driver records of the Ministry of Land, Transport and Maritime Affairs in Korea. Records of traffic crashes were obtained from the archives of the Korea Insurance Development Institute. After matching the past violation history for the period 2004-2005 with the number of crashes in year 2006, a total of 488,139 observations were used for the analysis. Zero-inflated negative binomial model was used to determine the incident risk ratio (IRR) of vehicle crashes by past violations of individual drivers. The included covariates were driver's age, gender, district of residence, vehicle choice, and driving experience. Drivers violating (1) a hit-and-run or drunk driving regulation at least once and (2) a signal, central line, or speed regulation more than once had a higher risk of a vehicle crash with respective IRRs of 1.06 and 1.15. Furthermore, female gender, a younger age, fewer years of driving experience, and middle-sized vehicles were all significantly associated with a higher likelihood of vehicle crashes. Drivers' demographic characteristics and past traffic violations could predict vehicle crashes in Korea. Greater resources should be assigned to the provision of traffic safety education programs for the high-risk driver groups.

Investigation of Super*Zip separation joint

NASA Technical Reports Server (NTRS)

Bement, Laurence J.; Schimmel, Morry L.

1988-01-01

An investigation to determine the most likely cause of two failures of five tests on 79 inch diameter Lockheed Super*Zip spacecraft separation joints being used for the development of a Shuttle/Centaur propulsion system. This joint utilizes an explosively expanded tube to fracture surrounding prenotched aluminum plates to achieve planar separation. A test method was developed and more than 300 tests firings were made to provide an understanding of severance mechanisms and the functional performance effects of system variables. An approach for defining functional margin was developed, and specific recommendations were made for improving existing and future systems.

ZIP2DL: An Elastic-Plastic, Large-Rotation Finite-Element Stress Analysis and Crack-Growth Simulation Program

NASA Technical Reports Server (NTRS)

Deng, Xiaomin; Newman, James C., Jr.

1997-01-01

ZIP2DL is a two-dimensional, elastic-plastic finte element program for stress analysis and crack growth simulations, developed for the NASA Langley Research Center. It has many of the salient features of the ZIP2D program. For example, ZIP2DL contains five material models (linearly elastic, elastic-perfectly plastic, power-law hardening, linear hardening, and multi-linear hardening models), and it can simulate mixed-mode crack growth for prescribed crack growth paths under plane stress, plane strain and mixed state of stress conditions. Further, as an extension of ZIP2D, it also includes a number of new capabilities. The large-deformation kinematics in ZIP2DL will allow it to handle elastic problems with large strains and large rotations, and elastic-plastic problems with small strains and large rotations. Loading conditions in terms of surface traction, concentrated load, and nodal displacement can be applied with a default linear time dependence or they can be programmed according to a user-defined time dependence through a user subroutine. The restart capability of ZIP2DL will make it possible to stop the execution of the program at any time, analyze the results and/or modify execution options and resume and continue the execution of the program. This report includes three sectons: a theoretical manual section, a user manual section, and an example manual secton. In the theoretical secton, the mathematics behind the various aspects of the program are concisely outlined. In the user manual section, a line-by-line explanation of the input data is given. In the example manual secton, three types of examples are presented to demonstrate the accuracy and illustrate the use of this program.

Generation of a Slc39a8 hypomorph mouse: Markedly decreased ZIP8 Zn{sup 2+}/(HCO{sub 3}{sup -}){sub 2} transporter expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Bin; He, Lei; Dong, Hongbin

2011-07-01

Highlights: {yields} The mouse Slc39a8 gene encodes the ZIP8 transporter. {yields} ZIP8 functions endogenously as a electroneutral Zn{sup 2+}/(HCO{sub 3}{sup -}){sub 2} symporter. {yields} A Slc39a8(neo/neo) hypomorph mouse, due to retention of the neo mini-gene, has been created. {yields} ZIP8 expression in utero is {approx}90% decreased in all tissues examined. {yields} This mouse model will be useful for studying developmental and in utero physiological functions of ZIP8. -- Abstract: Previously this laboratory has identified the mouse Slc39a8 gene encoding the ZIP8 transporter, important in cadmium uptake. ZIP8 functions endogenously as a electroneutral Zn{sup 2+}/(HCO{sub 3}{sup -}){sub 2} symporter, moving bothmore » ions into the cell. The overall physiological importance of ZIP8 remains unclear. Herein we describe generation of a mouse line carrying the Slc39a8(neo) allele, containing the Frt-flanked neomycin-resistance (neo) mini-cassette in intron 3 and loxP sites in introns 3 and 6. Cre recombinase functions correctly in Escherichia coli and in adeno-Cre-infected mouse fetal fibroblasts, but does not function in the intact mouse for reasons not clear. Slc39a8(neo) is a hypomorphic allele, because Slc39a8(neo/neo) homozygotes exhibit dramatically decreased ZIP8 expression in embryo, fetus, and visceral yolk sac - in comparison to their littermate wild-type controls. This ZIP8 hypomorph will be instrumental in studying developmental and in utero physiological functions of the ZIP8 transporter.« less

bZIP17 regulates the expression of genes related to seed storage and germination, reducing seed susceptibility to osmotic stress.

PubMed

Cifuentes-Esquivel, Nicolás; Celiz-Balboa, Jonathan; Henriquez-Valencia, Carlos; Mitina, Irina; Arraño-Salinas, Paulina; Moreno, Adrián A; Meneses, Claudio; Blanco-Herrera, Francisca; Orellana, Ariel

2018-04-25

Low temperatures, salinity, and drought cause significant crop losses. These conditions involve osmotic stress, triggering transcriptional remodeling, and consequently, the restitution of cellular homeostasis and growth recovery. Protein transcription factors regulate target genes, thereby mediating plant responses to stress. bZIP17 is a transcription factor involved in cellular responses to salinity and the unfolded protein response. Because salinity can also produce osmotic stress, the role of bZIP17 in response to osmotic stress was assessed. Mannitol treatments induced the transcript accumulation and protein processing of bZIP17. Transcriptomic analyses showed that several genes associated with seed storage and germination showed lower expression in bzip17 mutants than in wild-type plants. Interestingly, bZIP17 transcript was more abundant in seeds, and germination analyses revealed that wild-type plants germinated later than bzip17 mutants in the presence of mannitol, but no effects were observed when the seeds were exposed to ABA. Finally, the transcript levels of bZIP17 target genes that control seed storage and germination were assessed in seeds exposed to mannitol treatments, which showed lower expression levels in bzip17 mutants compared to the wild-type seeds. These results suggest that bZIP17 plays a role in osmotic stress, acting as a negative regulator of germination through the regulation of genes involved in seed storage and germination. © 2018 Wiley Periodicals, Inc.

Constructions and classifications of projective Poisson varieties

NASA Astrophysics Data System (ADS)

Pym, Brent

2018-03-01

This paper is intended both as an introduction to the algebraic geometry of holomorphic Poisson brackets, and as a survey of results on the classification of projective Poisson manifolds that have been obtained in the past 20 years. It is based on the lecture series delivered by the author at the Poisson 2016 Summer School in Geneva. The paper begins with a detailed treatment of Poisson surfaces, including adjunction, ruled surfaces and blowups, and leading to a statement of the full birational classification. We then describe several constructions of Poisson threefolds, outlining the classification in the regular case, and the case of rank-one Fano threefolds (such as projective space). Following a brief introduction to the notion of Poisson subspaces, we discuss Bondal's conjecture on the dimensions of degeneracy loci on Poisson Fano manifolds. We close with a discussion of log symplectic manifolds with simple normal crossings degeneracy divisor, including a new proof of the classification in the case of rank-one Fano manifolds.

Constructions and classifications of projective Poisson varieties.

PubMed

Pym, Brent

2018-01-01

This paper is intended both as an introduction to the algebraic geometry of holomorphic Poisson brackets, and as a survey of results on the classification of projective Poisson manifolds that have been obtained in the past 20 years. It is based on the lecture series delivered by the author at the Poisson 2016 Summer School in Geneva. The paper begins with a detailed treatment of Poisson surfaces, including adjunction, ruled surfaces and blowups, and leading to a statement of the full birational classification. We then describe several constructions of Poisson threefolds, outlining the classification in the regular case, and the case of rank-one Fano threefolds (such as projective space). Following a brief introduction to the notion of Poisson subspaces, we discuss Bondal's conjecture on the dimensions of degeneracy loci on Poisson Fano manifolds. We close with a discussion of log symplectic manifolds with simple normal crossings degeneracy divisor, including a new proof of the classification in the case of rank-one Fano manifolds.

Modulus D-term inflation

NASA Astrophysics Data System (ADS)

Kadota, Kenji; Kobayashi, Tatsuo; Saga, Ikumi; Sumita, Keigo

2018-04-01

We propose a new model of single-field D-term inflation in supergravity, where the inflation is driven by a single modulus field which transforms non-linearly under the U(1) gauge symmetry. One of the notable features of our modulus D-term inflation scenario is that the global U(1) remains unbroken in the vacuum and hence our model is not plagued by the cosmic string problem which can exclude most of the conventional D-term inflation models proposed so far due to the CMB observations.

Exploring the bZIP transcription factor regulatory network in Neurospora crassa

PubMed Central

Tian, Chaoguang; Li, Jingyi; Glass, N. Louise

2011-01-01

Transcription factors (TFs) are key nodes of regulatory networks in eukaryotic organisms, including filamentous fungi such as Neurospora crassa. The 178 predicted DNA-binding TFs in N. crassa are distributed primarily among six gene families, which represent an ancient expansion in filamentous ascomycete genomes; 98 TF genes show detectable expression levels during vegetative growth of N. crassa, including 35 that show a significant difference in expression level between hyphae at the periphery versus hyphae in the interior of a colony. Regulatory networks within a species genome include paralogous TFs and their respective target genes (TF regulon). To investigate TF network evolution in N. crassa, we focused on the basic leucine zipper (bZIP) TF family, which contains nine members. We performed baseline transcriptional profiling during vegetative growth of the wild-type and seven isogenic, viable bZIP deletion mutants. We further characterized the regulatory network of one member of the bZIP family, NCU03905. NCU03905 encodes an Ap1-like protein (NcAp-1), which is involved in resistance to multiple stress responses, including oxidative and heavy metal stress. Relocalization of NcAp-1 from the cytoplasm to the nucleus was associated with exposure to stress. A comparison of the NcAp-1 regulon with Ap1-like regulons in Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida albicans and Aspergillus fumigatus showed both conservation and divergence. These data indicate how N. crassa responds to stress and provide information on pathway evolution. PMID:21081763

Exploring the bZIP transcription factor regulatory network in Neurospora crassa.

PubMed

Tian, Chaoguang; Li, Jingyi; Glass, N Louise

2011-03-01

Transcription factors (TFs) are key nodes of regulatory networks in eukaryotic organisms, including filamentous fungi such as Neurospora crassa. The 178 predicted DNA-binding TFs in N. crassa are distributed primarily among six gene families, which represent an ancient expansion in filamentous ascomycete genomes; 98 TF genes show detectable expression levels during vegetative growth of N. crassa, including 35 that show a significant difference in expression level between hyphae at the periphery versus hyphae in the interior of a colony. Regulatory networks within a species genome include paralogous TFs and their respective target genes (TF regulon). To investigate TF network evolution in N. crassa, we focused on the basic leucine zipper (bZIP) TF family, which contains nine members. We performed baseline transcriptional profiling during vegetative growth of the wild-type and seven isogenic, viable bZIP deletion mutants. We further characterized the regulatory network of one member of the bZIP family, NCU03905. NCU03905 encodes an Ap1-like protein (NcAp-1), which is involved in resistance to multiple stress responses, including oxidative and heavy metal stress. Relocalization of NcAp-1 from the cytoplasm to the nucleus was associated with exposure to stress. A comparison of the NcAp-1 regulon with Ap1-like regulons in Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida albicans and Aspergillus fumigatus showed both conservation and divergence. These data indicate how N. crassa responds to stress and provide information on pathway evolution.

Evolution and expression analysis reveal the potential role of the HD-Zip gene family in regulation of embryo abortion in grapes (Vitis vinifera L.).

PubMed

Li, Zhiqian; Zhang, Chen; Guo, Yurui; Niu, Weili; Wang, Yuejin; Xu, Yan

2017-09-21

The HD-Zip family has a diversity of functions during plant development. In this study, we identify 33 HD-Zip transcription factors in grape and detect their expressions in ovules and somatic embryos, as well as in various vegetative organs. A genome-wide survey for HD-Zip transcription factors in Vitis was conducted based on the 12 X grape genome (V. vinifera L.). A total of 33 members were identified and classified into four subfamilies (I-IV) based on phylogeny analysis with Arabidopsis, rice and maize. VvHDZs in the same subfamily have similar protein motifs and intron/exon structures. An evaluation of duplication events suggests several HD-Zip genes arose before the divergence of the grape and Arabidopsis lineages. The 33 members of HD-Zip were differentially expressed in ovules of the stenospermic grape, Thompson Seedless and of the seeded grape, Pinot noir. Most have higher expressions during ovule abortion in Thompson Seedless. In addition, transcripts of the HD-Zip family were also detected in somatic embryogenesis of Thompson Seedless and in different vegetative organs of Thompson Seedless at varying levels. Additionally, VvHDZ28 is located in the nucleus and had transcriptional activity consistent with the typical features of the HD-Zip family. Our results provide a foundation for future grape HD-Zip gene function research. The identification and expression profiles of the HD-Zip transcription factors in grape, reveal their diverse roles during ovule abortion and organ development. Our results lay a foundation for functional analysis of grape HDZ genes.

The Populus Class III HD ZIP transcription factor POPCORONA affects cell differentiation during secondary growth of woody stems

Treesearch

Juan Du; Eriko Miura; Marcel Robischon; Ciera Martinez; Andrew Groover

2011-01-01

The developmental mechanisms regulating cell differentiation and patterning during the secondary growth of woody tissues are poorly understood. Class III HD ZIP transcription factors are evolutionarily ancient and play fundamental roles in various aspects of plant development. Here we investigate the role of a Class III HD ZIP transcription factor, ...

Kähler-driven tribrid inflation

NASA Astrophysics Data System (ADS)

Antusch, Stefan; Nolde, David

2012-11-01

We discuss a new class of tribrid inflation models in supergravity, where the shape of the inflaton potential is dominated by effects from the Kähler potential. Tribrid inflation is a variant of hybrid inflation which is particularly suited for connecting inflation with particle physics, since the inflaton can be a D-flat combination of charged fields from the matter sector. In models of tribrid inflation studied so far, the inflaton potential was dominated by either loop corrections or by mixing effects with the waterfall field (as in "pseudosmooth" tribrid inflation). Here we investigate the third possibility, namely that tribrid inflation is dominantly driven by effects from higher-dimensional operators of the Kähler potential. We specify for which superpotential parameters the new regime is realized and show how it can be experimentally distinguished from the other two (loop-driven and "pseudosmooth") regimes.

ZIP8 expression in human proximal tubule cells, human urothelial cells transformed by Cd+2 and As+3 and in specimens of normal human urothelium and urothelial cancer

PubMed Central

2012-01-01

Background ZIP8 functions endogenously as a Zn+2/HCO3- symporter that can also bring cadmium (Cd+2) into the cell. It has also been proposed that ZIP8 participates in Cd-induced testicular necrosis and renal disease. In this study real-time PCR, western analysis, immunostaining and fluorescent localization were used to define the expression of ZIP8 in human kidney, cultured human proximal tubule (HPT) cells, normal and malignant human urothelium and Cd+2 and arsenite (As+3) transformed urothelial cells. Results It was shown that in the renal system both the non-glycosylated and glycosylated form of ZIP8 was expressed in the proximal tubule cells with localization of ZIP8 to the cytoplasm and cell membrane; findings in line with previous studies on ZIP8. The studies in the bladder were the first to show that ZIP8 was expressed in normal urothelium and that ZIP8 could be localized to the paranuclear region. Studies in the UROtsa cell line confirmed a paranuclear localization of ZIP8, however addition of growth medium to the cells increased the expression of the protein in the UROtsa cells. In archival human samples of the normal urothelium, the expression of ZIP8 was variable in intensity whereas in urothelial cancers ZIP8 was expressed in 13 of 14 samples, with one high grade invasive urothelial cancer showing no expression. The expression of ZIP8 was similar in the Cd+2 and As+3 transformed UROtsa cell lines and their tumor transplants. Conclusion This is the first study which shows that ZIP8 is expressed in the normal urothelium and in bladder cancer. In addition the normal UROtsa cell line and its transformed counterparts show similar expression of ZIP8 compared to the normal urothelium and the urothelial cancers suggesting that the UROtsa cell line could serve as a model system to study the expression of ZIP8 in bladder disease. PMID:22550998

Nonlocal Poisson-Fermi model for ionic solvent.

PubMed

Xie, Dexuan; Liu, Jinn-Liang; Eisenberg, Bob

2016-07-01

We propose a nonlocal Poisson-Fermi model for ionic solvent that includes ion size effects and polarization correlations among water molecules in the calculation of electrostatic potential. It includes the previous Poisson-Fermi models as special cases, and its solution is the convolution of a solution of the corresponding nonlocal Poisson dielectric model with a Yukawa-like kernel function. The Fermi distribution is shown to be a set of optimal ionic concentration functions in the sense of minimizing an electrostatic potential free energy. Numerical results are reported to show the difference between a Poisson-Fermi solution and a corresponding Poisson solution.

Validity and reliability of the Fitbit Zip as a measure of preschool children’s step count

PubMed Central

Sharp, Catherine A; Mackintosh, Kelly A; Erjavec, Mihela; Pascoe, Duncan M; Horne, Pauline J

2017-01-01

Objectives Validation of physical activity measurement tools is essential to determine the relationship between physical activity and health in preschool children, but research to date has not focused on this priority. The aims of this study were to ascertain inter-rater reliability of observer step count, and interdevice reliability and validity of Fitbit Zip accelerometer step counts in preschool children. Methods Fifty-six children aged 3–4 years (29 girls) recruited from 10 nurseries in North Wales, UK, wore two Fitbit Zip accelerometers while performing a timed walking task in their childcare settings. Accelerometers were worn in secure pockets inside a custom-made tabard. Video recordings enabled two observers to independently code the number of steps performed in 3 min by each child during the walking task. Intraclass correlations (ICCs), concordance correlation coefficients, Bland-Altman plots and absolute per cent error were calculated to assess the reliability and validity of the consumer-grade device. Results An excellent ICC was found between the two observer codings (ICC=1.00) and the two Fitbit Zips (ICC=0.91). Concordance between the Fitbit Zips and observer counts was also high (r=0.77), with an acceptable absolute per cent error (6%–7%). Bland-Altman analyses identified a bias for Fitbit 1 of 22.8±19.1 steps with limits of agreement between −14.7 and 60.2 steps, and a bias for Fitbit 2 of 25.2±23.2 steps with limits of agreement between −20.2 and 70.5 steps. Conclusions Fitbit Zip accelerometers are a reliable and valid method of recording preschool children’s step count in a childcare setting. PMID:29081984

Expression Patterns and Correlations with Metabolic Markers of Zinc Transporters ZIP14 and ZNT1 in Obesity and Polycystic Ovary Syndrome

PubMed Central

Maxel, Trine; Svendsen, Pernille Fog; Smidt, Kamille; Lauridsen, Jesper Krogh; Brock, Birgitte; Pedersen, Steen Bønlykke; Rungby, Jørgen; Larsen, Agnete

2017-01-01

Polycystic ovary syndrome (PCOS) is associated with infertility, increased androgen levels, and insulin resistance. In adipose tissue, zinc facilitates insulin signaling. Circulating zinc levels are altered in obesity, diabetes, and PCOS; and zinc supplementation can ameliorate metabolic disturbances in PCOS. In adipose tissue, expression of zinc influx transporter ZIP14 varies with body mass index (BMI), clinical markers of metabolic syndrome, and peroxisome proliferator-activated receptor gamma (PPARG). In this study, we investigated expression levels of ZIP14 and PPARG in subcutaneous adipose tissue of 36 PCOS women (17 lean and 19 obese women) compared with 23 healthy controls (7 lean and 16 obese women). Further, expression levels of zinc transporter ZIP9, a recently identified androgen receptor, and zinc efflux transporter ZNT1 were investigated, alongside lipid profile and markers of glucose metabolism [insulin degrading enzyme, retinol-binding protein 4 (RBP4), and glucose transporter 4 (GLUT4)]. We find that ZIP14 expression is reduced in obesity and positively correlates with PPARG expression, which is downregulated with increasing BMI. ZNT1 is upregulated in obesity, and both ZIP14 and ZNT1 expression significantly correlates with clinical markers of altered glucose metabolism. In addition, RBP4 and GLUT4 associate with obesity, but an association with PCOS as such was present only for PPARG and RBP4. ZIP14 and ZNT1 does not relate to clinical androgen status and ZIP9 is unaffected by all parameters investigated. In conclusion, our findings support the existence of a zinc dyshomeostasis in adipose tissue in metabolic disturbances including PCOS-related obesity. PMID:28303117

The Populus class III HD ZIP, popREVOLUTA, influences cambium initiation and patterning of woody stems.

PubMed

Robischon, Marcel; Du, Juan; Miura, Eriko; Groover, Andrew

2011-03-01

The secondary growth of a woody stem requires the formation of a vascular cambium at an appropriate position and proper patterning of the vascular tissues derived from the cambium. Class III homeodomain-leucine zipper (HD ZIP) transcription factors have been implicated in polarity determination and patterning in lateral organs and primary vascular tissues and in the initiation and function of shoot apical meristems. We report here the functional characterization of a Populus class III HD ZIP gene, popREVOLUTA (PRE), that demonstrates another role for class III HD ZIPs in regulating the development of cambia and secondary vascular tissues. PRE is orthologous to Arabidopsis (Arabidopsis thaliana) REVOLUTA and is expressed in both the shoot apical meristem and in the cambial zone and secondary vascular tissues. Transgenic Populus expressing a microRNA-resistant form of PRE presents unstable phenotypic abnormalities affecting both primary and secondary growth. Surprisingly, phenotypic changes include abnormal formation of cambia within cortical parenchyma that can produce secondary vascular tissues in reverse polarity. Genes misexpressed in PRE mutants include transcription factors and auxin-related genes previously implicated in class III HD ZIP functions during primary growth. Together, these results suggest that PRE plays a fundamental role in the initiation of the cambium and in regulating the patterning of secondary vascular tissues.

No-scale inflation

NASA Astrophysics Data System (ADS)

Ellis, John; Garcia, Marcos A. G.; Nanopoulos, Dimitri V.; Olive, Keith A.

2016-05-01

Supersymmetry is the most natural framework for physics above the TeV scale, and the corresponding framework for early-Universe cosmology, including inflation, is supergravity. No-scale supergravity emerges from generic string compactifications and yields a non-negative potential, and is therefore a plausible framework for constructing models of inflation. No-scale inflation yields naturally predictions similar to those of the Starobinsky model based on R+{R}2 gravity, with a tilted spectrum of scalar perturbations: {n}s∼ 0.96, and small values of the tensor-to-scalar perturbation ratio r\\lt 0.1, as favoured by Planck and other data on the cosmic microwave background (CMB). Detailed measurements of the CMB may provide insights into the embedding of inflation within string theory as well as its links to collider physics.

Gravitational waves from warm inflation

NASA Astrophysics Data System (ADS)

Li, Xi-Bin; Wang, He; Zhu, Jian-Yang

2018-03-01

A fundamental prediction of inflation is a nearly scale-invariant spectrum of gravitational wave. The features of such a signal provide extremely important information about the physics of the early universe. In this paper, we focus on several topics about warm inflation. First, we discuss the stability property about warm inflation based on nonequilibrium statistical mechanics, which gives more fundamental physical illustrations to thermal property of such model. Then, we calculate the power spectrum of gravitational waves generated during warm inflation, in which there are three components contributing to such spectrum: thermal term, quantum term, and cross term combining the both. We also discuss some interesting properties about these terms and illustrate them in different panels. As a model different from cold inflation, warm inflation model has its individual properties in observational practice, so we finally give a discussion about the observational effect to distinguish it from cold inflation.

Requirement of Zinc Transporter SLC39A7/ZIP7 for Dermal Development to Fine-Tune Endoplasmic Reticulum Function by Regulating Protein Disulfide Isomerase.

PubMed

Bin, Bum-Ho; Bhin, Jinhyuk; Seo, Juyeon; Kim, Se-Young; Lee, Eunyoung; Park, Kyuhee; Choi, Dong-Hwa; Takagishi, Teruhisa; Hara, Takafumi; Hwang, Daehee; Koseki, Haruhiko; Asada, Yoshinobu; Shimoda, Shinji; Mishima, Kenji; Fukada, Toshiyuki

2017-08-01

Skin is the first area that manifests zinc deficiency. However, the molecular mechanisms by which zinc homeostasis affects skin development remain largely unknown. Here, we show that zinc-regulation transporter-/iron-regulation transporter-like protein 7 (ZIP7) localized to the endoplasmic reticulum plays critical roles in connective tissue development. Mice lacking the Slc39a7/Zip7 gene in collagen 1-expressing tissue exhibited dermal dysplasia. Ablation of ZIP7 in mesenchymal stem cells inhibited cell proliferation thereby preventing proper dermis formation, indicating that ZIP7 is required for dermal development. We also found that mesenchymal stem cells lacking ZIP7 accumulated zinc in the endoplasmic reticulum, which triggered zinc-dependent aggregation and inhibition of protein disulfide isomerase, leading to endoplasmic reticulum dysfunction. These results suggest that ZIP7 is necessary for endoplasmic reticulum function in mesenchymal stem cells and, as such, is essential for dermal development. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

STS-45 crewmembers during zero gravity activities onboard KC-135 NASA 930

NASA Image and Video Library

1991-08-21

S91-44453 (21 Aug 1991) --- The crew of STS-45 is already training for its March 1992 mission, including stints on the KC-135 zero-gravity-simulating aircraft. Shown with an inflatable globe are, clockwise from the top, C. Michael Foale, mission specialist; Dirk Frimout, payload specialist; Brian Duffy, pilot; Charles R. (Rick) Chappell, backup payload specialist; Charles F. Bolden, mission commander; Byron K. Lichtenberg, payload specialist; and Kathryn D. Sullivan, payload commander.

Current hormonal contraceptive use predicts female extra-pair and dyadic sexual behavior: evidence based on Czech National Survey data.

PubMed

Klapilová, Kateřina; Cobey, Kelly D; Wells, Timothy; Roberts, S Craig; Weiss, Petr; Havlíček, Jan

2014-01-10

Data from 1155 Czech women (493 using oral contraception, 662 non-users), obtained from the Czech National Survey of Sexual Behavior, were used to investigate evolutionary-based hypotheses concerning the predictive value of current oral contraceptive (OC) use on extra-pair and dyadic (in-pair) sexual behavior of coupled women. Specifically, the aim was to determine whether current OC use was associated with lower extra-pair and higher in-pair sexual interest and behavior, because OC use suppresses cyclical shifts in mating psychology that occur in normally cycling women. Zero-inflated Poisson (ZIP) regression and negative binomial models were used to test associations between OC use and these sexual measures, controlling for other relevant predictors (e.g., age, parity, in-pair sexual satisfaction, relationship length). The overall incidence of having had an extra-pair partner or one-night stand in the previous year was not related to current OC use (the majority of the sample had not). However, among the women who had engaged in extra-pair sexual behavior, OC users had fewer one-night stands than non-users, and tended to have fewer partners, than non-users. OC users also had more frequent dyadic intercourse than non-users, potentially indicating higher commitment to their current relationship. These results suggest that suppression of fertility through OC use may alter important aspects of female sexual behavior, with potential implications for relationship functioning and stability.

Selecting exposure measures in crash rate prediction for two-lane highway segments.

PubMed

Qin, Xiao; Ivan, John N; Ravishanker, Nalini

2004-03-01

A critical part of any risk assessment is identifying how to represent exposure to the risk involved. Recent research shows that the relationship between crash count and traffic volume is non-linear; consequently, a simple crash rate computed as the ratio of crash count to volume is not proper for comparing the safety of sites with different traffic volumes. To solve this problem, we describe a new approach for relating traffic volume and crash incidence. Specifically, we disaggregate crashes into four types: (1) single-vehicle, (2) multi-vehicle same direction, (3) multi-vehicle opposite direction, and (4) multi-vehicle intersecting, and define candidate exposure measures for each that we hypothesize will be linear with respect to each crash type. This paper describes initial investigation using crash and physical characteristics data for highway segments in Michigan from the Highway Safety Information System (HSIS). We use zero-inflated-Poisson (ZIP) modeling to estimate models for predicting counts for each of the above crash types as a function of the daily volume, segment length, speed limit and roadway width. We found that the relationship between crashes and the daily volume (AADT) is non-linear and varies by crash type, and is significantly different from the relationship between crashes and segment length for all crash types. Our research will provide information to improve accuracy of crash predictions and, thus, facilitate more meaningful comparison of the safety record of seemingly similar highway locations.

Parallel Demand-Withdraw Processes in Family Therapy for Adolescent Drug Abuse

PubMed Central

Rynes, Kristina N.; Rohrbaugh, Michael J.; Lebensohn-Chialvo, Florencia; Shoham, Varda

2013-01-01

Isomorphism, or parallel process, occurs in family therapy when patterns of therapist-client interaction replicate problematic interaction patterns within the family. This study investigated parallel demand-withdraw processes in Brief Strategic Family Therapy (BSFT) for adolescent drug abuse, hypothesizing that therapist-demand/adolescent-withdraw interaction (TD/AW) cycles observed early in treatment would predict poor adolescent outcomes at follow-up for families who exhibited entrenched parent-demand/adolescent-withdraw interaction (PD/AW) before treatment began. Participants were 91 families who received at least 4 sessions of BSFT in a multi-site clinical trial on adolescent drug abuse (Robbins et al., 2011). Prior to receiving therapy, families completed videotaped family interaction tasks from which trained observers coded PD/AW. Another team of raters coded TD/AW during two early BSFT sessions. The main dependent variable was the number of drug use days that adolescents reported in Timeline Follow-Back interviews 7 to 12 months after family therapy began. Zero-inflated Poisson (ZIP) regression analyses supported the main hypothesis, showing that PD/AW and TD/AW interacted to predict adolescent drug use at follow-up. For adolescents in high PD/AW families, higher levels of TD/AW predicted significant increases in drug use at follow-up, whereas for low PD/AW families, TD/AW and follow-up drug use were unrelated. Results suggest that attending to parallel demand-withdraw processes in parent/adolescent and therapist/adolescent dyads may be useful in family therapy for substance-using adolescents. PMID:23438248

Quasi-neutral limit of Euler–Poisson system of compressible fluids coupled to a magnetic field

NASA Astrophysics Data System (ADS)

Yang, Jianwei

2018-06-01

In this paper, we consider the quasi-neutral limit of a three-dimensional Euler-Poisson system of compressible fluids coupled to a magnetic field. We prove that, as Debye length tends to zero, periodic initial-value problems of the model have unique smooth solutions existing in the time interval where the ideal incompressible magnetohydrodynamic equations has smooth solution. Meanwhile, it is proved that smooth solutions converge to solutions of incompressible magnetohydrodynamic equations with a sharp convergence rate in the process of quasi-neutral limit.

Isolation and expression analysis of four HD-ZIP III family genes targeted by microRNA166 in peach.

PubMed

Zhang, C H; Zhang, B B; Ma, R J; Yu, M L; Guo, S L; Guo, L

2015-10-30

MicroRNA166 (miR166) is known to have highly conserved targets that encode proteins of the class III homeodomain-leucine zipper (HD-ZIP III) family, in a broad range of plant species. To further understand the relationship between HD-ZIP III genes and miR166, four HD-ZIP III family genes (PpHB14, PpHB15, PpHB8, and PpREV) were isolated from peach (Prunus persica) tissue and characterized. Spatio-temporal expression profiles of the genes were analyzed. Genes of the peach HD-ZIP III family were predicted to encode five conserved domains. Deduced amino acid sequences and tertiary structures of the four peach HD-ZIP III genes were highly conserved, with corresponding genes in Arabidopsis thaliana. The expression level of four targets displayed the opposite trend to that of miR166 throughout fruit development, with the exception of PpHB14 from 35 to 55 days after full bloom (DAFB). This finding indicates that miR166 may negatively regulate its four targets throughout fruit development. As for leaf and phloem, the same trend in expression level was observed between four targets and miR166 from 75 to 105 DAFB. However, the opposite trend was observed for the transcript level between four targets and miR166 from 35 to 55 DAFB. miRNA166 may negatively regulate four targets in some but not all developmental stages for a given tissue. The four genes studied were observed to have, exactly or generally, the same change tendency as individual tissue development, a finding that suggests genes of the HD-ZIP III family in peach may have complementary or cooperative functions in various tissues.

A genome-wide survey of homeodomain-leucine zipper genes and analysis of cold-responsive HD-Zip I members' expression in tomato.

PubMed

Zhang, Zhenzhu; Chen, Xiuling; Guan, Xin; Liu, Yang; Chen, Hongyu; Wang, Tingting; Mouekouba, Liana Dalcantara Ongouya; Li, Jingfu; Wang, Aoxue

2014-01-01

Homeodomain-leucine zipper (HD-Zip) proteins are a kind of transcriptional factors that play a vital role in plant growth and development. However, no detailed information of HD-Zip family in tomato has been reported till now. In this study, 51 HD-Zip genes (SlHZ01-51) in this family were identified and categorized into 4 classes by exon-intron and protein structure in tomato (Solanum lycopersicum) genome. The synthetical phylogenetic tree of tomato, Arabidopsis and rice HD-Zip genes were established for an insight into their evolutionary relationships and putative functions. The results showed that the contribution of segmental duplication was larger than that of tandem duplication for expansion and evolution of genes in this family of tomato. The expression profile results under abiotic stress suggested that all SlHZ I genes were responsive to cold stress. This study will provide a clue for the further investigation of functional identification and the role of tomato HD-Zip I subfamily in plant cold stress responses and developmental events.

Manifestations of poverty and birthrates among young teenagers in California zip code areas.

PubMed

Kirby, D; Coyle, K; Gould, J B

2001-01-01

Given that many communities are implementing community-wide initiatives to reduce teenage pregnancy or childbearing, it is important to understand the effects of a community's characteristics on adolescent birthrates. Data from the 1990 census and from California birth certificates were obtained for zip codes in California. Regression analyses were conducted on data from zip code areas with at least 200 females aged 15-17 between 1991 and 1996, to predict the effects of race and ethnicity marital status, education, employment, income and poverty, and housing on birthrates among young teenagers. In bivariate analyses, the proportion of families living below poverty level within a zip code was highly related to the birthrate among young teenagers in that zip code (r=.80, p<.001). In multivariate analyses, which controlled for some of the correlates of family poverty level, the proportion of families living below poverty level remained by far the most important predictor of the birthrate among young teenagers (b=1.54), followed by the proportion of adults aged 25 or older who have a college education (b=-0.80). Race and ethnicity were only weakly related to birthrate. In all three racial and ethnic groups, poverty and education were significantly related to birthrate, but the effect of college education was greater among Hispanics (b=-2.98) than among either non-Hispanic whites (b=-0.53) or blacks (b=-1.12). Male employment and unemployment and female unemployment were highly related to the birthrate among young teenagers in some racial or ethnic groups, but not in others. Multiple manifestations of poverty, including poverty itself, low levels of education and employment, and high levels of unemployment, may have a large impact upon birthrates among young teenagers. Addressing some of these issues could substantially reduce childbearing among young adolescents.

DNA Methylation Influences Chlorogenic Acid Biosynthesis in Lonicera japonica by Mediating LjbZIP8 to Regulate Phenylalanine Ammonia-Lyase 2 Expression.

PubMed

Zha, Liangping; Liu, Shuang; Liu, Juan; Jiang, Chao; Yu, Shulin; Yuan, Yuan; Yang, Jian; Wang, Yaolong; Huang, Luqi

2017-01-01

The content of active compounds differ in buds and flowers of Lonicera japonica (FLJ) and L. japonica var. chinensis (rFLJ). Chlorogenic acid (CGAs) were major active compounds of L. japonica and regarded as measurements for quality evaluation. However, little is known concerning the formation of active compounds at the molecular level. We quantified the major CGAs in FLJ and rFLJ, and found the concentrations of CGAs were higher in the buds of rFLJ than those of FLJ. Further analysis of CpG methylation of CGAs biosynthesis genes showed differences between FLJ and rFLJ in the 5'-UTR of phenylalanine ammonia-lyase 2 ( PAL2 ). We identified 11 LjbZIP proteins and 24 rLjbZIP proteins with conserved basic leucine zipper domains, subcellular localization, and electrophoretic mobility shift assay showed that the transcription factor LjbZIP8 is a nuclear-localized protein that specifically binds to the G-box element of the LjPAL2 5'-UTR. Additionally, a transactivation assay and LjbZIP8 overexpression in transgenic tobacco indicated that LjbZIP8 could function as a repressor of transcription. Finally, treatment with 5-azacytidine decreased the transcription level of LjPAL2 and CGAs content in FLJ leaves. These results raise the possibility that DNA methylation might influence the recruitment of LjbZIP8, regulating PAL2 expression level and CGAs content in L. japonica .

Can a supersonically expanding Bose-Einstein Condensates be used to study cosmological inflation?

NASA Astrophysics Data System (ADS)

Banik, Swarnav; Eckel, Stephen; Kumar, Avinash; Jacobson, Ted; Spielman, Ian; Campbell, Gretchen

2017-04-01

The massive scale of the universe makes the experimental study of cosmological inflation difficult. This has led to an interest in developing analogous systems using table top experiments. Here, we present the basic features of an expanding universe by drawing parallels with an expanding toroidal Bose Einstein Condensate (BEC) of 23Na atoms. The toroidal BEC serves as the background vacuum and phonons are the analogue to photons in the expanding universe. We study the dynamics of phonons in both non-expanding and expanding condensates and measure dissipation using the structure factor. We demonstrate red shifting of phonons and quasi-particle production similar to pre-heating after the inflation of universe. At the end of expansion, we also observe spontaneous non-zero winding numbers in the ring. Using Monte-Carlo simulations, we predict the widths of the resulting winding number distribution, which agree well with our experimental findings.

Alchemical inflation: inflaton turns into Higgs

NASA Astrophysics Data System (ADS)

Nakayama, Kazunori; Takahashi, Fuminobu

2012-11-01

We propose a new inflation model in which a gauge singlet inflaton turns into the Higgs condensate after inflation. The inflationary path is characterized by a moduli space of supersymmetric vacua spanned by the inflaton and Higgs field. The inflation energy scale is related to the soft supersymmetry breaking, and the Hubble parameter during inflation is smaller than the gravitino mass. The initial condition for the successful inflation is naturally realized by the pre-inflation in which the Higgs plays a role of the waterfall field.

Sharp predictions from eternal inflation patches in D-brane inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hertog, Thomas; Janssen, Oliver, E-mail: thomas.hertog@fys.kuleuven.be, E-mail: opj202@nyu.edu

We numerically generate the six-dimensional landscape of D3-brane inflation and identify patches of eternal inflation near sufficiently flat inflection points of the potential. We show that reasonable measures that select patches of eternal inflation in the landscape yield sharp predictions for the spectral properties of primordial perturbations on observable scales. These include a scalar tilt of .936, a running of the scalar tilt −.00103, undetectably small tensors and non-Gaussianity, and no observable spatial curvature. Our results explicitly demonstrate that precision cosmology probes the combination of the statistical properties of the string landscape and the measure implied by the universe's quantummore » state.« less

PpHB22, a member of HD-Zip proteins, activates PpDAM1 to regulate bud dormancy transition in 'Suli' pear (Pyrus pyrifolia White Pear Group).

PubMed

Yang, Qinsong; Niu, Qingfeng; Li, Jianzhao; Zheng, Xiaoyan; Ma, Yunjing; Bai, Songling; Teng, Yuanwen

2018-06-01

Homeodomain-leucine zipper (HD-Zip) proteins, which form one of the largest and most diverse families, regulate many biological processes in plants, including differentiation, flowering, vascular development, and stress signaling. Abscisic acid (ABA) has been proved to be one of the key regulators of bud dormancy and to influence several HD-Zip genes expression. However, the role of HD-Zip genes in regulating bud dormancy remains unclear. We identified 47 pear (P. pyrifolia White Pear Group) HD-Zip genes, which were classified into four subfamilies (HD-Zip I-IV). We further revealed that gene expression levels of some HD-Zip members were closely related to ABA concentrations in flower buds during dormancy transition. Exogenous ABA treatment confirmed that PpHB22 and several other HD-Zip genes responded to ABA. Yeast one-hybrid and dual luciferase assay results combining subcellular localization showed that PpHB22 was present in nucleus and directly induced PpDAM1 (dormancy associated MADS-box 1) expression. Thus, PpHB22 is a negative regulator of plant growth associated with the ABA response pathway and functions upstream of PpDAM1. These findings enrich our understanding of the function of HD-Zip genes related to the bud dormancy transition. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Modeling zero-modified count and semicontinuous data in health services research part 2: case studies.

PubMed

Neelon, Brian; O'Malley, A James; Smith, Valerie A

2016-11-30

This article is the second installment of a two-part tutorial on the analysis of zero-modified count and semicontinuous data. Part 1, which appears as a companion piece in this issue of Statistics in Medicine, provides a general background and overview of the topic, with particular emphasis on applications to health services research. Here, we present three case studies highlighting various approaches for the analysis of zero-modified data. The first case study describes methods for analyzing zero-inflated longitudinal count data. Case study 2 considers the use of hurdle models for the analysis of spatiotemporal count data. The third case study discusses an application of marginalized two-part models to the analysis of semicontinuous health expenditure data. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

On the fractal characterization of Paretian Poisson processes

NASA Astrophysics Data System (ADS)

Eliazar, Iddo I.; Sokolov, Igor M.

2012-06-01

Paretian Poisson processes are Poisson processes which are defined on the positive half-line, have maximal points, and are quantified by power-law intensities. Paretian Poisson processes are elemental in statistical physics, and are the bedrock of a host of power-law statistics ranging from Pareto's law to anomalous diffusion. In this paper we establish evenness-based fractal characterizations of Paretian Poisson processes. Considering an array of socioeconomic evenness-based measures of statistical heterogeneity, we show that: amongst the realm of Poisson processes which are defined on the positive half-line, and have maximal points, Paretian Poisson processes are the unique class of 'fractal processes' exhibiting scale-invariance. The results established in this paper are diametric to previous results asserting that the scale-invariance of Poisson processes-with respect to physical randomness-based measures of statistical heterogeneity-is characterized by exponential Poissonian intensities.

Topological inflation with graceful exit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marunović, Anja; Prokopec, Tomislav, E-mail: a.marunovic@uu.nl, E-mail: t.prokopec@uu.nl

We investigate a class of models of topological inflation in which a super-Hubble-sized global monopole seeds inflation. These models are attractive since inflation starts from rather generic initial conditions, but their not so attractive feature is that, unless symmetry is again restored, inflation never ends. In this work we show that, in presence of another nonminimally coupled scalar field, that is both quadratically and quartically coupled to the Ricci scalar, inflation naturally ends, representing an elegant solution to the graceful exit problem of topological inflation. While the monopole core grows during inflation, the growth stops after inflation, such that themore » monopole eventually enters the Hubble radius, and shrinks to its Minkowski space size, rendering it immaterial for the subsequent Universe's dynamics. Furthermore, we find that our model can produce cosmological perturbations that source CMB temperature fluctuations and seed large scale structure statistically consistent (within one standard deviation) with all available data. In particular, for small and (in our convention) negative nonminimal couplings, the scalar spectral index can be as large as n {sub s} ≅ 0.955, which is about one standard deviation lower than the central value quoted by the most recent Planck Collaboration.« less

Phenomenology of fermion production during axion inflation

NASA Astrophysics Data System (ADS)

Adshead, Peter; Pearce, Lauren; Peloso, Marco; Roberts, Michael A.; Sorbo, Lorenzo

2018-06-01

We study the production of fermions through a derivative coupling with a pseudoscalar inflaton and the effects of the produced fermions on the scalar primordial perturbations. We present analytic results for the modification of the scalar power spectrum due to the produced fermions, and we estimate the amplitude of the non-Gaussianities in the equilateral regime. Remarkably, we find a regime where the effect of the fermions gives the dominant contribution to the scalar spectrum while the amplitude of the bispectrum is small and in agreement with observation. We also note the existence of a regime in which the backreaction of the fermions on the evolution of the zero-mode of the inflaton can lead to inflation even if the potential of the inflaton is steep and does not satisfy the slow-roll conditions.

Observing the inflation potential. [in models of cosmological inflation

NASA Technical Reports Server (NTRS)

Copeland, Edmund J.; Kolb, Edward W.; Liddle, Andrew R.; Lidsey, James E.

1993-01-01

We show how observations of the density perturbation (scalar) spectrum and the gravitational wave (tensor) spectrum allow a reconstruction of the potential responsible for cosmological inflation. A complete functional reconstruction or a perturbative approximation about a single scale are possible; the suitability of each approach depends on the data available. Consistency equations between the scalar and tensor spectra are derived, which provide a powerful signal of inflation.

NEWTPOIS- NEWTON POISSON DISTRIBUTION PROGRAM

NASA Technical Reports Server (NTRS)

Bowerman, P. N.

1994-01-01

The cumulative poisson distribution program, NEWTPOIS, is one of two programs which make calculations involving cumulative poisson distributions. Both programs, NEWTPOIS (NPO-17715) and CUMPOIS (NPO-17714), can be used independently of one another. NEWTPOIS determines percentiles for gamma distributions with integer shape parameters and calculates percentiles for chi-square distributions with even degrees of freedom. It can be used by statisticians and others concerned with probabilities of independent events occurring over specific units of time, area, or volume. NEWTPOIS determines the Poisson parameter (lambda), that is; the mean (or expected) number of events occurring in a given unit of time, area, or space. Given that the user already knows the cumulative probability for a specific number of occurrences (n) it is usually a simple matter of substitution into the Poisson distribution summation to arrive at lambda. However, direct calculation of the Poisson parameter becomes difficult for small positive values of n and unmanageable for large values. NEWTPOIS uses Newton's iteration method to extract lambda from the initial value condition of the Poisson distribution where n=0, taking successive estimations until some user specified error term (epsilon) is reached. The NEWTPOIS program is written in C. It was developed on an IBM AT with a numeric co-processor using Microsoft C 5.0. Because the source code is written using standard C structures and functions, it should compile correctly on most C compilers. The program format is interactive, accepting epsilon, n, and the cumulative probability of the occurrence of n as inputs. It has been implemented under DOS 3.2 and has a memory requirement of 30K. NEWTPOIS was developed in 1988.

Properties of Zip4 accumulation during zinc deficiency and its usefulness to evaluate zinc status: a study of the effects of zinc deficiency during lactation.

PubMed

Hashimoto, Ayako; Nakagawa, Miki; Tsujimura, Natsuki; Miyazaki, Shiho; Kizu, Kumiko; Goto, Tomoko; Komatsu, Yusuke; Matsunaga, Ayu; Shirakawa, Hitoshi; Narita, Hiroshi; Kambe, Taiho; Komai, Michio

2016-03-01

Systemic and cellular zinc homeostasis is elaborately controlled by ZIP and ZnT zinc transporters. Therefore, detailed characterization of their expression properties is of importance. Of these transporter proteins, Zip4 functions as the primarily important transporter to control systemic zinc homeostasis because of its indispensable function of zinc absorption in the small intestine. In this study, we closely investigated Zip4 protein accumulation in the rat small intestine in response to zinc status using an anti-Zip4 monoclonal antibody that we generated and contrasted this with the zinc-responsive activity of the membrane-bound alkaline phosphatase (ALP). We found that Zip4 accumulation is more rapid in response to zinc deficiency than previously thought. Accumulation increased in the jejunum as early as 1 day following a zinc-deficient diet. In the small intestine, Zip4 protein expression was higher in the jejunum than in the duodenum and was accompanied by reduction of ALP activity, suggesting that the jejunum can become zinc deficient more easily. Furthermore, by monitoring Zip4 accumulation levels and ALP activity in the duodenum and jejunum, we reasserted that zinc deficiency during lactation may transiently alter plasma glucose levels in the offspring in a sex-specific manner, without affecting homeostatic control of zinc metabolism. This confirms that zinc nutrition during lactation is extremely important for the health of the offspring. These results reveal that rapid Zip4 accumulation provides a significant conceptual advance in understanding the molecular basis of systemic zinc homeostatic control, and that properties of Zip4 protein accumulation are useful to evaluate zinc status closely. Copyright © 2016 the American Physiological Society.

Pepper CabZIP63 acts as a positive regulator during Ralstonia solanacearum or high temperature-high humidity challenge in a positive feedback loop with CaWRKY40.

PubMed

Shen, Lei; Liu, Zhiqin; Yang, Sheng; Yang, Tong; Liang, Jiaqi; Wen, Jiayu; Liu, Yanyan; Li, Jiazhi; Shi, Lanping; Tang, Qian; Shi, Wei; Hu, Jiong; Liu, Cailing; Zhang, Yangwen; Lin, Wei; Wang, Rongzhang; Yu, Huanxin; Mou, Shaoliang; Hussain, Ansar; Cheng, Wei; Cai, Hanyang; He, Li; Guan, Deyi; Wu, Yang; He, Shuilin

2016-04-01

CaWRKY40 is known to act as a positive regulator in the response of pepper (Capsicum annuum) to Ralstonia solanacearum inoculation (RSI) or high temperature-high humidity (HTHH), but the underlying mechanism remains elusive. Herein, we report that CabZIP63, a pepper bZIP family member, participates in this process by regulating the expression of CaWRKY40. CabZIP63 was found to localize in the nuclei, be up-regulated by RSI or HTHH, bind to promoters of both CabZIP63(pCabZIP63) and CaWRKY40(pCaWRKY40), and activate pCabZIP63- and pCaWRKY40-driven β-glucuronidase expression in a C- or G-box-dependent manner. Silencing of CabZIP63 by virus-induced gene silencing (VIGS) in pepper plants significantly attenuated their resistance to RSI and tolerance to HTHH, accompanied by down-regulation of immunity- or thermotolerance-associated CaPR1, CaNPR1, CaDEF1, and CaHSP24. Hypersensitive response-mediated cell death and expression of the tested immunity- and thermotolerance-associated marker genes were induced by transient overexpression (TOE) of CabZIP63, but decreased by that of CabZIP63-SRDX. Additionally, binding of CabZIP63 to pCaWRKY40 was up-regulated by RSI or HTHH, and the transcript level of CaWRKY40 and binding of CaWRKY40 to the promoters of CaPR1, CaNPR1, CaDEF1 and CaHSP24 were up-regulated by TOE of CabZIP63. On the other hand, CabZIP63 was also up-regulated transcriptionally by TOE of CaWRKY40. The data suggest collectively that CabZIP63 directly or indirectly regulates the expression of CaWRKY40 at both the transcriptional and post-transcriptional level, forming a positive feedback loop with CaWRKY40 during pepper's response to RSI or HTHH. Altogether, our data will help to elucidate the underlying mechanism of crosstalk between pepper's response to RSI and HTHH. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Does it really matter that people zip through ads? Testing the effectiveness of simultaneous presentation advertising in an IDTV environment.

PubMed

Nam, Yoonjae; Kwon, Kyonghee H; Lee, Sungjoon

2010-04-01

In an IDTV environment, which facilitates self-scheduling, skipping advertisements by zipping is an emerging ad-avoidance behavior. This study explores whether an alternative ad format, called simultaneous presentation advertising (SPA), may overcome the limitations of classical sequential advertising (CSA) in controlling zipping behavior and increasing the effectiveness of ads. The experiment revealed that SPA is more effective than CSA in reducing zipping and increasing recall, but SPA was more intrusive and produced a negative product image. There was no difference regarding cognitive avoidance. This work discusses the implications of these findings in the interactive media environment.

Algorithm Calculates Cumulative Poisson Distribution

NASA Technical Reports Server (NTRS)

Bowerman, Paul N.; Nolty, Robert C.; Scheuer, Ernest M.

1992-01-01

Algorithm calculates accurate values of cumulative Poisson distribution under conditions where other algorithms fail because numbers are so small (underflow) or so large (overflow) that computer cannot process them. Factors inserted temporarily to prevent underflow and overflow. Implemented in CUMPOIS computer program described in "Cumulative Poisson Distribution Program" (NPO-17714).

Accident prediction model for public highway-rail grade crossings.

PubMed

Lu, Pan; Tolliver, Denver

2016-05-01

Considerable research has focused on roadway accident frequency analysis, but relatively little research has examined safety evaluation at highway-rail grade crossings. Highway-rail grade crossings are critical spatial locations of utmost importance for transportation safety because traffic crashes at highway-rail grade crossings are often catastrophic with serious consequences. The Poisson regression model has been employed to analyze vehicle accident frequency as a good starting point for many years. The most commonly applied variations of Poisson including negative binomial, and zero-inflated Poisson. These models are used to deal with common crash data issues such as over-dispersion (sample variance is larger than the sample mean) and preponderance of zeros (low sample mean and small sample size). On rare occasions traffic crash data have been shown to be under-dispersed (sample variance is smaller than the sample mean) and traditional distributions such as Poisson or negative binomial cannot handle under-dispersion well. The objective of this study is to investigate and compare various alternate highway-rail grade crossing accident frequency models that can handle the under-dispersion issue. The contributions of the paper are two-fold: (1) application of probability models to deal with under-dispersion issues and (2) obtain insights regarding to vehicle crashes at public highway-rail grade crossings. Copyright © 2016 Elsevier Ltd. All rights reserved.

DNA Methylation Influences Chlorogenic Acid Biosynthesis in Lonicera japonica by Mediating LjbZIP8 to Regulate Phenylalanine Ammonia-Lyase 2 Expression

PubMed Central

Zha, Liangping; Liu, Shuang; Liu, Juan; Jiang, Chao; Yu, Shulin; Yuan, Yuan; Yang, Jian; Wang, Yaolong; Huang, Luqi

2017-01-01

The content of active compounds differ in buds and flowers of Lonicera japonica (FLJ) and L. japonica var. chinensis (rFLJ). Chlorogenic acid (CGAs) were major active compounds of L. japonica and regarded as measurements for quality evaluation. However, little is known concerning the formation of active compounds at the molecular level. We quantified the major CGAs in FLJ and rFLJ, and found the concentrations of CGAs were higher in the buds of rFLJ than those of FLJ. Further analysis of CpG methylation of CGAs biosynthesis genes showed differences between FLJ and rFLJ in the 5′-UTR of phenylalanine ammonia-lyase 2 (PAL2). We identified 11 LjbZIP proteins and 24 rLjbZIP proteins with conserved basic leucine zipper domains, subcellular localization, and electrophoretic mobility shift assay showed that the transcription factor LjbZIP8 is a nuclear-localized protein that specifically binds to the G-box element of the LjPAL2 5′-UTR. Additionally, a transactivation assay and LjbZIP8 overexpression in transgenic tobacco indicated that LjbZIP8 could function as a repressor of transcription. Finally, treatment with 5-azacytidine decreased the transcription level of LjPAL2 and CGAs content in FLJ leaves. These results raise the possibility that DNA methylation might influence the recruitment of LjbZIP8, regulating PAL2 expression level and CGAs content in L. japonica. PMID:28740500

Modeling zero-modified count and semicontinuous data in health services research Part 1: background and overview.

PubMed

Neelon, Brian; O'Malley, A James; Smith, Valerie A

2016-11-30

Health services data often contain a high proportion of zeros. In studies examining patient hospitalization rates, for instance, many patients will have no hospitalizations, resulting in a count of zero. When the number of zeros is greater or less than expected under a standard count model, the data are said to be zero modified relative to the standard model. A similar phenomenon arises with semicontinuous data, which are characterized by a spike at zero followed by a continuous distribution with positive support. When analyzing zero-modified count and semicontinuous data, flexible mixture distributions are often needed to accommodate both the excess zeros and the typically skewed distribution of nonzero values. Various models have been introduced over the past three decades to accommodate such data, including hurdle models, zero-inflated models, and two-part semicontinuous models. This tutorial describes recent modeling strategies for zero-modified count and semicontinuous data and highlights their role in health services research studies. Part 1 of the tutorial, presented here, provides a general overview of the topic. Part 2, appearing as a companion piece in this issue of Statistics in Medicine, discusses three case studies illustrating applications of the methods to health services research. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Topological defects in extended inflation

NASA Technical Reports Server (NTRS)

Copeland, Edmund J.; Kolb, Edward W.; Liddle, Andrew R.

1990-01-01

The production of topological defects, especially cosmic strings, in extended inflation models was considered. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of bubbles when they collide. This mechanism allows a natural combination of inflation and large scale structure via cosmic strings.

Engineering of a novel zipFv using leucine zipper motif against rabies virus glycoprotein G with improved protection potency in vivo.

PubMed

Xi, Hualong; Zhang, Kaixin; Yin, Yanchun; Gu, Tiejun; Sun, Qing; Li, Zhuang; Cheng, Yue; Jiang, Chunlai; Kong, Wei; Wu, Yongge

2017-06-01

Rabies is an acute zoonotic infectious disease with a high fatality rate but is preventable with vaccination and rabies immunoglobulin (RIG). The single-chain Fv fragment (scFv), a small engineered antigen-binding protein derived from antibody variable heavy (V H ) and light (V L ) chains connected by a peptide linker, can potentially be used to replace RIG. Here, we produced two peptides V H -JUN-HIS and V L -FOS-HA separately in Escherichia coli and assembled them to form zipFv successfully in vitro. The new zipFv utilizes FOS and JUN leucine zippers to form an antibody structure similar to the IgG counterpart with two free N-terminal ends of V H and V L . The zipFv protein showed notable improvement in binding ability and affinity over its corresponding scFv. The zipFv also demonstrated greater stability in serum and the same protective rate as RIG against challenge with a standard rabies virus (CVS-24) in mice. Our results indicated zipFv as a novel and efficient antibody form with enhanced neutralizing potency. Copyright © 2017. Published by Elsevier B.V.

Tribrid Inflation in Supergravity

NASA Astrophysics Data System (ADS)

Antusch, Stefan; Dutta, Koushik; Kostka, Philipp M.

We propose a novel class of F-term hybrid inflation models in supergravity (SUGRA) where the η-problem is resolved using either a Heisenberg symmetry or a shift symmetry of the Kähler potential. In addition to the inflaton and the waterfall field, this class (referred to as tribrid inflation) contains a third "driving" field which contributes the large vacuum energy during inflation by its F-term. In contrast to the "standard" hybrid scenario, it has several attractive features due to the property of vanishing inflationary superpotential (Winf = 0) during inflation. Quantum corrections induced by symmetry breaking terms in the superpotential generate a slope of the potential and lead to a spectral tilt consistent with recent WMAP observations.

Statistical procedures for analyzing mental health services data.

PubMed

Elhai, Jon D; Calhoun, Patrick S; Ford, Julian D

2008-08-15

In mental health services research, analyzing service utilization data often poses serious problems, given the presence of substantially skewed data distributions. This article presents a non-technical introduction to statistical methods specifically designed to handle the complexly distributed datasets that represent mental health service use, including Poisson, negative binomial, zero-inflated, and zero-truncated regression models. A flowchart is provided to assist the investigator in selecting the most appropriate method. Finally, a dataset of mental health service use reported by medical patients is described, and a comparison of results across several different statistical methods is presented. Implications of matching data analytic techniques appropriately with the often complexly distributed datasets of mental health services utilization variables are discussed.

Stochastic effects in hybrid inflation

NASA Astrophysics Data System (ADS)

Martin, Jérôme; Vennin, Vincent

2012-02-01

Hybrid inflation is a two-field model where inflation ends due to an instability. In the neighborhood of the instability point, the potential is very flat and the quantum fluctuations dominate over the classical motion of the inflaton and waterfall fields. In this article, we study this regime in the framework of stochastic inflation. We numerically solve the two coupled Langevin equations controlling the evolution of the fields and compute the probability distributions of the total number of e-folds and of the inflation exit point. Then, we discuss the physical consequences of our results, in particular, the question of how the quantum diffusion can affect the observable predictions of hybrid inflation.

Computing travel time when the exact address is unknown: a comparison of point and polygon ZIP code approximation methods.

PubMed

Berke, Ethan M; Shi, Xun

2009-04-29

Travel time is an important metric of geographic access to health care. We compared strategies of estimating travel times when only subject ZIP code data were available. Using simulated data from New Hampshire and Arizona, we estimated travel times to nearest cancer centers by using: 1) geometric centroid of ZIP code polygons as origins, 2) population centroids as origin, 3) service area rings around each cancer center, assigning subjects to rings by assuming they are evenly distributed within their ZIP code, 4) service area rings around each center, assuming the subjects follow the population distribution within the ZIP code. We used travel times based on street addresses as true values to validate estimates. Population-based methods have smaller errors than geometry-based methods. Within categories (geometry or population), centroid and service area methods have similar errors. Errors are smaller in urban areas than in rural areas. Population-based methods are superior to the geometry-based methods, with the population centroid method appearing to be the best choice for estimating travel time. Estimates in rural areas are less reliable.

Calculation of the Poisson cumulative distribution function

NASA Technical Reports Server (NTRS)

Bowerman, Paul N.; Nolty, Robert G.; Scheuer, Ernest M.

1990-01-01

A method for calculating the Poisson cdf (cumulative distribution function) is presented. The method avoids computer underflow and overflow during the process. The computer program uses this technique to calculate the Poisson cdf for arbitrary inputs. An algorithm that determines the Poisson parameter required to yield a specified value of the cdf is presented.

Graphic Simulations of the Poisson Process.

DTIC Science & Technology

1982-10-01

RANDOM NUMBERS AND TRANSFORMATIONS..o......... 11 Go THE RANDOM NUMBERGENERATOR....... .oo..... 15 III. POISSON PROCESSES USER GUIDE....oo.ooo ......... o...again. In the superimposed mode, two Poisson processes are active, each with a different rate parameter, (call them Type I and Type II with respective...occur. The value ’p’ is generated by the following equation where ’Li’ and ’L2’ are the rates of the two Poisson processes ; p = Li / (Li + L2) The value

Inflatable robotics for planetary applications

NASA Technical Reports Server (NTRS)

Jones, Jack A.

2001-01-01

Space Inflatable vehicles have been finding popularity in recent years for applications as varied as spacecraft antennas, space-based telescopes, solar sails, and manned habitats [1]. Another branch of space inflatable technology has also considered developing ambient gasfilled, solar balloons for Mars as well as ambient gasfilled inflatable rovers [2]. More recently, some other intriguing space-inflatable vehicles have been proposed for the gas planets and Pluto, as well as for Saturn's moon, Titan, Neptune's moon, Triton, and Jupiter's moon, Io [3].

Poisson Spot with Magnetic Levitation

ERIC Educational Resources Information Center

Hoover, Matthew; Everhart, Michael; D'Arruda, Jose

2010-01-01

In this paper we describe a unique method for obtaining the famous Poisson spot without adding obstacles to the light path, which could interfere with the effect. A Poisson spot is the interference effect from parallel rays of light diffracting around a solid spherical object, creating a bright spot in the center of the shadow.

Degravitation, inflation and the cosmological constant as an afterglow

NASA Astrophysics Data System (ADS)

Patil, Subodh P.

2009-01-01

In this report, we adopt the phenomenological approach of taking the degravitation paradigm seriously as a consistent modification of gravity in the IR, and investigate its consequences for various cosmological situations. We motivate degravitation — where Netwon's constant is promoted to a scale dependent filter function — as arising from either a small (resonant) mass for the graviton, or as an effect in semi-classical gravity. After addressing how the Bianchi identities are to be satisfied in such a set up, we turn our attention towards the cosmological consequences of degravitation. By considering the example filter function corresponding to a resonantly massive graviton (with a filter scale larger than the present horizon scale), we show that slow roll inflation, hybrid inflation and old inflation remain quantitatively unchanged. We also find that the degravitation mechanism inherits a memory of past energy densities in the present epoch in such a way that is likely significant for present cosmological evolution. For example, if the universe underwent inflation in the past due to it having tunneled out of some false vacuum, we find that degravitation implies a remnant `afterglow' cosmological constant, whose scale immediately afterwards is parametrically suppressed by the filter scale (L) in Planck units Λ ~ l2pl/L2. We discuss circumstances through which this scenario reasonably yields the presently observed value for Λ ~ O(10-120). We also find that in a universe still currently trapped in some false vacuum state, resonance graviton models of degravitation only degravitate initially Planck or GUT scale energy densities down to the presently observed value over timescales comparable to the filter scale. We argue that different functional forms for the filter function will yield similar conclusions. In this way, we argue that although the degravitation models we study have the potential to explain why the cosmological constant is not large in addition to

Map scale effects on estimating the number of undiscovered mineral deposits

USGS Publications Warehouse

Singer, D.A.; Menzie, W.D.

2008-01-01

Estimates of numbers of undiscovered mineral deposits, fundamental to assessing mineral resources, are affected by map scale. Where consistently defined deposits of a particular type are estimated, spatial and frequency distributions of deposits are linked in that some frequency distributions can be generated by processes randomly in space whereas others are generated by processes suggesting clustering in space. Possible spatial distributions of mineral deposits and their related frequency distributions are affected by map scale and associated inclusions of non-permissive or covered geological settings. More generalized map scales are more likely to cause inclusion of geologic settings that are not really permissive for the deposit type, or that include unreported cover over permissive areas, resulting in the appearance of deposit clustering. Thus, overly generalized map scales can cause deposits to appear clustered. We propose a model that captures the effects of map scale and the related inclusion of non-permissive geologic settings on numbers of deposits estimates, the zero-inflated Poisson distribution. Effects of map scale as represented by the zero-inflated Poisson distribution suggest that the appearance of deposit clustering should diminish as mapping becomes more detailed because the number of inflated zeros would decrease with more detailed maps. Based on observed worldwide relationships between map scale and areas permissive for deposit types, mapping at a scale with twice the detail should cut permissive area size of a porphyry copper tract to 29% and a volcanic-hosted massive sulfide tract to 50% of their original sizes. Thus some direct benefits of mapping an area at a more detailed scale are indicated by significant reductions in areas permissive for deposit types, increased deposit density and, as a consequence, reduced uncertainty in the estimate of number of undiscovered deposits. Exploration enterprises benefit from reduced areas requiring

Newton/Poisson-Distribution Program

NASA Technical Reports Server (NTRS)

Bowerman, Paul N.; Scheuer, Ernest M.

1990-01-01

NEWTPOIS, one of two computer programs making calculations involving cumulative Poisson distributions. NEWTPOIS (NPO-17715) and CUMPOIS (NPO-17714) used independently of one another. NEWTPOIS determines Poisson parameter for given cumulative probability, from which one obtains percentiles for gamma distributions with integer shape parameters and percentiles for X(sup2) distributions with even degrees of freedom. Used by statisticians and others concerned with probabilities of independent events occurring over specific units of time, area, or volume. Program written in C.

12 CFR 19.240 - Inflation adjustments.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Inflation adjustments. 19.240 Section 19.240... PROCEDURE Civil Money Penalty Inflation Adjustments § 19.240 Inflation adjustments. (a) The maximum amount... Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note) as follows: ER10NO08.001 (b) The...

A new method for the construction of a mutant library with a predictable occurrence rate using Poisson distribution.

PubMed

Seong, Ki Moon; Park, Hweon; Kim, Seong Jung; Ha, Hyo Nam; Lee, Jae Yung; Kim, Joon

2007-06-01

A yeast transcriptional activator, Gcn4p, induces the expression of genes that are involved in amino acid and purine biosynthetic pathways under amino acid starvation. Gcn4p has an acidic activation domain in the central region and a bZIP domain in the C-terminus that is divided into the DNA-binding motif and dimerization leucine zipper motif. In order to identify amino acids in the DNA-binding motif of Gcn4p which are involved in transcriptional activation, we constructed mutant libraries in the DNA-binding motif through an innovative application of random mutagenesis. Mutant library made by oligonucleotides which were mutated randomly using the Poisson distribution showed that the actual mutation frequency was in good agreement with expected values. This method could save the time and effort to create a mutant library with a predictable mutation frequency. Based on the studies using the mutant libraries constructed by the new method, the specific residues of the DNA-binding domain in Gcn4p appear to be involved in the transcriptional activities on a conserved binding site.

Aerocapture Inflatable Decelerator (AID)

NASA Technical Reports Server (NTRS)

Reza, Sajjad

2007-01-01

Forward Attached Inflatable Decelerators, more commonly known as inflatable aeroshells, provide an effective, cost efficient means of decelerating spacecrafts by using atmospheric drag for aerocapture or planetary entry instead of conventional liquid propulsion deceleration systems. Entry into planetary atmospheres results in significant heating and aerodynamic pressures which stress aeroshell systems to their useful limits. Incorporation of lightweight inflatable decelerator surfaces with increased surface-area footprints provides the opportunity to reduce heat flux and induced temperatures, while increasing the payload mass fraction. Furthermore, inflatable aeroshell decelerators provide the needed deceleration at considerably higher altitudes and Mach numbers when compared with conventional rigid aeroshell entry systems. Inflatable aeroshells also provide for stowage in a compact space, with subsequent deployment of a large-area, lightweight heatshield to survive entry heating. Use of a deployable heatshield decelerator not only enables an increase in the spacecraft payload mass fraction and but may also eliminate the need for a spacecraft backshell and cruise stage. This document is the viewgraph slides for the paper's presentation.

Mutated hilltop inflation revisited

NASA Astrophysics Data System (ADS)

Pal, Barun Kumar

2018-05-01

In this work we re-investigate pros and cons of mutated hilltop inflation. Applying Hamilton-Jacobi formalism we solve inflationary dynamics and find that inflation goes on along the {W}_{-1} branch of the Lambert function. Depending on the model parameter mutated hilltop model renders two types of inflationary solutions: one corresponds to small inflaton excursion during observable inflation and the other describes large field inflation. The inflationary observables from curvature perturbation are in tune with the current data for a wide range of the model parameter. The small field branch predicts negligible amount of tensor to scalar ratio r˜ O(10^{-4}), while the large field sector is capable of generating high amplitude for tensor perturbations, r˜ O(10^{-1}). Also, the spectral index is almost independent of the model parameter along with a very small negative amount of scalar running. Finally we find that the mutated hilltop inflation closely resembles the α -attractor class of inflationary models in the limit of α φ ≫ 1.

A Martingale Characterization of Mixed Poisson Processes.

DTIC Science & Technology

1985-10-01

03LA A 11. TITLE (Inciuae Security Clanafication, ",A martingale characterization of mixed Poisson processes " ________________ 12. PERSONAL AUTHOR... POISSON PROCESSES Jostification .......... . ... . . Di.;t ib,,jtion by Availability Codes Dietmar Pfeifer* Technical University Aachen Dist Special and...Mixed Poisson processes play an important role in many branches of applied probability, for instance in insurance mathematics and physics (see Albrecht

General methodology for nonlinear modeling of neural systems with Poisson point-process inputs.

PubMed

Marmarelis, V Z; Berger, T W

2005-07-01

This paper presents a general methodological framework for the practical modeling of neural systems with point-process inputs (sequences of action potentials or, more broadly, identical events) based on the Volterra and Wiener theories of functional expansions and system identification. The paper clarifies the distinctions between Volterra and Wiener kernels obtained from Poisson point-process inputs. It shows that only the Wiener kernels can be estimated via cross-correlation, but must be defined as zero along the diagonals. The Volterra kernels can be estimated far more accurately (and from shorter data-records) by use of the Laguerre expansion technique adapted to point-process inputs, and they are independent of the mean rate of stimulation (unlike their P-W counterparts that depend on it). The Volterra kernels can also be estimated for broadband point-process inputs that are not Poisson. Useful applications of this modeling approach include cases where we seek to determine (model) the transfer characteristics between one neuronal axon (a point-process 'input') and another axon (a point-process 'output') or some other measure of neuronal activity (a continuous 'output', such as population activity) with which a causal link exists.

Dark zone in the centre of the Arago-Poisson diffraction spot of a helical laser beam

NASA Astrophysics Data System (ADS)

Emile, O.; Voisin, A.; Niemiec, R.; Viaris de Lesegno, B.; Pruvost, L.; Ropars, G.; Emile, J.; Brousseau, C.

2013-03-01

We report on the diffraction of non-zero Laguerre Gaussian laser beams by an opaque disk. We observe a tiny circular dark zone at the centre of the usual Arago-Poisson diffraction bright spot. For such non-diffracting dark hollow beams, we have measured diameters as small as 20 μm on distances of the order of ten metres, without focalization. Diameters depend on the diffracting object size and on the topological charge of the input Laguerre Gaussian beam. These results are in good agreement with theoretical considerations. Potential applications are then discussed.

No-scale ripple inflation revisited

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Tianjun; Li, Zhijin; Nanopoulos, Dimitri V., E-mail: tli@itp.ac.cn, E-mail: lizhijin@physics.tamu.edu, E-mail: dimitri@physics.tamu.edu

We revisit the no-scale ripple inflation model, where no-scale supergravity is modified by an additional term for the inflaton field in the Kähler potential. This term not only breaks one SU(N,1) symmetry explicitly, but also plays an important role for inflation. We generalize the superpotential in the no-scale ripple inflation model slightly. There exists a discrete Z{sub 2} symmetry/parity in the scalar potential in general, which can be preserved or violated by the non-canonical nomalized inflaton kinetic term. Thus, there are three inflation paths: one parity invariant path, and the left and right paths for parity violating scenario. We showmore » that the inflations along the parity invariant path and right path are consistent with the Planck results. However, the gavitino mass for the parity invariant path is so large that the inflation results will be invalid if we consider the inflaton supersymmetry breaking soft mass term. Thus, only the inflation along the right path gives the correct and consistent results. Notably, the tensor-to-scalar ratio in such case can be large, with a value around 0.05, which may be probed by the future Planck experiment.« less

Paretian Poisson Processes

NASA Astrophysics Data System (ADS)

Eliazar, Iddo; Klafter, Joseph

2008-05-01

Many random populations can be modeled as a countable set of points scattered randomly on the positive half-line. The points may represent magnitudes of earthquakes and tornados, masses of stars, market values of public companies, etc. In this article we explore a specific class of random such populations we coin ` Paretian Poisson processes'. This class is elemental in statistical physics—connecting together, in a deep and fundamental way, diverse issues including: the Poisson distribution of the Law of Small Numbers; Paretian tail statistics; the Fréchet distribution of Extreme Value Theory; the one-sided Lévy distribution of the Central Limit Theorem; scale-invariance, renormalization and fractality; resilience to random perturbations.

Membrane androgen receptor characteristics of human ZIP9 (SLC39A) zinc transporter in prostate cancer cells: Androgen-specific activation and involvement of an inhibitory G protein in zinc and MAP kinase signaling.

PubMed

Thomas, Peter; Pang, Yefei; Dong, Jing

2017-05-15

Characteristics of novel human membrane androgen receptor (mAR), ZIP9 (SLC39A9), were investigated in ZIP9-transfected PC-3 cells (PC3-ZIP9). Ligand blot analysis showed plasma membrane [ 3 H]-T binding corresponds to the position of ZIP9 on Western blots which suggests ZIP9 can bind [ 3 H]-T alone, without a protein partner. Progesterone antagonized testosterone actions, blocking increases in zinc, Erk phosphorylation and apoptosis, further evidence that ZIP9 is specifically activated by androgens. Pre-treatment with GTPγS and pertussis toxin decreased plasma membrane [ 3 H]-T binding and blocked testosterone-induced increases in Erk phosphorylation and intracellular zinc, indicating ZIP9 is coupled to an inhibitory G protein (Gi) that mediates both MAP kinase and zinc signaling. Testosterone treatment of nuclei and mitochondria which express ZIP9 decreased their zinc contents, suggesting ZIP9 also regulates free zinc through releasing it from these intracellular organelles. The results show ZIP9 is a specific Gi coupled-mAR mediating testosterone-induced MAP kinase and zinc signaling in PC3-ZIP9 cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Testing Cosmic Inflation

NASA Technical Reports Server (NTRS)

Chuss, David

2010-01-01

The Cosmic Microwave Background (CMB) has provided a wealth of information about the history and physics of the early Universe. Much progress has been made on uncovering the emerging Standard Model of Cosmology by such experiments as COBE and WMAP, and ESA's Planck Surveyor will likely increase our knowledge even more. Despite the success of this model, mysteries remain. Currently understood physics does not offer a compelling explanation for the homogeneity, flatness, and the origin of structure in the Universe. Cosmic Inflation, a brief epoch of exponential expansion, has been posted to explain these observations. If inflation is a reality, it is expected to produce a background spectrum of gravitational waves that will leave a small polarized imprint on the CMB. Discovery of this signal would give the first direct evidence for inflation and provide a window into physics at scales beyond those accessible to terrestrial particle accelerators. I will briefly review aspects of the Standard Model of Cosmology and discuss our current efforts to design and deploy experiments to measure the polarization of the CMB with the precision required to test inflation.

First-order inflation. [in cosmology

NASA Technical Reports Server (NTRS)

Turner, Michael S.

1992-01-01

I discuss the most recent model of inflation. In first-order inflation the inflationary epoch is associated with a first-order phase transition, with the most likely candidate being GUT symmetry breaking. The transition from the false-vacuum inflationary phase to the true-vacuum radiation-dominated phase proceeds through the nucleation and percolation of true-vacuum bubbles. The first successful and simplest model of first-order inflation, extended inflation, is discussed in some detail: evolution of the cosmic-scale factor, reheating, density perturbations, and the production of gravitational waves both from quantum fluctuations and bubble collisions. Particular attention is paid to the most critical issue in any model of first-order inflation: the requirements on the nucleation rate to ensure a graceful transition from the inflationary phase to the radiation-dominated phase.

Poisson's spot and Gouy phase

NASA Astrophysics Data System (ADS)

da Paz, I. G.; Soldati, Rodolfo; Cabral, L. A.; de Oliveira, J. G. G.; Sampaio, Marcos

2016-12-01

Recently there have been experimental results on Poisson spot matter-wave interferometry followed by theoretical models describing the relative importance of the wave and particle behaviors for the phenomenon. We propose an analytical theoretical model for Poisson's spot with matter waves based on the Babinet principle, in which we use the results for free propagation and single-slit diffraction. We take into account effects of loss of coherence and finite detection area using the propagator for a quantum particle interacting with an environment. We observe that the matter-wave Gouy phase plays a role in the existence of the central peak and thus corroborates the predominantly wavelike character of the Poisson's spot. Our model shows remarkable agreement with the experimental data for deuterium (D2) molecules.

Microwave background anisotropies in quasiopen inflation

NASA Astrophysics Data System (ADS)

García-Bellido, Juan; Garriga, Jaume; Montes, Xavier

1999-10-01

Quasiopenness seems to be generic to multifield models of single-bubble open inflation. Instead of producing infinite open universes, these models actually produce an ensemble of very large but finite inflating islands. In this paper we study the possible constraints from CMB anisotropies on existing models of open inflation. The effect of supercurvature anisotropies combined with the quasiopenness of the inflating regions make some models incompatible with observations, and severely reduces the parameter space of others. Supernatural open inflation and the uncoupled two-field model seem to be ruled out due to these constraints for values of Ω0<~0.98. Others, such as the open hybrid inflation model with suitable parameters for the slow roll potential can be made compatible with observations.

IAE - Inflatable Antenna Experiment

NASA Image and Video Library

1996-06-10

STS077-705-051 (20 May 1996) --- Following its deployment from the Space Shuttle Endeavour and its subsequent inflation process, the Spartan 207/Inflatable Antenna Experiment (IAE) payload is backdropped over mountains. The view was photographed with a handheld 70mm camera during the first full day of orbital operations by the six-member crew. Managed by Goddard Space Flight Center (GSFC), Spartan is designed to provide short-duration, free-flight opportunities for a variety of scientific studies. The Spartan configuration on this flight is unique in that the IAE is part of an additional separate unit which is ejected once the experiment is completed. The IAE experiment will lay the groundwork for future technology development in inflatable space structures, which will be launched and then inflated like a balloon on-orbit.

IAE - Inflatable Antenna Experiment

NASA Image and Video Library

1996-05-20

STS077-150-010 (20 May 1996) --- Soon after leaving the cargo bay of the Space Shuttle Endeavour, the Spartan 207/Inflatable Antenna Experiment (IAE) payload goes through its inflation process, backdropped over clouds. The view was photographed with a large format still camera on the first full day of in-space operations by the six-member crew. Managed by Goddard Space Flight Center (GSFC), Spartan is designed to provide short-duration, free-flight opportunities for a variety of scientific studies. The Spartan configuration on this flight is unique in that the IAE is part of an additional separate unit which is ejected once the experiment is completed. The IAE experiment will lay the groundwork for future technology development in inflatable space structures, which will be launched and then inflated like a balloon on-orbit.

Cosmological perturbations and noncommutative tachyon inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Daojun; Li Xinzhou

2004-12-15

The motivation for studying the rolling tachyon and noncommutative inflation comes from string theory. In the tachyon inflation scenario, metric perturbations are created by tachyon field fluctuations during inflation. We drive the exact mode equation for scalar perturbations of the metric and investigate the cosmological perturbations in the commutative and noncommutative inflationary spacetime driven by the tachyon field which have a Born-Infeld Lagrangian. Although at lowest order the predictions of tachyon inflation are no different than those from standard slow-roll inflation, due to the modified inflationary dynamics there exists modifications to the power spectra of fluctuations generated during inflation. Inmore » the noncommutative tachyon inflation scenario, the stringy noncommutativity of spacetime results in corrections to the primordial power spectrum that lead to a spectral index that is greater than 1 on large scales and less than 1 on small scales as the first-year results of the Wilkinson Microwave Anisotropy Probe indicate.« less

Oxidative stress upregulates zinc uptake activity via Zrt/Irt-like protein 1 (ZIP1) in cultured mouse astrocytes.

PubMed

Furuta, Takahiro; Ohshima, Chiaki; Matsumura, Mayu; Takebayashi, Naoto; Hirota, Emi; Mawaribuchi, Toshiki; Nishida, Kentaro; Nagasawa, Kazuki

2016-04-15

Zinc released from glutamatergic boutons and astrocytes acts as neuro- and glio-transmitters, and thus its extracellular level has to be strictly regulated. We previously revealed that uptake of zinc by astrocytes plays a critical role in its clearance, and zinc transporter Zrt/Irt-like protein 1 (ZIP1) is the molecule responsible for the uptake. However, it is unknown whether or not the functionality of the zinc clearance system is altered under oxidative stress-loaded conditions. Here, we characterized zinc uptake by oxidative stress-loaded astrocytes. Cultured mouse astrocytes were treated with hydrogen peroxide (H2O2) to load oxidative stress. Functional expression of ZIP1 in astrocytes was evaluated by means of (65)Zn uptake, Western blotting and immunocytochemical analysis. Treatment of astrocytes with 0.4mM H2O2 for 24h increased the expression levels of glial fibrillary acidic protein and 4-hydroxynonenal without significant decreases in their viability, indicating that induction of oxidative stress in astrocytes. Under oxidative stress-loaded conditions, astrocytes exhibited increased (65)Zn uptake activity, and the maximum uptake velocity for the uptake was significantly increased compared to that in the control group, while there was no change in the Michaelis constants, which were almost identical to that of mouse ZIP1. In the H2O2-treated astrocytes, the expression levels of ZIP1 were significantly increased in the cellular and plasma membrane fractions. It appears that under oxidative stress-loaded conditions, astrocytes exhibit increased zinc clearance activity and this is due, at least in part, to increased ZIP1 expression. Copyright © 2016 Elsevier Inc. All rights reserved.

Attachment device for an inflatable protective cushion

DOEpatents

Nelsen, J.M.; Luna, D.A.; Gwinn, K.W.

1997-11-18

An inflatable cushion assembly for use with an inflator comprises an inflatable cushion having an inner surface, outer surface, and at least one protrusion extending from one of the inner or outer surfaces. The inflatable cushion defines an opening between the inner surface and the outer surface for receiving the inflator. An attachment member contacts the one of the inner or outer surfaces adjacent the opening and includes a groove for receiving the protrusion, the attachment member securing the inflator within the opening. 22 figs.

Attachment device for an inflatable protective cushion

DOEpatents

Nelsen, J.M.; Luna, D.A.; Gwinn, K.W.

1998-12-08

An inflatable cushion assembly for use with an inflator comprises an inflatable cushion having an inner surface, outer surface, and at least one protrusion extending from one of the inner or outer surfaces. The inflatable cushion defines an opening between the inner surface and the outer surface for receiving the inflator. An attachment member contacts the one of the inner or outer surfaces adjacent the opening and includes a groove for receiving the protrusion, the attachment member securing the inflator within the opening. 22 figs.

Unimodularity criteria for Poisson structures on foliated manifolds

NASA Astrophysics Data System (ADS)

Pedroza, Andrés; Velasco-Barreras, Eduardo; Vorobiev, Yury

2018-03-01

We study the behavior of the modular class of an orientable Poisson manifold and formulate some unimodularity criteria in the semilocal context, around a (singular) symplectic leaf. Our results generalize some known unimodularity criteria for regular Poisson manifolds related to the notion of the Reeb class. In particular, we show that the unimodularity of the transverse Poisson structure of the leaf is a necessary condition for the semilocal unimodular property. Our main tool is an explicit formula for a bigraded decomposition of modular vector fields of a coupling Poisson structure on a foliated manifold. Moreover, we also exploit the notion of the modular class of a Poisson foliation and its relationship with the Reeb class.

Inflation at the electroweak scale

NASA Technical Reports Server (NTRS)

Knox, Lloyd; Turner, Michael S.

1993-01-01

We present a model for slow-rollover inflation where the vacuum energy that drives inflation is of the order of G(F) exp -2; unlike most models, the conversion of vacuum energy to radiation ('reheating') is moderately efficient. The scalar field responsible for inflation is a standard-model singlet, develops a vacuum expectation value of 4 x 10 exp 6 GeV, has a mass of about 1 GeV, and can play a role in electroweak phenomena. We also discuss models where the energy scale of inflation is somewhat larger, but still well below the unification scale.

77 FR 18716 - Transportation Security Administration Postal Zip Code Change; Technical Amendment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-28

... organizational changes and it has no substantive effect on the public. DATES: Effective March 28, 2012. FOR... No. 1572-9] Transportation Security Administration Postal Zip Code Change; Technical Amendment AGENCY: Transportation Security Administration, DHS. ACTION: Final rule. SUMMARY: This rule is a technical change to...

Characterization of Nonhomogeneous Poisson Processes Via Moment Conditions.

DTIC Science & Technology

1986-08-01

Poisson processes play an important role in many fields. The Poisson process is one of the simplest counting processes and is a building block for...place of independent increments. This provides a somewhat different viewpoint for examining Poisson processes . In addition, new characterizations for

Advanced Structural and Inflatable Hybrid Spacecraft Module

NASA Technical Reports Server (NTRS)

Schneider, William C. (Inventor); delaFuente, Horacio M. (Inventor); Edeen, Gregg A. (Inventor); Kennedy, Kriss J. (Inventor); Lester, James D. (Inventor); Gupta, Shalini (Inventor); Hess, Linda F. (Inventor); Lin, Chin H. (Inventor); Malecki, Richard H. (Inventor); Raboin, Jasen L. (Inventor)

2001-01-01

An inflatable module comprising a structural core and an inflatable shell, wherein the inflatable shell is sealingly attached to the structural core. In its launch configuration, the wall thickness of the inflatable shell is collapsed by vacuum. Also in this configuration, the inflatable shell is collapsed and efficiently folded around the structural core. Upon deployment, the wall thickness of the inflatable shell is inflated; whereby the inflatable shell itself, is thereby inflated around the structural core, defining therein a large enclosed volume. A plurality of removable shelves are arranged interior to the structural core in the launch configuration. The structural core also includes at least one longeron that, in conjunction with the shelves, primarily constitute the rigid, strong, and lightweight load-bearing structure of the module during launch. The removable shelves are detachable from their arrangement in the launch configuration so that, when the module is in its deployed configuration and launch loads no longer exist, the shelves can be rearranged to provide a module interior arrangement suitable for human habitation and work. In the preferred embodiment, to provide efficiency in structural load paths and attachments, the shape of the inflatable shell is a cylinder with semi-toroidal ends.

Poisson geometry from a Dirac perspective

NASA Astrophysics Data System (ADS)

Meinrenken, Eckhard

2018-03-01

We present proofs of classical results in Poisson geometry using techniques from Dirac geometry. This article is based on mini-courses at the Poisson summer school in Geneva, June 2016, and at the workshop Quantum Groups and Gravity at the University of Waterloo, April 2016.

Information transmission using non-poisson regular firing.

PubMed

Koyama, Shinsuke; Omi, Takahiro; Kass, Robert E; Shinomoto, Shigeru

2013-04-01

In many cortical areas, neural spike trains do not follow a Poisson process. In this study, we investigate a possible benefit of non-Poisson spiking for information transmission by studying the minimal rate fluctuation that can be detected by a Bayesian estimator. The idea is that an inhomogeneous Poisson process may make it difficult for downstream decoders to resolve subtle changes in rate fluctuation, but by using a more regular non-Poisson process, the nervous system can make rate fluctuations easier to detect. We evaluate the degree to which regular firing reduces the rate fluctuation detection threshold. We find that the threshold for detection is reduced in proportion to the coefficient of variation of interspike intervals.

The relationship between inflation and inflation uncertainty. Empirical evidence for the newest EU countries.

PubMed

Viorica, Daniela; Jemna, Danut; Pintilescu, Carmen; Asandului, Mircea

2014-01-01

The objective of this paper is to verify the hypotheses presented in the literature on the causal relationship between inflation and its uncertainty, for the newest EU countries. To ensure the robustness of the results, in the study four models for inflation uncertainty are estimated in parallel: ARCH (1), GARCH (1,1), EGARCH (1,1,1) and PARCH (1,1,1). The Granger method is used to test the causality between two variables. The working hypothesis is that groups of countries with a similar political and economic background in 1990 and are likely to be characterized by the same causal relationship between inflation and inflation uncertainty. Empirical results partially confirm this hypothesis. C22, E31, E37.

IAE - Inflatable Antenna Experiment

NASA Image and Video Library

1996-06-10

STS077-705-012 (20 May 1996) --- Following its deployment from the Space Shuttle Endeavour, the Inflatable Antenna Experiment (IAE) portion of the Spartan 207 payload is backdropped over Earth as it continues its inflation process. The view was photographed with a handheld 70mm camera during the first full day of orbital operations by the six-member crew. Managed by Goddard Space Flight Center (GSFC), Spartan is designed to provide short-duration, free-flight opportunities for a variety of scientific studies. The Spartan configuration on this flight is unique in that the IAE is part of an additional separate unit which is ejected once the experiment is completed. The IAE experiment will lay the groundwork for future technology development in inflatable space structures, which will be launched and then inflated like a balloon on-orbit.

IAE - Inflatable Antenna Experiment

NASA Image and Video Library

1996-06-10

STS077-705-016 (20 May 1996) --- Following its deployment from the Space Shuttle Endeavour, the Inflatable Antenna Experiment (IAE) part of the Spartan 207 payload nears completion of its inflation process over California?s Pacific Coast near Santa Barbara and Point Conception. The view was photographed with a handheld 70mm camera during the first full day of orbital operations by the six-member crew. Managed by Goddard Space Flight Center (GSFC), Spartan is designed to provide short-duration, free-flight opportunities for a variety of scientific studies. The Spartan configuration on this flight is unique in that the IAE is part of an additional separate unit which is ejected once the experiment is completed. The IAE experiment will lay the groundwork for future technology development in inflatable space structures, which will be launched and then inflated like a balloon on-orbit.

IAE - Inflatable Antenna Experiment

NASA Image and Video Library

1996-05-20

STS077-150-044 (20 May 1996) --- Following its deployment from the Space Shuttle Endeavour, the Spartan 207/Inflatable Antenna Experiment (IAE) payload is backdropped over the Grand Canyon. After the IAE completed its inflation process in free-flight, this view was photographed with a large format still camera. The activity came on the first full day of in-space operations by the six-member crew. Managed by Goddard Space Flight Center (GSFC), Spartan is designed to provide short-duration, free-flight opportunities for a variety of scientific studies. The Spartan configuration on this flight is unique in that the IAE is part of an additional separate unit which is ejected once the experiment is completed. The IAE experiment will lay the groundwork for future technology development in inflatable space structures, which will be launched and then inflated like a balloon on-orbit.

IAE - Inflatable Antenna Experiment

NASA Image and Video Library

1996-06-10

STS077-705-004 (20 May 1996) --- Following its deployment from the Space Shuttle Endeavour, the Inflatable Antenna Experiment (IAE) portion of the Spartan 207 payload begins to inflate, backdropped against clouds over the Pacific Ocean. The view was photographed with a handheld 70mm camera during the first full day of orbital operations by the six-member crew. Managed by Goddard Space Flight Center (GSFC), Spartan is designed to provide short-duration, free-flight opportunities for a variety of scientific studies. The Spartan configuration on this flight is unique in that the IAE is part of an additional separate unit which is ejected once the experiment is completed. The IAE experiment will lay the groundwork for future technology development in inflatable space structures, which will be launched and then inflated like a balloon on-orbit.

IAE - Inflatable Antenna Experiment

NASA Image and Video Library

1996-05-20

STS077-150-022 (20 May 1996) --- After leaving the cargo bay of the Space Shuttle Endeavour, the Spartan 207/Inflatable Antenna Experiment (IAE) payload goes through the final stages its inflation process, backdropped over clouds and blue water. The view was photographed with a large format still camera on the first full day of in-space operations by the six-member crew. Managed by Goddard Space Flight Center (GSFC), Spartan is designed to provide short-duration, free-flight opportunities for a variety of scientific studies. The Spartan configuration on this flight is unique in that the IAE is part of an additional separate unit which is ejected once the experiment is completed. The IAE experiment will lay the groundwork for future technology development in inflatable space structures, which will be launched and then inflated like a balloon on-orbit.

Tribrid Inflation in Supergravity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antusch, Stefan; Dutta, Koushik; Kostka, Philipp M.

2010-02-10

We propose a novel class of F-term hybrid inflation models in supergravity (SUGRA) where the eta-problem is resolved using either a Heisenberg symmetry or a shift symmetry of the Kaehler potential. In addition to the inflaton and the waterfall field, this class (referred to as tribrid inflation) contains a third 'driving' field which contributes the large vacuum energy during inflation by its F-term. In contrast to the 'standard' hybrid scenario, it has several attractive features due to the property of vanishing inflationary superpotential (W{sub inf} = 0) during inflation. While the symmetries of the Kaehler potential ensure a flat inflatonmore » potential at tree-level, quantum corrections induced by symmetry breaking terms in the superpotential generate a slope of the potential and lead to a spectral tilt consistent with recent WMAP observations.« less

Comprehensive characterization and RNA-Seq profiling of the HD-Zip transcription factor family in soybean (Glycine max) during dehydration and salt stress

USDA-ARS?s Scientific Manuscript database

The homeodomain leucine zipper (HD-Zip) transcription factor family is one of the largest plant specific superfamilies, and includes genes with roles in modulation of plant growth and response to environmental stresses. Many HD-Zip genes are well characterized in Arabidopsis (Arabidopsis thaliana), ...

Thermalized axion inflation: Natural and monomial inflation with small r

NASA Astrophysics Data System (ADS)

Ferreira, Ricardo Z.; Notari, Alessio

2018-03-01

A safe way to reheat the Universe, in models of natural and quadratic inflation, is through shift symmetric couplings between the inflaton ϕ and the Standard Model (SM), since they do not generate loop corrections to the potential V (ϕ ). We consider such a coupling to SM gauge fields, of the form ϕ F F ˜/f , with sub-Planckian f . In this case, gauge fields can be exponentially produced already during inflation and thermalize via interactions with charged particles, as pointed out in previous work. This can lead to a plasma of temperature T during inflation, and the thermal masses g T of the gauge bosons can equilibrate the system. In addition, inflaton perturbations δ ϕ can also have a thermal spectrum if they have sufficiently large cross sections with the plasma. In this case, inflationary predictions are strongly modified: (1) scalar perturbations are thermal, and so enhanced over the vacuum, leading to a generic way to suppress the tensor-to-scalar ratio r ; (2) the spectral index is ns-1 =η -4 ɛ . After presenting the relevant conditions for thermalization, we show that thermalized natural and monomial models of inflation agree with present observations and have r ≈10-3-10-2, which is within reach of next generation CMB experiments.

Negative running can prevent eternal inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinney, William H.; Freese, Katherine, E-mail: whkinney@buffalo.edu, E-mail: ktfreese@umich.edu

Current data from the Planck satellite and the BICEP2 telescope favor, at around the 2 σ level, negative running of the spectral index of curvature perturbations from inflation. We show that for negative running α < 0, the curvature perturbation amplitude has a maximum on scales larger than our current horizon size. A condition for the absence of eternal inflation is that the curvature perturbation amplitude always remain below unity on superhorizon scales. For current bounds on n{sub S} from Planck, this corresponds to an upper bound of the running α < −9 × 10{sup −5}, so that even tiny running of the scalar spectral index ismore » sufficient to prevent eternal inflation from occurring, as long as the running remains negative on scales outside the horizon. In single-field inflation models, negative running is associated with a finite duration of inflation: we show that eternal inflation may not occur even in cases where inflation lasts as long as 10{sup 4} e-folds.« less

Primordial anisotropies in gauged hybrid inflation

NASA Astrophysics Data System (ADS)

Akbar Abolhasani, Ali; Emami, Razieh; Firouzjahi, Hassan

2014-05-01

We study primordial anisotropies generated in the model of gauged hybrid inflation in which the complex waterfall field is charged under a U(1)gauge field. Primordial anisotropies are generated either actively during inflation or from inhomogeneities modulating the surface of end of inflation during waterfall transition. We present a consistent δN mechanism to calculate the anisotropic power spectrum and bispectrum. We show that the primordial anisotropies generated at the surface of end of inflation do not depend on the number of e-folds and therefore do not produce dangerously large anisotropies associated with the IR modes. Furthermore, one can find the parameter space that the anisotropies generated from the surface of end of inflation cancel the anisotropies generated during inflation, therefore relaxing the constrains on model parameters imposed from IR anisotropies. We also show that the gauge field fluctuations induce a red-tilted power spectrum so the averaged power spectrum from the gauge field can change the total power spectrum from blue to red. Therefore, hybrid inflation, once gauged under a U(1) field, can be consistent with the cosmological observations.

Nonthermal gravitino production in tribrid inflation

NASA Astrophysics Data System (ADS)

Antusch, Stefan; Dutta, Koushik

2015-10-01

We investigate nonthermal gravitino production after tribrid inflation in supergravity, which is a variant of supersymmetric hybrid inflation where three fields are involved in the inflationary model and where the inflaton field resides in the matter sector of the theory. In contrast to conventional supersymmetric hybrid inflation, where nonthermal gravitino production imposes severe constraints on the inflationary model, we find that the "nonthermal gravitino problem" is generically absent in models of tribrid inflation, mainly due to two effects: (i) With the inflaton in tribrid inflation (after inflation) being lighter than the waterfall field, the latter has a second decay channel with a much larger rate than for the decay into gravitinos. This reduces the branching ratio for the decay of the waterfall field into gravitinos. (ii) The inflaton generically decays later than the waterfall field, and it does not produce gravitinos when it decays. This leads to a dilution of the gravitino population from the decays of the waterfall field. The combination of both effects generically leads to a strongly reduced gravitino production in tribrid inflation.

Structurally efficient inflatable protective device

DOEpatents

Nelsen, James M.; Whinery, Larry D.; Gwinn, Kenneth W.; McBride, Donald D.; Luna, Daniel A.; Holder, Joseph P.; Bliton, Richard J.

1997-01-01

An apparatus and method for making a low cost, self-venting, inflatable protective cushion of simple and structurally efficient design with a shape and construction that optimizes the cushion's ability to withstand inflation pressures and impact when deployed which includes a sheet defined by at least one fold line and a plurality of flap portions, each flap portion having a base edge corresponding to a fold line and at least two side edges each extending outwardly from a base edge and ultimately converging to meet each other, the flap portions being folded at the fold line(s) and being joined at corresponding side edges to define an inflatable chamber. The inflatable protective cushion and method for making same may further include a lightweight, low permeability, fabric that optimizes the cushion's ability to withstand inflation pressures and impact when deployed and minimizes the packed volume of the cushion when stored.

Structurally efficient inflatable protective device

DOEpatents

Nelsen, James M.; Whinery, Larry D.; Gwinn, Kenneth W.; McBride, Donald D.; Luna, Daniel A.; Holder, Joseph P.; Bliton, Richard J.

1996-01-01

An apparatus and method for making a low cost, self-venting, inflatable protective cushion of simple and structurally efficient design with a shape and construction that optimizes the cushion's ability to withstand inflation pressures and impact when deployed which includes a sheet defined by at least one fold line and a plurality of flap portions, each flap portion having a base edge corresponding to a fold line and at least two side edges each extending outwardly from a base edge and ultimately converging to meet each other, the flap portions being folded at the fold line(s) and being Joined at corresponding side edges to define an inflatable chamber. The inflatable protective cushion and method for making same may further include a lightweight, low permeability, fabric that optimizes the cushion's ability to withstand inflation pressures and impact when deployed and minimizes the packed volume of the cushion when stored.

Structurally efficient inflatable protective device

DOEpatents

Nelsen, James M.; Whinery, Larry D.; Gwinn, Kenneth W.; McBride, Donald D.; Luna, Daniel A.; Holder, Joseph P.; Bliton, Richard J.

1996-01-01

An apparatus and method for making a low cost, self-venting, inflatable protective cushion of simple and structurally efficient design with a shape and construction that optimizes the cushion's ability to withstand inflation pressures and impact when deployed which includes a sheet defined by at least one fold line and a plurality of flap portions, each flap portion having a base edge corresponding to a fold line and at least two side edges each extending outwardly from a base edge and ultimately converging to meet each other, the flap portions being folded at the fold line(s) and being joined at corresponding side edges to define an inflatable chamber. The inflatable protective cushion and method for making same may further include a lightweight, low permeability, fabric that optimizes the cushion's ability to withstand inflation pressures and impact when deployed and minimizes the packed volume of the cushion when stored.

Modular invariant inflation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobayashi, Tatsuo; Nitta, Daisuke; Urakawa, Yuko

2016-08-08

Modular invariance is a striking symmetry in string theory, which may keep stringy corrections under control. In this paper, we investigate a phenomenological consequence of the modular invariance, assuming that this symmetry is preserved as well as in a four dimensional (4D) low energy effective field theory. As a concrete setup, we consider a modulus field T whose contribution in the 4D effective field theory remains invariant under the modular transformation and study inflation drived by T. The modular invariance restricts a possible form of the scalar potenntial. As a result, large field models of inflation are hardly realized. Meanwhile,more » a small field model of inflation can be still accomodated in this restricted setup. The scalar potential traced during the slow-roll inflation mimics the hilltop potential V{sub ht}, but it also has a non-negligible deviation from V{sub ht}. Detecting the primordial gravitational waves predicted in this model is rather challenging. Yet, we argue that it may be still possible to falsify this model by combining the information in the reheating process which can be determined self-completely in this setup.« less

Inflatable antennas for microwave pwoer transmission

NASA Technical Reports Server (NTRS)

Williams, Geoff

1989-01-01

Operational phase of the inflatable radiator; inflatable space structures; advantages; inflated thin-film satellites; antenna configuration; 3 meter diameter test paraboloid (HAIR program); and weight breakdown for the 100 meter diameter reflector are outlined. This presentation is represented by viewgraphs only.

Oscillatory Reduction in Option Pricing Formula Using Shifted Poisson and Linear Approximation

NASA Astrophysics Data System (ADS)

Nur Rachmawati, Ro'fah; Irene; Budiharto, Widodo

2014-03-01

Option is one of derivative instruments that can help investors improve their expected return and minimize the risks. However, the Black-Scholes formula is generally used in determining the price of the option does not involve skewness factor and it is difficult to apply in computing process because it produces oscillation for the skewness values close to zero. In this paper, we construct option pricing formula that involve skewness by modified Black-Scholes formula using Shifted Poisson model and transformed it into the form of a Linear Approximation in the complete market to reduce the oscillation. The results are Linear Approximation formula can predict the price of an option with very accurate and successfully reduce the oscillations in the calculation processes.

46 CFR 169.849 - Posting placards containing instructions for launching and inflating inflatable liferafts.

Code of Federal Regulations, 2012 CFR

2012-10-01

... accessible to the ship's company and guests approved placards containing instructions for launching and inflating inflatable liferafts. The number and location of such placards for a particular vessel shall be...

46 CFR 169.849 - Posting placards containing instructions for launching and inflating inflatable liferafts.

Code of Federal Regulations, 2014 CFR

2014-10-01

... accessible to the ship's company and guests approved placards containing instructions for launching and inflating inflatable liferafts. The number and location of such placards for a particular vessel shall be...

46 CFR 169.849 - Posting placards containing instructions for launching and inflating inflatable liferafts.

Code of Federal Regulations, 2011 CFR

2011-10-01

... accessible to the ship's company and guests approved placards containing instructions for launching and inflating inflatable liferafts. The number and location of such placards for a particular vessel shall be...

46 CFR 169.849 - Posting placards containing instructions for launching and inflating inflatable liferafts.

Code of Federal Regulations, 2013 CFR

2013-10-01

... accessible to the ship's company and guests approved placards containing instructions for launching and inflating inflatable liferafts. The number and location of such placards for a particular vessel shall be...

The Relationship between Inflation and Inflation Uncertainty. Empirical Evidence for the Newest EU Countries

PubMed Central

Viorica, Daniela; Jemna, Danut; Pintilescu, Carmen; Asandului, Mircea

2014-01-01

The objective of this paper is to verify the hypotheses presented in the literature on the causal relationship between inflation and its uncertainty, for the newest EU countries. To ensure the robustness of the results, in the study four models for inflation uncertainty are estimated in parallel: ARCH (1), GARCH (1,1), EGARCH (1,1,1) and PARCH (1,1,1). The Granger method is used to test the causality between two variables. The working hypothesis is that groups of countries with a similar political and economic background in 1990 and are likely to be characterized by the same causal relationship between inflation and inflation uncertainty. Empirical results partially confirm this hypothesis. Jel Classification C22, E31, E37. PMID:24633073

Structurally efficient inflatable protective device

DOEpatents

Nelsen, J.M.; Whinery, L.D.; Gwinn, K.W.; McBride, D.D.; Luna, D.A.; Holder, J.P.; Bliton, R.J.

1997-03-04

An apparatus and method are disclosed for making a low cost, self-venting, inflatable protective cushion of simple and structurally efficient design with a shape and construction that optimizes the cushion`s ability to withstand inflation pressures and impact when deployed which includes a sheet defined by at least one fold line and a plurality of flap portions, each flap portion having a base edge corresponding to a fold line and at least two side edges each extending outwardly from a base edge and ultimately converging to meet each other, the flap portions being folded at the fold line(s) and being joined at corresponding side edges to define an inflatable chamber. The inflatable protective cushion and method for making same may further include a lightweight, low permeability, fabric that optimizes the cushion`s ability to withstand inflation pressures and impact when deployed and minimizes the packed volume of the cushion when stored. 22 figs.

Structurally efficient inflatable protective device

DOEpatents

Nelsen, J.M.; Whinery, L.D.; Gwinn, K.W.; McBride, D.D.; Luna, D.A.; Holder, J.P.; Bliton, R.J.

1996-01-09

An apparatus and method are disclosed for making a low cost, self-venting, inflatable protective cushion of simple and structurally efficient design with a shape and construction that optimizes the cushion`s ability to withstand inflation pressures and impact when deployed which includes a sheet defined by at least one fold line and a plurality of flap portions, each flap portion having a base edge corresponding to a fold line and at least two side edges each extending outwardly from a base edge and ultimately converging to meet each other, the flap portions being folded at the fold line(s) and being joined at corresponding side edges to define an inflatable chamber. The inflatable protective cushion and method for making same may further include a lightweight, low permeability, fabric that optimizes the cushion`s ability to withstand inflation pressures and impact when deployed and minimizes the packed volume of the cushion when stored. 22 figs.

Sustained inflation during neonatal resuscitation.

PubMed

Keszler, Martin

2015-04-01

Sustained inflation performed shortly after birth to help clear lung fluid and establish functional residual capacity in preterm infants is gaining popularity, but definitive evidence for its effectiveness is lacking. Although there is a sound physiologic basis for this approach, and much preclinical experimental evidence of effectiveness, the results of recent animal studies and clinical trials have been inconsistent. The most recent data from a multicenter randomized trial suggest a modest benefit of sustained inflation in reducing the need for mechanical ventilation in extremely-low-birth-weight infants. However, the impact may be more modest than earlier retrospective cohort comparisons suggested. The trend toward more airleak and a higher rate of intraventricular hemorrhage is worrisome. Sustained inflation may be ineffective unless some spontaneous respiratory effort is present. Several on-going trials should further clarify the putative benefits of sustained inflation. Delivery room sustained inflation is an attractive concept that holds much promise, but widespread clinical application should await definitive evidence from on-going clinical trials.

Goldstone inflation

NASA Astrophysics Data System (ADS)

Croon, Djuna; Sanz, Verónica; Setford, Jack

2015-10-01

Identifying the inflaton with a pseudo-Goldstone boson explains the flatness of its potential. Successful Goldstone Inflation should also be robust against UV corrections, such as from quantum gravity: in the language of the effective field theory this implies that all scales are sub-Planckian. In this paper we present scenarios which realise both requirements by examining the structure of Goldstone potentials arising from Coleman-Weinberg contributions. We focus on single-field models, for which we notice that both bosonic and fermionic contributions are required and that spinorial fermion representations can generate the right potential shape. We then evaluate the constraints on non-Gaussianity from higher-derivative interactions, finding that axiomatic constraints on Goldstone boson scattering prevail over the current CMB measurements. The fit to CMB data can be connected to the UV completions for Goldstone Inflation, finding relations in the spectrum of new resonances. Finally, we show how hybrid inflation can be realised in the same context, where both the inflaton and the waterfall fields share a common origin as Goldstones.

Inflation from extra dimensions

NASA Astrophysics Data System (ADS)

Levin, Janna J.

1995-02-01

A gravity-driven inflation is shown to arise from a simple higher-dimensional universe. In vacuum, the shear of n > 1 contracting dimensions is able to inflate the remaining three spatial dimensions. Said another way, the expansion of the 3-volume is accelerated by the contraction of the n-volume. Upon dimensional reduction, the theory is equivalent to a four-dimensional cosmology with a dynamical Planck mass. A connection can therefore be made to recent examples of inflation powered by a dilaton kinetic energy. Unfortunately, the graceful exit problem encountered in dilaton cosmologies will haunt this cosmology as well.

Plausible double inflation

NASA Technical Reports Server (NTRS)

Holman, Richard; Kolb, Edward W.; Vadas, Sharon L.; Wang, Yun

1991-01-01

It is likely that extended inflation is followed by an epoch of slowroll inflation. Such a sequence of events may lead to a very interesting perturbation spectrum with significant power on the scale of the transition between the extended and slowroll phase, superimposed upon a power-law spectrum with deviations from the Harrison-Zeldovich slope. Normalization of the spectra above and below the transition scale is expected to differ.

Accidental inflation from Kähler uplifting

NASA Astrophysics Data System (ADS)

Ben-Dayan, Ido; Jing, Shenglin; Westphal, Alexander; Wieck, Clemens

2014-03-01

We analyze the possibility of realizing inflation with a subsequent dS vacuum in the Käahler uplifting scenario. The inclusion of several quantum corrections to the 4d effective action evades previous no-go theorems and allows for construction of simple and successful models of string inflation. The predictions of several benchmark models are in accord with current observations, i.e., a red spectral index, negligible non-gaussianity, and spectral distortions similar to the simplest models of inflation. A particularly interesting subclass of models are ``left-rolling" ones, where the overall volume of the compactified dimensions shrinks during inflation. We call this phenomenon ``inflation by deflation" (IBD), where deflation refers to the internal manifold. This subclass has the appealing features of being insensitive to initial conditions, avoiding the overshooting problem, and allowing for observable running α ~ 0.012 and enhanced tensor-to-scalar ratio r ~ 10-5. The latter results differ significantly from many string inflation models.

Mass inflation followed by Belinskii-Khalatnikov-Lifshitz collapse inside accreting, rotating black holes

NASA Astrophysics Data System (ADS)

Hamilton, Andrew J. S.

2017-10-01

Numerical evidence is presented that the Poisson-Israel mass inflation instability at the inner horizon of an accreting, rotating black hole is generically followed by Belinskii-Khalatnikov-Lifshitz oscillatory collapse to a spacelike singularity. The computation involves following all 6 degrees of freedom of the gravitational field. To simplify the problem, the computation takes as initial conditions the conformally separable solutions of Andrew J. S. Hamilton and Gavin Polhemus [Interior structure of rotating black holes. I. Concise derivation, Phys. Rev. D 84, 124055 (2011), 10.1103/PhysRevD.84.124055] and Andrew J. S. Hamilton [Interior structure of rotating black holes. II. Uncharged black holes, Phys. Rev. D 84, 124056 (2011), 10.1103/PhysRevD.84.124056] just above the inner horizon of a slowly accreting, rotating black hole and integrates the equations inward along single latitudes.

Individual- and community-level correlates of cigarette-smoking trajectories from age 13 to 32 in a U.S. population-based sample.

PubMed

Fuemmeler, Bernard; Lee, Chien-Ti; Ranby, Krista W; Clark, Trenette; McClernon, F Joseph; Yang, Chongming; Kollins, Scott H

2013-09-01

Characterizing smoking behavior is important for informing etiologic models and targeting prevention efforts. This study explored the effects of both individual- and community-level variables in predicting cigarette use vs. non-use and level of use among adolescents as they transition into adulthood. Data on 14,779 youths (53% female) were drawn from the National Longitudinal Study of Adolescent Health (Add Health); a nationally representative longitudinal cohort. A cohort sequential design allowed for examining trajectories of smoking typologies from age 13 to 32 years. Smoking trajectories were evaluated by using a zero-inflated Poisson (ZIP) latent growth analysis and latent class growth analysis modeling approach. Significant relationships emerged between both individual- and community-level variables and smoking outcomes. Maternal and peer smoking predicted increases in smoking over development and were associated with a greater likelihood of belonging to any of the four identified smoking groups versus Non-Users. Conduct problems and depressive symptoms during adolescence were related to cigarette use versus non-use. State-level prevalence of adolescent smoking was related to greater cigarette use during adolescence. Individual- and community-level variables that distinguish smoking patterns within the population aid in understanding cigarette use versus non-use and the quantity of cigarette use into adulthood. Our findings suggest that efforts to prevent cigarette use would benefit from attention to both parental and peer smoking and individual well-being. Future work is needed to better understand the role of variables in the context of multiple levels (individual and community-level) on smoking trajectories. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The relationship between gambling attitudes, involvement, and problems in adolescence: Examining the moderating role of coping strategies and parenting styles.

PubMed

Dixon, Ramsay W; Youssef, George J; Hasking, Penelope; Yücel, Murat; Jackson, Alun C; Dowling, Nicki A

2016-07-01

Several factors are associated with an increased risk of adolescent problem gambling, including positive gambling attitudes, higher levels of gambling involvement, ineffective coping strategies and unhelpful parenting practices. It is less clear, however, how these factors interact or influence each other in the development of problem gambling behavior during adolescence. The aim of the current study was to simultaneously explore these predictors, with a particular focus on the extent to which coping skills and parenting styles may moderate the expected association between gambling involvement and gambling problems. Participants were 612 high school students. The data were analyzed using a zero-inflated Poisson (ZIP) regression model, controlling for gender. Although several variables predicted the number of symptoms associated with problem gambling, none of them predicted the probability of displaying any problem gambling. Gambling involvement fully mediated the relationship between positive gambling attitudes and gambling problem severity. There was a significant relationship between gambling involvement and problems at any level of problem focused coping, reference to others and inconsistent discipline. However, adaptive coping styles employed by adolescents and consistent disciplinary practices by parents were buffers of gambling problems at low levels of adolescent gambling involvement, but failed to protect adolescents when their gambling involvement was high. These findings indicate that research exploring the development of gambling problems is required and imply that coping and parenting interventions may have particular utility for adolescents who are at risk of development gambling problems but who are not gambling frequently. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bispectrum from open inflation

NASA Astrophysics Data System (ADS)

Sugimura, Kazuyuki; Komatsu, Eiichiro

2013-11-01

We calculate the bispectrum of primordial curvature perturbations, ζ, generated during ``open inflation.'' Inflation occurs inside a bubble nucleated via quantum tunneling from the background false vacuum state. Our universe lives inside the bubble, which can be described as a Friedmann-Lemaȋtre-Robertson-Walker (FLRW) universe with negative spatial curvature, undergoing slow-roll inflation. We pay special attention to the issue of an initial state for quantum fluctuations. A ``vacuum state'' defined by a positive-frequency mode in de Sitter space charted by open coordinates is different from the Euclidean vacuum (which is equivalent to the so-called ``Bunch-Davies vacuum'' defined by a positive-frequency mode in de Sitter space charted by flat coordinates). Quantum tunneling (bubble nucleation) then modifies the initial state away from the original Euclidean vacuum. While most of the previous study on modifications of the initial quantum state introduces, by hand, an initial time at which the quantum state is modified as well as the form of the modification, an effective initial time naturally emerges and the form is fixed by quantum tunneling in open inflation models. Therefore, open inflation enables a self-consistent computation of the effect of a modified initial state on the bispectrum. We find a term which goes as langleζk1ζk2ζk3ranglepropto1/k12k34 in the so-called squeezed configurations, k3 << k1 ≈ k2, in agreement with the previous study on modifications of the initial state. The bispectrum in the exact folded limit, e.g., k1 = k2+k3, is also enhanced and remains finite. However, these terms are exponentially suppressed when the wavelength of ζ is smaller than the curvature radius of the universe. The leading-order bispectrum is equal to the usual one from single-field slow-roll inflation; the terms specific for open inflation arise only in the sub-leading order when the wavelength of ζ is smaller than the curvature radius.

Interleukin-1beta contributes via nitric oxide to the upregulation and functional activity of the zinc transporter Zip14 (Slc39a14) in murine hepatocytes.

PubMed

Lichten, Louis A; Liuzzi, Juan P; Cousins, Robert J

2009-04-01

Zinc metabolism during chronic disease is dysregulated by inflammatory cytokines. Experiments with IL-6 knockout mice show that LPS regulates expression of the zinc transporter, Zip14, by a mechanism that is partially independent of IL-6. The LPS-induced model of sepsis may occur by a mechanism signaled by nitric oxide (NO) as a secondary messenger. To address the hypothesis that NO can modulate Zip14 expression, we treated primary hepatocytes from wild-type mice with the NO donor S-nitroso N-acetyl penicillamine (SNAP). After treatment with SNAP, steady-state Zip14 mRNA levels displayed a maximal increase after 8 h and a concomitant increase in the transcriptional activity of the gene. Chromatin immunoprecipitation documented the kinetics of activator protein (AP)-1 and RNA polymerase II association with the Zip14 promoter after NO exposure, indicating a role of AP-1 in transcription of Zip14. We then stimulated the primary murine hepatocytes with IL-1beta, an LPS-induced proinflammatory cytokine and a potent activator of inducible NO synthase (iNOS) and NO production. In support of our hypothesis, IL-1beta treatment led to a threefold increase in Zip14 mRNA and enhanced zinc transport, as measured with a zinc fluorophore, in wild-type but not iNOS-/- hepatocytes. These data suggest that signaling pathways activated by NO are factors in the upregulation of Zip14, which in turn mediates hepatic zinc accumulation and hypozincemia during inflammation and sepsis.

Gauge fields and inflation

NASA Astrophysics Data System (ADS)

Maleknejad, A.; Sheikh-Jabbari, M. M.; Soda, J.

2013-07-01

The isotropy and homogeneity of the cosmic microwave background (CMB) favors “scalar driven” early Universe inflationary models. However, gauge fields and other non-scalar fields are far more common at all energy scales, in particular at high energies seemingly relevant to inflation models. Hence, in this review we consider the role and consequences, theoretical and observational, that gauge fields can have during the inflationary era. Gauge fields may be turned on in the background during inflation, or may become relevant at the level of cosmic perturbations. There have been two main classes of models with gauge fields in the background, models which show violation of the cosmic no-hair theorem and those which lead to isotropic FLRW cosmology, respecting the cosmic no-hair theorem. Models in which gauge fields are only turned on at the cosmic perturbation level, may source primordial magnetic fields. We also review specific observational features of these models on the CMB and/or the primordial cosmic magnetic fields. Our discussions will be mainly focused on the inflation period, with only a brief discussion on the post inflationary (p)reheating era. Large field models: The initial value of the inflaton field is large, generically super-Planckian, and it rolls slowly down toward the potential minimum at smaller φ values. For instance, chaotic inflation is one of the representative models of this class. The typical potential of large-field models has a monomial form as V(φ)=V0φn. A simple analysis using the dynamical equations reveals that for number of e-folds Ne larger than 60, we require super-Planckian initial field values,5φ0>3M. For these models typically ɛ˜η˜Ne-1. Small field models: Inflaton field is initially small and slowly evolves toward the potential minimum at larger φ values. The small field models are characterized by the following potential V(φ)=V0(1-(), which corresponds to a Taylor expansion about the origin, but more realistic

46 CFR 169.849 - Posting placards containing instructions for launching and inflating inflatable liferafts.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Inspections § 169.849 Posting placards containing instructions for launching and inflating inflatable... accessible to the ship's company and guests approved placards containing instructions for launching and... determined by the Officer in Charge, Marine Inspection. ...

Sparse Poisson noisy image deblurring.

PubMed

Carlavan, Mikael; Blanc-Féraud, Laure

2012-04-01

Deblurring noisy Poisson images has recently been a subject of an increasing amount of works in many areas such as astronomy and biological imaging. In this paper, we focus on confocal microscopy, which is a very popular technique for 3-D imaging of biological living specimens that gives images with a very good resolution (several hundreds of nanometers), although degraded by both blur and Poisson noise. Deconvolution methods have been proposed to reduce these degradations, and in this paper, we focus on techniques that promote the introduction of an explicit prior on the solution. One difficulty of these techniques is to set the value of the parameter, which weights the tradeoff between the data term and the regularizing term. Only few works have been devoted to the research of an automatic selection of this regularizing parameter when considering Poisson noise; therefore, it is often set manually such that it gives the best visual results. We present here two recent methods to estimate this regularizing parameter, and we first propose an improvement of these estimators, which takes advantage of confocal images. Following these estimators, we secondly propose to express the problem of the deconvolution of Poisson noisy images as the minimization of a new constrained problem. The proposed constrained formulation is well suited to this application domain since it is directly expressed using the antilog likelihood of the Poisson distribution and therefore does not require any approximation. We show how to solve the unconstrained and constrained problems using the recent alternating-direction technique, and we present results on synthetic and real data using well-known priors, such as total variation and wavelet transforms. Among these wavelet transforms, we specially focus on the dual-tree complex wavelet transform and on the dictionary composed of curvelets and an undecimated wavelet transform.

Poly-symplectic Groupoids and Poly-Poisson Structures

NASA Astrophysics Data System (ADS)

Martinez, Nicolas

2015-05-01

We introduce poly-symplectic groupoids, which are natural extensions of symplectic groupoids to the context of poly-symplectic geometry, and define poly-Poisson structures as their infinitesimal counterparts. We present equivalent descriptions of poly-Poisson structures, including one related with AV-Dirac structures. We also discuss symmetries and reduction in the setting of poly-symplectic groupoids and poly-Poisson structures, and use our viewpoint to revisit results and develop new aspects of the theory initiated in Iglesias et al. (Lett Math Phys 103:1103-1133, 2013).

12 CFR 1780.80 - Inflation adjustments.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Inflation adjustments. 1780.80 Section 1780.80... DEVELOPMENT RULES OF PRACTICE AND PROCEDURE RULES OF PRACTICE AND PROCEDURE Civil Money Penalty Inflation Adjustments § 1780.80 Inflation adjustments. The maximum amount of each civil money penalty within OFHEO's...

Comments on SUSY Inflation Models on the Brane