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The limiting distribution of the Gibbs sampler for the intrinsic conditional autoregressive model

Marco A. R. Ferreira.

Source: Brazilian Journal of Probability and Statistics, Volume 33, Number 4, 734--744.

Abstract:
We study the limiting behavior of the one-at-a-time Gibbs sampler for the intrinsic conditional autoregressive model with centering on the fly. The intrinsic conditional autoregressive model is widely used as a prior for random effects in hierarchical models for spatial modeling. This model is defined by full conditional distributions that imply an improper joint “density” with a multivariate Gaussian kernel and a singular precision matrix. To guarantee propriety of the posterior distribution, usually at the end of each iteration of the Gibbs sampler the random effects are centered to sum to zero in what is widely known as centering on the fly. While this works well in practice, this informal computational way to recenter the random effects obscures their implied prior distribution and prevents the development of formal Bayesian procedures. Here we show that the implied prior distribution, that is, the limiting distribution of the one-at-a-time Gibbs sampler for the intrinsic conditional autoregressive model with centering on the fly is a singular Gaussian distribution with a covariance matrix that is the Moore–Penrose inverse of the precision matrix. This result has important implications for the development of formal Bayesian procedures such as reference priors and Bayes-factor-based model selection for spatial models.




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Failure rate of Birnbaum–Saunders distributions: Shape, change-point, estimation and robustness

Emilia Athayde, Assis Azevedo, Michelli Barros, Víctor Leiva.

Source: Brazilian Journal of Probability and Statistics, Volume 33, Number 2, 301--328.

Abstract:
The Birnbaum–Saunders (BS) distribution has been largely studied and applied. A random variable with BS distribution is a transformation of another random variable with standard normal distribution. Generalized BS distributions are obtained when the normally distributed random variable is replaced by another symmetrically distributed random variable. This allows us to obtain a wide class of positively skewed models with lighter and heavier tails than the BS model. Its failure rate admits several shapes, including the unimodal case, with its change-point being able to be used for different purposes. For example, to establish the reduction in a dose, and then in the cost of the medical treatment. We analyze the failure rates of generalized BS distributions obtained by the logistic, normal and Student-t distributions, considering their shape and change-point, estimating them, evaluating their robustness, assessing their performance by simulations, and applying the results to real data from different areas.




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A bimodal gamma distribution: Properties, regression model and applications. (arXiv:2004.12491v2 [stat.ME] UPDATED)

In this paper we propose a bimodal gamma distribution using a quadratic transformation based on the alpha-skew-normal model. We discuss several properties of this distribution such as mean, variance, moments, hazard rate and entropy measures. Further, we propose a new regression model with censored data based on the bimodal gamma distribution. This regression model can be very useful to the analysis of real data and could give more realistic fits than other special regression models. Monte Carlo simulations were performed to check the bias in the maximum likelihood estimation. The proposed models are applied to two real data sets found in literature.




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A Distributionally Robust Area Under Curve Maximization Model. (arXiv:2002.07345v2 [math.OC] UPDATED)

Area under ROC curve (AUC) is a widely used performance measure for classification models. We propose two new distributionally robust AUC maximization models (DR-AUC) that rely on the Kantorovich metric and approximate the AUC with the hinge loss function. We consider the two cases with respectively fixed and variable support for the worst-case distribution. We use duality theory to reformulate the DR-AUC models and derive tractable convex optimization problems. The numerical experiments show that the proposed DR-AUC models -- benchmarked with the standard deterministic AUC and the support vector machine models - perform better in general and in particular improve the worst-case out-of-sample performance over the majority of the considered datasets, thereby showing their robustness. The results are particularly encouraging since our numerical experiments are conducted with training sets of small size which have been known to be conducive to low out-of-sample performance.




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Restricting the Flow: Information Bottlenecks for Attribution. (arXiv:2001.00396v3 [stat.ML] UPDATED)

Attribution methods provide insights into the decision-making of machine learning models like artificial neural networks. For a given input sample, they assign a relevance score to each individual input variable, such as the pixels of an image. In this work we adapt the information bottleneck concept for attribution. By adding noise to intermediate feature maps we restrict the flow of information and can quantify (in bits) how much information image regions provide. We compare our method against ten baselines using three different metrics on VGG-16 and ResNet-50, and find that our methods outperform all baselines in five out of six settings. The method's information-theoretic foundation provides an absolute frame of reference for attribution values (bits) and a guarantee that regions scored close to zero are not necessary for the network's decision. For reviews: https://openreview.net/forum?id=S1xWh1rYwB For code: https://github.com/BioroboticsLab/IBA




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An n-dimensional Rosenbrock Distribution for MCMC Testing. (arXiv:1903.09556v4 [stat.CO] UPDATED)

The Rosenbrock function is an ubiquitous benchmark problem for numerical optimisation, and variants have been proposed to test the performance of Markov Chain Monte Carlo algorithms. In this work we discuss the two-dimensional Rosenbrock density, its current $n$-dimensional extensions, and their advantages and limitations. We then propose a new extension to arbitrary dimensions called the Hybrid Rosenbrock distribution, which is composed of conditional normal kernels arranged in such a way that preserves the key features of the original kernel. Moreover, due to its structure, the Hybrid Rosenbrock distribution is analytically tractable and possesses several desirable properties, which make it an excellent test model for computational algorithms.




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Distributional Robustness of K-class Estimators and the PULSE. (arXiv:2005.03353v1 [econ.EM])

In causal settings, such as instrumental variable settings, it is well known that estimators based on ordinary least squares (OLS) can yield biased and non-consistent estimates of the causal parameters. This is partially overcome by two-stage least squares (TSLS) estimators. These are, under weak assumptions, consistent but do not have desirable finite sample properties: in many models, for example, they do not have finite moments. The set of K-class estimators can be seen as a non-linear interpolation between OLS and TSLS and are known to have improved finite sample properties. Recently, in causal discovery, invariance properties such as the moment criterion which TSLS estimators leverage have been exploited for causal structure learning: e.g., in cases, where the causal parameter is not identifiable, some structure of the non-zero components may be identified, and coverage guarantees are available. Subsequently, anchor regression has been proposed to trade-off invariance and predictability. The resulting estimator is shown to have optimal predictive performance under bounded shift interventions. In this paper, we show that the concepts of anchor regression and K-class estimators are closely related. Establishing this connection comes with two benefits: (1) It enables us to prove robustness properties for existing K-class estimators when considering distributional shifts. And, (2), we propose a novel estimator in instrumental variable settings by minimizing the mean squared prediction error subject to the constraint that the estimator lies in an asymptotically valid confidence region of the causal parameter. We call this estimator PULSE (p-uncorrelated least squares estimator) and show that it can be computed efficiently, even though the underlying optimization problem is non-convex. We further prove that it is consistent.




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Fast multivariate empirical cumulative distribution function with connection to kernel density estimation. (arXiv:2005.03246v1 [cs.DS])

This paper revisits the problem of computing empirical cumulative distribution functions (ECDF) efficiently on large, multivariate datasets. Computing an ECDF at one evaluation point requires $mathcal{O}(N)$ operations on a dataset composed of $N$ data points. Therefore, a direct evaluation of ECDFs at $N$ evaluation points requires a quadratic $mathcal{O}(N^2)$ operations, which is prohibitive for large-scale problems. Two fast and exact methods are proposed and compared. The first one is based on fast summation in lexicographical order, with a $mathcal{O}(N{log}N)$ complexity and requires the evaluation points to lie on a regular grid. The second one is based on the divide-and-conquer principle, with a $mathcal{O}(Nlog(N)^{(d-1){vee}1})$ complexity and requires the evaluation points to coincide with the input points. The two fast algorithms are described and detailed in the general $d$-dimensional case, and numerical experiments validate their speed and accuracy. Secondly, the paper establishes a direct connection between cumulative distribution functions and kernel density estimation (KDE) for a large class of kernels. This connection paves the way for fast exact algorithms for multivariate kernel density estimation and kernel regression. Numerical tests with the Laplacian kernel validate the speed and accuracy of the proposed algorithms. A broad range of large-scale multivariate density estimation, cumulative distribution estimation, survival function estimation and regression problems can benefit from the proposed numerical methods.




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Terrestrial hermit crab populations in the Maldives : ecology, distribution and anthropogenic impact

Steibl, Sebastian, author
9783658295417 (electronic bk.)




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Handbook of optimization in electric power distribution systems

9783030361150




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100 cases in clinical pharmacology, therapeutics and prescribing

Layne, Kerry, author.
9780429624537 electronic book




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Distributed estimation of principal eigenspaces

Jianqing Fan, Dong Wang, Kaizheng Wang, Ziwei Zhu.

Source: The Annals of Statistics, Volume 47, Number 6, 3009--3031.

Abstract:
Principal component analysis (PCA) is fundamental to statistical machine learning. It extracts latent principal factors that contribute to the most variation of the data. When data are stored across multiple machines, however, communication cost can prohibit the computation of PCA in a central location and distributed algorithms for PCA are thus needed. This paper proposes and studies a distributed PCA algorithm: each node machine computes the top $K$ eigenvectors and transmits them to the central server; the central server then aggregates the information from all the node machines and conducts a PCA based on the aggregated information. We investigate the bias and variance for the resulting distributed estimator of the top $K$ eigenvectors. In particular, we show that for distributions with symmetric innovation, the empirical top eigenspaces are unbiased, and hence the distributed PCA is “unbiased.” We derive the rate of convergence for distributed PCA estimators, which depends explicitly on the effective rank of covariance, eigengap, and the number of machines. We show that when the number of machines is not unreasonably large, the distributed PCA performs as well as the whole sample PCA, even without full access of whole data. The theoretical results are verified by an extensive simulation study. We also extend our analysis to the heterogeneous case where the population covariance matrices are different across local machines but share similar top eigenstructures.




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Eigenvalue distributions of variance components estimators in high-dimensional random effects models

Zhou Fan, Iain M. Johnstone.

Source: The Annals of Statistics, Volume 47, Number 5, 2855--2886.

Abstract:
We study the spectra of MANOVA estimators for variance component covariance matrices in multivariate random effects models. When the dimensionality of the observations is large and comparable to the number of realizations of each random effect, we show that the empirical spectra of such estimators are well approximated by deterministic laws. The Stieltjes transforms of these laws are characterized by systems of fixed-point equations, which are numerically solvable by a simple iterative procedure. Our proof uses operator-valued free probability theory, and we establish a general asymptotic freeness result for families of rectangular orthogonally invariant random matrices, which is of independent interest. Our work is motivated in part by the estimation of components of covariance between multiple phenotypic traits in quantitative genetics, and we specialize our results to common experimental designs that arise in this application.




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Estimating and forecasting the smoking-attributable mortality fraction for both genders jointly in over 60 countries

Yicheng Li, Adrian E. Raftery.

Source: The Annals of Applied Statistics, Volume 14, Number 1, 381--408.

Abstract:
Smoking is one of the leading preventable threats to human health and a major risk factor for lung cancer, upper aerodigestive cancer and chronic obstructive pulmonary disease. Estimating and forecasting the smoking attributable fraction (SAF) of mortality can yield insights into smoking epidemics and also provide a basis for more accurate mortality and life expectancy projection. Peto et al. ( Lancet 339 (1992) 1268–1278) proposed a method to estimate the SAF using the lung cancer mortality rate as an indicator of exposure to smoking in the population of interest. Here, we use the same method to estimate the all-age SAF (ASAF) for both genders for over 60 countries. We document a strong and cross-nationally consistent pattern of the evolution of the SAF over time. We use this as the basis for a new Bayesian hierarchical model to project future male and female ASAF from over 60 countries simultaneously. This gives forecasts as well as predictive distributions that can be used to find uncertainty intervals for any quantity of interest. We assess the model using out-of-sample predictive validation and find that it provides good forecasts and well-calibrated forecast intervals, comparing favorably with other methods.




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Regression for copula-linked compound distributions with applications in modeling aggregate insurance claims

Peng Shi, Zifeng Zhao.

Source: The Annals of Applied Statistics, Volume 14, Number 1, 357--380.

Abstract:
In actuarial research a task of particular interest and importance is to predict the loss cost for individual risks so that informative decisions are made in various insurance operations such as underwriting, ratemaking and capital management. The loss cost is typically viewed to follow a compound distribution where the summation of the severity variables is stopped by the frequency variable. A challenging issue in modeling such outcomes is to accommodate the potential dependence between the number of claims and the size of each individual claim. In this article we introduce a novel regression framework for compound distributions that uses a copula to accommodate the association between the frequency and the severity variables and, thus, allows for arbitrary dependence between the two components. We further show that the new model is very flexible and is easily modified to account for incomplete data due to censoring or truncation. The flexibility of the proposed model is illustrated using both simulated and real data sets. In the analysis of granular claims data from property insurance, we find substantive negative relationship between the number and the size of insurance claims. In addition, we demonstrate that ignoring the frequency-severity association could lead to biased decision-making in insurance operations.




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Distributional regression forests for probabilistic precipitation forecasting in complex terrain

Lisa Schlosser, Torsten Hothorn, Reto Stauffer, Achim Zeileis.

Source: The Annals of Applied Statistics, Volume 13, Number 3, 1564--1589.

Abstract:
To obtain a probabilistic model for a dependent variable based on some set of explanatory variables, a distributional approach is often adopted where the parameters of the distribution are linked to regressors. In many classical models this only captures the location of the distribution but over the last decade there has been increasing interest in distributional regression approaches modeling all parameters including location, scale and shape. Notably, so-called nonhomogeneous Gaussian regression (NGR) models both mean and variance of a Gaussian response and is particularly popular in weather forecasting. Moreover, generalized additive models for location, scale and shape (GAMLSS) provide a framework where each distribution parameter is modeled separately capturing smooth linear or nonlinear effects. However, when variable selection is required and/or there are nonsmooth dependencies or interactions (especially unknown or of high-order), it is challenging to establish a good GAMLSS. A natural alternative in these situations would be the application of regression trees or random forests but, so far, no general distributional framework is available for these. Therefore, a framework for distributional regression trees and forests is proposed that blends regression trees and random forests with classical distributions from the GAMLSS framework as well as their censored or truncated counterparts. To illustrate these novel approaches in practice, they are employed to obtain probabilistic precipitation forecasts at numerous sites in a mountainous region (Tyrol, Austria) based on a large number of numerical weather prediction quantities. It is shown that the novel distributional regression forests automatically select variables and interactions, performing on par or often even better than GAMLSS specified either through prior meteorological knowledge or a computationally more demanding boosting approach.




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Fast dynamic nonparametric distribution tracking in electron microscopic data

Yanjun Qian, Jianhua Z. Huang, Chiwoo Park, Yu Ding.

Source: The Annals of Applied Statistics, Volume 13, Number 3, 1537--1563.

Abstract:
In situ transmission electron microscope (TEM) adds a promising instrument to the exploration of the nanoscale world, allowing motion pictures to be taken while nano objects are initiating, crystalizing and morphing into different sizes and shapes. To enable in-process control of nanocrystal production, this technology innovation hinges upon a solution addressing a statistical problem, which is the capability of online tracking a dynamic, time-varying probability distribution reflecting the nanocrystal growth. Because no known parametric density functions can adequately describe the evolving distribution, a nonparametric approach is inevitable. Towards this objective, we propose to incorporate the dynamic evolution of the normalized particle size distribution into a state space model, in which the density function is represented by a linear combination of B-splines and the spline coefficients are treated as states. The closed-form algorithm runs online updates faster than the frame rate of the in situ TEM video, making it suitable for in-process control purpose. Imposing the constraints of curve smoothness and temporal continuity improves the accuracy and robustness while tracking the probability distribution. We test our method on three published TEM videos. For all of them, the proposed method is able to outperform several alternative approaches.




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On the probability distribution of the local times of diagonally operator-self-similar Gaussian fields with stationary increments

Kamran Kalbasi, Thomas Mountford.

Source: Bernoulli, Volume 26, Number 2, 1504--1534.

Abstract:
In this paper, we study the local times of vector-valued Gaussian fields that are ‘diagonally operator-self-similar’ and whose increments are stationary. Denoting the local time of such a Gaussian field around the spatial origin and over the temporal unit hypercube by $Z$, we show that there exists $lambdain(0,1)$ such that under some quite weak conditions, $lim_{n ightarrow+infty}frac{sqrt[n]{mathbb{E}(Z^{n})}}{n^{lambda}}$ and $lim_{x ightarrow+infty}frac{-logmathbb{P}(Z>x)}{x^{frac{1}{lambda}}}$ both exist and are strictly positive (possibly $+infty$). Moreover, we show that if the underlying Gaussian field is ‘strongly locally nondeterministic’, the above limits will be finite as well. These results are then applied to establish similar statements for the intersection local times of diagonally operator-self-similar Gaussian fields with stationary increments.




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Characterization of probability distribution convergence in Wasserstein distance by $L^{p}$-quantization error function

Yating Liu, Gilles Pagès.

Source: Bernoulli, Volume 26, Number 2, 1171--1204.

Abstract:
We establish conditions to characterize probability measures by their $L^{p}$-quantization error functions in both $mathbb{R}^{d}$ and Hilbert settings. This characterization is two-fold: static (identity of two distributions) and dynamic (convergence for the $L^{p}$-Wasserstein distance). We first propose a criterion on the quantization level $N$, valid for any norm on $mathbb{R}^{d}$ and any order $p$ based on a geometrical approach involving the Voronoï diagram. Then, we prove that in the $L^{2}$-case on a (separable) Hilbert space, the condition on the level $N$ can be reduced to $N=2$, which is optimal. More quantization based characterization cases in dimension 1 and a discussion of the completeness of a distance defined by the quantization error function can be found at the end of this paper.




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Willie Neville Majoribank Chester manuscript collection, 5 November 1915 - 22 December 1918




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Item 01: Notebooks (2) containing hand written copies of 123 letters from Major William Alan Audsley to his parents, ca. 1916-ca. 1919, transcribed by his father. Also includes original letters (2) written by Major Audsley.




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‘Selfish, tribal and divided’: Barack Obama warns of changes to American way of life in leaked audio slamming Trump administration

Barack Obama said the “rule of law is at risk” following the justice department’s decision to drop charges against former Trump advisor Mike Flynn, as he issued a stark warning about the long-term impact on the American way of life by his successor.





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Additive Multivariate Gaussian Processes for Joint Species Distribution Modeling with Heterogeneous Data

Jarno Vanhatalo, Marcelo Hartmann, Lari Veneranta.

Source: Bayesian Analysis, Volume 15, Number 2, 415--447.

Abstract:
Species distribution models (SDM) are a key tool in ecology, conservation and management of natural resources. Two key components of the state-of-the-art SDMs are the description for species distribution response along environmental covariates and the spatial random effect that captures deviations from the distribution patterns explained by environmental covariates. Joint species distribution models (JSDMs) additionally include interspecific correlations which have been shown to improve their descriptive and predictive performance compared to single species models. However, current JSDMs are restricted to hierarchical generalized linear modeling framework. Their limitation is that parametric models have trouble in explaining changes in abundance due, for example, highly non-linear physical tolerance limits which is particularly important when predicting species distribution in new areas or under scenarios of environmental change. On the other hand, semi-parametric response functions have been shown to improve the predictive performance of SDMs in these tasks in single species models. Here, we propose JSDMs where the responses to environmental covariates are modeled with additive multivariate Gaussian processes coded as linear models of coregionalization. These allow inference for wide range of functional forms and interspecific correlations between the responses. We propose also an efficient approach for inference with Laplace approximation and parameterization of the interspecific covariance matrices on the Euclidean space. We demonstrate the benefits of our model with two small scale examples and one real world case study. We use cross-validation to compare the proposed model to analogous semi-parametric single species models and parametric single and joint species models in interpolation and extrapolation tasks. The proposed model outperforms the alternative models in all cases. We also show that the proposed model can be seen as an extension of the current state-of-the-art JSDMs to semi-parametric models.




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A Bayesian Approach to Statistical Shape Analysis via the Projected Normal Distribution

Luis Gutiérrez, Eduardo Gutiérrez-Peña, Ramsés H. Mena.

Source: Bayesian Analysis, Volume 14, Number 2, 427--447.

Abstract:
This work presents a Bayesian predictive approach to statistical shape analysis. A modeling strategy that starts with a Gaussian distribution on the configuration space, and then removes the effects of location, rotation and scale, is studied. This boils down to an application of the projected normal distribution to model the configurations in the shape space, which together with certain identifiability constraints, facilitates parameter interpretation. Having better control over the parameters allows us to generalize the model to a regression setting where the effect of predictors on shapes can be considered. The methodology is illustrated and tested using both simulated scenarios and a real data set concerning eight anatomical landmarks on a sagittal plane of the corpus callosum in patients with autism and in a group of controls.




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Larry Brown’s Contributions to Parametric Inference, Decision Theory and Foundations: A Survey

James O. Berger, Anirban DasGupta.

Source: Statistical Science, Volume 34, Number 4, 621--634.

Abstract:
This article gives a panoramic survey of the general area of parametric statistical inference, decision theory and foundations of statistics for the period 1965–2010 through the lens of Larry Brown’s contributions to varied aspects of this massive area. The article goes over sufficiency, shrinkage estimation, admissibility, minimaxity, complete class theorems, estimated confidence, conditional confidence procedures, Edgeworth and higher order asymptotic expansions, variational Bayes, Stein’s SURE, differential inequalities, geometrization of convergence rates, asymptotic equivalence, aspects of empirical process theory, inference after model selection, unified frequentist and Bayesian testing, and Wald’s sequential theory. A reasonably comprehensive bibliography is provided.




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User-Friendly Covariance Estimation for Heavy-Tailed Distributions

Yuan Ke, Stanislav Minsker, Zhao Ren, Qiang Sun, Wen-Xin Zhou.

Source: Statistical Science, Volume 34, Number 3, 454--471.

Abstract:
We provide a survey of recent results on covariance estimation for heavy-tailed distributions. By unifying ideas scattered in the literature, we propose user-friendly methods that facilitate practical implementation. Specifically, we introduce elementwise and spectrumwise truncation operators, as well as their $M$-estimator counterparts, to robustify the sample covariance matrix. Different from the classical notion of robustness that is characterized by the breakdown property, we focus on the tail robustness which is evidenced by the connection between nonasymptotic deviation and confidence level. The key insight is that estimators should adapt to the sample size, dimensionality and noise level to achieve optimal tradeoff between bias and robustness. Furthermore, to facilitate practical implementation, we propose data-driven procedures that automatically calibrate the tuning parameters. We demonstrate their applications to a series of structured models in high dimensions, including the bandable and low-rank covariance matrices and sparse precision matrices. Numerical studies lend strong support to the proposed methods.




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Gaussian Integrals and Rice Series in Crossing Distributions—to Compute the Distribution of Maxima and Other Features of Gaussian Processes

Georg Lindgren.

Source: Statistical Science, Volume 34, Number 1, 100--128.

Abstract:
We describe and compare how methods based on the classical Rice’s formula for the expected number, and higher moments, of level crossings by a Gaussian process stand up to contemporary numerical methods to accurately deal with crossing related characteristics of the sample paths. We illustrate the relative merits in accuracy and computing time of the Rice moment methods and the exact numerical method, developed since the late 1990s, on three groups of distribution problems, the maximum over a finite interval and the waiting time to first crossing, the length of excursions over a level, and the joint period/amplitude of oscillations. We also treat the notoriously difficult problem of dependence between successive zero crossing distances. The exact solution has been known since at least 2000, but it has remained largely unnoticed outside the ocean science community. Extensive simulation studies illustrate the accuracy of the numerical methods. As a historical introduction an attempt is made to illustrate the relation between Rice’s original formulation and arguments and the exact numerical methods.




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Comment: Contributions of Model Features to BART Causal Inference Performance Using ACIC 2016 Competition Data

Nicole Bohme Carnegie.

Source: Statistical Science, Volume 34, Number 1, 90--93.

Abstract:
With a thorough exposition of the methods and results of the 2016 Atlantic Causal Inference Competition, Dorie et al. have set a new standard for reproducibility and comparability of evaluations of causal inference methods. In particular, the open-source R package aciccomp2016, which permits reproduction of all datasets used in the competition, will be an invaluable resource for evaluation of future methodological developments. Building upon results from Dorie et al., we examine whether a set of potential modifications to Bayesian Additive Regression Trees (BART)—multiple chains in model fitting, using the propensity score as a covariate, targeted maximum likelihood estimation (TMLE), and computing symmetric confidence intervals—have a stronger impact on bias, RMSE, and confidence interval coverage in combination than they do alone. We find that bias in the estimate of SATT is minimal, regardless of the BART formulation. For purposes of CI coverage, however, all proposed modifications are beneficial—alone and in combination—but use of TMLE is least beneficial for coverage and results in considerably wider confidence intervals.




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Dopamine D1 and D2 Receptor Family Contributions to Modafinil-Induced Wakefulness

Jared W. Young
Mar 4, 2009; 29:2663-2665
Journal Club




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Molecular cloning, functional properties, and distribution of rat brain alpha 7: a nicotinic cation channel highly permeable to calcium

P Seguela
Feb 1, 1993; 13:596-604
Articles




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Tribute to LP - :fsn:




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The lawyer who laundered political contributions




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Contribution of NPY Y5 Receptors to the Reversible Structural Remodeling of Basolateral Amygdala Dendrites in Male Rats Associated with NPY-Mediated Stress Resilience

Endogenous neuropeptide Y (NPY) and corticotrophin-releasing factor (CRF) modulate the responses of the basolateral amygdala (BLA) to stress and are associated with the development of stress resilience and vulnerability, respectively. We characterized persistent effects of repeated NPY and CRF treatment on the structure and function of BLA principal neurons in a novel organotypic slice culture (OTC) model of male rat BLA, and examined the contributions of specific NPY receptor subtypes to these neural and behavioral effects. In BLA principal neurons within the OTCs, repeated NPY treatment caused persistent attenuation of excitatory input and induced dendritic hypotrophy via Y5 receptor activation; conversely, CRF increased excitatory input and induced hypertrophy of BLA principal neurons. Repeated treatment of OTCs with NPY followed by an identical treatment with CRF, or vice versa, inhibited or reversed all structural changes in OTCs. These structural responses to NPY or CRF required calcineurin or CaMKII, respectively. Finally, repeated intra-BLA injections of NPY or a Y5 receptor agonist increased social interaction, a validated behavior for anxiety, and recapitulated structural changes in BLA neurons seen in OTCs, while a Y5 receptor antagonist prevented NPY's effects both on behavior and on structure. These results implicate the Y5 receptor in the long-term, anxiolytic-like effects of NPY in the BLA, consistent with an intrinsic role in stress buffering, and highlight a remarkable mechanism by which BLA neurons may adapt to different levels of stress. Moreover, BLA OTCs offer a robust model to study mechanisms associated with resilience and vulnerability to stress in BLA.

SIGNIFICANCE STATEMENT Within the basolateral amygdala (BLA), neuropeptide Y (NPY) is associated with buffering the neural stress response induced by corticotropin releasing factor, and promoting stress resilience. We used a novel organotypic slice culture model of BLA, complemented with in vivo studies, to examine the cellular mechanisms associated with the actions of NPY. In organotypic slice cultures, repeated NPY treatment reduces the complexity of the dendritic extent of anxiogenic BLA principal neurons, making them less excitable. NPY, via activation of Y5 receptors, additionally inhibits and reverses the increases in dendritic extent and excitability induced by the stress hormone, corticotropin releasing factor. This NPY-mediated neuroplasticity indicates that resilience or vulnerability to stress may thus involve neuropeptide-mediated dendritic remodeling in BLA principal neurons.




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Spotlight: How do pulses contribute to a sustainable world?

Pulses are being celebrated in 2016 all over the world since they are nutritious, suited for use in a variety of dishes, easy on the budget  and good for the health of the soil. From food security and nutrition to ensuring biodiversity and mitigating the effects of climate change, pulses contribute to sustainable development. Here is how.  1.     Nutritional benefits of pulses   Pulses [...]




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Nature's invisible connections and contributions to us

One person has curly hair; one person has straight hair. One person tans, another burns. One person can curl her lip, another can’t. This is all because of our genes and the differences in them. Diversity. It is the spice of life.  




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Bill to require AK to recognize tribes




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COVID-19 prompts changes to Thunder Bay's Ribfest

Changes are coming to Thunder Bay's popular Ribfest event because of the COVID-19 outbreak, organizers said.



  • News/Canada/Thunder Bay

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Remaining students describe life during lockdown at Laurentian University in Sudbury

Before COVID-19 hit, Hemliss Eloïse Konan had plans for how she'd spend her summer in Sudbury. After finishing her first year at Laurentian University, Konan planned to stay in residence, and get a job for the summer.



  • News/Canada/Sudbury

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Raftaar: Our biggest contribution will be to acknowledge the fact that the COVID warriors are doing a brilliant job

"I have tied up with several NGO’s like Parivartan the change who donate food to over 500 people every day as well with welfare organisations like 4dogsakeindia where we feed over 200 street dogs."



  • IMC News Feed

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To a sister, till we meet again – The Tribune India

To a sister, till we meet again  The Tribune India



  • IMC News Feed

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Pension contributions and tax-based incentives: evidence from the TCJA

We document that corporate pension contributions respond to tax-based incentives using the 2017 Tax Cut & Jobs Act (TCJA) as a natural experiment. The TCJA cut the U.S. federal corporate tax rate, temporarily increasing contribution incentives for sponsors of defined-benefit retirement plans. We exploit cross-sectional variation in ex-ante exposure to these incentives.




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Mutual funds' performance: the role of distribution networks and bank affiliation

Bank of Italy Working Papers by Giorgio Albareto, Andrea Cardillo, Andrea Hamaui and Giuseppe Marinelli




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Workers, capitalists, and the government: fiscal policy and income (re)distribution

Bank of England Working Papers by Cristiano Cantore and Lukas Freund




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Effect of Distributed Coupling on SPM

A Special Purpose Machine, which is intended to perform a specific task, have a wide range of scope in the Industrial Applications like quantity packaging and bottle filling. It includes limit switches, sensors, logic controls where the process can be

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A practical tribute to Dave and Joy Thomas

The OM Ships’ Thomas Guesthouse in South Carolina, USA, was dedicated to Dave and Joy Thomas, faithful members of OM Ships for 40 years.




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White Ribbons: 'I Will Never Forget You'

By Father Dave Pivonka, TOR

On the afternoon of March 6, I walked around the campus of Franciscan University of Steubenville, saying goodbye to students as they headed off for Spring Break. On that cold afternoon, it was unimaginable that those students wouldn’t come back to campus to finish out the school year. It was even more unimaginable that our University, where the Mass has always been at the center of campus life, would cease the public celebration of the Eucharist.

Tragically, at Franciscan University, like everywhere else, the global spread of the coronavirus quickly made the unimaginable our new reality.

I’ve been living with that new reality for over two weeks now, and I don’t like it. So, last week, I decided to do something about it: I hung a white ribbon on the door of our University chapel.
Let me explain.

It breaks my heart to not celebrate the Mass with students, faculty, staff, and their families. I miss the singing and the filled pews, the cries of babies and the responses of the faithful. Most of all, I miss Holy Communion; I miss giving Jesus to those hungry to receive him.

I understand why our bishops and leaders made the decisions they’ve made. I’m not questioning the necessity of those decisions. Extreme social distancing, for now, is a necessary evil.

Just the same, like my brother priests everywhere, I miss my people. I long for the day we can gather again, to worship, to listen to the Word of God, to preach and to receive Jesus in the Eucharist.

Until that day comes, however, I want the men and women I serve to know that they are always with me in thought and prayer, that I’m not letting a day go by without interceding for them before God, and that I could never forget them.

Even more important, I want them to know that God could never forget them. God didn’t forget his people when they wandered in the desert for 40 years. He didn’t forget them when they worshipped idols, ignored his commands, and found themselves exiled in Babylon. And he hasn’t forgotten us now.
 
Make no mistake: Our Lord does not like being separated from his people in this way. Jesus wants to give himself to us. He wants us to encounter him in the liturgy, in the Church, and in the Eucharist.
And this is where the white ribbons come in.

Ribbons have long been a sign of remembrance. They tell the world that we have not forgotten someone: a prisoner, a soldier, or a sick friend. I’ve tied a white ribbon onto the door of Christ the King Chapel, as well as the Portiuncula Chapel, here at Franciscan University, to remind our community that their priests and their God have not forgotten them. I’ve invited my friends who are priests and bishops to do the same. They, in turn, are inviting more priests and bishops to join us.

My hope is that as Catholics walk or drive past their churches, they will see those white ribbons and know their priests are praying for them and waiting for the day we can fling open those doors to welcome them back inside.

I also hope, when they see those ribbons, they know Jesus is waiting for that day, too. He longs for the day when we can gather together once more, and he can be with all of us, again, in the sacraments.

That day is not yet here. Like the Israelites of old, the Catholic faithful have to wander in exile a little longer. Jesus has not left us orphans, though. He is still with us. He is with us in the Scriptures, which are his Word. He is with us in his people—those we live with, work with, or encounter online. He is with us in prayer and in silence and in the beauty of his creation, which is singing his praises as spring finally comes.

Look for Jesus in all those places. Look for Jesus where you are. And when you see white ribbons hanging from a church door, remember God’s promise in Isaiah 49:15: “I will never forget you.”

In the midst of the chaos and the confusion, and the craziness, let those ribbons be a reminder that your priests are still with you. Let them be a reminder that Jesus is still with you. And let them be a reminder that one day soon, this exile will end, the churches will re-open, and your priests will be standing there, ready and waiting to joyfully welcome you home.



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Sharing with the Guarijios tribe

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Improving Antibiotic Prescribing for Pediatric Urinary Tract Infections in Outpatient Settings

OBJECTIVES:

To determine if a multicomponent intervention was associated with increased use of first-line antibiotics (cephalexin or sulfamethoxazole and trimethoprim) among children with uncomplicated urinary tract infections (UTIs) in outpatient settings.

METHODS:

The study was conducted at Kaiser Permanente Colorado, a large health care organization with ~127 000 members <18 years of age. After conducting a gap analysis, an intervention was developed to target key drivers of antibiotic prescribing for pediatric UTIs. Intervention activities included development of new local clinical guidelines, a live case-based educational session, pre- and postsession e-mailed knowledge assessments, and a new UTI-specific order set within the electronic health record. Most activities were implemented on April 26, 2017. The study design was an interrupted time series comparing antibiotic prescribing for UTIs before versus after the implementation date. Infants <60 days old and children with complex urologic or neurologic conditions were excluded.

RESULTS:

During January 2014 to September 2018, 2142 incident outpatient UTIs were identified (1636 preintervention and 506 postintervention). Pyelonephritis was diagnosed for 7.6% of cases. Adjusted for clustering of UTIs within clinicians, the proportion of UTIs treated with first-line antibiotics increased from 43.4% preintervention to 62.4% postintervention (P < .0001). The use of cephalexin (first-line, narrow spectrum) increased from 28.9% preintervention to 53.0% postintervention (P < .0001). The use of cefixime (second-line, broad spectrum) decreased from 17.3% preintervention to 2.6% postintervention (P < .0001). Changes in prescribing practices persisted through the end of the study period.

CONCLUSIONS:

A multicomponent intervention with educational and process-improvement elements was associated with a sustained change in antibiotic prescribing for uncomplicated pediatric UTIs.




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Reaching the tribe

Balboa, Panama :: Logos Hope's volunteers visit a Panamanian tribe on an isolated island which is being reached by the gospel.




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How to Subscribe to Podcasts on iOS, Mac, and iTunes

Apple's Podcasts app is available on mobile and the desktop, but in macOS Catalina, a new standalone Podcasts app replaces iTunes. Here's how to subscribe, listen, and adjust settings on iOS, iPadOS, iTunes, and Mac.