scholarly journals General Relative Rate Models for the Analysis of Studies Using Case-Cohort Designs

2018 ◽  
Vol 188 (2) ◽  
pp. 444-450
Author(s):  
David B Richardson ◽  
Bryan Langholz ◽  
Kaitlin Kelly-Reif
Keyword(s):  
Information Needs ◽  
Linear Models ◽  
Broad Class ◽  
Relative Rate ◽  
Model Misspecification ◽  
Model Fitting ◽  
Simple Random Sampling ◽  
Additional Information ◽  
Cohort Design ◽  
Cohort Data

Abstract A standard approach to analysis of case-cohort data involves fitting log-linear models. In this paper, we describe how standard statistical software can be used to fit a broad class of general relative rate models to case-cohort data and derive confidence intervals. We focus on a case-cohort design in which a roster has been assembled and events ascertained but additional information needs to be collected on explanatory variables. The additional information is ascertained just for persons who experience the event of interest and for a sample of the cohort members enumerated at study entry. One appeal of such a case-cohort design is that this sample of the cohort may be used to support analyses of several outcomes. The ability to fit general relative rate models to case-cohort data may allow an investigator to reduce model misspecification in exposure-response analyses, fit models in which some factors have effects that are additive and others multiplicative, and facilitate estimation of relative excess risk due to interaction. We address model fitting for simple random sampling study designs as well as stratified designs. Data on lung cancer among radon-exposed men (Colorado Plateau uranium miners, 1950–1990) are used to illustrate these methods.

The Development of ASHS HortBase—A Global Information System

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 552e-552
Author(s):  
James L. Green
Keyword(s):  
Information System ◽  
Information Needs ◽  
Standing Committee ◽  
Task Forces ◽  
Additional Information ◽  
Link Type ◽  
Dispersed System ◽  
Global Information System ◽  
Information File ◽  
International Standing

In 1997, the ASHS Board of Directors established ASHS HortBase as a Standing Committee of the Society. The ASHS HortBase Committee, a six-member Standing Committee and Chair, is charged to implement and maintain ASHS HortBase. The members of the ASHS HortBase Committee will be chair and chair-elect of the three HortBase Task Forces: 1) Finance and Marketing; 2) Standards—authoring, reviewing, and publishing; and 3) Technology. ASHS HortBase is a dispersed, dynamic horticultural information system (network) on the WWW comprised of peer—reviewed, concise, interlinked information modules to meet the information needs of instructors and students, gardeners and growers. A strong advantage and distinguishing characteristic of ASHS HortBase is our dynamic pool of potential authors, reviewers, and users (ASHS Extension, Industry, and Teaching membership) to continually evolve and update the peer-reviewed information in HortBase. We have the scholastic international standing to provide peer review and validation of the information and to recognition to the authors, coupled with the marketing to stimulate wide use of their information modules. ASHS HortBase is a dispersed system (dispersed development and server costs). The “dispersed cost” for information file development and updating and delivery on the respective authors' dispersed servers disperses the major costs of the HortBase information system. Additional information on ASHS HortBase and the papers presented at the 4-h Colloquium on HortBase at ASHS-97 can be found at http://[email protected] or contact me ([email protected], phone 541.737.5452, fax 541.737.3479).

Categorizing Blogs as Information Sources for Libraries and Information Science

2015 ◽  
pp. 4833-4845
Author(s):  
Mark-Shane Scale ◽  
Anabel Quan-Haase
Keyword(s):  
Social Media ◽  
Information Needs ◽  
Information Sources ◽  
Information Science ◽  
Information Source ◽  
Future Research ◽  
Collection Development ◽  
Sources Of Information ◽  
Additional Information ◽  
Source Category

Blogs are important sources of information currently used in the work of professionals, institutions and academics. Nevertheless, traditional information needs and uses research has not yet discussed where blogs fit in the existing typologies of information sources. Blogs and other types of social media have several characteristics that blur the lines of distinction existent between traditional information source categories. This chapter brings this research problem to the fore. Not only do we examine why blogs do not neatly fit into existing information source categories, but we also deliberate the implications for libraries in terms of the need to consider blogs as an information source to be included in collection development. We discuss the opportunities and possibilities for blogs to be integrated into the collection development efforts of academic and public libraries to better serve patrons. In order to accommodate for blogs and other types of social media as information sources, we propose the introduction of an additional information source category. We suggest new avenues of future research that investigate how blogs are being used to meet information needs in various social settings, such as corporations, health care and educational settings (e.g., higher education, and schools). In this chapter, we develop a framework of how blogs may function as information sources to provide libraries with a better understanding of how blogs are integrated into the context of everyday information seeking. By grouping the ways in which people employ blogs to acquire information, we propose that blogs provide information sources along a continuum ranging from non-fiction to fictional information.

scholarly journals Jeffreys-prior penalty, finiteness and shrinkage in binomial-response generalized linear models

Biometrika ◽  
2020 ◽  
Author(s):  
Ioannis Kosmidis ◽  
David Firth
Keyword(s):  
Maximum Likelihood ◽  
Maximum Likelihood Estimator ◽  
Generalized Linear Models ◽  
Linear Models ◽  
Broad Class ◽  
Penalized Likelihood ◽  
Jeffreys Prior ◽  
Likelihood Estimator ◽  
Maximum Penalized Likelihood ◽  
Binomial Response

Summary Penalization of the likelihood by Jeffreys’ invariant prior, or a positive power thereof, is shown to produce finite-valued maximum penalized likelihood estimates in a broad class of binomial generalized linear models. The class of models includes logistic regression, where the Jeffreys-prior penalty is known additionally to reduce the asymptotic bias of the maximum likelihood estimator, and models with other commonly used link functions, such as probit and log-log. Shrinkage towards equiprobability across observations, relative to the maximum likelihood estimator, is established theoretically and studied through illustrative examples. Some implications of finiteness and shrinkage for inference are discussed, particularly when inference is based on Wald-type procedures. A widely applicable procedure is developed for computation of maximum penalized likelihood estimates, by using repeated maximum likelihood fits with iteratively adjusted binomial responses and totals. These theoretical results and methods underpin the increasingly widespread use of reduced-bias and similarly penalized binomial regression models in many applied fields.

Generalized Log-Linear Models of Housing Choice

1988 ◽  
Vol 20 (1) ◽  
pp. 55-69 ◽  
Author(s):  
M C Deurloo ◽  
F M Dieleman ◽  
W A V Clark
Keyword(s):  
Linear Models ◽  
Nonlinear Effects ◽  
Design Matrix ◽  
Housing Choice ◽  
Ordered Categories ◽  
Public And Private ◽  
Income Effects ◽  
Additional Information ◽  
Log Linear

By incorporating the structure of polytomous variables with ordered categories in the design matrix, nonstandard logit models are used to analyze housing choice. The detailed effects of income, age, and type of housing market on choice are examined. The additional information that is incorporated in the modeling leads to a more parsimonious representation of the data. The results confirm the central and substantial role of income; income effects are linear for owners but there are nonlinear effects for public and private renters. There are important age and region interaction effects on choice for households originally in the rental sector, and for former owners the value of the previous dwelling influences choice.

Doubly Robust Estimation with the R Package drgee

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Johan Zetterqvist ◽  
Arvid Sjölander
Keyword(s):  
Robust Estimation ◽  
Linear Models ◽  
Model Misspecification ◽  
R Package ◽  
Epidemiologic Research ◽  
Important Concern ◽  
Doubly Robust Estimation ◽  
Unbiased Estimates ◽  
Doubly Robust ◽  
Biased Estimates

AbstractA common goal of epidemiologic research is to study the association between a certain exposure and a certain outcome, while controlling for important covariates. This is often done by fitting a restricted mean model for the outcome, as in generalized linear models (GLMs) and in generalized estimating equations (GEEs). If the covariates are high-dimensional, then it may be difficult to well specify the model. This is an important concern, since model misspecification may lead to biased estimates. Doubly robust estimation is an estimation technique that offers some protection against model misspecification. It utilizes two models, one for the outcome and one for the exposure, and produces unbiased estimates of the exposure-outcome association if either model is correct, not necessarily both. Despite its obvious appeal, doubly robust estimation is not used on a regular basis in applied epidemiologic research. One reason for this could be the lack of up-to-date software. In this paper we describe a new

scholarly journals Kinetic study of the gas-phase reaction of atomic chlorine with a series of aldehydes

2005 ◽  
Vol 5 (12) ◽  
pp. 3433-3440 ◽  
Author(s):  
D. Rodríguez ◽  
A. Rodríguez ◽  
A. Notario ◽  
A. Aranda ◽  
Y. Díaz-de-Mera ◽  
...  
Keyword(s):  
Relative Rate ◽  
Weighted Average ◽  
Rate Coefficients ◽  
Phase Reaction ◽  
Additional Information ◽  
Relative Rate Constants ◽  
Relative Measurements ◽  
First Time ◽  
Structure Versus ◽  
Atomic Chlorine

Abstract. The reactions of Cl atoms with a series of unsaturated aldehydes have been investigated for the first time using a relative method. In order to obtain additional information for a qualitative structure versus reactivity discussion, we have also determined the rate coefficients for the reactions of atomic chlorine with their respective saturated aldehydes. These relative measurements were performed at room temperature and atmospheric pressure of air and N2, by using ethane, propene and 1-butene as reference compounds. The weighted average relative rate constants obtained, kCl±2σ (in units of cm3 molecule−1 s−1) were: trans-2-pentenal (1.31±0.19)×10−10; trans-2-hexenal (1.92±0.22)×10−10; trans-2-heptenal (2.40±0.29)×10−10; n-pentanal (2.56±0.27)×10−10; n-hexanal (2.88±0.37)×10−10; n-heptanal (3.00±0.34)×10−10. Finally, results and atmospheric implications are discussed and compared with the reactivity with OH and NO3 radicals.

scholarly journals Interpretation of the event within the structure of news narrative

Litera ◽  
2021 ◽  
pp. 102-117
Author(s):  
Marina Aleksandrovna Deminova
Keyword(s):  
Information Needs ◽  
Editorial Policy ◽  
Narrative Structure ◽  
Stable Structure ◽  
Value System ◽  
Additional Information ◽  
Actual Event ◽  
Special Place ◽  
News Writing ◽  
Media Texts

This article is dedicated to the analysis of the structure of news narrative, which is relevant the context of interpretation of the event. The author believes that the news texts that do not contain a clear expressive or analytical component, interpretation consists in transformation of the narrative. News hold a special place among other media texts. News genres, to a greater extent that the analytical genres, satisfy people's information needs. If the analytical and publicistic texts the readers choose in accordance with their worldview and value system, then news texts are perceived as neutral, characterized by a stable structure, repeatability, reproducibility; they are virtually not affected by the specificity of a particular editorial policy, and, thus, have broader audience. At first glance, the patterns used for news writing, do not have impact on the audience; however, they are evaluative and interpretative, which is reflected in narrative structure of the text. The attitude of the author towards the event in the central episode is traced. Since the central episode is related to the actual event more than any other component of the narrative structure, it nonetheless, has considerable interpretive potential. Transformation of the key component testifies to the fact that narrative structure of the news material is quite adaptable, and may change under the influence of certain information. The additional secondary components of the narrative structure also have high interpretive potential, since their very presence in the text reflects the author's desire to deliver additional information, the choice of which directly affects interpretation of the event.

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