Use of a General Dose–Response Model for Rockfish Fecundity–Length Relationships

1990 ◽  
Vol 47 (6) ◽  
pp. 1148-1156 ◽  
Author(s):  
Laura J. Richards ◽  
Jon T. Schnute
Keyword(s):  
Dose Response ◽  
Regression Models ◽  
Data Sets ◽  
Response Model ◽  
Exact Inference ◽  
Special Cases ◽  
Wide Range ◽  
Length Data ◽  
The Relationship ◽  
General Method

In this paper we describe a general method for determining the relationship between fecundity and another fish attribute, such as size or age. Our methods include linear and logarithmic regression models as special cases and are applicable to a wide range of situations. The model we propose is based on the univariate form of the Schnute–Jensen dose–response model. However, we extend the Schnute–Jensen analysis by describing exact inference regions obtained from likelihood contours, to which we assign nominal probability levels. We also provide a method for obtaining an inference band for the predicted curve. We examine the issue of model adequacy as it relates to fecundity–length data from two rockfish (Sebastes) species. We show that the extra complexity of our model is justified, as none of the traditional regression models are appropriate for all three of our data sets. Further, we use inference bands to distinguish fecundity–length relationships for quillback rockfish (S. maliger) from two areas, but we are unable to distinguish one of these relationships from a similar relationship for copper rockfish (S. caurinus).

scholarly journals The differential role of practical and emotional support in infant feeding experience in the UK

2021 ◽  
Vol 376 (1827) ◽  
Author(s):  
S. Myers ◽  
A. E. Page ◽  
E. H. Emmott
Keyword(s):  
Social Support ◽  
Infant Feeding ◽  
Regression Models ◽  
Cox Regression ◽  
Nuclear Family ◽  
Maternal Child Health ◽  
Feeding Experience ◽  
Wide Range ◽  
The Uk ◽  
The Relationship

Social support is a known determinant of breastfeeding behaviour and is generally considered beneficial. However, social support encompasses a myriad of different supportive acts, providing scope for diverse infant feeding outcomes. Given the vulnerability of postpartum mental health, this paper aims to explore both how support prolongs breastfeeding and which forms of support promote the positive experience of all infant feeding. Using survey data collected online from 515 UK mothers with infants aged 0–108 weeks, Cox regression models assessed the relationship between receiving different types of support, support need and breastfeeding duration. Quasi-binomial logistic regression models assessed the relationship between receiving support, infant feeding mode and maternal experience of infant feeding. Rates of negative infant feeding experience indicate the widespread need for support: e.g. 38% of currently, 47% of no longer and 31% of never breastfeeding women found infant feeding stressful. Overall, practical support via infant feeding broadly predicted shorter breastfeeding durations and poorer feeding experience; results in relation to other forms of support were more complex. Our findings indicate different forms of support have different associations with infant feeding experience. They also highlight the wide range of individuals beyond the nuclear family on which postpartum mothers in the UK rely. This article is part of the theme issue ‘Multidisciplinary perspectives on social support and maternal–child health’.

scholarly journals Estimating Contextual Effects from Ego Network Data

2020 ◽  
Vol 50 (1) ◽  
pp. 215-275
Author(s):  
Jeffrey A. Smith ◽  
G. Robin Gauthier
Keyword(s):  
Mental Health ◽  
Social Context ◽  
Network Analysis ◽  
Data Collection ◽  
Regression Models ◽  
Hierarchical Linear Model ◽  
Contextual Effects ◽  
Network Data ◽  
Data Sets ◽  
The Relationship

Network concepts are often used to characterize the features of a social context. For example, past work has asked if individuals in more socially cohesive neighborhoods have better mental health outcomes. Despite the ubiquity of use, it is relatively rare for contextual studies to use the methods of network analysis. This is the case, in part, because network data are difficult to collect, requiring information on all ties between all actors. In this article the authors ask whether it is possible to avoid such heavy data collection while still retaining the best features of a contextual-network study. The basic idea is to apply network sampling to the problem of contextual models, in which one uses sampled ego network data to infer the network features of each context and then uses the inferred network features as second-level predictors in a hierarchical linear model. The authors test the validity of this idea in the case of network cohesion. Using two complete data sets as a test, the authors find that ego network data are sufficient to capture the relationship between cohesion and important outcomes, such as attachment and deviance. The hope, going forward, is that researchers will find it easier to incorporate holistic network measures into traditional regression models.

scholarly journals The Differential Role of Practical and Emotional Support in Infant Feeding Experience in the UK

2020 ◽  
Author(s):  
Sarah Myers ◽  
Abigail Emma Page ◽  
Emily H Emmott
Keyword(s):  
Social Support ◽  
Infant Feeding ◽  
Regression Models ◽  
Cox Regression ◽  
Nuclear Family ◽  
Feeding Mode ◽  
Young Infants ◽  
Feeding Experience ◽  
Wide Range ◽  
The Relationship

Social support is a known determinant of breastfeeding behaviour and is generally considered beneficial. However, social support encompasses a myriad of different supportive acts, providing scope for diverse consequences. Given the vulnerability of postpartum mental health, it is crucial to understand not only how support prolongs breastfeeding, but which forms of support promote the positive experience of all infant feeding. Using survey data collected from 515 UK mothers with young infants, we ran cox regression models to assess the relationship between receiving different types of support, support need, and the duration breastfeeding. Quasi-binomial logistic regression models assessed the relationship between receiving support, infant feeding mode, and maternal experience of infant feeding. Overall, infant feeding support broadly predicted shorter breastfeeding durations and poorer feeding experience; results in relation to other forms of support were more complex. 38% of breastfeeding women found it stressful and 42% emotionally draining and rates were higher in non-breastfeeding women, emphasising the widespread need for support. Our findings endorse the contention that social support should not be treated as a univariate entity with uniform outcomes, as well as highlight the wide range of individuals beyond the nuclear family on which mothers in a high-income setting rely.

scholarly journals Computationally scalable regression modeling for ultrahigh-dimensional omics data with ParProx

2021 ◽  
Author(s):  
Seyoon Ko ◽  
Ginny X. Li ◽  
Hyungwon Choi ◽  
Joong-Ho Won
Keyword(s):  
Association Analysis ◽  
Regression Models ◽  
Model Fitting ◽  
Data Sets ◽  
Omics Data ◽  
Lasso Regression ◽  
Independent Variables ◽  
Wide Range ◽  
Sequencing Studies ◽  
Genomic Regions

AbstractStatistical analysis of ultrahigh-dimensional omics scale data has long depended on univariate hypothesis testing. With growing data features and samples, the obvious next step is to establish multivariable association analysis as a routine method for understanding genotype-phenotype associations. Here we present ParProx, a state-of-the-art implementation to optimize overlapping group lasso regression models for time-to-event and classification analysis, guided by biological priors through coordinated variable selection. ParProx not only enables model fitting for ultrahigh-dimensional data within the architecture for parallel or distributed computing, but also allows users to obtain interpretable regression models consistent with known biological relationships among the independent variables, a feature long neglected in statistical modeling of omics data. We demonstrate ParProx using three different omics data sets of moderate to large numbers of variables, where we use genomic regions and pathways to arrive at sparse regression models comprised of biologically related independent variables. ParProx is naturally applicable to a wide range of studies using ultrahigh-dimensional omics data, ranging from genome-wide association analysis to single cell sequencing studies where multivariable modeling is computationally intractable.

The Effects of Body-Worn Cameras on Violent Police Victimization

2020 ◽  
Author(s):  
Stephen Douglas
Keyword(s):  
Police Officers ◽  
Data Sets ◽  
Law Enforcement Agencies ◽  
Research Attention ◽  
Police Organizations ◽  
Wide Range ◽  
Police Agencies ◽  
Citizen Interactions ◽  
The Impact ◽  
The Relationship

Abstract Body-worn cameras (BWCs) have been presented as a technological innovation to cultivate greater civility in police–citizen interactions. Attempts have been made to clarify the impact of BWCs upon various policing outcomes, but the effects of BWCs on assaults against police has received scant research attention. Existing studies have been limited to a handful of jurisdictions with limited generalizability to a broader range of police organizations. Combining a number of official data sets for the years 2011–13, the current study assesses the relationship between BWCs and police victimization by focusing on total assaults and firearm assaults against police officers in a sample of 516 police agencies. The results indicate that BWC usage is negatively associated with police victimization in both models. This suggests that BWCs can assist in preventing the occurrence of general and extreme violence against police in a wide range of law enforcement agencies in varied settings.

Measurement of fabric handle characteristics based on the Quick-Intelligent Handle Evaluation System for Fabrics (QIHES-F)

2018 ◽  
Vol 89 (16) ◽  
pp. 3374-3386
Author(s):  
Yi Sun ◽  
Mingyue Zhang ◽  
Gui Liu ◽  
Zhaoqun Du
Keyword(s):  
Evaluation System ◽  
Regression Models ◽  
Prediction Models ◽  
American Association ◽  
Subjective Evaluation ◽  
Fabric Handle ◽  
Wide Range ◽  
Objective Tests ◽  
The Relationship ◽  
Force Displacement

A quick-intelligent handle evaluation system for fabrics (QIHES-F) was developed to evaluate tactile perceptions of fabric by measuring thickness and multiple mechanical properties of fabrics via a single testing process. The main aim dealt with in this study was to establish optimal and suitable regression models by a stepwise regression method based on the QIHES-F and human sensations of fabrics, thereby estimating total handle values effectively. Subjective evaluation by American Association of Textile Chemists and Colorists EP5-2007 and objective tests by QIHES-F of a wide range of 50 fabrics were conducted, to predict fabric handle from four primary handle characteristics and total handle values. Five prediction models corresponding to the fullness, stiffness, roughness, tightness and total handle of fabrics were built based on featured indexes to analyze the relationship between the subjective handle and experimental curve parameters. The indexes were featured from the force-displacement curves of QIHES-F. The results show that these featured indexes can be treated as indicators to characterize fabric properties, and that the five corresponding prediction models can predict handle characteristics of fabrics reliably, as the Pearson’s coefficients and adjusted coefficients are high. They indicate that QIHES-F can directly and accurately obtain fabric handle values and can evaluate the grades of fabric quality.

Gender governs the relationship between exercise intensity and growth hormone release in young adults

2002 ◽  
Vol 92 (5) ◽  
pp. 2053-2060 ◽  
Author(s):  
Cathy J. Pritzlaff-Roy ◽  
Laurie Widemen ◽  
Judy Y. Weltman ◽  
Rob Abbott ◽  
Margaret Gutgesell ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Young Adults ◽  
Production Rate ◽  
Dose Response ◽  
Exercise Intensity ◽  
Regression Models ◽  
Gh Secretion ◽  
Linear Dose ◽  
The Difference ◽  
The Relationship

We previously reported that in young adult males growth hormone (GH) release is related to exercise intensity in a linear dose-response manner (Pritzlaff et al. J Appl Physiol 87: 498–504, 1999). To investigate the effects of gender and exercise intensity on GH release, eight women (24.3 ± 1.3 yr, 171 ± 3.2 cm height, 63.6 ± 8.7 kg weight) were each tested on six randomly ordered occasions [1 control condition (C), 5 exercise conditions (Ex)]. Serum GH concentrations were measured in samples obtained at 10-min intervals between 0700 and 0900 (baseline) and 0900 and 1300 (Ex + recovery or C). Integrated GH concentrations (IGHC) were calculated by trapezoidal reconstruction. During Ex, subjects exercised for 30 min (0900–0930) at one of the following intensities [normalized to the lactate threshold (LT)]: 25 and 75% of the difference between LT and rest, at LT, and at 25 and 75% of the difference between LT and peak O2 uptake. No differences were observed among conditions for baseline IGHC. To determine whether total (Ex + recovery) IGHC changed with increasing exercise intensity, slopes associated with individual linear regression models were subjected to a Wilcoxon signed-rank test. To test for gender differences, data in women were compared with the previously published data in men. A Wilcoxon ranked-sums two-tailed test was used to analyze the slopes and intercepts from the regression models. Total IGHC increased linearly with increasing exercise intensity. The slope and intercept values for the relationship between total IGHC and exercise intensity were greater in women than in men. Deconvolution analysis (0700–1300 h) revealed that, regardless of gender, increasing exercise intensity resulted in a linear increase in the mass of GH secreted per pulse and summed GH production rate, with no changes in GH secretory pulse frequency or apparent half-life of elimination. Exercise reduced the half-duration of GH secretory burst in men but not in women. Gender comparisons revealed that women had greater basal (nonpulsatile) GH secretion across all conditions, more frequent GH secretory pulses, a greater GH secretory pulse amplitude, a greater production rate, and a trend for a greater mass of GH secreted per pulse than men. We conclude that, in young adults, the GH secretory response to exercise is related to exercise intensity in a linear dose-response pattern. For each incremental increase in exercise intensity, the fractional stimulation of GH secretion is greater in women than in men.

MODELLING INSURANCE LOSSES USING CONTAMINATED GENERALISED BETA TYPE-II DISTRIBUTION

2018 ◽  
Vol 48 (02) ◽  
pp. 871-904 ◽  
Author(s):  
J.S.K. Chan ◽  
S.T.B. Choy ◽  
U.E. Makov ◽  
Z. Landsman
Keyword(s):  
Heavy Tails ◽  
Insurance Companies ◽  
Parameter Distribution ◽  
Data Sets ◽  
Type Ii ◽  
Gamma Distributions ◽  
Special Cases ◽  
Wide Range ◽  
Distribution Family ◽  
Quantile Estimates

AbstractThe four-parameter distribution family, the generalised beta type-II (GB2), also known as the transformed beta distribution, has been proposed for modelling insurance losses. As special cases, this family nests many distributions with light and heavy tails, including the lognormal, gamma, Weibull, Burr and generalised gamma distributions. This paper extends the GB2 family to the contaminated GB2 family, which offers many flexible features, including bimodality and a wide range of skewness and kurtosis. Properties of the contaminated distribution are derived and evaluated in a simulation study and the suitability of the contaminated GB2 distribution for actuarial purposes is demonstrated through two real loss data sets. Analysis of tail quantiles for the data suggests large differences in extreme quantile estimates for different loss distribution assumptions, showing that the selection of appropriate distributions has a significant impact for insurance companies.

scholarly journals The relationship between feed intake and liveweight in domestic animals

2020 ◽  
Vol 98 (4) ◽  
Author(s):  
Ronald M Lewis ◽  
Gerry C Emmans
Keyword(s):  
Feed Intake ◽  
Good Description ◽  
Domestic Animal ◽  
Data Sets ◽  
General Description ◽  
Wide Range ◽  
Functional Forms ◽  
Degree Of Maturity ◽  
Multiple Species ◽  
The Relationship

Abstract Feed intake changes as animals age and grow. A constraint of most functional forms used to describe this relationship is that intake is maximum only once an animal reaches its mature weight. Often such is not the case and maximum intake is achieved earlier. Our aim was to describe a form unburdened by such a constraint and to determine its utility to describe the relationship between feed intake and liveweight across multiple species. Twelve data sets representing seven domestic animal species (cattle, chicken, dog, pig, rat, sheep, and turkey) with a wide range of mature weights were used. Average daily ad libitum feed intakes and liveweights were available on either a weekly or fortnightly basis. Rates of intake were scaled to mature intake. Within each set, the quadratic regression of scaled intake on the degree of maturity in weight was fitted. This form provided a very good description of the relationship between these variables (R2 > 0.86) and, for all but one case, a realistic prediction of mature intake. With one exception, intake reached its maximum value at a liveweight below its mature value. Furthermore, by appropriately scaling the relationship between intake and liveweight, the data could be described by a function with a single parameter with general relevance across species. By expressing the rate of intake as a function of its value at maturity, a quadratic form provides a robust and general description of the relationship between feed intake scaled to mature intake and degree of maturity in weight.

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