A new approach to varying-coefficient additive models with longitudinal covariates

2020 ◽  
Vol 145 ◽  
pp. 106912
Author(s):  
Xiaoke Zhang ◽  
Qixian Zhong ◽  
Jane-Ling Wang
Keyword(s):  
Additive Models ◽  
New Approach ◽  
Varying Coefficient ◽  
Longitudinal Covariates

scholarly journals Characterizing Behavioral Activity Rhythms in Older Adults Using Actigraphy

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 549
Author(s):  
Ariel B. Neikrug ◽  
Ivy Y. Chen ◽  
Jake R. Palmer ◽  
Susan M. McCurry ◽  
Michael Von Korff ◽  
...  
Keyword(s):  
Older Adults ◽  
Older Adult ◽  
Activity Patterns ◽  
Additive Models ◽  
Behavioral Activity ◽  
New Approach ◽  
Activity Rhythms ◽  
Activity Measurements ◽  
Wrist Actigraphy

Wrist actigraphy has been used to assess sleep in older adult populations for nearly half a century. Over the years, the continuous raw activity data derived from actigraphy has been used for the characterization of factors beyond sleep/wake such as physical activity patterns and circadian rhythms. Behavioral activity rhythms (BAR) are useful to describe individual daily behavioral patterns beyond sleep and wake, which represent important and meaningful clinical outcomes. This paper reviews common rhythmometric approaches and summarizes the available data from the use of these different approaches in older adult populations. We further consider a new approach developed in our laboratory designed to provide graphical characterization of BAR for the observed behavioral phenomenon of activity patterns across time. We illustrate the application of this new approach using actigraphy data collected from a well-characterized sample of older adults (age 60+) with osteoarthritis (OA) pain and insomnia. Generalized additive models (GAM) were implemented to fit smoothed nonlinear curves to log-transformed aggregated actigraphy-derived activity measurements. This approach demonstrated an overall strong model fit (R2 = 0.82, SD = 0.09) and was able to provide meaningful outcome measures allowing for graphical and parameterized characterization of the observed activity patterns within this sample.

Testing in nonparametric varying coefficient additive models

2011 ◽  
Vol 21 (2) ◽  
pp. 749 ◽  
Author(s):  
Byeong U. Park ◽  
Jun H. Hwang ◽  
Min S. Park
Keyword(s):  
Additive Models ◽  
Varying Coefficient

scholarly journals 3D Fine-scale Terrain Variables from Underwater Photogrammetry: A New Approach to Benthic Microhabitat Modeling in a Circalittoral Rocky Shelf

2020 ◽  
Vol 12 (15) ◽  
pp. 2466
Author(s):  
Elena Prado ◽  
Augusto Rodríguez-Basalo ◽  
Adolfo Cobo ◽  
Pilar Ríos ◽  
Francisco Sánchez
Keyword(s):  
Deep Learning ◽  
Learning Algorithm ◽  
High Reliability ◽  
3D Models ◽  
Additive Models ◽  
Fine Scale ◽  
New Approach ◽  
Deep Learning Algorithm ◽  
The Relationship ◽  
Very High

The relationship between 3D terrain complexity and fine-scale localization and distribution of species is poorly understood. Here we present a very fine-scale 3D reconstruction model of three zones of circalittoral rocky shelf in the Bay of Biscay. Detailed terrain variables are extracted from 3D models using a structure-from-motion (SfM) approach applied to ROTV images. Significant terrain variables that explain species location were selected using general additive models (GAMs) and micro-distribution of the species were predicted. Two models combining BPI, curvature and rugosity can explain 55% and 77% of the Ophiuroidea and Crinoidea distribution, respectively. The third model contributes to explaining the terrain variables that induce the localization of Dendrophyllia cornigera. GAM univariate models detect the terrain variables for each structural species in this third zone (Artemisina transiens, D. cornigera and Phakellia ventilabrum). To avoid the time-consuming task of manual annotation of presence, a deep-learning algorithm (YOLO v4) is proposed. This approach achieves very high reliability and low uncertainty in automatic object detection, identification and location. These new advances applied to underwater imagery (SfM and deep-learning) can resolve the very-high resolution information needed for predictive microhabitat modeling in a very complex zone.

Varying-coefficient additive models for functional data

Biometrika ◽  
2014 ◽  
Vol 102 (1) ◽  
pp. 15-32 ◽  
Author(s):  
X. Zhang ◽  
J.-L. Wang
Keyword(s):  
Functional Data ◽  
Additive Models ◽  
Varying Coefficient

scholarly journals Wealth 2D – An alternative approach to explore wealth effects

2021 ◽  
Author(s):  
Jascha Dräger ◽  
Klaus Pforr ◽  
Nora Müller
Keyword(s):  
Generalized Additive Models ◽  
Predictor Variable ◽  
Additive Models ◽  
Wealth Effects ◽  
New Approach ◽  
Net Worth ◽  
Alternative Approach ◽  
The Us ◽  
The Common ◽  
Research Questions

The analysis of wealth as a predictor variable comes with several conceptual and methodological challenges with important consequences for results. We propose to employ Generalized Additive Models and jointly evaluating gross wealth and debt when exploring wealth effects to overcome the dependence of results on implausible assumptions. First, we conduct a simulation study and find that this new approach describes systematic wealth differences in more detail than the common approaches and is less likely to overfit random variation in the data. Next, we apply the new approach to re-analyze wealth gaps in educational attainment in the US. In contrast to existing research, we find that it is not negative net worth that is associated with the worst educational prospects but the combination of low gross wealth and low debt. Children in households with high gross wealth have the best prospects almost independent of household debt. The approach can be easily adapted to other research questions.

The O–C diagrams of minor planets − a new approach to modelling the rotation

1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss
Keyword(s):  
Error Analysis ◽  
Time Dependence ◽  
Theoretical Work ◽  
Minor Planet ◽  
Minor Planets ◽  
New Approach ◽  
Preliminary Results ◽  
Ccd Observations

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.

A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

1973 ◽  
Vol 31 ◽  
pp. 698-699
Author(s):  
V. Mizuhira ◽  
Y. Futaesaku
Keyword(s):  
Cross Section ◽  
Tannic Acid ◽  
Elastic Fiber ◽  
The Other ◽  
New Approach ◽  
Tissue Block ◽  
Active Reaction ◽  
The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

Processing Immunoperoxidase Labeled Cell Monolayers and Cryostat Sesctions For Electron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 714-715
Author(s):  
K. Chien ◽  
R. Van de Velde ◽  
I.P. Shintaku ◽  
A.F. Sassoon
Keyword(s):  
Cell Monolayer ◽  
Cell Types ◽  
Surface Antigens ◽  
Immunoperoxidase Method ◽  
Reaction Step ◽  
Hot Plate ◽  
Air Drying ◽  
New Approach ◽  
Cell Monolayers ◽  
Glass Slides

Immunoelectron microscopy of neoplastic lymphoma cells is valuable for precise localization of surface antigens and identification of cell types. We have developed a new approach in which the immunohistochemical staining can be evaluated prior to embedding for EM and desired area subsequently selected for ultrathin sectioning.A freshly prepared lymphoma cell suspension is spun onto polylysine hydrobromide- coated glass slides by cytocentrifugation and immediately fixed without air drying in polylysine paraformaldehyde (PLP) fixative. After rinsing in PBS, slides are stained by a 3-step immunoperoxidase method. Cell monolayer is then fixed in buffered 3% glutaraldehyde prior to DAB reaction. After the DAB reaction step, wet monolayers can be examined under LM for presence of brown reaction product and selected monolayers then processed by routine methods for EM and embedded with the Chien Re-embedding Mold. After the polymerization, the epoxy blocks are easily separated from the glass slides by heatingon a 100°C hot plate for 20 seconds.

TEM study of a biofilm on copper corrosion

1996 ◽  
Vol 54 ◽  
pp. 220-221
Author(s):  
W. A. Chiou ◽  
N. Kohyama ◽  
B. Little ◽  
P. Wagner ◽  
M. Meshii
Keyword(s):  
Marine Bacterium ◽  
Culture Medium ◽  
Copper Alloys ◽  
Pure Copper ◽  
Localized Corrosion ◽  
Natural Seawater ◽  
Copper Corrosion ◽  
New Approach ◽  
The Past ◽  
Copper Tolerant

The corrosion of copper and copper alloys in a marine environment is of great concern because of their widespread use in heat exchangers and steam condensers in which natural seawater is the coolant. It has become increasingly evident that microorganisms play an important role in the corrosion of a number of metals and alloys under a variety of environments. For the past 15 years the use of SEM has proven to be useful in studying biofilms and spatial relationships between bacteria and localized corrosion of metals. Little information, however, has been obtained using TEM capitalizing on its higher spacial resolution and the transmission observation of interfaces. The research presented herein is the first step of this new approach in studying the corrosion with biological influence in pure copper.Commercially produced copper (Cu, 99%) foils of approximately 120 μm thick exposed to a copper-tolerant marine bacterium, Oceanospirillum, and an abiotic culture medium were subsampled (1 cm × 1 cm) for this study along with unexposed control samples.

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