scholarly journals New models for the time dependent toxicity of individual and combined toxicants

2019 ◽  
Vol 8 (4) ◽  
pp. 509-521 ◽  
Author(s):  
Ronald J. W. Lambert ◽  
Douglas A. Dawson
Keyword(s):  
Time Dependent ◽  
New Model ◽  
Combination Effects ◽  
New Models

A new model for combination effects gives descriptions of additivity, independence, synergy and antagonism and explains the multiple shapes of isoboles.

New Algorithm for Modeling of Bronchial Trees

2012 ◽  
Vol 17 (4) ◽  
pp. 179-190
Author(s):  
Kacper Pluta ◽  
Marcin Janaszewski ◽  
Michał Postolski
Keyword(s):  
Quantitative Analysis ◽  
3D Model ◽  
Ct Images ◽  
Basic Algorithm ◽  
New Model ◽  
Comparison Of Results ◽  
Basic Model ◽  
New Models ◽  
Bronchial Tubes

Abstract The article presents new conception of 3D model of human bronchial tubes, which represents bronchial tubes extracted from CT images of the chest. The new algorithm which generates new model is an extension of the algorithm (basic algorithm) proposed by Hiroko Kitaoka, Ryuji Takaki and Bela Suki. The basic model has been extended by geometric deformations of branches and noise which occur in bronchial trees extracted from CT images. The article presents comparison of results obtained with the use of the new algorithm and the basic one. Moreover, the discussion of usefulness of generated new models for testing of algorithms for quantitative analysis of bronchial tubes based on CT images is also included.

Application of a Viscoelastic Model for Polyester Mooring

2010 ◽  
Author(s):  
J. W. Kim ◽  
J. H. Kyoung ◽  
A. Sablok
Keyword(s):  
Material Properties ◽  
Viscoelastic Model ◽  
Practical Method ◽  
Time Dependent ◽  
Mooring Line ◽  
New Model ◽  
Global Performance ◽  
Excitation Period ◽  
Linear Viscoelastic ◽  
Floating Platforms

A new practical method to simulate time-dependent material properties of polyester mooring line is proposed. The time-dependent material properties of polyester rope are modeled with a standard linear solid (SLS) model, which is one of the simplest forms of a linear viscoelastic model. The viscoelastic model simulates most of the mechanical properties of polyester rope such as creep, strain-stress hysteresis and excitation period-dependent stiffness. The strain rate-stress relation of the SLS model has been re-formulated to a stretch-tension relation, which is more suitable for implementation into global performance and mooring analyses tools for floating platforms. The new model has been implemented to a time-domain global performance analysis software and applied to simulate motion of a spar platform with chain-polyester-chain mooring system. The new model provides accurate platform offset without any approximation on the mean environmental load and can simulate the transient effect due to the loss of a mooring line during storm conditions, which has not been possible to simulate using existing dual-stiffness models.

How Social Media Offers Opportunities for Growth in the Traditional Media Industry

2019 ◽  
pp. 727-742
Author(s):  
Andrew Duffy
Keyword(s):  
Social Media ◽  
Web 2.0 ◽  
Media Industry ◽  
Traditional Media ◽  
New Model ◽  
New Models

Under threat from social media and interactive Web 2.0, the traditional media industry seeks new models to maintain its viability. This chapter studies both consumers and prospective producers of one genre—travel journalism—to advocate a model that could help arrest the industry's decline and return to growth. It argues that one way forward for traditional media would be a new model of curatorship, in which a professional journalist collaborates with amateur contributors. It suggests that such a hybrid arrangement will be recognisable neither as professional newsroom nor as amateur social media, but a new model with features of both. This offers a way forward so that rather than contributing to the declining fortunes of the traditional media industry, as many journalists fear, social media can instead encourage progress.

ENTROPY OF A NONSTATIC BLACK HOLE

2000 ◽  
Vol 15 (28) ◽  
pp. 1739-1747 ◽  
Author(s):  
LI XIANG ◽  
ZHAO ZHENG
Keyword(s):  
Black Hole ◽  
Black Hole Entropy ◽  
Time Dependent ◽  
Brick Wall ◽  
Two Dimensional ◽  
De Sitter ◽  
Wall Model ◽  
New Model ◽  
Brick Wall Model ◽  
Dynamical Degrees

We point out that the brick-wall model cannot be applied to the nonstatic black hole. In the case of a static hole, we propose a new model where the black hole entropy is attributed to the dynamical degrees of the field covering the two-dimensional membrane just outside the horizon. A cutoff different from the model of 't Hooft is necessarily introduced. It can be treated as an increase in horizon because of the space–time fluctuations. We also apply our model to the nonequilibrium and nonstatic cases, such as Schwarzschild–de Sitter and Vaidya space–times. In the nonstatic case, the entropy relies on a time-dependent cutoff.

scholarly journals New line-blanketed model atmospheres and their impact on synthesis models

2003 ◽  
Vol 212 ◽  
pp. 604-611
Author(s):  
Linda J. Smith ◽  
Richard P.F. Norris ◽  
Paul A. Crowther
Keyword(s):  
Model Atmosphere ◽  
Evolutionary Synthesis ◽  
H Ii Regions ◽  
Single Star ◽  
New Model ◽  
New Models ◽  
Low Metallicity ◽  
H Ii Region ◽  
Basic Code ◽  
Photo Ionization

A new grid of ionizing fluxes for O-type and Wolf-Rayet stars is presented for use with evolutionary synthesis codes and analyses of single star H ii regions. A total of 230 expanding, non-LTE, line-blanketed model atmospheres have been calculated for five metallicities (0.05, 0.2, 0.4, 1 and 2 Z⊙). We have used the wm-basic code of Pauldrach et al. (2001) for O-type stars and the cmfgen code of Hillier & Miller (1998) for WR stars. The stellar wind parameters are scaled with metallicity for both O-type and WR stars. The ionizing fluxes of the new models, incorporated into the evolutionary synthesis code STARBURST99 (Leitherer et al. 1999), are compared with the predictions of the original starburst99 and Schaerer & Vacca (1998) for an instantaneous burst. We find large changes in the output ionizing fluxes as a function of age, especially below the He+ edge. In contrast to previous studies, nebular He ii λ4686 will be at, or just below, the detection limit in low metallicity starbursts during the WR phase. The new models have lower fluxes in the He i continuum for Z ≥ 0.4 Z⊙ and ages ≤ 7 Myr because of the increased line-blanketing. The accuracy of the new model atmosphere grid is tested by constructing photo-ionization models for an H ii region where the ionizing flux is provided by an instantaneous burst. The new models occupy the same region in nebular diagnostic diagrams as the observational data of Bresolin et al. (1999), particularly during the WR phase. The new model grid and updated starburst99 code can be downloaded from http://www.star.ucl.ac.uk/starburst.

Disturbing arithmetic

1985 ◽  
Vol 50 (2) ◽  
pp. 375-379 ◽  
Author(s):  
Thomas J. Grilliot
Keyword(s):  
Fine Structure ◽  
Prime Number ◽  
Long Range ◽  
Set Theory ◽  
New Model ◽  
New Models ◽  
Models Of Arithmetic ◽  
Two Alternatives

One long-range objective of logic is to find models of arithmetic with noteworthy properties, perhaps properties that imply some long-standing number theoretic conjectures. In areas of mathematics such as algebra or set theory, new models are often made by extending old models, that is, by adjoining new elements to already existing models. Usually the extension retains most of the characteristics of the old model with at least one exception that makes the new model interesting. However, such a scheme is difficult in the area of arithmetic. Many interesting properties of the fine structure of arithmetic are diophantine and hence unchangeable in extensions. For instance, one cannot change a prime number into a composite one by adjoining new elements.One could possibly get around this diophantine difficulty in one of two ways. One way is to change the usual language of addition and multiplication to an equivalent language that does not transmit so much information to extensions. For instance, multiplication is definable from the squaring function, as one sees from the identity 2xy = (x + y)2 − x2 − y2, and the squaring function in turn is definable either from the unary square predicate (as one sees from the fact that n = m2 if n and n + 2m + 1 are successive squares) or from the divisor relation (as one sees from the fact that n = m2 if n is the smallest number such that m divides n and m + 1 divides n + m). Either of these two alternatives to multiplication might make for interesting extensions.

8. Mover-Stayer Models for Analyzing Event Nonoccurrence and Event Timing with Time-Dependent Covariates: An Application to an Analysis of Remarriage

1998 ◽  
Vol 28 (1) ◽  
pp. 327-361 ◽  
Author(s):  
Kazuo Yamaguchi
Keyword(s):  
Black Women ◽  
White Women ◽  
Time Dependent ◽  
Regression Equations ◽  
New Model ◽  
American Women ◽  
Duration Data ◽  
Covariate Effects ◽  
Event Timing ◽  
Time Dependent Covariates

This paper introduces a novel extension of mover-stayer models for duration data that allows time-dependent covariates to be used for both a pair of regression equations, one that identifies the determinants of event timing and one that identifies the determinants of the probability of ultimate event nonoccurrence. Existing models intended to distinguish covariate effects on event timing from those on event nonoccurrence cannot use time-dependent covariates in the equation for the probability of ultimate event nonoccurrence. This paper applies the new model to an analysis of remarriage among American women. The analysis generally demonstrates that some covariates effect remarriage timing while others affect the probability of ultimate remarriage nonoccurrence. Some differences in patterns of remarriage between black women and white women are also reported. Theoretical implications of these findings are discussed.

A Regional Zenith Tropospheric Correction Model Based on the Guangxi CORS Network

2013 ◽  
Vol 353-356 ◽  
pp. 3438-3443
Author(s):  
Li Long Liu ◽  
Liang Ke Huang ◽  
Teng Xu Zhang ◽  
Miao Zhou ◽  
Chao Long Yao
Keyword(s):  
Interpolation Method ◽  
Meteorological Data ◽  
Correction Model ◽  
New Model ◽  
Model Based ◽  
Proposed Model ◽  
New Models ◽  
Using Data ◽  
The Relationship ◽  
Tropospheric Delays

In this paper, the relationship between zenith tropospheric delays and the altitude of stations is analyzed using the EGNOS tropospheric correction model. The new model (EHT model) is proposed for estimating zenith tropospheric delays from regional CORS data without meteorological data. The proposed model is compared with the direct interpolation method and the remove-restore method using data from Guangxi CORS. The results show that the new models significantly improve the calculated precision.

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