Influence of cosmological expansion on the threshold effects in the annihilation reaction of hard photons with CMB photons

2005 ◽  
Vol 31 (1) ◽  
pp. 1-6
Author(s):  
Yu. S. Grishkan ◽  
A. A. Pershin
Keyword(s):  
Threshold Effects ◽  
Cosmological Expansion ◽  
Annihilation Reaction

Is More Invariably Better?: Threshold Effects of Firefighters' Social Support

2007 ◽  
Author(s):  
Monique M. Mendoza ◽  
Jennifer K. Shannon ◽  
Shiloh E. Jordan ◽  
Yuhong He ◽  
David Tager ◽  
...  
Keyword(s):  
Social Support ◽  
Threshold Effects

scholarly journals Constraining the Swiss-Cheese IR-Fixed Point Cosmology with Cosmic Expansion

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 263
Author(s):  
Ayan Mitra ◽  
Vasilios Zarikas ◽  
Alfio Bonanno ◽  
Michael Good ◽  
Ertan Güdekli
Keyword(s):  
Fixed Point ◽  
Cosmological Constant ◽  
Cosmic Acceleration ◽  
Fine Tuning ◽  
Clusters Of Galaxies ◽  
Swiss Cheese ◽  
Coincidence Problem ◽  
Cosmological Expansion ◽  
Cosmic Evolution ◽  
Previous Assumption

A recent work proposed that the recent cosmic passage to a cosmic acceleration era is the result of the existence of small anti-gravity sources in each galaxy and clusters of galaxies. In particular, a Swiss-cheese cosmology model, which relativistically integrates the contribution of all these anti-gravity sources on a galactic scale has been constructed assuming the presence of an infrared fixed point for a scale dependent cosmological constant. The derived cosmological expansion provides an explanation for both the fine tuning and the coincidence problem. The present work relaxes the previous assumption on the running of the cosmological constant and allows for a generic scaling around the infrared fixed point. Our analysis reveals that, in order to produce a cosmic evolution consistent with the best ΛCDM model, the IR-running of the cosmological constant is consistent with the presence of an IR-fixed point.

Evaluating Threshold Effects in Consumer Sentiment

2004 ◽  
Vol 70 (4) ◽  
pp. 942-952
Author(s):  
Brigitte Desroches ◽  
Marc‐André Gosselin
Keyword(s):  
Threshold Effects ◽  
Consumer Sentiment

scholarly journals Threshold Effects of Infectious Disease Outbreaks on Livestock Prices: Cases of African Swine Fever and Avian Influenza in South Korea

2021 ◽  
Vol 11 (11) ◽  
pp. 5114
Author(s):  
Hyung-Chul Rah ◽  
Hyeon-Woong Kim ◽  
Aziz Nasridinov ◽  
Wan-Sup Cho ◽  
Seo-Hwa Choi ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Infectious Diseases ◽  
Disease Outbreaks ◽  
African Swine Fever ◽  
Threshold Effect ◽  
Impact Response ◽  
Threshold Effects ◽  
Infectious Disease Outbreaks ◽  
Retail Prices ◽  
The Impact

In this paper we demonstrate the threshold effects of infectious diseases on livestock prices. Daily retail prices of pork and chicken were used as structured data; news and SNS mentions of African Swine Fever (ASF) and Avian Influenza (AI) were used as unstructured data. Models were tested for the threshold effects of disease-related news and SNS frequencies, specifically those related to ASF and AI, on the retail prices of pork and chicken, respectively. The effects were found to exist, and the values of ASF-related news on pork prices were estimated to be −9 and 8, indicating that the threshold autoregressive (TAR) model can be divided into three regimes. The coefficients of the ASF-related SNS frequencies on pork prices were 1.1666, 0.2663 and −0.1035 for regimes 1, 2 and 3, respectively, suggesting that pork prices increased by 1.1666 Korean won in regime 1 when ASF-related SNS frequencies increased. To promote pork consumption by SNS posts, the required SNS frequencies were estimated to have impacts as great as one standard deviation in the pork price. These values were 247.057, 1309.158 and 2817.266 for regimes 1, 2 and 3, respectively. The impact response periods for pork prices were estimated to last 48, 6, and 8 days for regimes 1, 2 and 3, respectively. When the prediction accuracies of the TAR and autoregressive (AR) models with regard to pork prices were compared for the root mean square error, the prediction accuracy of the TAR model was found to be slightly better than that of the AR. When the threshold effect of AI-related news on chicken prices was tested, a linear relationship appeared without a threshold effect. These findings suggest that when infectious diseases such as ASF occur for the first time, the impact on livestock prices is significant, as indicated by the threshold effect and the long impact response period. Our findings also suggest that the impact on livestock prices is not remarkable when infectious diseases occur multiple times, as in the case of AI. To date, this study is the first to suggest the use of SNS to promote meat consumption.

scholarly journals Does the Cosmological Expansion Change Local Dynamics?

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1417
Author(s):  
Marcelo Schiffer
Keyword(s):  
Dark Matter ◽  
Modified Gravity ◽  
Hubble Constant ◽  
Matter Content ◽  
Matter Distribution ◽  
Present Value ◽  
Field Equations ◽  
Local Dynamics ◽  
Cosmological Expansion ◽  
Modified Gravity Theories

It is a well-known fact that the Newtonian description of dynamics within Galaxies for its known matter content is in disagreement with the observations as the acceleration approaches a0≈1.2×10−10 m/s2 (slighter larger for clusters). Both the Dark Matter scenario and Modified Gravity Theories (MGT) fail to explain the existence of such an acceleration scale. Motivated by the closeness of the acceleration scale and the Hubble constant cH0≈10−9 h m/s2, we are led to analyze whether this coincidence might have a Cosmological origin for scalar-tensor and spinor-tensor theories by performing detailed calculations for perturbations that represent the local matter distribution on the top of the cosmological background. Then, we solve the field equations for these perturbations in a power series in the present value of the Hubble constant. As we shall see, for both theories, the power expansion contains only even powers in the Hubble constant, a fact that renders the cosmological expansion irrelevant for the local dynamics.

scholarly journals Aspects of cosmological expansion inF(R) gravity models

2008 ◽  
Vol 2008 (05) ◽  
pp. 019 ◽  
Author(s):  
Stephen A Appleby ◽  
Richard A Battye
Keyword(s):  
Gravity Models ◽  
Cosmological Expansion
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