scholarly journals THE COVID-19 PANDEMIC DOES NOT HAVE A DIFFUSION INDEX.

2021 ◽  
Vol 100 (08) ◽  
pp. 260-266
Author(s):  
S. U. Zhanatauov ◽  
Keyword(s):  
2021 ◽  
Vol 13 (11) ◽  
pp. 2124
Author(s):  
Kamila M. Harenda ◽  
Mateusz Samson ◽  
Radosław Juszczak ◽  
Krzysztof M. Markowicz ◽  
Iwona S. Stachlewska ◽  
...  

Peatlands play an important role in the global carbon cycle due to the high carbon storage in the substrate. Ecosystem production depends, for example, on the solar energy amount that reaches the vegetation, however the diffuse component of this flux can substantially increase ecosystem net productivity. This phenomenon is observed in different ecosystems, but the study of the atmosphere optical properties on peatland production is lacking. In this paper, the presented methodology allowed us to disentangle the diffuse radiation impact on the net ecosystem production (NEP) of Rzecin peatland, Poland. It allowed us to assess the impact of the atmospheric scattering process determined by the aerosol presence in the air mass. An application of atmospheric radiation transfer (ART) and ecosystem production (EP) models showed that the increase of aerosol optical thickness from 0.09 to 0.17 caused NEP to rise by 3.4–5.7%. An increase of the diffusion index (DI) by 0.1 resulted in an NEP increase of 6.1–42.3%, while a DI decrease of 0.1 determined an NEP reduction of −49.0 to −10.5%. These results show that low peatland vegetation responds to changes in light scattering. This phenomenon should be taken into account when calculating the global CO2 uptake estimation of such ecosystems.


1961 ◽  
Vol 43 (2) ◽  
pp. 201 ◽  
Author(s):  
H. O. Stekler
Keyword(s):  

2018 ◽  
Vol 17 (2) ◽  
pp. 259-279 ◽  
Author(s):  
Abdelmonem Oueslati ◽  
Yacine Hammami

Purpose This paper aims to investigate the performance of various return forecasting variables and methods in Saudi Arabia and Malaysia. The authors document that market excess returns in Saudi Arabia are predicted by changes in oil prices, the dividend yield and inflation, whereas the equity premium in Malaysia is predicted only by the US market excess returns. In both countries, the authors find that the diffusion index is the best forecasting method and stock return predictability is stronger in expansions than in recessions. To interpret the findings, the authors perform two tests. The empirical results suggest irrational pricing in Malaysia and rationally time-varying expected returns in Saudi Arabia. Design/methodology/approach The authors apply the state-of-the-art in-sample and out-of-sample forecasting techniques to predict stock returns in Saudi Arabia and Malaysia. Findings The Saudi equity premium is predicted by oil prices, dividend yield and inflation. The Malaysian equity premium is predicted by the US market excess returns. In both countries, the authors find that the diffusion index is the best forecasting method. In both countries, predictability is stronger in expansions than in recessions. The tests suggest irrational pricing in Malaysia and rationality in Saudi Arabia. Practical implications The empirical results have some practical implications. The fact that stock returns are predictable in Saudi Arabia makes it possible for policymakers to better evaluate future business conditions, and thus to take appropriate decisions regarding economic and monetary policy. In Malaysia, the results of this study have interesting implications for portfolio management. The fact that the Malaysian market seems to be inefficient suggests the presence of strong opportunities for sophisticated investors, such as hedge and mutual funds. Originality/value First, there are no papers that have studied the return predictability in Saudi Arabia in spite of its importance as an emerging market. Second, the methods that combine all predictive variables such as the diffusion index or the kitchen sink methods have not been implemented in emerging markets. Third, this paper is the first study to deal with time-varying short-horizon predictability in emerging countries.


PLoS ONE ◽  
2013 ◽  
Vol 8 (3) ◽  
pp. e57768 ◽  
Author(s):  
Christopher H. Chapman ◽  
Mohammad Nazem-Zadeh ◽  
Oliver E. Lee ◽  
Matthew J. Schipper ◽  
Christina I. Tsien ◽  
...  

2012 ◽  
Vol 512-515 ◽  
pp. 1823-1832
Author(s):  
Ru Feng Xiao ◽  
Jing Yang Liu ◽  
Jian Qiang Zhang

In order to understand the mass transfer process of water molecules in the reverse osmosis membrane based on the dynamic adsorption theory and diffusion transfer concept, according to the theory of random walk, the diffusion-adsorption equation is deduced at the beginning of dynamic adsorption around all diffusion regions. It was studied and analyzed the dynamic adsorption behaviour of H2O in reverse osmosis membrane of polyamide in the experiment, and the influence of the different temperature to the dynamic adsorption of the reverse osmosis membrane on the early stages was discussed, and calculated the abnormal diffusion index dw. The results showed that the water molecules in this aromatic polyamide type reverse osmosis membrane have the behaviour of abnormal dynamic adsorption, and the higher temperature was, the smaller the abnormal diffusion index dw was.


2017 ◽  
Vol 4 ◽  
pp. 84-88 ◽  
Author(s):  
Zengai Chen ◽  
Jinyan Zu ◽  
Lei li ◽  
Xiaojie Lu ◽  
Jianming Ni ◽  
...  

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