Lake Urmia, the second largest hyper-saline lake on earth, has recently experienced a dramatic water level reduction. This could have been caused by climate change or other anthropogenic effects; however it could also be a part of natural climate variability. To explore the hydroclimate variability effect on the lake water level, two tele-connections were considered for analyses; Southern Oscillation Index (SOI) and Northern Atlantic Oscillation (NAO). Spectral and coherency analysis were used to recognize the frequency components and relationship between the teleconnections and the lake water level fluctuations. The results show that the recent water level fall and the rise of water level in 1994-1999 cannot be explained by natural periodic behavior of Lake Urmia. The inter-decadal water level oscillations are coherent with NAO and SOI components of such oscillations. The anthropogenic effect on the lake water level was also explored using non-parametric trend analysis. The results show that the lake water level has a positive trend between 1966 and 1995, but the trend is not significant at a 95% confidence level.On the other hand, the trend between 1995 and 2009 is negative and it is significant at a 99% confidence interval. This study shows that the very recent water level fall is due to anthropogenic impacts rather than natural variability.
We present an experimental investigation of the diffusion of unfolded polymers in the triply-periodic water-channel network of inverse bicontinuous cubic phases. Depending on the chain size, our results indicate the presence of two different dynamical regimes corresponding to Zimm and Rouse diffusion. We support our findings by scaling arguments based on a combination of blob and effective-medium theories and suggest the presence of a third regime where dynamics is driven by reptation. Our experimental results also show an increasing behavior of the partition coefficient as a function of the polymer molecular weight, indicative of a reduction in the conformational degrees of freedom induced by the confinement.
Lipid self-assembled structures (SASs) have recently gained considerable interest for their potential applications, especially for sustained nutrient release and protein crystallization. An additional property, which is underexploited, is their ability to control chemical reactions in food products. Here, we concentrate on SASs formed by phospholipids (PLs) and monoglycerides (MGs), those compounds being the most natural surfactants and therefore, the best compatible with food products, in view of providing new functionalities through the formation of SASs. In this work, the phase behaviour of these amphiphiles when mixed with oil and water is described and compared. Subsequently, we address the influence of these structures to the oxidation and Maillard-type reactions. Finally, we show that SASs formed by MGs can strongly increase the yield of key aroma impact compounds generated by Maillard-type reactions when compared with the reaction performed in aqueous precursor solutions. Various SASs are compared. In particular, addition of oil to a reversed bicontinuous structure formed by MG leads to a reversed microemulsion, which, considering its low viscosity, is particularly suitable for food products and act as a very efficient reactor system. The influence of oil and precursors on phase behaviour is discussed and related to the efficiency of the Maillard reactions.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.
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