Cap Impact on Rural Households Livelihood Strategies in Bulgaria

Agricultural and Food Policy, Consumer/Household Economics,

Melatonin attenuates oxidative stress and modulates inflammatory response after experimental burn trauma

Introduction. Thermal injury activates an inflammatory response. Melatonin possesses anti-oxidant and anti-inflammatory properties. The objective of the present work was to study melatonin effects on the inflammatory response under conditions of oxidative stress during the early stage of thermal injury. Materials and methods. We used 24 white male rats of Wistar breed, randomly divided into three experimental groups. Group one was the control, group two was inflicted with burn trauma, and group three was inflicted with burn trauma, with melatonin application following the thermal injury. Melatonin was applied twice in doses of 10 g/kg b.m. immediately after the burn trauma and again at 12 hours. Plasma levels of tumor necrosis-factor-α (TNF-α), a pro-inflammatory mediator, and of interleukin-10 (Il-10), an anti-inflammatory mediator, were examined and their ratio was calculated. The levels of malondialdehyde (MDA), an oxidative stress marker, were also estimated. Results. Thermal trauma significantly increased plasma TNF-α levels (ð\u3c0.01) and TNF-α /IL-10 ratio but did not change IL-10 ones. Plasma MDA concentrations were significantly elevated as well (ð\u3c0.0001). Melatonin application significantly reduced TNF-α (ð\u3c0.05), increased IL-10 (ð\u3c0.05), down-regulated TNF-α/IL-10 ratio and changed MDA concentrations (ð\u3c0.01). In conclusion, our results show that local alteration induces oxidative stress and inflammatory response with TNF-α /IL-10 disbalance. Melatonin modulates this response and attenuates oxidative stress in experimental burn injury

Approximating Probability Densities by Iterated Laplace Approximations

The Laplace approximation is an old, but frequently used method to approximate integrals for Bayesian calculations. In this paper we develop an extension of the Laplace approximation, by applying it iteratively to the residual, i.e., the difference between the current approximation and the true function. The final approximation is thus a linear combination of multivariate normal densities, where the coefficients are chosen to achieve a good fit to the target distribution. We illustrate on real and artificial examples that the proposed procedure is a computationally efficient alternative to current approaches for approximation of multivariate probability densities. The R-package iterLap implementing the methods described in this article is available from the CRAN servers.Comment: to appear in Journal of Computational and Graphical Statistics, http://pubs.amstat.org/loi/jcg

Stress-associated changes in the gut microbiome of Asian elephants

Background: The intestinal tract of practically all animals is inhabited by a diverse microorganism referred to as gut microbiome. The importance of gut microbiome to its host is well known and an increasing number of studies show that the microbes are associated with many body functions, such as the gut-brain axis function. Stress, in particular, can impact the gut-brain axis at all stages of life. Stress can reshape the gut bacterial composition through glucocorticoid secretion, inflammation, or autonomic alterations. This often leads to gut bacterial imbalance (dysbiosis), as well as low microbial diversity. Although studies on gut microbiome are increasing, the mechanisms of gut-brain axis and how microbes associate with stress still remain poorly understood. Also, the gut microbiome studies have focused mostly on humans or laboratory animals in controlled environments. It is important to widen the studies on mammals in their natural environment to better understand the complex development of gut microbiome. The aim of this thesis was to (1) determine the composition of gut microbiome of Asian elephants living in their natural environment and (2) test the hypothesis that increased stress alters the gut microbiome composition. Methods: The gut microbiome was determined from 94 semi-captive Asian elephants (Elephas maximus) in Myanmar, from which both fecal sample collection and blood sampling was possible. The gut microbiome was analyzed from the fecal samples using 16S rRNA metabarcoding approach. Stress levels were determined from the blood samples as: (I) serum cortisol (SC), (II) heterophil to lymphocyte ratio in blood samples (H:L) and (III) fecal glucocorticoid metabolites (FGM). Results: The overall gut microbe composition in Asian elephants was similar to previous studies, dominated by Firmicutes (55%) and Bacteroidetes (25%) followed by Spirochaetaes (8%). One specific genus Solibacillus was found to be significantly more abundant in this thesis compared to previous studies. There were also differences in the microbiome between elephants. The age and location of the elephant had significant effects on the gut microbe composition. The stress measure H:L ratio was also associated with gut microbiome by reducing the alpha diversity. All three stress measures were also associated with compositional changes in the gut microbiome. Conclusions: Gut microbe composition in Asian elephants is diverse and similar to other fermenters. Stress, particularly long-term stress, can shape the composition of the microbiome. This thesis provides in my knowledge the most comprehensive picture of gut microbiome in Asian elephants in their natural living environment. In addition, this thesis adds important knowledge of the microbiota-gut-brain axis and how stress levels are associated with it

Incentivizing participation in ambitious international climate policy

The climate club model has been proposed as an alternative approach to international climate change mitigation policy. Unlike the unilateral negotiations organized under the United Nations climate convention, a climate club would be comprised of countries that commit to ambitious emissions reductions and provide incentives to encourage cooperation and deter free-riding. In this thesis, I conduct a literature review to examine the potential of the climate club approach, intending to discover whether a club mechanism could produce an effective agreement that the UN approach has failed to achieve. The findings from microeconomic theory and simulation models indicate that a climate club might indeed achieve broad participation and significant abatement levels. Of the possible incentive configurations, both side-payments, sanctions, and a combination of club goods and conditional commitments are shown to be effective options. While the theoretical potential of the climate club approach appears high, its implementation would likely be complicated by legal and political barriers. The club design would therefore need to account not only for effectiveness but also for political feasibility