Hedging of Defaultable Contingent Claims using BSDE with uncertain time horizon

This article focuses on the mathematical problem of existence and uniqueness of BSDE with a random terminal time which is a general random variable but not a stopping time, as it has been usually the case in the previous literature of BSDE with random terminal time. The main motivation of this work is a financial or actuarial problem of hedging of defaultable contingent claims or life insurance contracts, for which the terminal time is a default time or a death time, which are not stopping times. We have to use progressive enlargement of the Brownian filtration, and to solve the obtained BSDE under this enlarged filtration. This work gives a solution to the mathematical problem and proves the existence and uniqueness of solutions of such BSDE under certain general conditions. This approach is applied to the financial problem of hedging of defaultable contingent claims, and an expression of the hedging strategy is given for a defaultable contingent claim or a life insurance contract

Hedging of Defaultable Contingent Claims using BSDE with uncertain time horizon.

This article focuses on the mathematical problem of existence and uniqueness of BSDE with a random terminal time which is a general random variable but not a stopping time, as it has been usually the case in the previous literature of BSDE with random terminal time. The main motivation of this work is a financial or actuarial problem of hedging of defaultable contingent claims or life insurance contracts, for which the terminal time is a default time or a death time, which are not stopping times. We have to use progressive enlargement of the Brownian filtration, and to solve the obtained BSDE under this enlarged filtration. This work gives a solution to the mathematical problem and proves the existence and uniqueness of solutions of such BSDE under certain general conditions. This approach is applied to the financial problem of hedging of defaultable contingent claims, and an expression of the hedging strategy is given for a defaultable contingent claim or a life insurance contract.

Animal welfare: review of the scientific concept and definition

The aim of this paper is to present a review of the current scientific viewpoints about the concept and definition of animal welfare. The need of interaction among different disciplines is stressed, as well as the need to scientifically assess welfare, using validated indicators. The role of applied ethology in animal welfare science is stressed. The paper provides a brief overview of the historical steps in the development of the concept and presents scientific viewpoints, briefly explaining their theoretical foundation. The possibility of defining welfare on a scientific basis is explained, identifying the main problems according to the scientific, cultural and social background. Another aspect considered is the relationship between welfare and ethics, evidencing the meaning of such an interaction and its possible evolution

Massive comparative genomic analysis reveals convergent evolution of specialized bacteria

<p>Abstract</p> <p>Background</p> <p>Genome size and gene content in bacteria are associated with their lifestyles. Obligate intracellular bacteria (i.e., mutualists and parasites) have small genomes that derived from larger free-living bacterial ancestors; however, the different steps of bacterial specialization from free-living to intracellular lifestyle have not been studied comprehensively. The growing number of available sequenced genomes makes it possible to perform a statistical comparative analysis of 317 genomes from bacteria with different lifestyles.</p> <p>Results</p> <p>Compared to free-living bacteria, host-dependent bacteria exhibit fewer rRNA genes, more split rRNA operons and fewer transcriptional regulators, linked to slower growth rates. We found a function-dependent and non-random loss of the same 100 orthologous genes in all obligate intracellular bacteria. Thus, we showed that obligate intracellular bacteria from different phyla are converging according to their lifestyle. Their specialization is an irreversible phenomenon characterized by translation modification and massive gene loss, including the loss of transcriptional regulators. Although both mutualists and parasites converge by genome reduction, these obligate intracellular bacteria have lost distinct sets of genes in the context of their specific host associations: mutualists have significantly more genes that enable nutrient provisioning whereas parasites have genes that encode Types II, IV, and VI secretion pathways.</p> <p>Conclusion</p> <p>Our findings suggest that gene loss, rather than acquisition of virulence factors, has been a driving force in the adaptation of parasites to eukaryotic cells. This comparative genomic analysis helps to explore the strategies by which obligate intracellular genomes specialize to particular host-associations and contributes to advance our knowledge about the mechanisms of bacterial evolution.</p> <p>Reviewers</p> <p>This article was reviewed by Eugene V. Koonin, Nicolas Galtier, and Jeremy Selengut.</p

Lipid Metabolism and Cardiovascular Risk in HIV-1 Infection and HAART: Present and Future Problems

Many infections favor or are directly implicated with lipid metabolism perturbations and/or increased risk of coronary heart disease (CHD). HIV itself has been shown to increase lipogenesis in the liver and to alter the lipid profile, while the presence of unsafe habits, addiction, comorbidities, and AIDS-related diseases increases substantially the risk of cardiovascular disease (CVD) in the HIV-infected population. Antiretroviral therapy reduces such stimuli but many drugs have intrinsic toxicity profiles impacting on metabolism or potential direct cardiotoxicity. In a moment when the main guidelines of HIV therapy are predating the point when to start treating, we mean to highlight the contribution of HIV-1 to lipid alteration and inflammation, the impact of antiretroviral therapy, the decisions on what drugs to use to reduce the probability of having a cardiovascular event, the increasing use of statins and fibrates in HIV-1 infected subjects, and finally the switch strategies, that balance effectiveness and toxicity to move the decision to change HIV drugs. Early treatment might reduce the negative effect of HIV on overall cardiovascular risk but may also evidence the impact of drugs, and the final balance (reduction or increase in CHD and lipid abnormalities) is not known up to date

Evaluation of skin temperature change as stress indicator in rabbit through infrared thermography

AbstractStress-induced reactions in animals include behavioural and physiological modifications aiming at coping towards the stressor, such as manipulations. Thermography, that is the detection of ..

Survey on housing, management and welfare of dairy cattle in tie-stalls in western Italian Alps

In the Alps, the traditional breeding system for dairy cattle is based on the alternation between a free ranging period on mountain ranges during the summer, and an indoor period in tie-stalls in the cold season. Several welfare issues may arise in tie-stall housing systems. We described the situation in 47 farms in three villages in Western Italy, trying to identify possible relationships among structural and management characteristics, animal health and behaviour traits. A long duration of the grazing periods, associated with frequent manure removal during the housing period, are probably key factors for limiting the occurrence of lameness. Teat trauma are more common in narrower stalls. Getting up behaviour is unnatural in most of the visited farms. Some lacks in the farmers' knowledge of animal behaviour was pointed out. Some structural and management characteristics are strictly related to geographic constraints. However, situation permitting, some expedients may be achieved for improving welfare levels

Exploring the Depths of the Autocorrelation Function: Its Departure from Normality

In this article, we study the autocorrelation function (ACF), which is a crucial element in time series analysis. We compare the distribution of the ACF, both from a theoretical and empirical point of view. We focus on white noise processes (WN), i.e., uncorrelated, centered, and identically distributed variables, whose ACFs are supposed to be asymptotically independent and converge towards the same normal distribution. But, the study of the sum of the sample ACF contradicts this property. Thus, our findings reveal a deviation of the sample ACF from normality beyond a specific lag. Note that this phenomenon is observed for white noise of varying lengths, and evenforn the residuals of an ARMA