69 research outputs found

    Post-mortem volatiles of vertebrate tissue

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    Volatile emission during vertebrate decay is a complex process that is understood incompletely. It depends on many factors. The main factor is the metabolism of the microbial species present inside and on the vertebrate. In this review, we combine the results from studies on volatile organic compounds (VOCs) detected during this decay process and those on the biochemical formation of VOCs in order to improve our understanding of the decay process. Micro-organisms are the main producers of VOCs, which are by- or end-products of microbial metabolism. Many microbes are already present inside and on a vertebrate, and these can initiate microbial decay. In addition, micro-organisms from the environment colonize the cadaver. The composition of microbial communities is complex, and communities of different species interact with each other in succession. In comparison to the complexity of the decay process, the resulting volatile pattern does show some consistency. Therefore, the possibility of an existence of a time-dependent core volatile pattern, which could be used for applications in areas such as forensics or food science, is discussed. Possible microbial interactions that might alter the process of decay are highlighted

    Tests of fundamental symmetries with beta decay

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    Since the fall of parity in electroweak interactions the discrete transformations of parity, charge conjugation and time reversal are under close scrutiny for any sign of deviation from maximality where symmetry breaking seems to be complete (like P violation in beta decay) and for any sign of symmetry breaking when this has not yet been observed (like T violation in beta decay). The Standard Model (SM) of electroweak interactions remains robust in explaining the outcome of all experiments with beta rays. Bounds set by P- and T-reversal tests are tightening but remain stubbornly within the SM. However, the solar-neutrino issue enters the era beyond the SM by requiring upsilon oscillations and a non-zero upsilon mass. This review emphasizes experiments with beta rays, but includes solar-neutrino and beta beta-decay findings and devotes some attention to the broken symmetry in biochirality. Theoretical descriptions attempt to implement the symmetry breaking in a causal way, pointing to a possible earlier manifest left-right symmetry, and stimulating searches for deviations from the above maximality as a 'fossil' remnant of symmetry at a deeper level
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