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- Ceciliason, Ann-Sofie, 1971-
(författare)
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Forensic taphonomy in an indoor setting : Implications for estimation of the post-mortem interval
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of this thesis was to determine if and how taphonomic data can be used to expand our knowledge concerning the decompositional process in an indoor setting, as well as adapting scoring-based methods for quantification of human decomposition, to increase the precision of post-mortem interval (PMI) estimates.In the first paper, the established methods of Total Body Score (TBS) and Accumulated Degree-Days (ADD) were investigated in an indoor setting, with results indicating a fairly low precision. The PMI was often underestimated in cases with desiccation and overestimated in cases with presence of insect activity. This suggests that the TBS method needs to be slightly modified to better reflect the indoor decompositional process.In the second paper, a novel method for PMI estimation was developed using histological assessment of decompositional changes in the human liver. The scoring-based method created, the Hepatic Decomposition Score, was a statistically robust way to quantify the degree of decomposition, with the potential to improve the precision of PMI estimates.In the third paper, the indoor decomposition process was further investigated regarding microbial neoformation of volatiles in relation to the degree of decomposition and the PMI. A higher decomposition degree was observed in cases with neoformation (i.e., presence of N-propanol and/or 1-butanol in femoral vein blood) than in cases without signs of neoformation. Microbial neoformation may be an indicator of decomposition rate, which may make it possible to improve the precision of PMI estimates based on the TBS/ADD method.In the fourth paper, a novel constructed Bayesian framework allowed a qualified estimate of PMI based on observed taphonomic findings. This framework provided a unique possibility to report results, express the uncertainties in assumptions and calculations, as well as to evaluate competing hypotheses regarding PMI periods or time of death.Taken as a whole, the results indicate that using taphonomic data derived from an indoor setting could improve scoring-based methods, as well as highlighting benefits of incorporating such data into a Bayesian framework for interpretational purposes and for reporting PMI estimates.
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| 2. |
- Ceciliason, Ann-Sofie, 1971-, et al.
(författare)
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Histological quantification of decomposed human livers : a potential aid for estimation of the post-mortem interval?
- 2021
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Ingår i: International journal of legal medicine. - : Springer Nature. - 0937-9827 .- 1437-1596. ; 135:1, s. 253-267
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to determine if a novel scoring-based model for histological quantification of decomposed human livers could improve the precision of post-mortem interval (PMI) estimation for bodies from an indoor setting. The hepatic decomposition score (HDS) system created consists of five liver scores (HDS markers): cell nuclei and cell structure of hepatocytes, bile ducts, portal triad, and architecture. A total of 236 forensic autopsy cases were divided into a training dataset (n = 158) and a validation dataset (n = 78). All cases were also scored using the total body score (TBS) method. We specified a stochastic relationship between the log-transformed accumulated degree-days (log10ADD) and the taphonomic findings, using a multivariate regression model to compute the likelihood function. Three models were applied, based on: (i) five HDS markers, (ii) three partial body scores (head, trunk, limbs), or (iii) a combination of the two. The predicted log10ADD was compared with the true log10ADD for each case. The fitted models performed equally well in the training dataset and the validation dataset. The model comprising both scoring methods had somewhat better precision than either method separately. Our results indicated that the HDS system was statistically robust. Combining the HDS markers with the partial body scores resulted in a better representation of the decomposition process and might improve PMI estimation of decomposed human remains.
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| 3. |
- Ceciliason, Ann-Sofie, 1971-, et al.
(författare)
-
Microbial neoformation of volatiles: implications for the estimation of post-mortem interval in decomposed human remains in an indoor setting
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this study was to determine if a relationship between microbial neoformation of volatiles and the post-mortem interval (PMI) exists, and if the volatiles could be used as a tool to improve the precision of PMI estimation in decomposed human remains found in an indoor setting. Chromatograms from alcohol analysis (femoral vein blood) of 412 cases were retrospectively assessed for presence of ethanol, N-propanol, 1-butanol, and acetaldehyde. The most common finding was acetaldehyde (83% of the cases), followed by ethanol (37%), N-propanol (21%) and 1-butanol (4%). A direct link between the volatiles and the PMI or the degree of decomposition was not observed. However, the decomposition had progressed faster in cases with microbial neoformation than in cases without signs of neoformation. Microbial neoformation may therefore act as an indicator of the decomposition rate within the early decomposition to bloating stages. This may be used in PMI estimation based on the total body score (TBS) and accumulated-degree days (ADD) model, to potentially improve the model’s precision.
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