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Effect of body mass and clothing on decomposition of pig carcasses.

Matuszewski S, Konwerski S, Frątczak K, Szafałowicz M - Int. J. Legal Med. (2014)

Bottom Line: Unfortunately, effects of carcass mass and clothing on specific processes in decomposition and related entomological phenomena are unclear.In this article, simultaneous effects of these factors are analysed.In a range of low mass decomposition rate increased with an increase in mass, then at about 30 kg, there was a distinct decrease in rate, and again at about 50 kg, the rate slightly increased.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Criminalistics, Adam Mickiewicz University, Św. Marcin 90, 61-809, Poznań, Poland, szymmat@amu.edu.pl.

ABSTRACT
Carcass mass and carcass clothing are factors of potential high forensic importance. In casework, corpses differ in mass and kind or extent of clothing; hence, a question arises whether methods for post-mortem interval estimation should take these differences into account. Unfortunately, effects of carcass mass and clothing on specific processes in decomposition and related entomological phenomena are unclear. In this article, simultaneous effects of these factors are analysed. The experiment followed a complete factorial block design with four levels of carcass mass (small carcasses 5-15 kg, medium carcasses 15.1-30 kg, medium/large carcasses 35-50 kg, large carcasses 55-70 kg) and two levels of carcass clothing (clothed and unclothed). Pig carcasses (N = 24) were grouped into three blocks, which were separated in time. Generally, carcass mass revealed significant and frequently large effects in almost all analyses, whereas carcass clothing had only minor influence on some phenomena related to the advanced decay. Carcass mass differently affected particular gross processes in decomposition. Putrefaction was more efficient in larger carcasses, which manifested itself through earlier onset and longer duration of bloating. On the other hand, active decay was less efficient in these carcasses, with relatively low average rate, resulting in slower mass loss and later onset of advanced decay. The average rate of active decay showed a significant, logarithmic increase with an increase in carcass mass, but only in these carcasses on which active decay was driven solely by larval blowflies. If a blowfly-driven active decay was followed by active decay driven by larval Necrodes littoralis (Coleoptera: Silphidae), which was regularly found in medium/large and large carcasses, the average rate showed only a slight and insignificant increase with an increase in carcass mass. These results indicate that lower efficiency of active decay in larger carcasses is a consequence of a multi-guild and competition-related pattern of this process. Pattern of mass loss in large and medium/large carcasses was not sigmoidal, but rather exponential. The overall rate of decomposition was strongly, but not linearly, related to carcass mass. In a range of low mass decomposition rate increased with an increase in mass, then at about 30 kg, there was a distinct decrease in rate, and again at about 50 kg, the rate slightly increased. Until about 100 accumulated degree-days larger carcasses gained higher total body scores than smaller carcasses. Afterwards, the pattern was reversed; moreover, differences between classes of carcasses enlarged with the progress of decomposition. In conclusion, current results demonstrate that cadaver mass is a factor of key importance for decomposition, and as such, it should be taken into account by decomposition-related methods for post-mortem interval estimation.

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Related in: MedlinePlus

Carcass mass loss during decomposition of clothed and unclothed pig carcasses of different mass. The locally weighted method for scatter plot smoothing was used. Small carcasses 5–15 kg, medium carcasses 15.1–30 kg, medium/large carcasses 35–50 kg and large carcasses 55–70 kg. Solid line indicates unclothed carcasses, while broken line represents clothed carcasses
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Fig12: Carcass mass loss during decomposition of clothed and unclothed pig carcasses of different mass. The locally weighted method for scatter plot smoothing was used. Small carcasses 5–15 kg, medium carcasses 15.1–30 kg, medium/large carcasses 35–50 kg and large carcasses 55–70 kg. Solid line indicates unclothed carcasses, while broken line represents clothed carcasses

Mentions: Classes of carcasses differed according to the pattern of mass loss (Fig. 12). Small and medium carcasses revealed a typical sigmoidal pattern, with an initial no-change phase, followed by a rapid decrease in mass and a final no-change phase with carcass mass stabilizing at about 20 % of its initial mass (Fig. 12). In the case of medium/large and large carcasses, there was a constant and slow decrease in mass, followed by the final no-change phase with no sigmoidal shape of the curve and carcass mass stabilization at about 20–40 % of its initial mass (Fig. 12). Moreover, the decrease in mass was slightly slower for clothed carcasses as compared to unclothed carcasses (with the exception of small carcasses for which the pattern was reversed) (Fig. 12).Fig. 12


Effect of body mass and clothing on decomposition of pig carcasses.

Matuszewski S, Konwerski S, Frątczak K, Szafałowicz M - Int. J. Legal Med. (2014)

Carcass mass loss during decomposition of clothed and unclothed pig carcasses of different mass. The locally weighted method for scatter plot smoothing was used. Small carcasses 5–15 kg, medium carcasses 15.1–30 kg, medium/large carcasses 35–50 kg and large carcasses 55–70 kg. Solid line indicates unclothed carcasses, while broken line represents clothed carcasses
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4196037&req=5

Fig12: Carcass mass loss during decomposition of clothed and unclothed pig carcasses of different mass. The locally weighted method for scatter plot smoothing was used. Small carcasses 5–15 kg, medium carcasses 15.1–30 kg, medium/large carcasses 35–50 kg and large carcasses 55–70 kg. Solid line indicates unclothed carcasses, while broken line represents clothed carcasses
Mentions: Classes of carcasses differed according to the pattern of mass loss (Fig. 12). Small and medium carcasses revealed a typical sigmoidal pattern, with an initial no-change phase, followed by a rapid decrease in mass and a final no-change phase with carcass mass stabilizing at about 20 % of its initial mass (Fig. 12). In the case of medium/large and large carcasses, there was a constant and slow decrease in mass, followed by the final no-change phase with no sigmoidal shape of the curve and carcass mass stabilization at about 20–40 % of its initial mass (Fig. 12). Moreover, the decrease in mass was slightly slower for clothed carcasses as compared to unclothed carcasses (with the exception of small carcasses for which the pattern was reversed) (Fig. 12).Fig. 12

Bottom Line: Unfortunately, effects of carcass mass and clothing on specific processes in decomposition and related entomological phenomena are unclear.In this article, simultaneous effects of these factors are analysed.In a range of low mass decomposition rate increased with an increase in mass, then at about 30 kg, there was a distinct decrease in rate, and again at about 50 kg, the rate slightly increased.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Criminalistics, Adam Mickiewicz University, Św. Marcin 90, 61-809, Poznań, Poland, szymmat@amu.edu.pl.

ABSTRACT
Carcass mass and carcass clothing are factors of potential high forensic importance. In casework, corpses differ in mass and kind or extent of clothing; hence, a question arises whether methods for post-mortem interval estimation should take these differences into account. Unfortunately, effects of carcass mass and clothing on specific processes in decomposition and related entomological phenomena are unclear. In this article, simultaneous effects of these factors are analysed. The experiment followed a complete factorial block design with four levels of carcass mass (small carcasses 5-15 kg, medium carcasses 15.1-30 kg, medium/large carcasses 35-50 kg, large carcasses 55-70 kg) and two levels of carcass clothing (clothed and unclothed). Pig carcasses (N = 24) were grouped into three blocks, which were separated in time. Generally, carcass mass revealed significant and frequently large effects in almost all analyses, whereas carcass clothing had only minor influence on some phenomena related to the advanced decay. Carcass mass differently affected particular gross processes in decomposition. Putrefaction was more efficient in larger carcasses, which manifested itself through earlier onset and longer duration of bloating. On the other hand, active decay was less efficient in these carcasses, with relatively low average rate, resulting in slower mass loss and later onset of advanced decay. The average rate of active decay showed a significant, logarithmic increase with an increase in carcass mass, but only in these carcasses on which active decay was driven solely by larval blowflies. If a blowfly-driven active decay was followed by active decay driven by larval Necrodes littoralis (Coleoptera: Silphidae), which was regularly found in medium/large and large carcasses, the average rate showed only a slight and insignificant increase with an increase in carcass mass. These results indicate that lower efficiency of active decay in larger carcasses is a consequence of a multi-guild and competition-related pattern of this process. Pattern of mass loss in large and medium/large carcasses was not sigmoidal, but rather exponential. The overall rate of decomposition was strongly, but not linearly, related to carcass mass. In a range of low mass decomposition rate increased with an increase in mass, then at about 30 kg, there was a distinct decrease in rate, and again at about 50 kg, the rate slightly increased. Until about 100 accumulated degree-days larger carcasses gained higher total body scores than smaller carcasses. Afterwards, the pattern was reversed; moreover, differences between classes of carcasses enlarged with the progress of decomposition. In conclusion, current results demonstrate that cadaver mass is a factor of key importance for decomposition, and as such, it should be taken into account by decomposition-related methods for post-mortem interval estimation.

Show MeSH
Related in: MedlinePlus