Bequests, sibling rivalry, and rent seeking

We examine bequest-sharing rules where sibling rivalry creates wasteful competition for intergenerational transfers. We show that equal division of bequests minimizes rent-seeking expenditures by siblings while primogeniture maximizes rent-seeking costs. Our results lend theoretical support to the empirical findings of equal bequests without appeal to complex models of the parent-child relationship.     

Mitochondrial DNA sequencing of beetle larvae (Nitidulidae: Omosita) recovered from human bone

The isolation, amplification, and characterization of human DNA from hematophagous (blood feeding) and necrophagous (carrion feeding) arthropods have been advanced significantly by the development of polymerase chain reaction (PCR) DNA sequencing methodologies. Historically, DNA technology has been successfully utilized to identify individual hosts upon which species of hematophagous arthropods have fed. The analysis of hematophagous insects' gut content blood meals has led to major advances in medical entomology and vector-borne disease epidemiology. In the forensic arena, the ability to apply similar techniques to insects recovered from badly decomposed remains has been greatly enhanced through the advent of mitochondrial DNA (mtDNA) techniques. Mitochondrial DNA analyses have been utilized to identify both the human remains upon which fly larvae (maggots) have fed and the species of the larvae themselves. The preliminary work detailed here demonstrates, for the first time, the successful application of mtDNA sequencing techniques to the analysis of necrophagous beetle larvae. A small sample of sap beetle larvae, Omosita spp. (Coleoptera: Nitidulidae), was collected from human skeletal remains during anthropological examination and analyzed for human DNA using mtDNA sequencing. The beetle larvae yielded mtDNA matching that of the host human bone. The results detailed here further demonstrate the robust nature of human mtDNA and the ability to recover valuable mtDNA evidence from forensically important, late decompositional stage insect species.     

Allele frequencies and haplotypes of eight Y-short tandem repeats in Bantu population living in Central Africa

Eight Y chromosome short tandem repeats (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385I/II) were used to assess haplotype distribution in non-selected, unrelated Bantu males living in Central Africa [N. Mathias, M. Bayes, C. Tyler-Smith, Highly informative compound haplotypes for the human Y chromosome, Hum. Mol. Genet. 3 (1994) 115-123; L. Roewer, J. Arnemann, N.K. Spurr, K.H. Grzeschik, J.T. Epplen, Simple repeat sequences on the human Y chromosome are equally polymorphic as their autosomal counterparts, Hum. Genet. 89 (1992) 389-394; P. De Knijff, M. Kayser, A. Caglia, D. Corach, N. Fretwel, C. Gehrig, G. Graziosi, F. Heidorn, S. Herrmann, B. Herzog, M. Hidding, K. Honda, M. Jobling, M. Krawczak, K. Leim, S. Meuser, E. Meyer, W. Oesterreich, A. Pandya, W. Parson, G. Penacino, A. Perez-Lezaun, A. Piccini, M. Prinz, C. Schmitt, P. M. Schneider, R. Szibor, J. Teifel-Greding, G. Weishold, L. Rower, Chromosome Y microsatellites: population genetic and evolutionary aspects, Int. J. Legal Med. 110 (1997) 134-149; M. Kayser, A. Caglia, D. Corach, N. Fretwel, C. Gehrig, G. Graziosi, F. Heidorn, S. Herrmann, B. Herzog, M. Hidding, K. Honda, M. Jobling, M. Krawczak, K. Leim, S. Meuser, E. Meyer, W. Oesterreich, A. Pandya, W. Parson, G. Penacino, A. Perez-Lezaun, A. Piccini, M. Prinz, C. Schmitt, P. M. Schneider, R. Szibor, J. Teifel-Greding, G. Weishold, P. de Knijff, L. Rower, Evaluation of Y chromosome STRs: a multicenter study, Int. J. Legal Med. 110 (1997) 125-133, 141-149]. One hundred and sixty-five full haplotypes were obtained from Bantu males. The most common haplotype (DYS19-15, DYS389I-13, DYS389II-30, DYS390-21, DYS391-10, DYS392-11, DYS393-13, DYS385I/II-15,17) was shared by 5.5% of individuals. In the Bantu population in Central Africa, the haplotype diversity and the discrimination capacity of Y-STR may be estimated at 99.14% and 0.5333, respectively.     

Proactive Policing: a Summary of the Report of the National Academies of Sciences,Engineering, and Medicine

This paper provides a summary of our report for the National Academy of Sciences, Engineering, and Medicine on proactive policing. We find that there is sufficient scientific evidence to support the adoption of many proactive policing practices if the primary goal is to reduce crime, though the evidence base generally does not provide long-term or jurisdictional estimates. In turn, we conclude that crime prevention outcomes can often be obtained without producing negative community reactions. However, the most effective proactive policing strategies do not appear to have strong positive impacts on citizen perceptions of the police. At the same time, some community-based strategies have begun to show evidence of improving the relations between the police and public. We conclude that there are likely to be large racial disparities in the volume and nature of police–citizen encounters when police target high-risk people or high-risk places, as is common in many proactive policing programs. We could not conclude whether such disparities are due to statistical prediction, racial animus, implicit bias, or other causes.

     

Variation of δ2H, δ18O & δ13C in crude palm oil from different regions in Malaysia: Potential of stable isotope signatures as a key traceability parameter

A total of 33 crude palm oil samples were randomly collected from different regions in Malaysia. Stable carbon isotopic composition (δ¹³C) was determined using Flash 2000 elemental analyzer while hydrogen and oxygen isotopic compositions (δ²H and δ¹⁸O) were analyzed by Thermo Finnigan TC/EA, wherein both instruments were coupled to an isotope ratio mass spectrometer. The bulk δ²H, δ¹⁸O and δ¹³C of the samples were analyzed by Hierarchical Cluster Analysis (HCA), Principal Component Analysis (PCA) and Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA). Unsupervised HCA and PCA methods have demonstrated that crude palm oil samples were grouped into clusters according to respective state. A predictive model was constructed by supervised OPLS-DA with good predictive power of 52.60%. Robustness of the predictive model was validated with overall accuracy of 71.43%. Blind test samples were correctly assigned to their respective cluster except for samples from southern region. δ¹⁸O was proposed as the promising discriminatory marker for discerning crude palm oil samples obtained from different regions. Stable isotopes profile was proven to be useful for origin traceability of crude palm oil samples at a narrower geographical area, i.e. based on regions in Malaysia. Predictive power and accuracy of the predictive model was expected to improve with the increase in sample size. Conclusively, the results in this study has fulfilled the main objective of this work where the simple approach of combining stable isotope analysis with chemometrics can be used to discriminate crude palm oil samples obtained from different regions in Malaysia. Overall, this study shows the feasibility of this approach to be used as a traceability assessment of crude palm oils.     

Forensic entomology in the Hawaiian Islands. Three case studies

Three instances of the use of entomological techniques for the estimation of postmortem interval in homicide cases on the island of Oahu, Hawaiian Islands, are presented. These cases represent differing stages of decomposition and range from 8 to 53 days postmortem.     

A BASIC algorithm for calculating the postmortem interval from arthropod successional data.

A computer algorithm, implemented in the BASIC language, is presented for calculating the postmortem interval (PMI) from arthropod successional data. Entomology-assisted determination of the PMI promises to be a reliable technique in cases of homicide, suicide, accidental death, and unattended death due to natural causes. The program requires, as input, the identity of arthropod taxa recovered from human remains in a death scene investigation and machine-readable data on carrion-associated arthropod taxa and their known successional patterns of activity for the same geographical area. The program performs rapid comparisons of these lists and, on output, calculates an upper and lower estimate of the PMI, identifies the definitive taxa for these limits, and determines if the remaining corpse taxa have known successional patterns that are consistent for this estimate. An alternate output is provided if one or more corpse taxa do not overlap all the others at any single time in the succession. In that event, the user is prompted to recheck the identity of the non-overlapping taxon or taxa or reevaluate the environmental circumstances surrounding the case in question. Results of the analysis are saved to an ASCII file for output to a printer for making paper copies useful for the entomologist's Case Study Final Report. This program may make possible wider use of this technique in law enforcement and medical investigator offices that utilize both forensic entomologist expertise and IBM PCs (or compatible computers).     

Preliminary Observations of Arthropods Associated with Buried Carrion on Oahu

Several studies in Hawaii have focused on arthropod succession and decomposition patterns of surface remains, but the current research presents the first study to focus on shallow burials in this context. Three domestic pig carcasses (Sus scrofa L.) were buried at the depths of 20–40 cm in silty clay loam soil on an exposed ridge on the leeward side of the volcanically formed Koolau Mountain Range. One carcass was exhumed after 3 weeks, another after 6 weeks, and the last carcass was exhumed after 9 weeks. An inventory of arthropod taxa present on the carrion and in the surrounding soil and observations pertaining to decomposition were recorded at each exhumation. The longer the carrion was buried, the greater the diversity of arthropod species that were recovered from the remains. Biomass loss was calculated to be 49% at the 3‐week interval, 56% at the 6‐week interval, and 59% at the 9‐week interval.