WWW.DISSERTATION.XLIBX.INFO
FREE ELECTRONIC LIBRARY - Dissertations, online materials
 
<< HOME
CONTACTS



Pages:   || 2 | 3 | 4 | 5 |

«Document Title: Assessing Error in PMI Prediction Using a Forensic Entomological Computer Model Author(s): Daniel Slone, Susan Gruner, Jon Allen ...»

-- [ Page 1 ] --

The author(s) shown below used Federal funds provided by the U.S.

Department of Justice and prepared the following final report:

Document Title: Assessing Error in PMI Prediction Using a

Forensic Entomological Computer Model

Author(s): Daniel Slone, Susan Gruner, Jon Allen

Document No.: 211760

Date Received: October 2005

Award Number: 2000-RB-CX-0002

This report has not been published by the U.S. Department of Justice.

To provide better customer service, NCJRS has made this Federally- funded grant final report available electronically in addition to traditional paper copies.

Opinions or points of view expressed are those of the author(s) and do not necessarily reflect the official position or policies of the U.S.

Department of Justice.

ASSESSING ERROR IN PMI PREDICTION USING A FORENSIC

ENTOMOLOGICAL COMPUTER MODEL

NIJ #2000RBCX0002 FINAL REPORT, REVISED OCTOBER 2004 Daniel H. Slone (USGS Florida Integrated Science Center) Susan V. Gruner (University of Florida, Entomology and Nematology) Jon C. Allen (University of California, Santa Barbara, Ecology and Evolution) Summary The study described herein details investigations into the thermal behavior of forensically important maggots, the effect of internal maggot mass heat generation on maggot development time, and the sources and magnitudes of error affecting a phenological computer model that predicts the likely post-mortem interval (PMI) of human remains found long after the person’s demise. Field studies were performed in north Florida and northwest Indiana with 88 domestic pigs (Sus scrofa) allowed to become colonized naturally in a wooded setting by blowflies (Insecta, Diptera: Calliphoridae) other carrion-feeding flies, and other insects, while being protected from larger scavengers. Adult flies found around the corpses were captured and identified, and samples from maggot masses were characterized by species and life stage. Each maggot mass was also measured for dimensions and temperature. Some pigs were further monitored with a linear probe that continuously measured the internal temperature of the pig and masses in 12 locations along the probe The computer model was revised to accept parameters for 3 species of fly: Chrysomya rufifaces, Cochliomyia macellaria, and Phormia regina using data from the Ph.D. thesis of J.H.

Byrd. It was also enhanced with a maggot mass temperature submodel using data gathered from the linear probe, and individual temperatures of maggot masses. Using this expanded model, we ran simulations using weather data from the Florida test plots, and compared those PMI predictions to actual results found in the field trials.

With the few useable field trials, the time of death estimates have been found to be quite accurate in our limited testing, with preliminary error rates in the 1-2% range. The majority of the field trials were not useable at this time because we have no phenology data for the most common fly found, Phaenicia coeruleiviridis. When phenology is obtained for that species, we can run those trials and obtain a more robust set of error measurements. We also will perform validaiton using cold-case criminal data.

Sensitivity analysis showed that the most sensitive parameter in the model is the growth rate of the maggots. This is followed closely by air temperature, which becomes less important as the mass grows larger and has better internal temperature regulation. Other parameters were less sensitive, such as the rate at which heat contained in the air, soil, or body transfers to other locations. We also analyzed error rates brought about by sampling imprecision and found, unsurprisingly, that larger sample sizes lead to greater precision in the model.

–  –  –

Forensic entomology is the broad field where arthropod science and the judicial system

interact (Hall 2001). The field of forensic entomology has been divided into three areas:

medicocriminal entomology (also referred to as medicolegal entomology), urban entomology and stored product entomology. Information gained from forensic entomology typically is used to determine time of death, place of death and other issues of medical or legal importance (Gordh and Headrick 2001). Urban entomology concentrates mainly on controversies involving termites, cockroaches, and other insect problems accruing to the human environment, whereas stored product entomology involves disputes over arthropods and arthropod parts in food and other products (Hall 2001).

When human remains are found, the most important questions are usually how, when, where and why the person died. Historically, determination of the postmortem interval has been estimated through observation and measurement of body conditions such as core body temperature (Nelson 1999), muscular flaccidity, rigor mortis, lividity, pallor of the skin and others (Smith 1986; Bass 2001; Byrd and Castner 2001). Entomological specimens in medicolegal death investigations can be reliable indicators for estimating the postmortem interval (PMI) in both early and advanced stages of cadaver decomposition (Nuorteva 1977;

Smith 1986; Goff et al. 1988; Kashyap and Pillay 1989; Greenberg 1991; Byrd 1998).

Insects and other invertebrates feeding on carrion form a distinct faunal succession associated with the various stages of decay (Smith 1986). Recognition of the different immature stages of each species involved, together with the knowledge of their rates of development, can give an indication of the PMI (Smith 1986). A forensic entomologist can also determine the age of immature insects, based upon knowledge of the variables regarding insect invasion of human remains. Evaluation and interpretation of entomological evidence at a crime scene can address other complicated issues in addition to time of death, including: season of death, geographic location of death, movement or storage of the remains following death, location of specific sites of trauma on the body, sexual molestation and use of drugs (Haskell et al. 1997).





In case studies conducted in varying temperate and tropical climates, where human remains were exposed to the environment for 2.5 months or less, entomology-based PMI estimates differed by ± 48 hours when compared with the intervals determined by independent corroboration such as confessions and eyewitness testimony (Greenberg 1985; Goff, Omori et al.

1988; Lord 1990; Byrd 1998). Clearly, entomological evidence is the most reliable scientific means of estimating a PMI of 72 hours or more (Kashyap and Pillay 1989; Catts and Haskell 1990; Anderson 2001).

The study of insects important to forensic entomology has been conducted mainly through the use of non-human animal models. Decomposition studies worldwide have used a variety of different carcass types and sizes including: dogs (Reed 1958; Jiron and Cartin 1981;

Early and Goff 1986), cats (Early and Goff 1986), voles (Lane 1975), rats (Greenberg 1990;

Tomberlin and Adler 1998; Faucherre et al. 1999; Kocarek 2001), squirrels (Johnson 1975), foxes (Easton and Smith 1970; Smith 1975), pigs (Payne 1965; Tullis and Goff 1987; Haskell 1989; Anderson and VanLaerhoven 1996; Tessmer and Meek 1996; Richards and Goff 1997;

deCarvalho et al. 1999; Shahid et al. 1999; Davis and Goff 2000; deCarvalho and Linhares 2001;

Wolff et al. 2001; Tenorio et al. 2003), seals (Lord and Burger 1984), guinea pigs (Bornemissza 1956), mice (Putnam 1978; Blackith and Blackith 1989), lizards and toads (Cornaby 1974), raccoons (Joy et al. 2002), turtles (Abell et al. 1982), poultry (Hall and Doisy 1993; Tessmer, This document is a research report submitted to the U.S. Department of Justice. This report has not been published by the Department. Opinions or points of view expressed are those of the author(s) and do not necessarily reflect the official position or policies of the U.S. Department of Justice.

Meek et al. 1995), sheep (Deonier 1940), rabbits (Denno and Cothran 1975; Tantawi et al. 1996;

Bourel et al. 1999), elephants (Coe 1978), opossums (Goddard and Lago 1985), black bears (Anderson 1998), and impala (Braack 1981). The only faunal succession research on human remains was conducted in Tennessee (Rodriguez and Bass 1983; Catts and Haskell 1990).

Human cadavers are not easily obtainable for detailed decomposition studies. Pigs, Sus scrofa, are omnivorous, have similar gut fauna, are relatively hairless and have skin that is very similar to that of humans (Anderson and VanLaerhoven 1996). The putrefaction of pigs proceeds approximately at the same rate as for human bodies that are of the same torso weight (Campobasso et al. 2001). Haskell’s 1989 study in Tennessee (unpublished) compared the insect community structure and decomposition rates between adult and infant human remains and that of pigs and found no significant difference in the composition of the insect communities in human and pig carcasses (Campobasso et al. 2001). Therefore, twenty-two kg pigs have been recommended as suitable human models for adult decomposition (Catts and Goff 1992).

Biology of Calliphorid Flies Two major groups of insects are predictably attracted to cadavers and provide the majority of information in forensic investigation; the flies and the beetles (Castner 2001). This study focuses on the Family Calliphoridae, commonly called the blow flies, which are the first to find and colonize human corpses. Experimental studies indicate that these flies arrive at carcasses within minutes of their exposure ( Shean et al. 1993; Byrd and Castner 2001).

There are more than 1000 species of blow flies throughout the world. This family includes the green bottle flies (genus Phaenicia), blue bottle flies (genus Calliphora), the screwworm flies (genus Cochliomyia) and the black blow flies (tribe Phormiini). The common name is derived from the manner in which these flies deposit their eggs (Hall 1948). The family name means ‘beauty bearer’ in Greek (Greenberg and Kunich 2002).

Calliphorid flies have highly specialized sense organs on their antennae that are stimulated by putrefaction odors and gases that are released during post-mortem decomposition of organic matter. Studies indicate that some species of Phaenicia are attracted to various organic sulphur compounds, either alone or in combination with hydrogen sulphide, and also by ammonia (Cragg 1956; Cragg and Cole 1956; Ashworth and Wall 1994; Wall and Warnes 1994).

Nilssen used insect flight traps baited with dimethyl trisulphide and found that the chemical was a strong attractant for some calliphorids (Nilssen et al. 1996). Odors from Proteus mirabilis, a bacterial infection that occurs in the fleece in sheep, are attractants to some calliphorid flies (Morris et al. 1998).

Landing behavior of calliphorids is also dependent on visual cues such as color (Wall et al. 1992, Hall et al.1995). Oviposition is elicited primarily by the presence of ammonia-rich compounds, moisture, pheromones, and tactile stimuli (Ashworth and Wall 1994) yet was rarely stimulated by chemicals used alone (Cragg 1956). Unfortunately, the complex interaction of semiochemical and visual cues used for resource location remains little studied in calliphorids (Wall and Fisher 2001).

Blow flies are heliotropic and usually rest at night. Eggs are not usually laid at night although clearly there are exceptions. Green (1951) observed that Calliphora deposited eggs at night under artificial light in slaughter houses. He wrote that “under laboratory conditions it has been found that Calliphora erythrocephala (now called C. vicina), Lucilia sericata and Phormia terrae-novae will all oviposit in total darkness, although Wardle (1930) asserts that blowflies do not oviposit in the complete absence of light”. Greenberg (1990) observed Phaenicia sericata, This document is a research report submitted to the U.S. Department of Justice. This report has not been published by the Department. Opinions or points of view expressed are those of the author(s) and do not necessarily reflect the official position or policies of the U.S. Department of Justice.

Phormia regina (Meigen) and Calliphora vicina (Robineau-Desvoidy) ovipositing a very small number of eggs on rat carrion. Singh (2001) pointed out that the flies in Greenberg’s experiment probably were resting on a nearby bush and literally crawled over to oviposit on the rat carrion, thus indicating that blow flies were not actively searching for an oviposition site. Nocturnal oviposition has not been observed in large-scale studies in other areas (Greenberg 1990; Byrd 1997; Haskell et al.1997.

Other factors that affect blow fly activity are temperature, size of the carcass, geographical location, humidity, light and shade, seasonal and daily periodicity, availability of food and competition, maggot mass temperature and manner of death.

Description of original “maggot model” Our model of forensic fly phenology was developed using the Matlab/Simulink software simulation package (Figure 1). Mathematically speaking, we use distributed delays (Manetch 1976, van Sickle 1977) to model the developmental delay process. MacDonald (1978) has called this method the ‘linear chain trick’. For each biological stage (egg, larva1, larva2,…) a chain of differential equations is written as,

–  –  –

This document is a research report submitted to the U.S. Department of Justice. This report has not been published by the Department. Opinions or points of view expressed are those of the author(s) and do not necessarily reflect the official position or policies of the U.S. Department of Justice.

MATERIALS AND METHODS

The use of human corpses for field studies in maggot development is generally not legal or practical, so a substitute decomposition subject was needed. As determined in other decomposition studies (Haskell 1989, Anderson and VanLaerhoven 1996, Campobasso et al.

2001) the rate decomposition and fly colonization in pigs is very similar to that of humans:

therefore, dead pigs, Sus scrofa L, were used as animal models for this study.



Pages:   || 2 | 3 | 4 | 5 |


Similar works:

«Version: Jan 7, 2005 Rx Only ABRAXANETM for Injectable Suspension (paclitaxel protein-bound particles for injectable suspension) (albumin-bound) (Patient Information Enclosed) WARNING ABRAXANE for Injectable Suspension (paclitaxel protein-bound particles for injectable suspension) should be administered under the supervision of a physician experienced in the use of cancer chemotherapeutic agents. Appropriate management of complications is possible only when adequate diagnostic and treatment...»

«33 La CONEAU, organismo descenEntre 1998 y 2004 la CONEAU publicó tralizado que funciona en jurisdicveintiun informes en su serie de Evaluación del Ministerio de Educación ciones Externas. Al retomar esa tarea en La Universidad Nacional de General de la Nación, es la encargada de Universidad Nacional de General Sarmiento el año del Bicentenario, se editan Sarmiento fue creada en 1993, durante evaluar las instituciones y acredisimultáneamente seis nuevos títulos, tar las carreras...»

«Common Triage Calls Newborn My newborn has a fever-do we need to be seen? A baby who is less than 2 months old with a fever over 100.5 needs to call the office 24 hours a day. My newborn’s umbilical cord site is oozing-what should we do? Clean the umbilical cord twice a day with hydrogen peroxide or alcohol. Be sure and get all the way down to where the skin and cord connect. If the oozing continues then make an appointment to be seen during office hours. You need to call the office if the...»

«Provided by the author(s) and NUI Galway in accordance with publisher policies. Please cite the published version when available. Reinvented, Re-imagined and Somehow Dislocated: The Title Evolution of Two John McGahern Short Stories Author(s) Fahey, Fergus Publication 2008-09-03T16:03:03Z Date Publication Fahey, F., Reinvented, Re-imagined and Somehow Dislocated: Information The Evolution of Two John McGahern Short Stories (2008) Item record http://hdl.handle.net/10379/16 Downloaded...»

«Chia-Huei Wu and Sharon K. Parker The role of leader support in facilitating proactive work behaviour: a perspective from attachment theory Article (Accepted version) (Refereed) Original citation: Wu, Chia-Huei and Parker, Sharon K. (2014) The role of leader support in facilitating proactive work behaviour: a perspective from attachment theory. Journal of Management, online. ISSN 1557-1211 (In Press) DOI: 10.1177/0149206314544745 © 2014 Southern Management Association This version available...»

«Laser Locking with Doppler-free Saturated Absorption Spectroscopy Paul L. Stubbs, Advisor: Irina Novikova W&M Quantum Optics Group May 12, 2010 Abstract The goal of this project was to lock the frequency of a 795 nm diode laser using a saturated absorption spectroscopy method. Laser locking in AMO physics is done to stabilize the frequency of lasers used in the laboratory in order to make results more reliable and reproducible. Locking the laser frequency to a particular absorption resonance...»

«Snow ballsPretty Faced Wallaby raised 1990 Introduction to the Care and Handraising of Macropods Written and complied by Enid Latham Ph/Fax: Enid (02) 6887-2102 Email: mummaroo@bigpond.com.au 1 Table of Contents RESCUE OF A JOEY4 ASSESSMENT OF A JOEY _4 Immediate Care 4 Heating _ 4 Dehydration _ 5 COMMITMENT 5 EQUIPMENT 6 Pouches 7 Hygiene 7 FEEDING YOUR JOEY8 Formulas 9 Quantity Feeding Guide _ 10 Guide to feeding Wallabies 10 Other Foods 10 TOILETING 11 PERSONAL RECORDS _11 FENCING11...»

«Improving Term Extraction with Terminological Resources Sophie Aubin, Thierry Hamon To cite this version: Sophie Aubin, Thierry Hamon. Improving Term Extraction with Terminological Resources. Tapio Salakoski, Filip Ginter, Sampo Pyysalo, Tapio Pahikkala. 2006, Springer, pp.380, 2006, LNAI 4139. hal-00091444 HAL Id: hal-00091444 https://hal.archives-ouvertes.fr/hal-00091444 Submitted on 6 Sep 2006 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for...»

«http://assembly.coe.int Doc. 13993 02 March 2016 Application of the European Charter for Regional or Minority Languages Biennial Report by the Secretary General of the Council of Europe to the Parliamentary Assembly Communication Secretary General F 67075 Strasbourg Cedex | assembly@coe.int | Tel: +33 3 88 41 2000 | Fax: +33 3 88 41 2733 Doc. 13993 Communication Contents Page 1. Introduction 2. Monitoring the Application of the Charter in States Parties 3. Assistance to States preparing...»

«Insted Consultancy (www.insted.co.uk) Bullying in Schools around Racism, Culture and Religion – How to prevent it and what to do when it happens A set of workshop papers, 2007 LIST OF PAPERS 1. A JIGSAW ACTIVITY 2. RACIST BULLYING AND OTHER FORMS OF BULLYING 3. CRITICAL INCIDENTS 4. NOTES ON THE INCIDENTS 5. STARTING POINTS FOR SCHOOL SELF-EVALUATION 6. CLARIFYING TERMS AND CONCEPTS 7. ASPECTS OF LANGUAGE 8. FIVE KEY PRINCIPLES 9. TEACHING ABOUT THE ABOLITION OF SLAVERY 10. SOME CURRENT...»

«Medications List ANTIARRHYTHMICS Amiodarone: Amiodarone is used for treatment of atrial fibrillation, Ventricular tachycardia and other arrhythmias. It is mainly used as Rhythm control therapy and tries to change abnormal heart rhythm to normal sinus rhythm and maintains it. This medication must be taken with meals as it is better absorbed with food. It is important to have regular checkups, blood tests including thyroid function tests and liver function tests, chest X-Rays and eye exams before...»

«Windsor, North Carolina May 23, 2016 Regular Meeting The Bertie County Board of Commissioners convened for its regular meeting at 7:00PM inside the Blue Jay Fire Department located at 1653 Indian Woods Road. The following members were present or absent: Ronald “Ron” Wesson, District I Present: Stewart White, District II Tammy A. Lee, District III John Trent, District IV Ernestine (Byrd) Bazemore, District V Absent: None Staff Present: County Manager Scott Sauer Clerk to the Board Sarah S....»





 
<<  HOME   |    CONTACTS
2016 www.dissertation.xlibx.info - Dissertations, online materials

Materials of this site are available for review, all rights belong to their respective owners.
If you do not agree with the fact that your material is placed on this site, please, email us, we will within 1-2 business days delete him.