The study of the decomposition of hair over time

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Re: The study of the decomposition of hair over time

Postby geoffbruton » Wed Feb 20, 2008 6:59 pm

Hi Rosemary,

The possibility of loosened material is a very good idea! Part of the challenge of using this forum to communicate is that I had in my mind's eye a swollen *firm* root, as opposed to something that could include sloughed material. Did it look dry and/or flaky? Did you attempt to remove the root layers to see if they easily came loose? Do you still have any of the pulled hairs? If you do, perhaps this is something that you could check - it would be great to be able to nail this one down! I have not been able to discuss your observations with any of my colleagues yet, but as soon as I get some new information, I'll pass it on to you.

BTW, *major* congratulations on observing the root bands! That is something that is not always seen - so please know that you have done an awesome job!

What were your conclusions from your work? Please let us know!

Thanks.
Geoff.
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Re: The study of the decomposition of hair over time

Postby Rosemary » Wed Jun 04, 2008 7:58 pm

Hi to everyone that helped me or gave me ideas. I want to say thank you for everything. I ended up recieving 3rd place int he science fair and I couldnt have done it without you all. As for my results, I discovered that the time of death could not accurately be determined fromt he size of the hair root alone. Therefore, my next project, which Im going to start in a couple of months, will examine something different. Im not sure what just yet, but im thinking patterns in shape. Ill see. Anyway, I just wanted to say thank you agian. :D
Kelly
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Re: The study of the decomposition of hair over time

Postby Terik Daly » Thu Jun 05, 2008 10:00 am

Rosemary,

Thanks for letting us know how things went. I'm glad that we were able to help!
All the best,
Terik
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Re: The study of the decomposition of hair over time

Postby geoffbruton » Thu Jun 05, 2008 10:49 am

Hi Rosemary,

Thank you so much for letting us know how you got on in your science fair and congratulations on getting third place! :D I hope you're as pleased as we are!

We are looking forward to working with you again.

Best wishes,
Geoff.
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Re: The study of the decomposition of hair over time

Postby Rosemary » Wed Sep 17, 2008 3:56 pm

I am again working on my project for this year. LIke last year, I want to study the hair roots of mice and how they can be related to time of death. Last year I only measured the length and width of the roots I photographed, giving me a rough estimate of the time of death. This year, I want to look at the area and perimeter of the root as well as note unusual characteristics. To do this, I am going to use the ImageJ program. I want to know what you think of this new spin on my old project. I dont think it has been done before, but I want to make sure. Thanks.
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Re: The study of the decomposition of hair over time

Postby MelissaB » Thu Sep 18, 2008 12:11 am

Rosemary,

I think this is a great idea--it flows naturally from your project last year.

Good luck!
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Re: The study of the decomposition of hair over time

Postby geoffbruton » Thu Sep 18, 2008 8:00 am

Good morning, Rosemary!

Great to hear from you. I absolutely agree with Melissa - you correctly identified the limitations of your last project and areas where further research may be beneficial. I will pass on your new project idea to my colleagues in the Trace Evidence Section and will let you know their thoughts or if they have any suggestions.

Welcome back!
Geoff.
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Re: The study of the decomposition of hair over time

Postby heatherL » Thu Sep 18, 2008 10:08 am

Hi Rosemary,

Excellent plan! I have used ImageJ to determine area and perimeter, so let me know if you need any help with the program. You can also use ImageJ to determine the diameter and circularity of the hair. Since the hair shape may change as it decays, these will be good measurements to note. Once you have your photos to analyze, write again and I can explain how to take these measurements using ImageJ.

Good luck!
Heather
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Re: The study of the decomposition of hair over time

Postby Rosemary » Mon Nov 17, 2008 6:27 pm

I have a question that is unrelated to my science project. Right now, since I am a senior, I am taking some time to fill out college applications. I need to indicate a major to enter into. If I want to eventually become a forensic hair and fiber expert, should I major in biology or chemistry? I want to focus on forensics in graduate school and get my bachelor's in a broader topic, like biology or chemistry. I prefer biology but am not sure if that will help me in becoming a hair and fiber expert. If you know a hair and fiber expert, or any forensic scientist, could you ask them what they majored in? Thanks again.
Kelly
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Re: The study of the decomposition of hair over time

Postby geoffbruton » Thu Nov 20, 2008 12:40 pm

Hi Rosemary!

Great to hear from you. I spoke with some of the forensic scientists who work in the Trace Evidence Section (where hair and fiber examinations are performed), and there is actually a split! Some of the scientists are biology graduates, while the other are chemistry graduates. Basically, an undergraduate degree in either subject will be terrific for entry into a crime lab :D

However, I would suggest that you major in a subject that you enjoy - I found university very enjoyable, but very challenging, too. Enjoying what you do (whether at school or at work) certainly makes it a more pleasant experience!

I would also add that an undergraduate degree in biology (over chemistry) would allow you to potentially shift from Trace Evidence to Forensic Biology (where a lot of hair analyses are now being performed); conversely, a chemistry degree would not typically allow this transition, based on the classes you will study at college.

The bottom line is *any* undergraduate degree in a traditional, physical science will be what you need for a career in forensic science - and they have the added bonus of being applicable to other fields, should you ultimately decide that forensic science is not for you.

(For the record, my academic background is in chemistry, though I don't use a great deal of it in my day-to-day work. However, the academic training you will receive will train you how to be a scientist - we are scientists first, forensic scientists second.)

Best of luck to you, and if there is anything more we can do to help, please just let us know.
Geoff.
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Re: The study of the decomposition of hair over time

Postby Rosemary » Sun Jan 25, 2009 1:29 pm

Hello again!
I finished my actual experiment and need to analyze the data I took using the ImageJ software. I am not completely sure how to use it, so I was wondering if I could take Mostman up on the offer to help me use the software.
Kelly
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Re: The study of the decomposition of hair over time

Postby heatherL » Sun Jan 25, 2009 2:03 pm

Hi Rosemary,

The first step is to download the ImageJ software from http://rsbweb.nih.gov/ij/download.html (if you haven't already).

Once you have the program, go to the File menu and choose Open... This will allow you to select the picture from its location on your computer.

When you have the picture open, you can then do a number of things to analyze it. Assuming you have a picture of the hair shaft in cross section (cut through), you can use the elliptical tool to outline the shape of the hair. In my version of ImageJ, this tool is the second button from the left, marked by an oval shape. When you click the button, you can draw an oval that best outlines your hair shaft. Once you have drawn an ellipse that best outlines your hair shaft, go to the Analyze menu and select Measure. A new window will appear, called Results. In this menu, you should see a number of measurements: Area, Mean, Min, Max, Perim., Major, Minor, Angle, and Circ. I will define each of these measurements for you:

Area is the area of the ellipse.

Mean/Min/Max - I believe that these numbers refer to the color values assigned by the program, and would not be relevant for your study.

Perim. is the perimeter of the ellipse.

Major and Minor are the lengths of the major and minor axes of your ellipse. The major axis is the straight line drawn across the widest part of the ellipse, while the minor axis is the straight line drawn across the smallest part of the ellipse, perpendicular to the major axis.

Circ. is a measure of the circularity of the ellipse. This value varies between zero and one. A circularity of 1.0 means that the shape is perfectly circular. The smaller the circularity value, the more elongated your shape.

My advice would be to record the relevant values (Area, Perimeter, and Circularity) in a notebook or spreadsheet as you go.

I hope this helps you get started. If you have other types of measurements you want to take, or other views of the hair, please describe them and I will do my best to help you get the measurements you want. Let me know if you have questions about what I've told you here.

Best wishes,
Heather
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Re: The study of the decomposition of hair over time

Postby Rosemary » Sun Feb 01, 2009 10:30 pm

Thanks for your help on ImageJ. I have another question. I traced the outline of the root and I brought up the Analyze then Measure box. There are values for Area and Perimeter there. Are those values in pixels, or centimeters or what? Do I need to enter any information about the size of the picture I am using so the measurements are accurate? I have been using micrometers to measure the roots from last year, is there any way to get the area and perimeter in microns? Thanks again.
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Re: The study of the decomposition of hair over time

Postby heatherL » Mon Feb 02, 2009 9:21 pm

Hi Rosemary,

I'm glad you're making progress with ImageJ! To be honest, I'm not sure what the exact units are for the values, but I know that they will not be in centimeters or any other standard measurement without calibration. Most likely, the values are in pixels. If you have an ocular micrometer in the photo, or you know the length or some other value in the photo in millimeters (or some other appropriate unit), you can convert the pixellated values into actual units. Could you tell me a little more about the nature of the photos? Did you do your length measurements by including the micrometer in the photo, or did you do the measurements manually through the microscope? Let me know, and I'll do my best to help you. :wink:

Cheers,
Heather
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Re: The study of the decomposition of hair over time

Postby MelissaB » Tue Feb 03, 2009 1:29 am

Heather is right--without calibration, the measurements are in pixels. If you have some scale in your photo, you need to draw a line that corresponds with the length of that scale, then go up to 'Analyze' and 'Set Scale'. You can then fill in the actual length of that line, and change the default centimeters to nanometers.

Hope this helps!
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