2011-06-13, 01:17
#289
Tack, Hamilkar. Mycket tacksam. Jag har inte tålamod att kommentera dina svar innan jag ställer nya frågor, vilket jag ber om ursäkt för, men jag har definitivt en del saker jag skulle vilja kommentera, men det får bli i morgon, om du har tid att svara.
Den som följer det här fallet väntar ju nu på rapporten från de oberoende granskarna Stefano Conti och Carla Vecchiotti som skall komma i Juli.
Behåspännet har som bekant numera rostat sönder och kan inte testas och på kniven har man inte hittat några spår av Kerchers DNA, vilket var väntat, eftersom allt testmaterial förbrukades i testet, men inte heller Knox' DNA, vilket däremot var helt oväntat, eftersom det borde funnits där. Istället hittade experterna spår av stärkelse, enligt uppgift. (Någon kommentar om bevishanteringen? Vad kommer stärkelsen från?)
Försvaret (och Waterbury) kan ju ha svårt att skjuta in sig på rätt saker, om de inte får granska alla nödvändiga data. En annan kontrovers angående Stefanonis arbete är alltså försvarets protester mot att de inte fått ut rådatan från DNA-testerna. Hur bedömer man det ur vetenskaplig synpunkt? Finns det verkligen något skäl till varför inte Stefanoni kan lämna ut vad som begärs?
En annan bloggare som engagerat sig i fallet är Chris Halkides, kemist/biokemist från Wilmington ( som förresten egentligen borde vara en svensk stad, eftersom den är byggd på ruinerna av Nya Sverige.)
Här är den senaste kommentaren från honom:
http://viewfromwilmington.blogspot.c...lectronic.html
Expertgranskarna har nu fått tillgång till dessa data, enligt uppgift.

Den som följer det här fallet väntar ju nu på rapporten från de oberoende granskarna Stefano Conti och Carla Vecchiotti som skall komma i Juli.
Behåspännet har som bekant numera rostat sönder och kan inte testas och på kniven har man inte hittat några spår av Kerchers DNA, vilket var väntat, eftersom allt testmaterial förbrukades i testet, men inte heller Knox' DNA, vilket däremot var helt oväntat, eftersom det borde funnits där. Istället hittade experterna spår av stärkelse, enligt uppgift. (Någon kommentar om bevishanteringen? Vad kommer stärkelsen från?)
Citat:
Menar man att profilen har åstadkommits genom cherry-picking, så är det det som man ska skjuta in sig på.
Försvaret (och Waterbury) kan ju ha svårt att skjuta in sig på rätt saker, om de inte får granska alla nödvändiga data. En annan kontrovers angående Stefanonis arbete är alltså försvarets protester mot att de inte fått ut rådatan från DNA-testerna. Hur bedömer man det ur vetenskaplig synpunkt? Finns det verkligen något skäl till varför inte Stefanoni kan lämna ut vad som begärs?
En annan bloggare som engagerat sig i fallet är Chris Halkides, kemist/biokemist från Wilmington ( som förresten egentligen borde vara en svensk stad, eftersom den är byggd på ruinerna av Nya Sverige.)

Här är den senaste kommentaren från honom:
Citat:
(mina fetningar)
Judge Hellmann appointed two independent experts to review the DNA forensic evidence in Amanda Knox’s and Raffaele Sollecito’s appeal. Recently, the experts asked for more time, and reports suggested that they did not yet have access to documents the felt were necessary to carry out this task.
According to Candace Dempsey, forensic scientist under whose supervision the tests were carried out, Dr. Patrizia Stefanoni, turned aside this request. She wrote to Judge Hellman, “In reference to the request of acquisition of CD RAW DATA, one is obligated to explain that the information in the form of this file in the sequencer is never an integral part of the technical report, as far as the object being tested by the forensic geneticist, namely the DNA profile, and that it is already reported in the electropherogram printout, connected to the technical report on which all of the useful date and an evaluation of the genetic profile are reported… Finally, the request asked for by the expert consultants relative to the acquisition of the CD RAW DATA appears incomplete in so much as the name of the ‘sample file’ requested was not specified…”
To help me consider Dr. Stefanoni's refusal refusal, I have consulted with DNA forensics professionals Dan Krane and Jason Gilder of Forensic Bioinformatics, and I gratefully acknowledge their help. The continued lack of file release with respect to the DNA profiling of this case has been a recurring theme of this blog.
Her arguments against releasing further information are essentially:
(1) All of the necessary data are already in the paper printouts of the electropherograms.
(2) The request for data files is insufficiently specific.
Let us examine point (1) first. Dr. Stefanoni’s position appears to be the same as it was when Dr. Pascali was refused data, as noted in Raffaele’s appeal. Yet some of the electropherograms only provide the number of repeats, not the peak height for each peak. Peak heights are essential to evaluate peak height imbalance within a locus, which bears on the question of whether or not a sample is in the low-template range, and whether two peaks within a locus belong to the same or to two different individuals. Peak heights can also be used to quantify the severity of degradation when one compares DNA fragments of different lengths. Peak height ratios also help one to decide whether or not a small peak is a type of artifact known as a stutter. A careful examination of these small peaks is especially important in helping to judge what other DNA is present on the bra clasp besides Meredith’s and presumably Raffaele’s.
In addition, having the electronic data files allows one to calculate a run-specific limit of detection (Gilder et al., J. Forensic Science, January 2007, 52 (1), 97). This process sets a lower limit on the size of which peaks to accept, based on the amount of noise. It can also be helpful in detecting a type of artifact known as a pull-up. There are four types of dyes used in DNA profiling, each with a different wavelength (color) of detection. Each dye is ordinarily detected in its own channel. Sometimes a large peak gives a small spurious signal because of bleeding from one channel into another (Butler, Forensic DNA Typing (2005), pp. 336-337; 384). According to Christine Funk and Dr. Simon Ford, “Pull-up can usually be identified through careful analysis of the position of peaks across the color spectrum, but there is a danger that pull-up will go unrecognized, particularly when the result it produces is consistent with what the analyst expected or wanted to find.”
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According to Candace Dempsey, forensic scientist under whose supervision the tests were carried out, Dr. Patrizia Stefanoni, turned aside this request. She wrote to Judge Hellman, “In reference to the request of acquisition of CD RAW DATA, one is obligated to explain that the information in the form of this file in the sequencer is never an integral part of the technical report, as far as the object being tested by the forensic geneticist, namely the DNA profile, and that it is already reported in the electropherogram printout, connected to the technical report on which all of the useful date and an evaluation of the genetic profile are reported… Finally, the request asked for by the expert consultants relative to the acquisition of the CD RAW DATA appears incomplete in so much as the name of the ‘sample file’ requested was not specified…”
To help me consider Dr. Stefanoni's refusal refusal, I have consulted with DNA forensics professionals Dan Krane and Jason Gilder of Forensic Bioinformatics, and I gratefully acknowledge their help. The continued lack of file release with respect to the DNA profiling of this case has been a recurring theme of this blog.
Her arguments against releasing further information are essentially:
(1) All of the necessary data are already in the paper printouts of the electropherograms.
(2) The request for data files is insufficiently specific.
Let us examine point (1) first. Dr. Stefanoni’s position appears to be the same as it was when Dr. Pascali was refused data, as noted in Raffaele’s appeal. Yet some of the electropherograms only provide the number of repeats, not the peak height for each peak. Peak heights are essential to evaluate peak height imbalance within a locus, which bears on the question of whether or not a sample is in the low-template range, and whether two peaks within a locus belong to the same or to two different individuals. Peak heights can also be used to quantify the severity of degradation when one compares DNA fragments of different lengths. Peak height ratios also help one to decide whether or not a small peak is a type of artifact known as a stutter. A careful examination of these small peaks is especially important in helping to judge what other DNA is present on the bra clasp besides Meredith’s and presumably Raffaele’s.
In addition, having the electronic data files allows one to calculate a run-specific limit of detection (Gilder et al., J. Forensic Science, January 2007, 52 (1), 97). This process sets a lower limit on the size of which peaks to accept, based on the amount of noise. It can also be helpful in detecting a type of artifact known as a pull-up. There are four types of dyes used in DNA profiling, each with a different wavelength (color) of detection. Each dye is ordinarily detected in its own channel. Sometimes a large peak gives a small spurious signal because of bleeding from one channel into another (Butler, Forensic DNA Typing (2005), pp. 336-337; 384). According to Christine Funk and Dr. Simon Ford, “Pull-up can usually be identified through careful analysis of the position of peaks across the color spectrum, but there is a danger that pull-up will go unrecognized, particularly when the result it produces is consistent with what the analyst expected or wanted to find.”
-----------------
http://viewfromwilmington.blogspot.c...lectronic.html
Expertgranskarna har nu fått tillgång till dessa data, enligt uppgift.
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Senast redigerad av HusvagnSvensson 2011-06-13 kl. 01:21.
Senast redigerad av HusvagnSvensson 2011-06-13 kl. 01:21.