Hair analysis can refer to chemical analysis of hair samples, but can also refer to microscopic analysis or comparison. Chemical hair analysis may be considered for retrospective purposes when blood and urine are no longer expected to contain certain contaminants, usually three months or less.
Its most widely used uses are in the field of forensic toxicology and, increasingly, environmental toxicology. Some areas of alternative medicine also use various hair analyzes for environmental toxicology, but these uses are controversial, developing, and not standardized.
Microscopic hair analysis has traditionally been used in forensics as well. The analyst examines a number of different hair characteristics under a microscope, usually comparing the hair taken from a crime scene and hair taken from a suspect. It is still recognized as a useful technique to ensure that hair does not fit. But DNA testing evidence has reversed many beliefs that depend on hair analysis. Since 2012, the Department of Justice has conducted a study of cases in which the test of hair analysis was given by its agents, and found that a high proportion of testimony can not be supported by the state of hair analysis.
Video Hair analysis
In forensic toxicology
Hair analysis is used to detect many therapeutic drugs and drugs, including cocaine, heroin, benzodiazepines, and amphetamines. Hair analysis is less invasive than blood tests, if not quite universally applicable. In this context, it has been reliably used to determine compliance with therapeutic drug regimes or to check the accuracy of witness statements that illicit drugs have not been taken. Hair test is an increasingly common method of assessment in substance abuse, particularly in legal proceedings, or in any situation where the subject may decide not to tell the whole truth about the history of its use. It is also used by private companies that test their employees. Hair analysis has a virtue to show 'history' of drug use due to slow hair growth. Urine analysis may detect drugs taken in the last three days; Hair analysis can sometimes detect use for up to a month, although certain cosmetic treatments (eg hair dyeing) can interfere with this. Hair analysis has the ability to measure a large number of potentially interacting elements, although it is shared with many other drug tests.
The courts allowed from tests in the United States are guided by Daubert standards. The famous court case is United States v. Medina, 749 F.Supp. 59 (E.N.Y.1990) .
Maps Hair analysis
Analysis of microscopic hairs in forensics
Microscopic hair analysis is the science of comparing multiple strands of hair under a microscope and trying to infer if the strands 'fit'. It was accepted as a forensic science in the 1950s. Researchers often monitor more than a dozen attributes, including the distribution of pigments and scale patterns. This technique has been used in criminal investigations to try to tie the hair found at a crime scene, or any other location of the record, and confirm whether the hair matches the suspect. While a simple hair color match may be consistent with a particular suspect already at the scene - black hair at the scene when the suspect has black hair - microscopic hair analysis began to claim a stronger standard in the 1970s. Instead of just "narrowing the field" possibilities, hair analysts claim to be capable of matching certain people, so that hair can be a 'proof' of the presence of a particular suspect. While typed reports often mask the certainty of microscopic hair analysis, witnesses in court will not always be modest. The Montana state crime lab manager testified there was "1 in 10,000 occasions" that the hairs found at the crime scene did not come from the suspect in one case, for example.
Analysis of microscopic hair has a long tradition used in criminal fiction as well; originally popularized in the Sherlock Holmes series before it was used extensively by police. A fictional TV program involving police procedures and detectives has continued to use it since, including Columbo , Quincy, ME , Dexter , and CSI
Skepticism about the powerful claims used by witnesses in the 1970s and 1980s existed at the time. The researchers said in 1974 that the entire process was subjective subjectively, and the FBI wrote in 1984 that hair analysis can not positively match one person. In the 1990s, DNA profiling was introduced as a key new technique in forensic investigation; this introduces a new level of certainty about matching the suspect with the evidence. DNA analysis of old cases from the 1970s and 80s, however, contradicts the conclusions about a number of previous games based on hair analysis.
In 1994, the Department of Justice created a task force that would eventually review 6,000 cases in 2004, focusing on the work of a very passionate inspector, Michael Malone. This review came after reports that careless work by testers at the FBI lab resulted in unreliable forensic evidence in the trial. At first, this investigation was largely silent; The Washington Post reported that "Instead of releasing the findings, they only provide it to the prosecutor in the case of the affected." A case study of hair analysis of FBI Laboratory between 1996 and 2000 was released in 2002 by Max M. Houck and Bruce Budowle. This study shows that 11% of hair analysis "fits" in opposition to DNA analysis. Because the set of cases analyzed is one that is expected to greatly benefit the match - only individual hair is believed to be the police suspect to be sent - this error rate is considered very high.
Kirk L. Odom was convicted of rape in Washington, DC in 1982 by no physical evidence except for microscopic hair analysis performed by the FBI Crime Laboratory. Combined with the identification of witnesses in the line-up (another technique that modern research has proved less reliable than previously thought), Odom was sentenced to twenty years or more in prison. DNA analysis, however, proves that Odom is completely innocent. When Odom was released from prison in 2003, he was officially released in 2012 and paid in a large settlement by the city.
In the same case, Santae Tribble was convicted in 1979 at the age of 17 years in Washington, DC murder because of FBI testimony in a hair hair analysis match found on the scene. But he has three witnesses who gave him an alibi for the moment when the crime was committed. Prosecutors overestimated the reliability of hair analysis in identifying one person, said in a closing statement that "There is one chance, perhaps for all we know, in the 10 million that could be someone else's hair." The DNA test in January 2012, however, shows that the prosecutor's proof, hair, actually does not match the defendant. Tribble was fully released in December 2012, after serving a 28-year prison term that resulted in severe health problems.
The condemnation of defense lawyers about the unreliable hair analysis and over-statements by FBI experts has resulted in the FBI reviewing hair analysis disputes since 2012. Due to what it finds, in July 2013 the Justice Department initiated an "unprecedented" review of cases which involved hair analysis, examined more than 21,000 cases referring to the FBI Lab hair unit from 1982 to 1999.
By 2015, these cases include 32 death penalties, in which FBI experts may have exaggerated the reliability of hair analysis in their testimonies and influenced the verdict. Of these, 14 people have been executed or died in prison. By 2015, DOJ released findings on 268 trials examined so far in which hair analysis is used (ongoing review). The review concludes that in 257 of these 268 trials (95 percent), analysts gave disparate testimony in courts that overestimated the accuracy of the findings that supported prosecution. Approximately 1,200 cases remain checked. The Department emphasized its commitment to follow-up on these cases to correct the mistakes, saying they were "committed to ensuring that affected defendants were informed of past mistakes and that justice was done in every instance.The Department and FBI are also committed to ensuring the accuracy of future hair analysis , as well as the application of all forensic disciplines. "
In 2017, new Attorney General Jeff Sessions, appointed by President Donald Trump, announces that this investigation will be suspended, at the same time he announces the end of a forensic science commission that has worked to set standards on multiple tests and to improve accuracy; it is "a partnership with independent scientists to improve the standards of forensic science". Independent scientists, prosecutors, defense lawyers and judges criticized the termination of the commission, saying that the criminal justice system needs to rely on the best of science.
In environmental toxicology
Analysis of hair samples has many advantages as an initial screening method for the presence of toxic substances that damage health after exposure to air, dust, sediment, soil and water, food and toxins in the environment. The advantages of hair analysis include non-invasive, low cost, and the ability to measure large numbers of potentially interacting, toxic, and biologically important elements. Therefore, head hair analysis is increasingly being used as a preliminary test to see if the individual has absorbed the toxin associated with behavior or health problems.
Detection of long-term element effects
The use of hair analysis appears to be valid for long-term heavy metal load measurements, or lengths, if not a general element analysis measure. Several studies, including hair analysis of Ludwig van Beethoven, have been conducted in conjunction with the National Institutes of Health and the Centers for Disease Control and Prevention.
In a 1999 study of calcium, iron, and zinc concentration of hair in pregnant women and the effects of supplementation, it was concluded that "From the analysis, it is clear that the concentrations of Ca, Fe, and Zn hair can reflect the effects of supplementation... Finally, it can be concluded that deficiency mineral elements may be contaminated by adequate compensation of mineral elemental nutrients. "
Occupational, environmental, and alternative treatments
Source of the article : Wikipedia
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