Multivariate Analysis in Management, Engineering and the Sciences

Recently statistical knowledge has become an important requirement and occupies a prominent position in the exercise of various professions. In the real world, the processes have a large volume of data and are naturally multivariate and as such, require a proper treatment. For these conditions it is difficult or practically impossible to use methods of univariate statistics. The wide application of multivariate techniques and the need to spread them more fully in the academic and the business justify the creation of this book. The objective is to demonstrate interdisciplinary applications to identify patterns, trends, association sand dependencies, in the areas of Management, Engineering and Sciences. The book is addressed to both practicing professionals and researchers in the field

Applications of chemometrics to the analysis and interpretation of forensic physical evidence

Forensic investigations often rely upon items of physical evidence. However, current interpretation protocols for such evidence are subjective, leading to potential bias in forensic examinations. Chemometric techniques may be used to develop more objective methods for assessing evidential significance, as well as establishing statistically validated evidential procedures. This dissertation describes the application of chemometrics to various aspects of physical evidence examination, with a specific focus on textile fibres, pen inks and explosive residues

Estimativa temporal de impressões digitais latentes : desenvolvimento de métodos espectroscópicos com aplicação quimiométrica e de imageamento químico por espectrometria de massas para a rotina forense

A Papiloscopia é uma área de Ciências Forenses que é responsável pela identificação humana, sendo as impressões digitais o elementos-chave, que são uma das principais e mais frequentes evidências físicas em investigações criminais. Um desafio para a análise das impressões digitais é o estabelecimento de sua datação (envelhecimento), ou seja, o período decorrido entre sua afixação na cena do crime e a análise do laboratório. O envelhecimento da impressão digital presente em uma cena de crime pode ser útil para discernir um evento ou situá-lo na linha temporal investigativa. No entanto, as impressões digitais são uma matriz biológica complexa com fatores de variabilidade intrínseca e extrínseca ao doador, sendo um desafio não apenas para identificar os componentes bioquímicos, mas também para entender seus padrões de envelhecimento. Para isso, os métodos analíticos guiaram esta tese em duas revisões: a primeira, foram selecionadas as classes de métodos mais utilizadas para análise de impressão digital e a segunda, quais componentes bioquímicos presentes nas amostras fornecem informações sobre a estimativa temporal das amostras. Em relação às classes de métodos, a espectrometria de massa provou ser a técnica promissora para análise de impressão digital, destacando a fonte de ionização/dessorção assistida por matriz (MALDI MS) como a mais usada. Com isso, um método MALDI MS foi desenvolvido com a aplicação de imagens químicas (IMS) que, a partir da seleção de íons dos componentes de maior intensidade nas amostras, permitiram a visualização de impressões digitais cinquenta dias após seu depoimento. A segunda classe de métodos mais utilizada foi a espectroscopia, na qual um método de Microespectroscopia de Infravermelho com Transformada de Fourier (μ-FTIR) foi desenvolvido para a análise de impressões digitais sebáceas monitoradas por uma semana, seguidas pelo uso do método não- supervisionado de análise linear discriminante (LDA). Observou -se que, apesar dos perfis do doador serem semelhantes, o método permitiu a elaboração de uma tendência de separação entre as amostras com base no tempo de deposição. E, além disso, foi possível separar as amostras por doador. Assim, este trabalho compõe um passo em direção à aplicação da ciência analítica à Papiloscopia como um recurso fundamental da justiça na geração de evidências robustas para a busca da verdade.Fingerprint Analysis is the area of Forensic Sciences that deals with human identification, having fingerprints as key elements, which are one of the main and most frequent physical evidences in criminal investigations. A challenge for the fingerprint analysis is the establishment of their aging, that is, the period elapsed between their affixation at the crime scene and the forensic analysis. The fingerprint aging estimation at a crime scene can be useful in discerning an event or placing it in time. However, fingerprints are a complex biological matrix with intrinsic and extrinsic variability factors to the donor, being a challenge not only to identify the biochemical components present, but also to understand their aging patterns. For this, the analytical methods guided this research in two reviews: the first selected the classes of methods most used for fingerprint analysis and the second, which biochemical components present in the samples can provide information on the temporal estimation. Regarding the methods classes, mass spectrometry proved to be the most promising technique for fingerprint analysis, highlighting the Matrix Assisted Ionization Desorption (MALDI MS) source as the most used. With this, a MALDI MS method was developed with the application of Chemical Imaging (IMS) which, from the component’s ions selection of major intensity in the spectra, allowed the fingerprints visualization fifty days after their deposition. The second most used methods class were spectroscopy, which are mostly low-cost and non-destructive – when compared to mass spectrometry and provide results in seconds. Thus, a Micro-Fourier Transform Infrared Spectroscopy (μ-FTIR) method was developed with sebaceous fingerprints were monitored and analyzed for one week followed by application of a supervised method of Linear Discriminant Analysis. It was seen that despite the donor profiles being similar, rich in fatty acids from contact contamination, the method allowed for the elaboration of a separation trend between the samples based on the time elapsed since the deposition of the fingerprints. And, additionally, it was possible to segregate the samples by donor. Thus, this work composes a step towards the application of analytical science to Fingerprint Analysis as a foundation resource of justice in the generation of reliable evidence for the search of truth of the facts

Chemometrics in forensic science: Approaches and applications

Forensic investigations are often reliant on physical evidence to reconstruct events surrounding a crime. However, there remains a need for more objective approaches to evidential interpretation, along with rigorously validated procedures for handling, storage and analysis. Chemometrics has been recognised as a powerful tool within forensic science for interpretation and optimisation of analytical procedures. However, careful consideration must be given to factors such as sampling, validation and underpinning study design. This tutorial review aims to provide an accessible overview of chemometric methods within the context of forensic science. The review begins with an overview of selected chemometric techniques, followed by a broad review of studies demonstrating the utility of chemometrics across various forensic disciplines. The tutorial review ends with the discussion of the challenges and emerging trends in this rapidly growing field

Forging a Stable Relationship?: Bridging the Law and Forensic Science Divide in the Academy

The marriage of law and science has most often been represented as discordant. While the law/science divide meme is hardly novel, concerns over the potentially deleterious coupling within the criminal justice system may have reached fever pitch. There is a growing chorus of disapproval addressed to ‘forensic science’, accompanied by the denigration of legal professionals for being unable or unwilling to forge a symbiotic relationship with forensic scientists. The 2009 National Academy of Sciences Report on forensic science heralds the latest call for greater collaboration between ‘law’ and ‘science’, particularly in Higher Education Institutions (HEIs) yet little reaction has been apparent amid law and science faculties. To investigate the potential for interdisciplinary cooperation, the authors received funding for a project: ‘Lowering the Drawbridges: Forensic and Legal Education in the 21st Century’, hoping to stimulate both law and forensic science educators to seek mutually beneficial solutions to common educational problems and build vital connections in the academy. A workshop held in the UK, attended by academics and practitioners from scientific, policing, and legal backgrounds marked the commencement of the project. This paper outlines some of the workshop conclusions to elucidate areas of dissent and consensus, and where further dialogue is required, but aims to strike a note of optimism that the ‘cultural divide’ should not be taken to be so wide as to be beyond the legal and forensic science academy to bridge. The authors seek to demonstrate that legal and forensic science educators can work cooperatively to respond to critics and forge new paths in learning and teaching, creating an opportunity to take stock and enrich our discipline as well as answer critics. As Latham (2010:34) exhorts, we are not interested in turning lawyers into scientists and vice versa, but building a foundation upon which they can build during their professional lives: “Instead of melding the two cultures, we need to establish conditions of cooperation, mutual respect, and mutual reliance between them.” Law and forensic science educators should, and can assist with the building of a mutual understanding between forensic scientists and legal professionals, a significant step on the road to answering calls for the professions to minimise some of the risks associated with the use of forensic science in the criminal process. REFERENCES Latham, S.R. 2010, ‘Law between the cultures: C.P.Snow’s The Two Cultures and the problem of scientific illiteracy in law’ 32 Technology in Society, 31-34. KEYWORDS forensic science education legal education law/science divid

Analysis of Forensically Relevant Evidence Using Electrochemistry, Spectroscopy, and Mass Spectrometry Tools

Forensic science relies on the use of multiple techniques in the assessment of evidence to increase the accuracy and reliability of the results. However, with the rapidly changing drug landscape due to the introduction of novel psychoactive substances, many traditional screening methods are no longer sensitive or selective enough for use. Additionally, many screening methods such as chemical color tests are prone to false positive and negative results and are subjective. Therefore, the goal of this dissertation was to develop a novel analytical scheme that can provide a more efficient, rapid, and sensitive method that will facilitate adoption in the laboratory and onsite in the field. To this end, electrochemistry and Raman spectroscopy were assessed independently for their use in orthogonal testing scenarios, and in tandem via spectroelectrochemical methods to improve both the sensitivity and selectivity of seized drug screening. A panel of 15 drug analytes and 15 diluent compounds comprising some of the most encountered analytes was considered. This panel was characterized via electrochemistry for use as the first tier in investigating a seized substance. Then normal Raman spectroscopy was explored as the second tier in an orthogonal analytical scheme. Both 785 nm and 1064 nm Raman systems were tested with the panel of analytes. The pure compounds were characterized prior to analysis of simulated mixture samples with binary mixtures prepared at 1:4, 1:7, 1:10, and 1:20 ratios. Finally, electrochemistry and Raman spectroscopy were combined into a third-tier technique: time-resolved spectroelectrochemistry. Both targeted and nontargeted electrochemical-surface enhanced Raman spectroscopy method (EC-SERS) was developed. The targeted EC-SERS method provided an analysis approach for fentanyl and fentanyl analogs, while also allowing for in situ generation of a SERS substrate with a silver electrode and simultaneous analysis of the sample. This method demonstrated excellent selectivity and sensitivity with a limit of detection for the most sensitive compound (4-ANPP) of 10 ng/mL. Additionally, differentiation of fentanyl analogs was demonstrated to be achievable. Various potentially interfering compounds were assessed including heroin, cocaine, methamphetamine, caffeine, quinine, and others. Quinine was the only compound observed to have significant interference with fentanyl detection. To demonstrate the fit-for-purpose of this method, authentic seized samples were analyzed from a forensic laboratory including both true fentanyl positive and true fentanyl negative samples. Using GC-MS and LC-MS/MS as ground-truth, an overall accuracy of ~88% was achieved for the detection of fentanyl within the seized samples. More importantly, the power of this EC-SERS screening approach was demonstrated by the accurate identification of fentanyl even in mixtures containing 5 or more compounds. Beyond the problems associated with drugs of abuse and opioid epidemic, another critical area of increasing interest deals with firearms-related crimes. Gun violence in our country results in thousands of deaths each year. However, the discipline of gunshot residue analysis is one of the few areas in forensics that does not have a reliable screening approach. Although the gold standard method utilizes scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS), providing morphological and elemental analysis, the method is time-consuming, expensive, and cannot analyze organic gunshot residues. Therefore, this dissertation also looked at the usefulness of electrochemistry to provide a simple, inexpensive, and portable screening method for the simultaneous analysis of inorganic and organic gunshot residues. Due to the rapid nature of electrochemistry, an extremely large population of over 1,000 authentic sample sets was collected and analyzed. These samples comprised several different subpopulations: leaded shooter, lead-free shooter, mixed leaded and lead-free shooter, low-risk background non-shooter, high-risk background non-shooter, and leaded shooter with post-shooting activities. The low-risk background allowed for the assessment of the presence of gunshot residue analytes in the background population not associated with the discharge of a firearm and provided a statistical analysis of background levels. These critical thresholds were used to define a positive and negative sample and resulted in accuracy values ranging between 75% and 82%. Additionally, due to the large number of samples and large data sets, the usefulness of machine learning approaches, specifically neural networks were investigated for their ability to make use of the data trends and provide more accurate classification of samples. The neural network utilized in this approach provided an overall accuracy of 98%. The use of electrochemistry for the screening of gunshot residues from the hands of individuals provides a rapid, inexpensive, simple, and portable screening approach that can improve investigative leads, improve case triage, and lower backlogs and costs associated with gunshot residues. Additionally, the speed of analysis provides the opportunity for investigators to collect more samples and from other surfaces that may not have been done in the past due to the disadvantages of the current methodologies. This dissertation demonstrates the advantages of employing simple, fast, and portable technologies in the screening of common forensic evidence. Electrochemistry, spectroscopy, and spectroelectrochemistry are powerful techniques that can revolutionize analytical schemes used in forensic science, and this research provides the foundations and a path forward