A study on the false positive rate of Stegdetect

In this paper we analyse Stegdetect, one of the well-known image steganalysis tools, to study its false positive rate. In doing so, we process more than 40,000 images randomly downloaded from the Internet using Google images, together with 25,000 images from the ASIRRA (Animal Species Image Recognition for Restricting Access) public corpus. The aim of this study is to help digital forensic analysts, aiming to study a large number of image files during an investigation, to better understand the capabilities and the limitations of steganalysis tools like Stegdetect. The results obtained show that the rate of false positives generated by Stegdetect depends highly on the chosen sensitivity value, and it is generally quite high. This should support the forensic expert to have better interpretation in their results, and taking the false positive rates into consideration. Additionally, we have provided a detailed statistical analysis for the obtained results to study the difference in detection between selected groups, close groups and different groups of images. This method can be applied to any steganalysis tool, which gives the analyst a better understanding of the detection results, especially when he has no prior information about the false positive rate of the tool.     

Regionalisation of higher education services in Europe and East Asia and potential for global change

International provision of higher education services in both European and East Asian countries increasingly have a regional dimension. The European Union has since 1987 promoted the mobility of students, faculty, and content through its Erasmus Programmes. The ‘Bologna’ process that began in 1998/1999 now brings over 40 European countries together to create a European Higher Education Area by the end of the current decade. Meanwhile, East Asian countries (10 in ASEAN, plus P.R. China, Japan and South Korea) are also in a process of internationalising their higher education sector with an increasing regional component. Led by Japan, the “ASEAN+3 study group on facilitation and promotion of exchange of people and human resource development” advanced a comprehensive report, welcomed by the East Asian leaders meeting in October 2003, that strives for regional promotion of lifelong learning programs; credit transfer systems; scholarships and exchange programs for students, faculty, staff; research and development cooperation; ‘centres of excellence’ including e-learning; and curricular development as bases for common regional qualification standards among interested institutions. Both regional processes could reinforce each other in various ways, but possibly chiefly through the Asia–Europe Meeting (ASEM) process, unique among various recent inter-regional dialogue and cooperation processes around the world. Moreover, European and East Asian converging higher education processes could help the rest of the world through world inter-regionalism, and through an overhaul of international organisations dealing with higher education. This research was mainly funded by a grant from the Spanish Ministry of Education, Secretary of State for Universities and Research, cofinanced by the European Social Fund. A research fellowship from the Japan Foundation’s Japanese Studies and Intellectual Exchange Department is also kindly acknowledged.

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Genetic admixture and diversity estimations in the Mexican Mestizo population from Mexico City using 15 STR polymorphic markers

The 15 AmpFlSTR Identifiler loci D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA were analyzed in a sample of 378 unrelated individuals from Mexico City, Mexico. Significant deviations from HW equilibrium in 14/15 STR loci alleles were not detected. The D18S51 locus had the highest power of discrimination (0.970). Genetic admixture estimations revealed a 69% of Amerindian, 26% of European and 5% of African contribution. Comparative analyses between Mexicans and other neighboring populations reveal significant differences in genetic diversity. Our results are important for future comparative genetic studies in different Latin American ethnic groups, particularly Mexican Mestizos and Amerindians. They should also be helpful in genetics, population evolution, forensic and paternity testing.     

Color Stability of Dental Restorative Materials Submitted to Heat Sources,for Forensic Purposes

During postmortem examination of the dental arches of carbonized victims, dental restorative materials may be found. The aim of this study was to evaluate the effect of heat source action on the color stability of composite resin (CR) and glass ionomer cement (GIC) restorations, to discriminate between them and compare with antemortem dental data. Sixty bovine teeth (30 CR and 30 GIC) were prepared (6 × 6 × 2 mm) and separated into groups (n = 10). The color readouts were taken by spectrophotometer, before and after heat action (100°C, 200°C, 300°C), in an oven for 15 min. There were color alterations for all coordinates (ΔE, ΔL*, Δa* eΔb*) for both materials. GIC presented greater change. The authors concluded that it is possible to distinguish between the materials by the color changes analyzed by instrumental method, helping victim identification.     

Post-mortem analysis of formic acid disposition in acute methanol intoxication

Fifteen cases of fatal massive methanol intoxication have been investigated. Victims received either no treatment or ethanol therapeutic treatment. Methanol poisoning cases were classified in three groups according to survival time: more than 3 days (group 1), up to 3 days (group 2) and few hours (group 3). Body distribution of methanol and formic acid, as the main metabolite, was analyzed in blood and in different organs (brain, kidney, lung and liver). Relationships between formic acid concentration in the different tissues, survival time and type of treatment applied to victims were studied. Formic acid in blood and tissues was analyzed by head space gas chromatography (head space-GC) with FID detector, previous transformation in methyl formate, essentially as described by Abolin. Formic acid concentration was between 0.03 and 1.10g/l in the samples under study. A good correlation between blood and brain, but poor between blood and the remaining tissues was found. Obtained data suggested that the use of blood and brain could help to improve the analysis of formic acid intoxication. The best correlation among organs was found between lung and kidney for all groups (r(2)=0.91, 0.84 and 0.87, corresponding to groups 1, 2 and 3, respectively). Lethality index was defined as LI = (concentration of formic acid in blood in (g/l)/0.5) x 100, taking into account that 0.5g/l is the concentration reported by Mahieu in severe methanol poisoning. LI parameter was used to estimate formic acid incidence on the lethality of methanol poisoning cases. LI showed a good correlation with total formic acid concentration of the different tissues analyzed (r(2)=0.80). Furthermore, LI allowed us to discriminate between individuals that received therapeutic treatment and survived different periods. LI>100 indicated a severe intoxication and short survival time if the victim was assisted with ethanol therapy and hemodialysis was not applied. With regard to victims who received no therapeutic treatment and died in few hours, LI was in the range 40-100. LI was below 40 for individuals that survived more than 3 days and hemodialysis was not performed. Results showed the importance of performing formic acid analysis to diagnose severe methanol intoxication in post-mortem cases.     

Identifying the cutoff score for the PCL-R scale (psychopathy checklist-revised) in a Brazilian forensic population

This study introduces a Portuguese-language version of psychopathy checklist-revised (PCL-R) [Harv. Mental Health Lett. 12 (1995) 4] in the Brazilian penitentiary system. Hare's scale is used extensively in many other countries. In a forensic population sample of 56 male subjects classified as psychopaths and non-psychopaths [Manual for the Hare Psychopathy Checklist-Revised, Multi-Health System, Toronto, 1991], 33 correlated to global personality disorder (GPD) and 23 to partial personality disorder (PPD), respectively, subtypes of antisocial personality disorder [Manual for the Hare Psychopathy Checklist-Revised, Multi-Health System, Toronto, 1991]. Subjects were evaluated through psychiatric and neurological examinations, review of judicial records, Rorschach and PCL-R. A control group of 30 subjects without criminological or psychiatric history was also evaluated with the same instruments. PCL-R validation and identification of cutoff score for Psychopathy (GPD group) was assessed through the concurrent use of the Rorschach. PCL-R cutoff score for the Brazilian population was set at 23. Sensitivity was determined at 84.8%, and reliability was high (Kappa index = 0.87). GPD individuals were characterized as clearly psychopathic according to PCL-R criteria while PPD individuals can only be considered mildly psychopathic, with better chance of rehabilitation.     

Fragmentation of Power and the Emergence of an Effective Judiciary in Mexico, 1994–2002

Legal reforms that make judges independent from political pressures and empower them with judicial review do not make an effective judiciary. Something has to fill the gap between institutional design and effectiveness. When the executive and legislative powers react to an objectionable judicial decision, the judiciary may be weak and deferential; but coordination difficulties between the elected branches can loosen the constraints on courts. This article argues that the fragmentation of political power can enable a judiciary to rule against power holders' interests without being systematically challenged or ignored. This argument is tested with an analysis of the Mexican Supreme Court decisions against the PRI on constitutional cases from 1994 to 2002. The probability of the court's voting against the PRI increased as the PRI lost the majority in the Chamber of Deputies in 1997 and the presidency in 2000.     

Effectiveness of selective credit controls: An empirical test applied to India

This article examines the efficiency of the selective credit policies pursued by the Indian authorities aimed at curtailing inventory accumulation in the sugar industry. Based on the relationship between investment demand and credit availability, a methodology is developed to test the degree of substitutability of different types of credit in the inventory decision of the firm. The tests conducted indicate that the credit policies adopted by Indian authorities have been of limited effectiveness owing to the substitutability of the different sources of finance. The results also indicate that while a correctly designed selective credit policy can affect inventory accumulation, the same policy may have an adverse impact on overall investment of the firm.