The use of the LightCycler for the detection of Y chromosome SNPs

A novel methodology based on PCR monitoring on-line with fluorescent formats using the LightCycler for Y chromosome SNP typing is proposed. The main advantages of the system are the time necessary for the analysis (which is around 20 min), the robustness and the accuracy of the method and especially its sensitivity, which permits the detection of the male component in male-female mixtures up to 1:300 for some of the SNPs.Singleplexes of four different SNPs (M9, sY81, SRY-1532 and SRY-2627) as well as two duplexes (M9 and sY81 on the one hand and SRY-1532 and SRY-2627 on the other) were efficiently implemented. A simultaneous amplification and analysis of the four SNPs is also possible. It seems difficult with the current methodology to implement more than a quadruplex.     

Identification process in mass graves from the Spanish Civil War II

The identification process of a mass grave from the Spanish Civil War (1936-1939) is presented. The presumed location of the grave, as well as the presumed number and identities of the persons buried in the grave were obtained exclusively from witnesses' and relatives' testimonies. In agreement with the testimonies, the grave was located at the indicated location and five skeletons were exhumed. Also in agreement with the testimonies, the osteological and DNA study led investigators to propose the identification of two kin groups, a father and his son and a pair of brothers. But the genetic study did not support the identification of a fifth man presumed to have been buried in the grave. The differences and similarities between this case and another case reported earlier are discussed.     

Single‐Image Rectification Technique in Forensic Science

Many researchers have been working in Spain to document the communal graves of those assassinated during the Spanish Civil War. This article shows the results obtained with two low‐cost photogrammetric techniques for the basic documentation of forensic studies. These low‐cost techniques are based on single‐image rectification and the correction of the original photo displacement due to the projection and perspective distortions introduced by the lens of the camera. The capability of image rectification is tested in an excavation in the village of Loma de Montija (Burgos, Spain). The results of both techniques are compared with the more accurate data obtained from a laser scanner system RIEGL LMS‐Z390i to evaluate the error in the lengths. The first technique uses a camera situated on a triangle‐shaped pole at a height of 5 m and the second positions the camera over the grave using a linearly actuated device. The first technique shows measurement errors less than 6%, whereas the second shows greater errors (between 8% and 14%) owing to the positioning of the carbon‐fiber cross on an uneven surface.     

The 2000-2001 GEP-ISFG Collaborative Exercise on mtDNA: assessing the cause of unsuccessful mtDNA PCR amplification of hair shaft samples

We report the results of Spanish and Portuguese working group (GEP) of International Society of Forensic Genetics (ISFG) Collaborative Exercise 2001-2002 on mitochondrial DNA (mtDNA) analysis. 64 laboratories from Spain, Portugal and several Latin-American countries participated in this quality control exercise. Five samples were sent to the participating laboratories, four blood stains (M1-M4) and a sample (M5) consisting of two hair shaft fragments. M4 was non-human (Felis catus) in origin; therefore, the capacity of the labs to identify the biological source of this sample was an integral part of the exercise. Some labs detected the non-human origin of M4 by carrying out immuno-diffussion techniques using antihuman serum, whereas others identified the specific animal origin by testing the sample against a set of animal antibodies or by means of the analysis of mtDNA regions (Cyt-b, 12S, and 16S genes). The results of the other three human blood stains (M1-M3) improved in relation to the last Collaborative Exercises but those related to hairs yielded a low rate of success which clearly contrasts with previous results. As a consequence of this, some labs performed additional analysis showing that the origin of this low efficiency was not the presence of inhibitors, but the low quantity of DNA present in these specific hair samples and the degradation.As a general conclusion the results emphasize the need of external proficiency testing as part of the accreditation procedure for the labs performing mtDNA analysis in forensic casework.     

Automated comparison of firearm bullets

Fired bullets bear striation marks that can be thought of as a "fingerprint" left by the firearm. This new comparison approach is based on an automated extraction of a "signature" encompassing the relevant marks from an image. To this end, multiple pictures of the bullet are recorded first by using different illumination patterns, and a high quality image is generated by means of fusion techniques. After a preprocessing, the image intensities are filtered along the striations direction, yielding a compact representation of the marks. A non-linear filter selects the striae of interest. The actual comparison takes place by cross-correlating the signatures obtained this way. Finally, an assessment strategy is proposed to objectively evaluate the performance of the system. As demonstrated with an image database of real bullets, the proposed approach outperforms a state-of-the-art commercial system.     

Developmental Trajectories of Science Identity Beliefs: Within-Group Differences among Black,Latinx, Asian,and White Students

Journal of Youth and Adolescence - Though adolescents’ science identity beliefs predict positive STEM outcomes, researchers have yet to examine developmental differences within racial/ethnic...     

inhabiting or occupying the web?: virtual communities and feminist cyberactivism in online Spanish feminist theory and praxis

This article examines the relationships between gender and technology in Spanish feminist praxis online and argues that different perspectives on online feminist community-building offer distinct responses to cyberactivism, which is considered central to sustaining efforts for social change. To ascertain whether Spanish virtual communities and cyberactivism have the potential to address the challenges posed by the relations between gender and technology, we analyse feminist scholar Remedios Zafra's theoretical proposals, and the different ways in which this theory intersects with the cyberactivism put forth by two feminist web portals, Ciudad de Mujeres and Mujeres en Red. We will discuss to what degree particular Spanish feminist theory and practice online adapts to or challenges utopianism regarding the liberating potential of technology. We will also examine how, in the face of critical arguments about such liberatory possibilities, two options present themselves for women's effective use of technology: inhabiting or occupying the web through the construction of feminist communities online.