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GMA welding process stability and robustness, as well as weld quality, depend strongly on metal transfer behavior. Evaluating in detail the phenomenon of droplet transfer, considering the detachment of metal from the tip of the electrode until it reaches the weld pool and considering the forces acting in the process, is a field of great interest for those looking to control these parameters to achieve the desired characteristics in welding. Currently, there are better high-speed filming systems, which allow the acquisition of better-quality images and open the possibility for the application of computer vision algorithms with the aim of better understanding the dynamics of the metallic transfer. The objective of this research was to develop an algorithm that allows the detection of metal droplets in the footage of the metal transfer process. For this, exploratory work performed an algorithm that managed to detect the drops with high precision. Several methods using findContours, Canny, Laplacian, Sobel, and a weightless neural model were adapted and compared in the detection and measurement of the projected areas, as well as with regard to the processing times. The results generated by the algorithm allowed the detection and monitoring of the metal transferred in the form of drops, as well as the calculation of the projected area and the displacement, allowing for a better understanding of the metal transfer phenomena and, consequently, future conceptions of welding manufacturing control methods.

En la historiografía de tema mexicano las interpretaciones de lo que ha significado constitucional y políticamente estado de excepción se han suscitado a partir de una base empírica no consolidada. Este artículo reconoce tal debilidad y avanza en una actualización gnoseológica e historiográfica del estado de excepción, que recibió la denominación de suspensión de garantías en las constituciones de 1857 y 1917. El artículo discute las debilidades de la historiografía en el estudio de la figura durante el liberalismo histórico, los intentos de suspender garantías de tres presidentes de la postrevolución (Carranza, Obregón y Ávila Camacho) y los sucedáneos de la suspensión de garantías en la legislación secundaria; en concreto se estudia la figura penal de disolución social, a partir de su instauración en 1941, pasando por la reforma en 1950 y llegando a su derogación en 1970, esta última como uno de los saldos del movimiento estudiantil de 1968. In the historiography of the state of exception in Mexico, interpreta­tions on its constitutional and political meaning have been based on an empirical foundation that has not been consolidated. This article acknowledges this weakness and works toward a gnoseological and historiographical revision of the state of exception, which was called the “suspension of guarantees” in the 1857 and 1917 constitutions. It discusses the weaknesses of the historiography when studying this phenomenon during the period of historic liberalism, the attempts to suspend guarantees by three postrevolutionary presidents (Carranza, Obregón and Ávila Camacho) and substitutes for the suspension of guarantees in secondary legislation, particularly the law on social dissolution, from its approval in 1941, the 1950 reform and its repeal in 1970, which occurred as a consequence of the 1968 student movement.

El presente estudio aborda la participación de mujeres en los movimientos armados clandestinos mexicanos en la década de 1970, durante la llamada “Guerra Sucia”. Se estima la proporción de mujeres involucradas en las organizaciones clandestinas y se ofrecen puntos de comparación con otras experiencias del mismo periodo. Se establecen los orígenes geográficos y la escolaridad de las mujeres que optaron por la clandestinidad y la vía armada. Finalmente se presentan los números y proporciones de mujeres en las organizaciones armadas clandestinas más importantes. Los tres enfoques se acompañan de historias personales y la manera como éstas engarzan con los cálculos. Dos problemáticas son punto de partida del análisis: la discusión académica sobre la participación de mujeres en la violencia política moderna, y el impacto de la urbanización y aculturación acelerada en la creación de condiciones para esa violencia. This article addresses the participation of women in underground ar­med movements in the 1970s, during the so-called dirty war. It offers an estimate of the proportion of women involved in clandestine orga­nizations and offers points of comparison with other experiences in this same period. It establishes the geographic origins and educational level of the women who took the path of the armed underground and presents the numbers and proportions of women in the most impor­tant clandestine organizations. These three approaches are accompa­nied by personal stories and the way in which they are linked to these calculations. Two problems involve the analytical starting point: the academic discussion on women’s participation in modern political violence and the impact of accelerated urbanization and acculturation on the creation of the conditions for this violence.

Pathogenic CAG (cytosine-adenine-guanine) expansions beyond certain thresholds in the ataxin-2 (ATXN2) gene cause spinocerebellar ataxia type 2 (SCA2) and were shown to contribute to Parkinson disease, amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Regulation of ATXN2 gene expression and the function of the protein product are not known. SCA2 exhibits an inverse correlation between the size of the CAG repeat and the age at disease onset. However, a wide range of age at onset are typically observed, with CAG repeat number alone explaining only partly this variability. In this study, we explored the hypothesis that ATXN2 levels could be controlled by DNA methylation and that the derangement of this control may lead to escalation of disease severity and influencing the age at onset. We found that CpG methylation in human ATXN2 gene promoter is associated with pathogenic CAG expansions in SCA2 patients. Different levels of methylation in a SCA2 pedigree without an intergenerational CAG repeat instability caused the disease anticipation in a SCA2 family. DNA methylation also influenced the disease onset in SCA2 homozygotes and SCA3 patients. In conclusion, our study points to a novel regulatory mechanism of ATXN2 expression involving an epigenetic event resulting in differential disease course in SCA2 patients.

Artificial Intelligence (Al) is transforming higher education, bringing challenges and opportunities. Thus, instilling skills to leverage Al effectively and equip students for the future workforce is crucial. This requires a shift from traditional pedagogical methods toward active learning emphasizing problem-solving, collaborative work, and the integration of Al tools. The proposed Active Learning Plan (ALP) addresses these imperatives. This plan encompasses research, problem-solving, pseudocode validation using Al tools such as ChatGPT, thorough code documentation, group collaboration, and evaluation. The ALP delves into the interplay between Al and higher education, and it challenges students to derive manual solutions, draft pseudocode, document it, and subsequently validate it through ChatGPT. Moreover, it fosters collaboration by encouraging the formation of groups of five to craft questionnaires on the core topic, which are later used for learning assessment. It is paramount for students to reflect on their experience, pinpointing strengths, weaknesses, and areas for improvement. The adopted methodology emphasizes problem-solving and collaboration and allows students to engage with cutting-edge technologies, acquiring pivotal skills. The assessment of this approach was based on the Cronbach's alpha coefficient, yielding a value of 1.99016, indicating significant internal consistency. Upon analyzing the outcomes, 74% surpassed the score of 4.1, 18% passed, and only 8% failed to meet the minimum requirement. The deployment of this ALP proves to be an efficient instrument in readying students for an everevolving job market.

The gas metal arc welding-pulsed (GMAW-P) process shows potential for advancing metal additive manufacturing, offering benefits such as high deposition rates, cost-effectiveness, and improved control over heat input and the melt pool. Since droplet detachment modes are crucial to the stability and quality of the additive process, this study mapped three key detachment regions—one drop per pulse (ODPP), multiple drops per pulse (ODPP +), and one drop per multiple pulses (ODPP-)—for stainless steel 308L to assist in parameter selection. By analyzing variations in peak time and peak current with high-speed imaging, intervals for each detachment mode were determined based on the relationship Ip 2  × tp =  D , where D is the detachment constant. The results revealed distinct conditions for each detachment mode, with the detachment constant serving as a reliable predictor of droplet behavior under consistent conditions of wire type, shielding gas, and contact-tip-to-work distance. These findings contribute valuable references for optimizing parameters in GMAW-based additive manufacturing processes.

Background Animal coloration is usually an adaptive attribute, under strong local selection pressures and often diversified among species or populations. The strawberry poison frog ( Oophaga pumilio ) shows an impressive array of color morphs across its distribution in Central America. Here we quantify gene expression and genetic variation to identify candidate genes involved in generating divergence in coloration between populations of red, green and blue O. pumilio from the Bocas del Toro archipelago in Panama. Results We generated a high quality non-redundant reference transcriptome by mapping the products of genome-guided and de novo transcriptome assemblies onto a re-scaffolded draft genome of O. pumilio . We then measured gene expression in individuals of the three color phenotypes and identified color-associated candidate genes by comparing differential expression results against a list of a priori gene sets for five different functional categories of coloration – pteridine synthesis, carotenoid synthesis, melanin synthesis, iridophore pathways (structural coloration), and chromatophore development. We found 68 candidate coloration loci with significant expression differences among the color phenotypes. Notable upregulated examples include pteridine synthesis genes spr , xdh and pts (in red and green frogs); carotenoid metabolism genes bco2 (in blue frogs), scarb1 (in red frogs), and guanine metabolism gene psat1 (in blue frogs). We detected significantly higher expression of the pteridine synthesis gene set in red and green frogs versus blue frogs. In addition to gene expression differences, we identified 370 outlier SNPs on 162 annotated genes showing signatures of diversifying selection, including eight pigmentation-associated genes. Conclusions Gene expression in the skin of the three populations of frogs with differing coloration is highly divergent. The strong signal of differential expression in pteridine genes is consistent with a major role of these genes in generating the coloration differences among the three morphs. However, the finding of differentially expressed genes across pathways and functional categories suggests that multiple mechanisms are responsible for the coloration differences, likely involving both pigmentary and structural coloration. In addition to regulatory differences, we found potential evidence of differential selection acting at the protein sequence level in several color-associated loci, which could contribute to the color polymorphism.

Endangered animals suffer from isolation of their habitats. Isolation leads to a reduction in population size as well as a decrease in genetic diversity and a concomitant increase in the risk of extinction. Amphibians are the most endangered vertebrate class. Besides habitat loss, fragmentation and isolation, amphibians are threatened by emerging diseases e.g., chytrid fungus or Ranavirus. By employing experiments, researchers investigate whether changes in genetic diversity within or among isolated populations affect amphibian fitness. While genetic diversity estimates are based on molecular markers, typically microsatellites, fitness is mostly measured as tadpole performance in rearing experiments often under varying environmental conditions. Tadpole performances (e.g., body mass, growth rate and survival) have been found to be negatively affected by low genetic diversity, as several studies have found a positive association between genetic diversity and these fitness traits. Moreover, infection with pathogens also seems to be more likely in individuals or populations with lower genetic diversity. Overall, these genetic–fitness correlations seem to be more pronounced or detectable in smaller, declining populations but not in larger populations. Genomic studies, which sample a larger fraction of the genome, are still scarce in the conservation genetic literature on amphibians. These are likely to increase in upcoming years and may reveal adaptive variants that protect against dangerous pathogens or environmental changes. Altogether, genetic–fitness correlation studies should be a priority in order to develop effective management plans for the genetic rescue of isolated, imperilled amphibian populations.