Contramedidas en la suplantación de autoridades de certificación. Certificate pinning

La importancia de asegurar la comunicación entre personas ha crecido a medida que se ha avanzado en la sofisticación y el alcance de los mecanismos provistos para ello. Ahora, en la era digital, el alcance de estas comunicaciones es global y surge la necesidad de confiar en infraestructuras que suplan la imposibilidad de identificar a ambos extremos de la comunicación. Es la infraestructura de autoridades de certificación y la gestión correcta de certificados digitales la que ha facilitado una aproximación más eficiente para cubrir esta demanda. Existen, sin embargo, algunos aspectos de esta infraestructura o de la implementación de algunos de sus mecanismos que pueden ser aprovechados para vulnerar la seguridad que su uso debe garantizar. La presente investigación profundiza en alguno de estos aspectos y analiza la validez de las soluciones propuestas por grandes productores de software frente a escenarios realistas

Machine-Learning based analysis and classification of Android malware signatures

Multi-scanner Antivirus (AV) systems are often used for detecting Android malware since the same piece of software can be checked against multiple different AV engines. However, in many cases the same software application is flagged as malware by few AV engines, and often the signatures provided contradict each other, showing a clear lack of consensus between different AV engines. This work analyzes more than 80 thousand Android applications flagged as malware by at least one AV engine, with a total of almost 260 thousand malware signatures. In the analysis, we identify 41 different malware families, we study their relationships and the relationships between the AV engines involved in such detections, showing that most malware cases belong to either Adware abuse or really dangerous Harmful applications, but some others are unspecified (or Unknown). With the help of Machine Learning and Graph Community Algorithms, we can further combine the different AV detections to classify such Unknown apps into either Adware or Harmful risks, reaching F1-score above 0.84.The authors would like to acknowledge the support of the national project TEXEO (TEC2016-80339-R), funded by the Ministerio de Economia y Competitividad of SPAIN through, and the EU-funded H2020 SMOOTH project, Spain (grant no. H2020-786741). Similarly, the authors would like to remark the support provided by the Tacyt system (https://www.elevenpaths.com/es/te cnologia/tacyt/index.html) for the collection and labeling of AV information. Finally, Ignacio Martin would like to acknowledge the support granted by the Spanish Ministry of education through the FPU scholarship he holds (FPU15/03518)

Amplifying Reactivity of Metal Hydrides: A Heterotrimetallic NiAl2(μ2-H)2 Catalyst for the Facile Dearomatization of N-Heterocycles

Identifying methods to modulate the reactivity of metal-hydrides are lacking yet highly desirable given the role they play in a plethora of catalytic applications. Herein we report novel methodology to amplify reactivity of metal hydrides through the design of well-defined heterometallic bridged hydride species. Catalytic hydroboration of quinolines was dramatically altered by the addition of a secondary metal to bridge the Al-hydride species LAlH. Specifically, the addition of Ni(COD)2 led to the formation of novel heterotrimetallic species 1 which features Ni participating in 3-center- bonding with sterically accessible Al-H species and exhibits catalytic hydroboration of sterically encumbered quinolines and approximately a 400 times enhancement in catalytic reactivity in comparison to LAlH

Assessment of the potential economic impact of the use of AM technologies in the cost levels of manufacturing and stocking of spare part products

Additive manufacturing (AM) technologies are appropriate manufacturing technologies to produce low rotation products of high added value. Products in the spare parts business usually have discontinuous demand levels of reduced numbers of parts. Indeed, spare parts inventories handle myriad of products that require big immobilized investments while having an intrinsic risk of no-use (for example due to obsolescence or spoilage). Based on these issues, the present work analyses the fundamental cost factors in a real case study of a company dedicated to the supply of spare parts for fluid conduction systems. Real inventory data is assessed to determine the product taxonomy and its associated costs. A representative product of the stock is analyzed in detail on original manufacturing costs, in AM costs and then redesigned with topological optimization to reduce the AM cost levels (via design for additive manufacturing). A general equation for cost assessment is formulated. Given the specific data collected from the company, the parameters in this general equation are calculated. Finally, the general equation and the product cost reduction achieved are used to explore the potential economic impact of the use of AM technologies in the cost levels of manufacturing and stocking of spare part products.Postprint (published version

Quantitative analysis of the effects of incorporating laser powder bed fusion manufactured conformal cooling inserts in steel moulds over four types of defects of a commercially produced injected part

The introduction of additively manufactured conformal cooling inserts in steel moulds for plastic injection is becoming a recommended standard. Fine adjustment of the temperatures in the mould has demonstrated potential to reduce cycle times and to increase production volumes. Within this context, the present article explores the historical production data of a commercially produced part, before and after the incorporation of an LPBF conformal cooling insert, to analyse what is the quantitative real effect on the efficiency of the production runs. The article analyses the change in the global rejection rates, and its effect over four different product defect types, i.e.: optical (surface), part integrity (bubbles, transparency, geometry), incomplete fill-in (interior), and breakages during extraction. The results demonstrate a specific decrease on the average appearance (from 20.53% to 13.48%; reduction of 7.05%) and variability (standard deviation from 14.16% to 6.81%; reduction of a 7.35%), of the global scrap rates, and a significant decrease in the scrap rates generated by optical defects and extraction part breakages. The article also characterises the former and the new processes by adjusting two distribution functions (Pareto Type-I and Weibull) and compares different estimates for the global expected scrap rates in past and future production runs.Peer ReviewedPostprint (published version

Propiedades psicométricas de la Escala de Motivación Académica de los Adolescentes (EMAA) en una muestra representativa de estudiantes de instituto de la República Dominicana

Within the growing body of research that has focused on academic success, academic motivation has gathered considerable attention. The aim of this this research is to present the first validation of the Adolescents’ Academic Motivation Scale (AAMS). Total sample was composed by 1712 students of secondary education from two districts in the Dominican Republic. The main measurement outcome was the AAMS. Results from the CFA were satisfactory: χ2(5) = 57.73, p < .001; CFI = .970; RMSEA = .079 [.061, .097], and SRMR = .024. IRT analyses favored the two-parameter logistic model, indicating that items were not equally discriminant. Structural Equation Model with latent variables in which academic motivation was a significant predictor of grades resulted in excellent fit: χ2(53) = 182.76, p < .001; CFI = .980; RMSEA = .038 90% CI [.032, .044], and SRMR = .025. In sum, this work presents an exhaustive psychometric analysis of the AAMS in a representative sample of high school Dominican students.Entre el creciente cuerpo de investigación que se ha centrado en el éxito académico, la motivación académica ha captado considerable atención. El objetivo de esta investigación es presentar la primera validación de la Escala de Motivación Académica de los Adolescentes (EMAA). La muestra total estuvo compuesta por 1712 estudiantes de secundaria de dos distritos de la República Dominicana. La medida principal fue la EMAA. Los resultados del AFC fueron satisfactorios: χ2(5) = 57.73, p < .001; CFI = .970; RMSEA = .079, 90% CI [.061, .097], y SRMR = .024. Los análisis de TRI favorecieron al modelo logístico de dos parámetros, indicando que los ítems no fueron igualmente discriminativos. El Modelo de Ecuaciones Estructurales en el que la motivación académica predecía de forma estadísticamente significativa las calificaciones obtuvo un ajuste excelente: χ2(53) = 182.76, p < .001; CFI = .980; RMSEA = .038 [.032, .044], and SRMR = .025. En resumen, este trabajo presenta un exhaustivo análisis psicométrico de la EMAA en una muestra representativa de estudiantes dominicanos de instituto

Protection of Strawberry Plants against Charcoal Rot Disease (Macrophomina phaseolina) Induced by Azospirillum brasilense

Some Plant Growth-Promoting Rhizobacteria (PGPR) can induce protection against pathogens, increasing plant tolerance to various diseases. This so-called biocontrol activity is replacing harmful practices in agriculture caused by the use of agrochemicals. Azospirillum brasilense is one of the PGPR already effectively used as a resistance inducer in several crops. The aim of this study was to evaluate the protective effect of PGPR A. brasilense strains isolated from strawberry and petunia plants (REC3, 2A1, 2A2, and 2E1) against the fungal pathogen Macrophomina phaseolina, which is the causal agent of the strawberry charcoal rot disease. In vitro antagonism assays and enzymatic tests on Petri dishes revealed no direct inhibition on M. phaseolina growth by any of the A. brasilense strains. However, strawberry plants treated with REC3 and 2A1 strains increased callose and lignin deposition and stomatal closure compared to untreated plants. In addition, treatments with either bacterial strains induced a defense response in strawberry plants against virulent isolates of M. phaseolina evidenced by an increased tolerance to the charcoal rot disease. These results suggest that A. brasilense REC3 and 2A1 strains can be used for the activation of innate immunity in strawberry plants as a strategy for managing charcoal rot in a sustainable and environmentally friendly way.EEA FamailláFil: Viejobueno, Josefina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Albornoz, Patricia Liliana. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales; ArgentinaFil: Albornoz, Patricia Liliana. Fundación Miguel Lillo; ArgentinaFil: Camacho, María. Instituto de Investigación y Formación Agraria y Pesquera; EspañaFil: Santos, Berta de los. Instituto de Investigación y Formación Agraria y Pesquera; EspañaFil: Martinez Zamora, Martin Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Martinez Zamora, Martin Gustavo. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Salazar, Sergio Miguel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Salazar, Sergio Miguel. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentin

Caracterización de bacterias promotoras de crecimiento vegetal (BPCV) nativas y su efecto en el desarrollo del maíz (Zea Mays L.)

Maize (Zea mays L.) is one of the most important cereals for Mexico and humanity. The Yaqui Valley -located in the northwest of Mexico- is one of the most important agricultural regions worldwide, it is characterized by an indiscriminate use of inorganic fertilizers for improving crop yields, leading to an increased environmental and economic cost of maize production. Here, a morphological, metabolic, and molecular characterization of native bacteria associated with maize rhizosphere was carried out, and then positive effects of bacterial inoculation to plants under greenhouse conditions were evaluated. The evaluated strains were taxonomically affiliated –based on the 16S rRNA gene- as Bacillus sp. (13B41), Advenella incenata (22A67), Pantoea dispersa (22B45), and Rhizobium pusense (31B11). All of these strains were able to synthesize indoles, produce siderophores, and solubilize phosphates. The individual inoculation of these strains to maize plants showed a significant increment (compared to un-inoculated plants) in height (35-40 %), shoot dry weight (244-289 %), root dry weight (99-137 %), and SPAD values (40- 47 %). The native bacteria associated with maize in the Yaqui Valley are a promising alternative to promote the growth of their host plant, and contribute to a sustainable maize production.El maíz (Zea mays L.) es uno de los cereales más importantes para México y la humanidad. El Valle del Yaqui -ubicado en el noroeste de México- es una de las regiones agrícolas más importantes a nivel mundial, se caracteriza por un uso indiscriminado de fertilizantes inorgánicos para mejorar el rendimiento de los cultivos, lo que genera un mayor costo ambiental y económico de la producción de maíz. En este trabajo se realizó una caracterización morfológica, metabólica y molecular de bacterias nativas asociadas a la rizósfera del maíz y se evaluaron los efectos positivos de la inoculación bacteriana en plantas de maíz bajo condiciones de invernadero. Basándose en la secuencia del gen del 16S ARNr las cepas evaluadas se afiliaron taxonómicamente como Bacillus sp. (13B41), Advenella incenata (22A67), Pantoea dispersa (22B45) y Rhizobium pusense (31B11). Todas estas cepas pudieron sintetizar indoles, producir sideróforos y solubilizar fosfatos. La inoculación individual de estas cepas en maíz mostró un incremento significativo (en comparación con plantas no inoculadas) en altura (35-40 %), peso seco de brotes (244-289 %), peso seco de raíces (99-137 %) y valores SPAD (40-47%). Las bacterias asociadas al maíz nativas del Valle del Yaqui son una alternativa prometedora para promover el crecimiento de su planta hospedante y contribuir a una producción de maíz sostenible

Recent developments in the application of plant growth-promoting drought adaptive rhizobacteria for drought mitigation

Drought intensity that has increased as a result of human activity and global warming poses a serious danger to agricultural output. The demand for ecologically friendly solutions to ensure the security of the world’s food supply has increased as a result. Plant growth-promoting rhizobacteria (PGPR) treatment may be advantageous in this situation. PGPR guarantees the survival of the plant during a drought through a variety of processes including osmotic adjustments, improved phytohormone synthesis, and antioxidant activity, among others and these mechanisms also promote the plant’s development. In addition, new developments in omics technology have improved our understanding of PGPR, which makes it easier to investigate the genes involved in colonizing plant tissue. Therefore, this review addresses the mechanisms of PGPR in drought stress resistance to summarize the most current omics-based and molecular methodologies for exploring the function of drought-responsive genes. The study discusses a detailed mechanistic approach, PGPR-based bioinoculant design, and a potential roadmap for enhancing their efficacy in combating drought stress