Microstructural Characterization and Corrosion Behavior of Similar and Dissimilar Welded Advanced High-Strength Steels (AHSS) by Rotary Friction Welding.

Advanced high-strength steels (AHSSs) are designed for meeting strict requirements, especially in the automotive industry, as a means to directly influence the reduction in the carbon footprint. As rotary friction welding (RFW) has many important advantages over other welding technologies, it plays an important role in the automotive sector. On the above basis, in this work, combinations of the first (complex phase (CP)), second (TWIP (TW)), and third (quenched and partitioned (Q&P)) generations of similar and dissimilar high-alloyed advanced steels have been joined by the RFW process. Having a specific microstructure, rods of CP/CP, Q&P/Q&P, CP/TW, and Q&P/TW steels were welded by employing a homemade adaptation machine under fixed parameters. Microstructural characterization has allowed us to corroborate the metallic bonding of all the tested advanced steels and to identify the different zones formed after welding. Results indicate that the welding zone widens in the center of the workpiece, and under the current friction action, the intermixing region shows the redistribution of solute elements, mostly in the dissimilarly welded steels. Furthermore, because of their complex chemistry and the different mechanical properties of the used steels, dissimilarly welded steels present the most noticeable differences in hardness. The TWIP steel has the lower hardness values, whilst the CP and Q&P steels have the higher ones. As a direct effect of the viscoplastic behavior of the steels established by the thermomechanical processing, interlayers and oxidation products were identified, as well as some typical RFW defects. The electrochemical response of the welded steels has shown that the compositional and microstructural condition mostly affect the corrosion trend. This means that the dissimilarly welded steels are more susceptible to corrosion, especially at the TWIP-steel interface, which is attributed to the energy that is stored in the distorted microstructure of each steel plate as a consequence of the thermomechanical processing during RFW.

Growing up in a crowd: social environment shapes the offspring's early exploratory phenotype in a colonial breeding species.

In colonial breeding species, the number of adverse social interactions during early life typically varies with breeding density. Phenotypic plasticity can help deal with this social context, by allowing offspring to adjust their behaviour. Furthermore, offspring may not be unprepared since mothers can allocate resources to their embryos that may pre-adjust them to the post-hatching conditions. Thus, we hypothesize that lesser black-backed gull chicks raised in dense breeding areas, with greater exposure to intra-specific aggression, show higher levels of anxiety and lower levels of exploration compared to chicks in low-density areas, and that this is facilitated by prenatal effects. To test this, we cross-fostered clutches within and across pre-defined high- and low-breeding density areas. We measured chicks' anxiety and exploration activity in an open-field test that included a novel and a familiar object. We found that both pre- and post-natal social environment contributed nearly equally and shaped the offspring's exploratory behaviour, but not its anxiety, in an additive way. Post-natal effects could reflect a learned avoidance of intra-specific aggression, yet identifying the pathways of the prenatal effects will require further study.

Smell of green leaf volatiles attracts white storks to freshly cut meadows.

Finding food is perhaps the most important task for all animals. Birds often show up unexpectedly at novel food sources such as freshly tilled fields or mown meadows. Here we test whether wild European white storks primarily use visual, social, auditory or olfactory information to find freshly cut farm pastures where insects and rodents abound. Aerial observations of an entire local stork population documented that birds could not have become aware of a mown field through auditory, visual or social information. Only birds within a 75° downwind cone over 0.4-16.6 km approached any mown field. Placing freshly cut grass from elsewhere on selected unmown fields elicited similarly immediate stork approaches. Furthermore, uncut fields that were sprayed with a green leaf volatile organic compound mix ((Z)-3-hexenal, (Z)-3-hexenol, hexenyl acetate), the smell of freshly cut grass, immediately attracted storks. The use of long-distance olfactory information for finding food may be common in birds, contrary to current perception.

Overland and oversea migration of white storks through the water barriers of the straits of Gibraltar.

Soaring landbirds typically exploit atmospheric uplift as they fly overland, displaying a highly effective energy-saving locomotion. However, large water bodies lack thermal updrafts, potentially becoming ecological barriers that hamper migration. Here we assessed the effects of a sea surface on the migratory performance of GPS-tagged white storks (Ciconia ciconia) before, during and after they crossed the straits of Gibraltar. Oversea movements involved only flapping and gliding and were faster, traversed in straighter, descending trajectories and resulted in higher movement-related energy expenditure levels than overland, supporting the water barrier hypothesis. Overland movements at both sides of the sea straits resulted in tortuous routes and ascending trajectories with pre-crossing flights showing higher elevations and more tortuous routes than post-crossing, thus supporting the barrier negotiation hypothesis. Individual positions at both ends of the sea narrow were predicted by zonal winds and storks´ location at entry in the European hinterland, and birds did not show compensational movements overland in anticipation to subsequent wind displacements oversea. The length of the water narrow at departure shore, the elevation therein and the winds on route affected major components of sea crossing performance (such as distances and times overwater, minimum elevations, climb angles, speeds and energy expenditure), supporting the departure position and oversea winds hypotheses. In summary, our study provides a prime example at high temporal resolution of how birds adjust their behavior and physiology as they interact with the changing conditions of the travelling medium, reallocating resources and modifying their movement to overcome an ecological barrier.

Assessment of the sustainability of dual-purpose farms by the IDEA method in the subtropical area of central Mexico.

The objective of this study was to assess the sustainability of 10 dual-purpose cattle farms in a subtropical area of central Mexico. The IDEA method (Indicateurs de Durabilité des Exploitations Agricoles) was applied, which includes the agroecological, socio-territorial and economic scales (scores from 0 to 100 points per scale). A sample of 47 farms from a total of 91 registered in the local livestock growers association was analysed with principal component analysis and cluster analysis. From results, 10 farms were selected for the in-depth study herein reported, being the selection criterion continuous milk production throughout the year. Farms had a score of 88 and 86 points for the agroecological scale in the rainy and dry seasons. In the socio-territorial scale, scores were 73 points for both seasons, being the component of employment and services the strongest. Scores for the economic scale were 64 and 56 points for the rainy and dry seasons, respectively, when no economic cost for family labour is charged, which decreases to 59 and 45 points when an opportunity cost for family labour is considered. Dual-purpose farms in the subtropical area of central Mexico have a medium sustainability, with the economic scale being the limiting factor, and an area of opportunity.

Electrochemical behaviour of new dimeric esters and amides derived from caffeic acid in dimethylsulfoxide.

The electrochemical oxidation in DMSO of four new derivatives of caffeic acid (CA), two dimeric amides and two dimeric esters, is reported in this article. Although all of them contain two caffeoyl electroactive moieties in their structures, small differences in the connectors result in interesting changes in the electrochemical behaviour of this type of compound. Voltammograms of both esters do not show appreciable differences between them; however, an electrografting process occurs during the electrochemical oxidation of one of them, which suggests that the identity of the connector has an influence on the ability of the diesters to interact with the electrode surface. On the other hand, voltammograms of dimeric amides were more complex than those corresponding to dimeric esters. Electronic effects of diamine connectors seem to be related to the fact that caffeoyl moieties suffer from separate oxidation processes in both compounds. In contrast to their ferulic acid (FA) analogues, which have been studied by our group before, CA dimeric amides do not interact in an appreciable way with the electrode surface. In addition, a relationship between the oxidation potential and the inhibition percentage of the DPPH (2,2'-diphenyl-1-picrylhydrazyl) radical was not observed for the symmetrical CA derivatives studied here. However, the molecular flexibility seems to play a very important role in the Free Radical Scavenging Activity (FRSA) of this type of compound.

Factores de riesgo para fracturas en mujeres mayores de 60 años / Risks factors for fractures in women older than 60 years old

Introducción: Doscientos millones de mujeres, de más de sesenta años padecen secuelas de fracturas asociadas a factores de riesgo como tabaquismo, sedentarismo y multiparidad, para el año 2050 una de cada dos fracturas se presentará con asociación de los factores mencionados. Objetivo: Determinar la asociación de tabaquismo, sedentarismo y multiparidad con la presencia o no de fractura. Metodología: Estudio analítico, transversal, retrospectivo. En 200 pacientes mayores de 60 años con y sin fractura actual o antigua, corroborada por radiografía y/o registro en el expediente clínico, sin datos de patología agregada de osteogénesis imperfecta, hipoparatiroidismo, insuficiencia renal y Síndrome de Cushing. Se aplicó cuestionario previamente validado. Resultados: Se analizaron doscientas pacientes (n), cien con fractura y cien sin fractura. Respecto a los factores, se buscan riesgos relacionados con presencia de fractura o no. Para tabaquismo y sedentarismo OR=1.8, multiparidad OR=1.3 veces más riesgo de presentar fractura y a través de la Prueba exacta de Fisher se demostró asociación media para tabaquismo y sedentarismo (r=0.6) y baja para multiparidad (r=0.3). Conclusiones: El presente estudio cumple con el objetivo de identificar la asociación de tabaquismo, sedentarismo y multiparidad como factores de riesgo para fractura y propone acciones de prevención en toda la población femenina sin importar su edad.

Introduction: Two hundred millions of women older than sixty years old suffer sequels of fractures associated to risk factors, such as smoking, sedentary life, and multiple deliveries. By 2050, one in two fractures will show up with association to the mentioned factors. Objective: To determine the association of smoking, sedentary life, and multiple deliveries, and whether the occurrence or not of fracture. Methodology: Analytical, transversal, and retrospective study. A questionnaire previously validated was applied to 200 patients older than 60 years old and with or without current or old fracture, corroborated by X-ray and/or record in medical chart; without data of aggregated pathology of imperfect osteogenesis, hypoparathyroidism, renal insufficiency, and Cushing Syndrome. Results: A total 200 patients (n) were analyzed; 100 with fracture and 100 without it. Regarding the risk factors; they are intended to be related (OR) with presence of fracture or not. For smoking and sedentarism OR=1.8; multiple deliveries OR=1.3 times more at risk of suffering fracture, and through the Fisher's Exact Test, it was demonstrated medium association for smoking and sedentarism (r=0.6) and low for multiple deliveries (r=0.3). Conclusions: The current study accomplishes the objective of identifying association of smoking, sedentarism, and multiple deliveries as risk factors for fracture; and proposes prevention measurements in the whole female population regardless their age.