Elastic properties of carbon nanotubes and their heterojunctions

Comprehensive studies on the modelling and numerical simulation of the mechanical behaviour under tension, bending and torsion of single-walled carbon nanotubes and their heterojunctions are performed. It is proposed to deduce the mechanical properties of the carbon nanotubes heterojunctions from the knowledge of the mechanical properties of the single-walled carbon nanotubes, which are their constituent key unit

Effects of Embryonic Exposure to Salinity Stress or Hypoxia on Post-metamorphic Growth and Survival of the Polychaete Capitella teleta

Although a good number of studies have investigated the impact of larval experience on aspects of post-metamorphic performance, only a few have considered the potential impact of stresses experienced by brooded embryos. In this study we separately investigated the impact of salinity stress (as low as 10) and hypoxia (1 ml O2 1 sub-1) experienced by brooded embryos of the deposit-feeding polychaete Capitella teleta on hatching success, metamorphosis, post-metamorphic survival, and post-metamorphic growth. Salinity reduction from 30 to 10 or 15 reduced relative hatching success, presumably by reducing embryonic survival, but generally had no negative latent effects on juvenile survival or growth. Prolonged exposure to hypoxic conditions had no negative effects, as seen on measurements recorded, other than abandonment of brood tubes by some females. There were no negative effects on days to emergence from brood tubes, numbers of larvae emerging from brood tubes, juvenile survival, or juvenile growth. Future studies should consider the potential role of maternal behavior in protecting embryos from at least short-term exposures to hypoxia, and the capacity for anaerobic metabolism in both embryos and adults of this species

Group-level differences in social network structure remain repeatable after accounting for environmental drivers

Individuals show consistent between-individual behavioural variation when they interact with conspecifics or heterospecifics. Such patterns might underlie emergent group-specific behavioural patterns and between-group behavioural differences. However, little is known about (i) how social and non-social drivers (external drivers) shape group-level social structures and (ii) whether animal groups show consistent between-group differences in social structure after accounting for external drivers. We used automated tracking to quantify daily social interactions and association networks in 12 colonies of zebra finches (Taeniopygia guttata). We quantified the effects of five external drivers (group size, group composition, ecological factors, physical environments and methodological differences) on daily interaction and association networks and tested whether colonies expressed consistent differences in day-to-day network structure after controlling for these drivers. Overall, we found that external drivers contribute significantly to network structure. However, even after accounting for the contribution of external drivers, there remained significant support for consistent between-group differences in both interaction (repeatability R: up to 0.493) and association (repeatability R : up to 0.736) network structures. Our study demonstrates how group-level differences in social behaviour can be partitioned into different drivers of variation, with consistent contributions from both social and non-social factors

El uso de parámetros magnéticos en estudios paleolimnológicos en Antártida

En esta contribución se describen las distintas técnicas y mediciones magnéticas utilizadas en Magnetismo Ambiental y Paleomagnetismo. Tales mediciones ofrecen útiles indicadores para realizar estudios relacionados con cambios climáticos y ambientales, así como herramientas de datación. Si bien es ampliamente conocida la utilidad de la susceptibilidad magnética, en primer lugar se discute el potencial y necesidad del uso de parámetros adicionales obtenidos a partir de mediciones de magnetizaciones remanentes (natural, anhistérica e isotérmica), histéresis magnética y estudios termomagnéticos. A continuación se presentan resultados magnéticos obtenidos en sedimentos lacustres del Archipiélago James Ross (NE de la Península Antártica) como un caso de estudio. Se complementa con estudios sedimentológicos, hidroquímicos, geoquímicos y de estadística multivariada, pero se pone énfasis en los parámetros magnéticos y su relación con los distintos procesos que ocurren en los sistemas lacustres antárticos. Se analiza además el uso de las paleointensidades relativas como herramienta de datación en lagunas antárticas

Children with grand Imaginaries: Bringing them closer to the world of science

Although at present there are academic strategies for scientific dissemination, it is still a challenge for the general population to access quality information that is reliable, easy to understand and motivational towards science. This article proposes an image-based educational scientific dissemination tool with the goal of bringing children closer to science, through the recognition of relevant characters and their contributions. The study was developed along three stages. The first and second were conducted through a qualitative analytical approach with an interpretative perspective, using a documental method, with a review and analysis technique. During the first stage, a review and selection of studies related to scientific dissemination for children was conducted. The second one focused on the identification and selection of scientific characters, through the establishment of categories and criteria. The third stage relates to the design of outstanding characters’ biographical cards. The main contribution of this proposal is the assembly of a semantic network to portray a completed character profile, time context, place of origin, contributions, impacts, acknowledgements or prizes, as well as limitations or difficulties in context. Therefore, a mean of disclosure was devised through cards with a highly graphic and animated content regarding scientific characters sized in a gaming strategy called ‘Sapiencia’, a ludic and motivational learning tool

Band structure engineering of chemically tunable LnSbTe (Ln = La, Ce, Pr)

The ZrSiS family of compounds has garnered interest as Dirac nodal-line semimetals and offers an approach to study structural motifs coupled with electronic features, such as Dirac crossings. CeSbTe, of the ZrSiS/PbFCl structure type, is of interest due to its magnetically tunable topological states. The crystal structure consists of rare earth capped square nets separating the magnetic Ce–Te layers. In this work, we report the single crystal growth, magnetic properties, and electronic structures of LnSb1−xBixTe (Ln = La, Ce, Pr; x ∼ 0.2) and CeBiTe, adopting the CeSbTe crystal structure, and the implication of tuning the electronic properties by chemical substitution