Diferencias anatómicas, fisiológicas y químicas entre poblaciones de Pseudocyphellaria flavicans (Hook. f. & Taylor) Vain. de Chile

Environmental conditions can affect lichen morphology, physiology and chemistry. Some functional traits; like thickness of thalluslayers, photosystems condition, and presence of photoprotective and antioxidant compounds are key to colonizing new sites, and canchange depending on light and moisture availability. In the present study, we compared the morphology, physiology and chemistry ofthe native Chilean lichen Pseudocyphellaria flavicans from two Coastal populations (Nahuelbuta and Contulmo, Araucanía district),and one Andean population (Ralco, Bío-Bío district). Ralco is a more closed secondary forest, and can show dryer periods comparedto Nahuelbuta and Contulmo. We found differences in thalli anatomy between populations. Ralco individuals had thinner uppercortex than Nahuelbuta individuals. Contulmo individuals had similar upper cortex thickness compared to the other two populations.We also found differences in the response of the maximal efficiency of the PSII (Fv/Fm) to desiccation and in the in situ valuesmeasured. We did not find differences between populations in the chemical traits. The differences between populations could beattributed to differences in local environmental conditions, namely moisture and light.Las condiciones ambientales afectan la morfología, fisiología y química de los líquenes. Ciertos rasgos funcionales, como el grosorde las distintas capas del talo, estado de los fotosistemas, y presencia de compuestos fotoprotectores y antioxidantes son claves paracolonizar nuevos sitios y pueden variar dependiendo de la disponibilidad de luz y humedad. En este trabajo se comparó la morfología,fisiología y química de individuos del liquen nativo de Chile Pseudocyphellaria flavicans de dos poblaciones de la Cordillera de laCosta (Nahuelbuta y Contulmo, Región de la Araucanía) y una de la Cordillera de los Andes (Ralco, Región del Bío-Bío). Ralco es unbosque más cerrado y presenta periodos más secos, comparado con Nahuelbuta y Contulmo. Se encontraron diferencias significativasen la anatomía del talo entre poblaciones. Los individuos de Ralco presentaron una corteza superior más delgada en relación con losde Nahuelbuta. Los individuos de Contulmo presentaron una corteza similar a las otras dos poblaciones. También se encontrarondiferencias en las curvas de respuesta de la eficiencia máxima del PSII (Fv/Fm) a la desecación y los valores medidos in situ. No seencontraron diferencias entre poblaciones en las variables químicas medidas. Las diferencias entre poblaciones podrían atribuirse adiferencias en las condiciones ambientales locales, principalmente humedad y luminosidad

Homogenized out-of-plane shear response three-scale fiber-reinforced composites

In the present work we embrace a three scales asymptotic homogenization approach to investigate the effective behavior of hierarchical linear elastic composites reinforced by cylindrical, uniaxially aligned fibers and possessing a periodic structure at each hierarchical level of organization. We present our novel results assuming isotropy of the constituents and focusing on the effective out-of-plane shear modulus, which is computed exploiting the solution of the arising anti-plane problems. The latter are solved semi-analytically by means of complex variables and successfully benchmarked against the results obtained by finite elements. Our findings can pave the way for multiscale modeling of complex hierarchical materials (such as bone and tendons) at a negligible computational cost

SAFA and GeoGebra Allies to Evaluate Natural and Cultural Sustainability: Yasuni Biosphere Reserve

The Yasuni Biosphere Reserve (YBR) occupies a unique biogeographic position in the world, where the richness of the four taxa (amphibians, birds, mammals and vascular plants) reaches maximum diversity. However, threats to species conservation are latent: the opening of roads, illegal logging, the advance of the agricultural frontier, oil extraction and the trade of wild meat in the western sector of the reserve. This paper aims to evaluate the sustainability of natural resources in multicultural communities: 1) Waorani Indigenous and 2) Migrant settlers, settled in the Diversity and Life Strip (DLS) in the YBR. Three households were defined per community, selected from the snowball sampling method. Thus, three methodological processes were applied: 1) Sustainability of natural resources using the SAFA program (version 2.4.1), it has four dimensions Good Governance (GG), Environmental Integrity (EI), Economic Resilience (ER) and Social Welfare (SW); 2) Direct observation; and 3) Lacing algorithm with the GeoGebra program used for the calculation of areas of simple polygons. The results showed that the dimension of least sustainability was ER in indigenous households and in-migrant settler households it was ER and SW. The largest sustainability area of 25,12 u2 in the migrant settler household1, while in Waorani indigenous the worst sustainability area had a value of 18,69 u2. The programs allow to promote a better understanding of the dynamics of the sustainability of natural resources. The issues identified as limited in the communities are a priority to improve sustainability.

Three scales asymptotic homogenization and its application to layered hierarchical hard tissues

In the present work a novel multiple scales asymptotic homogenization approach is proposed to study the effective properties of hierarchical composites with periodic structure at different length scales. The method is exemplified by solving a linear elastic problem for a composite material with layered hierarchical structure. We recover classical results of two-scale and reiterated homogenization as particular cases of our formulation. The analytical effective coefficients for two phase layered composites with two structural levels of hierarchy are also derived. The method is finally applied to investigate the effective mechanical properties of a single osteon, revealing its practical applicability in the context of biomechanical and engineering applications

The influence of anisotropic growth and geometry on the stress of solid tumors

Solid stresses can affect tumor patho-physiology in at least two ways: directly, by compressing cancer and stromal cells, and indirectly, by deforming blood and lymphatic vessels. In this work, we model the tumor mass as a growing hyperelastic material. We enforce a multiplicative decomposition of the deformation gradient to study the role of anisotropic tumor growth on the evolution and spatial distribution of stresses. Specifically, we exploit radial symmetry and analyze the response of circumferential and radial stresses to (a) degree of anisotropy, (b) geometry of the tumor mass (cylindrical versus spherical shape), and (c) different tumor types (in terms of mechanical properties). According to our results, both radial and circumferential stresses are compressive in the tumor inner regions, whereas circumferential stresses are tensile at the periphery. Furthermore, we show that the growth rate is inversely correlated with the stresses’ magnitudes. These qualitative trends are consistent with experimental results. Our findings therefore elucidate the role of anisotropic growth on the tumor stress state. The potential of stress-alleviation strategies working together with anticancer therapies can result in better treatments

The role of malignant tissue on the thermal distribution of cancerous breast

The present work focuses on the integration of analytical and numerical strategies to investigate the thermal distribution of cancerous breasts. Coupled stationary bioheat transfer equations are considered for the glandular and heterogeneous tumor regions, which are characterized by different thermophysical properties. The cross-section of the cancerous breast is identified by a homogeneous glandular tissue that surrounds the heterogeneous tumor tissue, which is assumed to be a two-phase periodic composite with non-overlapping circular inclusions and a square lattice distribution, wherein the constituents exhibit isotropic thermal conductivity behavior. Asymptotic periodic homogenization method is used to find the effective properties in the heterogeneous region. The tissue effective thermal conductivities are computed analytically and then used in the homogenized model, which is solved numerically. Results are compared with appropriate experimental data reported in the literature. In particular, the tissue scale temperature profile agrees with experimental observations. Moreover, as a novelty result we find that the tumor volume fraction in the heterogeneous zone influences the breast surface temperature

Erythrolamprus dorsocorallinus (Esqueda, Natera, La Marca & Ilija-Fistar, 2005) (Squamata: Dipsadidae): range extension, new country record, and comments on color pattern

We present a new country record and significant range extension of Erythrolamprus dorsocorallinus from Bolivia. Locality data on this species is lacking and this account significantly contributes to the knowledge its distributional status throughout South America.

Effective properties of periodic fibrous electro-elastic composites with mechanic imperfect contact condition

International audienceIn this work, two-phase parallel fiber-reinforced periodic piezoelectric composites are considered wherein the constituents exhibit transverse isotropy and the cells have different configurations. Mechanical imperfect contact at the interface of the composites is studied via linear spring model. The statement of the problem for two phase piezoelectric composites with mechanical imperfect contact is given. The local problems are formulated by means of the asymptotic homogenization method (AHM) and their solutions are found using complex variable theory. Analytical formulae are obtained for the effective properties of the composites with spring imperfect type of contact and different parallelogram cells. Some numerical examples and comparisons with other theoretical results illustrate that the model is efficient for the analysis of composites with presence of parallelogram cells and the aforementioned imperfect contact

The TICs and their incidence to develop didactic resources within teaching planning

Using ICT in teaching practice, it helps to contribute knowledge through digital tools that meet the visible needs of students. These have immersed in a constant technological evolution in which they are recognized as digital natives, ICTs have an impact on the development of digital teaching resources, due to the different gamification platforms that are developed in the network, and these means allow planning innovations teachers and generate meaningful learning through recreational activities. This research work shows the influence of TICs, in the teaching-learning process as a significant and important element in the educational field. However there are teachers who do not know these methods of illustration, which have traditionalist practices included In the curricular planning that do not contribute to the proposed objectives, there are also teachers with extensive knowledge in this area, who should demonstrate the benefit of using Web 3.0. In the consolidation of knowledge and contribute through training aimed at the teaching staff to socialize this new methodology

Fortalecimiento de valores ambientales a través de estrategias lúdicas en los estudiantes del grado sexto de la institución educativa Luis Carlos Galán Sarmiento de Acacías –Meta

En el presente trabajo se aborda la importancia de fortalecer valores ambientales para fomentar una cultura que priorice la necesidad de tomar acciones favorables para el cuidado y conservación de nuestros recursos naturales. Para tal fin, se toma la lúdica como estrategia pedagógica, partiendo de la premisa de que como dimensión del ser humano, permite sensibilizar al estudiante y comunidad educativa en general acerca de su responsabilidad con el cuidado de la naturaleza