The food habits of the South Pacific hake (Merluccius gayi) from Ecuadorian waters were studied by analysing 232 stomachs of specimens ranging from 23.4–83.1 cm in total length (TL). Fish was the most important prey group (Alimentary Index, %AI = 94), Ctenosciaena peruviana being the most represented prey species (%AI = 62.17). PERMANOVA analysis showed dietary differences between the smallest individuals (class I < 30 cm TL) and the largest (class IV 40–45 cm TL; class V ≥ 45 cm TL). In addition, spatial differences in dietary composition were found between the three sampled regions (Manabí, Santa Elena and Guayas). The results of this study indicate that the South Pacific hake is an opportunistic predator feeding on a wide variety of vertebrate and invertebrate organisms.

En las sociedades andinas actuales las relaciones de parentesco determinan el tipo de matrimonio y el patrón de residencia posmarital que garantizan el manejo de los recursos, la supervivencia y la estabilidad reproductiva de la población. Sin embargo, es escasa la información disponible en el Área Andina Centro-Sur (AACS) para explicar los sistemas de parentesco durante el poblamiento original del territorio y su impacto en la estructura de las poblaciones locales posteriores a la conquista y colonización europea. En el presente trabajo se investiga el patrón residencial en dos sectores del AACS a partir de datos bioarqueológicos disponibles para el Noroeste Argentino y Norte de Chile. La información necesaria pudo ser recuperada a partir de la arqueología y de la antropología física regional. La muestra proviene de 8 localidades y 44 sitios con fechados que cubren el intervalo cronológico desde 3000 aC hasta 1450 dC, desde grupos arcaicos tempranos hasta comunidades agroalfareras tardías. Se emplearon 1.897 observaciones y 27 variables craneométricas. El análisis se realizó con técnicas estadísticas multivariadas: el cálculo de la varianza generalizada (determinante de la matriz de varianzas y covarianzas) para cada sexo y la estimación de los estadísticos de distancia (D2) y divergencia fenotípica (Fst) entre grupos y sexos. Los resultados revelan el efecto de distintos flujos migratorios que determinaron la estructura de las poblaciones. En todos los casos la varianza generalizada masculina es mayor que la femenina indicando una mayor variabilidad entre sitios y una mayor actividad migratoria. Los valores de D2 y Fst femeninos son mayores entre regiones y localidades con una menor tasa migratoria. Estos resultados indican, en general, la prevalencia de una estrategia de supervivencia basada en un sistema de parentesco que favoreció un modelo de residencia matrilocal.

Polymer-clay nanocomposites are compounds in which nanoclay particles are distributed in a polymer matrix. Epoxy-clay nanocomposites have become a very interesting topic among researchers in the past two decades because nanoclays have a positive effect on the mechanical, thermal and especially barrier anticorrosive performance of the polymers. In this study, epoxy-montmorillonite organoclay (OMMT) nanocomposite coatings were prepared and deposited on carbon steel substrates. The coatings were prepared through in situ polymerization and by UV-curing technique. The OMMT was added to epoxy resin at loadings between 0 wt.% and 5 wt.%, the particles of OMMT were dispersed using forced agitation-sonication and deposited on carbon steel coupons. The nanocomposite coatings obtained have been characterized by scanning electron microscopy (SEM), spectroscopy Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and evaluated their corrosion protection effect on cold rolled carbon steel coupons by performing visual analysis. The X-ray analysis showed that exfoliation occurred for the OMMT in the polymer matrix, the SEM analysis showed that OMMT was homogenous dispersed in the polymer matrix and the coatings were uniform. The FTIR analysis showed the characteristic bands of epoxy resin and OMMT in the composite. The results showed that 1 wt.% OMMT coating exhibit better anticorrosive properties than pure epoxy.

The diet and the feeding habits of the common dolphinfish (Coryphaena hippurus) in the Pacific coast of Ecuador was assessed by examining 320 stomachs of individuals ranging from 51 to 149 cm in total length. Fish was the predominant prey group in the diet (Alimentary Index, %AI = 95.39) followed by cephalopods (%AI = 4.13) and crustaceans (%AI = 0.48). Among the 17 prey items that make up the dolphinfish diet, the Exocoetidae family was the most important prey (%AI = 57.13), Dosidicus gigas being the most abundant invertebrate species (%AI = 7.65). Feeding patterns were evaluated using the graphing method of Amundsen, which suggested that this species shows a varying degree of specialization on different prey taxa. Thus, while some species were unimportant and rare (Hippocampus hippocampus, Lagocephalus lagocephalus, Gobiidae and Argonauta sp.), several dolphinfishes showed a high degree of specialization on Scombridae, Pleuroncodes planipes, Portunus xantusii and Opisthonema libertate. Size-related and temporal shifts in dietary composition were investigated by PERMANOVA analysis, which showed wide variations among size classes and periods of capture. The results of this study indicate that the common dolphinfish is an opportunistic feeder, which is capable of consuming a wide variety of schooling epipelagic organisms.

The diet of young Atlantic bluefin tuna (Thunnus thynnus) in the Bay of Biscay foraging ground was assessed using stomach-content analysis (SCA) and stable-isotope analysis coupled with isotope mixing model. Whereas SCA showed that the young tuna fed mainly on horse mackerel (Trachurus trachurus), the estimation of liver and muscle mixing model analyses indicated that northern krill (Meganyctiphanes norvegica) was the most important food resource. These contrasting observations are probably due to the different time scales spanned by the different methods. The present results suggest that young bluefin tuna prey at different trophic levels of the Bay of Biscay pelagic food web, thus behaving as an opportunist and generalist predator.

In the present work, we report the synthesis and characterization of NaNbO3 particles obtained by microwave-assisted hydrothermal method from Nb2O5 and NaOH. The synthesis was made at different periods at 180 °C and 300W. The crystallization of NaNbO3 structures produced Na2Nb2O6.H2O in the intermediate phase with fiber-like morphology, and this is associated with the synthesis time. Pure orthorhombic NaNbO3 with cube-like morphology originates after synthesizing for 240 minutes. To verify the remnant polarization of particles, films were obtained by electrophoresis process and sintered at 800°C for 10 minutes in a microwave furnace. The films characterization indicated that films of niobate with fiber-like morphology present remaining polarization, and the morphology of cubes did not show remaining polarization. Considering these results, it can be concluded that the morphology implemented ferroelectric property of NaNbO3.

Quantitative analysis of macroecological patterns for late Pleistocene assemblages can be useful for disentangling the causes of late Quaternary extinctions (LQE). However, previous analyses have usually assumed linear relationships between macroecological traits, such as body size and range size/range shift, that may have led to erroneous interpretations. Here, we analyzed mammalian datasets to show how macroecological patterns support climate change as an important driver of the LQE, which is contrary to previous analyses that did not account for more complex relationships among traits. We employed quantile regression methods that allow a detailed and fine-tuned quantitative analysis of complex macroecological patterns revealed as polygonal relationships (i.e., constraint envelopes). We showed that these triangular-shaped envelopes that describe the macroecological relationship between body size and geographical range shift reflect nonrandom extinction processes under which the large-bodied species are more prone to extinction during events of severe habitat loss, such as glacial/interglacial transitions. Hence, we provide both a theoretical background and methodological framework to better understand how climate change induces body size-biased species sorting and shapes complex macroecological patterns.

A number of systems based on synthetic molecules, among them cationic liposomes and poly(ethylene imine)-based polymers, have been proposed as delivery vehicles for nucleic acids. Some of these systems have even reached the market, ensuring efficient and transient transfection levels in a variety of cell types. However, toxicity issues have limited their application in vivo. In this context, chitosan, a biocompatible and biodegradable polysaccharide, has been proposed as a promising alternative for the delivery of nucleic acid-based molecules. Here we present an overview of the state of the art of chitosan-based vectors for nucleic acid delivery and the most recent data on the in vivo testing of the proposed systems. We additionally express our view on the barriers that might be hampering the translation of this knowledge into clinical practice and the challenges that need to be fulfilled for these promising vehicles to reach patients.

This research shows the influence of the synthesis route in the structural and morphological characteristics as well as in the luminescent properties of doped with europium and pure SrTiO3 (STO) powders prepared by microwave assisted hydrothermal synthesis, MWH, and by the polymeric precursor method, PPM. The XRD at room temperature of the STO powders nominally pure obtained by PPM at 700°C for 3 hours, as well as by the MWH at 190°C by 30 minutes present all the reflection peaks for the cubic perovskite structure (JCPDS-ICDD 35-734). The morphology varies according to the synthesis route. The particles of pure STO obtained by PPM presents morphology in the form of plates and the morphology of the particles synthesized by MWH is spherical with approximately 150 nm. The photoluminescent analysis shows for pure STO wide bands associated with the transition of charge transfer from the titanates group (TiO3)2- that are centered on 450 nm. In both preparation methods the emission bands obtained in the composites spectra were found to be asymmetric and low intense. However, in the case of the STO prepared by the PPM a bigger FWHM of the band can be observed. The excitation of the samples was done using a laser (Coherent Innova) with wavelength of 350 nm.

Scanning probe microscopy (SPM) was used to probe piezoelectric vibrations and local conductivity in CaCu3Ti4O12(CCTO) ceramics at room temperature. Piezoelectric contrast was observed on the polished surfaces of CCTO in both vertical (out-of-plane) and lateral (in-plane) modes and depended on the grain orientation varying in sign and amplitude. The piezoelectric contrast is shown to be controlled by the electrical bias (local poling) and displayed a ferroelectric-like reversible hysteresis accompanied with a change of the phase of piezoelectric signal. Flexoelectric effect (strain-gradient-induced polarization) due to surface relaxation was invoked to explain the observed contrast inside the grains.

Se estudia la diferenciación temporal y la divergencia genética entre los períodos Formativo (300 a.C–400 d.C), Tiwanaku (400 d.C–1000 d.C.) y Desarrollo Regional (1000 d.C–1470 d.C.) del grupo inhumado en el ayllu de Quitor de San Pedro de Atacama (Norte de Chile), con el fin de conocer si existen cambios biológicos asociados con los períodos o fases del desarrollo cultural de la región. La muestra está representada por 326 individuos provenientes de diferentes sitios o sectores del yacimiento. Para evaluar las diferencias fenotípicas entre períodos se emplearon 37 caracteres métricos del cráneo y un conjunto de procedimientos de análisis estadístico uni y multivariado. En el marco de la teoría genética de los caracteres cuantitativos se espera que el parentesco de cada período junto con la varianza fenotípica, fluctúen de acuerdo con el tamaño efectivo y el aporte migratorio desde regiones próximas y más o menos distantes. En efecto, el parentesco promedio estimado para este ayllu (FST) fue de .03, siendo mayor en mujeres que en hombres. En general, de acuerdo con este valor es posible inferir que los habitantes de Quitor vivieron en una condición de mayor aislamiento que los grupos agroalfareros asentados en el Valle de Azapa (FST = .013). Además en el período Medio (Tiwanaku) se produjo un incremento moderado de la varianza fenotípica producida probablemente por un exceso de flujo gènico proveniente de regiones próximas.

Estudios anteriores basados en indicadores osteológicos comprobaron la existencia de un alto impacto ambiental afectando el crecimiento y desarrollo normal de los habitantes de Las Pirguas (Salta), un grupo del período agroalfarero del noroeste argentino (aproximadamente 600 d.C.), por la acción de factores nutricionales y socioculturales. Puesto que tales condiciones de vida tienen que haber comprometido además la estabilidad del desarrollo de los individuos, es apropiada su evaluación mediante el análisis de la repetibilidad (r) de mediciones bilaterales del cráneo y de su complemento (1 - r) la varianza ambiental especial. Se empleó una muestra de 60 individuos y la observación de 21 variables bilaterales del cráneo, habiéndose controlado el error intraobservador. Los resultados indican la existencia de diferencias bilaterales significativas a favor del lado derecho en las dimensiones: NA-FMO, PT-FMT, BRE-AS y PO-BRE, mientras que las restantes variables presentan promedios semejantes. Los individuos adultos poseen una repetibilidad media (.744 ± .025), menor en un 19.3 por ciento a la de los infantiles (.922 ± .013), y comparativamente más baja con respecto a otras poblaciones del Área Andina Centro Meridional. Estos resultados confirman el perfil de vida marginal y de extremas exigencias ambientales bajo las cuales vivió esta población.

The effect of calcination temperature during the formation of the solid solution Sn0.9Ti0.1O2 doped with 1.00 mol % CoO and 0.05 mol % Nb2O5 is presented. The structural characteristics of this system were studied using X-ray diffraction, and the changes in phase formation were analyzed using the Rietveld method. With an increase in calcination temperature, there is increasing miscibility of Ti into the (Ti,Sn)O2 phase and near 1000 °C, and the remaining TiO2 (anatase) was transformed into the rutile phase. The sintering process, monitored using dilatometry, suggests two mass transport mechanisms, one activated close to 900 °C associated with the presence of TiO2 (anatase) and the second mechanism, occurring between 1200 and 1300 °C, is attributed to a faster grain boundary diffusion caused by oxygen vacancies.

BaTiO3 powders were prepared through mechanical activation chemistry and analyzed by Rietveld refinement with X-ray diffraction data. Raw BaCO3 and TiO2 powders were dry milled for 5 and 20 h and then calcinated for 2 and 4 h at 800 °C. The milling process was found to have broken up the BaCO3 and TiO2 crystals into smaller crystals and formed only small amounts (<1.5 wt%) of BaTiO3. Subsequence calcinations for 2 and 4 h at 800 °C successfully produced large amounts (>97.7 wt%) of BaTiO3 crystals. The calcination process also generated microstrains and crystallite-size anisotropy in BaTiO3. An increase in the calcination time from 2 to 4 h increased the BaTiO3 weight percentage and the crystallite-shape anisotropy, but decreased the tetragonal distortion anisotropic microstrains in BaTiO3 crystals.