Estimación de la emigración del camarón café Farfantepenaeus aztecus a través de la boca del Mezquital, Tamaulipas, México

Se presentan la variación en abundancia de juveniles de camarón café (Farfantepeneaeus aztecus) durante su principal periodo de emigración hacia el mar, en la boca del Mezquital, Tamaulipas. Los muestreos fueron realizados entre mayo y julio del 2003 al 2007 y consistieron en el uso de una red de corriente experimental durante el periodo nocturno y durante periodos de bajamar, en los tres días anteriores y posteriores a la presencia de luna nueva y llena. La información fue complementada con datos de abundancia obtenidos con arrastres en cruceros de investigación realizados en la costa de Tamaulipas durante mayo a julio del 2003 al 2007. Los resultados muestran que los máximos valores de emigración (kg/noche) se presentan durante el periodo lunar a finales de mayo y/o principios de junio, indistintamente de la fase lunar y se relacionaron directamente con aumentos en los valores de abundancia en la zona costera y marina. Estos resultados son de gran importancia porque demuestran que mayo y junio son meses críticos para esta especie, y sirven como base para la definición de los periodos de veda para la pesca de camarón, tanto en la zona lagunar como en altamar

Effect of Sorbitol Templates on the Preferential Crystallographic Growth of Isotactic Polypropylene Wax

The crystallization of isotactic polypropylene wax (iPP) in the presence of different sorbitol structures was studied. Dibenzylidene Sorbitol (DBS), as well as two of its derivatives with one or two methyl groups in the DBS molecule (MDBS and DMDBS, respectively), were tested as nanometer-size fibrillar templates. The early nucleation stage and crystal morphology were analyzed in Real-Time Wide-Angle X-ray Scattering (WAXS) and polarized optical microscopy (POM). It was found that the iPP crystals showed an α-phase unit cell for the three different sorbitols. However, a preferential crystal growth in the plane (040) was observed for iPP–MDBS. The macrostructure morphology of the iPP–DBS and iPP–DMDBS wax compounds was spherulitic, while nodular macrocrystals were observed for the iPP–MDBS compound. It was concluded that the MDBS template promoted a lower interface energy because of its match with the c-axis of the iPP wax crystals, whereas, in the case of the DBS and DMDBS templates, the preferential plane was the (110), characteristic of the iPP spherulitic arrangement

Top predator ecology and conservation: Lesson from jaguars in southeastern Mexico

Our research is the most comprehensive study of jaguar behavior ecology in Mexico. By analyzing and describing the movements and use of the space, as well as the interactions among individual jaguars, we can better understand their behavioral differences, habitat use, and home range. This type of information is critical for the development and implementation of effective and appropriate conservation strategies. We identified home range size for 14 jaguars in a 13‐year period and described the interspecific relations and use of space by the percentages of overlap of the territories between individuals. Collectively, the average home range size was larger than 200 km2, ranging from 48 to 633 km2 and averaging 296 km2 for males varied and 37–435 km2, with an average of 148 km2, for females. However, home range sizes did not differ significantly among males or females. Male territory overlapped about 3.3% on average (range 2.5–15.5%), suggesting that most of the time males avoid each other. Average overlap of female territory was 12%, ranging from 7 to 100%. Males share an average of 18% (range 2–56%) of its territory and with up to five females, suggesting that a given male may be related to all of them at certain periods of time. There were no seasonal changes (dry and rainy seasons) in home range sizes for both male and females. Our research is an important contribution to the ecological information essential for landscape‐level conservation plans for the protection of the jaguars and the biological diversity of the wider Yucatan Peninsula in which they inhabit. Our research is the most comprehensive study of jaguar behavior ecology in Mexico. By analyzing and describing the movements and use of the space, as well as the interactions among individual jaguars, we can better understand their behavioral differences, habitat use, and home range. This type of information is critical for the development and implementation of effective and appropriate conservation strategies. We identified home range size for 14 jaguars in a 13‐year period and described the interspecific relations and use of space by the percentages of overlap of the territories between individuals. Collectively, the average home range size was larger than 200 km2, ranging from 48 to 633 km2 and averaging 296 km2 for males varied and 37–435 km2, with an average of 148 km2, for females. However, home range sizes did not differ significantly among males or females. Male territory overlapped about 3.3% on average (range 2.5–15.5%), suggesting that most of the time males avoid each other. Average overlap of female territory was 12%, ranging from 7 to 100%. Males share an average of 18% (range 2–56%) of its territory and with up to five females, suggesting that a given male may be related to all of them at certain periods of time. There were no seasonal changes (dry and rainy seasons) in home range sizes for both male and females. Our research is an important contribution to the ecological information essential for landscape‐level conservation plans for the protection of the jaguars and the biological diversity of the wider Yucatan Peninsula in which they inhabit.The authors would like to thank the Alianza WWF – Fundacion Telmex/Telcel, the Universidad Nacional Autonoma de Mexico (project DGAPA, PAPIT IN208017), Amigos de Calakmul A.C., and the BBVA Foundation Award for the Conservation of Biodiversity (2017) for funding and support for this project

Effect of filler functionalization on thermo-mechanical properties of polyamide-12/carbon nanofibers composites: a study of filler-matrix molecular interactions

The effect of carbon nanofiber (CNF) functionalization on the thermo-mechanical properties of polyamide-12/CNF nanocomposites was investigated. Three main different surface treatments were performed to obtain CNF-OH (OH rich), CNF-Silane (C6H5Si-O-), and CNF-peroxide. CNF modified with poly-(tert-butyl acrylate) chains grown from the surface via ATRP (atom transfer radical polymerization) were also prepared and tested. The modified CNFs and neat CNFs were used as fillers in polyamide-12 nanocomposites and the properties of the ensuing materials were characterized and compared. Universal tensile tests demonstrated a substantial increase (up to 20 %) of the yield strength, without reduction of the final elongation, for all functionalized samples tested within 1 wt% filler content. Further evidences of mechanical properties improvement were given by dynamic mechanical thermal analyses. CNFs functionalized with poly-(tert-butyl acrylate) and silane exhibited the best performance with stiffening and strengthening at low (a parts per thousand currency sign1 wt%) filler loadings, via a partial decrease of the intensity of beta-transitions attributed to favorable interactions between the functional groups on the surface of functionalized CNFs and polyamide-12. CNFs treated with peroxide proved to be the most simple preparation technique and the ensuing nanocomposites exhibited the highest storage modulus at high (5 wt%) filler content. Theoretical simulations using the micro-mechanics model were used to predict the Young modulus of the composites and compare them with experimental data. The results obtained suggest a synergistic effect between the matrix and the filler enhanced by surface functionalization

Deforestation Impacts on Bat Functional Diversity in Tropical Landscapes

<div><p>Functional diversity is the variability in the functional roles carried out by species within ecosystems. Changes in the environment can affect this component of biodiversity and can, in turn, affect different processes, including some ecosystem services. This study aimed to determine the effect of forest loss on species richness, abundance and functional diversity of Neotropical bats. To this end, we identified six landscapes with increasing loss of forest cover in the Huasteca region of the state of Hidalgo, Mexico. We captured bats in each landscape using mist nets, and calculated functional diversity indices (functional richness and functional evenness) along with species richness and abundance. We analyzed these measures in terms of percent forest cover. We captured 906 bats (Phyllostomidae and Mormoopidae), including 10 genera and 12 species. Species richness, abundance and functional richness per night are positively related with forest cover. Generalized linear models show that species richness, abundance and functional richness per night are significantly related with forest cover, while seasonality had an effect on abundance and functional richness. Neither forest cover nor season had a significant effect on functional evenness. All these findings were consistent across three spatial scales (1, 3 and 5 km radius around sampling sites). The decrease in species, abundance and functional richness of bats with forest loss may have implications for the ecological processes they carry out such as seed dispersal, pollination and insect predation, among others.</p></div