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Parental care directly affects the fitness of individuals because it increases the probability of offspring survival. Therefore, it is expected that parents be particularly motivated to return (i.e., exhibit homing behavior) and resume care if they are moved away from offspring by disturbances. Yet, despite several studies on the behavioral ecology of homing in vertebrates, aspects underlying the relationship between movement and offspring care in anurans remain largely unknown. We tested the relative importance of parental care as a driver of homing in Ikakogi tayrona, the only glassfrog with demonstrated prolonged maternal care. We carried out translocation experiments in 58 calling males, 23 gravid females, and 19 females caring for eggs. Contrary to expectations, females did not exhibit homing despite the risk of increased offspring mortality. On the other hand, males exhibit homing (they returned from translocation distances up to 320 m), possibly to recover a specific territory that is important for attracting mates. Taken together, our work documents a paradoxical result that may lead to future research testing specific hypothesis about the causes of sex differences in homing and the associated cognitive process. Significance statement: Studying the relationship between parental care and homing behavior provides a better understanding of how diverse ecological and evolutionary factors influence movement patterns in animals. However, such relationship has been almost untested in anurans, even though their homing behavior and diversity of parental care strategies have separately received great attention from behavioral ecologists. In this study, we found sex differences in homing for the glassfrog Ikakogi tayrona. Males are highly motivated to return to a specific territory, possibly to recover a particular place from which they increase mating opportunities. Interestingly, females caring for eggs did not exhibit homing, even if that behavioral decision results in higher mortality rates of offspring in their clutches, as demonstrated in this and other glassfrogs. This work is one of the few studies on homing in anurans that includes a large sample size of females and accounts for both gravid females and females already caring for offspring. Altogether, this study broadens our understanding of how ecological and evolutionary factors can influence homing behavior in vertebrates. [ABSTRACT FROM AUTHOR]

In the last decade, numerous investigations have been devoted to the preparation of polypropylene-multiwalled carbon nanotubes (PP/MWCNT) nanocomposites having enhanced properties, and in particular, high electrical conductivities (> 1 S cm−1). The present work establishes that the highest electrical conductivity in PP/MWCNT nanocomposites is limited by the amount of nanofiller content which can be incorporated in the polymer matrix, namely, about 20 wt%. This concentration of MWCNT in PP leads to a maximum electrical conductivity slightly lower than 8 S cm−1, but only by assuring an adequate combination of dispersion and spatial distribution of the carbon nanotubes. The realization of such an optimal microstructure depends on the characteristics of the production process of the PP/MWCNT nanocomposites; in our experiments, involving composite fabrication by melt mixing and hot pressing, a second re-processing cycle is shown to increase the electrical conductivity values by up to two orders of magnitude, depending on the MWCNT content of the nanocomposite. A modest increase of the highest electrical conductivity obtained in nanocomposites with 21.5 wt% MWCNT content has been produced by the combined use of carbon nanofibers (CNF) and MWCNT, so that the total nanofiller content was increased to 30 wt% in the nanocomposite with PP—15 wt% MWCNT—15 wt%CNF. [ABSTRACT FROM AUTHOR]

This study investigated the association between two creativity indicators: Divergent Thinking (DT) and Creative Personality (CP), and key aspects of cognitive ability, personality (Big Five), and trait emotional intelligence (trait EI or trait emotional self-efficacy). The sample consisted of 175 Spanish undergraduates and recent graduates from three university subject domains: Technical & Natural Sciences, Social Sciences, and Arts. Cognitive ability was found to bear little relationship to either index of creativity. In contrast, strong relationships were demonstrated between personality traits, including trait EI, and creativity, some of which varied significantly across subject domains. Results suggest that future research will have to pay particular attention to individual differences in the affective parts of the personality realm that are comprehensively captured by the construct of trait EI. [ABSTRACT FROM AUTHOR]

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Flow experiments through capillaries with 0.2% xanthan in aqueous solution and 0.1 N NaCl brine were carried out to study the influence of the molecular conformation on the flow development at relatively low shear rates, from 20s to 400s. Capillaries with a wide range of length-to-diameter ratios, L/D = 4.5 to 1015 were used. The apparent viscosity as a function of L/D at a constant shear rate shows a continuous decrement of the viscosity as L/D increases, until an asymptotic value is reached. The decrement in the apparent viscosity is partially explained in terms of slip. It was found that slip is a function of L/D as well as shear stress, i.e., slip develops during flow, thus inducing spatial anisotropy in the fluid until a stable state is reached. However, the substantial difference in apparent viscosity between short capillaries and capillaries longer than 300 D may be attributed to dominant elongational flow due to the contraction in the small capillaries and slip in long capillaries. The flow in a sufficiently long capillary can be divided in four regions rather than three, as is usually assumed. In the first region, which corresponds to the entry, elongational and shear flow coexist and elongational flow dominant. In the second region, end effects and slip development are coupled. In the third region the flow is fully developed and end effects are negligible. However, the fluid shows physical characteristics different from those of the fluid at rest, as a consequence of prior slip development. The fourth zone is the exit region in which the velocity rearranges due to the change of boundary conditions. The length of each region depends on the conformation of the macromolecules and shear rate. In addition, it was found that the stiffness of xanthan increases with the increase of the ionic strength. Finally, a performance of Bagley's analysis in the whole range of L/D studied showed that the use of the Bagley correction is not a reliable way to correct for end effects when the flow is not fully developed and/or in the presence of slip. [ABSTRACT FROM AUTHOR]

Using recombinant DNA techniques, an Aspergillus nidulans multicopy transformant for the gene xlnB coding for the minor X xylanase has been constructed. When grown on glucose as sole carbon source this transformant secretes 114 U of xylanase (mg protein). In this culture condition, X is the only xylanase secreted and the predominant protein in the culture filtrate. This strategy has been used to purify the X enzyme to homogeneity. The purified xylanase showed a single band on sodium dodecyl sulphate/ polyacrylamide gel electrophoresis with a molecular mass of 24 kDa and had an isoelectric point of approximately 3.5. The enzyme was a non-debranching endo-1,4-β-xylan xylanohydrolase highly specific for xylans and showed optimal activity at pH 5.5 and 52°C. The X xylanase had a Michaelis constant, K, of 12.43 mg oat spelt xylan ml and a V of 1639 μmol min (mg protein). [ABSTRACT FROM AUTHOR]

Two polypeptides showing α- l-arabinofuranosidase activity have been purified to homogeneity from culture supernatants of a Bacillus subtilis clone harbouring the xynD gene [Gosalbes et al. (1991) J Bacteriol 173: 7705-7710] from Bacillus polymyxa. Both polypeptides, with determined molecular masses of 64 kDa and 53 kDa, share the same sequence at their N termini, which also coincides with the sequence deduced for the mature protein from the previously determined sequence of nucleotides (Gosalbes et al. 1991). The two polypeptides have been biochemically characterized. Arabinose is the unique product released from arabinose-containing xylans which are substrates for both enzyme forms. Other natural arabinose-containing polysaccharides, such as arabinogalactans, are not attacked by them but some artificial arabinose derivatives are good substrates for both polypeptides. Their arabinose-releasing activity on arabinoxylans facilitates the hydrolysis of the xylan backbone by some endoxylanases from Bacillus polymyxa. [ABSTRACT FROM AUTHOR]

An efficient transformation system for the fungus Trichoderma longibrachiatum has been developed. Transformation was obtained both by electroporation and polyethyleneglycol treatment, using a plasmid carrying the Escherichia coli hygromycin B phosphotransferase gene as a dominant selectable marker. The transformation frequency was 0.5 to 5 transformants /μg plasmid DNA. Transformation normally occurred by tandem integration of the transforming DNA. A high percentage of the transformants were mitotically unstable. The efficiency of co-transformation was very high (around 90%), and several co-transformants containing multiple copies of the egll gene encoding a β-(1,4)-endoglucanase were obtained. Some of them secrete increased levels of endoglucanase to the culture medium. In addition, the E. coli lacZ gene was expressed in an active form under control of the Aspergillus nidulans gpdA gene promoter. [ABSTRACT FROM AUTHOR]

A gene ( egl1) encoding an endoglucanase (EGL1) from Trichoderma longibrachiatum has been cloned and sequenced. This gene, homologous to the T. reesei egl1 gene, differs from it in the length of the introns (particularly the first one) and encoded protein. A cDNA fragment obtained by the rapid amplification of cDNA ends method, which takes advantage of the polymerase chain reaction, has been expressed in yeast under control of the cyc-gal inducible promoter and yeast clones able to secrete active enzyme have been obtained. [ABSTRACT FROM AUTHOR]