23 research outputs found
One-Dimensional Nanostructures and Devices of IIâV Group Semiconductors
The IIâV group semiconductors, with narrow band gaps, are important materials with many applications in infrared detectors, lasers, solar cells, ultrasonic multipliers, and Hall generators. Since the first report on trumpet-like Zn3P2nanowires, one-dimensional (1-D) nanostructures of IIâV group semiconductors have attracted great research attention recently because these special 1-D nanostructures may find applications in fabricating new electronic and optoelectronic nanoscale devices. This article covers the 1-D IIâV semiconducting nanostructures that have been synthesized till now, focusing on nanotubes, nanowires, nanobelts, and special nanostructures like heterostructured nanowires. Novel electronic and optoelectronic devices built on 1-D IIâV semiconducting nanostructures will also be discussed, which include metalâinsulator-semiconductor field-effect transistors, metal-semiconductor field-effect transistors, andpânheterojunction photodiode. We intent to provide the readers a brief account of these exciting research activities
Neonatal imitation predicts infant rhesus macaque (Macaca mulatta) social and anxiety-related behaviours at one year
The identification of early markers that predict the development of specific social trajectories is critical to understand the developmental and neurobiological underpinnings of healthy social development. We investigated, in infant rhesus macaques (Macaca mulatta), whether newbornsâ capacity to imitate facial gestures is a valid predictive marker for the emergence of social competencies later in development, at one year of age. Here we first assessed whether infant macaques (Nâ=â126) imitate lipsmacking gestures (a macaque affiliative expression) performed by a human experimenter in their first week of life. We then collected data on infantsâ social interactions (aggression, grooming, and play) and self-scratching (a proxy indicator of anxiety) at 11â14 months when infants were transferred into a new enclosure with a large social group. Our results show that neonatal imitators exhibit more dominant behaviours, are less anxious, and, for males only, spend more time in play at one year old. These findings suggest that neonatal imitation may be an early predictor of infant sociality and may help identify infants at risk of neurodevelopmental social deficits
Female philopatry and its social benefits among Bornean orangutans
Female philopatry in mammals is generally associated with ecological and sometimes social benefits, and often with dispersal by males. Previous studies on dispersal patterns of orangutans, largely non-gregarious Asian great apes, have yielded conflicting results. Based on 7 years of observational data and mitochondrial and nuclear DNA analyses on fecal samples of 41 adult Bornean orangutans (Pongo pygmaeus wurmbii) from the Tuanan population, we provide both genetic and behavioral evidence for male dispersal and female philopatry. Although maternally related adult female dyads showed similar home-range overlap as unrelated dyads, females spent much more time in association with known maternal relatives than with other females. While in association, offspring of maternally related females frequently engaged in social play, whereas mothers actively prevented this during encounters with unrelated mothers, suggesting that unrelated females may pose a threat to infants. Having trustworthy neighbors may therefore be a social benefit of philopatry that may be common among solitary mammals, thus reinforcing female philopatric tendencies in such species. The results also illustrate the diversity in dispersal patterns found within the great-ape lineage
Emotionality and intentionality in bonobo playful communication
Great apes show very complex systems for
communicating emotions and intentions. Whereas gestures
are intentional signals, facial expressions can disclose both
emotions and intentions. The playful context is a good field
to explore the possible dichotomy between intentionally
and emotionally driven signals as it has been suggested that
one of its functions is to learn producing and decoding
communicative patterns. To understand how signals are
produced during play and how they are modified in the
course of ontogeny, we investigated the use of playful
facial expressions and gestures in bonobos (Pan paniscus),
a tolerant species showing a high propensity to play even as
adults. Our results showed that the use of play faces and
gestures is strongly influenced by the characteristics of the
play session. Both play faces and gestures were more often
performed when social play involved physical contact and
when the receiver was visually attending, thus suggesting
that both signals can be strategically employed when
communicating becomes more urgent. Compared to play
faces, gestures were more frequent during dyadic than
polyadic sessions, when a unique receiver was involved.
Being gestures not context specific, they are probably used
more selectively by the sender. On the contrary, play faces
are context specific and transmit an unequivocal positive
message that cannot be misconceived. These features
legitimize a broad use of playful facial expressions, independently
of the number of playmates. The similarities and
differences in the production of these signals are probably
linked to the different degree of emotionality and intentionality
characterizing them