What drives young children to over-imitate? Investigating the effects of age, context, action type, and transitivity

Imitation underlies many traits thought to characterize our species, which includes the transmission and acquisition of language, material culture, norms, rituals, and conventions. From early childhood, humans show an intriguing willingness to imitate behaviors, even those that have no obvious function. This phenomenon, known as “over-imitation,” is thought to explain some of the key differences between human cultures as compared with those of nonhuman animals. Here, we used a single integrative paradigm to simultaneously investigate several key factors proposed to shape children’s over-imitation: age, context, transitivity, and action type. We compared typically developing children aged 4–6 years in a task involving actions verbally framed as being instrumental, normative, or communicative in function. Within these contexts, we explored whether children were more likely to over-imitate transitive versus intransitive actions and manual versus body part actions. Results showed an interaction between age and context; as children got older, they were more likely to imitate within a normative context, whereas younger children were more likely to imitate in instrumental contexts. Younger children were more likely to imitate transitive actions (actions on objects) than intransitive actions compared with older children. Our results show that children are highly sensitive to even minimal cues to perceived context and flexibly adapt their imitation accordingly. As they get older, children’s imitation appears to become less object bound, less focused on instrumental outcomes, and more sensitive to normative cues. This shift is consistent with the proposal that over-imitation becomes increasingly social in its function as children move through childhood and beyond

Morphology of Three Imported Aphthona Flea Beetles Used as Biological Control Agents of Leafy Spurge

The following morphological study of the three imported Aphtona flea beetles supplies a detailed description of selected structures that will distinguish each of the three imported species and will separate them from a common native fle beetle (Glyptina atriventris) found at South Dakota release sites

Signal generation and mixing electronics for frequency-domain lifetime and spectral fluorometry

The present invention additionally comprises a method and apparatus for generating and mixing signals for frequency-domain lifetime and spectral fluorometry. The present invention comprises a plurality of signal generators that generate a plurality of signals where the signal generators modulate the amplitude and/or the frequency of the signals. The present invention uses one of these signals to drive an excitation signal that the present invention then directs and transmits at a target mixture, which absorbs the energy from the excitation signal. The property of fluorescence causes the target mixture to emit an emitted signal that the present invention detects with a signal detector. The present invention uses a plurality of mixers to produce a processor reference signal and a data signal. The present invention then uses a processor to compare the processor reference signal with the data signal by analyzing the differences in the phase and the differences in the amplitude between the two signals. The processor then extracts the fluorescence lifetime and fluorescence spectrum of the emitted signal from the phase and amplitude information using a chemometric analysis

Chemoenzymatic elaboration of monosaccharides using engineered cytochrome P450_(BM3) demethylases

Polysaccharides comprise an extremely important class of biopolymers that play critical roles in a wide range of biological processes, but the synthesis of these compounds is challenging because of their complex structures. We have developed a chemoenzymatic method for regioselective deprotection of monosaccharide substrates using engineered Bacillus megaterium cytochrome P450 (P450_(BM3)) demethylases that provides a highly efficient means to access valuable intermediates, which can be converted to a wide range of substituted monosaccharides and polysaccharides. Demethylases displaying high levels of regioselectivity toward a number of protected monosaccharides were identified using a combination of protein and substrate engineering, suggesting that this approach ultimately could be used in the synthesis of a wide range of substituted mono- and polysaccharides for studies in chemistry, biology, and medicine

Estimated South Dakota Land Use Change from 2006 to 2012

Grasslands play a key role in providing wildlife habitat and recreation, as well as in range and pasture livestock production systems by producing high quality animal protein for human consumption. Croplands provide high quality grains for human consumption, coarse grains for ethanol production, and along with forages, feed for confined livestock production systems. These livestock systems also produce high quality animal protein for human consumption. Both land use systems play important roles in a wide range of societal issues facing South Dakota including economic productivity and development, water quality and quantity, health of rural communities, urban development, and additional aspects of quality-of-life long associated with the state. The purpose of this study was to estimate land use changes in South Dakota from 2006 to 2012. Estimates of land use changes were calculated based on proportions of visually observed land use using high resolution imagery (\u3c 2-m resolution) at the same 14,400 sampling points in the years 2006 and 2012. Between 2006 and 2012, the estimated grassland losses were 1,837,100 acres (±21,100). Grassland losses resulted in increased acres devoted to cropland (1,439,500 acres ±15,600), roads + buildings (nonagricultural purposes, 27,400 acres ±110), wetlands + forest (habitat, 126,800 acres ±690), and open water (243,300 acres ±860). The consequences of changes in land use in South Dakota may impact a wide range of stakeholder and interest groups, as well as society in general

A Precision Calculation of the Next-to-Leading Order Energy-Energy Correlation Function

The O(alpha_s^2) contribution to the Energy-Energy Correlation function (EEC) of e+e- -> hadrons is calculated to high precision and the results are shown to be larger than previously reported. The consistency with the leading logarithm approximation and the accurate cancellation of infrared singularities exhibited by the new calculation suggest that it is reliable. We offer evidence that the source of the disagreement with previous results lies in the regulation of double singularities.Comment: 6 pages, uuencoded LaTeX and one eps figure appended Complete paper as PostScript file (125 kB) available at: http://www.phys.washington.edu/~clay/eecpaper1/paper.htm

Effect of channel block on the spiking activity of excitable membranes in a stochastic Hodgkin-Huxley model

The influence of intrinsic channel noise on the spontaneous spiking activity of poisoned excitable membrane patches is studied by use of a stochastic generalization of the Hodgkin-Huxley model. Internal noise stemming from the stochastic dynamics of individual ion channels is known to affect the collective properties of the whole ion channel cluster. For example, there exists an optimal size of the membrane patch for which the internal noise alone causes a regular spontaneous generation of action potentials. In addition to varying the size of ion channel clusters, living organisms may adapt the densities of ion channels in order to optimally regulate the spontaneous spiking activity. The influence of channel block on the excitability of a membrane patch of certain size is twofold: First, a variation of ion channel densities primarily yields a change of the conductance level. Second, a down-regulation of working ion channels always increases the channel noise. While the former effect dominates in the case of sodium channel block resulting in a reduced spiking activity, the latter enhances the generation of spontaneous action potentials in the case of a tailored potassium channel blocking. Moreover, by blocking some portion of either potassium or sodium ion channels, it is possible to either increase or to decrease the regularity of the spike train.Comment: 10 pages, 3 figures, published 200