Children's understanding of the knowledge prerequisites of drawing and pretending.

Many young children will claim that someone is pretending to be something even when the person does not know what that something is. To examine whether children's failure to take knowledge prerequisites into account is part of a more fundamental problem in recognizing how mental representations constrain external ones, the authors asked children whether an artist who did not know what something was, yet whose drawing bore resemblance to it, was drawing it. The same questions were asked regarding pretending. Children performed similarly on pretending and drawing questions, and performance on both questions improved when the protagonists' point of view was emphasized. Performance for drawing improved somewhat when alternative goals were stated. Further, cross-sectional data indicated that understanding how knowledge relates to producing external representations increases gradually from age 4 to age 8, suggesting that experiential factors may be crucial to this understanding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopamine release and uptake rates both decrease in the partially denervated striatum in proportion to the loss of dopamine terminals

We have identified on the membranes of the locomotory muscle of Ascaris suum an amastatin-sensitive aminopeptidase that hydrolyses the bioactive neuropeptides AF1 (KNEFIRF-NH2) and AF2 (KHEYLRF-NH2), by cleavage of the Lys1-Asn2 and Lys1-His2 peptide bonds, respectively. AF2 (1.2 nmol of HEYLRF-NH2 formed min[-1] (mg protein[-1])) was hydrolysed at a faster rate compared to AF1 (0.2 nmol of NEFIRF-NH2 formed min[-1] (mg protein[-1])). AF1 hydrolysis by the aminopeptidase was inhibited by the amastatin (IC50, 9.0 microM), leuhistin (IC50, 1.25 microM) but was insensitive to puromycin, indicating a similarity to mammalian aminopeptidase N. The enzyme was also inhibited by arphamenine B (IC50, 9.0 microM), (2S, 3R)-3-amino-2-hydroxy-4-(4-nitrophenyl)butanoyl-L-leucine (IC50, 8.0 microM), bestatin (IC50, 15.0 microM) and 1 mM 1-10 bis-phenanthroline. The detergent Triton X-100 solubilised enzyme had a pI of 5.0 and after 1000-fold purification by ion-exchange chromatography, appeared to have a Mr of around 240,000 by SDS-PAGE. The purified aminopeptidase had a Km of 534 microM for the hydrolysis of AF1 and cleaved Phe1 from FMRF-NH2, but was unable to hydrolyse DFMRF-NH2 or FDMRF-NH2. The aminopeptidase that we have described in this report might have a role in the extracellular metabolism and inactivation of neuropeptides acting on the locomotory muscle of A. suum.     

A Multinomial Model of Event-Based Prospective Memory.

Prospective memory is remembering to perform an action in the future. The authors introduce the 1st formal model of event-based prospective memory, namely, a multinomial model that includes 2 separate parameters related to prospective memory processes. The 1st measures preparatory attentional processes, and the 2nd measures retrospective memory processes. The model was validated in 4 experiments. Manipulations of instructions to place importance on either the prospective memory task or the background task (Experiments 1 and 2) and manipulations of distinctiveness of prospective memory targets (Experiment 2) had expected effects on model parameters, as did a manipulation of the difficulty of prospective memory target encoding (Experiments 3 and 4). An alternative model was also evaluated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adolescent pregnancy and parenthood: Recent evidence and future directions.

An overview of recent research on adolescent sexual activity, pregnancy, and parenthood is presented, with a focus on the dearth of knowledge concerning psychological precursors and consequences. Although the rate of teenage childbearing has decreased substantially this century, increasing rates of sexual activity, illegitimacy, and welfare receipt raise public concerns. New research is discussed that suggests that many negative outcomes previously ascribed to mothers' age are as much causes or correlates of teenage pregnancy as effects of it, although this claim is less substantiated regarding effects on children of teenage mothers. Literature on fathers and grandmothers is summarized, and suggestions are made for furthering this research. An overview is given of recent successes among intervention programs, and policy implications of the new federal welfare law are considered for teenage mothers and their children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scanning electrochemical microscopy of model neurons: constant distance imaging

Undifferentiated and differentiated PC12 cells were imaged with the constant-distance mode of scanning electrochemical microscopy (SECM) using carbon ring and carbon fiber tips. Two types of feedback signals were used for distance control: the electrolysis current of a mediator (constant-current mode) and the impedance measured by the SECM tip (constant-impedance mode). The highest resolution was achieved using carbon ring electrodes with the constant-current mode. However, the constant-impedance mode has the important advantages that topography and faradaic current can be measured simultaneously, and because no mediator is required, the imaging can take place directly in the cell growth media. It was found that vesicular release events do not measurably alter the impedance, but the depolarizing solution, 105 mM K+, produces a dramatic impedance change such that constant-distance imaging cannot be performed during application of the stimulus. However, by operating the tip in the constant-height mode, cell morphology (via a change in impedance) and vesicular release could be detected simultaneously while moving the tip across the cell. This work represents a significant improvement over previous SECM imaging of model neurons, and it demonstrates that the combination of amperometry and constant-impedance SECM has the potential to be a powerful tool for investigating the spatial distribution of neurotransmitter release in vitro.     

Can Reconstructed Se-Deficient Line Defects in Monolayer VSe2 Induce Magnetism?

There have been several recent conflicting reports on the ferromagnetism of clean monolayer VSe₂. Herein, the controllable formation of 1D defect line patterns in vanadium diselenide (VSe₂) monolayers initiated by thermal annealing is presented. Using scanning tunneling microscopy and q-plus atomic force microscopy techniques, the 1D line features are determined to be 8-member-ring arrays, formed via a Se deficient reconstruction process. The reconstructed VSe₂ monolayer with Se-deficient line defects displays room-temperature ferromagnetism under X-ray magnetic circular dichroism and magnetic force microscopy, consistent with the density functional theory calculations. This study possibly resolves the controversy on whether ferromagnetism is intrinsic in monolayer VSe₂, and highlights the importance of controlling and understanding the atomic structures of surface defects in 2D crystals, which could play key roles in the material properties and hence potential device applications.     

Enhanced multi-spectral imaging of live breast cancer cells using immunotargeted gold nanoshells and two-photon excitation microscopy

We demonstrate the capability of using immunotargeted gold nanoshells as contrast agents for in vitro two-photon microscopy. The two-photon luminescence properties of different-sized gold nanoshells are first validated using near-infrared excitation at 780?nm. The utility of two-photon microscopy as a tool for imaging live HER2-overexpressing breast cancer cells labeled with anti-HER2-conjugated nanoshells is then explored and imaging results are compared to normal breast cells. Five different imaging channels are simultaneously examined within the emission wavelength range of 451-644?nm. Our results indicate that under near-infrared excitation, superior contrast of SK-BR-3 cancer cells labeled with immunotargeted nanoshells occurs at an emission wavelength ranging from 590 to 644?nm. Luminescence from labeled normal breast cells and autofluorescence from unlabeled cancer and normal cells remain imperceptible under the same conditions.     

Using Policy and Regulatory Frameworks to Facilitate Water Transitions

There are persistent calls across policy, industry and academia for urban water transitions in order to deliver increased sustainability, liveability and resilience. However, realisation of such transformational change is difficult, and there are a number of undesirable or unsuccessful transition trajectories that can manifest. Drawing on a contemporary stormwater quality management transition in South-East Queensland, Australia, this qualitative research paper provides an empirical exploration of a transition in struggle. The paper examines why and how this transition trajectory unfolded, focusing specifically on the evolution of culture, structure and practice changes from the 1970s to the present-day. The paper makes two scholarly contributions, firstly confirming the dynamic nature of transformational change and indicating the need to design transition initiatives across the culture, structure and practice domains to co-evolve and thereby build a robust and mutually reinforcing transition foundation. The results also reveal the critical role of regulation in providing a safety net for the transition and enabling continued progress even when commitment to policy goals wavers. These results also provide practical insight for practitioners engaged in the implementation of transition processes, and reveal the need for transition advocates to deliberately and proactively engage with regulatory frameworks to embed a novel practice.