Population connectivity shifts at high frequency within an open-coast marine protected area network.

A complete understanding of population connectivity via larval dispersal is of great value to the effective design and management of marine protected areas (MPA). However empirical estimates of larval dispersal distance, self-recruitment, and within season variability of population connectivity patterns and their influence on metapopulation structure remain rare. We used high-resolution otolith microchemistry data from the temperate reef fish Hypsypops rubicundus to explore biweekly, seasonal, and annual connectivity patterns in an open-coast MPA network. The three MPAs, spanning 46 km along the southern California coastline were connected by larval dispersal, but the magnitude and direction of connections reversed between 2008 and 2009. Self-recruitment, i.e. spawning, dispersal, and settlement to the same location, was observed at two locations, one of which is a MPA. Self-recruitment to this MPA ranged from 50-84%; within the entire 60 km study region, self-recruitment accounted for 45% of all individuals settling to study reefs. On biweekly time scales we observed directional variability in alongshore current data and larval dispersal trajectories; if viewed in isolation these data suggest the system behaves as a source-sink metapopulation. However aggregate biweekly data over two years reveal a reef network in which H. rubicundus behaves more like a well-mixed metapopulation. As one of the few empirical studies of population connectivity within a temperate open coast reef network, this work can inform the MPA design process, implementation of ecosystem based management plans, and facilitate conservation decisions

Health Literacy in Context—Settings, Media, and Populations

To date, most published health literacy research has focused on assessing and improving personal skills and abilities. More recently, a better understanding has emerged of the extent to which these skills and abilities are mediated by environmental demands and situational complexities — the context in which health literacy is developed and applied. This has led to much greater attention being given to ways of reducing the situational demands and complexity in which an individual makes a health decision. This collection of papers examines current progress in understanding health literacy "in context", by improving our understanding of the mutual impact of a range of social, economic, environmental, and organisational influences on health literacy. These papers provide unique and original perspectives on the concept, distribution, and application of health literacy in very diverse populations, offering cultural insights and a clear indication of the impact of social and environmental context on health literacy. These perspectives include an examination of differing national policy responses to health literacy illustrating how policy and practice can (and should) respond to this more complete but complex understanding of health literacy. Other papers look at the application of new digital media and the creative harnessing of popular culture as routes to extend the reach and customisation of communications. These papers also illustrate good progress in the evolution of research in the contexts in which health literacy is developed and applied, as well as signaling some areas in which more research would be useful

Intermediate-mass Black Hole and stellar orbits in the Galactic Center

Many young stars reside within the central half-parsec from SgrA*, the supermassive black hole in the Galactic Center. The origin of these stars remains a puzzle. Recently, Hansen and Milosavljevic (2003, HM) have argued that an Intermediate-Mass Black Hole (IMBH) could have delivered the young stars to the immediate vicinity of SgrA*. Here we focus on the final stages of the HM scenario. Namely, we integrate numerically the orbits of stars which are initially bound to the IMBH, but are stripped from it by the tidal field of SgrA*. Our numerical algorithm is a symplectic integrator designed specifically for the problem at hand; however, we have checked our results with SYMBA, a version of the widely available SWIFT code. We find that the distribution of the post-inspiral orbital parameters is sensitive to the eccentricity of the inspiraling IMBH. If the IMBH is on a circular orbit, then the inclinations of numerically computed orbits relative to the inspiral plane are almost always smaller than 10 degrees, and therefore (a) the simulations are in good agreement with the observed motions of stars in a clockwise-moving stellar disc, (b) the simulations never reproduce the orbits of stars outside this disc, which include those in the second thick ring of stars and the randomly oriented unrelaxed orbits of some of the S-stars. If the IMBH's orbital eccentricity is e=0.6, then approximately half of the stars end up with orbital inclinations below 10 degrees, and another half have inclinations anywhere between 0 and 180 degrees; this is somewhat closer to what's observed. We also show that if IRS13 cluster is bound by an IMBH, as has been argued by Maillard et. al. 2004, then the same IMBH could not have delivered all of the young stars to their present location.Comment: 16 pages, 10 figure

Ariel - Volume 12(13) Number 4

Co-Editors Gary Fishbein Lynn Solomon Business Manager Rich Davis Assistant Business Manager Jeff Lavanier Layout Editors Paul J. Berlin Tracy A. Glauser Photography Editor Ben Alma

The antisaccade task as an index of sustained goal activation in working memory: modulation by nicotine

The antisaccade task provides a laboratory analogue of situations in which execution of the correct behavioural response requires the suppression of a more prepotent or habitual response. Errors (failures to inhibit a reflexive prosaccade towards a sudden onset target) are significantly increased in patients with damage to the dorsolateral prefrontal cortex and patients with schizophrenia. Recent models of antisaccade performance suggest that errors are more likely to occur when the intention to initiate an antisaccade is insufficiently activated within working memory. Nicotine has been shown to enhance specific working memory processes in healthy adults. MATERIALS AND METHODS: We explored the effect of nicotine on antisaccade performance in a large sample (N = 44) of young adult smokers. Minimally abstinent participants attended two test sessions and were asked to smoke one of their own cigarettes between baseline and retest during one session only. RESULTS AND CONCLUSION: Nicotine reduced antisaccade errors and correct antisaccade latencies if delivered before optimum performance levels are achieved, suggesting that nicotine supports the activation of intentions in working memory during task performance. The implications of this research for current theoretical accounts of antisaccade performance, and for interpreting the increased rate of antisaccade errors found in some psychiatric patient groups are discussed

Scalar Levin-Type Sequence Transformations

Sequence transformations are important tools for the convergence acceleration of slowly convergent scalar sequences or series and for the summation of divergent series. Transformations that depend not only on the sequence elements or partial sums $s_n$ but also on an auxiliary sequence of so-called remainder estimates $\omega_n$ are of Levin-type if they are linear in the $s_n$, and nonlinear in the $\omega_n$. Known Levin-type sequence transformations are reviewed and put into a common theoretical framework. It is discussed how such transformations may be constructed by either a model sequence approach or by iteration of simple transformations. As illustration, two new sequence transformations are derived. Common properties and results on convergence acceleration and stability are given. For important special cases, extensions of the general results are presented. Also, guidelines for the application of Levin-type sequence transformations are discussed, and a few numerical examples are given.Comment: 59 pages, LaTeX, invited review for J. Comput. Applied Math., abstract shortene

Acute effects of nicotine on visual search tasks in young adult smokers

Rationale Nicotine is known to improve performance on tests involving sustained attention and recent research suggests that nicotine may also improve performance on tests involving the strategic allocation of attention and working memory. Objectives We used measures of accuracy and response latency combined with eye-tracking techniques to examine the effects of nicotine on visual search tasks. Methods In experiment 1 smokers and non-smokers performed pop-out and serial search tasks. In experiment 2, we used a within-subject design and a more demanding search task for multiple targets. In both studies, 2-h abstinent smokers were asked to smoke one of their own cigarettes between baseline and tests. Results In experiment 1, pop-out search times were faster after nicotine, without a loss in accuracy. Similar effects were observed for serial searches, but these were significant only at a trend level. In experiment 2, nicotine facilitated a strategic change in eye movements resulting in a higher proportion of fixations on target letters. If the cigarette was smoked on the first trial (when the task was novel), nicotine additionally reduced the total number of fixations and refixations on all letters in the display. Conclusions Nicotine improves visual search performance by speeding up search time and enabling a better focus of attention on task relevant items. This appears to reflect more efficient inhibition of eye movements towards task irrelevant stimuli, and better active maintenance of task goals. When the task is novel, and therefore more difficult, nicotine lessens the need to refixate previously seen letters, suggesting an improvement in working memory

Activation of Ventral Tegmental Area 5-HT2C Receptors Reduces Incentive Motivation

FUNDING AND DISCLOSURE The research was funded by Wellcome Trust (WT098012) to LKH; and National Institute of Health (DK056731) and the Marilyn H. Vincent Foundation to MGM. The University of Michigan Transgenic Core facility is partially supported by the NIH-funded University of Michigan Center for Gastrointestinal Research (DK034933). The remaining authors declare no conflict of interest. ACKNOWLEDGMENTS We thank Dr Celine Cansell, Ms Raffaella Chianese and the staff of the Medical Research Facility for technical assistance. We thank Dr Vladimir Orduña for the scientific advice and technical assistance.Peer reviewedPublisher PD

Direction and magnitude of nicotine effects on the fMRI BOLD response are related to nicotine effects on behavioral performance

Considerable variability across individuals has been reported in both the behavioral and fMRI blood oxygen level-dependent (BOLD) response to nicotine. We aimed to investigate (1) whether there is a heterogeneous effect of nicotine on behavioral and BOLD responses across participants and (2) if heterogeneous BOLD responses are associated with behavioral performance measures. In this double-blind, placebo-controlled, cross-over study, 41 healthy participants (19 smokers)—drawn from a larger population-based sample—performed a visual oddball task after acute challenge with 1 mg nasal nicotine. fMRI data and reaction time were recorded during performance of the task. Across the entire group of subjects, we found increased activation in the anterior cingulate cortex, middle frontal gyrus, superior temporal gyrus, post-central gyrus, planum temporal and frontal pole in the nicotine condition compared with the placebo condition. However, follow-up analyses of this difference in activation between the placebo and nicotine conditions revealed that some participants showed an increase in activation while others showed a decrease in BOLD activation from the placebo to the nicotine condition. A reduction of BOLD activation from placebo to nicotine was associated with a decrease in reaction time and reaction time variability and vice versa, suggesting that it is the direction of BOLD response to nicotine which is related to task performance. We conclude that the BOLD response to nicotine is heterogeneous and that the direction of response to nicotine should be taken into account in future pharmaco-fMRI research on the central action of nicotine

Quantitative cross-species extrapolation between humans and fish: The case of the anti-depressant fluoxetine

This article has been made available through the Brunel Open Access Publishing Fund.Fish are an important model for the pharmacological and toxicological characterization of human pharmaceuticals in drug discovery, drug safety assessment and environmental toxicology. However, do fish respond to pharmaceuticals as humans do? To address this question, we provide a novel quantitative cross-species extrapolation approach (qCSE) based on the hypothesis that similar plasma concentrations of pharmaceuticals cause comparable target-mediated effects in both humans and fish at similar level of biological organization (Read-Across Hypothesis). To validate this hypothesis, the behavioural effects of the anti-depressant drug fluoxetine on the fish model fathead minnow (Pimephales promelas) were used as test case. Fish were exposed for 28 days to a range of measured water concentrations of fluoxetine (0.1, 1.0, 8.0, 16, 32, 64 μg/L) to produce plasma concentrations below, equal and above the range of Human Therapeutic Plasma Concentrations (HTPCs). Fluoxetine and its metabolite, norfluoxetine, were quantified in the plasma of individual fish and linked to behavioural anxiety-related endpoints. The minimum drug plasma concentrations that elicited anxiolytic responses in fish were above the upper value of the HTPC range, whereas no effects were observed at plasma concentrations below the HTPCs. In vivo metabolism of fluoxetine in humans and fish was similar, and displayed bi-phasic concentration-dependent kinetics driven by the auto-inhibitory dynamics and saturation of the enzymes that convert fluoxetine into norfluoxetine. The sensitivity of fish to fluoxetine was not so dissimilar from that of patients affected by general anxiety disorders. These results represent the first direct evidence of measured internal dose response effect of a pharmaceutical in fish, hence validating the Read-Across hypothesis applied to fluoxetine. Overall, this study demonstrates that the qCSE approach, anchored to internal drug concentrations, is a powerful tool to guide the assessment of the sensitivity of fish to pharmaceuticals, and strengthens the translational power of the cross-species extrapolation