Practice makes efficient: Effects of golf practice on brain activity

This study employed a test-retest design to examine changes in brain activity associated with practice of a motor skill. We recorded EEG activity from twelve right-handed recreational golfers (mean handicap: 23) as they putted 50 balls to a 2.4m distant hole, before and after a 3-day practice. We measured changes in putting performance, conscious processing, and regional EEG alpha activity. Putting performance improved and conscious processing decreased after practice. Mediation analyses revealed that performance improvements were associated with changes in EEG alpha, whereby activity in task-irrelevant cortical regions (temporal regions) was inhibited and functionally isolated from activity in task-relevant regions (central regions). These findings provide evidence for the development of greater neurophysiological efficiency with practice of a motor skill

Eye quietness and quiet eye in expert and novice golf performance: an electrooculographic analysis

Quiet eye (QE) is the final ocular fixation on the target of an action (e.g., the ball in golf putting). Camerabased eye-tracking studies have consistently found longer QE durations in experts than novices; however, mechanisms underlying QE are not known. To offer a new perspective we examined the feasibility of measuring the QE using electrooculography (EOG) and developed an index to assess ocular activity across time: eye quietness (EQ). Ten expert and ten novice golfers putted 60 balls to a 2.4 m distant hole. Horizontal EOG (2ms resolution) was recorded from two electrodes placed on the outer sides of the eyes. QE duration was measured using a EOG voltage threshold and comprised the sum of the pre-movement and post-movement initiation components. EQ was computed as the standard deviation of the EOG in 0.5 s bins from –4 to +2 s, relative to backswing initiation: lower values indicate less movement of the eyes, hence greater quietness. Finally, we measured club-ball address and swing durations. T-tests showed that total QE did not differ between groups (p = .31); however, experts had marginally shorter pre-movement QE (p = .08) and longer post-movement QE (p < .001) than novices. A group × time ANOVA revealed that experts had less EQ before backswing initiation and greater EQ after backswing initiation (p = .002). QE durations were inversely correlated with EQ from –1.5 to 1 s (rs = –.48 - –.90, ps = .03 - .001). Experts had longer swing durations than novices (p = .01) and, importantly, swing durations correlated positively with post-movement QE (r = .52, p = .02) and negatively with EQ from 0.5 to 1s (r = –.63, p = .003). This study demonstrates the feasibility of measuring ocular activity using EOG and validates EQ as an index of ocular activity. Its findings challenge the dominant perspective on QE and provide new evidence that expert-novice differences in ocular activity may reflect differences in the kinematics of how experts and novices execute skills

Clinical psychologists' use of transformative models of psychosis

Some theories (e.g. Jackson's Paradigm Shifting Hypothesis) and many personal accounts suggest that some psychotic crises, whilst distressing, can also be transformative, leading to growth and valued outcomes. However, little is known about the extent to which this idea informs mainstream mental health care. Clinical psychologists are influential advocates of psychosocial approaches more broadly: This study explored their use of transformative models. Twelve U.K. clinical psychologists were interviewed: Transcripts informed a grounded theory. No participants saw psychosis as a purely biological problem where the content of experiences is irrelevant. Two held a “biopsychosocial” model, viewing psychosis as an illness with psychosocial elements. Most either held a continuum view (i.e., schizotypy), in which psychosis proneness was also associated with positive attributes such as creativity or sensitivity, or a “fully psychological” view, seeing experiences as meaningful and/or as adaptive responses to events. Many believed that psychosis can be transformative in a broad sense, that is, lead to “post‐traumatic growth.” Some went further, believing that it can be a purposeful (e.g., an attempt, albeit painful and sometimes unsuccessful, to solve problems) or even a spiritual phenomenon. Participants' perspectives influenced their therapeutic approach: Those who saw experiences as purposeful were more likely to facilitate direct engagement with them and to support clients to explore potentially transformative aspects. However, this represented an extension of conventional approaches rather than being qualitatively different. More research is needed to clarify how widespread this approach is, to explore its utility, and to establish for whom and when it may be appropriate

A cross sectional study investigating the association between exposure to food outlets and childhood obesity in Leeds, UK.

Background: Current UK policy in relation to the influence of the ‘food environment’ on childhood obesity appears to be driven largely on assumptions or speculations because empirical evidence is lacking and findings from studies are inconsistent. The aim of this study was to investigate the number of food outlets and the proximity of food outlets in the same sample of children, without solely focusing on fast food. Methods: Cross sectional study over 3 years (n = 13,291 data aggregated). Body mass index (BMI) was calculated for each participant, overweight and obesity were defined as having a BMI >85th (sBMI 1.04) and 95th (sBMI 1.64) percentiles respectively (UK90 growth charts). Home and school neighbourhoods were defined as circular buffers with a 2 km Euclidean radius, centred on these locations. Commuting routes were calculated using the shortest straight line distance, with a 2 km buffer to capture varying routes. Data on food outlet locations was sourced from Leeds City Council covering the study area and mapped against postcode. Food outlets were categorised into three groups, supermarkets, takeaway and retail. Proximity to the nearest food outlet in the home and school environmental domain was also investigated. Age, gender, ethnicity and deprivation (IDACI) were included as covariates in all models. Results: There is no evidence of an association between the number of food outlets and childhood obesity in any of these environments; Home Q4 vs. Q1 OR = 1.11 (95% CI = 0.95-1.30); School Q4 vs. Q1 OR = 1.00 (95% CI 0.87 – 1.16); commute Q4 vs. Q1 OR = 0.1.00 (95% CI 0.83 – 1.20). Similarly there is no evidence of an association between the proximity to the nearest food outlet and childhood obesity in the home (OR = 0.77 [95% CI = 0.61 – 0.98]) or the school (OR = 1.01 [95% CI 0.84 – 1.23]) environment. Conclusions: This study provides little support for the notion that exposure to food outlets in the home, school and commuting neighbourhoods increase the risk of obesity in children. It seems that the evidence is not well placed to support Governmental interventions/recommendations currently being proposed and that policy makers should approach policies designed to limit food outlets with caution

Nicotine strongly activates dendritic cell-mediated adaptive immunity - potential role for progression of atherosclerotic lesions

Background - Antigen-presenting cells (APCs) such as monocytes and dendritic cells (DCs) stimulate T-cell proliferation and activation in the course of adaptive immunity. This cellular interaction plays a role in the growth of atherosclerotic plaques. Nicotine has been shown to increase the growth of atherosclerotic lesions. Therefore, we investigated whether nicotine can stimulate APCs and their T cell–stimulatory capacity using human monocyte–derived DCs and murine bone marrow–derived DCs as APCs. Methods and Results - Nicotine dose-dependently (10-8 to 10-4 mol/L) induced DC expression of costimulatory molecules (ie, CD86, CD40), MHC class II, and adhesion molecules (ie, LFA-1, CD54). Moreover, nicotine induced a 7.0-fold increase in secretion of the proinflammatory TH1 cytokine interleukin-12 by human DCs. These effects were abrogated by the nicotinic receptor antagonist -bungarotoxin and mecamylamine, respectively. The effects of nicotine were mediated in part by the phosphorylation of the PI3 kinase downstream target Akt and the mitogen-activated kinases ERK and p38 MAPK. Nicotine-stimulated APCs had a greater capacity to stimulate T-cell proliferation and cytokine secretion, as documented by mixed lymphocyte reactions and ovalbumin-specific assays with ovalbumin-transgenic DO10.11 mice. In a murine model of atherosclerosis, nicotine significantly enhanced the recruitment of DCs to atherosclerotic lesions in vivo. Conclusions - Nicotine activates DCs and augments their capacity to stimulate T-cell proliferation and cytokine secretion. These effects of nicotine may contribute to its influence on the progression of atherosclerotic lesions

Atomic layer etching of SiO2 with Ar and CHF 3 plasmas: A self-limiting process for aspect ratio independent etching

With ever increasing demands on device patterning to achieve smaller critical dimensions, the need for precise, controllable atomic layer etching (ALE) is steadily increasing. In this work, a cyclical fluorocarbon/argon plasma is successfully used for patterning silicon oxide by ALE in a conventional inductively coupled plasma tool. The impact of plasma parameters and substrate electrode temperature on the etch performance is established. We achieve the self-limiting behavior of the etch process by modulating the substrate temperature. We find that at an electrode temperature of −10°C, etching stops after complete removal of the modified surface layer as the residual fluorine from the reactor chamber is minimized. Lastly, we demonstrate the ability to achieve independent etching, which establishes the potential of the developed cyclic ALE process for small scale device patterning

Ionizing radiation fluctuations and large-scale structure in the Lyman-alpha forest

We investigate the large-scale inhomogeneities of the hydrogen ionizing radiation field in the Universe at redshift z=3. Using a raytracing algorithm, we simulate a model in which quasars are the dominant sources of radiation. We make use of large scale N-body simulations of a LambdaCDM universe, and include such effects as finite quasar lifetimes and output on the lightcone, which affects the shape of quasar light echoes. We create Lya forest spectra that would be generated in the presence of such a fluctuating radiation field, finding that the power spectrum of the Lya forest can be suppressed by as much as 15 % for modes with k=0.05-1 Mpc/h. This relatively small effect may have consequences for high precision measurements of the Lya power spectrum on larger scales than have yet been published. We also investigate another radiation field probe, the cross-correlation of quasar positions and the Lya forest. For both quasar lifetimes which we simulate (10^7 yr and 10^8 yr), we expect to see a strong decrease in the Lya absorption close to other quasars (the ``foreground'' proximity effect). We then use data from the Sloan Digital Sky Survey First Data Release to make an observational determination of this statistic. We find no sign of our predicted lack of absorption, but instead increased absorption close to quasars. If the bursts of radiation from quasars last on average < 10^6 yr, then we would not expect to be able to see the foreground effect. However, the strength of the absorption itself seems to be indicative of rare objects, and hence much longer total times of emission per quasar. Variability of quasars in bursts with timescales > 10^4yr and < 10^6 yr could reconcile these two facts.Comment: Submitted to ApJ, 21 pages, 17 postscript figures, emulateapj.st

Measurement of the Spatial Cross-Correlation Function of Damped Lyman Alpha Systems and Lyman Break Galaxies

We present the first spectroscopic measurement of the spatial cross-correlation function between damped Lyman alpha systems (DLAs) and Lyman break galaxies (LBGs). We obtained deep u'BVRI images of nine QSO fields with 11 known z ~ 3 DLAs and spectroscopically confirmed 211 R < 25.5 photometrically selected z > 2 LBGs. We find strong evidence for an overdensity of LBGs near DLAs versus random, the results of which are similar to that of LBGs near other LBGs. A maximum likelihood cross-correlation analysis found the best fit correlation length value of r_0 = 2.9^(+1.4)_(-1.5) h^(-1)Mpc using a fixed value of gamma = 1.6. The implications of the DLA-LBG clustering amplitude on the average dark matter halo mass of DLAs are discussed.Comment: 12 pages, 2 figures, accepted for publication in Astrophysical Journal Letter

Spin-one ferromagnets with single-ion anisotropy in a perpendicular external field

In this paper, the conventional Holstein-Primakoff method is generalized with the help of the characteristic angle transformation [Lei Zhou and Ruibao Tao, J. Phys. A {\bf 27} 5599 (1994)] for the spin-one magnetic systems with single-ion anisotropies. We find that the weakness of the conventional method for such systems can be overcome by the new approach. Two models will be discussed to illuminate the main idea, which are the ``easy-plane" and the ``easy-axis" spin-one ferromagnet, respectively. Comparisons show that the current approach can give reasonable ground state properties for the magnetic system with ``easy-plane" anisotropy though the conventional method never can, and can give a better representation than the conventional one for the magnetic system with ``easy-axis" anisotropy though the latter is usually believed to be a good approximation in such case. Study of the easy-plane model shows that there is a phase transition induced by the external field, and the low-temperature specific heat may have a peak as the field reaches the critical value.Comment: Using LaTex. To be published in the September 1 issue of Physical Review B (1996). Email address: [email protected]