386 research outputs found

    Intraocular pressure fluctuations in professional brass and woodwind musicians during common playing conditions.

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    BACKGROUND: We investigated the effects on intraocular pressure (IOP) and blood pressure (BP) of playing brass and woodwind instruments by monitoring IOP and BP in a representative group of professional musicians under a variety of common playing conditions. METHODS: IOP and BP measurements were recorded from 37 brass and 15 woodwind instrument players, before and after playing tones of low, middle and high frequency. We also measured IOP and BP before and during playing common exercises of 10 minutes duration, as well as after playing a sustained high-pitched tone, to test for changes in IOP under conditions of maximum effort. RESULTS: Playing tones on brass and woodwind instruments causes a temporary elevation in IOP and BP, depending on the tone frequency: brass instrument players showed a significant elevation after playing high and middle frequency tones (p < 0.0001) whereas woodwind instrument players showed a significant increase only for high frequencies (e.g., oboe, 17 ± 2.9 mm Hg to 21 ± 4.4 mm Hg; p = 0.017). Playing a typical exercise of 10 minutes temporarily increased IOP in both groups of musicians. Finally, playing a sustained tone of high pitch caused a significant elevation in IOP in brass instrument players only (16.6 ± 3.5 mm Hg to 23.3 ± 8.9 mm Hg; p < 0.0001). CONCLUSIONS: The temporary and sometimes dramatic elevations and fluctuations in IOP observed in this study, coupled with daily exposure to instrument play, puts professional wind instrument players at increased risk of developing glaucoma. Consequently, these musicians should be monitored for signs of glaucoma, especially those with co-existing risk factors

    Shape recognition: convexities, concavities and things in between.

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    Visual objects are effortlessly recognized from their outlines, largely irrespective of viewpoint. Previous studies have drawn different conclusions regarding the importance to shape recognition of specific shape features such as convexities and concavities. However, most studies employed familiar objects, or shapes without curves, and did not measure shape recognition across changes in scale and position. We present a novel set of random shapes with well-defined convexities, concavities and inflections (intermediate points), segmented to isolate each feature type. Observers matched the segmented reference shapes to one of two subsequently presented whole-contour shapes (target or distractor) that were re-scaled and re-positioned. For very short segment lengths, performance was significantly higher for convexities than for concavities or intermediate points and for convexities remained constant with increasing segment length. For concavities and intermediate points, performance improved with increasing segment length, reaching convexity performance only for long segments. No significant differences between concavities and intermediates were found. These results show for the first time that closed curvilinear shapes are encoded using the positions of convexities, rather than concavities or intermediate regions. A shape-template model with no free parameters gave an excellent account of the data

    Author Correction: Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases.

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    Emmanuelle Souzeau, who contributed to analysis of data, was inadvertently omitted from the author list in the originally published version of this Article. This has now been corrected in both the PDF and HTML versions of the Article

    Proton Transfer, Hydrogen Bonding, and Disorder: Nitrogen Near-Edge X-ray Absorption Fine Structure and X-ray Photoelectron Spectroscopy of Bipyridine-Acid Salts and Co-crystals

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    The sensitivity of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to Brønsted donation and the protonation state of nitrogen in the solid state is investigated through a series of multicomponent bipyridine–acid systems alongside X-ray photoelectron spectroscopy (XPS) data. A large shift to high energy occurs for the 1s → 1π* resonance in the nitrogen K-edge NEXAFS with proton transfer from the acid to the bipyridine base molecule and allows assignment as a salt (C═NH+), with the peak ratio providing the stoichiometry of the types of nitrogen species present. A corresponding binding energy shift for C═NH+ is observed in the nitrogen XPS, clearly identifying protonation and formation of a salt. The similar magnitude shifts observed with both techniques relative to the unprotonated nitrogen of co-crystals (C═N) suggest that the chemical state (initial-state) effects dominate. Results from both techniques reveal the sensitivity to identify proton transfer, hydrogen bond disorder, and even the potential to distinguish variations in hydrogen bond length to nitrogen

    Investigating Age-Related Decline in Sensorimotor Control Using Robotic Tasks

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    Background Aging is linked to widespread changes in sensorimotor control, leading to functional decline, mobility limitations, and an increased risk of falls. Certain aspects of the neurological examination and assessment of the motor system are subjective, underscoring the need for objective and quantitative tools to evaluate sensorimotor performance.Methods To address this, we designed three experimental tasks using the vBOT planar robotic manipulandum to compare sensorimotor performance in healthy young adults (\u3c35 years) and older adults (\u3e60 years). Unlike previous assessments, our tasks uniquely integrate simultaneous bimanual control and altered dynamic conditions to comprehensively assess sensorimotor capabilities. The first task involved a bimanual de novo motor learning paradigm in which participants coordinated both hands to control a virtual 2D arm and performed 400 center-out and out-to-center trials. The second task assessed unimanual control using the right hand to perform center-out movements to eight targets. It introduced dynamic forces simulating object manipulation during the final 200 trials. The third task was similar but applied a viscous force field in the last 200 trials. It also included a scoring mechanism rewarding brisk movements, thereby encouraging participants to perform closer to their maximum capabilities. In this task, performance was also compared between the dominant and non-dominant arms. Group comparisons and within-subject differences were evaluated using appropriate statistical analyses.Results Each task effectively identified age-related differences, but the viscous resistance task proved particularly sensitive, capturing significant age-related declines in force generation and movement duration. This scoring approach likely amplified performance differences, highlighting its suitability for detecting subtle effects of aging.Older adults generally showed slower movement, longer task completion times, reduced peak forces, and prolonged reaction times. However, individual performance varied, with some older participants performing on par with younger individuals. In the third experiment, the dominant arm showed consistently better performance than the non-dominant arm, underscoring the sensitivity of the metrics to lateralized differences in motor control.Conclusions These findings suggest that robot-based tasks have potential to quantify age-related differences in sensorimotor control and may support more precise clinical assessments.Significance Statement This study utilizes a robotic manipulandum, i.e., the vBOT, to assess the effect of aging. Through precisely controlled repeatable sensorimotor tasks, we quantify movement characteristics in both younger and older adults, providing clear insights into age-related motor decline. Our approach not only highlights the magnitude and variability of functional changes with age but also establishes rigorous and reliable quantitative benchmarks that could serve as critical tools for evaluating preventative therapies. In turn, this could guide the development of interventions aimed at preserving motor performance in older age.News & Noteworthy This study introduces a novel approach to assessing how aging affects movement dynamics using a robotic system. As populations age, understanding sensorimotor decline becomes increasingly crucial. Unlike conventional assessments, our method quantifies motor control metrics with precision, revealing previously undetectable, subtle age-related changes in movement efficiency, reaction times, and force generation. This framework establishes a rigorous benchmark for evaluating age-related decline, offering valuable clinical applications and informing the design of interventions to support older adults

    A systematic review and evaluation of statistical methods for group variable selection

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    This review condenses the knowledge on variable selection methods implemented in R and appropriate for datasets with grouped features. The focus is on regularized regressions identified through a systematic review of the literature, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 14 methods are discussed, most of which use penalty terms to perform group variable selection. Depending on how the methods account for the group structure, they can be classified into knowledge and data-driven approaches. The first encompass group-level and bi-level selection methods, while two-step approaches and collinearity-tolerant methods constitute the second category. The identified methods are briefly explained and their performance compared in a simulation study. This comparison demonstrated that group-level selection methods, such as the group minimax concave penalty, are superior to other methods in selecting relevant variable groups but are inferior in identifying important individual variables in scenarios where not all variables in the groups are predictive. This can be better achieved by bi-level selection methods such as group bridge. Two-step and collinearity-tolerant approaches such as elastic net and ordered homogeneity pursuit least absolute shrinkage and selection operator are inferior to knowledge-driven methods but provide results without requiring prior knowledge. Possible applications in proteomics are considered, leading to suggestions on which method to use depending on existing prior knowledge and research question

    Trapping virtual pores by crystal retro-engineering

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    Stable guest-free porous molecular crystals are uncommon. By contrast, organic molecular crystals with guest-occupied cavities are frequently observed, but these cavities tend to be unstable and collapse on removal of the guests—this feature has been referred to as ‘virtual porosity’. Here, we show how we have trapped the virtual porosity in an unstable low-density organic molecular crystal by introducing a second molecule that matches the size and shape of the unstable voids. We call this strategy ‘retro-engineering’ because it parallels organic retrosynthetic analysis, and it allows the metastable two-dimensional hexagonal pore structure in an organic solvate to be trapped in a binary cocrystal. Unlike the crystal with virtual porosity, the cocrystal material remains single crystalline and porous after removal of guests by heating

    Isotopomeric polymorphism in a "doubly-polymorphic" multi-component molecular crystal

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    Isotopomeric polymorphism is observed in complexes of isonicotinamide with oxalic acid, highly unusual here in that each isotopic complex is itself polymorphic, a situation of “double polymorphism”. The four polymorphic forms exhibit different degrees of hydron transfer.</p

    Non-linear global pooling in the discrimination of circular and non-circular shapes

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    The ability to discriminate minute deviations from circularity is dependent upon global summation mechanisms integrating information along entire contours. The aim of this study was to determine how the strength of global summation depends on various stimulus features. To determine if the strength of global summation differs between shapes, contour discrimination for various contour shapes, generated by applying a sinusoidal modulation to the radius of a circle (radial frequency - RF - patterns), was measured. Shapes differed in frequency (number of lobes RF3, RF5 and RF20) and amplitude ('sharpness' of the lobes ranged between 0 and 20× thresholds for detecting deviation from a circle). Low amplitudes test discrimination against a circle while high amplitudes measure sensitivity for highly non-circular shapes (e.g. five-pointed star-shapes). The ability to integrate information along contours was assessed by comparing the effect of applying radial deformations to the entire contour or to only fractions (various number of cycles). Results show that discrimination thresholds remain in the hyperacuity range for low amplitudes, but increase for higher amplitudes. Concerning signal integration, discrimination, expressed as a function of the amount of contour deformed, exhibits a shallow and a steep regime. Discrimination improves only slowly as more contour cycles are deformed until the point when the entire pattern is modulated, when sensitivity increases substantially. The initial shallow regime is well captured by probability summation. The increase in sensitivity when the entire pattern is modulated compared to a single cycle provides evidence for global pooling. The pattern of integration and the existence of global pooling is dependent on shape frequency. The two-part behavior is independent of shape amplitude but is only seen for low RFs (3 and 5). Data for RF20 follow the prediction of probability summation.We next investigated various stimulus characteristics and their effect on integration strength. Global pooling exceeding probability summation is evident for different pattern sizes, presentation times and for high as well as low absolute contrasts. Only if the contrasts of different fractions of a contour shape are individually scaled to match their respective visibilities is integration strength below the level of probability summation. This explains the lack of apparent global pooling in previous studies employing mixed contrasts.The marked increase in performance for discriminating completely modulated RF patterns argues in favor of highly specialized, global shape mechanisms that are seen over a wide range of stimulus configurations. The results indicate global, non-linear mechanisms, which respond most strongly when stimulated by the entire pattern and comparatively weakly when only stimulated by parts of it.</p

    Frequency of cataract surgery and its impact on visual function : results from the German Gutenberg Health Study

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    PURPOSE To determine the frequency of cataract surgery in Germany and to evaluate its impact on visual function in an adult population. METHODS The population-based Gutenberg Health Study was conducted in Germany with its baseline examination between 2007 and 2012 and a 5-year follow-up examiantion. An ophthalmological examination including slit-lamp examination, ocular biometry, and Scheimpflug imaging was carried out. Overall and age-specific frequencies of unilateral and bilateral cataract surgery within 5 years were computed including the 95% confidential intervals [95%-CI]. Association analyses were conducted to determine social and ocular associated factors using multivariable logistic regression analysis. Vision-related quality of life was assessed using NEI VFQ-25. RESULTS A total of 10,544 people aged 35 to 74 years were bilateral phakic at baseline and had information on lens status at the 5-year examination. Of these, 168 had unilateral cataract surgery (1.6% [1.4–1.9%]), and 448 had bilateral cataract surgery (4.2% [3.9–4.7%]) in the following 5 years. The frequency of cataract surgery increased with age: 45–54-year-old subjects had twice as often cataract surgery (in at least on eye: OR = 2.32) than at age 35–44 years. The frequency further strongly increases with age (55–64 years: OR = 10.5; 65–74 years: OR = 43.8, p < 0.001). Subjects with glaucoma were more likely to have cataract surgery (OR = 2.52, p < 0.001). Visual function increased when undergoing bilateral cataract surgery. CONCLUSIONS The frequency of cataract surgery is low at younger ages and increases up to 26% at age 70–74 years. Persons with glaucoma are more likely to undergo cataract surgery at population-based level in Germany
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