263 research outputs found

    Escape rate and Hausdorff measure for entire functions

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    The escaping set of an entire function is the set of points that tend to infinity under iteration. We consider subsets of the escaping set defined in terms of escape rates and obtain upper and lower bounds for the Hausdorff measure of these sets with respect to certain gauge functions.Comment: 24 pages; some errors corrected, proof of Theorem 2 shortene

    Selective binding of facial features reveals dynamic expression fragments

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    The temporal correspondence between two arbitrarily chosen pairs of alternating features can generally be reported for rates up to 3–4 Hz. This limit is however surpassed for specialised visual mechanisms that encode conjunctions of features. Here we show that this 3–4 Hz limit is exceeded for eye gaze and eyebrow pairing, but not for eye gaze and mouth pairing, suggesting combined eye and eyebrow motion constitutes a dynamic expression fragment; a building block of superordinate facial actions

    Effects and predictors of shoulder muscle massage for patients with posterior shoulder tightness

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    Background: Clinical approaches like mobilization, stretching, and/or massage may decrease shoulder tightness and improve symptoms in subjects with stiff shoulders. We investigated the effect and predictors of effectiveness of massage in the treatment of patients with posterior shoulder tightness. ;Methods: A randomized controlled trial was conducted in a hospital-based outpatient practice (orthopedic and rehabilitation). Forty-three women and 17 men (mean age = 54 years, range 43-73 years) with posterior shoulder tightness participated and were randomized into massage and control groups (n = 30 per group). A physical therapist provided the massage on the posterior deltoid, infraspinatus, and teres minor of the involved shoulder for 18 minutes [about 6 minutes for each muscle] two times a week for 4 weeks. For the control group, one therapist applied light hand touch on the muscles 10 minutes two times a week for 4 weeks. Glenohumeral internal rotation ROM, functional status, and muscle tightness were the main outcomes. Additionally, the potential factors on the effectiveness of massage were analyzed by multivariate logistic regression. For this analysis, patients with functional score improvement at least 20% after massage were considered responsive, and the others were considered nonresponsive. ;Results: Fifty-two patients completed the study (29 for the massage and 23 for the control). The overall mean internal rotation ROM increased significantly in the massage group compared to the control (54.9 degrees v.s. 34.9 degrees; P <= 0.001). There were 21 patients in the responsive group and 8 in the nonresponsive group. Among the factors, duration of symptoms, functional score, and posterior deltoid tightness were significant predictors of effectiveness of massage. ;Conclusions: Massage was an effective treatment for patients with posterior shoulder tightness, but was less effective in patients with longer duration of symptoms, higher functional limitation, and less posterior deltoid tightness

    A randomised trial into the effect of an isolated hip abductor strengthening programme and a functional motor control programme on knee kinematics and hip muscle strength

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    Background: Dynamic knee valgus and internal femoral rotation are proposed to be contributory risk factors for patellofemoral pain and anterior cruciate ligament injuries. Multimodal interventions including hip abductor strengthening or functional motor control programmes have a positive impact of pain, however their effect on knee kinematics and muscle strength is less clear. The aim of this study was to examine the effect of isolated hip abductor strengthening and a functional motor control exercise on knee kinematics and hip abductor strength. Methods: This prospective, randomised, repeated measures design included 29 asymptomatic volunteers presenting with increase knee valgus and femoral internal rotation. Participants completed either isolated hip abductor strengthening or a functional motor control exercise for 5 weeks. Knee kinematics were measured using inertial sensors during 2 functional activities and hip abductor strength measured using a load cell during isometric hip abduction. Results: There were no significant differences in dynamic knee valgus and internal rotation following the isolated hip abductor or functional motor control intervention, and no significant differences between the groups for knee angles. Despite this, the actual magnitude of reduction in valgus was 10° and 5° for the functional motor control group and strengthening group respectively. The actual magnitude of reduction in internal rotation was 9° and 18° for the functional motor control group and strengthening group respectively. Therefore there was a tendency towards clinically significant improvements in knee kinematics in both exercise groups. A statistically significant improvement in hip abductor strength was evident for the functional motor control group (27% increase; p = 0.008) and strengthening group (35% increase; p = 0.009) with no significant difference between the groups being identified (p = 0.475). Conclusions: Isolated hip strengthening and functional motor control exercises resulted in non-statistically significant changes in knee kinematics, however there was a clear trend towards clinically meaningful reductions in valgus and internal rotation. Both groups demonstrated similar significant gains in hip abductor strength suggesting\ud either approach could be used to strengthen the hip abductors

    Chromosomal-level assembly of the Asian Seabass genome using long sequence reads and multi-layered scaffolding

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    We report here the ~670 Mb genome assembly of the Asian seabass (Lates calcarifer), a tropical marine teleost. We used long-read sequencing augmented by transcriptomics, optical and genetic mapping along with shared synteny from closely related fish species to derive a chromosome-level assembly with a contig N50 size over 1 Mb and scaffold N50 size over 25 Mb that span ~90% of the genome. The population structure of L. calcarifer species complex was analyzed by re-sequencing 61 individuals representing various regions across the species' native range. SNP analyses identified high levels of genetic diversity and confirmed earlier indications of a population stratification comprising three clades with signs of admixture apparent in the South-East Asian population. The quality of the Asian seabass genome assembly far exceeds that of any other fish species, and will serve as a new standard for fish genomics

    Short-term exposure to traffic-related air pollution and daily mortality in London, UK.

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    Epidemiological studies have linked daily concentrations of urban air pollution to mortality, but few have investigated specific traffic sources that can inform abatement policies. We assembled a database of >100 daily, measured and modelled pollutant concentrations characterizing air pollution in London between 2011 and 2012. Based on the analyses of temporal patterns and correlations between the metrics, knowledge of local emission sources and reference to the existing literature, we selected, a priori, markers of traffic pollution: oxides of nitrogen (general traffic); elemental and black carbon (EC/BC) (diesel exhaust); carbon monoxide (petrol exhaust); copper (tyre), zinc (brake) and aluminium (mineral dust). Poisson regression accounting for seasonality and meteorology was used to estimate the percentage change in risk of death associated with an interquartile increment of each pollutant. Associations were generally small with confidence intervals that spanned 0% and tended to be negative for cardiovascular mortality and positive for respiratory mortality. The strongest positive associations were for EC and BC adjusted for particle mass and respiratory mortality, 2.66% (95% confidence interval: 0.11, 5.28) and 2.72% (0.09, 5.42) per 0.8 and 1.0 μg/m(3), respectively. These associations were robust to adjustment for other traffic metrics and regional pollutants, suggesting a degree of specificity with respiratory mortality and diesel exhaust containing EC/BC

    Microanatomy of Adult Zebrafish Extraocular Muscles

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    Binocular vision requires intricate control of eye movement to align overlapping visual fields for fusion in the visual cortex, and each eye is controlled by 6 extraocular muscles (EOMs). Disorders of EOMs are an important cause of symptomatic vision loss. Importantly, EOMs represent specialized skeletal muscles with distinct gene expression profile and susceptibility to neuromuscular disorders. We aim to investigate and describe the anatomy of adult zebrafish extraocular muscles (EOMs) to enable comparison with human EOM anatomy and facilitate the use of zebrafish as a model for EOM research. Using differential interference contrast (DIC), epifluorescence microscopy, and precise sectioning techniques, we evaluate the anatomy of zebrafish EOM origin, muscle course, and insertion on the eye. Immunofluorescence is used to identify components of tendons, basement membrane and neuromuscular junctions (NMJs), and to analyze myofiber characteristics. We find that adult zebrafish EOM insertions on the globe parallel the organization of human EOMs, including the close proximity of specific EOM insertions to one another. However, analysis of EOM origins reveals important differences between human and zebrafish, such as the common rostral origin of both oblique muscles and the caudal origin of the lateral rectus muscles. Thrombospondin 4 marks the EOM tendons in regions that are highly innervated, and laminin marks the basement membrane, enabling evaluation of myofiber size and distribution. The NMJs appear to include both en plaque and en grappe synapses, while NMJ density is much higher in EOMs than in somatic muscles. In conclusion, zebrafish and human EOM anatomy are generally homologous, supporting the use of zebrafish for studying EOM biology. However, anatomic differences exist, revealing divergent evolutionary pressures

    Posterior shoulder tightness; an intersession reliability study of 3 clinical tests.

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    Background Although posterior shoulder tightness (PST) has been associated with shoulder pathology and altered glenohumeral joint kinematics, uncertainty remains regarding its cause and definition. To understand the efficacy of treatments for PST, it must be possible to identify people with PST for the purposes of research and clinical decision-making. Clinical tests for PST must demonstrate acceptable levels of measurement reliability in order to identify the condition and to evaluate the response to intervention. There is currently a lack of research describing intersession reliability for measures of PST. The aim of this study was to quantify the inter-session reliability for three clinical tests used to identify PST over a 6–10 week interval. Methods A convenience sample of 26 asymptomatic adult participants (52 shoulders) were recruited from a university setting over a five-month duration. Participants attended the human movement laboratory for measurement of glenohumeral joint internal rotation, horizontal adduction and low flexion on two occasions separated by an interval of 6–10 weeks. Intra-class correlation coefficients were calculated from the mean square values derived from the within-subject, single factor (repeated measures) ANOVA. Test-retest measurement stability was evaluated by calculating the standard error of measurement and the minimum detectable change for each measurement. Results All 3 tests demonstrated good intersession intra-rater reliability (0.86–0.88), and the standard error of measurement (95%) were 7.3° for glenohumeral horizontal adduction, 9.4° for internal rotation, and 6.9° for low flexion. The minimum detectable change for glenohumeral horizontal adduction was 10.2°, internal rotation was 13.3°, and low flexion was 9.7°. Conclusion In this population of people without symptoms, the 3 measures of PST all demonstrated acceptable inter-session reliability. The standard error of measurement and minimum detectable change results can be used to determine if a change in measures of PST are due to measurement error or an actual change over time.Peer reviewe

    A Developmental Systems Perspective on Epistasis: Computational Exploration of Mutational Interactions in Model Developmental Regulatory Networks

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    The way in which the information contained in genotypes is translated into complex phenotypic traits (i.e. embryonic expression patterns) depends on its decoding by a multilayered hierarchy of biomolecular systems (regulatory networks). Each layer of this hierarchy displays its own regulatory schemes (i.e. operational rules such as +/− feedback) and associated control parameters, resulting in characteristic variational constraints. This process can be conceptualized as a mapping issue, and in the context of highly-dimensional genotype-phenotype mappings (GPMs) epistatic events have been shown to be ubiquitous, manifested in non-linear correspondences between changes in the genotype and their phenotypic effects. In this study I concentrate on epistatic phenomena pervading levels of biological organization above the genetic material, more specifically the realm of molecular networks. At this level, systems approaches to studying GPMs are specially suitable to shed light on the mechanistic basis of epistatic phenomena. To this aim, I constructed and analyzed ensembles of highly-modular (fully interconnected) networks with distinctive topologies, each displaying dynamic behaviors that were categorized as either arbitrary or functional according to early patterning processes in the Drosophila embryo. Spatio-temporal expression trajectories in virtual syncytial embryos were simulated via reaction-diffusion models. My in silico mutational experiments show that: 1) the average fitness decay tendency to successively accumulated mutations in ensembles of functional networks indicates the prevalence of positive epistasis, whereas in ensembles of arbitrary networks negative epistasis is the dominant tendency; and 2) the evaluation of epistatic coefficients of diverse interaction orders indicates that, both positive and negative epistasis are more prevalent in functional networks than in arbitrary ones. Overall, I conclude that the phenotypic and fitness effects of multiple perturbations are strongly conditioned by both the regulatory architecture (i.e. pattern of coupled feedback structures) and the dynamic nature of the spatio-temporal expression trajectories displayed by the simulated networks

    Providing competency-based family medicine residency training in substance abuse in the new millennium: a model curriculum

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    <p>Abstract</p> <p>Background</p> <p>This article, developed for the Betty Ford Institute Consensus Conference on Graduate Medical Education (December, 2008), presents a model curriculum for Family Medicine residency training in substance abuse.</p> <p>Methods</p> <p>The authors reviewed reports of past Family Medicine curriculum development efforts, previously-identified barriers to education in high risk substance use, approaches to overcoming these barriers, and current training guidelines of the Accreditation Council for Graduate Medical Education (ACGME) and their Family Medicine Residency Review Committee. A proposed eight-module curriculum was developed, based on substance abuse competencies defined by Project MAINSTREAM and linked to core competencies defined by the ACGME. The curriculum provides basic training in high risk substance use to all residents, while also addressing current training challenges presented by U.S. work hour regulations, increasing international diversity of Family Medicine resident trainees, and emerging new primary care practice models.</p> <p>Results</p> <p>This paper offers a core curriculum, focused on screening, brief intervention and referral to treatment, which can be adapted by residency programs to meet their individual needs. The curriculum encourages direct observation of residents to ensure that core skills are learned and trains residents with several "new skills" that will expand the basket of substance abuse services they will be equipped to provide as they enter practice.</p> <p>Conclusions</p> <p>Broad-based implementation of a comprehensive Family Medicine residency curriculum should increase the ability of family physicians to provide basic substance abuse services in a primary care context. Such efforts should be coupled with faculty development initiatives which ensure that sufficient trained faculty are available to teach these concepts and with efforts by major Family Medicine organizations to implement and enforce residency requirements for substance abuse training.</p
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