201 research outputs found

    Intrinsic symmetry groups of links with 8 and fewer crossings

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    We present an elementary derivation of the "intrinsic" symmetry groups for knots and links of 8 or fewer crossings. The standard symmetry group for a link is the mapping class group \MCG(S^3,L) or \Sym(L) of the pair (S3,L)(S^3,L). Elements in this symmetry group can (and often do) fix the link and act nontrivially only on its complement. We ignore such elements and focus on the "intrinsic" symmetry group of a link, defined to be the image Σ(L)\Sigma(L) of the natural homomorphism \MCG(S^3,L) \rightarrow \MCG(S^3) \cross \MCG(L). This different symmetry group, first defined by Whitten in 1969, records directly whether LL is isotopic to a link L′L' obtained from LL by permuting components or reversing orientations. For hyperbolic links both \Sym(L) and Σ(L)\Sigma(L) can be obtained using the output of \texttt{SnapPea}, but this proof does not give any hints about how to actually construct isotopies realizing Σ(L)\Sigma(L). We show that standard invariants are enough to rule out all the isotopies outside Σ(L)\Sigma(L) for all links except 7627^2_6, 81328^2_{13} and 8538^3_5 where an additional construction is needed to use the Jones polynomial to rule out "component exchange" symmetries. On the other hand, we present explicit isotopies starting with the positions in Cerf's table of oriented links which generate Σ(L)\Sigma(L) for each link in our table. Our approach gives a constructive proof of the Σ(L)\Sigma(L) groups.Comment: 72 pages, 66 figures. This version expands the original introduction into three sections; other minor changes made for improved readabilit

    Jack Voltaic 3.0 Cyber Research Report Executive Summary

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    This condensed Executive summary provides an overview of the information contained in the full JV 3.0 Cyber Research Report

    The physiological stress response to anaerobic exercise is altered following sodium bicarbonate supplementation

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    Sodium bicarbonate (NaHCO3) is a nutritional aid that is proposed to enhance performance by reducing the state of exercise induced acidosis, however research is currently equivocal. Despite this, most research still focuses on its effects upon performance, and not whether the reduced acidosis impacts upon any other factors related to exercise. There is some research to suggest that such a reduction in [H+] can attenuate a number of physiological stress pathways such as stress hormones (1, 4), heat shock protein 72 (HSP72) and oxidative stress (3), suggesting a potential role in exercise recovery. However there are some limitations with this previous research as work intensities were not controlled for, hence making comparisons between treatments difficult. Also limited markers of stress were measured despite the physiological stress response being multi-faceted. The aim of this study was to examine whether the ingestion of NaHCO3 would influence the expression of several markers of stress measured simultaneously, following a work controlled anaerobic exercise

    Rehabilitation Treatment Specification System for Voice Therapy: Application to Everyday Clinical Care

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    PURPOSE: Rehabilitation intervention descriptions often do not explicitly identify active ingredients or how those ingredients lead to changes in patient functioning. The Rehabilitation Treatment Specification System (RTSS) provides guidance to identify the critical aspects of any rehabilitation therapy and supported the development of standardly named ingredients and targets in voice therapy (Rehabilitation Treatment Specification System for Voice Therapy [RTSS-Voice]). This study sought to test the content validity of the RTSS-Voice and determine if the RTSS-Voice can be used to identify commonalities and differences in treatment (criterion validity) across clinicians in everyday clinical practice. METHOD: Five speech-language pathologists from different institutions videotaped one therapy session for 59 patients diagnosed with a voice or upper airway disorder. Specifications were created for each video, and iterative rounds of revisions were completed with the treating clinician and two RTSS experts until consensus was reached on each specification. RESULTS: All 59 sessions were specified without the addition of any targets or ingredients. There were two frequent targets: (a) increased volition and (b) decreased strained voice quality. There were three frequent ingredients: (a) information regarding the patient\u27s capability and motivation to perform a therapeutic behavior, (b) knowledge of results feedback, and (c) opportunities to practice voicing with improved resonance and mean airflow. Across sessions treating vocal hyperfunction, there was large variability across clinicians regarding the types and number of treatment components introduced, types of feedback provided, and vocal practice within spontaneous speech and negative practice. CONCLUSIONS: The RTSS and the RTSS-Voice demonstrated strong content validity, as they comprehensively characterized 59 therapy sessions. They also demonstrated strong criterion validity, as commonalities and differences were identified in everyday voice therapy for vocal hyperfunction across multiple clinicians. Future work to translate RTSS principles and RTSS-Voice terms into clinical documentation can help to understand how clinician and patient variability impacts outcomes and bridge the research-practice gap. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.24796875

    Jack Voltaic 3.0 Cyber Research Report

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    The Jack Voltaic (JV) Cyber Research project is an innovative, bottom-up approach to critical infrastructure resilience that informs our understanding of existing cybersecurity capabilities and identifies gaps. JV 3.0 contributed to a repeatable framework cities and municipalities nationwide can use to prepare. This report on JV 3.0 provides findings and recommendations for the military, federal agencies, and policy makers

    Cardiovascular Fitness and Creativity in Children

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    Creativity permeates virtually all aspects of humanity, as human-made creations and connections are all around us. Another common human phenomenon is aerobic exercise, and its corresponding, longer-term condition, cardiovascular fitness. Multiple studies support cardiovascular fitness as a positive correlate of, and aerobic exercise as an inducer of, cognitive benefits and both structural and functional brain changes, across ages and species. From an understanding of the relationships between aerobic exercise/cardiovascular fitness and certain neurocognitive changes, along with an understanding of the neural processes underlying creativity, a theoretical psychophysiological relationship between aerobic exercise/cardiovascular fitness and creativity appears. There is indirect support that neural and behavioral changes induced by exercise, or consistent with high cardiovascular fitness, may result in improved creativity. However, there is currently little research examining this relationship. Additionally, the relationship of aerobic exercise/cardiovascular fitness and creativity has seemingly been unexamined in children. In this study, cardiovascular fitness levels of eight 9-11 year olds, as determined by a maximal oxygen consumption test, were related to both the number and uniqueness of appropriate responses in creativity tasks. There were no significant correlations between cardiovascular fitness and these creativity measures. The limited sample size hindered the ability to ascertain a more complete analysis of these relationships. Future research should include a larger sample size, take into consideration factors such as motivation, sleep, and stress, and perform neuroimaging. These would allow a more comprehensive understanding of the relationship between cardiovascular fitness and creativity.Ope

    The Spatial and Temporal Structure of Neural Activity across the Fly Brain

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    What are the spatial and temporal scales of brainwide neuronal activity? We used swept, confocally-aligned planar excitation (SCAPE) microscopy to image all cells in a large volume of the brain of adult Drosophila with high spatiotemporal resolution while flies engaged in a variety of spontaneous behaviors. This revealed neural representations of behavior on multiple spatial and temporal scales. The activity of most neurons correlated (or anticorrelated) with running and flailing over timescales that ranged from seconds to a minute. Grooming elicited a weaker global response. Significant residual activity not directly correlated with behavior was high dimensional and reflected the activity of small clusters of spatially organized neurons that may correspond to genetically defined cell types. These clusters participate in the global dynamics, indicating that neural activity reflects a combination of local and broadly distributed components. This suggests that microcircuits with highly specified functions are provided with knowledge of the larger context in which they operate

    Resting state functional connectivity provides mechanistic predictions of future changes in sedentary behavior

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    Sedentary behaviors are increasing at the cost of millions of dollars spent in health care and productivity losses due to physical inactivity-related deaths worldwide. Understanding the mechanistic predictors of sedentary behaviors will improve future intervention development and precision medicine approaches. It has been posited that humans have an innate attraction towards effort minimization and that inhibitory control is required to overcome this prepotent disposition. Consequently, we hypothesized that individual differences in the functional connectivity of brain regions implicated in inhibitory control and physical effort decision making at the beginning of an exercise intervention in older adults would predict the change in time spent sedentary over the course of that intervention. In 143 healthy, low-active older adults participating in a 6-month aerobic exercise intervention (with three conditions: walking, dance, stretching), we aimed to use baseline neuroimaging (resting state functional connectivity of two a priori defined seed regions), and baseline accelerometer measures of time spent sedentary to predict future pre-post changes in objectively measured time spent sedentary in daily life over the 6-month intervention. Our results demonstrated that functional connectivity between (1) the anterior cingulate cortex and the supplementary motor area and (2) the right anterior insula and the left temporoparietal/temporooccipital junction, predicted changes in time spent sedentary in the walking group. Functional connectivity of these brain regions did not predict changes in time spent sedentary in the dance nor stretch and tone conditions, but baseline time spent sedentary was predictive in these conditions. Our results add important knowledge toward understanding mechanistic associations underlying complex out-of-session sedentary behaviors within a walking intervention setting in older adults

    Francisella tularensis in the United States

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    Subpopulations A.I and A.II. of Francisella tularensis subsp. tularensis are associated with unique biotic and abiotic factors that maintain disease foci
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