Long-Term Stability of Baseline Impact Scores in High School Football Players across Age Groups

In recent decades, the increased awareness of the prevalence of concussions has resulted in significant advancements in concussion assessment and treatment, including annual or bi-annual pre-season computerized baseline assessments. However, limited research has focused on the differences in stability of baseline neurocognitive performance among different age groups in adolescence. The main purpose of the present study was to explore the long-term stability of ImPACT baseline assessments across one-year intervals in multiple age groups within a sample of high school football players. Subjects who completed two baseline assessments between the ages of 14 and 17 who had completed two baselines one year apart were selected from a de-identified archival database. Subjects were separated into three groups based on age at first baseline (i.e., 14, 15, and 16). Results indicate differences in baseline performance stability between age groups, with younger athletes demonstrating improvements in performance consistent with ongoing cognitive development and older athletes demonstrating more stability in performance. Importantly, the Reaction Time composite score remained stable among all groups. Results also provide evidence for wide ranging Reliable Change Indices across all age groups, which can make it difficult to interpret meaningful change after injury for those whose baseline was completed one year ago. These findings indicate younger athletes (i.e., 14- and 15-year-olds) should ideally complete baselines prior to each athletic season (e.g., fall, winter, spring), whereas older athletes (e.g., 16-year-olds) should complete baselines annually. The use of more frequent baselines aims to increase clinicians’ ability to detect clinically meaningful change following concussion, which in turn would lead to increased accuracy in return-to-play decision making. However, it is also important to recognize potential pitfalls of increased baseline testing (e.g., practice effects, lack of available resources), which are discussed. When recent baselines are not available, these results indicate the Reaction Time composite may serve as an important indicator of departure from baseline given its demonstrated stability across groups. In addition to clinical implications, the present results are consistent with Luria’s theory of cognitive development which indicates some cognitive skills continue to develop throughout adolescence along with corresponding cortical areas. Lastly, these results provide some information regarding the cognitive development of high school football players within the context of repeated exposure to sub-concussive impacts, though such conclusions are limited be the absence of a control group

A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars

We present radial velocities, equivalent widths, model atmosphere parameters, and abundances or upper limits for 53 species of 48 elements derived from high resolution optical spectroscopy of 313 metal-poor stars. A majority of these stars were selected from the metal-poor candidates of the HK Survey of Beers, Preston, and Shectman. We derive detailed abundances for 61% of these stars for the first time. Spectra were obtained during a 10-year observing campaign using the Magellan Inamori Kyocera Echelle spectrograph on the Magellan Telescopes at Las Campanas Observatory, the Robert G. Tull Coude Spectrograph on the Harlan J. Smith Telescope at McDonald Observatory, and the High Resolution Spectrograph on the Hobby-Eberly Telescope at McDonald Observatory. We perform a standard LTE abundance analysis using MARCS model atmospheres, and we apply line-by-line statistical corrections to minimize systematic abundance differences arising when different sets of lines are available for analysis. We identify several abundance correlations with effective temperature. A comparison with previous abundance analyses reveals significant differences in stellar parameters, which we investigate in detail. Our metallicities are, on average, lower by approx. 0.25 dex for red giants and approx. 0.04 dex for subgiants. Our sample contains 19 stars with [Fe/H] < -3.5, 84 stars with [Fe/H] < -3.0, and 210 stars with [Fe/H] < -2.5. Detailed abundances are presented here or elsewhere for 91% of the 209 stars with [Fe/H] < -2.5 as estimated from medium resolution spectroscopy by Beers, Preston, and Shectman. We will discuss the interpretation of these abundances in subsequent papers.Comment: Accepted for publication in the Astronomical Journal. 60 pages, 59 figures, 18 tables. Machine-readable versions of the long tables can be found in the ancillary data file

The Abundances Of Neutron-Capture Species In The Very Metal-Poor Globular Cluster M15: A Uniform Analysis Of Red Giant Branch And Red Horizontal Branch Stars

The globular cluster M15 is unique in its display of star-to-star variations in the neutron-capture elements. Comprehensive abundance surveys have been previously conducted for handfuls of M15 red giant branch (RGB) and red horizontal branch (RHB) stars. No attempt has been made to perform a single, self-consistent analysis of these stars, which exhibit a wide range in atmospheric parameters. In the current effort, a new comparative abundance derivation is presented for three RGB and six RHB members of the cluster. The analysis employs an updated version of the line transfer code MOOG, which now appropriately treats coherent, isotropic scattering. The apparent discrepancy in the previously reported values for the metallicity of M15 RGB and RHB stars is addressed and a resolute disparity of Delta(RHB-RGB) approximate to 0.1 dex in the iron abundance was found. The anti-correlative behavior of the light neutron-capture elements (Sr, Y, Zr) is clearly demonstrated with both Ba and Eu, standard markers of the s- and r-process, respectively. No conclusive detection of Pb was made in the RGB targets. Consequently for the M15 cluster, this suggests that the main component of the s-process has made a negligible contribution to those elements normally dominated by this process in solar system material. Additionally for the M15 sample, a large Eu abundance spread is confirmed, which is comparable to that of the halo field at the same metallicity. These abundance results are considered in the discussion of the chemical inhomogeneity and nucleosynthetic history of M15.National Science Foundation AST 07-07447, AST 09-08978Astronom

The new onset of dysphagia four years after anterior cervical discectomy and fusion: Case report and literature review.

Background: Dysphagia is a common complication immediately following anterior cervical spine surgery. However, its onset more than 1-year postoperatively is rare. Case Description: A 45-year-old male initially underwent a C3-4 and C5-6 anterior cervical discectomy and fusion (ACDF). At age 49, 4 years later, he presented with worsening dysphagia accompanied by neck and right upper extremity pain. Radiographs demonstrated an extruded left C3 screw, which had migrated into the prevertebral soft tissues at the C4-C5 level; there was also loosening of the right C3 screw. The subsequent barium swallow study revealed that the screw was embedded in the pharyngeal wall. The patient required a two-stage operation; first, to remove the anterior instrumentation, and second, to perform a posterior instrumented C2-T2 fusion. Conclusion: A barium swallow study and other dynamic imaging are a valuable component of the diagnostic workup and therapeutic intervention to evaluate the delayed onset dysphagia following an ACDF

Open Rotor Tone Shielding Methods for System Noise Assessments Using Multiple Databases

Advanced aircraft designs such as the hybrid wing body, in conjunction with open rotor engines, may allow for significant improvements in the environmental impact of aviation. System noise assessments allow for the prediction of the aircraft noise of such designs while they are still in the conceptual phase. Due to significant requirements of computational methods, these predictions still rely on experimental data to account for the interaction of the open rotor tones with the hybrid wing body airframe. Recently, multiple aircraft system noise assessments have been conducted for hybrid wing body designs with open rotor engines. These assessments utilized measured benchmark data from a Propulsion Airframe Aeroacoustic interaction effects test. The measured data demonstrated airframe shielding of open rotor tonal and broadband noise with legacy F7/A7 open rotor blades. Two methods are proposed for improving the use of these data on general open rotor designs in a system noise assessment. The first, direct difference, is a simple octave band subtraction which does not account for tone distribution within the rotor acoustic signal. The second, tone matching, is a higher-fidelity process incorporating additional physical aspects of the problem, where isolated rotor tones are matched by their directivity to determine tone-by-tone shielding. A case study is conducted with the two methods to assess how well each reproduces the measured data and identify the merits of each. Both methods perform similarly for system level results and successfully approach the experimental data for the case study. The tone matching method provides additional tools for assessing the quality of the match to the data set. Additionally, a potential path to improve the tone matching method is provided

System Noise Assessment and the Potential for a Low Noise Hybrid Wing Body Aircraft with Open Rotor Propulsion

An aircraft system noise assessment was conducted for a hybrid wing body freighter aircraft concept configured with three open rotor engines. The primary objective of the study was to determine the aircraft system level noise given the significant impact of installation effects including shielding the open rotor noise by the airframe. The aircraft was designed to carry a payload of 100,000 lbs on a 6,500 nautical mile mission. An experimental database was used to establish the propulsion airframe aeroacoustic installation effects including those from shielding by the airframe planform, interactions with the control surfaces, and additional noise reduction technologies. A second objective of the study applied the impacts of projected low noise airframe technology and a projection of advanced low noise rotors appropriate for the NASA N+2 2025 timeframe. With the projection of low noise rotors and installation effects, the aircraft system level was 26.0 EPNLdB below Stage 4 level with the engine installed at 1.0 rotor diameters upstream of the trailing edge. Moving the engine to 1.5 rotor diameters brought the system level noise to 30.8 EPNLdB below Stage 4. At these locations on the airframe, the integrated level of installation effects including shielding can be as much as 20 EPNLdB cumulative in addition to lower engine source noise from advanced low noise rotors. And finally, an additional set of technology effects were identified and the potential impact at the system level was estimated for noise only without assessing the impact on aircraft performance. If these additional effects were to be included it is estimated that the potential aircraft system noise could reach as low as 38.0 EPNLdB cumulative below Stage 4

Influence of urbanisation and garden plants on the diversity and abundance of aphids and their ladybird and hoverfly predators

Urban gardens can harbour a high diversity of insects, which are critically important components of urban ecosystems. In this work, we investigate the richness and diversity of a major taxon of economic and ecological importance, the aphids (Homoptera: Aphididae), and their main insect predators, the hoverflies (Diptera: Syrphidae) and ladybirds (Coleoptera: Coccinellidae), in urban gardens. We examined how variation in environmental factors associated with urbanisation (garden host plant abundance, garden plant richness, garden size, proportion of impervious surfaces in the surrounding area) directly and indirectly (via prey and predator abundance) influence the local diversity and abundance of aphids, ladybirds, and hoverflies. Sixty-seven domestic gardens located in southern England were surveyed during the peak period of aphid abundance, and the numbers and identity of aphids and their predators were recorded. We observed 45 aphid species (179917 individuals in total), 15 hoverfly species (494 individuals) and 8 ladybird species (173 individuals). We found that aphid species richness and abundance were positively associated with utilised host plant abundance and garden plant species richness. Hoverfly abundance was positively correlated with garden plant richness. The abundance of ladybirds was positively correlated with aphid abundance and garden plant species richness, and negatively associated to the proportion of impervious surfaces in the surrounding environment. The difference in responses between the two major taxa of aphid predators may reflect differences in their behaviour and natural history. Our results indicate that overall increases in urban land cover are not favourable for ladybirds as a group, and that fine scale habitat variables that are determined by garden owners have the potential to greatly affect the general diversity of aphids and their main predators

MARbLE:Multi-Agent Reinforcement Learning at the Edge for Digital Agriculture

Digital agriculture, hailed as the fourth great agricultural revolution, employs software-driven autonomous agents for in-field crop management. Edge computing resources deployed near crop fields support autonomous agents with substantial computational needs for tasks such as AI inference. In large fields, using multiple autonomous agents, called swarms, can speed up crop management tasks if sufficient edge resources are provisioned. However, to use swarms today, farmers and software developers craft their own standalone solutions that are either simple and ineffective or complicated and hard-to-reproduce. We present MARbLE, a platform for developing and managing swarms. MARbLE provides an easy-to-use programming paradigm that helps users build swarm workloads using multi-agent reinforcement learning. Developers supply just two functions Map() and Eval(). The platform automatically compiles and deploys swarms and continuously updates the reinforcement learning models that govern their actions. Developers can experiment with multiple swarm and edge resource configurations both in simulation and with actual in-field runs. We studied real UAV swarms conducting digital agriculture missions. We observe that swarms demanded edge computing resources in bursts; the ratio of average to peak demand was 2.9X. MARbLE uses energy-saving load balancing policies to duty cycle machines during workload demand troughs, leveraging workload patterns to save edge energy. Using MARbLE, we found that four-agent swarms with load balancing techniques sped up missions by 2.1X and reduced edge energy usage by up to 2X compared to state of the art autonomous swarms