1,163 research outputs found

    Do Three Different Passive Assessments of Quadriceps Spasticity Relate to the Functional Activity of Walking for Children Diagnosed with Cerebral Palsy?

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    A stiff-knee gait pattern is frequently associated with several impairments including quadriceps spasticity in children diagnosed with cerebral palsy (CP). The relationship of clinical measures of quadriceps spasticity and the stiff-knee gait pattern in children diagnosed with CP has not been well established. Therefore, the purpose of this study was to determine the ability of clinical measures of quadriceps spasticity (modified Ashworth scale [MAS], Ely tests, and pendulum test) to categorize a stiff-knee gait pattern in children with CP. Children were categorized as having a stiff-knee gait pattern based on kinematic and EMG gait data. Results of a logistic regression model revealed that the only significant measure was A1 of the pendulum test. Discriminant analysis functions were used to predict group membership (stiff-knee, not stiff-knee gait pattern) for each measure. The A1 of the pendulum test demonstrated the highest classification accuracy and the highest sensitivity compared to the other measures. Therefore, a negative pendulum test (indicated by an A1 value of 45 degrees or more) is more useful for ruling out a stiff-knee gait pattern compared to the other clinical measures

    Do Three Different Passive Assessments of Quadriceps Spasticity Relate to the Functional Activity of Walking for Children Diagnosed with Cerebral Palsy?

    Get PDF
    A stiff-knee gait pattern is frequently associated with several impairments including quadriceps spasticity in children diagnosed with cerebral palsy (CP). The relationship of clinical measures of quadriceps spasticity and the stiff-knee gait pattern in children diagnosed with CP has not been well established. Therefore, the purpose of this study was to determine the ability of clinical measures of quadriceps spasticity (modified Ashworth scale [MAS], Ely tests, and pendulum test) to categorize a stiff-knee gait pattern in children with CP. Children were categorized as having a stiff-knee gait pattern based on kinematic and EMG gait data. Results of a logistic regression model revealed that the only significant measure was A1 of the pendulum test. Discriminant analysis functions were used to predict group membership (stiff-knee, not stiff-knee gait pattern) for each measure. The A1 of the pendulum test demonstrated the highest classification accuracy and the highest sensitivity compared to the other measures. Therefore, a negative pendulum test (indicated by an A1 value of 45 degrees or more) is more useful for ruling out a stiff-knee gait pattern compared to the other clinical measures

    A Hot Spot in Coma

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    We study the temperature structure of the central part (r<18' ~0.7 h50**-1 Mpc) of the Coma cluster of galaxies using ASCA data. Two different analysis methods produce results in good agreement with each other and reveal the presence of interesting structures in the gas temperature distribution. Globally, the average temperature in the center of the cluster is 9.0 +/- 0.6 keV in good agreement with previous results. Superimposed on this, we find a cool area with temperatures of 4-6 keV associated with a filament of X-ray emission extending southeast from the cluster center detected by Vikhlinin and coworkers. We also find a hot spot with a temperature of around 13 keV displaced north from the central peak of emission. The distribution of the gas temperatures and relative specific entropies suggests that the cool features are most likely gas stripped from a galaxy group centered on NGC 4874 falling toward the core from outside, while the hot spot located ``ahead'' of this in-falling gas is due to shock heating. Thus our results suggest that we are observing Coma during a minor merger with a small group of galaxies associated with NGC 4874 shortly before the initial core passage.Comment: 5 pages, 2 figures, accepted for publication in the Astrophysical Journa

    Sex-Biased Gene Flow Among Elk in the Greater Yellowstone Ecosystem

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    We quantified patterns of population genetic structure to help understand gene flow among elk populations across the Greater Yellowstone Ecosystem. We sequenced 596 base pairs of the mitochondrial control region of 380 elk from eight populations. Analysis revealed high mitochondrial DNA variation within populations, averaging 13.0 haplotypes with high mean gene diversity (0.85). The genetic differentiation among populations for mitochondrial DNA was relatively high (FST = 0.161; P = 0.001) compared to genetic differentiation for nuclear microsatellite data (FST = 0.002; P = 0.332), which suggested relatively low female gene flow among populations. The estimated ratio of male to female gene flow (mm/mf = 46) was among the highest we have seen reported for large mammals. Genetic distance (for mitochondrial DNA pairwise FST) was not significantly correlated with geographic (Euclidean) distance between populations (Mantel’s r = 0.274, P = 0.168). Large mitochondrial DNA genetic distances (e.g., FST . 0.2) between some of the geographically closest populations (,65 km) suggested behavioral factors and/or landscape features might shape female gene flow patterns. Given the strong sex-biased gene flow, future research and conservation efforts should consider the sexes separately when modeling corridors of gene flow or predicting spread of maternally transmitted diseases. The growing availability of genetic data to compare male vs. female gene flow provides many exciting opportunities to explore the magnitude, causes, and implications of sex-biased gene flow likely to occur in many species

    Inspection of the Math Model Tools for On-Orbit Assessment of Impact Damage Report

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    In Spring of 2005, the NASA Engineering Safety Center (NESC) was engaged by the Space Shuttle Program (SSP) to peer review the suite of analytical tools being developed to support the determination of impact and damage tolerance of the Orbiter Thermal Protection Systems (TPS). The NESC formed an independent review team with the core disciplines of materials, flight sciences, structures, mechanical analysis and thermal analysis. The Math Model Tools reviewed included damage prediction and stress analysis, aeroheating analysis, and thermal analysis tools. Some tools are physics-based and other tools are empirically-derived. Each tool was created for a specific use and timeframe, including certification, real-time pre-launch assessments, and real-time on-orbit assessments. The tools are used together in an integrated strategy for assessing the ramifications of impact damage to tile and RCC. The NESC teams conducted a peer review of the engineering data package for each Math Model Tool. This report contains the summary of the team observations and recommendations from these reviews

    ID, GPS Tracking, 24/7 Tag Link for CubeSats and Constellations: Flight Results

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    The tiny 40-gram EyeStar-Tag processor, GPS, and radio link will ID its satellite with GPS and critical status data within a minute after turn-on. The autonomous low power EyeStar Tag GPS (20mW for 3D lock) is now at TRL-9 based on the successful release and operation of the Spaceflight Inc. ring on the 1/24/2021 rideshare launch. The orbit (530 km polar) was projected using GPS seven element arrays to generate, on the fly, the future ephemeris predictions while monitoring critical fight systems. The Tag continues to transmit over the Globalstar network of satellites and ground stations the GPS elements and status with low latency of seconds, even if the primary satellite fails or stops. Whether dead or alive, orbital elements and TLEs for debris tracking, attitude, and ID are available to the 18th Squadron. AFWERX’s SBIR investment helped fast track the Black Box and Tag systems. Key enablers and new architecture are flight referenced for 30 ThinSat constellation launched in February 2021 NG-15. With the Globalstar constellation NSL can monitor a satellite 24/7 anywhere in LEO orbits with data available anytime, without the need for expensive ground stations. With a 100% success in orbit using the NSL EyeStar processor and Globalstar comm systems (110+ radios in space with several tumbling) can contribute to the commercial, educational, and research small satellite market that is rapidly growing. The EyeStar radio is ideal for the next step to advance many NASA, DOD, commercial, and STEM satellites now that appropriate FCC, NTIA, and ITU licenses have all been approved. The aircraft Black Box is well known and is essential for crash diagnostics after the fact, but in addition, the satellite Black Box and processor will operate in Telemetry Tracking and Command (TT&C) mode during the whole mission and will continue TT&C in orbit after a completed or failed mission. The Black Box transmits vital data, health and safety information, GPS, and summary data while in orbit for 24/7 coverage. With its included solar arrays, the Black Box would operate for many years after the primary satellite fails so that essential data and tracking is continuous, and altitude known. If the satellite reawakens after some long failure, the Black Box reports the new status, and the satellite may be reactivated. NSL customers have experienced this wake-up mode after a year on one of our Black Box/EyeStar communication processors after an unexpected two-month “dead” phase and wake. The “dead” satellite was reactivated

    NESC Peer-Review of the Flight Rationale for Expected Debris Report

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    Since the loss of Columbia on February 1, 2003, the Space Shuttle Program (SSP) has significantly improved the understanding of launch and ascent debris, implemented hardware modifications to reduce debris, and conducted tests and analyses to understand the risks associated with expected debris. The STS-114 flight rationale for expected debris relies on a combination of all three of these factors. A number of design improvements have been implemented to reduce debris at the source. The External Tank (ET) thermal protection system (TPS) foam has been redesigned and/or process improvements have been implemented in the following locations: the bipod closeout, the first ten feet of the liquid hydrogen (LH2) tank protuberance air load (PAL) ramp, and the LH2 tank-to-intertank flange closeout. In addition, the forward bipod ramp has been eliminated and heaters have been installed on the bipod fittings and the liquid oxygen (LO2) feedline forward bellows to prevent ice formation. The Solid Rocket Booster (SRB) bolt catcher has been redesigned. The Orbiter reaction control system (RCS) thruster cover "butcher paper" has been replaced with a material that sheds at a low velocity. Finally, the pad area has been cleaned to reduce debris during lift-off

    Imperfect Tests, Pervasive Pathogens, and Variable Demographic Performance: Thoughts on Managing Bighorn Sheep Respiratory Disease

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    Respiratory disease (pneumonia) has been a persistent challenge for bighorn sheep (Ovis canadensis) conservation and its cause has been attributed to numerous bacteria including Mycoplasma ovipneumoniae and several Pasteurellaceae family species. This study sought to investigate efficacy of diagnostic protocols in detecting Pasteurellaceae and Mycoplasma ovipneumoniae, generate sampling recommendations for different protocols, assess the distribution of these disease agents among 17 bighorn sheep populations in Montana and Wyoming, and evaluate what associations existed between detection of these agents and demographic performance of bighorn sheep populations. Analysis of replicate samples from individual bighorn sheep revealed that detection probability for regularlyused diagnostic protocols was generally low (&lt;50%) for Pasteurellaceae and was high (&gt;70%) for Mycoplasma ovipneumoniae, suggesting that routine pathogen sampling likely mischaracterizes respiratory pathogen communities. Power analyses found that most pathogen species could be detected with 80% confidence at the population-level by conducting regularly-used protocols multiple times per animal. Each pathogen species was detected in over half of the study populations, but after accounting for detection probability there was low confidence in negative test results for populations where Pasteurellaceae species were not detected. Seventy-six percent of study populations hosted both Mycoplasma ovipneumoniae and Pasteurellaceae pathogens, yet a number of these populations were estimated to have positive population growth rates and recruitment rates greater than 30%. Overall, the results of this work suggest that bighorn sheep respiratory disease may be mitigated by manipulating population characteristics and respiratory disease epizootics could be caused by pathogens already resident in bighorn sheep population

    The impact of siblings on the geographic distance between adult children and their ageing parents. Does parental need matter?

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    Research consistently shows that children with siblings live at a greater distance from their parents than do only children. We extend this literature by assessing whether this difference varies as a function of parental need. Multinomial logistic regression analyses of German Ageing Survey data enriched with indicators at the district (NUTS3) level (n = 2,028) show that, in general, children with a sibling are less likely than only children to share a household with a parent. We do not find that children with a sibling are more likely than only children to live at great distance, i.e. more than two hours away, from their parents. The differences between only children and children with siblings in parent-child proximity are most pronounced when parents are coping with severe health limitations. It is well-established that only children are more likely than children with siblings to provide support and care to ageing parents. Our findings suggest that, in addition, only children might be more compelled than their counterparts with siblings to adjust their living arrangements in order to facilitate caregiving when parent care needs manifest themselves

    Measurement of the tt¯tt¯ production cross section in pp collisions at √s=13 TeV with the ATLAS detector

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    A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fb−1 is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain b-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be 26+17−15 fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be 24+7−6 fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12.0 ± 2.4 fb
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