199 research outputs found

    Applying a Mt. Mazama Volcanic Ash Treatment as a Trail Accessibility Improvement

    Get PDF
    A procedure has been developed for implementing a topically applied Mt. Mazama volcanic ash trail surface amendment for improving trail firmness and stability. This project involved implementation of previously conducted Mt. Mazama volcanic research by applying a Mazama Ash and Portland Cement solution over a 0.2-mile section of the Geo Trail at the Oregon Institute of Technology Klamath Falls campus. Testing was performed to verify ideal Ash-to-Cement-to-Water ratios. A procedure was developed and applied for batching and mixing the dry materials on-site, spreading and integrating the dry material with the existing trail surface, and wetting and compacting the surface. After the pilot application, visual inconsistencies were observed in the treated trail surface. Firmness and stability were measured at different locations along the treated trail surface and on the untreated surface with a rotational penetrometer apparatus. Roughness was quantified using a modified Wheelchair Pathway Roughness Index at different locations along the treated rail surface and on the untreated surface. At each of the testing locations on the treated surface, stability was shown to have improved, firmness was relatively consistent, and the ability to roll an occupied wheelchair without rutting was markedly improved

    The Scaled Arrival of K-12 Online Education: Emerging Realities and Implications for the Future of Education

    Get PDF
    Bioinfo PublicationsDramatic increases in K—12 online education for all students, including those in traditionally underserved populations, necessi2 tate a reconceptualization in the way educators plan and implement instruction. In this article the authors examine the complex array of variables and implementation models that must be accounted for during the pivot from a purely brick-and-mortar educational sys2 tem to one that makes use of both virtual and blended environ2 ments. The authors call for enhanced emphasis on instructional goals and design principles, rather than the capabilities of available technology. They conclude that educational leaders and researchers must play a role in three key areas: using technology to enhance the accessibility and usability of curricular materials to meet the needs of different types of learners, advancing the understanding and practices of in-service and pre-service teachers through preparation that focuses on online learning, and fostering collaboration between educational researchers and technology innovators and developers to build a research base that will inform K—12 online education

    EFFECTS OF KAATSU TRAINING ON UPPER EXTREMITY SIZE AND STRENGTH

    Get PDF
    poster abstractConventional resistance training involves lifting heavy loads (~70% max-imal strength), which can be poorly tolerated or contraindicated in many clinical populations. KAATSU training is a novel training mode from Japan that combines muscle blood flow restriction with low load lifting (~20% max-imal strength). The purpose of this study was to investigate the effects of a KAATSU training program on upper extremity size and strength. Forty healthy subjects ages 18 to 30 were divided into exercise (EX) or control (CON) groups. Subjects reported to the laboratory three times per week for eight weeks. The EX group performed 3 sets of 15 repetitions of unilateral bicep curls and triceps extensions lifting loads equivalent to 20% of their predetermined maximal strength while wearing a pneumatic cuff to restrict blood flow on one arm (CUFF) and nothing on the other (NCUFF). The CON group did not perform any exercises but wore the cuff on one arm for a time comparable to the EX group. CUFF and NCUFF arms were randomly as-signed. Strength, girth, skin folds and tomography scans were taken pre-, during, and post-eight weeks. In the EX group, bicep curl (17.4% +4.1% and 18.7% +4.9%) and triceps extension (15.8% +3.4% and 10.7% +2.7%) strength increased significantly over the 8-week period for both the CUFF and NCUFF arms, respectively. No significant differences in strength occurred between the CUFF and NCUFF arms within the group. No strength changes were noted in the CON group for the CUFF and NCUFF arms. Arm girth and muscle cross-sectional area (mCSA) increased significantly in the EX subjects compared to the CON subjects, however no significant differ-ences were found when within group comparisons were made between the CUFF and NCUFF arms. This study indicates that KAATSU training can in-crease muscle strength and mCSA

    KAATSU TRAINING: PERCEPTIONS AND COMPLIANCE TO AN UPPER ARM EXERCISE PROGRAM

    Get PDF
    poster abstractKAATSU training is a novel Japanese training mode involving low load (~20% maximal strength) weightlifting combined with blood flow restriction to the muscles. Little is known about the sensations experienced during KAATSU training and whether clients will tolerate it. The purpose of this study was to assess perceived sensations, exertion rates, and compliance to an upper arm KAATSU training program. Forty healthy subjects ages 18 to 30 were divided into exercise (EX) or control (CON) groups. Subjects report-ed to the laboratory three times per week for eight weeks. The EX group performed 3 sets of 15 repetitions of unilateral bicep curls and triceps exten-sions lifting loads equivalent to 20% of their predetermined maximal strength while wearing a pneumatic cuff on one arm (CUFF) and nothing on the other (NCUFF). The CON group did not perform any exercises but wore the cuff on one arm for a time comparable to the EX group. CUFF and NCUFF arms were randomly assigned. Sensations (burning, aching, pressure, pins & needles) and perceived exertion were assessed using visual analog scales that included emotions and verbal cues. Compliance (percentage of subjects completing the pre- and post-testing) and adherence (percentage of ses-sions completed) were tracked to provide an indication of training tolerance. Compliance was 85.4% and 97% for the EX and CON groups, respectively. EX subjects completed 85.4% of their workouts while controls attended 90.4% of their sessions. The prominent sensation reported in the CUFF arm was pressure (moderate; 3.2 +0.6) followed by aching (weak; 1.7 +0.4). Ratings of perceived exertion were higher for the CUFF (3.2 +1.0, 5.1 +1.8, and 7.0 +2.5) versus NCUFF (1.5 +0.3, 2.4 +0.3, and 3.3 +0.4) arm for sets 1, 2, and 3, respectively. KAATSU training is well tolerated by those performing it and a viable alternative to conventional resistance exercise

    LAT1 Protein Content Increases Following 12 Weeks of Resistance Exercise Training in Human Skeletal Muscle

    Get PDF
    Introduction: Amino acid transporters are essential for cellular amino acid transport and promoting protein synthesis. While previous literature has demonstrated the association of amino acid transporters and protein synthesis following acute resistance exercise and amino acid supplementation, the chronic effect of resistance exercise and supplementation on amino acid transporters is unknown. The purpose herein was to determine if amino acid transporters and amino acid metabolic enzymes were related to skeletal muscle hypertrophy following resistance exercise training with different nutritional supplementation strategies. Methods: 43 college-aged males were separated into a maltodextrin placebo (PLA, n = 12), leucine (LEU, n = 14), or whey protein concentrate (WPC, n = 17) group and underwent 12 weeks of total-body resistance exercise training. Each group\u27s supplement was standardized for total energy and fat, and LEU and WPC supplements were standardized for total leucine (6 g/d). Skeletal muscle biopsies were obtained prior to training and ~72 h following each subject\u27s last training session. Results: All groups increased type I and II fiber cross-sectional area (fCSA) following training (p \u3c 0.050). LAT1 protein increased following training (p \u3c 0.001) and increased more in PLA than LEU and WPC (p \u3c 0.050). BCKDHα protein increased and ATF4 protein decreased following training (p \u3c 0.001). Immunohistochemistry indicated total LAT1/fiber, but not membrane LAT1/fiber, increased with training (p = 0.003). Utilizing all groups, the change in ATF4 protein, but no other marker, trended to correlate with the change in fCSA (r = 0.314; p = 0.055); however, when regression analysis was used to delineate groups, the change in ATF4 protein best predicted the change in fCSA only in LEU (r2 = 0.322; p = 0.043). In C2C12 myoblasts, LAT1 protein overexpression caused a paradoxical decrease in protein synthesis levels (p = 0.002) and decrease in BCKDHα protein (p = 0.001). Conclusions: Amino acid transporters and metabolic enzymes are affected by resistance exercise training, but do not appear to dictate muscle fiber hypertrophy. In fact, overexpression of LAT1 in vitro decreased protein synthesis

    Deformation of Crystals: Connections with Statistical Physics

    Get PDF
    We give a bird's-eye view of the plastic deformation of crystals aimed at the statistical physics community, as well as a broad introduction to the statistical theories of forced rigid systems aimed at the plasticity community. Memory effects in magnets, spin glasses, charge density waves, and dilute colloidal suspensions are discussed in relation to the onset of plastic yielding in crystals. Dislocation avalanches and complex dislocation tangles are discussed via a brief introduction to the renormalization group and scaling. Analogies to emergent scale invariance in fracture, jamming, coarsening, and a variety of depinning transitions are explored. Dislocation dynamics in crystals challenge nonequilibrium statistical physics. Statistical physics provides both cautionary tales of subtle memory effects in nonequilibrium systems and systematic tools designed to address complex scale-invariant behavior on multiple length scales and timescales

    Observations of High-Redshift X-Ray Selected Clusters with the Sunyaev-Zel'dovich Array

    Get PDF
    We report measurements of the Sunyaev-Zel'dovich (SZ) effect in three high-redshift (0.89 ≤ z ≤ 1.03), X-ray selected galaxy clusters. The observations were obtained at 30 GHz during the commissioning period of a new, eight-element interferometer—the Sunyaev-Zel'dovich Array (SZA)—built for dedicated SZ effect observations. The SZA observations are sensitive to angular scales larger than those subtended by the virial radii of the clusters. Assuming isothermality and hydrostatic equilibrium for the intracluster medium and gas-mass fractions consistent with those for clusters at moderate redshift, we calculate electron temperatures, gas masses, and total cluster masses from the SZ data. The SZ-derived masses, integrated approximately to the virial radii, are 1.9^(+0.5)_(-0.4) × 10^(14) M_☉ for Cl J1415.1+3612, 3.4^(+0.6)_(-0.5) × 10^(14) M_☉ for Cl J1429.0+4241, and 7.2^(+1.3)_(-0.9) × 10^(14) M_☉ for Cl J1226.9+3332. The SZ-derived quantities are in good agreement with the cluster properties derived from X-ray measurements

    Sunyaev Zel'dovich Effect Observations of Strong Lensing Galaxy Clusters: Probing the Over-Concentration Problem

    Get PDF
    We have measured the Sunyaev Zel'dovich (SZ) effect for a sample of ten strong lensing selected galaxy clusters using the Sunyaev Zel'dovich Array (SZA). The SZA is sensitive to structures on spatial scales of a few arcminutes, while the strong lensing mass modeling constrains the mass at small scales (typically < 30"). Combining the two provides information about the projected concentrations of the strong lensing clusters. The Einstein radii we measure are twice as large as expected given the masses inferred from SZ scaling relations. A Monte Carlo simulation indicates that a sample randomly drawn from the expected distribution would have a larger median Einstein radius than the observed clusters about 3% of the time. The implied overconcentration has been noted in previous studies with smaller samples of lensing clusters. It persists for this sample, with the caveat that this could result from a systematic effect such as if the gas fractions of the strong lensing clusters are substantially below what is expected.Comment: submitte

    A Minimal Model of Metabolism Based Chemotaxis

    Get PDF
    Since the pioneering work by Julius Adler in the 1960's, bacterial chemotaxis has been predominantly studied as metabolism-independent. All available simulation models of bacterial chemotaxis endorse this assumption. Recent studies have shown, however, that many metabolism-dependent chemotactic patterns occur in bacteria. We hereby present the simplest artificial protocell model capable of performing metabolism-based chemotaxis. The model serves as a proof of concept to show how even the simplest metabolism can sustain chemotactic patterns of varying sophistication. It also reproduces a set of phenomena that have recently attracted attention on bacterial chemotaxis and provides insights about alternative mechanisms that could instantiate them. We conclude that relaxing the metabolism-independent assumption provides important theoretical advances, forces us to rethink some established pre-conceptions and may help us better understand unexplored and poorly understood aspects of bacterial chemotaxis
    • …
    corecore