Metal matrix composite analyzer (METCAN) user's manual, version 4.0

The Metal Matrix Composite Analyzer (METCAN) is a computer code developed at Lewis Research Center to simulate the high temperature nonlinear behavior of metal matrix composites. An updated version of the METCAN User's Manual is presented. The manual provides the user with a step by step outline of the procedure necessary to run METCAN. The preparation of the input file is demonstrated, and the output files are explained. The sample problems are presented to highlight various features of METCAN. An overview of the geometric conventions, micromechanical unit cell, and the nonlinear constitutive relationships is also provided

On The Nature of Variations in the Measured Star Formation Efficiency of Molecular Clouds

Measurements of the star formation efficiency (SFE) of giant molecular clouds (GMCs) in the Milky Way generally show a large scatter, which could be intrinsic or observational. We use magnetohydrodynamic simulations of GMCs (including feedback) to forward-model the relationship between the true GMC SFE and observational proxies. We show that individual GMCs trace broad ranges of observed SFE throughout collapse, star formation, and disruption. Low measured SFEs (<<1%) are "real" but correspond to early stages, the true "per-freefall" SFE where most stars actually form can be much larger. Very high (>>10%) values are often artificially enhanced by rapid gas dispersal. Simulations including stellar feedback reproduce observed GMC-scale SFEs, but simulations without feedback produce 20x larger SFEs. Radiative feedback dominates among mechanisms simulated. An anticorrelation of SFE with cloud mass is shown to be an observational artifact. We also explore individual dense "clumps" within GMCs and show that (with feedback) their bulk properties agree well with observations. Predicted SFEs within the dense clumps are ~2x larger than observed, possibly indicating physics other than feedback from massive (main sequence) stars is needed to regulate their collapse.Comment: Fixed typo in the arXiv abstrac

The Effects of Chronic Pain Levels on Lower Extremity Energetics During Jump Landing/Cutting in Chronic Ankle Instability Patients

Up to 75% of patients with lateral ankle sprains develop chronic ankle instability (CAI). A majority of CAI patients report chronic pain and show altered jump landing/cutting patterns. Calculating joint energetics affected by chronic pain provides insight into understanding the effects of chronic pain levels on lower limbs in CAI patients. PURPOSE: To identify the effects of chronic pain levels on lower limb energetics during jump landing/cutting in CAI patients. METHODS: This study was a cross-sectional study. Fifteen CAI patients with high pain (High pain) (6males, 9females; age=22.1±2.1year; height=1.74±0.09m; mass=71.3±10.6kg, pain=66.9±9.4), matched 15 CAI patients with low pain (Low pain) (6males, 9females; age=22.3±2.1year; height=1.74±0.08m; mass=70.1±10.7kg, pain=89.3±2.6), and matched 15 healthy controls (Control) (6males, 9females; age=21.3±1.7year; height=1.73±0.08m; mass=70±10.3kg, pain=100±0). We followed the International Ankle Consortium and utilized the Foot and Ankle Outcome Scores for CAI and chronic pain levels. Ground reaction forces were collected during the jump landing/cutting, while joint power was defined by angular velocity and joint moment data. We calculated ankle, knee, and hip joint energy via the integration of negative (dissipation) or positive (generation) power curve areas. The loading phase was defined by the time from initial contact to 150 ms following, while the cutting phase extended from maximal knee flexion to 150 ms following. The Wilcoxon signed-rank test was used to assess joint energetics data. RESULTS: The high pain showed less energy dissipation and generation in the ankle during the loading and cutting phase than the low pain (p=.013 and p=.002) and control (p=.018 and p=.028). The high pain exhibited more energy generation in the hip during the cutting phase than the low pain (p=.038) and control (p=.013). CONCLUSION: The high pain showed lower energy dissipation and generation in the ankle during the loading and cutting phase than the low pain and control, possibly reflecting an effort to reduce the burden on the ankle joint. The high pain reported more energy generation in the hip during the cutting phase than the low pain and control, suggesting a proximal compensatory strategy. Therefore, chronic pain may impact motor outcomes

Farmer intentional pathways for net zero carbon: exploring the lock-in effects of forestry and renewables

Climate smart farming requires food production to sit alongside practices which sequester greenhouse gas emissions. Given the requirement to meet net zero emissions by the middle of the century, agricultural policies are now seeking to embed climate smart approaches within future support schemes. Path dependency, the influence of past choices on decision making, has been found to constrain future growth pathways. We apply this concept within a survey of 2494 farmers in Scotland to understand their intentions towards uptake of two prominent climate smart approaches, namely forestry expansion and on-farm renewable energy. We employ a bivariate probit model to estimate the single and joint dependences of these two activities within a farm decision making framework. Factors such as succession planning, the level of agricultural diversification and risk seeking perceptions were found to be positively related to influencing uptake. However, the strongest predictors for uptake were past expansion of these activities and, conversely, a limiting factor for those who did not intend to increase activities. This provides some evidence that path dependencies will limit large scale adoption to meet a net zero target. We argue for a dual approach to intervention which differentiates between past adopters and those who are reluctant to adopt. More targetted support for these two cohorts would address these high level policy ambitions.</p

Examining the Acute Effects of Virtual Reality on the Star Excursion Balance Test in Chronic Ankle Instability

Chronic ankle instability (CAI) patients display mechanical and functional restrictions, along with neurocognitive dysfunction after lateral ankle sprains. Athletes need to divide their attention to effectively multitask during sports activities. Recent studies have utilized virtual reality (VR) to simulate dynamic sporting environments, aiming to enhance cognitive and postural control. However, little is known about the acute effects of VR on dynamic postural control in CAI patients. PURPOSE: To identify the acute effects of VR gear on dynamic postural control in CAI patients. METHODS: This study was a cross-over study. Twenty CAI patients (11males, 9females; age=21±3year; height=1.63±0.28m; mass=74±13.1kg). We used the Foot and Ankle Ability Measures and Ankle Instability Instrument questionnaires for CAI. VR training included 3 trials of single-leg stance; double and single-leg drop landings; and 5 trials of jump landing/cutting. Before and after VR training, participants performed 3 trials each in 3 directions: anterior (ANT), posteromedial (PM), and posterolateral (PL). The average reach distance was normalized by an individual’s leg length from the anterior superior iliac spine to the distal end of the medial malleolus. Matched paired t-tests were used to evaluate the acute effect (posttest-pretest difference) of VR training. The significance level for all analyses was set at a priori of p≤0.05. RESULTS: Acute effects were not observed in both ANT and PM directions (60.2±7.2 vs. 60.9±6.9, p=0.15 and 103.3±10.4 vs. 104.6±11.2, p=0.31). CAI patients showed an acute effect, improving PL reach distance (98.3±11.2 vs. 102.1±13.3, p=0.006) during the star excursion balance test after VR training. CONCLUSION: VR resulted in no difference in ANT direction, which is related to the dorsiflexion range of motion, suggesting that VR training had no improvement in mechanical restriction. After VR training, PL reach distance was increased, suggesting improvement in functional restriction in CAI patients. Therefore, VR training may affect functional restriction, by potentially increasing eversion strength and improving mediolateral static postural control. More data are needed to determine if VR may reduce the risk of recurrent ankle sprains in CAI patients

Effects of Anticipation on Energy Dissipation Patterns among Chronic Ankle Instability Patients

Ankle inversion injuries often lead to chronic ankle instability (CAI). CAI patients use altered energy dissipation patterns during jump-landing, but most studies have been limited to tasks performed under anticipated conditions. It is unclear how the anticipatory condition affects joint energetics in CAI patients. PURPOSE: To identify the effects of anticipation on energy dissipation during jump-landing among CAI, coper, and control subjects. METHODS: 60 subjects were categorized according to the Foot and Ankle Ability Measure and Ankle Instability Index. 20 CAI patients (10males, 10females, 1.74±0.1m, 69.1±10.2kg), 20 Copers (10males, 10females, 1.76±0.1m, 70.9±11.1kg), and 20 Controls (10males, 10females, 1.74±0.1m, 66.0±10.7kg) participated. Participants completed 3 trials of maximal jump-landing tasks (via arrows shown on a screen) performed under anticipated/unanticipated conditions. Energy dissipation by the ankle, knee, and hip joints was calculated by integrating regions of the joint power curve during the task. Lower extremity joint energy dissipation was calculated for the hip, knee, and ankle in the sagittal plane during 50, 100, 150, and 200 ms after initial contact with the force plate. Two-way repeated measures ANOVAs (group × condition) were used to examine the differences between condition (Anticipated, Unanticipated) and group (CAI, coper, control). RESULTS: In the unanticipated condition, copers displayed reduced ankle/hip energy dissipation and increased knee energy dissipation compared to the anticipated condition, while the CAI and Control groups demonstrated no change in energy dissipation between the two conditions. CONCLUSION: CAI patients were unable to change energy dissipation patterns between the two conditions. This finding may represent an apprehension for extra ankle strain compared to the copers. In the earliest stages of jump-landing, copers displayed the most altered energy dissipation patterns, shifting from heavily favoring the ankle during anticipated movement to dissipating much more energy into the knee while reducing the load on the ankle. These energy patterns may indicate a coping mechanism and increased knee energy dissipation in copers may be an effort to attenuate load during landing as a strategy to lessen the load absorbed by the ankle

The Effects of Chronic Pain Levels on Lower Extremity Muscle Activation During Jump Landing/Cutting in Individuals with Chronic Ankle Instability

Lateral ankle sprains (LASs) are the most common injury in sports. Up to 74% of individuals with an initial LAS develop chronic ankle instability (CAI) with chronic ankle pain being one of the residual symptoms. PURPOSE: To Identify the effects of chronic pain levels on lower extremity muscle activation during a maximal jump landing/cutting in CAI individuals. METHODS: This study was a cross-sectional study. Twenty CAI individuals with high pain (High pain) (9M, 11F; age=22±2year; height= 1.74±0.10m; mass=79.4±14.6kg, pain=67.4±7.7), 20 CAI individuals with low pain (Low pain) (9M, 11F; age=21±3year; height=1.73±0.08m; mass=74.2±12.7kg, pain=91.7±3.9), and 20 healthy controls (Control) (9M, 11F; age=22±1year; height=1.74±0.09m; mass=68.2±10.2kg, pain=100±0). We followed the International Ankle Consortium and Foot and Ankle Outcome Scores for classification of CAI and chronic pain. Electromyography (EMG) data were collected using wireless surface electrodes (2,000 Hz) during 5 trials of maximal jump landing/cutting from initial contact to toe-off (0-100% of stance). Reference EMG data were collected standing position for 3 seconds. EMG data were normalized to the reference EMG data. The electrodes were placed over the tibialis anterior (TA), peroneus longus (PL), medial gastrocnemius (MG), vastus lateralis (VL), gluteus medius (Gmed), and gluteus maximus (Gmax). Functional analyses of variance were used to evaluate between-group differences for kinematics outcomes. RESULTS: The high pain showed 3.3%, 16%, and 14% less activation in TA, PL, and MG, and 16% and 14% more activation in the VL and Gmed than the low pain. The high pain displayed 26%, 11.1%, 15%, 8.2%, 25.4%, and 11.5% less activation in the TA, PL, MG, VL, Gmed, and Gmax than the control. The low pain showed 14.9%, 18.7%, and 11.2% less activation in the TA, VL, and Gmed, and 8.7% more activation in the PL during the landing/cutting than the control. CONCLUSION: Chronic pain levels appear to impact muscle activation in CAI individuals. Both the high and low pain demonstrate altered muscle activation patterns in distal and proximal joints. The high pain prompts a hip-dominant strategy, compensating for deactivated distal muscles. The lower the level of chronic pain, the more active the PL muscles that contribute to ankle stability

The Effects of Chronic Pain Levels on Joint Angle During Jump Landing/Cutting in Individuals with Chronic Ankle Instability

About 60% of chronic ankle instability (CAI) individuals report ankle pain persisting for longer than 3 months. They have the risk of recurrent ankle sprains while performing multiplanar tasks such as jumping with landing/cutting. However, little is known about the effects of chronic pain levels on joint kinematics differences and how chronic pain levels contribute to motor outcomes when performing multiplanar motions. PURPOSE: To identify the effects of pain levels on kinematics during jump landing/cutting in CAI individuals. METHODS: This study was a cross-sectional study. Twenty CAI patients with high pain (high pain) (9 males, 11 females; age=22±2year; height=1.74±0.10m; mass=79.4±14.6kg, pain=67.4±7.7), 20 CAI patients with low pain (low pain) (9 males, 11 females; age=21±3year; height=1.73±0.08m; mass=74.2±12.7kg, pain=91.7±3.9), and 20 healthy controls (9 males, 11 females; age=22±1year; height=1.74±0.09m; mass=68.2±10.2kg, pain=100±0). We followed the International Ankle Consortium criteria for classifying CAI and utilized the Foot and Ankle Outcome Scores for chronic pain levels. We used 44 reflective markers to calculate joint angles collected during the jump landing/cutting task from initial contact to toe-off (0-100% of stance). Functional analyses of variance were used to evaluate between-group differences for kinematics outcomes. RESULTS: The high pain showed 4.8° less plantarflexion from 0-12% than the low pain from 0-8% and 4.9° less plantarflexion than the healthy control. The high pain exhibited 1.4° less inversion from 8-12% than the low pain. The knee joint presented 1.5° less flexion from 0-5% and then 4.4° more flexion at 10-24% than healthy controls, showing a greater knee joint angle variability. The high pain showed 5.3°, 3.6°, and 3.5° higher hip flexion from 2-24%, 50-61%, and 75-82%, respectively than the healthy control. CONCLUSION: The high pain demonstrated less plantarflexion and inversion in the ankle while exhibiting more kinematics variance in the knee joint and hip during multiplanar tasks. These findings may result in a stiffer landing in the ankle and proximal landing strategy during jump landing/cutting tasks. Thus, chronic pain levels affect joint kinematics during multiplanar tasks

Caspase-1 cleavage of the TLR adaptor TRIF inhibits autophagy and β-interferon production during pseudomonas aeruginosa infection

Bacterial infection can trigger autophagy and inflammasome activation, but the effects of inflammasome activation on autophagy are unknown. We examined this in the context of Pseudomonas aeruginosa macrophage infection, which triggers NLRC4 inflammasome activation. P. aeruginosa induced autophagy via TLR4 and its adaptor TRIF. NLRC4 and caspase-1 activation following infection attenuated autophagy. Caspase-1 directly cleaved TRIF to diminish TRIF-mediated signaling, resulting in inhibition of autophagy and in reduced type I interferon production. Expression of a caspase-1 resistant TRIF mutant enhanced autophagy and type I interferon production following infection. Preventing TRIF cleavage by caspase-1 in an in vivo model of P. aeruginosa infection resulted in enhanced bacterial autophagy, attenuated IL-1β production, and increased bacterial clearance. Additionally, TRIF cleavage by caspase-1 diminished NLRP3 inflammasome activation. Thus, caspase-1 mediated TRIF cleavage is a key event in controlling autophagy, type I interferon production, and inflammasome activation with important functional consequences

Lipid biomarker and stable isotopic profiles through Early-Middle Ordovician carbonates from Spitsbergen, Norway

One of the most dramatic episodes of sustained diversification of marine ecosystems in Earth history took place during the Early to Middle Ordovician Period. Changes in climate, oceanographic conditions, and trophic structure are hypothesised to have been major drivers of these biotic events, but relatively little is known about the composition and stability of marine microbial communities controlling biogeochemical cycles at the base of the food chain. This study examines well-preserved, carbonate-rich strata spanning the Tremadocian through Upper Dapingian stages from the Oslobreen Group in Spitsbergen, Norway. Abundant bacterial lipid markers (elevated hopane/sterane ratios, average = 4.8; maximum of 13.1), detection of Chlorobi markers in organic-rich strata, and bulk nitrogen isotopes (delta N-15(total)) averaging 0 to -1 parts per thousand for the open marine facies, suggest episodes of water column redox-stratification and that primary production was likely limited by fixed nitrogen availability in the photic zone. Near absence of the C-30 sterane marine algal biomarker, 24-n-propylcholestane (24-npc), in most samples supports and extends the previously observed hiatus of 24-npc in Early Paleozoic (Late Cambrian to Early Silurian) marine environments. Very high abundances of 3 beta-methylhopanes (average = 9.9%; maximum of 16.8%), extends this biomarker characteristic to Early Ordovician strata for the first time and may reflect enhanced and sustained marine methane cycling during this interval of fluctuating climatic and low sulfate marine conditions. Olenid trilobite fossils are prominent in strata deposited during an interval of marine transgression with biomarker evidence for episodic euxinia/anoxia extending into the photic zone of the water column. (C) 2019 Elsevier Ltd. All rights reserved.Peer reviewe