The role of impulse parameters in force variability

One of the principle limitations of the human motor system is the ability to produce consistent motor responses. When asked to repeatedly make the same movement, performance outcomes are characterized by a considerable amount of variability. This occurs whether variability is expressed in terms of kinetics or kinematics. Variability in performance is of considerable importance because for tasks requiring accuracy it is a critical variable in determining the skill of the performer. What has long been sought is a description of the parameter or parameters that determine the degree of variability. Two general experimental protocals were used. One protocal is to use dynamic actions and record variability in kinematic parameters such as spatial or temporal error. A second strategy was to use isometric actions and record kinetic variables such as peak force produced. What might be the important force related factors affecting variability is examined and an experimental approach to examine the influence of each of these variables is provided

An Analysis of Kinetic Response Variability

Studies evaluating variability of force as a function of absolute force generated are synthesized. Inconsistencies in reported estimates of this relationship are viewed as a function of experimental constraints imposed. Typically, within-subject force variability increases at a negative accelerating rate with equal increments in force produced. Current pulse-step and impulse variability models are unable to accommodate this description, although the notion of efficiency is suggested as a useful construct to explain the description outlined

Effects of Urban Land Cover on Magnitude and Interannual Variability of Evapotranspiration

Quantifying actual evapotranspiration (AET) in urbanized watersheds helps water managers develop accurate water budgets and aids in predicting future water budgets, especially in the face of land-cover and climate change. This paper presents multiple methods, with focus on Penman-Monteith approach, to estimate 20 years of daily, monthly, and annual AET totals in an urbanized watershed, the South River watershed (SRW), in Atlanta, GA. Land cover analysis confirmed NLCD definitions and revealed developed classes 21-24 contain 48.18%, 24.26%, 13.79%, and 4.43% forest cover, respectively. Additionally, it was found that the annual AET of the SRW is approximately 800 mm/yr, with about 10% coming solely from impervious land cover. A decreasing annual AET trend was observed for the SRW, resulting from land cover changes and decreasing incoming solar radiation. Finally, TerraClimate reference AET datasets overestimated urban AET, while statistical models typically underestimated AET when compared to reference water balance AET estimates

An electronic weather vane for field science

This paper details the construction of a weather vane for the measurement of wind direction in field situations. The purpose of its construction was to analyse how wind direction affected the attractiveness of an insect pheromone in a dynamic outdoor environment, where wind could be a significant contributor to odour movement. The apparatus described provides a cheap and easy-to-construct alternative to commercial wind vanes, and was shown to provide accurate and continuous measurement of wind direction

The Gale Crater Mound in a Regional Geologic Setting

The Mars Science Laboratory Rover Curiosity is commencing a two-year investigation of Gale crater and Mt. Sharp, the crater s prominent central mound. Gale is a 155 km, late Noachian / early Hesperian impact crater located near the dichotomy boundary separating the southern highlands from the northern plains. The central mound is composed of layered sedimentary rock, with upper and lower mound units separated by a prominent erosional unconformity (Milliken et al., 2010). The lower mound is of particular interest, as it contains secondary minerals indicative of a striking shift from water-rich to water-poor conditions on early Mars. A key unknown in the history of Gale is the relationship between the sedimentary units in the mound and sedimentary sequences in the surrounding region. We employed orbital remote sensing data to determine if areas within a 1,000 km radius of Gale match the characteristics of sedimentary units in Mt. Sharp. Regions of interest were defined based on: the mound s inferred age (late Noachian to early Hesperian), altitude range (-4,600 m to +400 m), and THEMIS nighttime brightness (a proxy for thermal inertia). This combination of characteristics is matched by two extensive units, the late Noachian subdued cratered unit Npl2 and Noachian / Hesperian undivided material HNu (Greeley and Guest, 1987), located along the dichotomy. Geomorphic units have been mapped within the Gale mound by Thomson et al. (2011) based on albedo, layering and erosional characteristics. Using orbital CTX, MOC and HiRISE images we examined all areas within our regions of interest for analogous geomorphic units in the same altitude ranges as the corresponding units in Mt. Sharp. The most convincing geomorphic analogs to lower mound units, dominated by fine-scale layering and prominent yardangs, were located approximately 200 km northeast and southeast of Gale in late Noachian unit Npl2. The most convincing geomorphic analogs to upper mound layered units are located 250 900 km northwest of Gale in unit HNu, estimated to span the Noachian / Hesperian boundary

WFIRST Coronagraph Technology Requirements: Status Update and Systems Engineering Approach

The coronagraphic instrument (CGI) on the Wide-Field Infrared Survey Telescope (WFIRST) will demonstrate technologies and methods for high-contrast direct imaging and spectroscopy of exoplanet systems in reflected light, including polarimetry of circumstellar disks. The WFIRST management and CGI engineering and science investigation teams have developed requirements for the instrument, motivated by the objectives and technology development needs of potential future flagship exoplanet characterization missions such as the NASA Habitable Exoplanet Imaging Mission (HabEx) and the Large UV/Optical/IR Surveyor (LUVOIR). The requirements have been refined to support recommendations from the WFIRST Independent External Technical/Management/Cost Review (WIETR) that the WFIRST CGI be classified as a technology demonstration instrument instead of a science instrument. This paper provides a description of how the CGI requirements flow from the top of the overall WFIRST mission structure through the Level 2 requirements, where the focus here is on capturing the detailed context and rationales for the CGI Level 2 requirements. The WFIRST requirements flow starts with the top Program Level Requirements Appendix (PLRA), which contains both high-level mission objectives as well as the CGI-specific baseline technical and data requirements (BTR and BDR, respectively)... We also present the process and collaborative tools used in the L2 requirements development and management, including the collection and organization of science inputs, an open-source approach to managing the requirements database, and automating documentation. The tools created for the CGI L2 requirements have the potential to improve the design and planning of other projects, streamlining requirement management and maintenance. [Abstract Abbreviated]Comment: 16 pages, 4 figure

Inhibition of \u3cem\u3eRhizobium etli\u3c/em\u3e Polysaccharide Mutants by \u3cem\u3ePhaseolus vulgaris\u3c/em\u3e Root Compounds

Crude bean root extracts of Phaseolus vulgaris were tested for inhibition of the growth of several polysaccharide mutants of Rhizobium etli biovar phaseoli CE3. Mutants deficient only in exopolysaccharide and some mutants deficient only in the O-antigen of the lipopolysaccharide were no more sensitive than the wild-type strain to the extracts, whereas mutants defective in both lipopolysaccharide and exopolysaccharide were much more sensitive. The inhibitory activity was found at much higher levels in roots and nodules than in stems or leaves. Inoculation with either wild-type or polysaccharide-deficient R. etli did not appear to affect the level of activity. Sequential extractions of the crude root material with petroleum ether, ethyl acetate, methanol, and water partitioned inhibitory activity into each solvent except methanol. The major inhibitors in the petroleum ether and ethyl acetate extracts were purified by C18 high-performance liquid chromatography. These compounds all migrated very similarly in both liquid and thin-layer chromatography but were distinguished by their mass spectra. Absorbance spectra and fluorescence properties suggested that they were coumestans, one of which had the mass spectrum and nuclear magnetic resonances of coumestrol. These results are discussed with regard to the hypothesis that one role of rhizobial polysaccharides is to protect against plant toxins encountered during nodule development

Examining the economic impact of transport complex economies

Transport complex economies (TCEs), which comprise both upstream and downstream firms in the transport chain that conduct shipping and trade-related activities, can be desirable locations for port users (e.g., traders, logistics service providers, shipping lines and terminal operators) to perform their business activities. To explore TCEs, this study identifies trade facilitation measures at both the macro and micro levels to enhance regional performance. Hypotheses have been developed to build a theoretical model to illustrate the relationship between trade facilitation activities and trade costs. The economic outcomes are also examined in the theoretical model. To validate the proposed model, we have collected data from the World Bank and employed structural equation modelling. The result suggests that trade facilitation measures are negatively associated with trade cost. The result also suggests that the trade facilitation measures of a region is positively associated with its economic performance. Based on the findings, users can formulate effective and efficient strategies to select a location for their firm to conduct business activities. The findings illustrate the importance of the development of social capital for trade facilitation from the perspective of policy makers

Beyond Triage: The Diagnostic Accuracy of Emergency Department Nursing Staff Risk Assessment in Patients with Suspected Acute Coronary Syndromes.

Objectives To establish the accuracy of emergency department (ED) nursing staff risk assessment using an established chest pain risk score alone and when incorporated with presentation high-sensitivity troponin testing as part of an accelerated diagnostic protocol (ADP). Design Prospective observational study comparing nursing and physician risk assessment using the modified Goldman (m-Goldman) score and a predefined ADP, incorporating presentation high-sensitivity troponin. Setting A UK District ED. Patients Consecutive patients, aged 7ge;18, with suspected cardiac chest pain and non-ischaemic ECG, for whom the treating physician determined serial troponin testing was required. Outcome measures 30-day major adverse cardiac events (MACE). Results 960 participants were recruited. 912/960 (95.0%) had m-Goldman scores recorded by physicians and 745/960 (77.6%) by nursing staff. The area under the curve of the m-Goldman score in predicting 30-day MACE was 0.647 (95% CI 0.594 to 0.700) for physicians and 0.572 (95% CI 0.510 to 0.634) for nursing staff ( p=0.09). When incorporated into an ADP, sensitivity for the rule-out of MACE was 99.2% (95% CI 94.8% to 100%) and 96.7% (90.3% to 99.2%) for physicians and nurses, respectively. One patient in the physician group (0.3%) and three patients (1.1%) in the nursing group were classified as low risk yet had MACE. There was fair agreement in the identification of low-risk patients (kappa 0.31, 95% CI 0.24 to 0.38). Conclusions The diagnostic accuracy of ED nursing staff risk assessment is similar to that of ED physicians and interobserver reliability between assessor groups is fair. When incorporating high-sensitivity troponin testing, a nurse-led ADP has a miss rate of 1.1% for MACE at 30 days. Trial registration number Controlled Trials Database (ISRCTN no. 21109279)

Reproducibility of limb power outputs and cardiopulmonary responses to exercise using a novel swimming training machine

The purpose of this study was to determine the reproducibility of limb power output and cardiopulmonary responses, to incremental whole-body exercise using a novel swimming training machine. Eight swimmers with a mean age of 23.7 ± 4.6 (yrs), stature 1.77 ± 0.13 (m) and body mass of 74.7 ± 2.8 (kg) gave informed consent and participated in repeat exercise testing on the machine. All subjects performed two incremental exercise tests to exhaustion using front crawl movements. From these tests peak oxygen consumption (VO2peak), peak heart rate (HRpeak), peak power output (Wpeak) and individual limb power outputs were determined. Results showed there were no significant differences between test 1 and 2 for any variable at exhaustion, and the CV% ranged from 2.8% to 3.4%. The pooled mean values were; VO2peak 3.7 ± 0.65 L.min-1, HRpeak 178.7 ± 6.6 b.min-1 and Wpeak 349.7 ± 16.5 W. The mean contributions to the total power output from the legs and arms were (37.3 ± 4.1 % and 62.7 ± 5.1 % respectively). These results show that it is possible to measure individual limb power outputs and cardopulmonary parameters reproducibly during whole-body exercise using this training machine, at a range of exercise intensitie