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Search Results: 1 - 10 of 137812 matches for " Stephen T. Smith "
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2018 Railroad Tie Survey  [PDF]
Stephen T. Smith
Journal of Transportation Technologies (JTTs) , 2019, DOI: 10.4236/jtts.2019.93017
Abstract: This article reports results of a survey of railroad tie management conducted by the Association of American Railroads (AAR) reflecting 2017 practices. Similar surveys were previously conducted for 2013 and 2008 practices. North American railroads purchase approximately 23 million new wood crossties annually. Most ties are used to replace worn ties. Through this survey, the AAR seeks to provide clarity to its member railroads, the regulators, and other interested parties, regarding how the railroads’ tie purchase preferences and used tie management choices have been changing in response to changing technologies and regulations. Technology changes include use of borate preservatives to dual-treat wood ties to provide longer service life in high decay environments, non-wood ties made of concrete or plastic, and energy conversion methods for used ties such as gasification and torrefaction. Passage of the EPA Non-Hazardous Secondary Materials (NHSM) rule in 2011, including updates in 2013, 2016, and 2018, is reducing the potential for recycling used ties as fuel. However, the EPA is also promoting use of biological materials, such as wood, to produce energy without increasing carbon dioxide (CO2) levels in the atmosphere, thus reducing human caused climate change. Purchase and tie management trends are indicated by the survey results. Approximately 95% of all ties purchased are preservative-treated wood. Due to demonstrated longer service life in high decay zones for wood ties that are dual treated with borate and either creosote or copper naphthenate, the fraction of concrete and plastic tie purchases has decreased while the faction of dual treated wood tie purchases has increased. Recycling used ties for energy remains the most common practice, at 66% of ties, but has declined from 81% in 2013. Reuse of ties for other treated wood uses, such as landscape and agricultural type purposes, remains common at approximately 18%. Landfill disposal remains uncommon, but seems to be increasing at 6% of removed ties. The shift away from recycling for energy is thought to result from the both impact of the EPA NHSM rule and the low cost of natural gas. The smaller market tie users, mainly the short line railroads in contrast to the Class 1 railroads, manage far fewer ties per company, but purchase and manage approximately 31% of all ties. The short lines recycle to landscape and agricultural uses at about half the rate of the Class 1s and dispose in landfills at a much higher rate of 76% versus 1.2% for the Class 1s. This difference is thought to result
Life Cycle Assessment of CCA-Treated Wood Highway Guard Rail Posts in the US with Comparisons to Galvanized Steel Guard Rail Posts  [PDF]
Christopher A. Bolin, Stephen T. Smith
Journal of Transportation Technologies (JTTs) , 2013, DOI: 10.4236/jtts.2013.31007

A cradle-to-grave life cycle assessment is done to identify the environmental impacts of chromated copper arsenate (CCA)-treated timber used for highway guard rail posts, to understand the processes that contribute to the total impacts, and to determine how the impacts compare to the primary alternative product, galvanized steel posts. Guard rail posts are the supporting structures for highway guard rails. Transportation engineers, as well as public and regulatory interests, have increasing need to understand the environmental implications of guard rail post selection, in addition to factors such as costs and service performance. This study uses a life cycle inventory (LCI) to catalogue the input and output data from guard rail post manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to assess anthropogenic and net greenhouse gas (GHG), acidification, smog, ecotoxicity, and eutrophication potentially resulting from life cycle air emissions. Other indicators of interest also are tracked, such as fossil fuel and water use. Comparisons of guard rail post products are made at a functional unit of one post per year of service. This life cycle assessment (LCA) finds that the manufacture, use, and disposition of CCA-treated wood guard rails offers lower fossil fuel use and lower anthropogenic and net GHG emissions, acidification, smog potential, and ecotoxicity environmental impacts than impact indicator values for galvanized steel posts. Water use and eutrophication impact indicator values for CCA-treated guard rail posts are greater than impact indicator values for galvanized steel guard rail posts.

Life Cycle Assessment of Creosote-Treated Wooden Railroad Crossties in the US with Comparisons to Concrete and Plastic Composite Railroad Crossties  [PDF]
Christopher A. Bolin, Stephen T. Smith
Journal of Transportation Technologies (JTTs) , 2013, DOI: 10.4236/jtts.2013.32015

Creosote-treated wooden railroad crossties have been used for more than a century to support steel rails and to transfer load from the rails to the underlying ballast while keeping the rails at the correct gauge. As transportation engineers look for improved service life and environmental performance in railway systems, alternatives to the creosote-treated wooden crosstie are being considered. This paper compares the cradle-to-grave environmental life cycle assessment (LCA) results of creosote-treated wooden railroad crossties with the primary alternative products: concrete and plastic composite (P/C) crossties. This LCA includes a life cycle inventory (LCI) to catalogue the input and output data from crosstie manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to evaluate greenhouse gas (GHG) emissions, fossil fuel and water use, and emissions with the potential to cause acidification, smog, ecotoxicity, and eutrophication. Comparisons of the products are made at a functional unit of 1.61 kilometers (1.0 mile) of rail-road track per year. This LCA finds that the manufacture, use, and disposition of creosote-treated wooden railroad crossties offers lower fossil fuel and water use and lesser environmental impacts than competing products manufactured of concrete and P/C.

Unbiased Estimators for Entropy and Class Number
Stephen Montgomery-Smith,T. Schürmann
Statistics , 2014,
Abstract: We introduce unbiased estimators for the Shannon entropy and the class number, in the situation that we are able to take sequences of independent samples of arbitrary length.
Small-scale structure in the interstellar medium: time-varying interstellar absorption towards κ Velorum
Keith T. Smith,Stephen J. Fossey,Martin A. Cordiner,Peter J. Sarre,Arfon M. Smith,Tom A. Bell,Serena Viti
Physics , 2012, DOI: 10.1093/mnras/sts310
Abstract: Ultra-high spectral resolution observations of time-varying interstellar absorption towards {\kappa} Vel are reported, using the Ultra-High Resolution Facility on the Anglo-Australian Telescope. Detections of interstellar Ca I, Ca II, K I, Na I and CH are obtained, whilst an upper limit on the column density is reported for C_2. The results show continued increases in column densities of K I and Ca I since observations ~ 4 yr earlier, as the transverse motion of the star carried it ~ 10 AU perpendicular to the line of sight. Line profile models are fitted to the spectra and two main narrow components (A & B) are identified for all species except CH. The column density N(K I) is found to have increased by 82 +10-9 % between 1994 and 2006, whilst N(Ca I) is found to have increased by 32 +- 5 % over the shorter period of 2002-2006. The line widths are used to constrain the kinetic temperature to T_k,A < 671 +18-17 K and T_k,B < 114 +15-14 K. Electron densities are determined from the Ca I / Ca II ratio, which in turn place lower limits on the total number density of n_A > 7 * 10^3 cm^-3 and n_B > 2 * 10^4 cm^-3. Calcium depletions are estimated from the Ca I / K I ratio. Comparison with the chemical models of Bell et al. (2005) confirms the high number density, with n = 5 * 10^4 cm^-3 for the best-fitting model. The first measurements of diffuse interstellar bands (DIBs) towards this star are made at two epochs, but only an upper limit of < 40 % is placed on their variation over ~ 9 years. The DIBs are unusually weak for the measured E(B-V) and appear to exhibit similar behaviour to that seen in Orion. The ratio of equivalent widths of the {\lambda}5780 to {\lambda}5797 DIBs is amongst the highest known, which may indicate that the carrier of {\lambda}5797 is more sensitive to UV radiation than to local density.
Using VA data for research in persons with spinal cord injuries and disorders: Lessons from SCI QUERI
Bridget M. Smith, PhD,Charlesnika T. Evans, MPH, PhD,Philip Ullrich, PhD,Stephen Burns, MD
Journal of Rehabilitation Research and Development , 2010,
Abstract: The Department of Veterans Affairs (VA) provides integrated services to more than 25,000 veterans with spinal cord injuries and disorders (SCI/D). VA data offer great potential for providing insights into healthcare utilization and morbidity, and these capabilities are central to efforts to improve healthcare for veterans with SCI/D. The objective of this article is to introduce researchers to the use of VA data to examine questions related to SCI/D using examples from Spinal Cord Injury (SCI) Quality Enhancement Research Initiative studies. Sources of VA data available to investigators interested in SCI/D-related research include national-level VA administrative and clinical databases and primary data (medical record review, patient surveys). Methods used to identify veterans with SCI/D include the Allocation Resource Center cohort, the Spinal Cord Dysfunction (SCD) Registry, and the VA inpatient SCI flag; only 33% of veterans were included in all three groups (n = 12,306). While neurological level of SCI was unknown for approximately a third of veterans (from SCD Registry data alone), the percent decreased to 13% when augmented with diagnostic codes. Primary data can be used to augment other missing SCI data and to provide more detailed information about complications commonly associated with SCI/D.
A Randomized Controlled Pilot Study of Home-Based Step Training in Older People Using Videogame Technology
Daniel Schoene, Stephen R. Lord, Kim Delbaere, Connie Severino, Thomas A. Davies, Stuart T. Smith
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0057734
Abstract: Background Stepping impairments are associated with physical and cognitive decline in older adults and increased fall risk. Exercise interventions can reduce fall risk, but adherence is often low. A new exergame involving step training may provide an enjoyable exercise alternative for preventing falls in older people. Purpose To assess the feasibility and safety of unsupervised, home-based step pad training and determine the effectiveness of this intervention on stepping performance and associated fall risk in older people. Design Single-blinded two-arm randomized controlled trial comparing step pad training with control (no-intervention). Setting/Participants Thirty-seven older adults residing in independent-living units of a retirement village in Sydney, Australia. Intervention Intervention group (IG) participants were provided with a computerized step pad system connected to their TVs and played a step game as often as they liked (with a recommended dose of 2–3 sessions per week for 15–20 minutes each) for eight weeks. In addition, IG participants were asked to complete a choice stepping reaction time (CSRT) task once each week. Main Outcome Measures CSRT, the Physiological Profile Assessment (PPA), neuropsychological and functional mobility measures were assessed at baseline and eight week follow-up. Results Thirty-two participants completed the study (86.5%). IG participants played a median 2.75 sessions/week and no adverse events were reported. Compared to the control group, the IG significantly improved their CSRT (F31,1 = 18.203, p<.001), PPA composite scores (F31,1 = 12.706, p = 0.001), as well as the postural sway (F31,1 = 4.226, p = 0.049) and contrast sensitivity (F31,1 = 4.415, p = 0.044) PPA sub-component scores. In addition, the IG improved significantly in their dual-task ability as assessed by a timed up and go test/verbal fluency task (F31,1 = 4.226, p = 0.049). Conclusions Step pad training can be safely undertaken at home to improve physical and cognitive parameters of fall risk in older people without major cognitive and physical impairments. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN12611001081909.
IP-FCM Measures Physiologic Protein-Protein Interactions Modulated by Signal Transduction and Small-Molecule Drug Inhibition
Stephen E. P. Smith, Anya T. Bida, Tessa R. Davis, Hugues Sicotte, Steven E. Patterson, Diana Gil, Adam G. Schrum
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045722
Abstract: Protein-protein interactions (PPI) mediate the formation of intermolecular networks that control biological signaling. For this reason, PPIs are of outstanding interest in pharmacology, as they display high specificity and may represent a vast pool of potentially druggable targets. However, the study of physiologic PPIs can be limited by conventional assays that often have large sample requirements and relatively low sensitivity. Here, we build on a novel method, immunoprecipitation detected by flow cytometry (IP-FCM), to assess PPI modulation during either signal transduction or pharmacologic inhibition by two different classes of small-molecule compounds. First, we showed that IP-FCM can detect statistically significant differences in samples possessing a defined PPI change as low as 10%. This sensitivity allowed IP-FCM to detect a PPI that increases transiently during T cell signaling, the antigen-inducible interaction between ZAP70 and the T cell antigen receptor (TCR)/CD3 complex. In contrast, IP-FCM detected no ZAP70 recruitment when T cells were stimulated with antigen in the presence of the src-family kinase inhibitor, PP2. Further, we tested whether IP-FCM possessed sufficient sensitivity to detect the effect of a second, rare class of compounds called SMIPPI (small-molecule inhibitor of PPI). We found that the first-generation non-optimized SMIPPI, Ro-26-4550, inhibited the IL-2:CD25 interaction detected by IP-FCM. This inhibition was detectable using either a recombinant CD25-Fc chimera or physiologic full-length CD25 captured from T cell lysates. Thus, we demonstrate that IP-FCM is a sensitive tool for measuring physiologic PPIs that are modulated by signal transduction and pharmacologic inhibition.
Driving down the Detection Limit in Microstructured Fiber?Based Chemical Dip Sensors
Erik P. Schartner,Heike Ebendorff-Heidepriem,Stephen C. Warren-Smith,Richard T. White,Tanya M. Monro
Sensors , 2011, DOI: 10.3390/s110302961
Abstract: We present improvements to fluorescence sensing in soft-glass microstructured optical fibers that result in significantly improved sensitivity relative to previously published results. Concentrations of CdSe quantum dots down to 10 pM levels have been demonstrated. We show that the primary limitation to the sensitivity of these systems is the intrinsic fluorescence of the glass itself.
Community Acceptance of Tsetse Control Baits: A Qualitative Study in Arua District, North West Uganda
Vanja Kovacic ,Inaki Tirados,Johan Esterhuizen,Clement T. N. Mangwiro,Stephen J. Torr,Michael J. Lehane,Helen Smith
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0002579
Abstract: Background There is renewed vigour in efforts to eliminate neglected tropical diseases including sleeping sickness (human African trypanosomiasis or HAT), including attempts to develop more cost-effective methods of tsetse control. In the West Nile region of Uganda, newly designed insecticide-treated targets are being deployed over an area of ~500 km2. The operational area covers villages where tsetse control has not been conducted previously. The effectiveness of the targets will depend, in part, on their acceptance by the local community. Methodology/Principal Findings We assessed knowledge, perceptions and acceptance of tsetse baits (traps, targets) in villages where they had or had not been used previously. We conducted sixteen focus group discussions with male and female participants in eight villages across Arua District. Discussions were audio recorded, translated and transcribed. We used thematic analysis to compare the views of both groups and identify salient themes. Conclusions/Significance Despite the villages being less than 10 km apart, community members perceived deployed baits very differently. Villagers who had never seen traps before expressed fear, anxiety and panic when they first encountered them. This was related to associations with witchcraft and “ghosts from the river” which are traditionally linked with physical or mental illness, death and misfortune. By contrast, villagers living in areas where traps had been used previously had positive attitudes towards them and were fully aware of their purpose and benefits. The latter group reported that they had similar negative perceptions when tsetse control interventions first started a decade ago. Our results suggest that despite their proximity, acceptance of traps varies markedly between villages and this is related to the duration of experience with tsetse control programs. The success of community-based interventions against tsetse will therefore depend on early engagements with communities and carefully designed sensitization campaigns that reach all communities, especially those living in areas new to such interventions.
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