1,055 research outputs found
Remote sensing as an aid for marsh management: Lafouche parish, Louisiana
NASA aerial photography, primarily color infrared and color positive transparencies, was used in a study of marsh management practices and in comparing managed and unmanaged marsh areas. Weir locations for tidal control are recommended
Evidence for Superhumps in the Radio Light Curve of Algol and a New Model for Magnetic Activity in Algol Systems
Extensive radio data of two Algol systems and two RS CVn binaries were
re-analyzed. We found evidence for a new periodicity that we interpret as a
superhump in Algol, in which it may have been expected according to its
semi-detached nature and low binary mass ratio. This is the first detection of
the superhump phenomenon in the radio and the first observation of superhumps
in Algol systems. According to our result, the accretion disk in Algol
precesses in spite of its non-Keplerian nature and therefore this phenomenon is
not restricted to the classical Keplerian disks in compact binaries.We propose
that in Algol systems with short orbital periods, the disk is magnetically
active as well as the secondary star. The magnetic field in the disk originates
from amplification of the seed field in the magnetized material transferred
from the secondary. The disk and stellar fields interact with each other, with
reconnection of the field lines causing flares and particle acceleration.
Relativistic particles are trapped in the field and directed toward the polar
regions of the secondary star because of the dipole structure of its magnetic
field. Our proposed model for the magnetic activity in Algol systems provides a
simple explanation to the observed properties of Algol in the radio
wavelengths, and to the presence of quiescent gyrosynchrotron emission near the
polar region of the secondary star, where electrons are difficult to be
confined if the field lines are open as in normal single magnetic stars. We
propose that the superhump variation in the radio is generated by enhanced
reconnection when the elongated side of the elliptic disk is the closest to the
cool star. This leads to flares and enhancement in particle acceleration and is
manifested as stronger gyrosynchrotron radiation.Comment: 8 pages, 5 figures, ApJ, accepted, uses apjfonts.sty and
emulateapj5.sty, full abstract in pape
The Effect of Experiential Education on Pilots\u27 VFR into IMC Decision-Making
In aviation, safety is always a primary consideration, and this is especially true during a pilot’s flight training to instill that safety mentality. However, this means that pilots are restricted by safety policies from encountering difficult weather situations during their training, which could, potentially, improve their weather decision-making skills for avoiding future hazardous weather encounters. Thirty-six general aviation pilots of varying instrument flight experience (IF) were allocated, using stratified random sampling based on their IF, to one of three groups, a control group and two educational treatment intervention groups. The educational treatment interventions were designed to improve the participant’s ability in recognizing deteriorating weather (reducing visibility) conditions, to prevent flying from visual flight rules (VFR) into instrument meteorological conditions (IMC) by the use of experiential education. Intervention one was web-based only and intervention two was web and personal computer (PC) simulator based. Each pilot flew a simulated flight along a fjord in Alaska under visual flight rules in deteriorating visual weather that became instrument conditions. Type of intervention and experience-related demographic factors were analyzed to determine what factors contributed to safe weather-related decisions. Type of educational treatment intervention was found to be the only statistically significant demographic predictor of safe performance. Pilots who received the web-based only intervention were better able to assess deteriorating visibility and avoid instrument weather. Implications of this study and opportunities for future research are discussed
Spectroscopic evidence for the binary nature of AM CVn
We analysed archival spectroscopic data of AM CVn taken with the William
Herschel Telescope in 1996. In the literature two orbital periods for AM CVn
are proposed. A clear S-wave in the HeI 4471, 4387 and 4143 \AA lines is
revealed when the spectra are folded on the 1029 s period. No signature of this
S-wave is seen when folded on 1051 s. Doppler tomography of the line profiles
shows a clear signature of the hotspot. Using this we can constrain the value
of K_2 to lie between 210 and 280 km/s. Our work confirms the binary nature of
AM CVn beyond any doubt, establishes 1028.73 s as the true orbital period and
supports the interpretation of AM CVn as a permanent superhump system.Comment: Accepted by MNRA
Levels of evidence in plastic surgery – Trends and comparison with five other surgical specialties
Background: Categorising research by level of evidence (LOE) is an important evidence-based medicine initiative. Our objective was to assess the change in LOEs in plastic surgery from 2003 to 2013 and compared this with five other surgical specialties. Methods: A search for all research articles published in the top three general plastic surgery journals (ranked by impact factor) was conducted for 2003 and 2013. Articles were then labelled as LOE 1–5 and compared to other specialties. Results: Mean LOE for plastic surgery improved by 4.1 % from 3.86 (95 % confidence interval 3.81–3.91) to 3.70 (95 % confidence interval 3.64–3.74) from 2003 to 2013 respectively. All six surgical specialties improved their mean LOE (range 3.7 to 10.9 %). By mean LOE, plastic surgery continues to rank five out of six. Conclusions: Plastic surgery is tending towards higher levels of evidence at a slow pace. The specialty must continue to drive towards higher levels of evidence. Level of Evidence: Not ratable
Impacts of Bicycle Infrastructure in Mid-Sized Cities (IBIMS): protocol for a natural experiment study in three Canadian cities
Introduction: Bicycling is promoted as a transportation and population health strategy globally. Yet bicycling has low uptake in North America (1%–2% of trips) compared with European bicycling cities (15%–40% of trips) and shows marked sex and age trends. Safety concerns due to collisions with motor vehicles are primary barriers. To attract the broader population to bicycling, many cities are making investments in bicycle infrastructure. These interventions hold promise for improving population health given the potential for increased physical activity and improved safety, but such outcomes have been largely unstudied. In 2016, the City of Victoria, Canada, committed to build a connected network of infrastructure that separates bicycles from motor vehicles, designed to attract people of ‘all ages and abilities’ to bicycling. This natural experiment study examines the impacts of the City of Victoria’s investment in a bicycle network on active travel and safety outcomes. The specific objectives are to (1) estimate changes in active travel, perceived safety and bicycle safety incidents; (2) analyse spatial inequities in access to bicycle infrastructure and safety incidents; and (3) assess health-related economic benefits. Methods and analysis: The study is in three Canadian cities (intervention: Victoria; comparison: Kelowna, Halifax). We will administer population-based surveys in 2016, 2018 and 2021 (1000 people/city). The primary outcome is the proportion of people reporting bicycling. Secondary outcomes are perceived safety and bicycle safety incidents. Spatial analyses will compare the distribution of bicycle infrastructure and bicycle safety incidents across neighbourhoods and across time. We will also calculate the economic benefits of bicycling using WHO’s Health Economic Assessment Tool. Ethics and dissemination: This study received approval from the Simon Fraser University Office of Research Ethics (study no. 2016s0401). Findings will be disseminated via a website, presentations to stakeholders, at academic conferences and through peer-reviewed journal article
A Standardised Modular Approach for Site SCADA Applications within a Water Utility
Any large water treatment/production utility that employs autonomous plant as part of its processes will utilise supervisory control and data acquisition systems. These systems will generally be isolated from each other and will exist solely to serve the site they control and visualise. More often, they are delivered and developed organically through cost driven maintenance regimes, that prioritise on process risk rather than asset lifecycles. In some cases, this has led to variations in installed software and hardware applications, not only across a business enterprise, but also down to a site level. This is usually based on favoured products at the time of supply, and in turn requires a broader range of engineering skills to maintain and update. The previous adoption of a ‘fit and forget’ model has also led to large areas of unsupported computer assets within an organisation that further introduces ‘data risk’. As regulatory bodies start to impose stricter compliance measures on the water industry, so to the suppliers become more reliant upon their process data. This paper presents how a water utility has employed a modular approach and has set to standardise its SCADA assets across all business sectors. It reviews the hardware the systems are installed on, the software applications used to deliver the integration, and discusses how the software devices have been modelled and tagged in search of a common information model. All in line with their respective field assets. It also discusses some of the human factors surrounding the replacement of control systems
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Exploiting granular electrical energy data and the challenges a utility company faces with an ageing asset base
Thames Water; Brunel University London
Reach in and reach out : the story of the MSc in pipeline engineering at Newcastle University
This paper presents an unusual case of university-industry interaction whereby a group of small businesses came together to persuade a university to establish an MSc in Pipeline Engineering. We identify that the course contributed to regional development in four ways. Firstly, it provided graduates for local industry. Secondly, it linked local firms with pipeline engineers world wide and raised the region's profile within that network. Thirdly, it strengthened the research base of the university through the recruitment of pipeline engineers from industry and fourthly, it facilitated the possibility of joint research between the university and local firms. We question whether this model is transferable to other industry sectors/universities. We conclude that this outreach activity has been shaped by the 'reach-in' to the university of the local business community and propose a revised model of university interaction with regional industry. Traditionally universities have been seen as 'reaching out' to regional industry and the collaborations have been viewed as being instigated by the university and often research-based. Our revised model proposes an alternative mechanism whereby collaborations can be instigated by industry and through a teaching-route
High Speed Photometry of SDSS J013701.06-091234.9
We present high speed photometry of the Sloan Digital Sky Survey cataclysmic
variable SDSS J013701.06-091234.9 in quiescence and during its 2003 December
superoutburst. The orbital modulation at 79.71\pm0.01 min is double humped; the
superhump period is 81.702\pm0.007 min. Towards the end of the outburst late
superhumps with a period of 81.29\pm0.01 min were observed. We argue that this
is a system of very low mass transfer rate, and that it probably has a long
outburst interval.Comment: 5 pages, 8 figures. Accepted for publication in MNRA
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