6,667 research outputs found
Setting directions for capacity building in primary health care: a survey of a research network
BACKGROUND: The South Australian Research Network 'SARNet' aims to build research capacity in primary health care, as part of a national government-funded strategy to integrate research into clinical practice. Internationally, research networks have been a fundamental part of research culture change, and a variety of network models exist. The 'SARNet' model uses a whole system, multidisciplinary approach to capacity building and supports individuals and groups. We undertook a descriptive baseline survey in order to understand the background and needs of SARNet members and to tailor network activities towards those needs. METHODS: A questionnaire survey, assessing members' professional background, research experience, and interest in research development and training, was sent to all members who joined the network in its first year. The visual 'research spider' tool was used to ascertain members' experience in ten core research skills, as well as their interest in developing these skills. Individuals were asked to classify themselves into one of four categories of researchers, based on previous research experience. These self-assessment categories ranged from non-participant to academic. RESULTS: Network membership was diverse. Of the 89 survey participants, 55% were general practitioners or allied health professionals. Overall, most survey respondents indicated little to moderate experience in 7 out of the 10 skills depicted in the 'research spider'. In comparison, respondents were generally highly interested in developing their research skills in all areas. Respondents' research skills correlated significantly with their self-assessed category of research participation (Spearman rank correlation, r = 0.82, p < 0.0005). Correlations between research category and publication record (Gamma association, Ī³ = 0.53, p < 0.0005) or funding record (Gamma association, Ī³ = 0.62, p < 0.0005) supported the internal validity of the survey instrument. CONCLUSION: Literature describing evaluation of the impact of networks is scarce. Our survey questionnaire could provide a useful instrument for evaluation of both networks and capacity building initiatives. The survey including the 'research spider' tool provided valuable information about members' needs and interest in strategies to develop their research skills. Initial needs analyses as well as on-going evaluation of network activities are important to include into the business plans of research networks, in order to ensure the network's effectiveness and support of its membership
A Multi Agent Model for the Limit Order Book Dynamics
In the present work we introduce a novel multi-agent model with the aim to
reproduce the dynamics of a double auction market at microscopic time scale
through a faithful simulation of the matching mechanics in the limit order
book. The agents follow a noise decision making process where their actions are
related to a stochastic variable, "the market sentiment", which we define as a
mixture of public and private information. The model, despite making just few
basic assumptions over the trading strategies of the agents, is able to
reproduce several empirical features of the high-frequency dynamics of the
market microstructure not only related to the price movements but also to the
deposition of the orders in the book.Comment: 20 pages, 11 figures, in press European Physical Journal B (EPJB
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Auroral bright spot sequence near 1400 MLT: Coordinated optical and ion drift observations
Optical observations of a dayside auroral brightening sequence, by means of all-sky TV cameras and meridian scanning photometers, have been combined with EISCAT ion drift observations within the same invariant latitude-MLT sector. The observations were made during a January 1989 campaign by utilizing the high F region ion densities during the maximum phase of the solar cycle. The characteristic intermittent optical events, covering ā¼300 km in east-west extent, move eastward (antisunward) along the poleward boundary of the persistent background aurora at velocities of ā¼1.5 km sā1 and are associated with ion flows which swing from eastward to westward, with a subsequent return to eastward, during the interval of a few minutes when there is enhanced auroral emission within the radar field of view. The breakup of discrete auroral forms occurs at the reversal (negative potential) that forms between eastward plasma flow, maximizing near the persistent arc poleward boundary, and strong transient westward flow to the south. The reported events, covering a 35 min interval around 1400 MLT, are embedded within a longer period of similar auroral activity between 0830 (1200 MLT) and 1300 UT (1600 MLT). These observations are discussed in relation to recent models of boundary layer plasma dynamics and the associated magnetosphere-ionosphere coupling. The ionospheric events may correspond to large-scale wave like motions of the low-latitude boundary layer (LLBL)/plasma sheet (PS) boundary. On the basis of this interpretation the observed spot size, speed and repetition period (ā¼10 min) give a wavelength (the distance between spots) of ā¼900 km in the present case. The events can also be explained as ionospheric signatures of newly opened flux tubes associated with reconnection bursts at the magnetopause near 1400 MLT. We also discuss these data in relation to random, patchy reconnection (as has recently been invoked to explain the presence of the sheathlike plasma on closed field lines in the LLBL). In view of the lack of IMF data, and the existing uncertainty on the location of the open-closed field line boundary relative to the optical events, an unambiguous discrimination between the different alternatives is not easily obtained
Cellular automaton rules conserving the number of active sites
This paper shows how to determine all the unidimensional two-state cellular
automaton rules of a given number of inputs which conserve the number of active
sites. These rules have to satisfy a necessary and sufficient condition. If the
active sites are viewed as cells occupied by identical particles, these
cellular automaton rules represent evolution operators of systems of identical
interacting particles whose total number is conserved. Some of these rules,
which allow motion in both directions, mimic ensembles of one-dimensional
pseudo-random walkers. Numerical evidence indicates that the corresponding
stochastic processes might be non-Gaussian.Comment: 14 pages, 5 figure
Multibody aircraft study, volume 2
The potential benefits of a multibody aircraft when compared to a single body aircraft are presented. The analyses consist principally of a detailed point design analysis of three multibody and one single body aircraft, based on a selected payload of 350,000 kg (771,618 lb), for final aircraft definitions; sensitivity studies to evaluate the effects of variations in payload, wing semispan body locations, and fuel price; recommendations as to the research and technology requirements needed to validate the multibody concept. Two, two body, one, three body, and one single body aircraft were finalized for the selected payload, with DOC being the prime figure of merit. When compared to the single body, the multibody aircraft showed a reduction in DOC by as much as 11.3 percent. Operating weight was reduced up to 14 percent, and fly away cost reductions ranged from 8.6 to 13.4 percent. Weight reduction, hence cost, of the multibody aircraft resulted primarily from the wing bending relief afforded by the bodies being located outboard on the wing
Studies of the limit order book around large price changes
We study the dynamics of the limit order book of liquid stocks after
experiencing large intra-day price changes. In the data we find large
variations in several microscopical measures, e.g., the volatility the bid-ask
spread, the bid-ask imbalance, the number of queuing limit orders, the activity
(number and volume) of limit orders placed and canceled, etc. The relaxation of
the quantities is generally very slow that can be described by a power law of
exponent . We introduce a numerical model in order to understand
the empirical results better. We find that with a zero intelligence deposition
model of the order flow the empirical results can be reproduced qualitatively.
This suggests that the slow relaxations might not be results of agents'
strategic behaviour. Studying the difference between the exponents found
empirically and numerically helps us to better identify the role of strategic
behaviour in the phenomena.Comment: 19 pages, 7 figure
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