2,799 research outputs found
Risk, precaution and science: towards a more constructive policy debate. Talking point on the precautionary principle
Few issues in contemporary risk policy are as momentous or contentious as the precautionary principle. Since it first emerged in German environmental policy, it has been championed by environmentalists and consumer protection groups, and resisted by the industries they oppose (Raffensperger & Tickner, 1999). Various versions of the principle now proliferate across different national and international jurisdictions and policy areas (Fisher, 2002). From a guiding theme in European Commission (EC) environmental policy, it has become a general principle of EC law (CEC, 2000; Vos & Wendler, 2006). Its influence has extended from the regulation of environmental, technological and health risks to the wider governance of science, innovation and trade (O'Riordan & Cameron, 1994)
The point of maximum curvature as a marker for physiological time series
We present a geometric analysis of the model of Stirling. In particular we analyze the curvature of a heart rate time series in response to a step like increment in the exercise intensity. We present solutions for the point of maximum curvature which can be used as a marker of physiological interest. This marker defines the point after which the heart rate no longer continues to rapidly rise and instead follows either a steady state or slow rise. These methods are then applied to find analytic solutions for a mono exponential model which is commonly used in the literature to model the response to a moderate exercise intensity. Numerical solutions are then found for the full model and parameter values presented in Stirling
HepData and JetWeb: HEP data archiving and model validation
The CEDAR collaboration is extending and combining the JetWeb and HepData
systems to provide a single service for tuning and validating models of
high-energy physics processes. The centrepiece of this activity is the fitting
by JetWeb of observables computed from Monte Carlo event generator events
against their experimentally determined distributions, as stored in HepData.
Caching the results of the JetWeb simulation and comparison stages provides a
single cumulative database of event generator tunings, fitted against a wide
range of experimental quantities. An important feature of this integration is a
family of XML data formats, called HepML.Comment: 4 pages, 0 figures. To be published in proceedings of CHEP0
The CEDAR Project
We describe the plans and objectives of the CEDAR project (Combined e-Science
Data Analysis Resource for High Energy Physics) newly funded by the PPARC
e-Science programme in the UK. CEDAR will combine the strengths of the well
established and widely used HEPDATA database of HEP data and the innovative
JetWeb data/Monte Carlo comparison facility, built on the HZTOOL package, and
will exploit developing grid technology. The current status and future plans of
both of these individual sub-projects within the CEDAR framework are described,
showing how they will cohesively provide (a) an extensive archive of Reaction
Data, (b) validation and tuning of Monte Carlo programs against these reaction
data sets, and (c) a validated code repository for a wide range of HEP code
such as parton distribution functions and other calculation codes used by
particle physicists. Once established it is envisaged CEDAR will become an
important Grid tool used by LHC experimentalists in their analyses and may well
serve as a model in other branches of science where there is a need to compare
data and complex simulations.Comment: 4 pages, 4 postscript figures, uses CHEP2004.cls. Presented at
Computing in High-Energy Physics (CHEP'04), Interlaken, Switzerland, 27th
September - 1st October 200
MERLIN observations of relativistic ejections from GRS 1915+105
We present high resolution MERLIN radio images of multiple relativistic
ejections from GRS 1915+105 in 1997 October / November. The observations were
made at a time of complex radio behaviour, corresponding to multiple
optically-thin outbursts and several days of rapid radio flux oscillations. The
radio imaging resolved four major ejection events from the system. As
previously reported from earlier VLA observations of the source, we observe
apparent superluminal motions resulting from intrinsically relativistic motions
of the ejecta. However, our measured proper motions are significantly greater
than those observed on larger angular scales with the VLA. Under the assumption
of an intrinsically symmetric ejection, we can place an upper limit on the
distance to GRS 1915+105 of 11.2 +/- 0.8 kpc. Solutions for the velocities
unambiguously require a higher intrinsic speed by about 0.1c than that derived
from the earlier VLA observations, whilst the angle to the line-of-sight is not
found to be significantly different. At a distance of 11 kpc, we obtain
solutions of v = 0.98 (-0.05,+0.02)c and theta = 66 +/- 2 degrees. The jet also
appears to be curved on a scale which corresponds to a period of around 7 days.
We observe significant evolution of the linear polarisation of the approaching
component, with large rotations in position angle and a general decrease in
fractional polarisation. The power input into the formation of the jet is very
large, >10^38 erg/s at 11 kpc for a pair plasma. If the plasma contains a cold
proton for each electron, then the mass outflow rate, >10^18 g/sec is
comparable to inflow rates previously derived from X-ray spectral fits.Comment: 14 pages, 7 figures. Accepted for publication in MNRA
Direct Nitrous Oxide Emissions From Tropical And Sub-Tropical Agricultural Systems : A Review and Modelling of Emission Factors
We acknowledge the financial support from the CGIAR Research Programs on Climate Change, Agriculture and Food Security (CCAFS). Grant ref. n. P25.Peer reviewedPublisher PD
HepForge: A lightweight development environment for HEP software
Setting up the infrastructure to manage a software project can become a task
as significant writing the software itself. A variety of useful open source
tools are available, such as Web-based viewers for version control systems,
"wikis" for collaborative discussions and bug-tracking systems, but their use
in high-energy physics, outside large collaborations, is insubstantial.
Understandably, physicists would rather do physics than configure project
management tools.
We introduce the CEDAR HepForge system, which provides a lightweight
development environment for HEP software. Services available as part of
HepForge include the above-mentioned tools as well as mailing lists, shell
accounts, archiving of releases and low-maintenance Web space. HepForge also
exists to promote best-practice software development methods and to provide a
central repository for re-usable HEP software and phenomenology codes.Comment: 3 pages, 0 figures. To be published in proceedings of CHEP06. Refers
to the HepForge facility at http://hepforge.cedar.ac.u
Pregnancy outcomes in Benghazi, Libya, before and during the armed conflict in 2011
Stressful life events experienced by pregnant women may lead to adverse obstetric outcomes. This study in Benghazi compared the rates of preterm, low-birth-weight and caesarean-section births at Al-Jamhouria hospital in the months before and during the armed conflict in Libya in 2011. Data were collected on all women admitted to the delivery ward during February to May 2011 (the months of the most active fighting in the city) (n = 7096), and October to December 2010 (the months immediately before the war) (n = 5935). Compared with the preceding months there was a significant rise during the conflict in the rate of deliveries involving preterm (3.6% versus 2.5%) and low-birth-weight (10.1% versus 8.5%) infants and caesarean sections (26.9% versus 25.3%). Psychosocial stress may have been a factor (among others) in an increase in negative pregnancy outcomes, and obstetric hospitals should be aware of these issues in times of war
A transient relativistic radio jet from Cygnus X-1
We report the first observation of a transient relativistic jet from the
canonical black hole candidate, Cygnus X-1, obtained with the Multi-Element
Radio-Linked Interferometer Network (MERLIN). The jet was observed in only one
of six epochs of MERLIN imaging of the source during a phase of repeated X-ray
spectral transitions in 2004 Jan--Feb, and this epoch corresponded to the
softest 1.5-12 keV X-ray spectrum. With only a single epoch revealing the jet,
we cannot formally constrain its velocity. Nevertheless, several lines of
reasoning suggest that the jet was probably launched 0.5-4.0 days before this
brightening, corresponding to projected velocities of 0.2c < v_app < 1.6c, and
an intrinsic velocity of > 0.3c. We also report the occurrence of a major radio
flare from Cyg X-1, reaching a flux density of ~120 mJy at 15 GHz, and yet not
associated with any resolvable radio emission, despite a concerted effort with
MERLIN. We discuss the resolved jet in terms of the recently proposed 'unified
model' for the disc-jet coupling in black hole X-ray binaries, and tentatively
identify the 'jet line' for Cyg X-1. The source is consistent with the model in
the sense that a steady jet appears to persist initially when the X-ray
spectrum starts softening, and that once the spectral softening is complete the
core radio emission is suppressed and transient ejecta / shock observed.
However, there are some anomalies, and Cyg X-1 clearly does not behave like a
normal black hole transient in progressing to the canonical soft / thermal
state once the ejection event has happened.Comment: Accepted for publication in MNRA
Developing Community Nursing Practice: Promoting Case Management and Skill Enhancement to Support Shifting the Balance of Care
Five inter-related projects were commissioned by NHS Highland to further knowledge and understanding of key issues that can be used to inform particular aspects of care delivery that supports the community nurse review. The five projects reflect some of the core elements that have been identified to maximise nurses’ contributions in community settings (Scottish Executive 2006a). The projects were designed to provide qualitative evidence of the views of community nurses regarding case management and to support the delivery of skills in community nursing practice. Additionally community nurses identified the knowledge and skills required to develop practice tools that would support areas of generalist and specialist practice, specifically around child welfare and long term conditions (heart care). The five projects were: i. Literature review on case management models in Community Nursing. ii. Action research project to support implementation of Case Management Models in community nursing. iii. Literature review on practitioners with special interest. iv. Research to inform development of practitioner tools for child protection and long term conditions (heart care). v. Research to explore skills transition to support Shifting the Balance of Care. This project focused on 3 key initiatives that are influencing community nursing and it was apparent that they all shared common goals and challenges of implementation. For this reason, it was clear that any development in service provision would impact on, and articulate with, other health, social and profession based changes and could not be implemented in isolation from other related developments that underpin shifting the balance of care. Nurses in the studies articulated insightful challenges for shifting the balance of care, and related role developments, but these were, in the majority, followed by offering practical solutions
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