1,047 research outputs found
Substorm associated radar auroral surges: a statistical study and possible generation model
International audienceSubstorm-associated radar auroral surges (SARAS) are a short lived (15?90 minutes) and spatially localised (~5° of latitude) perturbation of the plasma convection pattern observed within the auroral E-region. The understanding of such phenomena has important ramifications for the investigation of the larger scale plasma convection and ultimately the coupling of the solar wind, magnetosphere and ionosphere system. A statistical investigation is undertaken of SARAS, observed by the Sweden And Britain Radar Experiment (SABRE), in order to provide a more extensive examination of the local time occurrence and propagation characteristics of the events. The statistical analysis has determined a local time occurrence of observations between 1420 MLT and 2200 MLT with a maximum occurrence centred around 1700 MLT. The propagation velocity of the SARAS feature through the SABRE field of view was found to be predominately L-shell aligned with a velocity centred around 1750 m s?1 and within the range 500 m s?1 and 3500 m s?1. This comprehensive examination of the SARAS provides the opportunity to discuss, qualitatively, a possible generation mechanism for SARAS based on a proposed model for the production of a similar phenomenon referred to as sub-auroral ion drifts (SAIDs). The results of the comparison suggests that SARAS may result from a similar geophysical mechanism to that which produces SAID events, but probably occurs at a different time in the evolution of the event
FlowR: Aspect oriented programming for information flow control in ruby
This paper reports on our experience with providing Information Flow Control (IFC) as a library. Our aim was to support the use of an unmodified Platform as a Service (PaaS) cloud infrastructure by IFC-aware web applications. We discuss how Aspect Oriented Programming (AOP) overcomes the limitations of RubyTrack, our first approach. Although use of AOP has been mentioned as a possibility in past IFC literature we believe this paper to be the first illustration of how such an implementation can be attempted. We discuss how we built FlowR (Information Flow Control for Ruby), a library extending Ruby to provide IFC primitives using AOP via the Aquarium open source library. Previous attempts at providing IFC as a language extension required either modification of an interpreter or significant code rewriting. FlowR provides a strong separation between functional implementation and security constraints which supports easier development and maintenance; we illustrate with practical examples. In addition, we provide new primitives to describe IFC constraints on objects, classes and methods that, to our knowledge, are not present in related work and take full advantage of an object oriented language (OO language). The experience reported here makes us confident that the techniques we use for Ruby can be applied to provide IFC for any Object Oriented Program (OOP) whose implementation language has an AOP library.This is the final version published by ACM in Proceedings of the 13th international conference on Modularity (MODULARITY '14). ACM, New York, NY, USA, 37-48, available from the ACM Digital Library here: http://dl.acm.org/citation.cfm?doid=2577080.2577090
Octupole transitions in the 208Pb region
The 208Pb region is characterised by the existence of collective octupole states.
Here we populated such states in 208Pb + 208Pb deep-inelastic reactions. γ-ray angular
distribution measurements were used to infer the octupole character of several E3 transitions.
The octupole character of the 2318 keV 17− → 14+ in 208Pb, 2485 keV 19/2
− → 13/2
+ in
207Pb, 2419 keV 15/2
− → 9/2
+ in 209Pb and 2465 keV 17/2
+ → 11/2
− in 207Tl transitions was
demonstrated for the first time. In addition, shell model calculations were performed using two
different sets of two-body matrix elements. Their predictions were compared with emphasis on
collective octupole states.This work is supported by the Science and Technology Facilities Council
(STFC), UK, US Department of Energy, Office of Nuclear Physics, under Contract No. DEAC02-06CH11357
and DE-FG02-94ER40834, NSF grant PHY-1404442
Diagnosing cancer in primary care: results from the National Cancer Diagnosis Audit
BACKGROUND: Continual improvements in diagnostic processes are needed to minimise the proportion of patients with cancer who experience diagnostic delays. Clinical audit is a means of achieving this. AIM: To characterise key aspects of the diagnostic process for cancer and to generate baseline measures for future re-audit. DESIGN AND SETTING: Clinical audit of cancer diagnosis in general practices in England. METHOD: Information on patient and tumour characteristics held in the English National Cancer Registry was supplemented by information from GPs in participating practices. Data items included diagnostic timepoints, patient characteristics, and clinical management. RESULTS: Data were collected on 17 042 patients with a new diagnosis of cancer during 2014 from 439 practices. Participating practices were similar to non-participating ones, particularly regarding population age, urban/rural location, and practice-based patient experience measures. The median diagnostic interval for all patients was 40 days (interquartile range [IQR] 15-86 days). Most patients were referred promptly (median primary care interval 5 days [IQR 0-27 days]). Where GPs deemed diagnostic delays to have occurred (22% of cases), patient, clinician, or system factors were responsible in 26%, 28%, and 34% of instances, respectively. Safety netting was recorded for 44% of patients. At least one primary care-led investigation was carried out for 45% of patients. Most patients (76%) had at least one existing comorbid condition; 21% had three or more. CONCLUSION: The findings identify avenues for quality improvement activity and provide a baseline for future audit of the impact of 2015 National Institute for Health and Care Excellence guidance on management and referral of suspected cancer
Spin Glass Ordering in Diluted Magnetic Semiconductors: a Monte Carlo Study
We study the temperature-dilution phase diagram of a site-diluted Heisenberg
antiferromagnet on a fcc lattice, with and without the Dzyaloshinskii-Moriya
anisotropic term, fixed to realistic microscopic parameters for (IIB=Cd, Hg, Zn). We show that the dipolar Dzyaloshinskii-Moriya anisotropy
induces a finite-temperature phase transition to a spin glass phase, at
dilutions larger than 80%. The resulting probability distribution of the order
parameter P(q) is similar to the one found in the cubic lattice
Edwards-Anderson Ising model. The critical exponents undergo large finite size
corrections, but tend to values similar to the ones of the
Edwards-Anderson-Ising model.Comment: 4 pages plus 3 postscript figure
Baseline Groundwater Quality : a comparison of selected British and Norwegian aquifers
The aim of this work is to present a discussion on the concept of baseline and to compare the
natural variations in inorganic water quality present in a selection of British and Norwegian
groundwaters. The use of boxplots and cumulative frequency plots facilitates comparison
between individual rock aquifers, different regions with divergent geological and climatic
records, and between various elements and parameters. The range of baseline concentrations is
often large; e.g. uranium concentrations in Precambrian granitic groundwaters in Norway spans
almost 4 orders of magnitude.
Baseline values are useful as a means to assess pollution or to set a realistic base for remediation.
The EU Maximum Admissible Concentrations (MAC values) of drinking water should be set on
toxicological criteria only, as natural unpolluted groundwater sometimes contain elements in
concentrations deemed to be harmful.
Most of the hard rock groundwaters in Norway have relatively high pH compared with those of
the UK. Na-HCO3 type waters seem to be much more common in Norway than in the UK where
Ca-HCO3 type water dominate. High F, U and Rn concentrations are found in many granitic and
sedimentary groundwaters in Norway, while Ba concentrations tend to be higher in the UK
sedimentary aquifers.
Universal baseline values do not exist for any element and statistical representative sampling
from all aquifers is necessary to establish reliable knowledge about the natural groundwater
quality in each area. A suggested series of methodologies are suggested which can be applied to
aquifers where the effects of anthropogenic pollution are present. There is a strong need for timeseries
data on a wide range of parameters to ascertain the long-term effects of human activity on
groundwater quality. The trends of groundwater quality with depth should also be studied more
thoroughly.
In order for a European wide policy to be implemented it is necessary to establish protocols for
criteria related to data quality, sampling and analytical wor
Designing programs for eliminating canine rabies from islands: Bali, Indonesia as a case study
<p>Background:
Canine rabies is one of the most important and feared zoonotic diseases in the world. In some regions rabies elimination is being successfully coordinated, whereas in others rabies is endemic and continues to spread to uninfected areas. As epidemics emerge, both accepted and contentious control methods are used, as questions remain over the most effective strategy to eliminate rabies. The Indonesian island of Bali was rabies-free until 2008 when an epidemic in domestic dogs began, resulting in the deaths of over 100 people. Here we analyze data from the epidemic and compare the effectiveness of control methods at eliminating rabies.</p>
<p>Methodology/Principal Findings:
Using data from Bali, we estimated the basic reproductive number, R0, of rabies in dogs, to be ~1·2, almost identical to that obtained in ten–fold less dense dog populations and suggesting rabies will not be effectively controlled by reducing dog density. We then developed a model to compare options for mass dog vaccination. Comprehensive high coverage was the single most important factor for achieving elimination, with omission of even small areas (<0.5% of the dog population) jeopardizing success. Parameterizing the model with data from the 2010 and 2011 vaccination campaigns, we show that a comprehensive high coverage campaign in 2012 would likely result in elimination, saving ~550 human lives and ~$15 million in prophylaxis costs over the next ten years.</p>
<p>Conclusions/Significance:
The elimination of rabies from Bali will not be achieved through achievable reductions in dog density. To ensure elimination, concerted high coverage, repeated, mass dog vaccination campaigns are necessary and the cooperation of all regions of the island is critical. Momentum is building towards development of a strategy for the global elimination of canine rabies, and this study offers valuable new insights about the dynamics and control of this disease, with immediate practical relevance.</p>
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