90 research outputs found
Type II Shocks Characteristics: Comparison with associated CMEs and Flares
A number of metric (100-650 MHz) typeII bursts was recorded by the ARTEMIS-IV
radiospectrograph in the 1998-2000 period; the sample includes both CME driven
shocks and shocks originating from flare blasts. We study their characteristics
in comparison with characteristics of associated CMEs and flares.Comment: Recent Advances in Astronomy and Astrophysics: 7th International
Conference of the Hellenic Astronomical Society. AIP Conference Proceedings,
Volume 848, pp. 238-242 (2006
Space storm measurements of the July 2005 solar extreme events from the low corona to the Earth
The Athens Neutron Monitor Data Processing (ANMODAP) Center recorded an
unusual Forbush decrease with a sharp enhancement of cosmic ray intensity right
after the main phase of the Forbush decrease on 16 July 2005, followed by a
second decrease within less than 12 h. This exceptional event is neither a
ground level enhancement nor a geomagnetic effect in cosmic rays. It rather
appears as the effect of a special structure of interplanetary disturbances
originating from a group of coronal mass ejections (CMEs) in the 13-14 July
2005 period. The initiation of the CMEs was accompanied by type IV radio bursts
and intense solar flares (SFs) on the west solar limb (AR 786); this group of
energetic phenomena appears under the label of Solar Extreme Events of July
2005. We study the characteristics of these events using combined data from
Earth (the ARTEMIS IV radioheliograph, the Athens Neutron Monitor (ANMODAP)),
space (WIND/WAVES) and data archives. We propose an interpretation of the
unusual Forbush profile in terms of a magnetic structure and a succession of
interplanetary shocks interacting with the magnetosphere.Comment: Advances in Space Research, Volume 43, Issue 4, p. 600-60
Solar flares with and without SOHO/LASCO coronal mass ejections and type II shocks
We analyse of a set of radio rich (accompanied by type IV or II bursts) solar
flares and their association with SOHO/LASCO Coronal Mass Ejections in the
period 1998 2000. The intensity, impulsiveness and energetics of these events
are investigated. We find that, on the average, flares associated both with
type IIs and CMEs are more impulsive and more energetic than flares associated
with type IIs only (without CME reported), as well as flares accompanied by
type IV continua but not type II shocks. From the last two classes, flares with
type II bursts (without CMEs reported) are the shortest in duration and the
most impulsive.Comment: Advances in Space Research, Volume 38, Issue 5, p. 1007-101
The 17 January 2005 Complex Solar Radio Event Associated with Interacting Fast Coronal Mass Ejections
On 17 January 2005 two fast coronal mass ejections were recorded in close
succession during two distinct episodes of a 3B/X3.8 flare. Both were
accompanied by metre-to-kilometre type-III groups tracing energetic electrons
that escape into the interplanetary space and by decametre-to-hectometre type-
II bursts attributed to CME-driven shock waves. A peculiar type-III burst group
was observed below 600 kHz 1.5 hours after the second type III group. It
occurred without any simultaneous activity at higher frequencies, around the
time when the two CMEs were expected to interact. We associate this emission
with the interaction of the CMEs at heliocentric distances of about 25 R\odot.
Near-relativistic electrons observed by the EPAM experiment onboard ACE near 1
AU revealed successive particle releases that can be associated with the two
flare/CME events and the low-frequency type-III burst at the time of CME
interaction. We compare the pros and cons of shock acceleration and
acceleration in the course of magnetic reconnection for the escaping electron
beams revealed by the type III bursts and for the electrons measured in situ.Comment: 20 pages 7 Figures, Accepted for publication to Solar Physics,
Topical Issue 'Radio Observations and Modelling
Quasi-Newton methods for atmospheric chemistry simulations: implementation in UKCA UM vn10.8
A key and expensive part of coupled atmospheric chemistry–climate model
simulations is the integration of gas-phase chemistry, which involves dozens
of species and hundreds of reactions. These species and reactions form a
highly coupled network of differential equations (DEs). There exist orders of
magnitude variability in the lifetimes of the different species present in
the atmosphere, and so solving these DEs to obtain robust numerical solutions
poses a stiff problem. With newer models having more species and
increased complexity, it is now becoming increasingly important to have
chemistry solving schemes that reduce time but maintain accuracy. While a
sound way to handle stiff systems is by using implicit DE solvers, the
computational costs for such solvers are high due to internal iterative
algorithms (e.g. Newton–Raphson methods). Here, we propose an approach for
implicit DE solvers that improves their convergence speed and robustness with
relatively small modification in the code. We achieve this by blending the
existing Newton–Raphson (NR) method with quasi-Newton (QN) methods, whereby
the QN routine is called only on selected iterations of the solver. We test
our approach with numerical experiments on the UK Chemistry and Aerosol
(UKCA) model, part of the UK Met Office Unified Model suite, run in both an
idealised box-model environment and under realistic 3-D atmospheric
conditions. The box-model tests reveal that the proposed method reduces the
time spent in the solver routines significantly, with each QN call costing
27 % of a call to the full NR routine. A series of experiments over a range
of chemical environments was conducted with the box model to find the optimal
iteration steps to call the QN routine which result in the greatest reduction
in the total number of NR iterations whilst minimising the chance of causing
instabilities and maintaining solver accuracy. The 3-D simulations show that
our moderate modification, by means of using a blended method for the
chemistry solver, speeds up the chemistry routines by around 13 %,
resulting in a net improvement in overall runtime of the full model by
approximately 3 % with negligible loss in the accuracy. The blended QN
method also improves the robustness of the solver, reducing the number of
grid cells which fail to converge after 50 iterations by 40 %. The relative
differences in chemical concentrations between the control run and that using
the blended QN method are of order ∼  10−7 for longer-lived
species, such as ozone, and below the threshold for solver convergence
(10−4) almost everywhere for shorter-lived species such as the hydroxyl
radical.</p
Evaluation of Aerosol Delivery of Nanosuspension for Pre-clinical Pulmonary Drug Delivery
Asthma and chronic obstructive pulmonary disease (COPD) are pulmonary diseases that are characterized by inflammatory cell infiltration, cytokine production, and airway hyper-reactivity. Most of the effector cells responsible for these pathologies reside in the lungs. One of the most direct ways to deliver drugs to the target cells is via the trachea. In a pre-clinical setting, this can be achieved via intratracheal (IT), intranasal (IN), or aerosol delivery in the desired animal model. In this study, we pioneered the aerosol delivery of a nanosuspension formulation in a rodent model. The efficiency of different dosing techniques and formulations to target the lungs were compared, and fluticasone was used as the model compound. For the aerosol particle size determination, a ten-stage cascade impactor was used. The mass median aerodynamic diameter (MMAD) was calculated based on the percent cumulative accumulation at each stage. Formulations with different particle size of fluticasone were made for evaluation. The compatibility of regular fluticasone suspension and nanosuspension for aerosol delivery was also investigated. The in vivo studies were conducted on mice with optimized setting. It was found that the aerosol delivery of fluticasone with nanosuspension was as efficient as intranasal (IN) dosing, and was able to achieve dose dependent lung deposition
Advancing tools to promote health equity across European Union regions : The EURO-HEALTHY project
Population health measurements are recognised as appropriate tools to support public health monitoring. Yet, there is still a lack of tools that offer a basis for policy appraisal and for foreseeing impacts on health equity. In the context of persistent regional inequalities, it is critical to ascertain which regions are performing best, which factors might shape future health outcomes and where there is room for improvement. Under the EURO-HEALTHY project, tools combining the technical elements of multi-criteria value models and the social elements of participatory processes were developed to measure health in multiple dimensions and to inform policies. The flagship tool is the Population Health Index (PHI), a multidimensional measure that evaluates health from the lens of equity in health determinants and health outcomes, further divided into sub-indices. Foresight tools for policy analysis were also developed, namely: (1) scenarios of future patterns of population health in Europe in 2030, combining group elicitation with the Extreme-World method and (2) a multi-criteria evaluation framework informing policy appraisal (case study of Lisbon). Finally, a WebGIS was built to map and communicate the results to wider audiences. The Population Health Index was applied to all European Union (EU) regions, indicating which regions are lagging behind and where investments are most needed to close the health gap. Three scenarios for 2030 were produced - (1) the 'Failing Europe' scenario (worst case/increasing inequalities), (2) the 'Sustainable Prosperity' scenario (best case/decreasing inequalities) and (3) the 'Being Stuck' scenario (the EU and Member States maintain the status quo). Finally, the policy appraisal exercise conducted in Lisbon illustrates which policies have higher potential to improve health and how their feasibility can change according to different scenarios. The article makes a theoretical and practical contribution to the field of population health. Theoretically, it contributes to the conceptualisation of health in a broader sense by advancing a model able to integrate multiple aspects of health, including health outcomes and multisectoral determinants. Empirically, the model and tools are closely tied to what is measurable when using the EU context but offering opportunities to be upscaled to other settings
Urban air pollution and emergency room admissions for respiratory symptoms: a case-crossover study in Palermo, Italy
<p>Abstract</p> <p>Background</p> <p>Air pollution from vehicular traffic has been associated with respiratory diseases. In Palermo, the largest metropolitan area in Sicily, urban air pollution is mainly addressed to traffic-related pollution because of lack of industrial settlements, and the presence of a temperate climate that contribute to the limited use of domestic heating plants. This study aimed to investigate the association between traffic-related air pollution and emergency room admissions for acute respiratory symptoms.</p> <p>Methods</p> <p>From January 2004 through December 2007, air pollutant concentrations and emergency room visits were collected for a case-crossover study conducted in Palermo, Sicily. Risk estimates of short-term exposures to particulate matter and gaseous ambient pollutants including carbon monoxide, nitrogen dioxide, and sulfur dioxide were calculated by using a conditional logistic regression analysis.</p> <p>Results</p> <p>Emergency departments provided data on 48,519 visits for respiratory symptoms. Adjusted case-crossover analyses revealed stronger effects in the warm season for the most part of the pollutants considered, with a positive association for PM<sub>10 </sub>(odds ratio = 1.039, 95% confidence interval: 1.020 - 1.059), SO<sub>2 </sub>(OR = 1.068, 95% CI: 1.014 - 1.126), nitrogen dioxide (NO<sub>2</sub>: OR = 1.043, 95% CI: 1.021 - 1.065), and CO (OR = 1.128, 95% CI: 1.074 - 1.184), especially among females (according to an increase of 10 μg/m<sup>3 </sup>in PM<sub>10</sub>, NO<sub>2</sub>, SO<sub>2</sub>, and 1 mg/m<sup>3 </sup>in CO exposure). A positive association was observed either in warm or in cold season only for PM<sub>10</sub>.</p> <p>Conclusions</p> <p>Our findings suggest that, in our setting, exposure to ambient levels of air pollution is an important determinant of emergency room (ER) visits for acute respiratory symptoms, particularly during the warm season. ER admittance may be considered a good proxy to evaluate the adverse effects of air pollution on respiratory health.</p
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