4,927 research outputs found
Acute occupational phosphine intoxications : a retrospective study by the Belgian Poison Centre
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The role of oxygen ions in the formation of a bifurcated current sheet in the magnetotail
Cluster observations in the near-Earth magnetotail have shown that sometimes
the current sheet is bifurcated, i.e. it is divided in two layers. The
influence of magnetic turbulence on ion motion in this region is investigated
by numerical simulation, taking into account the presence of both protons and
oxygen ions. The magnetotail current sheet is modeled as a magnetic field
reversal with a normal magnetic field component , plus a three-dimensional
spectrum of magnetic fluctuations , which represents the
observed magnetic turbulence. The dawn-dusk electric field E is also
included. A test particle simulation is performed using different values of
, E and injecting two different species of particles, O
ions and protons. O ions can support the formation of a double current
layer both in the absence and for large values of magnetic fluctuations
( and , where B is the constant
magnetic field in the magnetospheric lobes).Comment: 8 pages, 8 figures. J. Geophys. Res., in pres
Global Response to Local Ionospheric Mass Ejection
We revisit a reported "Ionospheric Mass Ejection" using prior event observations to guide a global simulation of local ionospheric outflows, global magnetospheric circulation, and plasma sheet pressurization, and comparing our results with the observed global response. Our simulation framework is based on test particle motions in the Lyon-Fedder-Mobarry (LFM) global circulation model electromagnetic fields. The inner magnetosphere is simulated with the Comprehensive Ring Current Model (CRCM) of Fok and Wolf, driven by the transpolar potential developed by the LFM magnetosphere, and includes an embedded plasmaspheric simulation. Global circulation is stimulated using the observed solar wind conditions for the period 24-25 Sept 1998. This period begins with the arrival of a Coronal Mass Ejection, initially with northward, but later with southward interplanetary magnetic field. Test particles are launched from the ionosphere with fluxes specified by local empirical relationships of outflow to electrodynamic and particle precipitation imposed by the MIlD simulation. Particles are tracked until they are lost from the system downstream or into the atmosphere, using the full equations of motion. Results are compared with the observed ring current and a simulation of polar and auroral wind outflows driven globally by solar wind dynamic pressure. We find good quantitative agreement with the observed ring current, and reasonable qualitative agreement with earlier simulation results, suggesting that the solar wind driven global simulation generates realistic energy dissipation in the ionosphere and that the Strangeway relations provide a realistic local outflow description
Patient experience of supported computerized CBT in an inner-city IAPT service:A qualitative study
Computerized cognitive behavioural therapy (cCBT) has been developed to address economic and clinical issues around limited access to evidence-based therapy. Supported cCBT (variously termed iCBT or eCBT) has been developed to address issues with the effectiveness of, and engagement with, cCBT. There has been no in-depth qualitative exploration of the patient experience of eCBT within the UK, which might aid improving its effectiveness. The aim of this study was to explore patient experience of eCBT in one inner-city National Health Service (NHS) Improving Access to Psychological Therapies (IAPT) service using a semi-structured interview and Thematic Analysis methodology. Ten patients took part. Six main themes were identified: (1) Being Offered eCBT; (2) How eCBT Compares with Self-help; (3) The Patient's State of Mind; (4) The Relationship with the Supporter; (5) Preferring to Talk; (6) eCBT's Value as a Treatment. Participants in this study indicated a preference for face-to-face talking therapy, but were clear that they could form a therapeutic relationship via asynchronous messaging. They reported clinical benefit from the eCBT programme and online relationship, and acknowledged that accessing this immediately was valuable. Issues around the process of selecting patients for eCBT, including with regard to acknowledging or mitigating any negative emotional effects of eCBT, and how to offer and support users with it, are discussed.</p
MeV magnetosheath ions energized at the bow shock
A causal relationship between midlatitude magnetosheath energetic ions and bow shock magnetic geometry was previously established for ion energy up to 200 keV e−1 for the May 4, 1998, storm event. This study demonstrates that magnetosheath ions with energies above 200 keV up to 1 MeV simply extend the ion spectrum to form a power law tail. Results of cross-correlation analysis suggest that these ions also come directly from the quasi-parallel bow shock, not the magnetosphere. This is confirmed by a comparison of energetic ion fluxes simultaneously measured in the magnetosheath and at the quasi-parallel bow shock when both regions are likely connected by the magnetic field lines. We suggest that ions are accelerated at the quasi-parallel bow shock to energies as high as 1 MeV and subsequently transported into the magnetosheath during this event
New Constraints on Dispersive Form Factor Parameterizations from the Timelike Region
We generalize a recent model-independent form factor parameterization derived
from rigorous dispersion relations to include constraints from data in the
timelike region. These constraints dictate the convergence properties of the
parameterization and appear as sum rules on the parameters. We further develop
a new parameterization that takes into account finiteness and asymptotic
conditions on the form factor, and use it to fit to the elastic \pi
electromagnetic form factor. We find that the existing world sample of timelike
data gives only loose bounds on the form factor in the spacelike region, but
explain how the acquisition of additional timelike data or fits to other form
factors are expected to give much better results. The same parameterization is
seen to fit spacelike data extremely well.Comment: 24 pages, latex (revtex), 3 eps figure
ReCROP: bioinocula and CROPping systems: an integrated biotechnological approach for improving crop yield, biodiversity and REsilience of Mediterranean agro-ecosystems
The Mediterranean economy is highly dependent on agriculture. However, agricultural sustainability and productivity in this region is under serious threat due to climate change and the depletion of water resources. This is worsened by poor management practices, such as the overuse of chemical fertilizers, pesticides, overgrazing and monoculture farming. Recent climate change models indicate that European and Northern African regions will undergo extreme climatic events throughout the year, this will negatively impact crop yield and productivity. Summer droughts and heat waves periods will increase for most parts of Europe, as well as short intense rain events. Preserving and improving productive agricultural land in this region is vital, especially through the application of sustainable soil and crop management practices that promote soil fertility and water conservation; this will improve resilience to degradation and to extreme climatic events. ReCROP is a European project that aims to identify sustainable and resilient agricultural production systems in the Mediterranean region through the combined use of biotechnological tools, such as bioinoculants, and environmentally friendly agronomic practices. ReCROP will assess different agroecosystems with key local crops (i.e vineyards, maize and aromatic/medicinal plants) of the Mediterranean region under field conditions to help improve crop resilience, yield, water conservation and soil health under the current scenario of climate change. Soil organisms play a key role in ecosystem processes, leading to essential soil functions and are used as bioindicators of soil quality. Their monitoring is crucial to assess the impact of beneficial agricultural practices on soil functioning. One of the goals of ReCROP will be to evaluate the beneficial impact of different agricultural practices on the structural and functional soil diversity at different levels of the soil food web. The macrofauna and mesofauna (i.e springtails and mites) as well as microbial biomass, activity and biodiversity of soil microbial communities (bacteria, archaea, fungi) will be monitored with a special effort to produce a multitaxa index of soil biological quality. This work will contribute to identify which practices are beneficial for the biodiversity of Mediterranean agricultural soils, thus providing resistance and resilience, in terms of soil functioning and against soil disturbances.info:eu-repo/semantics/publishedVersio
Pion and Kaon Vector Form Factors
We develop a unitarity approach to consider the final state interaction
corrections to the tree level graphs calculated from Chiral Perturbation Theory
() allowing the inclusion of explicit resonance fields. The method is
discussed considering the coupled channel pion and kaon vector form factors.
These form factors are then matched with the one loop results. A very
good description of experimental data is accomplished for the vector form
factors and for the P-wave phase shifts up to
GeV, beyond which multiparticle states play a non negligible role. In
particular the low and resonance energy regions are discussed in detail and for
the former a comparison with one and two loop is made showing a
remarkable coincidence with the two loop results.Comment: 20 pages, 7 figs, to appear in Phys. Rev.
Evidence for Factorization in Three-body B --> D(*) K- K0 Decays
Motivated by recent experimental results, we use a factorization approach to
study the three-body B --> D(*) K- K0 decay modes. Two mechanisms are proposed
for kaon pair production: current-produced (from vacuum) and transition (from B
meson). The Bbar0 --> D(*)+ K- K0 decay is governed solely by the
current-produced mechanism. As the kaon pair can be produced only by the vector
current, the matrix element can be extracted from e+ e- --> K Kbar processes
via isospin relations. The decay rates obtained this way are in good agreement
with experiment. Both current-produced and transition processes contribute to
B- --> D(*)0 K- K0 decays. By using QCD counting rules and the measured B- -->
D(*)0 K- K0 decay rates, the measured decay spectra can be understood.Comment: 17 pages, 6 figure
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