34 research outputs found
A review of diagnostic and functional imaging in headache
The neuroimaging of
headache patients has revolutionised
our understanding of the pathophysiology
of primary headaches and provided
unique insights into these syndromes.
Modern imaging studies
point, together with the clinical picture,
towards a central triggering
cause. The early functional imaging
work using positron emission
tomography shed light on the genesis
of some syndromes, and has
recently been refined, implying that
the observed activation in migraine
(brainstem) and in several trigeminal-autonomic headaches (hypothalamic
grey) is involved in the pain
process in either a permissive or
triggering manner rather than simply
as a response to first-division nociception
per se. Using the advanced
method of voxel-based morphometry,
it has been suggested that there
is a correlation between the brain
area activated specifically in acute
cluster headache — the posterior
hypothalamic grey matter — and an
increase in grey matter in the same
region. No structural changes have
been found for migraine and medication
overuse headache, whereas
patients with chronic tension-type
headache demonstrated a significant
grey matter decrease in regions
known to be involved in pain processing.
Modern neuroimaging thus
clearly suggests that most primary
headache syndromes are predominantly
driven from the brain, activating
the trigeminovascular reflex and
needing therapeutics that act on both
sides: centrally and peripherally
National identity predicts public health support during a global pandemic
Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = −0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.publishedVersio
Characterization of chemical sputtering using the mark II DiMES porous plug injector in attached and semi-detached divertor plasmas of DIII-D
An improved, self-contained gas injection system for the divertor material evaluation system (DIMES) on DIII-D has been employed for in situ study of chemical erosion in the tokamak divertor environment. To minimize perturbation to local plasma, the Mark II porous plug injector (PPI) releases methane through a porous graphite surface at the outer strike point at a rate precisely controlled by a micro-orifice flow restrictor to be approximately equal as that predicted for intrinsic chemical sputtering. Effective photon efficiencies resulting from CH4 are found to be 58 +/- 12 in an attached divertor (n(e) similar to 1.5 x 10(13)/cm(3), T-e similar to 25 eV, T-surf similar to 450 K), and 94 +/- 20 in a semi-detached cold divertor (n(e) similar to 6.0 x 10(13)/cm(3), T-e similar to 2-3 eV, T-surf similar to 350 K). These values are significantly more than previous measurements in similar plasma conditions, indicating the importance of the injection rate and local re-erosion for the integrity of this analysis. The contribution of chemical versus physical sputtering to the source of C+ at the target is assessed through simultaneous measurement of CII line, and CD plus CH-band emissions during release of CH4 from the Pill, then compared with that seen in intrinsic sputtering. (C) 2009 Elsevier B.V. All rights reserved