20,371 research outputs found
Complex networks in brain electrical activity
We analyze the complex networks associated with brain electrical activity.
Multichannel EEG measurements are first processed to obtain 3D voxel
activations using the tomographic algorithm LORETA. Then, the correlation of
the current intensity activation between voxel pairs is computed to produce a
voxel cross-correlation coefficient matrix. Using several correlation
thresholds, the cross-correlation matrix is then transformed into a network
connectivity matrix and analyzed. To study a specific example, we selected data
from an earlier experiment focusing on the MMN brain wave. The resulting
analysis highlights significant differences between the spatial activations
associated with Standard and Deviant tones, with interesting physiological
implications. When compared to random data networks, physiological networks are
more connected, with longer links and shorter path lengths. Furthermore, as
compared to the Deviant case, Standard data networks are more connected, with
longer links and shorter path lengths--i.e., with a stronger ``small worlds''
character. The comparison between both networks shows that areas known to be
activated in the MMN wave are connected. In particular, the analysis supports
the idea that supra-temporal and inferior frontal data work together in the
processing of the differences between sounds by highlighting an increased
connectivity in the response to a novel sound.Comment: 22 pages, 5 figures. Starlab preprint. This version is an attempt to
include better figures (no content change
Modelling the Io-related DAM emission by modifying the beaming angle
The Io-Jupiter interaction generates strong decametric radio emissions (DAM), which appear as arcs in the time-frequency plane. These emissions are beamed at an angle from the magnetic field lines, which may vary with frequency and longitude amongst other properties. Empirical models of this beaming angle describe the shape of the DAM arcs and offer insight into the emission mechanism for DAM. Several studies have investigated the variation in the emission beaming angle. The studies span a range of frequencies which depend on the observational means (spacecraft, ground-based radio telescopes) used to obtain data. Subsequently, because of the varying assumptions made (e.g. relativistic vs. non-relativistic electrons for the wave polarization), methods used (e.g. prescribing a beaming angle function vs. determining a beaming angle function from observational geometry) and frequency ranges observed, different results have been found in each study. In the present paper, we model the shape of the emission with an empirical beaming angle function and adjust the parameters to best fit the emission arcs. However, our model builds on previous models by taking into account the location of Io in the Jovian magnetic field. We also look at a broader frequency range than many of the intermediate studies. We find that a simple empirical beaming angle function describes the shape of the A, B, and D arcs and that the beaming angle function must decrease at high and low frequencies. We then propose a simple explanation for the beaming angle profile, deduced from cyclotron maser theory
Proceedings of the inaugural International Summit for Medical Nutrition Education and Research
© 2016 The Royal Society for Public Health Medical Nutrition Education (MNE) has been identified as an area with potential public health impact. Despite countries having distinctive education systems, barriers and facilitators to effective MNE are consistent across borders, demanding a common platform to initiate global programmes. A shared approach to supporting greater MNE is ideal to support countries to work together. In an effort to initiate this process, the Need for Nutrition Education/Innovation Programme group, in association with their strategic partners, hosted the inaugural International Summit on Medical Nutrition Education and Research on August 8, 2015 in Cambridge, UK. Speakers from the UK, the USA, Canada, Australia, New Zealand, Italy, and India provided insights into their respective countries including their education systems, inherent challenges, and potential solutions across two main themes: (1) Medical Nutrition Education, focused on best practice examples in competencies and assessment; and (2) Medical Nutrition Research, discussing how to translate nutrition research into education opportunities. The Summit identified shared needs across regions, showcased examples of transferrable strategies and identified opportunities for collaboration in nutrition education for healthcare (including medical) professionals. These proceedings highlight the key messages presented at the Summit and showcase opportunities for working together towards a common goal of improvement in MNE to improve public health at large
Can altering the structure of financial support payments aid work retention amongst lone parents? Qualitative evaluation of the In Work Retention Pilot
Wage supplementations in the form of temporary ‘in-work credits’ have been introduced in recent years for a number of claimant groups entering work, to encourage enhanced work entry and retention rates. For lone parents, the In Work Credit was piloted from April 2004 and then rolled out nationally in April 2008. It is a wage supplement paid at £40 a week (£60 in London) for 12 months to eligible lone parents moving in to work. From July 2008 to June 2010, a variant on this, the In Work Retention Pilot (IWRP), was trialled in two Jobcentre Plus districts. The IWRP was intended to test the effectiveness of using In Work Credit payments as an aid to job retention and progression, by changing the payment structure of the credits and offering additional advisory support on retention and advancement.
This report presents findings from a qualitative evaluation of the IWRP, examining the delivery of the pilot and the views of lone parents and Jobcentre Plus staff on: the distinctive IWRP payment structure; the retention and progression challenges facing lone parents and the support received; and whether and how the IWRP made a difference to work behaviour and decisions. The study is based on interviews, focus groups and observations with Jobcentre Plus delivery staff and participating lone parents
Review of design and operational characteristics of the 0.3-meter transonic cryogenic tunnel
The past 6 years of operation with the NASA Langley 0.3 m transonic cryogenic tunnel (TCT) show that there are no insurmountable problems associated with cryogenic testing with gaseous nitrogen at transonic Mach numbers. The fundamentals of the concept were validated both analytically and experimentally and the 0.3 m TCT, with its unique Reynolds number capability, was used for a wide variety of aerodynamic tests. Techniques regarding real-gas effects were developed and cryogenic tunnel conditions can be set and maintained accurately. Cryogenic cooling by injecting liquid nitrogen directly into the tunnel circuit imposes no problems with temperature distribution or dynamic response characteristics. Experience with the 0.3 m TCT, indicates that there is a significant learning process associated with cryogenic, high Reynolds number testing. Many of the questions have already been answered; however, factors such as tunnel control, run logic, economics, instrumentation, and model technology present many new and challenging problems
Spectroscopic study of unique line broadening and inversion in low-pressure microwave generated water plasmas
It was demonstrated that low pressure (~0.2 Torr) water vapor plasmas
generated in a 10 mm inner diameter quartz tube with an Evenson microwave
cavity show at least two features which are not explained by conventional
plasma models. First, significant (> 0.25 nm) hydrogen Balmer_ line broadening,
of constant width, up to 5 cm from the microwave coupler was recorded. Only
hydrogen, and not oxygen, showed significant line broadening. This feature,
observed previously in hydrogen-containing mixed gas plasmas generated with
high voltage dc and rf discharges was explained by some researchers to result
from acceleration of hydrogen ions near the cathode. This explanation cannot
apply to the line broadening observed in the (electrodeless) microwave plasmas
generated in this work, particularly at distances as great as 5 cm from the
microwave coupler. Second, inversion of the line intensities of both the Lyman
and Balmer series, again, at distances up to 5 cm from the coupler, were
observed. The line inversion suggests the existence of a hitherto unknown
source of pumping of the optical power in plasmas. Finally, it is notable that
other aspects of the plasma including the OH* rotational temperature and low
electron concentrations are quite typical of plasmas of this type.Comment: 27 pages, 7 figure
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