EEGgui: a program used to detect electroencephalogram anomalies after traumatic brain injury

BACKGROUND: Identifying and quantifying pathological changes in brain electrical activity is important for investigations of brain injury and neurological disease. An example is the development of epilepsy, a secondary consequence of traumatic brain injury. While certain epileptiform events can be identified visually from electroencephalographic (EEG) or electrocorticographic (ECoG) records, quantification of these pathological events has proved to be more difficult. In this study we developed MATLAB-based software that would assist detection of pathological brain electrical activity following traumatic brain injury (TBI) and present our MATLAB code used for the analysis of the ECoG. METHODS: Software was developed using MATLAB(™) and features of the open access EEGLAB. EEGgui is a graphical user interface in the MATLAB programming platform that allows scientists who are not proficient in computer programming to perform a number of elaborate analyses on ECoG signals. The different analyses include Power Spectral Density (PSD), Short Time Fourier analysis and Spectral Entropy (SE). ECoG records used for demonstration of this software were derived from rats that had undergone traumatic brain injury one year earlier. RESULTS: The software provided in this report provides a graphical user interface for displaying ECoG activity and calculating normalized power density using fast fourier transform of the major brain wave frequencies (Delta, Theta, Alpha, Beta1, Beta2 and Gamma). The software further detects events in which power density for these frequency bands exceeds normal ECoG by more than 4 standard deviations. We found that epileptic events could be identified and distinguished from a variety of ECoG phenomena associated with normal changes in behavior. We further found that analysis of spectral entropy was less effective in distinguishing epileptic from normal changes in ECoG activity. CONCLUSION: The software presented here was a successful modification of EEGLAB in the Matlab environment that allows detection of epileptiform ECoG signals in animals after TBI. The code allows import of large EEG or ECoG data records as standard text files and uses fast fourier transform as a basis for detection of abnormal events. The software can also be used to monitor injury-induced changes in spectral entropy if required. We hope that the software will be useful for other investigators in the field of traumatic brain injury and will stimulate future advances of quantitative analysis of brain electrical activity after neurological injury or disease

A Discipline-Spanning Overview of Action Research and Its Implications for Technology and Innovation Management

The iterative and learning character of action research is particularly beneficial for exploring complex socio-technical problems in technology and innovation management (TIM). In this respect, action research allows both rigorous and relevant research due to parallel solving of real-world problems, capability building, and gaining scientific insights. However, the use of action research within TIM research is surprisingly limited. Action research also is not a homogeneous research methodology since each research discipline, such as education and organizational science, has its own action research streams, which are often only loosely linked. A systematic overview of those action research traditions and specific best practices is still missing, which complicates a systematic transfer and use of action research in TIM. This article addresses this essential gap by building a cross-disciplinary overview of action research streams based on a bibliometric analysis using Scopus. The analysis includes relevant disciplines with action research traditions, their development over time, and the most influential journals, authors, institutions, and countries. Along with this discipline-spanning analysis, the article investigates particular TIM benefits and challenges of action research. The two key contributions of this article are: 1) a discipline-spanning overview of action research and its evolution and 2) an analysis of its implications for TIM research. These contributions build the basis for strengthening the use of action research in TIM. In the medium-term, action research has the capacity to link academia and industry more closely and, in doing so, assists important endeavours of translating more of our research outcomes into practice

Equation of state of hadronic matter with dibaryons in an effective quark model

The equation of state of symmetric nuclear matter with the inclusion of non-strange dibaryons is studied. We pay special attention to the existence of a dibaryon condensate at zero temperature. These calculations have been performed in an extended quark-meson coupling model with density-dependent parameters, which takes into account the finite size of nucleons and dibaryons. A first-order phase-transition to pure dibaryon matter has been found. The corresponding critical density is strongly dependent on the value of the dibaryon mass. The density behavior of the nucleon and dibaryon effective masses and confining volumes have also been discussed.Comment: 9 pages, LaTex, 3 Postscript figures, a misprint correcte

Parametrization of nuclear parton distributions

Optimum nuclear parton distributions are obtained by analyzing available experimental data on electron and muon deep inelastic scattering (DIS). The distributions are given at Q^2=1 GeV^2 with a number of parameters, which are determined by a chi^2 analysis of the data. Valence-quark distributions are relatively well determined at medium x, but they are slightly dependent on the assumed parametrization form particularly at small x. Although antiquark distributions are shadowed at small x, their behavior is not obvious at medium x from the F_2 data. The gluon distributions could not be restricted well by the inclusive DIS data; however, the analysis tends to support the gluon shadowing at small x. We provide analytical expressions and computer subroutines for calculating the nuclear parton distributions, so that other researchers could use them for applications to other high-energy nuclear reactions.Comment: 1+11 pages, LaTeX, amsmath.sty, wrapfig.sty, graphicx.sty, ias.cls, ias.sty, pramana.sty, pmana10.sty, pbib.sty, times.sty, 9 eps figures. Invited talk given at the International Symposium on Nuclear Physics, Mumbai, India, Dec. 18-22, 2000, to be published in proceedings. Complete postscript file is available at http://www-hs.phys.saga-u.ac.jp Email: [email protected], [email protected], [email protected]

The semi-classical approach to the exclusive electron scattering

The semiclassical approach, successfully applied in the past to the inelastic, inclusive electron scattering off nuclei, is extended to the treatment of exclusive processes. The final states interaction is accounted for in the mean field approximation, respecting the Pauli principle. The impact on the exclusive cross section of the shape of the potential binding the nucleons into the nucleus and of the distortion of the outgoing nucleon wave are explored. The exclusive scattering is found to be quite sensitive to the mean field final states interaction, unlike the inclusive one. Indeed we verify that the latter is not affected, as implied by unitarity, by the distortion of the outgoing nucleon wave except for the effect of relativity, which is modest in the range of momenta up to about 500 MeV/c. Furthermore, depending upon the correlations between the directions of the outgoing and of the initial nucleon, the exclusive cross-section turns out to be remarkably sensitive to the shape of the potential binding the nucleons. These correlations also critically affect the domain in the missing energy-- missing momentum plane where the exclusive process occurs.Comment: 39 pages, latex, including 9 figures (fig.ps

Using Electron Scattering Superscaling to predict Charge-changing Neutrino Cross Sections in Nuclei

Superscaling analyses of few-GeV inclusive electron scattering from nuclei are extended to include not only quasielastic processes, but now also into the region where $\Delta$-excitation dominates. It is shown that, with reasonable assumptions about the basic nuclear scaling function extracted from data and information from other studies of the relative roles played by correlation and MEC effects, the residual strength in the resonance region can be accounted for through an extended scaling analysis. One observes scaling upon assuming that the elementary cross section by which one divides the residual to obtain a new scaling function is dominated by the $N\to\Delta$ transition and employing a new scaling variable which is suited to the resonance region. This yields a good representation of the electromagnetic response in both the quasielastic and $\Delta$ regions. The scaling approach is then inverted and predictions are made for charge-changing neutrino reactions at energies of a few GeV, with focus placed on nuclei which are relevant for neutrino oscillation measurements. For this a relativistic treatment of the required weak interaction vector and axial-vector currents for both quasielastic and $\Delta$-excitation processes is presented.Comment: 42 pages, 9 figures, accepted for publication in Physical Review

Nuclear corrections of parton distribution functions

We report global analysis results of experimental data for nuclear structure-function ratios F_2^A/F_2^{A'} and proton-nucleus Drell-Yan cross-section ratios sigma_{DY}^{pA}/sigma_{DY}^{pA'} in order to determine optimum parton distribution functions (PDFs) in nuclei. An important point of this analysis is to show uncertainties of the distributions by the Hessian method. The results indicate that the uncertainties are large for gluon distributions in the whole x region and for antiquark distributions at x>0.2. We provide a code for calculating any nuclear PDFs at given x and Q^2 for general users. They can be used for calculating high-energy nuclear reactions including neutrino-nucleus interactions, which are discussed at this workshop.Comment: 1+6 pages, LaTeX, 10 eps files, espcrc2.sty, to be published in Nucl. Phys. B Supplements, Proceedings of the Third International Workshop on Neutrino-Nucleus Interactions in the Few GeV Region (NuInt04), Gran Sasso, Italy, March 17-21, 2004. Nuclear PDF library is available at http://hs.phys.saga-u.ac.jp/nuclp.htm

The frequency and properties of young tidal dwarf galaxies in nearby gas-rich groups

We present high-resolution Giant Metrewave Radio Telescope (GMRT) HI observations and deep Canada-France-Hawaii Telescope (CFHT) optical imaging of two galaxy groups: NGC 4725/47 and NGC 3166/9. These data are part of a multi-wavelength unbiased survey of the gas-rich dwarf galaxy populations in three nearby interacting galaxy groups. The NGC 4725/47 group hosts two tidal knots and one dIrr. Both tidal knots are located within a prominent HI tidal tail, appear to have sufficient mass (M_gas~10^8 M_sol) to evolve into long-lived tidal dwarf galaxies (TDGs) and are fairly young in age. The NGC 3166/9 group contains a TDG candidate, AGC 208457, at least three dIrrs and four HI knots. Deep CFHT imaging confirms that the optical component of AGC 208457 is bluer -- with a 0.28 mag g-r colour -- and a few Gyr younger than its purported parent galaxies. Combining the results for these groups with those from the NGC 871/6/7 group reported earlier, we find that the HI properties, estimated stellar ages and baryonic content of the gas-rich dwarfs clearly distinguish tidal features from their classical counterparts. We optimistically identify four potentially long-lived tidal objects associated to three separate pairs of interacting galaxies, implying that TDGs are not readily produced during interaction events as suggested by some recent simulations. The tidal objects examined in this survey also appear to have a wider variety of properties than TDGs of similar mass formed in current simulations of interacting galaxies, which could be the result of pre- or post-formation environmental influences.Comment: 18 pages, 14 figures, accepted for publication in MNRA