An electrochemical study of the corrosion processes of Ni-based glassy metals in aqueous solutions

The electrochemical behavior of amorphous Ni-Co alloys in carbonate/bicarbonate solutions was investigated using electrochemical impedance spectroscopy combined with voltammetry and stationary polarization techniques. The results indicate that the kinetics of the dissolution processes are dependent on the pH and ionic strength of the electrolyte. The composition of the glassy metal is an important factor in determining the kinetic parameters involved in the complex electrochemical behavior of these materials

Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic

Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{$6\times 10^{19}$eV}. The anisotropy was measured by the fraction of arrival directions that are less than $3.1^\circ$ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron $12^{\rm th}$ catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is $(38^{+7}_{-6})$, compared with $21$ expected for isotropic cosmic rays. This is down from the early estimate of $(69^{+11}_{-13})$. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201

The Second Step In The Construction Of A Stigma Scale Of Epilepsy

Rationale: The issue of stigmatization is one of the most common psychosocial problems faced by people with epilepsy. Purpose: A second step towards the development of a scale to measure epilepsy stigma. Method: We applied a closed questionnaire to 12 patients and 32 relatives from the Epilepsy Outpatient Clinic at the University Hospital of Campinas. Results: The results are grouped in three main domains: medical, social and personal areas. Medical: the subjects did not know exactly what epilepsy is or how it is caused; nonetheless they know how to treat it. Social: the most important areas that people with epilepsy are discriminated are at work and social relationships. Patients also complained about their lack of freedom and limits on recreation activities. Personal Area: subjects apparently have the same feelings and thoughts about epilepsy and seizures. Conclusion: This study analyzed the most common aspects presented in the questionnaire to assess epilepsy stigma for the Brazilian culture which are the base to the elaboration of a stigma scale of epilepsy.632 B395398Fernandes, P.T., Souza, E.A., Identification of family variables in parents' groups of children with epilepsy (2001) Arq Neuropsiquiatr, 59, pp. 854-858Li, L.M., Sander, J.W., National demonstration project on epilepsy in Brazil (2003) Arq Neuropsiquiatr, 61, pp. 153-156Leidy, N.K., Rentz, A.M., Grace, E.M., Evaluating health-related quality of life outcomes in clinical trials of antiepileptic drug therapy (2004) Epilepsia, 39, pp. 965-977Baker, G.A., Brooks, J., Buck, D., Jacoby, A., The stigma of epilepsy: A European perspective (2000) Epilepsia, 41, pp. 98-104Baker, G.A., Nashef, L., Van Hout, B.A., Current issues in the management of epilepsy: The impact of frequent seizures on cost of illness, quality of life, and mortality (1997) Epilepsia, 38 (SUPPL. 1), pp. S1-S8Baker, G.A., Jacoby, A., Chadwick, D.W., The associations of psychopathology in epilepsy: A community study (1996) Epilepsy Res, 25, pp. 29-39Jacoby, A., Felt versus enacted stigma: A concept revisited. Evidence from a study of people with epilepsy in remission (1994) Soc Sci Med, 38, pp. 269-274Placencia, M., Farmer, P.J., Jumbo, L., Sander, J.W., Shorvon, S.D., Levels of stigmatization of patients with previously untreated epilepsy in northern Ecuador (1995) Neuroepidemiology, 14, pp. 147-154Ratsepp, M., Oun, A., Haldre, S., Kaasik, A.E., Felt stigma and impact of epilepsy on employment status among Estonian people: Exploratory study (2000) Seizure, 9, pp. 394-401Scambler, G., Hopkins, A., Generating a model of epileptic stigma: The role of qualitative analysis (1990) Soc Sci Med, 30, pp. 1187-1194Ryan, R., Kempner, K., Emlen, A.C., The stigma of epilepsy as a self-concept (1980) Epilepsia, 21, pp. 433-444Fernandes, P.T., Salgado, P.C., Ala, N., Barbosa, F.D., Souza, E.A., Li, L.M., Stigma Scale of Epilepsy: Conceptual issues (2004) J Epilep Clin Neuropshysiology, 10, pp. 213-218McLin, W.M., De Boer, H.M., Public perceptions about epilepsy (1995) Epilepsia, 36, pp. 957-95

The Fluorescence Detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section

Search for First Harmonic Modulation in the Right Ascension Distribution of Cosmic Rays Detected at the Pierre Auger Observatory

We present the results of searches for dipolar-type anisotropies in different energy ranges above $2.5\times 10^{17}$ eV with the surface detector array of the Pierre Auger Observatory, reporting on both the phase and the amplitude measurements of the first harmonic modulation in the right-ascension distribution. Upper limits on the amplitudes are obtained, which provide the most stringent bounds at present, being below 2% at 99% $C.L.$ for EeV energies. We also compare our results to those of previous experiments as well as with some theoretical expectations.Comment: 28 pages, 11 figure