Absolute single and multiple charge exchange cross sections for highly charged C, O, and Ne ions on H2O, CO, and CO2

Reported herein are measured absolute single, double, and triple charge exchange (CE) cross sections for the highly charged ions (HCIs) Cq+ (q=5,6), Oq+ (q=6,7,8), and Neq+ (q=7,8) colliding with the molecular species H2O, CO, and CO2. Present data can be applied to interpreting observations of x-ray emissions from comets as they interact with the solar wind. As such, the ion impact energies of 7.0q keV (1.62–3.06 keV/amu) are representative of the fast solar wind, and data at 1.5q keV for O6+ (0.56 keV/amu) on CO and CO2 and 3.5q keV for O5+ (1.09 keV/amu) on CO provide checks of the energy dependence of the cross sections at intermediate and typical slow solar wind velocities. The HCIs are generated within a 14 GHz electron cyclotron resonance ion source. Absolute CE measurements are made using a retarding potential energy analyzer, with measurement of the target gas cell pressure and incident and final ion currents. Trends in the cross sections are discussed in light of the classical overbarrier model (OBM), extended OBM, and with recent results of the classical trajectory Monte Carlo theory.

Channel characterization for single- and multiple-antenna wearable systems used for indoor body-to-body communications

In this paper, an analysis of radio channel characteristics for single- and multiple-antenna bodyworn systems for use in body-to-body communications is presented. The work was based on an extensive measurement campaign conducted at 2.45 GHz representative of an indoor sweep and search scenario for fire and rescue personnel. Using maximum-likelihood estimation in conjunction with the Akaike information criterion (AIC), five candidate probability distributions were investigated and from these the kappa - mu distribution was found to best describe small-scale fading observed in the body-to-body channels. Additional channel parameters such as autocorrelation and the cross-correlation coefficient between fading signal envelopes were also analyzed. Low cross correlation and small differences in mean signal levels between potential dual-branch diversity receivers suggested that the prospect of successfully implementing diversity in this type application is extremely good. Moreover, using selection combination, maximal ratio, and equal gain combining, up to 8.69-dB diversity gain can be made available when four spatially separated antennas are used at the receiver. Additional improvements in the combined envelopes through lower level crossing rates and fade durations at low signal levels were also observed.

Living with children diagnosed with Autism Spectrum Disorder: Parental and professional views

The number of children diagnosed with an autistic spectrum disorder (ASD) is rising and is now thought to be as high as 1:100. While the debate about best treatment continues, the effects of having a child diagnosed with ASD on family life remain relatively unexplored. This article, by Karola Dillenburger of Queens University Belfast, Mickey Keenan of the University of Ulster, Alvin Doherty from the Health Service Executive Western Region, Tony Byrne of Parents’ Education as Autism Therapists (PEAT) and Stephen Gallagher of the University of Ulster, sets out to adjust that balance. Drawing upon data from a comprehensive study of parental needs, these authors argue that parental and professional views do not always concur; that families make extraordinary sacrifices; that siblings are affected; and that parents are under tremendous stress. Parents argue that educational and social service supports are not efficient and that they are forced to rely largely on support from within the family or from friends. In particular, some important differences between parental and professional perceptions became apparent in relation to interventions based on Applied Behaviour Analysis (ABA). The authors of this article propose that these differences need to be taken seriously by teachers and other professionals as well as by policy-makers.

Stigma and multiple social comparisons in people with schizophrenia

This paper investigates social comparisons in people with schizophrenia. Stigma theories often suggest that people with stigmatized conditions face a chronic threat to self-esteem and that they respond to this in a variety of ways, one of which is by using ingroup downward comparisons. We analysed the spontaneous social comparisons used by, participants in semi-structured interviews. A wide range of comparison dimensions, target others, and groupings were used, most of which did not represent a category of people with schizophrenia in more negative terms than those without the illness. Participants presented themselves positively, referring to downward and lateral comparisons more often than upward comparisons. In addition, although downward comparisons did refer to people with schizophrenia, they were more likely to refer to others who did not have schizophrenia, and to dimensions which were not related to mental illness. It is suggested that investigations of the relations between stigma and self need to take account of the multiple identities and dimensions of comparisons available to people for construing themselves and the social context. Copyright (C) 2001 John Wiley & Sons, Ltd.

MEASUREMENT AND CALCULATION OF ABSOLUTE SINGLE AND MULTIPLE CHARGE EXCHANGE CROSS SECTIONS FOR Feq+ IONS IMPACTING H2O

Charge exchange (CE) plays a fundamental role in the collisions of solar- and stellar-wind ions with lunar and planetary exospheres, comets, and circumstellar clouds. Reported herein are absolute cross sections for single, double, triple, and quadruple CE of Feq+ (q = 5-13) ions with H2O at a collision energy of 7q keV. One measured value of the pentuple CE is also given for Fe9+ ions. An electron cyclotron resonance ion source is used to provide currents of the highly charged Fe ions. Absolute data are derived from knowledge of the target gas pressure, target path length, and incident and charge-exchanged ion currents. Experimental cross sections are compared with new results of the n-electron classical trajectory Monte Carlo approximation. The radiative and non-radiative cascades following electron transfers are approximated using scaled hydrogenic transition probabilities and scaled Auger rates. Also given are estimates of cross sections for single capture, and multiple capture followed by autoionization, as derived from the extended overbarrier model. These estimates are based on new theoretical calculations of the vertical ionization potentials of H2O up to H2O10+.