In-depth studies of the NGC 253 ULXs with XMM-Newton: remarkable variability in ULX1, and evidence for extended coronae

We examined the variability of three ultra-luminous X-ray sources (ULXs) in the 2003, 110 ks XMM-Newton observation of NGC253. Remarkably, we discovered ULX1 to be three times more variable than ULX2 in the 0.3--10 keV band, even though ULX2 is brighter. Indeed, ULX1 exhibits a power density spectrum that is consistent with the canonical high state or very high/steep power law state, but not the canonical low state. The 0.3--10 keV emission of ULX1 is predominantly non-thermal, and may be related to the very high state. We also fitted the ULX spectra with disc blackbody, slim disc and convolution Comptonization (SIMPL x DISKBB) models. The brightest ULX spectra are usually described by a two emission components (disc blackbody + Comptonized component); however, the SIMPL model results in a single emission component, and may help determine whether the well known soft excess is a feature of ULX spectra or an artifact of the two-component model. The SIMPL models were rejected for ULX3 (and also for the black hole + Wolf-Rayet binary IC10 X-1); hence, we infer that the observed soft-excesses are genuine features of ULX emission spectra. We use an extended corona scenario to explain the soft excess seen in all the highest quality ULX spectra, and provide a mechanism for stellar mass black holes to exhibit super-Eddington luminosities while remaining locally sub-Eddington.Comment: Accepted for publication in MNRAS. 7 pages, 5 figure

Eliciting Behavior From Interactive Narratives: Isolating the Role of Agency in Connecting With and Modeling Characters

A key component differentiating interactive storytelling from non-interactive media is agency, or control over character choices. A series of experiments show that providing agency over a character increased the user-character connection, which then increased engagement in a character-consistent charitable act. Findings were observed in technologically simple online narratives that controlled for navigation/controller differences, graphics, sounds, lengthy play, and avatar customization. Effects emerged even though users did not practice these acts by making their character behave charitably. Findings were robust across happy and unfortunate endings and across first-, second-, and third-person narrative perspectives. Findings suggest promise for developing inexpensive ‘‘storygames’’ to encourage supportive behaviors

Researching Across Two Cultures: Shifting Positionality

Embodied and creative research methods provoke honesty, emotion, and vulnerability in participants, which add to the richness of the stories they tell and are willing to share. The positionality of the researcher is less of “interviewer” and more “co-producer” or participant in a dialogue. Visual and creative approaches invite participants to share in ways in which they are not able or willing through words alone. The data and outputs they produce, with film, art, or objects, can in turn affect those who see it more than written text and need to be analysed and disseminated along with more traditional transcripts, articles, and presentations. In the context of investigating sensitive issues such as those around embodied identity, these methods, which use embodied methods to explore embodied research questions, may feel the most appropriate. These approaches lie along the boundary of therapy and research, asking much of researchers who are unlikely to have received therapeutic training or ongoing support. Due to this deficit, the researched may find that their experience is not held or contained in a way that the content would demand. Similarly, the data themselves lie on the boundary of art and research, in that they can be seen as more than a tool to facilitate reflection, but as artifacts in their own right. What are the implications in this scenario? Where should we position ourselves and our work along these boundaries? Who holds the space for the researcher and the researched if both are made vulnerable

A Multi-coloured survey of NGC 253 with XMM-Newton

There is a large body of work that has used the excellent Chandra observations of nearby galaxies with neglible low mass X-ray binary (LMXB) populations. This has culminated in a ``Universal'' X-ray luminosity function (XLF) for high mass X-ray binaries (HMXBs). However, a number of methods have been used to convert from source intensities to luminosities when creating these XLFs. We have taken advantage of the XMM-Newton observations of the nearby starbursting spiral galaxy NGC 253 to test some of these methods. We find the luminosities derived from these various methods to vary by a factor of $\sim$3. We also find the most influential factor in the conversion from intensity to luminosity to be the absorption. We therefore conclude that a more consistent approach is required for determining the true Universal XLF for HMXBs. Ideally, this would involve individual spectral fitting of each X-ray source. Certainly, the line-of-sight absorption should be determined from the observations rather than assuming Galactic absorption. We find the best approach for obtaining an XLF from low-count data to be the splitting of the X-ray sources into two or more intensity intervals, and obtaining a conversion from intensity to flux for each group from spectral modelling of the summed spectrum of that group.Comment: To appear in the proceedings of "X-rays from Nearby Galaxies", 4-7 Septembeer 2007, 4 page

Strategies used in the pursuit of achievability during goal setting in rehabilitation

We used conversation analysis of six audio- and video-recorded goal setting meetings that were attended by patients and their respective treating team to explore and describe the interaction of participants during interdisciplinary goal setting, and to identify the strategies used to agree goals. The health care professionals involved in the six sessions included four physiotherapists, four occupational therapists, four nurses, one speech and language therapist, and one neuropsychologist. The participants included 3 patients with multiple sclerosis, 2 patients with spinal cord lesions, and 1 patient with stroke from an inpatient neurological rehabilitation unit. Detailed analysis revealed how the treating team shaped the meetings. The most notable finding was that there was rarely a straightforward translation of patient wishes into agreed-on written goals, with the treating team leading goal modification so that goals were achievable. Despite professional dominance, patients also influenced the course of the interaction, particularly when offering resistance to goals proposed by the treating team