Planning with Incomplete Information

Planning is a natural domain of application for frameworks of reasoning about actions and change. In this paper we study how one such framework, the Language E, can form the basis for planning under (possibly) incomplete information. We define two types of plans: weak and safe plans, and propose a planner, called the E-Planner, which is often able to extend an initial weak plan into a safe plan even though the (explicit) information available is incomplete, e.g. for cases where the initial state is not completely known. The E-Planner is based upon a reformulation of the Language E in argumentation terms and a natural proof theory resulting from the reformulation. It uses an extension of this proof theory by means of abduction for the generation of plans and adopts argumentation-based techniques for extending weak plans into safe plans. We provide representative examples illustrating the behaviour of the E-Planner, in particular for cases where the status of fluents is incompletely known.Comment: Proceedings of the 8th International Workshop on Non-Monotonic Reasoning, April 9-11, 2000, Breckenridge, Colorad

The lived experience of fibromyalgia in female patients, a phenomenological study

<p>Abstract</p> <p>Background</p> <p>Fibromyalgia is a chronic syndrome with no cure. A thorough understanding of the illness experience is therefore key in the palliative care of patients with this condition. In search for supportive treatments fibromyalgia patients often attend a chiropractor or other manual therapist. Knowledge of the meaning and reality of living with this condition to the patient could be considered essential to any health care practitioner playing a role in the management. This study aimed to gain a better understanding of the subjective experience of fibromyalgia, focusing on the personal, occupational and social impact of the condition on patients' lives. This included exploring the patients' views about the future.</p> <p>Methods</p> <p>This study employed descriptive phenomenology and adopted Husserl's concept of transcendental subjectivity or "bracketing". This qualitative study involved semi-structured interviews and was undertaken to obtain rich data that reflected the essence of the participants' experience. Participants consisted of six female volunteers, diagnosed with fibromyalgia by the University Hospital Gent, Belgium. Data were analysed using a thematic framework.</p> <p>Results</p> <p>Fibromyalgia pervaded all aspects of life. Four main themes arose from data analysis, namely; the impact of fibromyalgia on patients' occupational and personal life, the impact on their future and aspects of social interaction. Nearly all participants had stopped working, giving rise to feelings of uselessness and loss of identity. Leisure activities were also greatly affected. Fibromyalgia was said to alter family bonds, some of which were reinforced, others were broken. The diagnosis was seen as a relief, marking an end to a period of uncertainty. Participants reported ambivalence in interaction. Despite some positive encounters, frustration arising from perceived incomprehension dominated. Consequently patients preferred not to share their experiences.</p> <p>Conclusions</p> <p>The study revealed the negative impact of fibromyalgia on patients' lives as comprising of great complexity and individuality. Several implications for health care practitioners can be extrapolated, including the need of a more efficient diagnostic process and increased education about the fibromyalgia experience. Further studies are required to better clarify the multifaceted nature of living with the condition.</p

The size of the X-ray emitting region in SWIFT J2127.4+5654 via a broad line region cloud X-ray eclipse

We present results obtained from the time-resolved X-ray spectral analysis of the Narrow-Line-Seyfert 1 galaxy SWIFT J2127.4+5654 during a ~130 ks XMM-Newton observation. We reveal large spectral variations, especially during the first ~90 ks of the XMM-Newton exposure. The spectral variability can be attributed to a partial eclipse of the X-ray source by an intervening low-ionization/cold absorbing structure (cloud) with column density N_H = 2.0^{+0.2}_{-0.3}e22 cm^-2 which gradually covers and then uncovers the X-ray emitting region with covering fraction ranging from zero to ~43 per cent. Our analysis enables us to constrain the size, number density, and location of the absorbing cloud with good accuracy. We infer a cloud size (diameter) of $D_c < 1.5e13 cm, corresponding to a density of n_c > 1.5e9 cm^-3 at a distance of R_c > 4.3e16 cm from the central black hole. All of the inferred quantities concur to identify the absorbing structure with one single cloud associated with the broad line region of SWIFT J2127.4+5654. We are also able to constrain the X-ray emitting region size (diameter) to be D_s < 2.3e13 cm which, assuming the black hole mass estimated from single-epoch optical spectroscopy (1.5e7 M_sun), translates into D_s < 10.5 gravitational radii (r_g) with larger sizes (in r_g) being associated with smaller black hole masses, and viceversa. We also confirm the presence of a relativistically distorted reflection component off the inner accretion disc giving rise to a broad relativistic Fe K emission line and small soft excess (small because of the high Galactic column density), supporting the measurement of an intermediate black hole spin in SWIFT J2127.4+5654 that was obtained from a previous Suzaku observation.Comment: 8 pages, 7 figures, accepted for publication in MNRA

Distinguishing between dark-matter interactions with gravitational-wave detectors

Ground-based gravitational-wave interferometers could directly probe the existence of ultralight dark matter ($\mathcal{O}(10^{-14}-10^{-11})$ eV/$c^2$) that couples to standard-model particles in the detectors. Recently, many techniques have been developed to extract a variety of potential dark-matter signals from noisy gravitational-wave data; however, little effort has gone into ways to distinguish between types of dark matter that could directly interact with the interferometers. In this work, we employ the Wiener filter to follow-up candidate dark-matter interaction signals. The filter captures the stochastic nature of these signals, and, in simulations, successfully identifies which type of dark matter interacts with the interferometers. We apply the Wiener filter to outliers that remained in the LIGO/Virgo/KAGRA search for dark photons in data from the most recent observing (O3), and show that they are consistent with noise disturbances. Our proof-of-concept analysis demonstrates that the Wiener filter can be a powerful technique to confirm or deny the presence of dark-matter interaction signals in gravitational-wave data, and distinguish between scalar and vector dark-matter interactions.Comment: 10 pages, 8 figure

Re-examining the contested good: proceedings from a postgraduate workshop on good food

Following the 2017 postgraduate research workshop hosted by the SOAS Food Studies Centre, in collaboration with University of Warwick Food GRP, this article brings together nine research briefs written by various participants. Inspired by the workshop's provocative theme, “What Is Good Food?”, each author explores how food categories are shaped and negotiated in different contexts and across scales. In this multi-authored article, the question of “good” food is first presented as contingent upon nutritional, economic, political, ritual, or moral conditions. Each author then reveals how globally defined notions of food's goodness are often resisted on the ground by producers and consumers, beyond the notions of ethics or “alternative” food movements that have often been the emphasis of previous literature dealing with the topic of good food. Taken together, this article scrutinizes the effects of various hierarchies of power and invites readers to reassess why and how good food continues to be a contested category

The MODEST questions: challenges and future directions in stellar cluster research

We present a review of some of the current major challenges in stellar cluster research, including young clusters, globular clusters, and galactic nuclei. Topics considered include: primordial mass segregation and runaway mergers, expulsion of gas from clusters, the production of stellar exotica seen in some clusters (eg blue stragglers and extreme horizontal--branch stars), binary populations within clusters, the black--hole population within stellar clusters, the final parsec problem, stellar dynamics around a massive black hole, and stellar collisions. The Modest Questions posed here are the outcome of discussions which took place at the Modest-6A workshop held in Lund, Sweden, in December, 2005. Modest-6A was organised as part of the activities of the Modest Collaboration (see www.manybody.org for further details)Comment: 24 pages, no figures, accepted for publication in New Astronom