On the structure of Clifford quantum cellular automata

We study reversible quantum cellular automata with the restriction that these are also Clifford operations. This means that tensor products of Pauli operators (or discrete Weyl operators) are mapped to tensor products of Pauli operators. Therefore Clifford quantum cellular automata are induced by symplectic cellular automata in phase space. We characterize these symplectic cellular automata and find that all possible local rules must be, up to some global shift, reflection invariant with respect to the origin. In the one dimensional case we also find that every uniquely determined and translationally invariant stabilizer state can be prepared from a product state by a single Clifford cellular automaton timestep, thereby characterizing these class of stabilizer states, and we show that all 1D Clifford quantum cellular automata are generated by a few elementary operations. We also show that the correspondence between translationally invariant stabilizer states and translationally invariant Clifford operations holds for periodic boundary conditions.Comment: 28 pages, 2 figures, LaTe

Becoming and staying physically active in adolescents with cerebral palsy: protocol of a qualitative study of facilitators and barriers to physical activity

<p>Abstract</p> <p>Background</p> <p>Adolescents with cerebral palsy (CP) show a reduced physical activity (PA). Currently there are no interventions for adolescents with CP in this critical life phase that optimise and maintain the individuals' physical activity in the long term. To develop such a program it is important to fully understand the factors that influence physical activity behaviours in adolescents with CP. The aim of this study is to explore what makes it easy or hard for adolescents with CP to be and to become physically active.</p> <p>Methods/Design</p> <p>A qualitative research method is chosen to allow adolescents to voice their own opinion. Because we will investigate the lived experiences this study has a phenomenological approach. Thirty ambulatory and non-ambulatory adolescents (aged 10-18 years) with CP, classified as level I to IV on the Gross Motor Function Classification System and 30 parents of adolescents with CP will be invited to participate in one of the 6 focus groups or an individual interview. Therapists from all Children's Treatment Centres in Ontario, Canada, will be asked to fill in a survey. Focus groups will be audio- and videotaped and will approximately take 1.5 hours. The focus groups will be conducted by a facilitator and an assistant. In preparation of the focus groups, participants will fill in a demographic form with additional questions on physical activity. The information gathered from these questions and recent research on barriers and facilitators to physical activity will be used as a starting point for the content of the focus groups. Recordings of the focus groups will be transcribed and a content analysis approach will be used to code the transcripts. A preliminary summary of the coded data will be shared with the participants before themes will be refined.</p> <p>Discussion</p> <p>This study will help us gain insight and understanding of the participants' experiences and perspectives in PA, which can be of great importance when planning programs aimed at helping them to stay or to become physically active.</p

Software Engineering: CSC 324

Software Engineering: CSC 324, supplementary examination November 2011

Human Computer Interaction: CSC 522

Human Computer Interaction: CSC 522, supplementary examination January 2012

Simultaneous Visualization of Enzymatic Activity in the Cytoplasm and at Polyphosphate Inclusions in Beggiatoa sp. Strain 35Flor Incubated with 18O-Labeled Water

Microbial organisms exert a large influence on the environment as they directly affect the turnover of essential elements. This is particularly true for polyphosphate-accumulating large sulfur bacteria, which can either accumulate phosphate as polyphosphate or degrade it and release phosphate into the environment, depending on environmental conditions. This study presents a new approach to simultaneously visualize general metabolic activity and enzymatic activity at polyphosphate granules by incubation with 18O-labeled water as the only stable isotope tracer. For this purpose, the well-studied Beggiatoa sp. strain 35Flor was used as a model organism and was exposed to different stress regimes. General metabolic activity was strongly impaired during high-stress regimes. In contrast, intense intracellular polyP cycling was not restricted to favorable or stressful conditions, highlighting the importance of polyP for general cell physiology, especially during hostile conditions. The nanoSIMS approach adds a new tool to study microorganisms involved in phosphorus cycling in the environment together with the identification of general metabolic activity.Here we report on a new nanoscale secondary ion mass spectrometry (nanoSIMS) approach based on enzyme-mediated oxygen isotope exchange, which combines the visualization of general metabolic activity in the cytoplasm with insights into the activity of enzymes related to polyphosphate (polyP) inclusions. The polyP-accumulating strain of the large sulfur bacterium Beggiatoa was used as a model organism. Beggiatoa cultures were grown under oxic and anoxic conditions when exposed to either low- or high-sulfide conditions, which are known to influence polyP metabolism in this strain. Subsequent incubation with 18O-labeled water led to high 18O enrichments above the natural background in the cytoplasm and polyP granules derived from enzymatically mediated oxygen isotope exchange. The relative importance of polyP under the different sulfide regimes became evident by an apparent continued metabolic activity at polyP inclusions under stressfully high sulfide concentrations, in contrast to a decreased general metabolic activity in the cytoplasm. This finding confirms the role of polyP as a critical component in bacterial stress response and maintenance of a survival metabolism

Review of combined isotopic and optical nanoscopy.

Investigating the detailed substructure of the cell is beyond the ability of conventional optical microscopy. Electron microscopy, therefore, has been the only option for such studies for several decades. The recent implementation of several super-resolution optical microscopy techniques has rendered the investigation of cellular substructure easier and more efficient. Nevertheless, optical microscopy only provides an image of the present structure of the cell, without any information on its long-temporal changes. These can be investigated by combining super-resolution optics with a nonoptical imaging technique, nanoscale secondary ion mass spectrometry, which investigates the isotopic composition of the samples. The resulting technique, combined isotopic and optical nanoscopy, enables the investigation of both the structure and the "history" of the cellular elements. The age and the turnover of cellular organelles can be read by isotopic imaging, while the structure can be analyzed by optical (fluorescence) approaches. We present these technologies, and we discuss their implementation for the study of biological samples. We conclude that, albeit complex, this type of technology is reliable enough for mass application to cell biology.peerReviewe

Information Asymmetry in Hospitals: Evidence of the Lack of Cost Awareness in Clinicians

BACKGROUND: Information asymmetries and the agency relationship are two defining features of the healthcare system. These market failures are often used as a rationale for government intervention. Many countries have government financing and provision of healthcare in order to correct for this, while health technology agencies also exist to improve efficiency. However, informational asymmetries and the resulting principal-agent problem still persist, and one example is the lack of cost awareness amongst clinicians. This study explores the cost awareness of clinicians across different settings. METHODS: We targeted four clinical cohorts: medical students, Senior House Officers/Interns, Mid-grade Senior Registrar/Residents, and Consultant/Attending Physicians, in six hospitals in the United Kingdom, the United States, Australia, New Zealand and Spain. The survey asked respondents to report the cost (as they recalled) of different types of scans, visits, medications and tests. Our analysis focused on the differential between the perceived/recalled cost and the actual cost. We explored variation across speciality, country and other potential confounders. Cost-awareness levels were estimated based on the cost estimates within 25% of the actual cost. RESULTS: We received 705 complete responses from six sites across five countries. Our analysis found that respondents often overestimated the cost of common tests while underestimating high-cost tests. The mean cost-awareness levels varied between 4 and 23% for different items. Respondents acknowledged that they did not feel they had received adequate training in cost awareness. DISCUSSION: The current financial climate means that cost awareness and the appropriate use of scarce healthcare resources is more paramount than perhaps ever before. Much of the focus of health economics research is on high-cost innovative technologies, yet there is considerable waste in the system with respect to overtreatment and overdiagnosis. Common reasons put forward for this include defensive medicine, poor education, clinical uncertainty and the institution of protocols. CONCLUSION: Given the role of clinicians in the healthcare system, as agents both for patients and for providers, more needs to be done to remove informational asymmetries and improve clinician cost awareness

Parents' actions, challenges, and needs while enabling participation of children with a physical disability: a scoping review

Contains fulltext : 108967.pdf (publisher's version ) (Open Access)ABSTRACT: BACKGROUND: Pediatric rehabilitation considers Family-centered service (FCS) as a way to increase participation of children with a physical disability in daily life. An important principal is that parents greatly contribute to their child's participation at school, at home, and in the community. However, it is unclear what kind of information is available from literature about what parents actually do to support their child's participation and what problems and needs they experience? Hence, the aim of this study was to provide an overview of the actions, challenges, and needs of parents in enabling participation of their child with a physical disability that is neurological and non-progressive in nature. METHODS: Scoping review with extensive literature search (September 2011) and a thematic analysis to synthesize findings. RESULTS: Fourteen relevant articles revealed two major themes: 'parents enable and support performance of meaningful activities' and 'parents enable, change and use the environment'. Each theme holds a number of actions (e.g. choosing the right type of meaningful activities for facilitating social contacts) and challenges (e.g. negative attitudes of other people). Less information is available about the needs of parents. CONCLUSIONS: This study indicates that parents apply a broad range of strategies to support participation of their children. They experience many challenges, especially as a result of constraints in the social and physical environments. However, this review also shows that little is known about needs of parents in facilitating participation. As Family-centered service (FCS) philosophy is all about the needs of the child and the family, it is essential to further investigate the needs of the parents and to understand if and to what extent they wish to be supported in enabling their child's participation in daily life