'Everything's fine, so why does it happen?' A qualitative investigation of patients' perceptions of noncardiac chest pain

Aims and objectives. To examine patients’ perceptions and experiences of noncardiac chest pain, within the framework of the common sense model. Background. Patients with noncardiac chest pain have good physical prognosis, but frequently suffer prolonged pain and psychological distress. The common sense model may provide a good framework for examining outcomes in patients with noncardiac chest pain. Design. Qualitative thematic analysis with semi-structured interviews. Methods. In 2010, participants recruited from an emergency department (N = 7) with persistent noncardiac chest pain and distress were interviewed using a semistructured schedule, and data were analysed using thematic analysis. Results. Seven themes were identified; six of which mapped onto core dimensions of the common sense model (identity, cause, timeline, consequences, personal control, treatment control). Contrary to previous research on medically unexplained symptoms, most participants perceived psychological factors to play a causal role in their chest pain. Participants’ perceptions largely mapped onto the common sense model, although there was a lack of coherence across dimensions, particularly with regard to cause. Conclusion. Patients with noncardiac chest pain lack understanding with regard to their condition and may be accepting of psychological causes of their pain. Relevance to clinical practice. Brief psychological interventions aimed at improving understanding of the causes of noncardiac chest pain and providing techniques for managing pain and stress may be useful for patients with noncardiac chest pain

Control of DC power distribution system of a hybrid electric aircraft with inherent overcurrent protection

In this paper, a novel nonlinear control scheme for the on-board DC micro-grid of a hybrid electric aircraft is proposed to achieve voltage regulation of the low voltage (LV) bus and power sharing among multiple sources. Considering the accurate nonlinear dynamic model of each DC/DC converter in the DC power distribution system, it is mathematically proven that accurate power sharing can be achieved with an inherent overcurrent limitation for each converter separately via the proposed control design using Lyapunov stability theory. The proposed framework is based on the idea of introducing a constant virtual resistance at the input of each converter and a virtual controllable voltage that can be either positive or negative, leading to a bidirectional power flow. Compared to existing control strategies for on-board DC micro-grid systems, the proposed controller guarantees accurate power sharing, tight voltage regulation and an upper limit of each source's current at all times, including during transient phenomena. Simulation results of the LV dynamics of an aircraft on-board DC micro-grid are presented to verify the proposed controller performance in terms of voltage regulation, power sharing and the overcurrent protection capability

Control of DC power distribution system of a hybrid electric aircraft with inherent overcurrent protection

In this paper, a novel nonlinear control scheme for the on-board DC micro-grid of a hybrid electric aircraft is proposed to achieve voltage regulation of the low voltage (LV) bus and power sharing among multiple sources. Considering the accurate nonlinear dynamic model of each DC/DC converter in the DC power distribution system, it is mathematically proven that accurate power sharing can be achieved with an inherent overcurrent limitation for each converter separately via the proposed control design using Lyapunov stability theory. The proposed framework is based on the idea of introducing a constant virtual resistance at the input of each converter and a virtual controllable voltage that can be either positive or negative, leading to a bidirectional power flow. Compared to existing control strategies for on-board DC micro-grid systems, the proposed controller guarantees accurate power sharing, tight voltage regulation and an upper limit of each source's current at all times, including during transient phenomena. Simulation results of the LV dynamics of an aircraft on-board DC micro-grid are presented to verify the proposed controller performance in terms of voltage regulation, power sharing and the overcurrent protection capability

Tool development and application: pressure, temperature, spectral gamma ray logging of the SB-15 well

Sandia`s involvement with downhole instrumentation dates from the mid 1970s when work was centered on the development of a high-temperature acoustic borehole televiewer, and the establishment of a list of high- temperature component parts such as resistors, integrated circuits, and sensors. This work evolved into the development of memory logging devices for the US Continental Scientific Drilling Program. These tools were of low cost and very easy to use. Their deployment resulted in scientific advancement in understanding geothermal formations, and a thrust of the current program is to move memory tools from the scientific realm to the commercial environment. The tools developed and utilized in the SB-15 well among other field tests are completely self- contained in that power is obtained from batteries and data are stored in an electronic memory system. Three memory tools form the backbone of the initial Sandia tool suite. Pressure/temperature measurements are necessary for the evaluation of geothermal reservoirs, and they are relatively simple to make. Thus, the initial Sandia program concentrated on such a tool, and it has been successfully used in SB-15. This tool will form the basis for future tools since many engineering principles were proven in its evolution. This pressure/temperature tool combination is very useful in characterizing the geothermal reservoir. Another tool in the Sandia suite measures the natural gamma rays from the formation. This spectral gamma ray tool is useful in defining lithology, paleoflows, and certain clays. SB-15 well logging history and a preliminary interpretation of the data is presented in this report

Comparison of methods for determining leaf area in tree rows

Accepted versio

Modeling the strangeness content of hadronic matter

The strangeness content of hadronic matter is studied in a string-flip model that reproduces various aspects of the QCD-inspired phenomenology, such as quark clustering at low density and color deconfinement at high density, while avoiding long range van der Waals forces. Hadronic matter is modeled in terms of its quark constituents by taking into account its internal flavor (u,d,s) and color (red, blue, green) degrees of freedom. Variational Monte-Carlo simulations in three spatial dimensions are performed for the ground-state energy of the system. The onset of the transition to strange matter is found to be influenced by weak, yet not negligible, clustering correlations. The phase diagram of the system displays an interesting structure containing both continuous and discontinuous phase transitions. Strange matter is found to be absolutely stable in the model.Comment: 14 pages, 1 table, 8 eps figures, revtex. Submitted to Phys. Rev. C, Presented at INPC2001 Berkeley, Ca. july 29-Aug

Is parental mindfulness associated with quality of life and itch intensity in children with psoriasis and eczema and well-being in parents?

Objectives Childhood psoriasis and eczema negatively impact the well-being of children and their parents. Identifying variables that protect against, or reduce, the negative impact of these skin conditions could greatly improve the lives of children with these skin conditions and their parents. We therefore aimed to investigate whether higher levels of parental dispositional mindfulness are associated with lower levels of psychological distress and better quality of life in children with psoriasis or eczema and their parents. Methods Children with psoriasis or eczema (n = 180, M age = 10.22, females = 108) and their parents (n = 210, M age = 39.97, females = 183) were recruited from social media and NHS dermatology clinics in the UK. Parents completed questionnaires assessing dispositional mindfulness, parental stress, psychological distress (depression, anxiety, general stress), and quality of life related to their child’s skin condition. Children completed questionnaires assessing quality of life related to their skin condition and pruritus (itch intensity). Results Parental dispositional mindfulness explained significant amounts of variance in parental stress, parent depression, parent anxiety, parent general stress, and both parent and child quality of life. These relationships were not moderated by skin condition. Conclusion Parental dispositional mindfulness is associated with better well-being in parents of children with psoriasis or eczema, and their children. Mindfulness-based interventions for parents may be beneficial for improving well-being in both children with skin conditions and their parents

Hilbert Lattice Equations

There are five known classes of lattice equations that hold in every infinite dimensional Hilbert space underlying quantum systems: generalised orthoarguesian, Mayet's E_A, Godowski, Mayet-Godowski, and Mayet's E equations. We obtain a result which opens a possibility that the first two classes coincide. We devise new algorithms to generate Mayet-Godowski equations that allow us to prove that the fourth class properly includes the third. An open problem related to the last class is answered. Finally, we show some new results on the Godowski lattices characterising the third class of equations.Comment: 24 pages, 3 figure