Lewis hybrid computing system, users manual

The Lewis Research Center's Hybrid Simulation Lab contains a collection of analog, digital, and hybrid (combined analog and digital) computing equipment suitable for the dynamic simulation and analysis of complex systems. This report is intended as a guide to users of these computing systems. The report describes the available equipment' and outlines procedures for its use. Particular is given to the operation of the PACER 100 digital processor. System software to accomplish the usual digital tasks such as compiling, editing, etc. and Lewis-developed special purpose software are described

A lumped parameter mathematical model for simulation of subsonic wind tunnels

Equations for a lumped parameter mathematical model of a subsonic wind tunnel circuit are presented. The equation state variables are internal energy, density, and mass flow rate. The circuit model is structured to allow for integration and analysis of tunnel subsystem models which provide functions such as control of altitude pressure and temperature. Thus the model provides a useful tool for investigating the transient behavior of the tunnel and control requirements. The model was applied to the proposed NASA Lewis Altitude Wind Tunnel (AWT) circuit and included transfer function representations of the tunnel supply/exhaust air and refrigeration subsystems. Both steady state and frequency response data are presented for the circuit model indicating the type of results and accuracy that can be expected from the model. Transient data for closed loop control of the tunnel and its subsystems are also presented, demonstrating the model's use as a control analysis tool

The impact of a DBT training on the counselor self-efficacy of preservice counselors working with borderline personality disordered clients

As the demand for community mental health services grows, more and more counselors-in-training are being asked to face the challenge of working with high needs clients, including clients with Borderline Personality Disorder (BPD). Counselors-in-training are entering therapeutic relationships with high-risk clients without training specifically covering BPD client's unique needs. This lack of training has the potential to limit the counselor self-efficacy (CSE) of counselors-in-training. Researchers speculate that counselor self-efficacy (CSE) impacts the outcome of therapy. Larson (1998) believes that CSE is one of the major indicators of effective counseling. However, without specific training in how to work effectively with personality disorders such as BPD, many counselors-in-training are feeling ineffective and incompetent with regards to their work with this growing and needy population. Several empirical studies have emerged on different psychotherapies and practices which may benefit individuals with BPD. The most empirically based therapy for clients with BPD is Dialectical Behavior Therapy (DBT) (Linehan, Armstrong, Suarez, Allmon, & Heard, 1991; Lynch, Chapman, Rosenthal, & Linehan, 2006; McMain & Korman, 2001; Neacsiu, Rizvi, & Linehan, 2010; Soler, et al., 2009). An understanding of the skills and interventions taught in DBT has been shown to be valuable not only to the client, but also therapists working with BPD individuals. One question that has not been addressed in the counseling literature is how training in DBT might impact the counselor self-efficacy of counselors-in-training with regards to their work with BPD clients

Insight Report: COVID-19 Community Involvement - “Let’s Talk About…HIV Care”

This informal session led by the Patient Experience Research Centre (PERC), in collaboration with Positively UK, invited people living with, affected by, or working in HIV to share their experience, views, questions and concerns on accessing HIV care during COVID-19. The aim of the call was to gather feedback on specific areas to help guide a proposed qualitative (interview-based study) looking to explore experiences, specifically on: 1. Challenges and concerns in managing HIV care during COVID-19 2. Challenges in the provision of HIV care during COVID-19 3. Opportunities presented for HIV care during COVID-19 We also wished to inspire new ways to rapidly engage and involve communities remotely during a public health emergency, through strengthening partnerships with existing groups (in this case, Positively UK)

Experience of primary care for people with HIV: a mixed-method analysis

Background Advances in treatment have transformed HIV into a long-term condition (LTC), presenting fresh challenges for health services, HIV specialists and general practitioners (GPs). Aim To explore the experience of people living with HIV (PLHIV) regarding using their GPs. Design and setting A mixed-method analysis using data from two sources: a nationally-representative survey of PLHIV and a qualitative study with London-based PLHIV. Methods Univariate logistic regression for quantitative data and Framework analysis for qualitative data. Results The survey had 4,422 participants; the qualitative study included 52 participants. In both studies, GP registration and HIV status disclosure were high. Similar to general population trends, recent GP use was associated with poor self-rated health status, co-morbidities, older age and lower socioeconomic status. Two-thirds reported a good experience with GPs; a lower proportion felt comfortable asking HIV-related questions. Actual or perceived HIV stigma were consistently associated with poor satisfaction. In the interviews, participants with additional LTCs valued sensitive and consistent support from GPs. Some anticipated, and sometimes experienced, problems relating to HIV status, GPs’ limited experience and time to manage their complex needs. Sometimes they took their own initiatives to facilitate coordination and communication. For PLHIV, a ‘good’ GP offered continuity and took time to know and accept them without judgement. Conclusion We suggest clarification of roles and provision of relevant support to build confidence in GPs and primary care staff to care for PLHIV. As PLHIV population ages, there is a strong need to develop trusting patient/GP relationships and HIV-friendly GP practices

“I’d rather wait and see what’s around the corner”: a multi-perspective qualitative study of treatment escalation planning in frailty

Introduction People living with frailty risk adverse outcomes following even minor illnesses. Admission to hospital or the intensive care unit is associated with potentially burdensome interventions and poor outcomes. Decision-making during an emergency is fraught with complexity and potential for conflict between patients, carers and clinicians. Advance care planning is a process of shared decision-making which aims to ensure patients are treated in line with their wishes. However, planning for future care is challenging and those living with frailty are rarely given the opportunity to discuss their preferences. The aim of the ProsPECT (Prospective Planning for Escalation of Care and Treatment) study was to explore perspectives on planning for treatment escalation in the context of frailty. We spoke to people living with frailty, their carers and clinicians across primary and secondary care. Methods In-depth online or telephone interviews and online focus groups. The topic guide explored frailty, acute decision-making and planning for the future. Data were thematically analysed using the Framework Method. Preliminary findings were presented to a sample of study participants for feedback in two online workshops. Results We spoke to 44 participants (9 patients, 11 carers and 24 clinicians). Four main themes were identified: frailty is absent from treatment escalation discussions, planning for an uncertain future, escalation in an acute crisis is ‘the path of least resistance’, and approaches to facilitating treatment escalation planning in frailty. Conclusion Barriers to treatment escalation planning include a lack of shared understanding of frailty and uncertainty about the future. Emergency decision-making is focussed on survival or risk aversion and patient preferences are rarely considered. To improve planning discussions, we recommend frailty training for non-specialist clinicians, multi-disciplinary support, collaborative working between patients, carers and clinicians as well as broader public engagement

Ichthyological Bulletin of the J.L.B. Smith Institute of Ichthyology; No. 50

The publication of a new phase of research on the fishes of the Okavango drainage starts with this account which gives the valid names and broad distribution patterns of all species known from the system. Eighty species and subspecies are recognised, of which at least two (Parakneria fortuita Penrith; Serranochromis gracilis Greenwood) are endemic. Notes on early collections, synonymy, taxonomic status and distribution are given. New synonyms are recognized under Aplocheilichthys hutereaui (A. schalleri), Aplocheilichthys johnstoni (Haplochilus carlislei) and Ctenopoma multispinis (Ctenopoma machadoi) respectively. Recently published taxonomic changes are incorporated including two genera (Mesobola and Afromastacembelus), a species Serranochromis (Sargochromis) gracilis and the re-allocated Amphilius uranoscopus. The Zambezian Hemichromis species is re-identified as H. elongatus. A number of unresolved taxonomic problems are pointed out and certain dubious records are excluded from the checklist. The Okavango has a diverse fish fauna with tropical affinities. Many fish species are poorly studied. Man-induced threats to the continued natural functioning of this complex and dynamic system, especially large-scale water abstraction, overgrazing, deforestation and biocide spraying to eliminate tsetse fly, make it imperative that studies on the nature and role of the fishes are continued.Rhodes University Libraries (Digitisation

Quantifying the potential exposure hazard due to energetic releases of CO2 from a failed sequestration well

AbstractWells are designed to bring fluids from depth to the earth’s surface quickly. As such they are the most likely pathway for CO2 to return to the surface in large quantities and present a hazard without adequate management. We surveyed oil industry experience of CO2 well failures, and separately, calculated the maximal CO2 flow rate from a 5000 ft depth supercritical CO2 reservoir. The calculated maximum of 20,000 tonne/day was set by the sound speed and the seven-inch well casing diameter, and was greater than any observed event. We used this flux to simulate atmospheric releases and the associated hazard utilizing the National Atmospheric Release Advisory Center (NARAC) tools and real meteorology at a representative location in the High Plains of the United States. Three cases representing a maximum hazard day (quiet winds <1 m s−1 near the wellhead) and medium and minimal hazard days (average winds 3 m s−1 and 7 m s−1) were assessed. As expected for such large releases, there is a near-well hazard when there is little or no wind. In all three cases the hazardous Temporary Emergency Exposure Levels (TEEL) 2 or 3 only occurred within the first few hundreds of meters. Because the preliminary 3-D model runs may not have been run at high enough resolution to accurately simulate very small distances, we also used a simple Gaussian plume model to provide an upper bound on the distance at which hazardous conditions might exist. This extremely conservative model, which ignores inhomogeneity in the mean wind and turbulence fields, also predicts possible hazardous concentrations up to several hundred meters downwind from a maximal release