9,660 research outputs found

    A three channel telemetry system

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    A three channel telemetry system intended for biomedical applications is described. The transmitter is implemented in a single chip using a 2 micron BiCMOS processes. The operation of the system and the test results from the latest chip are discussed. One channel is always dedicated to temperature measurement while the other two channels are generic. The generic channels carry information from transducers that are interfaced to the system through on-chip general purpose operational amplifiers. The generic channels have different bandwidths: one from dc to 250 Hz and the other from dc to 1300 Hz. Each generic channel modulates a current controlled oscillator to produce a frequency modulated signal. The two frequency modulated signals are summed and used to amplitude modulate the temperature signal which acts as a carrier. A near-field inductive link telemeters the combined signals over a short distance. The chip operates on a supply voltage anywhere from 2.5 to 3.6 Volts and draws less than 1 mA when transmitting a signal. The chip can be incorporated into ingestible, implantable and other configurations. The device can free the patient from tethered data collection systems and reduces the possibility of infection from subcutaneous leads. Data telemetry can increase patient comfort leading to a greater acceptance of monitoring

    The relationship between parental education and children's schooling in a time of economic turmoil: The case of East Zimbabwe, 2001 to 2011.

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    Using data collected from 1998 to 2011 in a general population cohort study in eastern Zimbabwe, we describe education trends and the relationship between parental education and children's schooling during the Zimbabwean economic collapse of the 2000s. During this period, the previously-rising trend in education stalled, with girls suffering disproportionately; however, female enrolment increased as the economy began to recover. Throughout the period, children with more educated parents continued to have better outcomes such that, at the population level, an underlying increase in the proportion of children with more educated parents may have helped to maintain the upwards education trend

    Protein Losses and Urea Nitrogen Underestimate Total Nitrogen Losses in Peritoneal Dialysis and Hemodialysis Patients

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    Objective: Muscle wasting is associated with increased mortality and is commonly reported in dialysis patients. Hemodialysis (HD) and peritoneal dialysis (PD) treatments lead to protein losses in effluent dialysate. We wished to determine whether changes in current dialysis practice had increased therapy-associated nitrogen losses. / Design: Cross-sectional cohort study. / Methods: Measurement of total protein, urea and total nitrogen in effluent dialysate from 24-hour collections from PD patients, and during haemodiafiltration (HDF) and haemodialysis (HD) sessions. / Subjects: One hundred eight adult dialysis patients. / Intervention: Peritoneal dialysis, high-flux haemodialysis and haemodiafiltration. / Main Outcome Measure: Total nitrogen and protein losses. / Results: Dialysate protein losses were measured in 68 PD and 40 HD patients. Sessional losses of urea (13.9 [9.2-21.1] vs. 4.8 [2.8-7.8] g); protein (8.6 [7.2-11.1] vs. 6.7 [3.9-11.1] g); and nitrogen (11.5 [8.7-17.7] vs. 4.9 [2.6-9.5] g) were all greater for HD than PD, P < .001. Protein-derived nitrogen was 71.9 (54.4-110.4) g for HD and 30.8 (16.1-59.6) g for PD. Weekly protein losses were lower with HD 25.9 (21.5-33.4) versus 46.6 (27-77.6) g/week, but nitrogen losses were similar. We found no difference between high-flux HD and HDF: urea (13.5 [8.8-20.6] vs. 15.3 [10.5-25.5] g); protein (8.8 [7.3-12.2] vs. 7.6 [5.8-9.0] g); and total nitrogen (11.6 [8.3-17.3] vs. 10.8 [8.9-22.5] g). Urea nitrogen (UN) only accounted for 45.1 (38.3-51.0)% PD and 63.0 (55.3-62.4)% HD of total nitrogen losses. / Conclusion: Although sessional losses of protein and UN were greater with HD, weekly losses were similar between modalities. We found no differences between HD and HDF. However, total nitrogen losses were much greater than the combination of protein and UN, suggesting greater nutritional losses with dialysis than previously reported

    Random Spots on Chromospherically Active Stars

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    We have investigated the effect of large numbers of moderately sized spots placed randomly on a differentially rotating star as the explanation of the rotational light curves of magnetically active cool stars. This hypothesis produces light variation very similar to observed light curves of RS CVn binaries, provided there are of order 10-40 spots at any time and provided individual spots have a finite lifetime

    The Rotation Period of the Planet-Hosting Star HD 189733

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    We present synoptic optical photometry of HD 189733, the chromospherically active parent star of one of the most intensively studied exoplanets. We have significantly extended the timespan of our previously reported observations and refined the estimate of the stellar rotation period by more than an order of magnitude: P=11.953±0.009P = 11.953\pm 0.009 days. We derive a lower limit on the inclination of the stellar rotation axis of 56\arcdeg (with 95% confidence), corroborating earlier evidence that the stellar spin axis and planetary orbital axis are well aligned.Comment: To appear in A

    Sovereign debt restructuring : the judge, the vultures and creditor rights

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    What role did the US courts play in the Argentine debt swap of 2005? What implications does this have for the future of creditor rights in sovereign bond markets? The judge in the Argentine case has, it appears, deftly exploited creditor heterogeneity – between holdouts seeking capital gains and institutional investors wanting a settlement – to promote a swap with a supermajority of creditors. Our analysis of Argentine debt litigation reveals a ‘judge-mediated’ sovereign debt restructuring, which resolves the key issues of Transition and Aggregation - two of the tasks envisaged for the IMF’s still-born Sovereign Debt Restructuring Mechanism. For the future, we discuss how judge-mediated sovereign debt restructuring (together with creditor committees) could complement the alternative promoted by the US Treasury, namely collective action clauses in sovereign bond contracts

    The Financialization of US Higher Education

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    Research on financialization has been constrained by limited suitable measures for cases outside of the for-profit sector. Using the case of US higher education, we consider financialization as both increasing reliance on financial investment returns and increasing costs from transactions to acquire capital. We document returns and costs across four types of transactions: (i) revenues from endowment investments, (ii) interest payments on institutional borrowing by colleges, (iii) profits extracted by investors in for-profit colleges and (iv) interest payments on student loan borrowing by households. Estimated annual funding from endowment investments grew from 16billionin2003to16 billion in 2003 to 20 billion in 2012. Meanwhile financing costs grew from 21billionin2003to21 billion in 2003 to 48 billion in 2012, or from 5 to 9% of the total higher education spending, even as interest rates declined. Increases in financial returns, however, were concentrated at wealthy colleges whereas increases in financing costs tended to outpace returns at poorer institutions. We discuss the implications of the findings for resource allocation, organizational governance and stratification among colleges and households.1. Introduction 2. Financialization and higher education 3. Data and measures 4. College endowments and financial revenues 5. College institutional debt and interest costs 6. Proprietary colleges and profits as the costs of equity investment 7. Student loan debt and interest payments 8. Quantifying the costs of higher education financialization 9. Conclusions Supplementary material Funding Acknowledgements References Supplementary dat

    Reliable estimation of prediction uncertainty for physico-chemical property models

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    The predictions of parameteric property models and their uncertainties are sensitive to systematic errors such as inconsistent reference data, parametric model assumptions, or inadequate computational methods. Here, we discuss the calibration of property models in the light of bootstrapping, a sampling method akin to Bayesian inference that can be employed for identifying systematic errors and for reliable estimation of the prediction uncertainty. We apply bootstrapping to assess a linear property model linking the 57Fe Moessbauer isomer shift to the contact electron density at the iron nucleus for a diverse set of 44 molecular iron compounds. The contact electron density is calculated with twelve density functionals across Jacob's ladder (PWLDA, BP86, BLYP, PW91, PBE, M06-L, TPSS, B3LYP, B3PW91, PBE0, M06, TPSSh). We provide systematic-error diagnostics and reliable, locally resolved uncertainties for isomer-shift predictions. Pure and hybrid density functionals yield average prediction uncertainties of 0.06-0.08 mm/s and 0.04-0.05 mm/s, respectively, the latter being close to the average experimental uncertainty of 0.02 mm/s. Furthermore, we show that both model parameters and prediction uncertainty depend significantly on the composition and number of reference data points. Accordingly, we suggest that rankings of density functionals based on performance measures (e.g., the coefficient of correlation, r2, or the root-mean-square error, RMSE) should not be inferred from a single data set. This study presents the first statistically rigorous calibration analysis for theoretical Moessbauer spectroscopy, which is of general applicability for physico-chemical property models and not restricted to isomer-shift predictions. We provide the statistically meaningful reference data set MIS39 and a new calibration of the isomer shift based on the PBE0 functional.Comment: 49 pages, 9 figures, 7 table

    Cost-utility of transcatheter aortic valve implantation for inoperable patients with severe aortic stenosis treated by medical management: a UK cost-utility analysis based on patient-level data from the ADVANCE study.

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    OBJECTIVE: To use patient-level data from the ADVANCE study to evaluate the cost-effectiveness of transcatheter aortic valve implantation (TAVI) compared to medical management (MM) in patients with severe aortic stenosis from the perspective of the UK NHS. METHODS: A published decision-analytic model was adapted to include information on TAVI from the ADVANCE study. Patient-level data informed the choice as well as the form of mathematical functions that were used to model all-cause mortality, health-related quality of life and hospitalisations. TAVI-related resource use protocols were based on the ADVANCE study. MM was modelled on publicly available information from the PARTNER-B study. The outcome measures were incremental cost-effectiveness ratios (ICERs) estimated at a range of time horizons with benefits expressed as quality-adjusted life-years (QALY). Extensive sensitivity/subgroup analyses were undertaken to explore the impact of uncertainty in key clinical areas. RESULTS: Using a 5-year time horizon, the ICER for the comparison of all ADVANCE to all PARTNER-B patients was £13 943 per QALY gained. For the subset of ADVANCE patients classified as high risk (Logistic EuroSCORE >20%) the ICER was £17 718 per QALY gained). The ICER was below £30 000 per QALY gained in all sensitivity analyses relating to choice of MM data source and alternative modelling approaches for key parameters. When the time horizon was extended to 10 years, all ICERs generated in all analyses were below £20 000 per QALY gained. CONCLUSION: TAVI is highly likely to be a cost-effective treatment for patients with severe aortic stenosis

    The COVID-19 pandemic experiences of parents caring for children with oesophageal atresia/tracheo-oesophageal fistula

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    Purpose: The COVID-19 pandemic has resulted in a global health crisis of unparalleled magnitude. The direct risk to the health of children is low. However, disease-containment measures have society-wide impacts. This study explored the pandemic experiences of parents of children with oesophageal atresia/tracheo-oesophageal fistula (OA/TOF) in the UK. Design: A phenomenological approach underpinned use of an asynchronous online forum method, in collaboration with a patient support group. Data were evaluated using thematic analysis. Results: The online forum ran between 7 November and 18 December 2020 with 109 participants. Pandemic experiences were divided into themes relating to healthcare and disease containment. Participants described positive experiences with remote healthcare but identified limitations. Delays and cancellations led to escalation of care to an emergency level, slower developmental progress and feelings of being abandoned by services. Inpatient care was perceived as safe but caring alone was emotionally and practically challenging. Disease containment themes revealed anxiety regarding health risks, ‘collateral’ damage to well-being because of isolation, and an impact on finances and employment. Parents described a transition from worry about direct health risks to concern about the impact of isolation on socialisation and development. A process of risk–benefit analysis led some to transition to a more ‘normal life’, while others continued to isolate. Benefits to their child’s health from isolation were reported. Conclusions: Parents’ experiences of caring for a child with OA/TOF during the pandemic were varied. Rapid adoption of telehealth has demonstrated the enormous potential of remote healthcare delivery but requires refinement to meet the needs of the individual. Future pandemic planning should aim to retain community healthcare services to avoid escalation of care to an emergency, manage chronic and developmental concerns, and support parental well-being. Accurate and consistent disease-specific information is highly valued by parents. Third sector organisations are ideally positioned to support this. Data availability statement: No data are available. Although data have been anonymised, we have not made data available to protect the identity of those involved in the research, due to the detail provided by participants
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