Is age a factor in the success or failure of remote monitoring in heart failure? Telemonitoring and structured telephone support in elderly heart failure patients

Background There are few data regarding the effectiveness of remote monitoring for older people with heart failure. We conducted a post-hoc sub-analysis of a previously published large Cochrane systematic review and meta-analysis of relevant randomized controlled trials to determine whether structured telephone support and telemonitoring were effective in this population. Methods A post hoc sub-analysis of a systematic review and meta-analysis that applied the Cochrane methodology was conducted. Meta-analyses of all-cause mortality, all-cause hospitalizations and heart failure-related hospitalizations were performed for studies where the mean or median age of participants was 70 or more years. Results The mean or median age of participants was 70 or more years in eight of the 16 (n=2,659/5,613; 47%) structured telephone support studies and four of the 11 (n=894/2,710; 33%) telemonitoring studies. Structured telephone support (RR 0.80; 95% CI=0.63-1.00) and telemonitoring (RR 0.56; 95% CI=0.41-0.76) interventions reduced mortality. Structured telephone support interventions reduced heart failure-related hospitalizations (RR 0.81; 95% CI=0.67-0.99). Conclusion Despite a systematic bias towards recruitment of individuals younger than the epidemiological average into the randomized controlled trials, older people with heart failure did benefit from structured telephone support and telemonitoring. These post-hoc sub-analysis results were similar to overall effects observed in the main meta-analysis. While further research is required to confirm these observational findings, the evidence at hand indicates that discrimination by age alone may be not be appropriate when inviting participation in a remote monitoring service for heart failure.

GNSS ambiguity resolution with controllable failure rate for long baseline network RTK

Many large-scale GNSS CORS networks have been deployed around the world to support various commercial and scientific applications. To make use of these networks for real-time kinematic positioning services, one of the major challenges is the ambiguity resolution (AR) over long inter-station baselines in the presence of considerable atmosphere biases. Usually, the widelane ambiguities are fixed first, followed by the procedure of determination of the narrowlane ambiguity integers based on the ionosphere-free model in which the widelane integers are introduced as known quantities. This paper seeks to improve the AR performance over long baseline through efficient procedures for improved float solutions and ambiguity fixing. The contribution is threefold: (1) instead of using the ionosphere-free measurements, the absolute and/or relative ionospheric constraints are introduced in the ionosphere-constrained model to enhance the model strength, thus resulting in the better float solutions; (2) the realistic widelane ambiguity precision is estimated by capturing the multipath effects due to the observation complexity, leading to improvement of reliability of widelane AR; (3) for the narrowlane AR, the partial AR for a subset of ambiguities selected according to the successively increased elevation is applied. For fixing the scalar ambiguity, an error probability controllable rounding method is proposed. The established ionosphere-constrained model can be efficiently solved based on the sequential Kalman filter. It can be either reduced to some special models simply by adjusting the variances of ionospheric constraints, or extended with more parameters and constraints. The presented methodology is tested over seven baselines of around 100 km from USA CORS network. The results show that the new widelane AR scheme can obtain the 99.4 % successful fixing rate with 0.6 % failure rate; while the new rounding method of narrowlane AR can obtain the fix rate of 89 % with failure rate of 0.8 %. In summary, the AR reliability can be efficiently improved with rigorous controllable probability of incorrectly fixed ambiguities.

Predicting the likelihood of QA failure using treatment plan accuracy metrics

This study used automated data processing techniques to calculate a set of novel treatment plan accuracy metrics, and investigate their usefulness as predictors of quality assurance (QA) success and failure. 151 beams from 23 prostate and cranial IMRT treatment plans were used in this study. These plans had been evaluated before treatment using measurements with a diode array system. The TADA software suite was adapted to allow automatic batch calculation of several proposed plan accuracy metrics, including mean field area, small-aperture, off-axis and closed-leaf factors. All of these results were compared the gamma pass rates from the QA measurements and correlations were investigated. The mean field area factor provided a threshold field size (5 cm2, equivalent to a 2.2 x 2.2 cm2 square field), below which all beams failed the QA tests. The small aperture score provided a useful predictor of plan failure, when averaged over all beams, despite being weakly correlated with gamma pass rates for individual beams. By contrast, the closed leaf and off-axis factors provided information about the geometric arrangement of the beam segments but were not useful for distinguishing between plans that passed and failed QA. This study has provided some simple tests for plan accuracy, which may help minimise time spent on QA assessments of treatments that are unlikely to pass.

Sub-modelling for the ratchetting failure of insulated rail joints

Insulated rail joints are critical for train safety as they control electrical signalling systems; unfortunately they exhibit excessive ratchetting of the railhead near the endpost insulators. This paper reports a three-dimensional global model of these joints under wheel–rail contact pressure loading and a sub-model examining the ratchetting failures of the railhead. The sub-model employs a non-linear isotropic–kinematic elastic–plastic material model and predicts stress/strain levels in the localised railhead zone adjacent to the endpost which is placed in the air gap between the two rail ends at the insulated rail joint. The equivalent plastic strain plot is utilised to capture the progressive railhead damage adequately. Associated field and laboratory testing results of damage to the railhead material suggest that the simulation results are reasonable.

Factor Five : Transforming the Global Economy through 80% Improvements in Resource Productivity

The 21st century will see monumental change. Either the human race will use its knowledge and skills and change the way it interacts with the environment, or the environment will change the way it interacts with its inhabitants. In the first case, the focus of this book, we would see our sophisticated understanding in areas such as physics, chemistry, engineering, biology, planning, commerce, business and governance accumulated over the last 1,000 years brought to bear on the challenge of dramatically reducing our pressure on the environment. The second case however is the opposite scenario, involving the decline of the planet’s ecosystems until they reach thresholds where recovery is not possible, and following which we have no idea what happens. For instance, if we fail to respond to Sir Nicolas Stern’s call to meet appropriate stabilisation trajectories for greenhouse gas emissions, and we allow the average temperature of our planets surface to increase by 4-6 degrees Celsius, we will see staggering changes to our environment, including rapidly rising sea level, withering crops, diminishing water reserves, drought, cyclones, floods… allowing this to happen will be the failure of our species, and those that survive will have a deadly legacy. In this update to the 1997 International Best Seller, Factor Four, Ernst von Weizsäcker again leads a team to present a compelling case for sector wide advances that can deliver significant resource productivity improvements over the coming century. The purpose of this book is to inspire hope and to then inform meaningful action in the coming decades to respond to the greatest challenge our species has ever faced – that of living in harmony with our planet and its other inhabitants.

Liability in negligence and the failure to disclose multiple risks in surgery : I would have been willing to run the risk

It has been 21 years since the decision in Rogers v Whitaker and the legal principles concerning informed consent and liability for negligence are still strongly grounded in this landmark High Court decision. This paper considers more recent developments in the law concerning the failure to disclose inherent risks in medical procedures, focusing on the decision in Wallace v Kam [2013] HCA 19. In this case, the appellant underwent a surgical procedure that carried a number of risks. The surgery itself was not performed in a sub-standard way, but the surgeon failed to disclose two risks to the patient, a failure that constituted a breach of the surgeon’s duty of care in negligence. One of the undisclosed risks was considered to be less serious than the other, and this lesser risk eventuated causing injury to the appellant. The more serious risk did not eventuate, but the appellant argued that if the more serious risk had been disclosed, he would have avoided his injuries completely because he would have refused to undergo the procedure. Liability was disputed by the surgeon, with particular reference to causation principles. The High Court of Australia held that the appellant should not be compensated for harm that resulted from a risk he would have been willing to run. We examine the policy reasons underpinning the law of negligence in this specific context and consider some of the issues raised by this unusual case. We question whether some of the judicial reasoning adopted in this case, represents a significant shift in traditional causation principles.

Unidentified vehicle in multi-vehicle accident - failure to notify Nominal Defendant no bar to proceedings against it

In Kumar v Suncorp Metway Insurance Limited [2004] QSC 381 Douglas J examined s37 of the Motor Accident Insurance Act 1994 (Qld) in the context of an accident involving multiple insurers when a notice of accident had not been given to the Nominal Defendant

Failure of discontinuous railhead edges due to plastic strain accumulation

Railhead is perhaps the highest stressed civil infrastructure due to the passage of heavily loaded wheels through a very small contact patch. The stresses at the contact patch cause yielding of the railhead material and wear. Many theories exist for the prediction of these mechanisms of continuous rails; this process in the discontinuous rails is relatively sparingly researched. Discontinuous railhead edges fail due to accumulating excessive plastic strains. Significant safety concern is widely reported as these edges form part of Insulated Rail Joints (IRJs) in the signalling track circuitry. Since Hertzian contact is not valid at a discontinuous edge, 3D finite element (3DFE) models of wheel contact at a railhead edge have been used in this research. Elastic–plastic material properties of the head hardened rail steel have been experimentally determined through uniaxial monotonic tension tests and incorporated into a FE model of a cylindrical specimen subject to cyclic tension load- ing. The parameters required for the Chaboche kinematic hardening model have been determined from the stabilised hysteresis loops of the cyclic load simulation and imple- mented into the 3DFE model. The 3DFE predictions of the plastic strain accumulation in the vicinity of the wheel contact at discontinuous railhead edges are shown to be affected by the contact due to passage of wheels rather than the magnitude of the loads the wheels carry. Therefore to eliminate this failure mechanism, modification to the contact patch is essential; reduction in wheel load cannot solve this problem.

Performance evaluation of three-level Z-source inverters under semiconductor-failure conditions

This paper evaluates and proposes various compensation methods for three-level Z-source inverters under semiconductor-failure conditions. Unlike the fault-tolerant techniques used in traditional three-level inverters, where either an extra phase-leg or collective switching states are used, the proposed methods for three-level Z-source inverters simply reconfigure their relevant gating signals so as to ride-through the failed semiconductor conditions smoothly without any significant decrease in their ac-output quality and amplitude. These features are partly attributed to the inherent boost characteristics of a Z-source inverter, in addition to its usual voltage-buck operation. By focusing on specific types of three-level Z-source inverters, it can also be shown that, for the dual Z-source inverters, a unique feature accompanying it is its extra ability to force common-mode voltage to zero even under semiconductor-failure conditions. For verifying these described performance features, PLECS simulation and experimental testing were performed with some results captured and shown in a later section for visual confirmation.

A typology of technological enablers of website service failure prevention

An increasing range of services are now offered via online applications and e-commerce websites. However, problems with online services still occur at times, even for the best service providers due to the technical failures, informational failures, or lack of required website functionalities. Also, the widespread and increasing implementation of web services means that service failures are both more likely to occur, and more likely to have serious consequences. In this paper we first develop a digital service value chain framework based on existing service delivery models adapted for digital services. We then review current literature on service failure prevention, and provide a typology of technolo- gies and approaches that can be used to prevent failures of different types (functional, informational, system), that can occur at different stages in the web service delivery. This makes a contribution to theory by relating specific technologies and technological approaches to the point in the value chain framework where they will have the maximum impact. Our typology can also be used to guide the planning, justification and design of robust, reliable web services.

Failure of amino acid homeostasis causes cell death following proteasome inhibition

The ubiquitin-proteasome system targets many cellular proteins for degradation and thereby controls most cellular processes. Although it is well established that proteasome inhibition is lethal, the underlying mechanism is unknown. Here, we show that proteasome inhibition results in a lethal amino acid shortage. In yeast, mammalian cells, and flies, the deleterious consequences of proteasome inhibition are rescued by amino acid supplementation. In all three systems, this rescuing effect occurs without noticeable changes in the levels of proteasome substrates. In mammalian cells, the amino acid scarcity resulting from proteasome inhibition is the signal that causes induction of both the integrated stress response and autophagy, in an unsuccessful attempt to replenish the pool of intracellular amino acids. These results reveal that cells can tolerate protein waste, but not the amino acid scarcity resulting from proteasome inhibition.

Artemisinin-induced parasite dormancy : a plausible mechanism for treatment failure

Background Artemisinin-combination therapy is a highly effective treatment for uncomplicated falciparum malaria but parasite recrudescence has been commonly reported following artemisinin (ART) monotherapy. The dormancy recovery hypothesis has been proposed to explain this phenomenon, which is different from the slower parasite clearance times reported as the first evidence of the development of ART resistance. Methods In this study, an existing P. falciparum infection model is modified to incorporate the hypothesis of dormancy. Published in vitro data describing the characteristics of dormant parasites is used to explore whether dormancy alone could be responsible for the high recrudescence rates observed in field studies using monotherapy. Several treatment regimens and dormancy rates were simulated to investigate the rate of clinical and parasitological failure following treatment. Results The model output indicates that following a single treatment with ART parasitological and clinical failures occur in up to 77% and 67% of simulations, respectively. These rates rapidly decline with repeated treatment and are sensitive to the assumed dormancy rate. The simulated parasitological and clinical treatment failure rates after 3 and 7 days of treatment are comparable to those reported from several field trials. Conclusions Although further studies are required to confirm dormancy in vivo, this theoretical study adds support for the hypothesis, highlighting the potential role of this parasite sub-population in treatment failure following monotherapy and reinforcing the importance of using ART in combination with other anti-malarials.

Artemisinin induced dormancy in Plasmodium falciparum : duration, recovery rates and implications in treatment failure

Background Despite the remarkable activity of artemisinin and its derivatives, monotherapy with these agents has been associated with high rates of recrudescence. The temporary arrest of the growth of ring-stage parasites (dormancy) after exposure to artemisinin drugs provides a plausible explanation for this phenomenon. Methods Ring-stage parasites of several Plasmodium falciparum lines were exposed to different doses of dihydroartemisinin (DHA) alone or in combination with mefloquine. For each regime, the proportion of recovering parasites was determined daily for 20 days. Results Parasite development was abruptly arrested after a single exposure to DHA, with some parasites being dormant for up to 20 days. Approximately 50% of dormant parasites recovered to resume growth within the first 9 days. The overall proportion of parasites recovering was dose dependent, with recovery rates ranging from 0.044% to 1.313%. Repeated treatment with DHA or with DHA in combination with mefloquine led to a delay in recovery and an ∼10-fold reduction in total recovery. Strains with different genetic backgrounds appeared to vary in their capacity to recover. Conclusions These results imply that artemisinin-induced arrest of growth occurs readily in laboratory-treated parasites and may be a key factor in P. falciparum malaria treatment failure.

Integrating the impact of climate into event based failure models for water pipes

This paper presents an event-based failure model to predict the number of failures that occur in water distribution assets. Often, such models have been based on analysis of historical failure data combined with pipe characteristics and environmental conditions. In this paper weather data have been added to the model to take into account the commonly observed seasonal variation of the failure rate. The theoretical basis of existing logistic regression models is briefly described in this paper, along with the refinements made to the model for inclusion of seasonal variation of weather. The performance of these refinements is tested using data from two Australian water authorities.

Seasonal factors influencing the failure of buried water reticulation pipes

While the use of environmental factors in the analysis and prediction of failures of buried reticulation pipes in cold environments has been the focus of extensive work, the same cannot be said for failures occurring on pipes in other (non-freezing) environments. A novel analysis of pipe failures in such an environment is the subject of this paper. An exploratory statistical analysis was undertaken, identifying a peak in failure rates during mid to late summer. This peak was found to correspond to a peak in the rate of circumferential failures, whilst the rate of longitudinal failures remained constant. Investigation into the effect of climate on failure rates revealed that the peak in failure rates occurs due to differential soil movement as the result of shrinkage in expansive soils.