Limited Time Horizon Research Articles

Multimorbidity through the lens of life-limiting illness: how helpful are Australian clinical practice guidelines to its management in primary care?

This study assessed Australian clinical practice guidelines for life-limiting index conditions for the extent to which they acknowledged comorbidities and framed management recommendations within the context of older age and reduced life expectancy. A comprehensive search identified current, evidence-based Australian guidelines for chronic life-limiting conditions directed at general practitioners. Guideline content was analysed qualitatively before comorbidity acknowledgements were quantified using a 17-item checklist. Full guidelines were quality appraised using AGREE-II. Ten documents covering chronic obstructive pulmonary disease, heart failure, cancer pain, dementia and palliative care in aged care were identified. Most guidelines addressed one 'comorbid' condition and prompted clinicians to consider patient quality of life and personal preferences. Fewer addressed burden of treatment and half suggested modifying treatments to account for limited life expectancy, age or time horizon to benefit. Half warned of potential adverse drug interactions. Guidelines were of moderate to very high quality. Guidelines naturally prioritised their index condition, directing attention to only the most common comorbidities. However, there may be scope to include more condition-agnostic guidance on multimorbidity management. This might be modelled on the 'guiding principles' approach now emerging internationally from organisations such as the American Geriatrics Society in response to increasing multimorbidity prevalence and evidence limitations.

<i>Corrigendum to</i>: Multimorbidity through the lens of life-limiting illness: how helpful are Australian clinical practice guidelines to its management in primary care?

This study assessed Australian clinical practice guidelines for life-limiting index conditions for the extent to which they acknowledged comorbidities and framed management recommendations within the context of older age and reduced life expectancy. A comprehensive search identified current, evidence-based Australian guidelines for chronic life-limiting conditions directed at general practitioners. Guideline content was analysed qualitatively before comorbidity acknowledgements were quantified using a 17-item checklist. Full guidelines were quality appraised using AGREE-II. Ten documents covering chronic obstructive pulmonary disease, heart failure, cancer pain, dementia and palliative care in aged care were identified. Most guidelines addressed one 'comorbid' condition and prompted clinicians to consider patient quality of life and personal preferences. Fewer addressed burden of treatment and half suggested modifying treatments to account for limited life expectancy, age or time horizon to benefit. Half warned of potential adverse drug interactions. Guidelines were of moderate to very high quality. Guidelines naturally prioritised their index condition, directing attention to only the most common comorbidities. However, there may be scope to include more condition-agnostic guidance on multimorbidity management. This might be modelled on the 'guiding principles' approach now emerging internationally from organisations such as the American Geriatrics Society in response to increasing multimorbidity prevalence and evidence limitations.

A gray-box model for real-time transient temperature predictions in data centers

In response to the need to improve the energy efficiency of data centers (DCs), system designers now incorporate solutions such as continuous performance monitoring, automated diagnostics, and optimal control. While these solutions must ideally be able to predict transient conditions, in particular real time DC temperatures, existing forecasting methods are inadequate because they (1) make restrictive assumptions about system configurations, (2) are extremely time-consuming for real time applications, (3) are accurate only over limited time horizons, (4) fail to accurately model the effects of operating conditions, such as cooling unit operation conditions and server workloads, or (5) ignore important facets of the flow physics and heat transfer that can lead to large prediction errors in extrapolative predictions. To address these deficiencies, we develop a gray-box model that combines machine learning with the thermofluid transport equations relevant for a row-based cooled DC to predict transient temperatures in server CPUs and cold air inlet to the servers. An artificial neural network (ANN) embedded in the gray-box model predicts pressures, which provide inputs for the thermofluid transport equations that predict the spatio-temporal temperature distributions. The model is validated with experimental measurements for different (1) server workload distributions, (2) cooling unit set-point temperatures and (3) the airflow of the cooling units. This gray-box model exhibits superior performance compared to a conventional zonal temperature prediction model and an advanced black-box model that is based on a nonlinear autoregressive exogenous model. An application of the gray-box model involves a case study to detect cooling unit fan failure in a row-based DC cooling system.

An Adaptive Control Scheme for Interleukin-2 Therapy.

SummaryRegulatory T cells (Treg) are suppressor cells that control self-reactive and excessive effector conventional T helper cell (Tconv) responses. Breakdown of the balance between Tregs and Tconvs is a hallmark of autoimmune and inflammatory diseases. Interleukin-2 (IL-2) is a growth factor for both populations and subtle leverage to restore the healthy immune balance in IL-2 therapy. By using a mechanistic mathematical model, we introduced an adaptive control strategy to design the minimal therapeutic IL-2 dosage required to increase and stabilize Treg population and restrict inflammatory response. This adaptive protocol allows for dose adjustments based on the feedback of the immune kinetics of the patient. Our simulation results showed that a minimal Treg population was required to restrict the transient side effect of IL-2 injections on the effector Tconv response. In silico results suggested that a combination of IL-2 and adoptive Treg transfer therapies can limit this side effect.

Learning communities and co-creative tourism practices in NGDO projects

In this study, we considered tourism collaboration for sustainable development as a co-creative practice of learning about tourism in order to achieve benefits for local communities. We focused on projects run by non-governmental development organisations (NGDOs) and the challenges relating to their long-term impact. These challenges concern the projects’ potential to facilitate the emergence and/or reinforcement of local learning communities. The study was conducted by an academic and a representative of the NGDO that constituted the empirical case. The empirical investigation was based on a variety of data sources and explored both the NGDO’s strategic approach to collaboration and the experience gained from two projects. We identified factors that can be crucially important for the promotion of collaboration driven by local actors and extending beyond the limited time horizon of the NGDOs’ projects. The paper contributes to the literature by adopting the concepts of co-creative practices and communities of practice (CoPs) to study collaboration, elucidating the evolving linkages connecting CoP constellations in learning communities. The study also presents some reflections on collaborative research with non-academics as a useful way of promoting plurality, depth and reflexivity.

Direct marketing of an event under hazards of customer saturation and forgetting

We address the problem of optimising the intensity of online advertising. In contrast to the classical literature, we tackle the advertising interaction between the firm and the potential customer, for the sale of a onetime event, in a very limited time horizon. The problem is intrinsically dynamic due to two conflicting situations: the first arises when the customer is subjected to intense advertising pressure, which may lead to customer saturation and even irritation, while the second is the tendency for customers to forget if they are not reminded systematically through advertising. In order to determine an optimal event-advertising policy and develop an efficient enumerative shooting algorithm to solve the problem, we suggest a hazard rate-based approach to modelling the conflicting factors. Our analysis shows that the initial level of customer interest in the event has a non-trivial effect on the dynamics of the optimal advertising policy. In particular, this advertising policy consists of a monotonic increase over time prior to the event in the case of high initial interest and a concave, peak-wise form in the case of low initial interest.

A two-stage stochastic model for pig production planning in vertically integrated production systems

This paper focuses on vertically integrated pig companies based on multi-farm systems. The aim is to address tactical decisions to plan production, increase flexibility, improve coordination and overall pig production under the uncertainty associated with future selling price. Decisions to purchase additional piglets and/or rent farms to adapt system capacity were considered. We propose a two-stage stochastic programming model with selling price as a stochastic parameter under a limited time horizon and a case study to illustrate their use. The model maximizes the net revenue of the system by considering a steady piglet production on sow farms and the corresponding animal flow according to growth stage throughout different farms such as breeding, rearing and fattening farms. All-in-all-out management and marketing time window to sell pigs to the abattoir were modeled on fattening farms. The stochastic solution for the case study provides an optimal first stage production plan regarding the purchase of 1016 piglets/week in addition to the 775 already produced beside the renting of rearing and fattening farms taking into account the different scenarios may happen in the future. The model is capable of identifying inefficiencies or bottlenecks in the system. We discuss the value of the stochastic solution of k€1683 compared to the deterministic solution, and concluding the valuable incorporation of uncertainty.

Limited time commitment: Does competition for providing scarce products always improve the supplies?

In addition to the fact that goods and services typically become scarce because resources are scarce, scarcity involves a psychological aspect. When a product is limited in availability, or perceived as being limited, it becomes more attractive. As a result, as long as the product is viewed as scarce, a surplus in supplies implies an increase in consumption. Motivated by fresh-water scarcity, we address the problem of dynamic interaction between two firms committing to provide water supply within a limited time horizon. We find that competition does not necessarily reduce product scarcity compared to the monopolistic industry. In particular, commitment-based market equilibrium is characterized by a critical duration of the supply contract. Duopolistic competition within this duration is reminiscent of the conventional quantity competition—the supply grows and the price drops compared to the monopolistic output. On the other hand, a longer contract leads to a different operational outcome—the monopoly becomes gradually more beneficial in terms of supplies and, as the time horizon grows, even overwhelmingly advantageous, thereby resulting in lower scarcity of the products.

Longevity trend risk over limited time horizons

AbstractWe consider various aspects of longevity trend risk viewed through the prism of a finite time window. We show the broad equivalence of value-at-risk (VaR) capital requirements at a p-value of 99.5% to conditional tail expectations (CTEs) at 99%. We also show how deferred annuities have higher risk, which can require double the solvency capital of equivalently aged immediate anuities. However, results vary considerably with the choice of model and so longevity trend-risk capital can only be determined through consideration of multiple models to inform actuarial judgement. This model risk is even starker when trying to value longevity derivatives. We briefly discuss the importance of using smoothed models and describe two methods to considerably shorten VaR and CTE run times.

Dissimilarity between turbulent heat and momentum transfer induced by a streamwise travelling wave of wall blowing and suction

A series of direct numerical simulations of a fully developed turbulent channel flow is conducted in order to clarify the effects of travelling wave-like wall blowing and suction on dissimilar heat transfer enhancement. While the wave form is kept sinusoidal and its amplitude is set to be 5 % of the bulk mean velocity, the wavelength and phase speed of the travelling wave are systematically changed in a wide parameter space. As a result, the global optimum of the parameter set for maximizing the analogy factor, which is defined as the ratio between the Stanton number and the skin-friction coefficient, is identified. Interestingly, the obtained globally optimal mode agrees well with that predicted from the optimal control theory taking into account the future dynamics within a limited time horizon by Yamamoto et al. (J. Fluid Mech., vol. 733, 2013, pp. 189–220). The instantaneous velocity and thermal fields are decomposed into coherent and random components in order to evaluate the contribution from each component to dissimilar heat transfer enhancement. The detailed mechanisms of dissimilarity are explained by the budget analyses of the coherent and random contributions. Also, their relationships with the near-wall turbulent structures modified by the applied control are discussed through flow visualization. It is found that the random component makes a dominant contribution to dissimilarity, and this can be explained by an indirect effect through the modification of the coherent field by the applied control. Based on the above mechanisms, we propose a simple unsteady Reynolds-averaged Navier–Stokes (URANS) approach, where the phase-averaged velocity and thermal fields are solved directly whereas the effects of the random component are modelled by the Boussinesq eddy viscosity and diffusivity hypothesis. It is shown that the present URANS can capture the overall trend of dissimilar heat transfer enhancement in a wide parameter range. The present results also explain why the optimal control theory with a limited time horizon succeeds in predicting the globally optimal control mode.

SELECTIVE NARROWING OF PERIPHERAL SOCIAL NETWORKS PREDICTS POOR LONG-TERM COGNITION IN OLD AGE

Socioemotional selectivity theory posits that emotionally meaningful goals such as spending precious time with close family and friends are prioritized in late life as a function of limited future time horizons. Research documents that older individuals include a smaller proportion of peripheral social partners than younger individuals in their social networks, and that this selectivity is associated with better daily emotional experience (English & Carstensen, 2014). Such limitation of social partners, however, might adversely affect cognitive function in the long run, since exposure to novel and cognitively stimulating environments has been tied to better cognitive functioning (Park et al., 2014). The current study examined the long-term association between proportions of peripheral social partners in older adults’ social networks and cognitive performance. Sixty-one older participants (Mage = 71.53) reported the size of their inner, middle, and outer social circles using the Social Convoy Questionnaire (Kahn & Antonucci, 1980) and completed Digit Span Backward, Digit Span Forward, and Digit Symbol tasks at baseline and five years later. Results of multiple regression analysis show that participants who had a smaller proportion of social partners in their outer social circle at baseline performed poorer on the Backward Span task assessed five years later than those with a larger outer circle proportion. Results hold controlling baseline cognition, physical health, age, SES, education, and trait openness. We discuss the findings in terms of potential tradeoffs between the age-related social selection and working memory in the long run.

The value of foresight in the drybulk freight market

We analyze the value of foresight in the drybulk freight market when repositioning a vessel through space and time. In order to do that, we apply an optimization model on a network with dynamic regional freight rate differences and stochastic travel times. We evaluate the value of the geographical switching option for three cases: the upper bound based on having perfect foresight, the baseline set by a random strategy, and the case of perfect foresight but only for a limited time horizon. By combining a neural network with optimization, we can assess the impact of varying foresight horizons on economic performance. In a simple but realistic two-region case, we evaluate empirically that the upper bound for large vessels can be as high as 25% cumulative outperformance, and that a significant portion of this theoretical value can be captured with limited foresight of a few weeks. Our research sheds light on the important issue of spatial efficiency in global ocean freight markets and provides a useful upper bound for the value of investing in predictive analysis.

PCN38 ECONOMIC ANALYSIS OF COLORECTAL CANCER SCREENING FROM MULTIPLE STAKEHOLDER PERSPECTIVES: KEY COMPONENTS TO IMPROVE PRACTICAL APPLICATIONS IN THE US

Colorectal cancer (CRC) screening reduces morbidity and mortality due to CRC. Intended to inform healthcare policy decisions, the majority of CRC screening economic evaluations are cost-effectiveness analyses with a societal perspective over a lifetime horizon. Although informative, these analyses do not assess the total cost of CRC screening from the perspectives of delivery systems, payers, or employers. In the heterogeneous US healthcare landscape, payers, employers, integrated delivery networks (IDNs)/hospital systems have overlapping and distinct costs. All stakeholders experience direct medical costs; however, non-medical costs for CRC program administration are not usually attributed to payers in the US. Due to the age range of individuals eligible for recommended CRC screening, a payer perspective should include a mixed population of both Commercial and Medicare beneficiaries. An employer perspective, however, should assess the impact of CRC screening only in the age range of employed persons and should include productivity loss due to work time foregone for elected colonoscopy screening. Furthermore, due to the frequent migration from health plan to health plan in the US, a CRC screening economic model should adopt a more limited time horizon than lifetime. The perspective of the healthcare delivery system should incorporate direct non-medical costs (e.g. patient navigation and support) and indirect costs (e.g. administration and program management). Another limitation to the practical application of existing US CRC screening economic models is the assumption that patients choose the same screening modality throughout their lifetimes. With multiple screening options at varying frequencies (from 1-10 years) and degrees of invasiveness (from a mailed stool sample to a medical procedure requiring sedation), costing frameworks should reflect the possibility that patients switch screening modalities. We propose a framework for evaluating total costs and health benefits of CRC screening to payers, IDNs/hospital systems and employers that incorporates these stakeholder-specific cost perspectives.

PRS28 THE COST-EFFECTIVENESS OF IL-5 INHIBITORS FOR PERSONS WITH EOSINOPHILIC ASTHMA

The study assessed the cost-effectiveness of IL-5 inhibitors (mepolizumab, reslizumab, and benralizumab) vs. standard of care (SoC) in patients with severe eosinophilic asthma. A Markov model with a payer perspective was used to compare the costs and quality-adjusted life years (QALYs) of IL-5 inhibitors versus SoC alone. The model adopted a cycle length of two weeks with three primary health states over a lifetime horizon (5 years): an asthma non-exacerbation state, asthma exacerbation state (three subcategories: asthma-related event requiring OCS burst; asthma-related emergency department visit; or asthma-related hospitalization), and death. The population was adult patients (≥12 years) with severe eosinophilic asthma (eosinophils ≥300 cells/μL) based on the Global Initiative for Asthma (GINA) steps 4/5 who had experienced at least three exacerbations in the preceding year. Model inputs were obtained from individual patient-level data from two 52-week randomized controlled trials of reslizumab (NCT01287039/ NCT01285323), 32-week RCT of mepolizumab (NCT01691521), and two identical RCTs for benralizumab (NCT01928771/ NCT01914757). Drug costs were based on REDBOOK WAC. Cost and utility values were obtained from previous mepolizumab ICER review. The outcome of interest was incremental cost-effectiveness ratio (ICER), expressed as cost per QALYs gained using 3% discount rate and 2018 currency value. Both deterministic and probabilistic sensitivity analyses were performed. Treatment with mepolizumab, benralizumab, reslizumab were all associated with increased cost of ($493,302.14), ($534,914.29), ($590,851.60), respectively as compared with SoC. These therapies were associated with improved QALYs of 2.81, 2.90, 2.87 respectively, compared with SoC alone, resulting ICER values of $175,271, $184,158, $205,538 per QALY gained, respectively for mepolizumab, benralizumab, and reslizumab. For patients with high eosinophilic asthma, treatment with IL-5 inhibitors as compared to SoC was found to have ICER values that exceed $150,000/QALY. However, these treatments resulted in substantial QALY gains over a fairly limited time horizon.

Detecting Indicators for Startup Business Success: Sentiment Analysis Using Text Data Mining

The main aim of this study is to identify the key factors in User Generated Content (UGC) on the Twitter social network for the creation of successful startups, as well as to identify factors for sustainable startups and business models. New technologies were used in the proposed research methodology to identify the key factors for the success of startup projects. First, a Latent Dirichlet Allocation (LDA) model was used, which is a state-of-the-art thematic modeling tool that works in Python and determines the database topic by analyzing tweets for the #Startups hashtag on Twitter (n = 35.401 tweets). Secondly, a Sentiment Analysis was performed with a Supervised Vector Machine (SVM) algorithm that works with Machine Learning in Python. This was applied to the LDA results to divide the identified startup topics into negative, positive, and neutral sentiments. Thirdly, a Textual Analysis was carried out on the topics in each sentiment with Text Data Mining techniques using Nvivo software. This research has detected that the topics with positive feelings for the identification of key factors for the startup business success are startup tools, technology-based startup, the attitude of the founders, and the startup methodology development. The negative topics are the frameworks and programming languages, type of job offers, and the business angels’ requirements. The identified neutral topics are the development of the business plan, the type of startup project, and the incubator’s and startup’s geolocation. The limitations of the investigation are the number of tweets in the analyzed sample and the limited time horizon. Future lines of research could improve the methodology used to determine key factors for the creation of successful startups and could also study sustainable issues.

Use of Shared-Mobility Services to Accomplish Emergency Evacuation in Urban Areas via Reduction in Intermediate Trips—Case Study in Xi’an, China

Under no-notice evacuation scenarios with limited time horizons, the effectiveness of evacuation can be negatively impacted by intermediate trips that are made by family members and the identification of vulnerable populations. The emergence of shared-mobility companies, such as Uber and DiDi, can be considered as a potential means to address above-mentioned concerns. The proposed study explores the utility of shared-mobility services under emergency-evacuation scenarios and makes recommendations to relevant bodies that are based on the obtained and they are discussed herein. The study investigates attitudes of the public, experts, and drivers towards the use of shared-mobility resources during emergency evacuations based on a stated preference survey. Results of questionnaires, driver interviews, and face-to-face expert interviews have been analyzed to validate the feasibility and identify potential problems of leveraging shared-mobility services during evacuation response, especially in metropolitan areas wherein such services are already ubiquitous. Numerical simulations have been performed to quantify potential improvements in the total trip distance and number of evacuees after incorporating the use of shared mobility into emergency-response operations. However, despite the observed improvement in emergency efficiency, certain realistic roadblocks must be overcome. Realization of the proposed objective heavily depends on actionable policy recommendations, provided herein as a reference for the government, emergency management agencies, and shared-mobility companies.

Health economic aspects of late preterm and early term birth

Despite an increasing body of knowledge on the adverse clinical sequelae associated with late preterm birth and early term birth, little is known about their economic consequences or the cost-effectiveness of interventions aimed at their prevention or alleviation of their effects. This review assesses the health economic evidence surrounding late preterm and early term birth. Evidence is gathered on hospital resource use associated with late preterm and early term birth, economic costs associated with late preterm and early term birth, and economic evaluations of prevention and treatment strategies. The article highlights the limited perspective and time horizon of most studies of economic costs in this area; the limited evidence surrounding health economic aspects of early term birth; the gaps in current knowledge; and it discusses directions for future research in this area, including the need for validated tools for measuring preference-based health-related quality-of-life outcomes in infants that will aid cost-effectiveness-based decision-making.

Modelling and solving the integrated inventory-location-routing problem in a multi-period and multi-perishable product supply chain with uncertainty: Lagrangian relaxation algorithm

In this article a three-echelon supply chain, consisting of a supplier, a number of distribution centers (DCs), and a number of retailers (customers) is modeled in form of the integrated inventory- location – routing problem (ILRP), in a way that perishable products are delivered to the customers in a limited time horizon, consisting of several time periods. The retailers’ demand is stochastic and follows normal distribution with certain mean and standard deviation. The transportation fleet is heterogeneous, and distribution centers use a timetable, which will prevent interference of the vehicles operation and also allocation of a vehicle to more than one distribution center in each time period. Lagrangian Relaxation Method is used to solve the resulted model and determine the lower bound; and a heuristic algorithm is provided to feasibilize the result of the Lagrangian Relaxation Algorithm and determine the upper bound.

The Use of Decision-Analytic Models in Atopic Eczema: A Systematic Review and Critical Appraisal.

The objective of this systematic review was to identify and assess the quality of published economic decision-analytic models within atopic eczema against best practice guidelines, with the intention of informing future decision-analytic models within this condition. A systematic search of the following online databases was performed: MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, Cochrane Database of Systematic Reviews, NHS Economic Evaluation Database, EconLit, Scopus, Health Technology Assessment, Cost-Effectiveness Analysis Registry and Web of Science. Papers were eligible for inclusion if they described a decision-analytic model evaluating both the costs and benefits associated with an intervention or prevention for atopic eczema. Data were extracted using a standardised form by two independent reviewers, whilst quality was assessed using the model-specific Philips criteria. Twenty-four models were identified, evaluating either preventions (n=12) or interventions (n=12): 14 reported using a Markov modelling approach, four utilised decision trees and one a discrete event simulation, whilst five did not specify the approach. The majority, 22 studies, reported that the intervention was dominant or cost effective, given the assumptions and analytical perspective taken. Notably, the models tended to be short-term (16 used a time horizon of ≤1 year), often providing little justification for the limited time horizon chosen. The methodological and reporting quality of the studies was generally weak, with only seven studies fulfilling more than 50% of their applicable Philips criteria. This is the first systematic review of decision models in eczema. Whilst the majority of models reported favourable outcomes in terms of the cost effectiveness of the new intervention, the usefulness of these findings for decision-making is questionable. In particular, there is considerable scope for increasing the range of interventions evaluated, for improving modelling structures and reporting quality.

Profits from Peace: The Political Economy of Power-Sharing and Corruption

Summary Does power-sharing drive corruption in post-conflict countries? We conceptualize government elites in any post-conflict situation as rent-seeking agents who need to ensure the support of their key constituencies to remain in power. Power-sharing institutions—especially cabinet-level, executive power-sharing institutions—systematically shape these rent-seeking motives. Power-sharing cabinets create political coalitions dominated by small circles of government and rebel elites with direct access to state resources and low levels of loyalty toward the government leader. Also, the provisional nature of many power-sharing institutions increases rent-seeking incentives: facing a limited time horizon in office, rent-seeking elites within the power-sharing coalition are likely to capture as many rents as possible before they have to leave office. Thus, post-conflict countries with power-sharing institutions should exhibit higher aggregated levels of rent-seeking measured as the level of corruption in a country. In a statistical analysis of all post-conflict situations during 1996–2010, we find that power-sharing cabinets substantively increase corruption in post-conflict countries and that this effect is stronger in the presence of natural resource rents. These findings add quantitative evidence to the debate about drivers of post-conflict corruption. Moreover, they highlight a trade-off between short-term stability and long-term negative effects of corruption for post-conflict political and economic development.