scholarly journals Moving towards a reliable HIV incidence test – current status, resources available, future directions and challenges ahead

2016 ◽  
Vol 145 (5) ◽  
pp. 925-941 ◽  
Author(s):  
G. MURPHY ◽  
C. D. PILCHER ◽  
S. M. KEATING ◽  
R. KASSANJEE ◽  
S. N. FACENTE ◽  
...  
Keyword(s):  
Performance Metrics ◽  
Critical Path ◽  
Population Level ◽  
Current Status ◽  
Hiv Incidence ◽  
Recent Infection ◽  
Novel Approach ◽  
Product Profile ◽  
And Performance ◽  
The Impact

SUMMARYIn 2011 the Incidence Assay Critical Path Working Group reviewed the current state of HIV incidence assays and helped to determine a critical path to the introduction of an HIV incidence assay. At that time the Consortium for Evaluation and Performance of HIV Incidence Assays (CEPHIA) was formed to spur progress and raise standards among assay developers, scientists and laboratories involved in HIV incidence measurement and to structure and conduct a direct independent comparative evaluation of the performance of 10 existing HIV incidence assays, to be considered singly and in combinations as recent infection test algorithms. In this paper we report on a new framework for HIV incidence assay evaluation that has emerged from this effort over the past 5 years, which includes a preliminary target product profile for an incidence assay, a consensus around key performance metrics along with analytical tools and deployment of a standardized approach for incidence assay evaluation. The specimen panels for this evaluation have been collected in large volumes, characterized using a novel approach for infection dating rules and assembled into panels designed to assess the impact of important sources of measurement error with incidence assays such as viral subtype, elite host control of viraemia and antiretroviral treatment. We present the specific rationale for several of these innovations, and discuss important resources for assay developers and researchers that have recently become available. Finally, we summarize the key remaining steps on the path to development and implementation of reliable assays for monitoring HIV incidence at a population level.

scholarly journals How do you measure up? Methods to assess linkage quality

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Anna Ferrante ◽  
James Boyd ◽  
Sean Randall ◽  
Adrian Brown ◽  
James Semmens
Keyword(s):  
Record Linkage ◽  
Service Use ◽  
Performance Metrics ◽  
Population Level ◽  
Additional Information ◽  
Linkage Quality ◽  
Health And Disease ◽  
The Impact ◽  
Quality Process

ABSTRACT ObjectivesRecord linkage is a powerful technique which transforms discrete episode data into longitudinal person-based records. These records enable the construction and analysis of complex pathways of health and disease progression, and service use. Achieving high linkage quality is essential for ensuring the quality and integrity of research based on linked data. The methods used to assess linkage quality will depend on the volume and characteristics of the datasets involved, the processes used for linkage and the additional information available for quality assessment. This paper proposes and evaluates two methods to routinely assess linkage quality. ApproachLinkage units currently use a range of methods to measure, monitor and improve linkage quality; however, no common approach or standards exist. There is an urgent need to develop “best practices” in evaluating, reporting and benchmarking linkage quality. In assessing linkage quality, of primary interest is in knowing the number of true matches and non-matches identified as links and non-links. Any misclassification of matches within these groups introduces linkage errors. We present efforts to develop sharable methods to measure linkage quality in Australia. This includes a sampling-based method to estimate both precision (accuracy) and recall (sensitivity) following record linkage and a benchmarking method - a transparent and transportable methodology to benchmark the quality of linkages across different operational environments. ResultsThe sampling-based method achieved estimates of linkage quality that were very close to actual linkage quality metrics. This method presents as a feasible means of accurately estimating matching quality and refining linkages in population level linkage studies. The benchmarking method provides a systematic approach to estimating linkage quality with a set of open and shareable datasets and a set of well-defined, established performance metrics. The method provides an opportunity to benchmark the linkage quality of different record linkage operations. Both methods have the potential to assess the inter-rater reliability of clerical reviews. ConclusionsBoth methods produce reliable estimates of linkage quality enabling the exchange of information within and between linkage communities. It is important that researchers can assess risk in studies using record linkage techniques. Understanding the impact of linkage quality on research outputs highlights a need for standard methods to routinely measure linkage quality. These two methods provide a good start to the quality process, but it is important to identify standards and good practices in all parts of the linkage process (pre-processing, standardising activities, linkage, grouping and extracting).

Wind Catcher Technology: The Impact of Tower Cross Section and Turbine on Wind Power Harnessing

2019 ◽  
Author(s):  
Jonathan C. Corbett ◽  
Navid Goudarzi ◽  
Mohammadamin Sheikhshahrokhdehkordi
Keyword(s):  
Wind Power ◽  
Wind Turbines ◽  
Cross Sections ◽  
Natural Ventilation ◽  
Performance Metrics ◽  
Urban Environments ◽  
Ducted Turbine ◽  
And Performance ◽  
Turbine Design ◽  
The Impact

Abstract This research explores utilizing distributed wind turbines in the built environment computationally. The targeted wind turbine design is an unconventional ducted turbine, called Wind Tower technology that its operation and performance metrics have been studied in earlier works in the team. Wind Tower is an established architectural technology that operates by catching wind and directing it into buildings, providing natural ventilation to support HVAC systems, and thus reducing cooling costs in urban environments. Wind power has long struggled to meet expectations in built (urban) environments. By combining wind towers at different cross sections with wind turbines, one might develop a device which provides natural ventilation and produces power in spite of a hostile wind environment. The preliminary results suggest that the maximum potential for a wind tower-turbine combination appears to be 700-1.46 kW under idealized conditions with a 4 m/s site dominant wind speed. This suggests that wind towers might be viable for power harvesting in both remote and grid connected regions. Further analysis suggested that additional turbine performance enhancements are needed to bring the turbine real power production closer to that ideal.

The impact of modelling decisions in hydrological modelling

2021 ◽  
Author(s):  
Janneke Remmers ◽  
Ryan Teuling ◽  
Lieke Melsen
Keyword(s):  
Scientific Reasoning ◽  
Performance Metrics ◽  
Expert Knowledge ◽  
Modelling Framework ◽  
Modelling Environment ◽  
And Performance ◽  
Definition Of ◽  
The Impact ◽  
Modular Modelling ◽  
Modelling Process

<p>Scientific hydrological modellers make multiple decisions during the modelling process, e.g. related to the calibration period and performance metrics. These decisions affect the model results differently. Modelling decisions can refer to several steps in the modelling process. In this project, modelling decisions refer to the decisions made during the whole modelling process, not just the definition of the model structure. Each model output is a hypothesis of the reality; it is an interpretation of the real system underpinned by scientific reasoning and/or expert knowledge. Currently, there is a lack of knowledge and understanding about which modelling decisions are taken and why they are taken. Consequently, the influence of modelling decisions is unknown. Quantifying this influence, which is done in this study, can raise awareness among scientists. This study is based on analysis of interviews with scientific hydrological modellers, thus taking actual practices into account. Different modelling decisions were identified from the interviews, which are subsequently implemented and evaluated in a controlled modelling environment, in our case the modular modelling framework Raven. The variation in the results is analysed to determine which decisions affect the results and how they affect the results. This study pinpoints what aspects are important to consider in studying modelling decisions, and can be an incentive to clarify and improve modelling procedures.</p>

scholarly journals Exogenous re-infection and the dynamics of tuberculosis epidemics: local effects in a network model of transmission

2006 ◽  
Vol 4 (14) ◽  
pp. 523-531 ◽  
Author(s):  
Ted Cohen ◽  
Caroline Colijn ◽  
Bryson Finklea ◽  
Megan Murray
Keyword(s):  
Network Model ◽  
Disease Transmission ◽  
Control Strategies ◽  
Disease Incidence ◽  
Infected Individual ◽  
Population Level ◽  
Recent Infection ◽  
Tb Control ◽  
Relative Contribution ◽  
The Impact

Infection with Mycobacterium tuberculosis leads to tuberculosis (TB) disease by one of the three possible routes: primary progression after a recent infection; re-activation of a latent infection; or exogenous re-infection of a previously infected individual. Recent studies show that optimal TB control strategies may vary depending on the predominant route to disease in a specific population. It is therefore important for public health policy makers to understand the relative frequency of each type of TB within specific epidemiological scenarios. Although molecular epidemiologic tools have been used to estimate the relative contribution of recent transmission and re-activation to the burden of TB disease, it is not possible to use these techniques to distinguish between primary disease and re-infection on a population level. Current estimates of the contribution of re-infection therefore rely on mathematical models which identify the parameters most consistent with epidemiological data; these studies find that exogenous re-infection is important only when TB incidence is high. A basic assumption of these models is that people in a population are all equally likely to come into contact with an infectious case. However, theoretical studies demonstrate that the social and spatial structure can strongly influence the dynamics of infectious disease transmission. Here, we use a network model of TB transmission to evaluate the impact of non-homogeneous mixing on the relative contribution of re-infection over realistic epidemic trajectories. In contrast to the findings of previous models, our results suggest that re-infection may be important in communities where the average disease incidence is moderate or low as the force of infection can be unevenly distributed in the population. These results have important implications for the development of TB control strategies.

scholarly journals Gene-by-environment interactions in agricultural pest management: population effects on diet-Bt interactions in a caterpillar

2020 ◽  
Author(s):  
Carrie Deans ◽  
Gregory Sword ◽  
Spencer Behmer ◽  
Eric Burkness ◽  
Marianne Pusztai-Carey ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Control Strategies ◽  
Laboratory Strain ◽  
Population Level ◽  
Nutrient Content ◽  
Pest Species ◽  
Nutrient Regulation ◽  
Cry Toxin ◽  
And Performance ◽  
The Impact

AbstractGiven that plant nutrient content is both spatially and temporally dynamic (Lenhart et al., 2015; Deans et al., 2016, 2018), insect herbivores are exposed to an incredible amount of nutritional variability. This variability can constrain insects to feeding on sub-optimal resources, but it can also provide an opportunity for insects to regulate their intake of specific nutrients to obtain an optimal balance. Nutrient regulation has implications for pest control strategies in agricultural systems, as the nutritional state of pest species may impact their susceptibility to insecticides. Deans et al. (2017) showed that diet macronutrient balance has significant effects on the susceptibility of Helicoverpa zea larvae to Cry1Ac, an endotoxin expressed in transgenic Bt crops. This was demonstrated using a highly inbred laboratory strain of H. zea, limiting the applicability of these results to field populations that encompass greater genetic diversity. In this study, we assessed the impact of field-relevant macronutrient variability on the efficacy of two Bt endotoxins, Cry1Ab and Cry1Ac, using three field populations collected from different geographic regions. This was done to further understand the impact of nutritional variability on Bt susceptibility and also to determine the relevance of these effects in the field. While we saw limited differences in Cry susceptibility across populations, dietary effects were highly variable. Across populations there were distinct population-level differences in the interactions between Cry concentration and diet, the type of Cry toxin impacted by diet, and the treatment diet that produced optimal survival and performance. These results show that nutrition can have strong impacts on Bt susceptibility but also that these impacts are strongly affected by genetic background in H. zea. To accurately assess Bt susceptibility in the field, including resistance monitoring, bioassay methods should incorporate the appropriate nutritional parameters and be as localized as possible.

Assessing the Impact of Aviation System Performance by Using Airline Cost Functions

2000 ◽  
Vol 1703 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Mark Hansen ◽  
David Gillen ◽  
Reza Djafarian-Tehrani
Keyword(s):  
Performance Metrics ◽  
Factor Model ◽  
Cost Savings ◽  
Cost Functions ◽  
Average Delay ◽  
Multifactor Models ◽  
Important Benefit ◽  
Domestic Airlines ◽  
And Performance ◽  
The Impact

The manner in which changes in the performance of the U.S. National Airspace System (NAS) affect carrier costs is examined. The methodology includes estimation of airline cost functions that contain NAS performance metrics as arguments, using quarterly data for 10 U.S. domestic airlines. The primary interest is in the impact of delay on cost performance, and performance metrics that vary by airline and quarter are developed. The potentially large number of metrics are reduced by applying factor analysis to seven underlying variables, including average delay, delay variance, and the proportion of flights that are cancelled. The analysis reveals that variations in the seven variables can be adequately captured by three or fewer factors. The three factors used correspond to “delay,” “variability,” and “disruption,” the last two of which are merged into a single “irregularity” factor in the two-factor model. When used as arguments in an airline cost function, the “disruption” factor is found to be a significant contributor to airline costs in the three-factor model, as is the “irregularity” factor in the two-factor model. No significant effect is found for the delay factor in the multifactor models. These results challenge the prevailing assumption that delay reduction is the most important benefit from investments in NAS capital and operations rules. The carrier cost savings that would result from improved NAS performance levels are estimated, and these are compared with previously published estimates.

scholarly journals Cohort profile: l’Actuel Pre-Exposure Prophylaxis (PrEP) Cohort study in Montreal, Canada

BMJ Open ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. e028768 ◽  
Author(s):  
Zoë R Greenwald ◽  
Mathieu Maheu-Giroux ◽  
Jason Szabo ◽  
Judith Alexia B Robin ◽  
Michel Boissonnault ◽  
...  
Keyword(s):  
Population Level ◽  
Hiv Infections ◽  
Health Clinic ◽  
Moderate Increase ◽  
Hiv Incidence ◽  
Sexually Transmitted ◽  
Before And After ◽  
Exposure Prophylaxis ◽  
The Impact

PurposeThel’Actuel PrEP Cohortwas established to monitor the uptake, effectiveness, safety and changes in sexual risk behaviours among individuals receiving pre-exposure prophylaxis (PrEP) for the prevention of HIV. This prospective dynamic cohort is based at Clinique médicale l’Actuel, a large sexual health clinic located in Montreal, Canada.ParticipantsSince the cohort inception in January of 2013 through June 2018, 2156 individuals consulted for PrEP as participants in the l’Actuel PrEP Cohort. Median age was 35 years (IQR: 29–44 years) and the majority (96%) were men who have sex with men. Among 1551 individuals who initiated PrEP care, the median duration of follow-up was 9.2 months (IQR: 3.7–19.6), with substantial variation based on year of cohort entry. Thel’Actuel PrEP Cohortcontains both daily and intermittent ‘on-demand’ PrEP users and has the largest reported population of intermittent PrEP users (n=406) in North America.Findings to dateNo incident HIV infections have occurred among individuals using PrEP over 1637 person-years of follow-up. However, retention in PrEP care is essential as three individuals who discontinued PrEP subsequently acquired HIV, translating to an HIV incidence of 3.9 cases per 100 person-years (95% CI: 1.3 to 12.1). Among a sample of participants with 1 year of follow-up before and after PrEP initiation (n=109), a moderate increase in sexually transmitted infections was observed following PrEP start.Future plansThel’Actuel PrEP Cohortcontinues to grow with new participants starting PrEP monthly and extended follow-up for existing users. The cohort data will be used for ongoing monitoring of PrEP and for population-level modelling of the impact of PrEP on HIV incidence in Montreal.

scholarly journals Designing Aedes (Diptera: Culicidae) Mosquito Traps: The Evolution of the Male Aedes Sound Trap by Iterative Evaluation

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 388
Author(s):  
Kyran M. Staunton ◽  
Jianyi Liu ◽  
Michael Townsend ◽  
Mark Desnoyer ◽  
Paul Howell ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Developmental Process ◽  
Control Measures ◽  
Adult Males ◽  
Product Profile ◽  
Catch Rates ◽  
And Performance ◽  
High Level ◽  
Male Specific ◽  
The Impact

Effective surveillance of Aedes aegypti (Linnaeus, Diptera: Culicidae) is critical to monitoring the impact of vector control measures when mitigating disease transmission by this species. There are benefits to deploying male-specific traps, particularly when a high level of catch-specificity is desired. Here, the rationale behind the developmental process of an entirely new trap which uses a sound lure to capture male Ae. aegypti, the male Aedes sound trap (MAST), is presented as a target product profile with findings from developmental trials of key trap components and performance. Trial results suggest that the presence of a black base associated with the trap influenced male catches as did variations in size of this base, to a degree. Trap entrance shape didn’t influence catch rates, but entrance size did. No significant differences in catch rates were found when sound lures were set to intermittent or continuous playbacks, at volumes between 63–74 dB or frequencies of 450 Hz compared to 500 Hz. Additionally, adult males aged 3 days post-eclosion, were less responsive to sound lures set to 500 Hz than those 4 or 6 days old. Lastly, almost no males were caught when the MAST directly faced continual winds of 1.5 ms−1, but males were captured at low rates during intermittent winds, or if the trap faced away from the wind. The developmental process to optimising this trap is applicable to the development of alternate mosquito traps beyond Aedes sound traps and provides useful information towards the improved surveillance of these disease vectors.

scholarly journals Delivering on Purpose

2021 ◽  
pp. 113-129
Author(s):  
Yassine El Ouarzazi
Keyword(s):  
Performance Metrics ◽  
Step Process ◽  
Baseline Performance ◽  
Self Interest ◽  
The Creation ◽  
And Performance ◽  
The Impact ◽  
Pain Points

Chapter 8 describes the process of ecosystem orchestration in more detail. It sets out an eight-step process around: (a) establishing a purpose, (b) designing metrics that measure the purpose, (c) identifying the relevant stakeholders, (d) mapping their objectives, capabilities, relationships, and pain points (i.e. problems), (e) selecting the pain points in the ecosystem that the organization should address, (f) measuring the baseline performance metrics before the intervention, (g) identifying, testing, and implementing the interventions to address the pain points, and (h) measuring the impact of the interventions on purpose and performance. The chapter emphasizes that the process of ecosystem orchestration involves the company placing the interests of the ecosystem and the ecosystem’s purpose against the company’s own self-interest at the centre of its own purpose. In so doing, the company should embrace the creation of mutuality of benefits not for enlightened self-interest but on a commitment to delivering the ecosystem purpose.

scholarly journals A Scoping Review: The Impact of Housing Systems and Environmental Features on Beef Cattle Welfare

Animals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 565 ◽  
Author(s):  
Rachel M. Park ◽  
Margaret Foster ◽  
Courtney L. Daigle
Keyword(s):  
Beef Cattle ◽  
Scoping Review ◽  
Environmental Enrichment ◽  
Performance Metrics ◽  
Feedlot Cattle ◽  
Housing Systems ◽  
Advantages And Disadvantages ◽  
Environmental Features ◽  
And Performance ◽  
The Impact

Housing systems and environmental features can influence beef cattle welfare. To date, little information has been synthesized on this topic. The aim of this scoping review was to examine the relationship between housing and welfare status, so that beef cattle producers and animal scientists can make informed decisions regarding how their housing choices could impact beef cattle welfare. Housing features were categorized by floor type, space allowance and shade availability, as well as the inclusion of enrichment devices or ventilation features. Evaluation of space allowances across feedlot environments determined behavioral and production benefits when cattle were housed between 2.5 m2 to 3.0 m2 per animal. Over 19 different flooring types were investigated and across flooring types; straw flooring was viewed most favorably from a behavioral, production and hygiene standpoint. Veal calves experience enhanced welfare (e.g., improved behavioral, physiological, and performance metrics) when group housed. There is evidence that the implementation of progressive housing modifications (e.g., shade, environmental enrichment) could promote the behavioral welfare of feedlot cattle. This review presents the advantages and disadvantages of specific housing features on the welfare of beef cattle.

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