42 results on '"Richardus, J"'
Search Results
2. Determining target populations for leprosy prophylactic interventions: a hotspot analysis in Indonesia
- Author
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Taal, A. T., Blok, D. J., Handito, A., Wibowo, S., Sumarsono, Wardana, A., Pontororing, G., Sari, D. F., van Brakel, W. H., Richardus, J. H., and Prakoeswa, C. R. S.
- Published
- 2022
- Full Text
- View/download PDF
3. Participation of private providers in the National TB Programme in South India
- Author
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Meundi, A. D., primary and Richardus, J. H., additional
- Published
- 2023
- Full Text
- View/download PDF
4. The effect of a hand hygiene intervention on infections in residents of nursing homes: a cluster randomized controlled trial
- Author
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Teesing, G. R., Richardus, J. H., Nieboer, D., Petrignani, M., Erasmus, V., Verduijn-Leenman, A., Schols, J. M. G. A., Koopmans, M. P. G., Vos, M. C., and Voeten, H. A. C. M.
- Published
- 2021
- Full Text
- View/download PDF
5. Development of a TB vaccine trial site in Africa and lessons from the Ebola experience
- Author
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Kaguthi, G., Nduba, V., Rabuogi, P., Okelloh, D., Ouma, S. G., Blatner, G., Gelderbloem, S., Mitchell, Ellen M. H., Scott, Cherise P., Verver, S., Hawkridge, T., de Steenwinkel, J. E. M., Laserson, K. F., and Richardus, J. H.
- Published
- 2020
- Full Text
- View/download PDF
6. Improving hand hygiene compliance in child daycare centres : a randomized controlled trial
- Author
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ZOMER, T. P., ERASMUS, V., LOOMAN, C. W., VAN BEECK, E. F., TJON-A-TSIEN, A., RICHARDUS, J. H., and VOETEN, H. A. C. M.
- Published
- 2016
7. A hand hygiene intervention to reduce infections in child daycare : a randomized controlled trial
- Author
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ZOMER, T. P., ERASMUS, V., LOOMAN, C. W., TJON-A-TSIEN, A., VAN BEECK, E. F., DE GRAAF, J. M., VAN BEECK, A. H. E., RICHARDUS, J. H., and VOETEN, H. A. C. M.
- Published
- 2015
8. A successive censoring algorithm for a system of connected LDQBD-processes
- Author
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Ahmad Al Hanbali, Richardus J. Boucherie, Jan-Kees van Ommeren, Niek Baër, Stochastic Operations Research, and Mathematics of Operations Research
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Stationary distribution ,Successive censoring algorithm ,Markov chain ,Matrix analytic methods ,Steady state analysis ,Censoring (clinical trials) ,Theory of computation ,General Decision Sciences ,Exact aggregation/disaggregation ,Connected level dependent QBD-processes ,Management Science and Operations Research ,Algorithm ,Mathematics - Abstract
We consider a Markov Chain in which the state space is partitioned into sets where both transitions within sets and between sets have a special structure. Transitions within each set constitute a finite level dependent quasi-birth-and-death-process (LDQBD), and transitions between sets are restricted to six types of transitions. These latter types are needed to preserve the sets structure in the reduction step of our algorithm. Specifically, we present a successive censoring algorithm, based on matrix analytic methods, to obtain the stationary distribution of this system of connected LDQBD-processes.
- Published
- 2021
9. Determining target populations for leprosy prophylactic interventions:a hotspot analysis in Indonesia
- Author
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Taal, A. T., Blok, D. J., Handito, A., Wibowo, S., Sumarsono, Wardana, A., Pontororing, G., Sari, D. F., van Brakel, W. H., Richardus, J. H., Prakoeswa, C. R.S., Taal, A. T., Blok, D. J., Handito, A., Wibowo, S., Sumarsono, Wardana, A., Pontororing, G., Sari, D. F., van Brakel, W. H., Richardus, J. H., and Prakoeswa, C. R.S.
- Abstract
Background: Leprosy incidence remained at around 200,000 new cases globally for the last decade. Current strategies to reduce the number of new patients include early detection and providing post-exposure prophylaxis (PEP) to at-risk populations. Because leprosy is distributed unevenly, it is crucial to identify high-risk clusters of leprosy cases for targeting interventions. Geographic Information Systems (GIS) methodology can be used to optimize leprosy control activities by identifying clustering of leprosy cases and determining optimal target populations for PEP. Methods: The geolocations of leprosy cases registered from 2014 to 2018 in Pasuruan and Pamekasan (Indonesia) were collected and tested for spatial autocorrelation with the Moran’s I statistic. We did a hotspot analysis using the Heatmap tool of QGIS to identify clusters of leprosy cases in both areas. Fifteen cluster settings were compared, varying the heatmap radius (i.e., 500 m, 1000 m, 1500 m, 2000 m, or 2500 m) and the density of clustering (low, moderate, and high). For each cluster setting, we calculated the number of cases in clusters, the size of the cluster (km2), and the total population targeted for PEP under various strategies. Results: The distribution of cases was more focused in Pasuruan (Moran’s I = 0.44) than in Pamekasan (0.27). The proportion of total cases within identified clusters increased with heatmap radius and ranged from 3% to almost 100% in both areas. The proportion of the population in clusters targeted for PEP decreased with heatmap radius from > 100% to 5% in high and from 88 to 3% in moderate and low density clusters. We have developed an example of a practical guideline to determine optimal cluster settings based on a given PEP strategy, distribution of cases, resources available, and proportion of population targeted for PEP. Conclusion: Policy and operational decisions related to leprosy control programs can be guided by a hotspot analysis which aid
- Published
- 2022
10. O17.6 Risk factors for STI versus testing rates in a Dutch multicultural area: opportunities for increasing sexual health care accessibility?
- Author
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Twisk, D, primary, Meima, A, additional, Richardus, J, additional, and Götz, H, additional
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- 2021
- Full Text
- View/download PDF
11. Association of environmental surface contamination with hand hygiene and infections in nursing homes:a prospective cohort study
- Author
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Teesing, G. R., de Graaf, M., Petrignani, M., Erasmus, V., Klaassen, C. H.W., Schapendonk, C. M.E., Verduijn-Leenman, A., Schols, J. M.G.A., Vos, M. C., Koopmans, M. P.G., Richardus, J. H., Voeten, H., Teesing, G. R., de Graaf, M., Petrignani, M., Erasmus, V., Klaassen, C. H.W., Schapendonk, C. M.E., Verduijn-Leenman, A., Schols, J. M.G.A., Vos, M. C., Koopmans, M. P.G., Richardus, J. H., and Voeten, H.
- Abstract
Background: Little is known about the presence of infections in nursing home residents, the causative micro-organisms, how hand hygiene (HH) influences the presence of infections in residents, and the extent to which environmental contamination is associated with the incidence of infection among residents. Aims: To establish if environmental contamination can be used as an indicator for HH compliance, and if environmental contamination is associated with the incidence of infection. Methods: Environmental surface samples (ESS) were collected in an exploratory study as part of a HH intervention in 60 nursing homes. ESS results from three distinct surfaces (nurses' station, communal toilet and residents' shared living area) were compared with nurses' HH compliance and the incidence of infection among residents. Real-time polymerase chain reaction assays were used to detect norovirus genogroup I and II, rhinovirus and Escherichia coli. HH compliance was measured by direct observation. The incidence of infection was registered weekly. Findings: Rhinovirus (nurses' station: 41%; toilet: 14%; living area: 29%), norovirus (nurses' station: 18%; toilet: 12%; living area: 16%) and E. coli (nurses' station: 14%; toilet: 58%; living area: 54%) were detected. No significant (P<0.05) associations were found between HH compliance and the presence of micro-organisms. An association was found between E. coli contamination and the incidence of disease in general (P=0.04). No other associations were found between micro-organisms and the incidence of disease. Conclusion: Rhinovirus, norovirus and E. coli were detected on surfaces in nursing homes. No convincing associations were found between environmental contamination and HH compliance or the incidence of disease. This study provides reference data about surface contamination.
- Published
- 2021
12. A two-echelon spare parts network with lateral and emergency shipments: a product-form approximation
- Author
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Geert-Jan van Houtum, Jan-Kees van Ommeren, Richardus J. Boucherie, Judith B. Timmer, Stochastic Operations Research, and Operations Planning Acc. & Control
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Statistics and Probability ,Operations research ,multi-echelon ,Computer science ,0211 other engineering and technologies ,UT-Hybrid-D ,product-form solution ,02 engineering and technology ,Management Science and Operations Research ,Industrial and Manufacturing Engineering ,emergency shipments ,0502 economics and business ,Operations management ,Queue ,Inventory control ,Downtime ,050208 finance ,021103 operations research ,05 social sciences ,Product-form solution ,Erlang (unit) ,Spare part ,Inventory theory ,Spare parts inventory control ,Probability distribution ,Statistics, Probability and Uncertainty - Abstract
We consider a single-item, two-echelon spare parts inventory model for repairable parts for capital goods with high down time costs. The inventory system consists of a central warehouse and multiple local warehouses, from where customers are served, and a central repair facility at an external supplier. When a part fails at a customer, his request for a ready-for-use part is immediately fullled by his local warehouse if it has a part on stock. At the same time, the failed part is sent to the central repair facility for repair. If the local warehouse is out of stock, then, via an emergency shipment, a ready-for-use part is sent from the central warehouse if it has a part on stock. Otherwise, it is sent via a lateral transshipment from another local warehouse or the external supplier. We assume Poisson demand processes, generally distributed leadtimes for replenishments, repairs, and emergency shipments, and a base-stock policy for the inventory control. Because our inventory system is too complex to solve for a steady-state distribution in closed form, we approximate it by a network of Erlang loss queues with so-called hierarchical jump-over blocking. We show that this network has a steady-state distribution in product-form. Further, this steady-state distribution and several relevant performance measures only depend on the distributions for the repair and replenishment lead times via their means (i.e., they are insensitive for the underlying probability distributions). The steady-state distribution in product-form enables an ecient heuristic for the optimization of base-stock levels, resulting in good approximations of the optimal costs.
- Published
- 2018
13. Estimating the potential of collaborating professionals, with an application to the Dutch film industry
- Author
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Esme Lammers, Maarten Bos, Arjan Feenstra, Richardus J. Boucherie, Judith B. Timmer, Niek Baër, and Stochastic Operations Research
- Subjects
Estimation ,Value (ethics) ,Dutch films ,business.industry ,05 social sciences ,UT-Hybrid-D ,Management Science and Operations Research ,Public relations ,Film industry ,GeneralLiterature_MISCELLANEOUS ,Movie theater ,Film performance ,0502 economics and business ,Proposals from collaborations ,Business, Management and Accounting (miscellaneous) ,050207 economics ,Marketing ,business ,Evaluation ,050203 business & management - Abstract
Professionals often collaborate in projects. Some of these projects require funding, so before the collaboration can start a proposal for the project is submitted. This proposal will then be evaluated by a committee. The goal of the committee is to recognise proposals that are likely to be very successful. In this paper, we introduce a new numerical method to estimate the expected potential of a proposal. This method helps in identifying proposals that may turn out to be the most successful. The estimation is derived from the past performances of the professionals involved and takes into account the uncertainty of a contribution of a professional to a proposal. We apply our method to the Dutch film industry. We estimate the potential of proposals for new films released in 2010. The value of a film depends on the number of visitors in cinemas and the artistic prizes won. Our estimates are very good, indicating that past performances of filmmakers provide a very good indication of the potential of their new film. As a by-product of our method, rankings of producers, directors, and screenwriters of Dutch films up to 2011 are obtained.
- Published
- 2018
14. Offload zone patient selection criteria to reduce ambulance offload delay
- Author
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Richardus J. Boucherie, Peter T. Vanberkel, Alix J E Carter, Corine Maartje Laan, Stochastic Operations Research, and Center for Healthcare Operations Improvement and Research
- Subjects
Emergency Medical Services ,021103 operations research ,EWI-27218 ,Computer science ,business.industry ,Offload zone ,Offload delay ,Real-time computing ,0211 other engineering and technologies ,Emergency department overcrowding ,Crew ,Medicine (miscellaneous) ,030208 emergency & critical care medicine ,02 engineering and technology ,Management Science and Operations Research ,Continuous time Markov chain ,03 medical and health sciences ,0302 clinical medicine ,METIS-319440 ,General Health Professions ,Emergency medical services ,business ,IR-102075 ,Computer network - Abstract
Emergency department overcrowding is a widespread problem and often leads to ambulance offload delay. If no bed is available when a patient arrives, the patient has to wait with the ambulance crew. A recent Canadian innovation is the offload zone—an area where multiple patients can wait with a single paramedic–nurse team allowing, the ambulance crew to return to service immediately. Although a reduction in offload delay was anticipated, it was observed that the offload zone is often at capacity. In this study we investigate why this is the case and use a continuous time Markov chain to evaluate how interventions can prevent congestion in the offload zone. Specifically we demonstrate conditions where the offload zone worsens offload delay and conditions where the offload zone can essentially eliminate offload delay.
- Published
- 2016
15. Reducing access times for radiation treatment by aligning the doctor’s schemes
- Author
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Nikky Kortbeek, Ingeborg Aleida Bikker, Richardus J. Boucherie, Rob M. van Os, Stochastic Operations Research, and Center for Healthcare Operations Improvement and Research
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Linear programming ,Operations research ,media_common.quotation_subject ,Medicine (miscellaneous) ,Management Science and Operations Research ,Resource (project management) ,IR-98158 ,Medicine ,media_common.cataloged_instance ,Quality (business) ,Operations management ,Discrete event simulation ,European union ,Linear Programming ,Set (psychology) ,Integer programming ,media_common ,Radiotherapy ,business.industry ,METIS-315013 ,Capacity allocation ,EWI-26429 ,General Health Professions ,business ,Access time ,Simulation - Abstract
Around 40% of cured cancer patients in the European Union are treated with radiotherapy [2]. Delays in cancer treatment are associated with psychological distress and decreased cancer control. To this end, in the Netherlands standards for the access time for radiation treatment are set, which are currently not met in many Dutch oncological centers. The radiotherapy care process (i.e., preparation and treatment) consists of several consecutive stages, possibly related via time constraints. Inadequate capacity allocation may cause large delays, for example due to the capacity allocation of different stages not being aligned, or due to inadequate time division of single resources over different activities. The objective of this study is to increase compliance to access time standards without extending resource capacities, by developing a methodology for optimizing resource capacity allocation in the radiotherapy care process. For radiotherapy, time division of resources over different activities particularly applies to the doctors, who carry out consultations and scan contouring. Time slots for these activities are typically set for each doctor in a cyclic weekly scheme. We develop an integer linear programming (ILP) model to design a weekly doctors’ scheme that minimizes the expected access times of all patient types in the care process and that matches the number of consultation time slots with demand. In several experiments, the quality of the resulting doctors’ schemes is studied via a discrete event simulation model by evaluating the consequences of the schemes in a stochastic environment. Results from a case study in the Academic Medical Center (AMC) in Amsterdam show that the implementation of these schemes may result in a considerable access time reduction. The designed doctor’s schemes are being evaluated for implementation in the AMC.
- Published
- 2015
16. Policy lessons from quantitative modeling of leprosy
- Author
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Medley, G, Blok, D, Crump, R, Hollingsworth, T, Galvani, A, Ndeffo-Mbah, M, Porco, T, Richardus, J, and Public Health
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TRANSMISSION ,diagnosis ,Immunology ,Supplement Articles ,Medical and Health Sciences ,Microbiology ,elimination ,Theoretical ,Models ,MYCOBACTERIUM-LEPRAE ,Leprosy ,Humans ,Disease Eradication ,Science & Technology ,Models, Statistical ,Incidence ,mathematical modeling ,11 Medical And Health Sciences ,Statistical ,Biological Sciences ,06 Biological Sciences ,Models, Theoretical ,BRAZIL ,Infectious Diseases ,Policy ,Life Sciences & Biomedicine ,RC - Abstract
Recent mathematical and statistical modeling of leprosy incidence data provides estimates of the current undiagnosed population and projections of diagnosed cases, as well as ongoing transmission. Furthermore, modeling studies have been used to evaluate the effectiveness of proposed intervention strategies, such as postleprosy exposure prophylaxis and novel diagnostics, relative to current approaches. Such modeling studies have revealed both a slow decline of new cases and a substantial pool of undiagnosed infections. These findings highlight the need for active case detection, particularly targeting leprosy foci, as well as for continued research into innovative accurate, rapid, and cost-effective diagnostics. As leprosy incidence continues to decline, targeted active case detection primarily in foci and connected areas will likely become increasingly important.
- Published
- 2018
17. Chronic hepatitis B and C infections in the Netherlands: estimated prevalence in risk groups and the general population
- Author
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Koopsen, J., primary, van Steenbergen, J. E., additional, Richardus, J. H., additional, Prins, M., additional, Op de Coul, E. L. M., additional, Croes, E. A., additional, Heil, J., additional, Zuure, F. R., additional, and Veldhuijzen, I. K., additional
- Published
- 2019
- Full Text
- View/download PDF
18. Green Wave Analysis in a Tandem of Traffic-Light Intersections
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Oblakova, Anna, Al Hanbali, Ahmad, Boucherie, Richardus J., van Ommeren, Jan C.W., Stochastic Operations Research, and Industrial Engineering & Business Information Systems
- Subjects
fixed traffic-light control ,Mathematics(all) ,green wave ,stochastic model - Abstract
Green waves in urban settings are seen to be beneficial both for the drivers and the environment because they lower delays and reduce pollution. To obtain these benefits, it is important to determine the optimal network parameters, e.g., green splits and offsets, that yield the desired traffic behaviour. We consider two possibilities for network optimization. The first one is minimising the average lost time per vehicle; the second one is maximizing the green wave efficiency. We compare the results with the MAXBAND algorithm, which is used at the design stage of arterial traffic light settings to facilitate green waves. Using our optimisation method, the average delay per vehicle can be reduced by up to 10% and more vehicles can encounter a green wave compared to the MAXBAND approach. The reduction of the average delay for the main stream reaches 20%.
- Published
- 2017
19. Stratified breast cancer follow-up using a partially observable MDP
- Author
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Otten, J.W.M., Witteveen, Annemieke, Vliegen, Ingrid, Siesling, Sabine, Timmer, Judith B., IJzerman, Maarten J., Boucherie, Richardus J., van Dijk, Nico, Department of Business-Society Management, Anesthesiology, and Erasmus MC other
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EWI-27869 ,Schedule ,Pediatrics ,medicine.medical_specialty ,0211 other engineering and technologies ,IR-104507 ,02 engineering and technology ,SDG 3 – Goede gezondheid en welzijn ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,SDG 3 - Good Health and Well-being ,EWI-27869, Partially observable markov decision process, Breast cancer, Optimal policies, IR-104507, Stratified follow-up ,Optimal policies ,Medicine ,Mammography ,Operations management ,021103 operations research ,medicine.diagnostic_test ,business.industry ,Partially observable Markov decision process ,Second primary cancer ,medicine.disease ,Primary tumor ,Cancer registry ,030220 oncology & carcinogenesis ,Stratified follow-up ,Markov decision process ,business ,Partially observable markov decision process - Abstract
Frequency and duration of follow-up for patients with breast cancer is still under discussion. Current follow-up consists of annual mammography for the first five years after treatment and does not depend on the personal risk of developing a locoregional recurrence (LRR) or second primary tumor. Aim of this study is to gain insight in how to allocate resources for optimal and personal follow-up. We formulate a discrete-time Partially Observable Markov Decision Process (POMDP) with a finite horizon in which we aim to maximize the total expected number of quality-adjusted life years (QALYs). Transition probabilities were obtained from data from the Netherlands Cancer Registry (NCR). Twice a year the decision is made whether or not a mammography will be performed. Recurrent disease can be detected by both mammography or women themselves (self-detection). The optimal policies were determined for three risk categories based on differentiation of the primary tumor. Our results suggest a slightly more intensive follow-up for patients with a high risk and poorly differentiated tumor, and a less intensive schedule for the other risk groups.
- Published
- 2017
20. Stochastic dynamic programming for noise load management
- Author
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Meerburg, T.R., Boucherie, Richard, van Kraaij, M.J.A.L., Boucherie, Richardus J., van Dijk, Nico, and Stochastic Operations Research
- Subjects
Mathematical optimization ,Computer science ,Noise load management ,EWI-27919 ,Stochastic programming ,Reduction (complexity) ,Load management ,Noise ,airport ,Stochastic dynamic programming ,State space ,Runway preference list selection ,Runway ,Limit (mathematics) ,Selection (genetic algorithm) - Abstract
Noise load reduction is among the primary performance targets for some airports. For airports with a complex lay-out of runways, runway selection may then be carried out via a preference list, an ordered set of runway combinations such that the higher on the list a runway combination, the better this combination is for reducing noise load. The highest safe runway combination in the list will actually be used. The optimal preference list selection minimises the probability of exceeding the noise load limit at the end of the aviation year. This paper formulates the preference list selection problem in the framework of Stochastic Dynamic Programming that enables determining an optimal strategy for the monthly preference list selection problem taking into account future and unpredictable weather conditions, as well as safety and efficiency restrictions. The resulting SDP has a finite horizon (aviation year), continuous state space (accumulated noise load), time-inhomogeneous transition densities (monthly weather conditions) and one-step rewards zero. For numerical evaluation of the optimal strategy, we have discretised the state space. In addition, to reduce the size of the state space we have lumped into a single state those states that lie outside a cone of states that may achieve the noise load restrictions. Our results indicate that the SDP approach allows for optimal preference list selection taking into account uncertain weather conditions.
- Published
- 2017
21. Exact expected delay and distribution for the fixed-cycle traffic-light model and similar systems in explicit form
- Author
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Oblakova, Anna, Al Hanbali, Ahmad, Boucherie, Richardus J., van Ommeren, Jan C.W., Zijm, Willem H.M., Stochastic Operations Research, and Industrial Engineering & Business Information Systems
- Subjects
roots ,contour integration ,MSC-60J22 ,METIS-317688 ,Fixed-cycle traffic light model ,bulk service queue ,Computer Science::Networking and Internet Architecture ,IR-101081 ,EWI-27174 - Abstract
In this paper we present a new method on how to compute the expectation and distribution of the queue length for a particular class of systems. We apply this method and prove its time-efficiency for models in road traffic such as the fixed-cycle traffic light (FCTL) model and for the bulk-service queue model. We give several generalizations of the FCTL queue, which model right-turns, disruptions of the traffic and uncertainty in departure times. We also consider different ways of green time allocation, which are based on either minimizing the maximum expected delay per vehicle or minimizing the total expected queue length. We compare these methods to proportional allocation.
- Published
- 2016
22. Interview Wim Klein Haneveld en Jan Karel Lenstra: De geschiedenis herhaalt zich
- Author
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Boucherie, Richardus J., Hurink, Johann L., Stochastic Operations Research, and Discrete Mathematics and Mathematical Programming
- Subjects
IR-101011 ,EWI-27107 ,METIS-318474 - Abstract
Het veertigjarig jubileum van de ‘Lunteren Conference on the Mathematics of Operations Research’ vormt de aanleiding voor een interview met Wim Klein Haneveld en Jan Karel Lenstra, die nauw betrokken zijn geweest bij de ontwikkeling van landelijke samenwerking in de mathematische besliskunde. Naast de conferentie is ook het onderwijsprogramma dat wordt verzorgd door het Landelijk Netwerk Mathematische Besliskunde een belangrijk onderdeel van het succes van deze samenwerking. De afweging tussen lokale universitaire en nationale belangen bij het opzetten van dit programma dertig jaar geleden vertoont een grote overeenkomst met de huidige discussie rond Mastermath in het Deltaplan voor de Nederlandse wiskunde. Richard Boucherie en Johann Hurink spraken Wim Klein Haneveld en Jan Karel Lenstra op 29 januari 2016.
- Published
- 2016
23. A two-echelon spare parts network with lateral and emergency shipments: A product-form approximation
- Author
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Boucherie, Richardus J., van Houtum, Geert-Jan, Timmer, Judith B., van Ommeren, Jan C.W., and Stochastic Operations Research
- Subjects
EWI-26712 ,Emergency shipments ,Spare parts inventory control ,IR-99176 ,Multi-echelon ,METIS-315536 ,Product form solution - Abstract
We consider a single-item, two-echelon spare parts inventory model for repairable parts for capital goods with high down time costs. The inventory system consists of a central warehouse and multiple local warehouses, from where customers are served, and a central repair facility at an external supplier. When a part fails at a customer, his request for a ready-for-use part is immediately fullled by his local warehouse if it has a part on stock. At the same time, the failed part is sent to the central repair facility for repair. If the local warehouse is out of stock, then, via an emergency shipment, a ready-for-use part is sent from the central warehouse if it has a part on stock. Otherwise, it is sent via a lateral transshipment from another local warehouse or the external supplier. We assume Poisson demand processes, generally distributed leadtimes for replenishments, repairs, and emergency shipments, and a base-stock policy for the inventory control. Because our inventory system is too complex to solve for a steady-state distribution in closed form, we approximate it by a network of Erlang loss queues with so-called hierarchical jump-over blocking. We show that this network has a steady-state distribution in product-form. Further, this steady-state distribution and several relevant performance measures only depend on the distributions for the repair and replenishment lead times via their means (i.e., they are insensitive for the underlying probability distributions). The steady-state distribution in product-form enables an ecient heuristic for the optimization of base-stock levels, resulting in good approximations of the optimal costs.
- Published
- 2016
24. Newly identified risk factors for MRSA carriage in The Netherlands
- Author
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Lekkerkerk, W. S. N., primary, Haenen, A., additional, van der Sande, M. A. B., additional, Leenstra, T., additional, de Greeff, S., additional, Timen, A., additional, Tjon-a-Tsien, A., additional, Richardus, J. H., additional, van de Sande-Bruinsma, N., additional, and Vos, M. C., additional
- Published
- 2017
- Full Text
- View/download PDF
25. Data retrieval time for energy harvesting wireless sensors
- Author
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Mitici, M.A., Goseling, Jasper, de Graaf, Maurits, Boucherie, Richardus J., and Stochastic Operations Research
- Subjects
data retrieval time ,Energy harvesting ,Computer Science::Networking and Internet Architecture ,EWI-26343 ,IR-97462 ,Wireless Sensor Networks ,phase-type distribution ,METIS-312731 ,Order statistics - Abstract
We consider the problem of retrieving a reliable estimate of an attribute monitored by a wireless sensor network, where the sensors harvest energy from the environment independently, at random. Each sensor stores the harvested energy in batteries of limited capacity. Moreover, provided they have sufficient energy, the sensors broadcast their measurements in a decentralized fashion. Clients arrive at the sensor network according to a Poisson process and are interested in retrieving a fixed number of sensor measurements, based on which a reliable estimate is computed. We show that the time until an arbitrary sensor broadcasts has a phase-type distribution. Based on this result and the theory of order statistics of phase-type distributions, we determine the probability distribution of the time needed for a client to retrieve a reliable estimate of an attribute monitored by the sensor network. We also provide closed-form expression for the retrieval time of a reliable estimate when the capacity of the sensor battery or the rate at which energy is harvested is asymptotically large. In addition, we analyze numerically the retrieval time of a reliable estimate for various sizes of the sensor network, maximum capacity of the sensor batteries and rate at which energy is harvested. These results show that the energy harvesting rate and the broadcasting rate are the main parameters that influence the retrieval time of a reliable estimate, while deploying sensors with large batteries does not significantly reduce the retrieval time.
- Published
- 2015
26. Integral resource capacity planning for inpatient care services based on bed census predictions by hour
- Author
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Richardus J. Boucherie, Ferry H.F. Smeenk, Nikky Kortbeek, Aleida Braaksma, Piet J. M. Bakker, Stochastic Operations Research, Center for Healthcare Operations Improvement and Research, Patient Care Support, and Other departments
- Subjects
Surgical Scheduling ,Medical care units ,Computer science ,Strategy and Management ,0211 other engineering and technologies ,02 engineering and technology ,Management Science and Operations Research ,Bed occupancy ,EWI-25109 ,Management Information Systems ,Unit (housing) ,03 medical and health sciences ,Capacity planning ,Resource (project management) ,Case mix index ,IR-97048 ,Operations management ,Probability ,Marketing ,021103 operations research ,Inpatient care ,030503 health policy & services ,Emergency department ,Bed Occupancy ,Hospitals ,Schedule (workplace) ,MSC-60J99 ,Health service ,0305 other medical science ,METIS-311158 - Abstract
The design and operations of inpatient care facilities are typically largely historically shaped. A better match with the changing environment is often possible, and even inevitable due to the pressure on hospital budgets. Effectively organizing inpatient care requires simultaneous consideration of several interrelated planning issues. Also, coordination with upstream departments like the operating theatre and the emergency department is much-needed. We present a generic analytical approach to predict bed census on nursing wards by hour, as a function of the Master Surgical Schedule and arrival patterns of emergency patients. Along these predictions, insight is gained on the impact of strategic (ie, case mix, care unit size, care unit partitioning), tactical (ie, allocation of operating room time, misplacement rules), and operational decisions (ie, time of admission/discharge). The method is used in the Academic Medical Center Amsterdam as a decision-support tool in a complete redesign of the inpatient care operations.
- Published
- 2015
27. Valuation under randomness of players in coalitions, with an application to the Dutch filmindustry
- Author
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Timmer, Judith B., Boucherie, Richardus J., Lammers, Esme, Baër, Niek, Bos, Maarten, Feenstra, Arjan, and Stochastic Operations Research
- Subjects
Dutch films ,EWI-26081 ,Film performance ,IR-96266 ,Proposals from collaborations ,METIS-312638 ,Evaluation - Abstract
In this paper we introduce a new and objective method to measure the quality of proposals from collaborating professionals. The quality or potential of a professional in a proposal is in uenced by a random environment. We derive a (numerical) value which measures the potential of a proposal by collaborating professionals. Furthermore, we provide the best linear unbiased estimator of the potential of a professional. We apply our method to estimate the values of Dutch films, from collaborating producers and filmmakers, released in 2010. Our method is shown to obtain good results. Furthermore, as a by-product we rank producers, directors and screenwriters of Dutch films up to 2011. These rankings are concluded to be fair.
- Published
- 2015
28. Wiskunde voor de basisschool: speels, verrassend en uitdagend
- Author
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Bloemhof, Jantine, Boucherie, Richardus J., and Stochastic Operations Research
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EWI-26453 ,IR-98364 ,METIS-315029 - Abstract
Het afgelopen jaar waren er twee initiatieven om leerlingen van de basisschool op een vrolijke en ongedwongen manier met wiskunde bezig te laten zijn: de NEMO-tentoonstelling ‘Wereld van vormen’ en de theatervoorstelling ‘Het verhaal van de getallen’ van Maas theater en dans. We hebben het plezier gezien van jonge kinderen bij het werken met de opstellingen in de ‘Wereld van vormen’ en de vrolijke en originele manier waarop in ‘Het verhaal van de getallen’ allerhande wiskundige wetenswaardigheden werden gepresenteerd. Dit was voor Jantine Bloemhof en Richard Boucherie de aanleiding om eens op een rijtje te zetten welke mogelijkheden er op dit moment zijn voor leerlingen op de basisschool om op een aantrekkelijke manier met wiskunde bezig te zijn. Zij geven een korte impressie van de ‘Wereld van vormen’ en van ‘Het verhaal van de getallen’ om aan te geven waarom ze bij jong en oud zo goed vallen en een overzicht van een aantal andere initiatieven en mogelijkheden.
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- 2015
29. Flexible nurse staffing based on hourly bed census predictions
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Richardus J. Boucherie, C.A.J. Burger, Piet J. M. Bakker, Nikky Kortbeek, Aleida Braaksma, Stochastic Operations Research, Center for Healthcare Operations Improvement and Research, Patient Care Support, and Other departments
- Subjects
EWI-25569 ,Economics and Econometrics ,Float (project management) ,Workforce planning ,METIS-312476 ,Inpatient care ,Computer science ,Staffing ,Management Science and Operations Research ,Census ,General Business, Management and Accounting ,Industrial and Manufacturing Engineering ,Unit (housing) ,Variable (computer science) ,Case mix index ,IR-94460 ,Nurse-to-patient ratio ,Operations management ,Float nurse ,Probability - Abstract
Workloads in nursing wards depend highly on patient arrivals and lengths of stay, both of which are inherently variable. Predicting these workloads and staffing nurses accordingly are essential for guaranteeing quality of care in a cost-effective manner. This paper introduces a stochastic method that uses hourly census predictions to derive efficient nurse staffing policies. The generic analytic approach minimizes staffing levels while satisfying so-called nurse-to-patient ratios. In particular, we explore the potential of flexible staffing policies that allow hospitals to dynamically respond to their fluctuating patient population by employing float nurses. The method is applied to a case study of the surgical inpatient clinic of the Academic Medical Center Amsterdam (AMC). This case study demonstrates the method's potential to evaluate the complex interaction between staffing requirements and several interrelated planning issues such as case mix, care unit partitioning and size, as well as surgical block planning. Inspired by the quantitative results, the AMC concluded that implementing this flexible nurse staffing methodology will be incorporated in the redesign of the inpatient care operations in the upcoming years.
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- 2015
30. Kantelen of kapseizen?
- Author
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Boucherie, Richardus J., van Neerven, Jan, and Stochastic Operations Research
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METIS-314909 ,EWI-25872 ,IR-98143 - Abstract
In de Wetenschapsvisie verraste het ministerie van OCW de Nederlandse wetenschappelijke wereld met haar voornemen NWO te ‘kantelen’. Dit voorstel leidde tot forse kritiek vanuit de wetenschap. Alle reden voor een interview met de voorzitter van het gebiedsbestuur Exacte Wetenschappen van NWO, wiskundige prof.dr. Arjen Doelman.
- Published
- 2015
31. Molecular analysis of the vaginal microbiome: an alternative for the diagnosis of bacterial vaginosis?
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Dols, J. A. M., Douwe Molenaar, Helm, J., Caspers, M. P. M., Kat-Angelino, A., Speksnijder, A. G. C. L., Westerhoff, H. V., Richardus, J. H., Boon, M. E., Reid, G., Vries, H. J. C., Remco Kort, Molecular Cell Physiology, Systems Bioinformatics, and AIMMS
- Published
- 2015
32. Draagvlak
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Boucherie, Richardus J. and Stochastic Operations Research
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METIS-315027 ,EWI-26451 ,IR-98392 - Published
- 2015
33. Appointments for care pathways the Geox/D/1 queue with slot reservations
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Zonderland, Maartje Elisabeth, Boucherie, Richardus J., Al Hanbali, Ahmad, Faculty of Behavioural, Management and Social Sciences, Stochastic Operations Research, Center for Healthcare Operations Improvement and Research, and Industrial Engineering & Business Information Systems
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Health Care ,IR-90539 ,EWI-24754 ,Probability generating functions ,MSC-90B22 ,urogenital system ,Care pathways ,METIS-303406 ,Matrix-geometric analysis ,Appointment planning ,MSC-60K25 - Abstract
Motivated by the increasing popularity of care pathways in outpatient clinics, where some patients complete a significant part of the path in one day, hospitals aim to optimize the flow of these patients by prioritizing them in the appointment planning process. This paper considers the Geo$^x /D/1$ queue with slot reservations that serves regular patients and priority patients. Priority patients reserve a time slot in a reservation window and are blocked when all slots in the reservation window are occupied by other priority patients. The reservation window models the advance reservation of service slots by patients on a care pathway. We model the Geo$^x /D/1$ queue as a $M/G/1$-type queue and apply a matrix-analytic approach, which simplifies to a matrix-geometric solution. We use the vector generating functions to derive the patients’ waiting times. Numerical experiments illustrate the influence of the reservation window on the number of regular and priority patients present and the blocking probabilities for priority patients.
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- 2015
34. Effective communication in outbreak management (ECOM). Development of an evidence-based tool for Europe
- Author
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Richardus, J., Korfage, I., French, J., Steenbergen, S.J.G. van, Das, E., Voeten, H., Reintjes, R., Richardus, J., Korfage, I., French, J., Steenbergen, S.J.G. van, Das, E., Voeten, H., and Reintjes, R.
- Abstract
Preconference organized at European Scientific Conference on Applied Infectious Disease Epidemiology (ESCAIDE), 10 november 2015, Item does not contain fulltext
- Published
- 2015
35. Introducing leprosy post-exposure prophylaxis into the health systems of India, Nepal and Indonesia: a case study.
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Tiwari, A., Mieras, L., Dhakal, K., Arif, M., Dandel, S., Richardus, J. H., and LPEP Study Group
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HANSEN'S disease patients ,PREVENTIVE medicine ,RIFAMPIN ,HANSEN'S disease treatment ,HANSEN'S disease diagnosis ,SOCIAL history ,DRUG therapy for Hansen's disease ,COMPARATIVE studies ,INTEGRATED health care delivery ,LEPROSTATIC agents ,HANSEN'S disease ,RESEARCH methodology ,MEDICAL cooperation ,RESEARCH ,PILOT projects ,GOVERNMENT programs ,EVALUATION research ,EVALUATION of human services programs ,PREVENTION - Abstract
Background: Leprosy has a wide range of clinical and socio-economic consequences. India, Indonesia and Nepal contribute significantly to the global leprosy burden. After integration, the health systems are pivotal in leprosy service delivery. The Leprosy Post Exposure Prophylaxis (LPEP) program is ongoing to investigate the feasibility of providing single dose rifampicin (SDR) as post-exposure prophylaxis (PEP) to the contacts of leprosy cases in various health systems. We aim to compare national leprosy control programs, and adapted LPEP strategies in India, Nepal and Indonesia. The purpose is to establish a baseline of the health system's situation and document the subsequent adjustment of LPEP, which will provide the context for interpreting the LPEP results in future.Methods: The study followed the multiple-case study design with single units of analysis. The data collection methods were direct observation, in-depth interviews and desk review. The study was divided into two phases, i.e. review of national leprosy programs and description of the LPEP program. The comparative analysis was performed using the WHO health system frameworks (2007).Results: In all countries leprosy services including contact tracing is integrated into the health systems. The LPEP program is fully integrated into the established national leprosy programs, with SDR and increased documentation, which need major additions to standard procedures. PEP administration was widely perceived as well manageable, but the additional LPEP data collection was reported to increase workload in the first year.Conclusions: The findings of our study led to the recommendation that field-based leprosy research programs should keep health systems in focus. The national leprosy programs are diverse in terms of organizational hierarchy, human resource quantity and capacity. We conclude that PEP can be integrated into different health systems without major structural and personal changes, but provisions are necessary for the additional monitoring requirements. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
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36. Public preferences for vaccination programmes during pandemics caused by pathogens transmitted through respiratory droplets - a discrete choice experiment in four European countries, 2013.
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Determann, D., Korfage, I. J., Fagerlin, A., Steyerberg, E. W., Bliemer, M. C., Voeten, H. A., Richardus, J. H., Lambooij, M. S., and de Bekker-GrobFagerlin, EW
- Published
- 2016
- Full Text
- View/download PDF
37. Improving Hand Hygiene Compliance in Nursing Homes: Protocol for a Cluster Randomized Controlled Trial (HANDSOME Study)
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Teesing, Gwen R, Erasmus, Vicki, Petrignani, Mariska, Koopmans, Marion P G, de Graaf, Miranda, Vos, Margreet C, Klaassen, Corné H W, Verduijn-Leenman, Annette, Schols, Jos M G A, Richardus, Jan Hendrik, and Voeten, Helene A C M
- Subjects
Medicine ,Computer applications to medicine. Medical informatics ,R858-859.7 - Abstract
BackgroundHand hygiene compliance is considered the most (cost-)effective measure for preventing health care–associated infections. While hand hygiene interventions have frequently been implemented and assessed in hospitals, there is limited knowledge about hand hygiene compliance in other health care settings and which interventions and implementation methods are effective. ObjectiveThis study aims to evaluate the effect of a multimodal intervention to increase hand hygiene compliance of nurses in nursing homes through a cluster randomized controlled trial (HANDSOME study). MethodsNursing homes were randomly allocated to 1 of 3 trial arms: receiving the intervention at a predetermined date, receiving the identical intervention after an infectious disease outbreak, or serving as a control arm. Hand hygiene was evaluated in nursing homes by direct observation at 4 timepoints. We documented compliance with the World Health Organization’s 5 moments of hand hygiene, specifically before touching a patient, before a clean/aseptic procedure, after body fluid exposure risk, after touching a patient, and after touching patient surroundings. The primary outcome is hand hygiene compliance of the nurses to the standards of the World Health Organization. The secondary outcome is infectious disease incidence among residents. Infectious disease incidence was documented by a staff member at each nursing home unit. Outcomes will be compared with the presence of norovirus, rhinovirus, and Escherichia coli on surfaces in the nursing homes, as measured using quantitative polymerase chain reaction. ResultsThe study was funded in September 2015. Data collection started in October 2016 and was completed in October 2017. Data analysis will be completed in 2020. ConclusionsHANDSOME studies the effectiveness of a hand hygiene intervention specifically for the nursing home environment. Nurses were taught the World Health Organization’s 5 moments of hand hygiene guidelines using the slogan “Room In, Room Out, Before Clean, After Dirty,” which was developed for nursing staff to better understand and remember the hygiene guidelines. HANDSOME should contribute to improved hand hygiene practice and a reduction in infectious disease rates and related mortality. Trial RegistrationNetherlands Trial Register (NTR6188) NL6049; https://www.trialregister.nl/trial/6049 International Registered Report Identifier (IRRID)DERR1-10.2196/17419
- Published
- 2020
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38. A quality assessment index framework for public health services: a Delphi study.
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Zhao, Z. G., Cheng, J. Q., Xu, S. L., Hou, W. L., and Richardus, J. H.
- Subjects
- *
EVALUATION of medical care , *PUBLIC health , *MEDICAL care , *DELPHI method , *MEDICAL personnel , *QUALITY assurance , *QUESTIONNAIRES , *RESEARCH funding , *STATISTICS , *QUALITATIVE research , *JUDGMENT sampling , *DATA analysis software , *DESCRIPTIVE statistics - Abstract
Objectives: This study sought consensus-based indices for quality assessment of the public health service (QAPHS) to evaluate the service quality of public health in Shenzhen and other cities in China. Study design: A qualitative study. Methods: A list of quality assessment indices was formed based on Donabedian theory. These indices were presented to an expert panel in a two-round Delphi study to establish a consensus view. A weight of indices was established to validate the applicability and practicability of the framework. The specialist authority coefficient and Kendall's W were also calculated based on statistical analysis. Results: A total of 30 experts participated in the Delphi study. Consensus was reached on four first-grade indices, nine second-grade indices and 28 third-grade indices. The specialist authority coefficient (Cr) was high (between 0.88 and 0.92), while Kendall's coefficient (W) of all the indices was > 0.5 with statistical significant differences (P < 0.05). This indicated correlation among panelists and had high reliability. Conclusions: A unified and hierarchical quality assessment index framework for public health services was established. The framework should be further tested and improved in practice. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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39. Association of environmental surface contamination with hand hygiene and infections in nursing homes: a prospective cohort study.
- Author
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Teesing GR, de Graaf M, Petrignani M, Erasmus V, Klaassen CHW, Schapendonk CME, Verduijn-Leenman A, Schols JMGA, Vos MC, Koopmans MPG, Richardus JH, and Voeten H
- Abstract
Background: Little is known about the presence of infections in nursing home residents, the causative micro-organisms, how hand hygiene (HH) influences the presence of infections in residents, and the extent to which environmental contamination is associated with the incidence of infection among residents., Aims: To establish if environmental contamination can be used as an indicator for HH compliance, and if environmental contamination is associated with the incidence of infection., Methods: Environmental surface samples (ESS) were collected in an exploratory study as part of a HH intervention in 60 nursing homes. ESS results from three distinct surfaces (nurses' station, communal toilet and residents' shared living area) were compared with nurses' HH compliance and the incidence of infection among residents. Real-time polymerase chain reaction assays were used to detect norovirus genogroup I and II, rhinovirus and Escherichia coli . HH compliance was measured by direct observation. The incidence of infection was registered weekly., Findings: Rhinovirus (nurses' station: 41%; toilet: 14%; living area: 29%), norovirus (nurses' station: 18%; toilet: 12%; living area: 16%) and E. coli (nurses' station: 14%; toilet: 58%; living area: 54%) were detected. No significant ( P <0.05) associations were found between HH compliance and the presence of micro-organisms. An association was found between E. coli contamination and the incidence of disease in general ( P =0.04). No other associations were found between micro-organisms and the incidence of disease., Conclusion: Rhinovirus, norovirus and E. coli were detected on surfaces in nursing homes. No convincing associations were found between environmental contamination and HH compliance or the incidence of disease. This study provides reference data about surface contamination., (© 2021 The Authors.)
- Published
- 2021
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40. Limited access to hepatitis B/C treatment among vulnerable risk populations: an expert survey in six European countries.
- Author
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Falla AM, Veldhuijzen IK, Ahmad AA, Levi M, and Hendrik Richardus J
- Subjects
- Alcoholism complications, Europe, Hepatitis B complications, Hepatitis C complications, Humans, Medically Uninsured statistics & numerical data, Refugees statistics & numerical data, Risk, State Medicine statistics & numerical data, Substance Abuse, Intravenous complications, Transients and Migrants statistics & numerical data, Health Services Accessibility statistics & numerical data, Hepatitis B therapy, Hepatitis C therapy, Vulnerable Populations statistics & numerical data
- Abstract
Background: To investigate access to treatment for chronic hepatitis B/C among six vulnerable patient/population groups at-risk of infection: undocumented migrants, asylum seekers, people without health insurance, people with state insurance, people who inject drugs (PWID) and people abusing alcohol., Methods: An online survey among experts in gastroenterology, hepatology and infectious diseases in 2012 in six EU countries: Germany, Hungary, Italy, the Netherlands, Spain and the UK. A four-point ordinal scale measured access to treatment (no, some, significant or complete restriction)., Results: From 235 recipients, 64 responses were received (27%). Differences in access between and within countries were reported for all groups except people with state insurance. Most professionals, other than in Spain and Hungary, reported no or few restrictions for PWID. Significant/complete treatment restriction was reported for all groups by the majority in Hungary and Spain, while Italian respondents reported no/few restrictions. Significant/complete restriction was reported for undocumented migrants and people without health insurance in the UK and Spain. Opinion about undocumented migrants in Germany and the Netherlands was divergent., Conclusions: Although effective chronic hepatitis B/C treatment exists, limited access among vulnerable patient populations was seen in all study countries. Discordance of opinion about restrictions within countries is seen, especially for groups for whom the health care system determines treatment access, such as undocumented migrants, asylum seekers and people without health insurance. This suggests low awareness, or lack, of entitlement guidance among clinicians. Expanding treatment access among risk groups will contribute to reducing chronic viral hepatitis-associated avoidable morbidity and mortality., (© The Author 2016. Published by Oxford University Press on behalf of the European Public Health Association.)
- Published
- 2017
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41. [Mortality due to chronic viral hepatitis B and C infections in the Netherlands].
- Author
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Hofman R, Nusselder WJ, Veldhuijzen IK, and Richardus JH
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- Cross-Sectional Studies, Hepatitis B, Chronic complications, Hepatitis C, Chronic complications, Humans, Netherlands epidemiology, Poisson Distribution, Regression Analysis, Hepatitis B, Chronic mortality, Hepatitis C, Chronic mortality
- Abstract
Objective: To estimate mortality due to chronic hepatitis B-virus (HBV) and hepatitis C-virus (HCV) infections in the Netherlands from 2002 to 2015., Design: A cross-sectional analysis based on cause-of-death statistics., Method: From Statistics Netherlands we obtained detailed data regarding the number of deaths per year in the following ICD-10 categories: chronic viral hepatitis; malignant neoplasm of the liver and intrahepatic bile ducts; fibrosis and cirrhosis of the liver; and alcoholic liver disease. We determined the population-attributable fractions (PAF) of HBV and HCV infections in mortality due to hepatocellular carcinoma (HCC) and cirrhosis of the liver, and added these to the recorded mortality from viral hepatitis in order to calculate total mortality. We used Dutch research as a basis for allocation to HCC, and a range of PAFs from 3 studies for cirrhosis. Poisson regression was used to assess mortality trends over time and any differences in demographic characteristics., Results: Around 500 Dutch people died annually of chronic viral hepatitis from 2002 to 2015, according to our 'middle' estimate; the 'lowest' estimate yields 340 and the 'highest' 600 people per year. The total mortality due to a chronic HBV and HCV infection did not change over time. The mortality for HCC due to viral hepatitis increased slightly over time and the mortality for cirrhosis decreased slightly. HCC mortality due to viral hepatitis was higher in Dutch people of non-western origin., Conclusion: Mortality from chronic viral hepatitis is mostly the result of cirrhosis of the liver and HCC. About 500 persons died annually from 2002 to 2015 from causes linked to viral hepatitis.
- Published
- 2016
42. Norovirus introduction routes into nursing homes and risk factors for spread: a systematic review and meta-analysis of observational studies.
- Author
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Petrignani M, van Beek J, Borsboom G, Richardus JH, and Koopmans M
- Subjects
- Caliciviridae Infections epidemiology, Caliciviridae Infections prevention & control, Disease Outbreaks prevention & control, Disease Transmission, Infectious, Humans, Infection Control methods, Observational Studies as Topic, Risk Factors, Caliciviridae Infections transmission, Norovirus isolation & purification, Nursing Homes
- Abstract
Norovirus causes substantial morbidity and mortality in nursing homes, with high attack rates in residents and staff. Immediate implementation of infection control measures is crucial. The aim of this review was to assess the evidence for sources and modes of introduction of norovirus, and factors contributing to spread. A systematic review of the literature was performed, including peer-reviewed original studies on outbreaks confirmed by reverse transcriptase-polymerase chain reaction. Data on source, index case, transmission mode, attack rate, outbreak duration, and risk factors were extracted. Attack rate and outbreak duration were compared by mode of introduction. Based on the selection criteria, 40 outbreak reports and 18 surveillance studies were included. There is little systematic information available on norovirus introduction into nursing homes, but, from evidence obtained from outbreak reports, it was determined that outbreaks often start with single index cases (57.5%), associated with higher attack rates among residents (P = 0.02). Foodborne introduction was described for 7% of outbreak reports that were characterized by finding multiple index cases. In surveillance studies only 0.7% of outbreaks was reported to be foodborne, 28.5% as person-to-person, and 70.8% remained unknown or not mentioned. Risk factor analyses suggested that transmission was associated with bedside care and exposure to vomit. These findings lead to the following recommendations: (i) to standardize outbreak reports; (ii) to improve early detection and isolation of sporadic cases; (iii) to improve personal hygiene of staff especially with highly dependent residents; and (iv) to comply with protocols to avoid exposure to vomit., (Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
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