p van der maas

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Estimation of nitrogen removal potential on WWTP Assen

Groene zeedijken in Noord-Duitsland en Denemarken: verslag van een studiereis 3-7 juni 1991

Bij zeer veel zeedijken in Sleeswijk-Holstein en op Jutland breken de golven tijdens de maatgeven... more Bij zeer veel zeedijken in Sleeswijk-Holstein en op Jutland breken de golven tijdens de maatgevende stormvloeden op grasmatten. Deze groene zeedijken blijken voldoende veilig te zijn. De aanleg wordt gekarakteriseerd door o.a. flauwe buitentaluds en een gedeeltelijke bezoding met zoute kwelderzoden. Bij een voldoende brede kwelder is een harde bekleding overbodig. In Nederland kunnen geheel of gedeeltelijk groene zeedijken onder vergelijkbare randvoorwaarden ook goed voldoen. Dat vraagt een hogere waardering van grasmatten en een andere aanleg en beheer. In het alsnog t.b.v. de advisering opgestelde reisverslag wordt ook ingegaan op de mogelijkheden en problemen in Nederland.

Targeted metagenomics reveals inferior resilience of farm soil resistome compared to soil microbiome after manure application

Science of The Total Environment, 2021

Soil bacteriome and resistome structures were influenced by different forces. • In time, manure b... more Soil bacteriome and resistome structures were influenced by different forces. • In time, manure bacteria decreased, but some native soil families were enriched. • Swift recovery of soil resistome diversity and abundance was observed over 21 days. • ResCap reliably correlated with standard methods for gene quantification (qPCR).

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Development of Online Sensors for the Detection and Quantification of the Microbial Regrowth Potential of Drinking Water

Water Contamination Emergencies, 2013

Microbial regrowth in drinking water distribution systems can lead to a deterioration of the aest... more Microbial regrowth in drinking water distribution systems can lead to a deterioration of the aesthetic water quality. In worst‐case circumstances, regrowth can allow the proliferation of pathogenic bacteria, resulting in a hygienic risk to the consumer.1 Some European countries, e.g. The Netherlands, has taken the approach of distributing high quality drinking water without the use of additional residual disinfectants such as chlorine. Drinking water treatment in such countries aims to limit microbial regrowth through limitation of the nutrients essential for growth. Under these conditions, the need to accurately monitor the general quality and microbial stability of drinking water has a high priority.

Cross-national agreement on disability weights: the European Disability Weights Project

Population health metrics, Jan 21, 2003

BACKGROUND: Disability weights represent the relative severity of disease stages to be incorporat... more BACKGROUND: Disability weights represent the relative severity of disease stages to be incorporated in summary measures of population health. The level of agreement on disability weights in Western European countries was investigated with different valuation methods. METHODS: Disability weights for fifteen disease stages were elicited empirically in panels of health care professionals or non-health care professionals with an academic background following a strictly standardised procedure. Three valuation methods were used: a visual analogue scale (VAS); the time trade-off technique (TTO); and the person trade-off technique (PTO). Agreement among England, France, the Netherlands, Spain, and Sweden on the three disability weight sets was analysed by means of an intraclass correlation coefficient (ICC) in the framework of generalisability theory. Agreement among the two types of panels was similarly assessed. RESULTS: A total of 232 participants were included. Similar rankings of disea...

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[Idiopathic scoliosis in adolescents; an inventory into the possibilities of studying the efficacy of screening and treatment]

Nederlands tijdschrift voor geneeskunde, Jan 29, 2002

To collect information for the purpose of establishing starting points and possibilities for a co... more To collect information for the purpose of establishing starting points and possibilities for a cost-effectiveness analysis of screening for adolescent idiopathic scoliosis (AIS). Interviews, literature review, questionnaires, an estimation of costs and discussions with experts and involved parties. Following an initial interview with 16 orthopaedic surgeons and school doctors a literature study into the efficacy of treatment was carried out regarding the years 1989-1999. The variation in current practice was delineated by means of a questionnaire sent to all 51 municipal health services in the Netherlands. The costs of screening and treatment were estimated on the basis of health insurance premiums and a municipal health service cost model. All of the results were presented to five methodological experts and finally the study results and the recommendations of the five methodological experts were evaluated during a meeting of persons especially invited for this purpose. Screening fo...

[The scientific basis for population screening for breast cancer in the Netherlands]

Nederlands tijdschrift voor geneeskunde, 2002

A recent Cochrane review stated that there was a lack of evidence for a decrease in mortality as ... more A recent Cochrane review stated that there was a lack of evidence for a decrease in mortality as a result of population breast-cancer screening. The principal data were drawn from five Swedish randomized controlled trials and one Canadian trial. However, the studies cannot be so easily combined because there were important differences in the attendance rate, detection rate, technical quality, referral rate, clinical baseline situation and screening interval. For example, in one of the studies the women from the control arm underwent an annual clinical palpation carried out by a trained nurse or physician, which could have led to an underestimation of the screening effect. Further breast-cancer mortality might not be a good outcome measure because this was not reliably determined; only total mortality was to be observed. This is clinically and methodologically incorrect because breast-cancer mortality was meticulously studied, documented and validated. In the Cochrane review it is su...

[Frequency of decisions to forgo (artificial) administration of food and fluids at life's end]

Nederlands tijdschrift voor geneeskunde, Jan 4, 1997

To determine the frequency and characteristics of decisions to forgo (artificial) feeding and hyd... more To determine the frequency and characteristics of decisions to forgo (artificial) feeding and hydration with hastening of death as a possible result. Retrospective, descriptive study. The Netherlands. Data were collected from questionnaires mailed to physicians attending 6060 deaths identified from death certificates dating from August through November 1995 (response rate: 77%). Decisions to forgo feeding and hydration preceded 8% of all deaths studied; for deaths attended by nursing home physicians this percentage was 23%, for deaths attended by general practitioners and specialists it was 4%. In 68% of all these death cases, the patients had been 80 years of age or over, and 76% of them had been partly or completely incompetent. The non-treatment decision had been discussed with relatives in 82% of all cases, and in 89% of the death cases attended by nursing home physicians. These patients had had (possibly) life-shortening medication less frequently than other patients for whom a...

[Asbestos and health: from patient presentation to recognition of occupational diseases in The Netherlands]

Nederlands tijdschrift voor geneeskunde, Jan 19, 1988

Reduction in breast cancer mortality due to the introduction of mass screening in the Netherlands: comparison with the United Kingdom

Journal of Medical Screening, 1999

Objective To assess the impact of the national breast cancer screening programme on breast cancer... more Objective To assess the impact of the national breast cancer screening programme on breast cancer mortality in the first years after its introduction. Setting The Netherlands and United Kingdom. Methods —MISCAN models, incorporating demographic, epidemiological, and screening characteristics of the region under study, were used to assess the mortality in the presence and absence of screening. Results Breast cancer mortality decreased in women aged 55–74 as the Dutch nationwide screening programme built up, and was 5% lower in 1996 than before the start of the programme. The mortality reduction due to screening in the age group 55–74 is expected to increase gradually to 18% in 1999, 10 years after the introduction of screening, and to 29% in the long term. In the United Kingdom screening was expected to achieve a mortality reduction of 5% and 18% in the age group 55–69 five and 10 years respectively after screening was started. A maximum mortality reduction of 24% in this age group i...

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Studying decision making in end of life care

PsycEXTRA Dataset

Refused and granted requests for euthanasia and assisted suicide in the Netherlands: interview study with structured questionnaire

BMJ, 2000

concentration, with the assumption that an inspired oxygen concentration of 24% equates to 2 l/mi... more concentration, with the assumption that an inspired oxygen concentration of 24% equates to 2 l/min; concentrations of 24%-35% with 2 l/min have been described. 5 The prescription of oxygen is complex, and a drug Kardex does not accommodate the precise details required for the variety of delivery devices. This was clearly shown in the second audit, where the accuracy of the prescription was greater with the chart than with the drug Kardex. We have shown that a specific prescription chart for oxygen improved clinical practice in our specialist medical respiratory centre, and we recommend the use of such a chart. Contributors: MED designed the study, analysed and interpreted the results, and wrote the paper. FK and AD analysed and interpreted the data. JCGS designed the study and the chart. AKW and CSH critically revised the paper. RMcLN designed the study and the chart and critically revised the paper. Competing interests: None declared.

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Stage distribution at first and repeat examinations in breast cancer screening

Journal of Medical Screening, 1999

Objectives To investigate observed stage distributions at first and repeat screenings. To compare... more Objectives To investigate observed stage distributions at first and repeat screenings. To compare the observed outcomes with expected values based on simulation modelling, varying the assumptions about the natural history of the disease. Methods An overview is made of observed data on stage distribution at first and repeat screenings and the difference between those distributions is summarised in a Gini coefficient. Four possible explanations for the observations are considered, two of these are worked out as Miscan simulation models, and the outcomes are compared with observations. Results Often the reported stage distributions at repeat screenings are not or only slightly more favourable than at first screenings and, in the ones that are more favourable, the difference is relatively small. If, in the Miscan model, it is assumed that there is no correlation between the duration of preclinical breast cancer in consecutive tumour size categories and that there is a strong influence o...

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End-of-life decisions in the United Kingdom

Palliative Medicine, 2009

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Evaluation of the Notification Procedure for Physician-Assisted Death in the Netherlands

New England Journal of Medicine, 1996

Background In 1991 a new procedure for reporting physician-assisted deaths was introduced in the ... more Background In 1991 a new procedure for reporting physician-assisted deaths was introduced in the Netherlands that led to a tripling in the number of reported cases. In 1995, as part of an evaluation of this procedure, a nationwide study of euthanasia and other medical practices concerning the end of life was begun that was identical to a study conducted in 1990. Methods We conducted two studies, the first involving interviews with 405 physicians (general practitioners, nursing home physicians, and clinical specialists) and the second involving questionnaires mailed to the physicians attending 6060 deaths that were identified from death certificates. The response rates were 89 percent and 77 percent, respectively. Results Among the deaths studied, 2.3 percent of those in the interview study and 2.4 percent of those in the death-certificate study were estimated to have resulted from euthanasia, and 0.4 percent and 0.2 percent, respectively, resulted from physician-assisted suicide. In 0.7 percent of cases, life was ended without the explicit, concurrent request of the patient. Pain and symptoms were alleviated with doses of opioids that may have shortened life in 14.7 to 19.1 percent of cases, and decisions to withhold or withdraw life-prolonging treatment were made in 20.2 percent. Euthanasia seems to have increased in incidence since 1990, and the ending of life without the patient's explicit request seems to have decreased slightly. For each type of medical decision except those in which life-prolonging treatment was withheld or withdrawn, cancer was the most frequently reported diagnosis. Conclusions Since the notification procedure was introduced, end-of-life decision making in the Netherlands has changed only slightly, in an anticipated direction. Close monitoring of such decisions is possible, and we found no signs of an unacceptable increase in the number of decisions or of less careful decision making.

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Life-terminating acts without explicit request of patient

The Lancet, 1993

In the Dutch nationwide study on medical decisions concerning the end of life (MDEL) life-termina... more In the Dutch nationwide study on medical decisions concerning the end of life (MDEL) life-terminating acts without the explicit request of the patient (LAWER) were noted in 0.8% of all deaths. We present here quantitative information and a discussion of the main issues raised by LAWER. In 59% of LAWER the physician had some information about the patient&#39;s wish; in 41% discussion on the decision would no longer have been possible. In LAWER patients tend to be younger and more likely to be male and to have cancer than in non-acute deaths generally. The physician (specialist or general practitioner) knew the patient on average 2.4 years and 7.2 years, respectively. Life was shortened by between some hours and a week at most in 86%. In 83% the decision has been discussed with relatives and in 70% with a colleague. In nearly all cases, according to the physician, the patient was suffering unbearably, there was no chance of improvement, and palliative possibilities were exhausted. MDEL probably will increase in number in future but interviews with Dutch physicians suggest a possible fall in LAWER, even though there will always be some situations in which a well-considered LAWER decision may have to be made.

End-of-life decision-making in six European countries: descriptive study

The Lancet, 2003

Background Empirical data about end-of-life decision-making practices are scarce. We aimed to inv... more Background Empirical data about end-of-life decision-making practices are scarce. We aimed to investigate frequency and characteristics of end-of-life decision-making practices in six European countries: Belgium, Denmark, Italy, the Netherlands, Sweden, and Switzerland. Methods In all participating countries, deaths reported to death registries were stratified for cause (apart from in Switzerland), and samples were drawn from every stratum. Reporting doctors received a mailed questionnaire about the medical decisionmaking that had preceded the death of the patient. The datacollection procedure precluded identification of any of the doctors or patients. All deaths arose between June, 2001, and February, 2002. We weighted data to correct for stratification and to make results representative for all deaths: results were presented as weighted percentages. Findings The questionnaire response rate was 75% for the Netherlands, 67% for Switzerland, 62% for Denmark, 61% for Sweden, 59% for Belgium, and 44% for Italy. Total number of deaths studied was 20 480. Death happened suddenly and unexpectedly in about a third of cases in all countries. The proportion of deaths that were preceded by any end-of-life decision ranged between 23% (Italy) and 51% (Switzerland). Administration of drugs with the explicit intention of hastening death varied between countries: about 1% or less in Denmark, Italy, Sweden, and Switzerland, 1•82% in Belgium, and 3•40% in the Netherlands. Large variations were recorded in the extent to which decisions were discussed with patients, relatives, and other caregivers. Interpretation Medical end-of-life decisions frequently precede dying in all participating countries. Patients and relatives are generally involved in decision-making in countries in which the frequency of making these decisions is high.

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Evaluation of the Digital Rectal Examination as a Screening Test for Prostate Cancer

JNCI Journal of the National Cancer Institute, 1999

Background: The utility of digital rectal examination (DRE) as a screening test for early detecti... more Background: The utility of digital rectal examination (DRE) as a screening test for early detection of prostate cancer has not been established. Therefore, we evaluated the usefulness of DRE as a stand-alone screening test and in conjunction with measured serum prostate-specific antigen (PSA) levels of 0-3.9 ng/mL and transrectal ultrasonography (TRUS). Methods: Our study population consisted of 10 523 men aged 54-76 years who were randomly assigned to the screening arm of the Rotterdam, The Netherlands, section of the European Randomized Study of Screening for Prostate Cancer. The underlying prevalence of detectable prostate cancer was estimated by logistic regression analysis and used for calculating the sensitivity of DRE as a test. Pathologic characteristics of 105 radical prostatectomy specimens were used to determine the aggressiveness of the tumors diagnosed (and missed) by DRE. Results: The overall detection rate for prostate cancer in this population when serum PSA measurement, DRE, and TRUS were used was 4.5%, and the detection rate with DRE alone was 2.5%. The positive predictive value of DRE ranged from 4% to 11% in men with PSA levels of 0-2.9 ng/mL and from 33% to 83% in men with PSA levels of 3.0-9.9 ng/mL or more. Most tumors detected by DRE in men with PSA levels of less than 4.0 ng/mL were small (mean volumes = 0.24-0.83 mL), and most were well differentiated (Gleason scores of 6 or less). Minimal, moderate, and advanced cancers were seen in 42%, 42%, and 16% of men, respectively, with a PSA level of 4.0 ng/ mL or less. DRE alone allowed detection of 264 (55.8%) of 473 cancers; 82 (17.3%) of the 473 cancers would have remained undetected by PSA-based screening alone (i.e., no follow-up procedures for PSA values of 0-3.9 ng/ mL). Conclusions: For PSA values of 0-3.9 ng/mL, the positive predictive value and sensitivity of DRE, tumor volume, and tumor grade were strongly dependent on PSA level. DRE has a poor performance in low PSA ranges.

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Euthanasia and other medical decisions concerning the end of life

Journal of Medical Ethics, 1994

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Healthcare costs of intellectual disability in the Netherlands: a cost-of-illness perspective

Journal of Intellectual Disability Research, 2002

Background Healthcare costs are continuously increasing, and impose a strong responsibility on go... more Background Healthcare costs are continuously increasing, and impose a strong responsibility on governments for an adequate allocation of resources among healthcare provisions and patients. Objectives The aims of the present study were to describe the healthcare costs of intellectual disability (ID) and other mental disorders in the context of the total costs of all other diseases, and to determinate the future need of healthcare resources, especially for ID and mental disorders. Methods The present authors performed a topdown cost-of-illness study comprising all healthcare costs of the Netherlands in . Data on healthcare use were obtained for all  healthcare sectors, and used to ascribe costs to disease groups, age and sex. Results Costs of mental disorders are by far the largest in the Dutch healthcare system. Some .% of total disease-specific costs could be ascribed to mental disorders: psychiatric conditions, .%; ID, .%; and dementia, .%. There are large differences between age and sex groups. The costs of ID and schizophrenia are higher among

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