268 research outputs found

    Resilience in interorganizational networks:Dealing with day-to-day disruptions in critical infrastructures

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    Purpose: Critical infrastructures (CIs) for essential services such as water supply and electricity delivery are notoriously vulnerable to disruptions. While extant literature offers important insights into the resilience of CIs following large-scale disasters, our understanding of CI resilience to the more typical disruptions that affect CIs on a day-to-day basis remains limited. The present study investigates how the interorganizational (supply) network that uses and manages the CI can mitigate the adverse consequences of day-to-day disruptions. Design/methodology/approach: Longitudinal archival data on 277 day-to-day disruptions within the Dutch national railway CI were collected and analyzed using generalized estimating equations. Findings: The empirical results largely support the study’s predictions that day-to-day disruptions have greater adverse effects if they co-occur or are relatively unprecedented. The findings further show that the involved interorganizational network can enhance CI resilience to these disruptions, in particular, by increasing the overall level of cross-boundary information exchange between organizations inside the network. Practical implications: This study helps managers to make well-informed choices regarding the target and intensity of their cross-boundary information-exchange efforts when dealing with day-to-day disruptions affecting their CI. The findings illustrate the importance of targeting cross-boundary information exchange at the complete interorganizational network responsible for the CI and to increase the intensity of such efforts when CI disruptions co-occur and/or are unprecedented. Originality/value: This study contributes to our academic understanding of how network-level processes (i.e. cross-boundary information exchange) can be managed to ensure interorganizational (supply) networks’ resilience to day-to-day disruptions in a CI context. Subsequent research may draw from the conceptual framework advanced in the present study for examining additional supply network-level processes that can influence the effectiveness of entire supply networks. As such, the present research may assist scholars to move beyond a simple dyadic context and toward examining complete supply networks

    Quantifying measures to limit wind driven resuspension of sediments for improvement of the ecological quality in some shallow Dutch lakes

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    Although phosphorus loadings are considered the main pressure for most shallow lakes, wind-driven resuspension can cause additional problems for these aquatic ecosystems. We quantified the potential effectiveness of measures to reduce the contribution of resuspended sediments, resulting from wind action, to the overall light attenuation for three comparable shallow peat lakes with poor ecological status in the Netherlands: Loosdrecht, Nieuwkoop, and Reeuwijk (1.8–2.7 m depth, 1.6–2.5 km fetch). These measures are: 1. wave reducing barriers, 2. water level fluctuations, 3. capping of the sediment with sand, and 4. combinations of above. Critical shear stress of the sediments for resuspension (Vcrit), size distribution, and optical properties of the suspended material were quantified in the field (June 2009) and laboratory. Water quality monitoring data (2002–2009) showed that light attenuation by organic suspended matter in all lakes is high. Spatial modeling of the impact of these measures showed that in Lake Loosdrecht limiting wave action can have significant effects (reductions from 6% exceedance to 2% exceedance of Vcrit), whereas in Lake Nieuwkoop and Lake Reeuwijk this is less effective. The depth distribution and shape of Lake Nieuwkoop and Lake Reeuwijk limit the role of wind-driven resuspension in the total suspended matter concentration. Although the lakes are similar in general appearance (origin, size, and depth range) measures suitable to improve their ecological status differ. This calls for care when defining the programme of measures to improve the ecological status of a specific lake based on experience from other lakes.

    A randomised trial of the effect and cost-effectiveness of early intensive multifactorial therapy on 5-year cardiovascular outcomes in individuals with screen-detected type 2 diabetes:The Anglo–Danish–Dutch Study of Intensive treatment in people with screen-detected diabetes in primary care (ADDITION-Europe) study

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    Background: Intensive treatment (IT) of cardiovascular risk factors can halve mortality among people with established type 2 diabetes but the effects of treatment earlier in the disease trajectory are uncertain.  Objective: To quantify the cost-effectiveness of intensive multifactorial treatment of screen-detected diabetes.  Design: Pragmatic, multicentre, cluster-randomised, parallel-group trial.  Setting: Three hundred and forty-three general practices in Denmark, the Netherlands, and Cambridge and Leicester, UK.  Participants: Individuals aged 40–69 years with screen-detected diabetes.  Interventions: Screening plus routine care (RC) according to national guidelines or IT comprising screening and promotion of target-driven intensive management (medication and promotion of healthy lifestyles) of hyperglycaemia, blood pressure and cholesterol.  Main outcome measures: The primary end point was a composite of first cardiovascular event (cardiovascular mortality/morbidity, revascularisation and non-traumatic amputation) during a mean [standard deviation (SD)] follow-up of 5.3 (1.6) years. Secondary end points were (1) all-cause mortality; (2) microvascular outcomes (kidney function, retinopathy and peripheral neuropathy); and (3) patient-reported outcomes (health status, well-being, quality of life, treatment satisfaction). Economic analyses estimated mean costs (UK 2009/10 prices) and quality-adjusted life-years from an NHS perspective. We extrapolated data to 30 years using the UK Prospective Diabetes Study outcomes model [version 1.3; © Isis Innovation Ltd 2010; see www.dtu.ox.ac.uk/outcomesmodel (accessed 27 January 2016)].  Results: We included 3055 (RC, n = 1377; IT, n = 1678) of the 3057 recruited patients [mean (SD) age 60.3 (6.9) years] in intention-to-treat analyses. Prescription of glucose-lowering, antihypertensive and lipid-lowering medication increased in both groups, more so in the IT group than in the RC group. There were clinically important improvements in cardiovascular risk factors in both study groups. Modest but statistically significant differences between groups in reduction in glycated haemoglobin (HbA1c) levels, blood pressure and cholesterol favoured the IT group. The incidence of first cardiovascular event [IT 7.2%, 13.5 per 1000 person-years; RC 8.5%, 15.9 per 1000 person-years; hazard ratio 0.83, 95% confidence interval (CI) 0.65 to 1.05] and all-cause mortality (IT 6.2%, 11.6 per 1000 person-years; RC 6.7%, 12.5 per 1000 person-years; hazard ratio 0.91, 95% CI 0.69 to 1.21) did not differ between groups. At 5 years, albuminuria was present in 22.7% and 24.4% of participants in the IT and RC groups, respectively [odds ratio (OR) 0.87, 95% CI 0.72 to 1.07), retinopathy in 10.2% and 12.1%, respectively (OR 0.84, 95% CI 0.64 to 1.10), and neuropathy in 4.9% and 5.9% (OR 0.95, 95% CI 0.68 to 1.34), respectively. The estimated glomerular filtration rate increased between baseline and follow-up in both groups (IT 4.31 ml/minute; RC 6.44 ml/minute). Health status, well-being, diabetes-specific quality of life and treatment satisfaction did not differ between the groups. The intervention cost £981 per patient and was not cost-effective at costs ≥ £631 per patient.  Conclusions: Compared with RC, IT was associated with modest increases in prescribed treatment, reduced levels of risk factors and non-significant reductions in cardiovascular events, microvascular complications and death over 5 years. IT did not adversely affect patient-reported outcomes. IT was not cost-effective but might be if delivered at a reduced cost. The lower than expected event rate, heterogeneity of intervention delivery between centres and improvements in general practice diabetes care limited the achievable differences in treatment between groups. Further follow-up to assess the legacy effects of early IT is warranted

    Design of the PROCON trial: a prospective, randomized multi – center study comparing cervical anterior discectomy without fusion, with fusion or with arthroplasty

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    BACKGROUND: PROCON was designed to assess the clinical outcome, development of adjacent disc disease and costs of cervical anterior discectomy without fusion, with fusion using a stand alone cage and implantation of a Bryan's disc prosthesis. Description of rationale and design of PROCON trial and discussion of its strengths and limitations. METHODS/DESIGN: Since proof justifying the use of implants or arthroplasty after cervical anterior discectomy is lacking, PROCON was designed. PROCON is a multicenter, randomized controlled trial comparing cervical anterior discectomy without fusion, with fusion with a stand alone cage or with implantation of a disc. The study population will be enrolled from patients with a single level cervical disc disease without myelopathic signs. Each treatment arm will need 90 patients. The patients will be followed for a minimum of five years, with visits scheduled at 6 weeks, 3 months, 12 months, and then yearly. At one year postoperatively, clinical outcome and self reported outcomes will be evaluated. At five years, the development of adjacent disc disease will be investigated. DISCUSSION: The results of this study will contribute to the discussion whether additional fusion or arthroplasty is needed and cost effective. TRIAL REGISTRATION: Current Controlled Trials ISRCTN4168184

    Diagnostic accuracy for different strategies of image-guided breast intervention in cases of nonpalpable breast lesions

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    To find out whether ultrasound-guided fine-needle aspiration (FNA) and ultrasound and stereotactic-guided large core needle biopsy (LCNB) are reliable alternatives to needle-localised open breast biopsy (NLBB) in daily practice, we performed a retrospective study and evaluated the validity of these methods. In all, 718 women with 749 nonpalpable breast lesions from three Dutch Hospitals were included, and the validity of the various methods for diagnosis was assessed. This was carried out according to a method described by Burbank and Parker for evaluating the quality of an image-guided breast intervention. We compared our results with the outcome of the COBRA study. Overall, all diagnostic strategies (NLBB, FNA, LCNB ultrasound and stereotactic guided) show comparable agreement rates. However, the miss rates differ: 2% for NLBB, 3% for COBRA (LCNB in study setting), 5% for FNA and 8-12% for LCNB in practice. Fine-needle aspiration was nonconclusive in 29%, and shows an overestimation for DCIS in 9%. The DCIS underestimate rate in NLBB was 8%. For the assessment of lesions consisting of microcalcifications only and to exclude malignancy in all other lesions, a 14-gauge needle should be used. Ultrasound-guided intervention can be performed in a large percentage of nonpalpable lesions. Lesions consisting only of microcalcifications on mammography need special attention
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