1,339 research outputs found
Comments on: "The role of the social environment in psychiatric research: Outstanding challenges and future directions by Dana March, James Kirkbride, Wim Veling"
No full textOn 17 March 2009, we hosted a live discussion of fresh new ideas in the epidemiology of schizophrenia. Discussion leaders Dana March of Columbia University, James Kirkbride of the University of Cambridge, and Wim Veling of Parnassia Psychiatric Institute delivered a wide-ranging discussion of social factors such as migration, ethnicity, and urbanicity, but also asked how this research could benefit from genetic insights. Finally, they discussed possible biological mechanisms that might transduce social factors into psychosi
TPS909615 Supplemental Material - Supplemental material for Ancestral calling, traditional health practitioner training and mental illness: An ethnographic study from rural KwaZulu-Natal, South Africa
No full textSupplemental material, TPS909615 Supplemental Material for Ancestral calling, traditional health practitioner training and mental illness: An ethnographic study from rural KwaZulu-Natal, South Africa by Martine van der Zeijst, Wim Veling, Elliot Mqansa Makhathini, Ezra Susser, Jonathan K. Burns, Hans W. Hoek and Ida Susser in Transcultural Psychiatry</p
sj-docx-1-tps-10.1177_13634615221105118 - Supplemental material for Discussing the unspoken: A qualitative analysis of online forum discussions on mental health problems in young Moroccan-Dutch migrants
No full textSupplemental material, sj-docx-1-tps-10.1177_13634615221105118 for Discussing the unspoken: A qualitative analysis of online forum discussions
on mental health problems in young Moroccan-Dutch migrants by Madelien H. van de Beek, Erwin Landman1, Wim Veling, Robert A. Schoevers, and Lian van der Krieke in Transcultural Psychiatry</p
Floating WIM Threshold Concept for Truck Weight Enforcement
Full text linkWeigh stations are the primary weight compliance checkpoints for commercial trucks. In the past several decades, states have used weigh-in-motion (WIM) technology to reduce delay and increase enforcement on overweight vehicles. This study offers a detailed analysis of weigh station systems and presents floating-threshold algorithms to improve the efficiency of WIM equipped weigh stations.
This research evaluates weigh station design and operational parameters using queueing theory and found that WIM technology not only enhances the effectiveness and efficiency of weigh station operations but also largely reduces travel delay for trucking companies. The effects of truck demand, truck weight distribution, static scale service time, WIM accuracy, and sorting threshold on weigh station operations have been analyzed. The author shows the importance of transponders in a WIM mainline weigh station operation. The author also proves that the increase of storage spaces within a weigh station may largely increase truck travel delay and does not significantly improve weigh station operations.
This research focuses on the development of floating-threshold algorithms. Since the number of trucks, particularly heavy trucks, has increased rapidly in recent decades, many weigh stations cannot meet the demand even when equipped with WIM systems. This problem is complicated by the fact that truck demands, truck weight distribution, and static scale service time vary by time of day and day of week. The author designed floating-threshold algorithms to automatically adapt to high truck demand and the varying of truck demand, truck weight distribution, and static scale service time, over time. When the queue at the weigh station is long, the threshold value is increased so as to avoid the closure of the weigh station while still catching the worst weight limit offenders. When the queue is short, the threshold value is lowered to increase the number of trucks inspected. Both the traditional fixed-threshold strategy and two floating-threshold strategies were modeled and tested using a microscopic simulation model. The results show that floating-threshold strategies are both more effective in weight enforcement and more efficient for heavy traffic flow and high-variance environments. The finding that different floating-threshold strategies have different effects indicates that it is necessary to make a further study on floating-threshold algorithms
The Impact of Tourism on Curacao's Economy: A Scenario Approach
No full textCuraçao is an autonomous countrywithin the Kingdom of the Netherlands. The governmentwants to support tourism development. However,various development strategies are possible. This articlepresents four scenarios of marketing and investmentstrategies that will affect the number of tourists fromThe Netherlands and North America (USA and Canada)in different ways. A multiplier model was used to calculatethe economic impacts of the four scenarios. Bydoing so, this article shows how the government’s decisionto support particular marketing and investmentstrategies may have certain outcomes for the number ofjobs in Curaçao’s tourism industry
Model Validation and New Water Control Strategies in Drinking Water Treatment Plant Wim Mensink
No full textStimela is an environment for standardized mathematical models of drinking water treatment processes. It can be used to predict the future water treatment situation which may happen or change. In water treatment plant Wim Mensink, the Stimela model train was set up to compare with other alternative water control strategies. Before starting the work of developing new water control strategies with Stimela model, Stimela model for Wim Mensink must be validated so that the model can be seen as a reliable and stable tool for the next work. Before the validation work, the current water control strategy for the treatment process needs to be investigated clearly to fulfil all the input control information is correct. Besides this, an experiment for obtaining the measured results of pellet diameters over different layers was performed in Wim Mensink. The validation work starts with single pellet softening process for three different reactors over first month from January 20th to February 20th. The fluidized bed height, pressure drop over total height of reactor, pellet diameters and porosities are validated. After that, the validation work is integrated with whole water treatment system to prove the function of pellet softening reactor and the four important water quality parameters over two important locations (after weir aerator location and final RO mixing location). The validated results of softening process are analysed by the relative error way to prove the reliability of the model results compared with measured results. The final step of the thesis work is developing the new water control strategies to optimize the current control plans of Wim Mensink. Five different water control strategies are put forward. They can be either reached separately according to their own advantages and limitations or fulfil with a step by step order as a whole optimization process. Moreover, the other water control strategies developed by engineering consultancy company DHV are evaluated here with Stimela model so that they can be proved reliable and achievable. In the future, the application of Stimela model will be spread over all the drinking water treatment plants in the Netherlands and contributes to the central automated control as a drinking water treatment operator training simulator.Sanitary EngineeringWatermanagementCivil Engineering and Geoscience
Use of Axle Load Spectra (ALS) for Estimating Calibration Drift in Weigh-In-Motion (WIM) Systems
Full text linkThis analysis's main objective is to determine WIM system errors based on axle loading without physically performing WIM equipment performance validation using test trucks. The presented methodology can be used to estimate systematic errors (calibration drift) in the WIM system at any point in time after the equipment calibration. This approach can help highway agencies select optimum timings for routine maintenance and calibration of WIM equipment without compromising its accuracy. The results show that the WIM accuracy for the single axle (SA) and tandem axle (TA) can be estimated with SA and TA NALS shape factors with an acceptable degree of error for bending plate (BP) and quartz piezo QP) sensors. The application and significance of the developed models were explained with the help of an example. The use of NALS to estimate the WIM system accuracy can save a significant amount of time and resources required for field validation of WIM performance every year.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Investigation of Truck Weights and Dimensions Using WIM Data
No full textAbstractThis paper presents a study carried out with extensive weigh-in-motion (WIM) data collected on the French main road network, involving 3 millions of trucks. The data were collected by three WIM stations located on highly trafficked highways and motorways, continuously over a whole year. The data were analyzed using statistical software developed by the US National Science Foundation.The trucks of the traffic flow were classified into almost 20 categories, depending on the silhouette, number and spacing of axles, body configuration (trailer/semi-trailer), type of axles (steering, driving or standard axle) and wheel or tire (single, twin, wide). The data were analyzed by category.The location of the centre of gravity of the payload was calculated and the variability of its abscissa along the vehicle was analyzed in each category. The loading patterns and behavior were analyzed and the results reported here for 5-axle articulated trucks and 2-axle rigid truck with 2-axle trailer.Then, the axle load distributions were analyzed by axle rank and truck category, and modeled with multimodal Gaussian probability distribution functions. The modes have been determined using a maximum of likelihood method. These modes are useful to design endurance tests of truck tires.These investigations provide a better knowledge about truck loading, overloads and truck aggressiveness on infrastructure, and may lead to optimization policies. In this case, the results are used directly in the domain of tyre optimization
Genetic mediation of the link between schizophrenia and cannabis use
No full textCannabis use is likely to increase the risk for schizophrenia, but it is neither a necessary nor a sufficient cause. Genetic factors may mediate the link between cannabis and schizophrenia. Research has recently started to explore interactions and correlations between genes, cannabis, and psychosis. Results from studies using indirect measures of genetic liability to psychotic disorder suggest that the psychotogenic effect of cannabis is greater in individuals with a predisposition for psychosis than in those without such a predisposition (gene-environment interaction) and that predisposition for psychosis is correlated with cannabis use (gene-environment correlation). The few studies that have investigated genetic polymorphisms directly found no evidence of correlation between cannabis use and genetic characteristics, and are inconclusive with regard to gene-environment interaction. One study reported an interaction effect between cannabis use and the Val158MET polymorphism of the catechol-O-methyltransferase (COMT) gene on the development of schizophrenia, another study did not replicate these findings, and yet another found this interaction only in individuals who already had a high predisposition for psychosis but not in those with no predisposition for psychosis. Thus, although it is likely that interactions between genes and cannabis influence the development of schizophrenia, further work is necessary to identify which genetic variations are involved and how these interact with cannabis. The inclusion of higher-order gene-gene and gene-environment interactions may be needed to understand the complex relationship between cannabis and schizophrenia. © 2008 Elsevier Ltd. All rights reserved
Age at migration and psychotic-like experiences: Clues in childhood to explain the increased risk for psychosis among ethnic minorities
No full textThe risk for psychotic disorders is increased among immigrants compared to native populations in several countries around the world. The exact nature of this environmental exposure remains unclear. In order to find an explanation for the excess risk, it is crucial to determine the relevant timing of exposure. Most research studied the period of onset of the disorder, but research should extend to early childhood and adolescence. Methods: Two studies were conducted. A 7-year first-contact incidence study identified and diagnosed all individuals aged 15-54with a first episode of psychosis in The Hague (N=618), and investigated the effect of age at the time of migration on the incidence of psychotic disorders among immigrants A comprehensive municipal registration system provided the denominator, including information on ethnicity and age at migration to the Netherlands. The second study assessed prevalence and correlates of psychotic-like experiences (PLEs) in a multi-ethnic cohort of 10-16 year-old schoolchildren (N=1563), using self-reportmeasures. Psychotic-like experiences were measured with 7 items from the Kiddie-Schedule for Affective Disorders and Schizophrenia. Additional questions explored frequency of the experiences, associated distress and cultural familiarity with the experiences. Emotional and behavioral problems were measured with the Strengths and Difficulties Questionnaire and the Social and Health Assessment. Results: Lower age at migration was associated with a higher incidence of psychotic disorders in immigrants. People who migrated between 0-4 years had the most elevated risk for psychotic disorders compared to Dutch (age- and sex-adjusted IRR= 2.96; 95% CI, 2.10-4.17) and the risk gradually decreased with older age at migration: adjusted IRR= 2.31 (1.61-3.29), 1.51 (1.02-2.25) to 1.00 (0.58-1.72) for age at migration categories 5-9, 10-14 and >29 respectively. Ethnic minority youth reported a higher rate of psychotic-like experiences with high impact (that is, high frequency or strong influence on their life) than Dutch youth (8.4% and 3.1% respectively, OR 2.8; 95% 1.7-4.6).Moroccan and Turkish youth more often knew a healthy person in their family or culture who had the same experiences, but after adjustment for this “cultural context”, differences with native Dutch youth in the impact of psychotic-like experiences remained substantial and statistically significant. Psychotic-like experiences were strongly correlated with emotional and behavioral problems. Conclusions: The adverse influence of migration on the risk of psychotic disorders is most prominent in early life. Psychotic-like experiences with high impact are more common in ethnic minority youth than in Dutch youth. These findings suggest that early childhood is the critical period for developing an increased vulnerability for psychotic disorders among immigrants, and that early, subclinical expression of this vulnerability can already be found in (pre-)adolescents from ethnic minority groups
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