Vergelijking van modellen om consumentenblootstelling te berekenen. Inventarisatie van mogelijke verbeteringen van ConsExpo

ConsExpo is een geschikt computerprogramma met rekenmodellen om de mate van blootstelling van mensen aan stoffen in consumentenproducten te schatten. Het programma kan verder verbeterd worden door bepaalde elementen uit andere bestaande rekenmodellen over te nemen. In ConsExpo wordt rekening gehouden met verschillende manieren van blootstelling: via de huid, via inhalatie en via orale opname. Bij het programma hoort een database, waarin standaardwaarden en blootstellingscenario's (wie wordt waar en hoe blootgesteld aan wat en hoe vaak) voor vele producttypen worden aangeboden (bijvoorbeeld cosmetica, verf, reinigingsmiddelen, ongediertebestrijdingsmiddelen en desinfectantia). De beschrijving van deze standaardwaarden en blootstellingscenario's wordt gerapporteerd in zogenoemde 'fact sheets'. Om ConsExpo verder te kunnen verbeteren is een vergelijking gemaakt met andere bestaande rekenmodellen. In de inventarisatie werd gekeken of deze modellen blootstellingscenario's, wiskundige methoden of andere aspecten bevatten die een nuttige aanvulling kunnen zijn voor ConsExpo. Uit de inventarisatie bleek dat ConsExpo zeer geschikt is om de blootstelling te schatten voor stoffen in consumentenproducten. In andere rekenmodellen werden namelijk geen blootstellingscenario's aangetroffen, die niet met ConsExpo berekend kunnen worden. Wel zijn er wiskundige methoden en andere elementen gevonden die voor ConsExpo van groot belang kunnen zijn. Zo kunnen sommige rekenmodellen blootstelling aan stoffen uit meerdere producten berekenen. De berekening van deze zogenaamde 'geaggregeerde blootstelling' zal mogelijk een rol gaan spelen in de risicoschatting van chemische stoffen onder de toekomstige wetgeving in de EU (REACH).ConsExpo is a suitable computer software programme with mathematical models for assessing the exposure of consumers to chemicals in consumer products. This tool can be further improved by adopting certain features from other existing consumer exposure modelling tools. In ConsExpo, different routes of exposure are taken into account, such as the route via the skin, and through inhalation and oral uptake. An important feature of ConsExpo 4.1 is that it contains a database with default values and standard exposure scenarios (who is exposed? where? how? and how often?) for a wide range of consumer product types. Examples include cosmetics, paint, cleaning products, pest control products and disinfectants. The default values and exposure scenarios are described in detail in fact sheets. ConsExpo was compared with other existing consumer modelling tools in an investigation to discover whether the tools contained any exposure scenarios, mathematical models or other features that might be useful for ConsExpo. The aim of the study was to find features that may improve this version (4.1). The investigation demonstrated that ConsExpo is very suitable for assessing exposure to chemicals in consumer products. The other tools did not contain any exposure scenarios for which assessment with ConsExpo is not possible. Nonetheless, a number of mathematical models and other software features have been found that may be of importance to ConsExpo. For example, some tools are capable of assessing exposure to a chemical in multiple products. Assessment of this so-called 'aggregate exposure' will possibly play an important role in the risk assessment of chemicals in future legislation in the EU (REACH).VW

ConsExpo - Consumenten blootstellings- en opnamemodellen - Programma handleiding

Dit rapport is een handleiding voor het gebruik van ConsExpo 4.0, de opvolger van ConsExpo 3.0, een computer programma dat is ontwikkeld ter ondersteuning van de blootstellingsschatting van stoffen in consumentenproducten. Er is een grote verscheidenheid aan consumentenproducten, consumenten en wijzen waarop deze consumenten producten gebruiken. Gemeten blootstellingsniveaus aan stoffen in producten zijn niet altijd voorhanden. Bij afwezigheid van deze gegevens kan ConsExpo 4.0 gebruikt worden om blootstellingen te schatten voor verschillende blootstellingsscenario's. Het programma biedt een aantal algemeen toepasbare blootstellingsmodellen en een database met gegevens over blootstellingsfactoren. Tezamen bieden modellen en database een uitgangspunt van waaruit blootstelling van een specifiek product geschat kan worden. Daarnaast kan ConsExpo 4.0 inzicht geven in de factoren die de blootstellingsniveaus van stoffen in consumentenproducten beinvloeden door gebruik te maken van de mogelijkheden van gevoeligheidsanalyse en probabilistische berekeningen. Bij de ontwikkeling van ConsExpo 4.0 is speciaal aandacht besteed aan het verbeteren van de transparantie en de gebruikersvriendelijkheid van de software. Dit rapport geeft een overzicht van ConsExpo 4.0, een uitleg van de beschikbare blootstellings- en opname modellen en belangrijke informatie met betrekking tot het interpreteren van de blootstellingsschatting.This report provides guidance to the use of ConsExpo 4.0, successor to ConsExpo 3.0, a computer program that was developed to assist in the exposure assessment of compounds in non-food consumer products. The wide range of available consumer products is associated with an even wider variation in consumers and product use. Measured data on exposure to compounds in products is not always available. In the absence of these data, ConsExpo 4.0 can be used to estimate the exposure for different exposure scenarios. The program offers a number of generally applicable exposure models and a database with data on exposure factors for a broad set of consumer products. Together, database and models provide the tools to assess exposure for a wide range of consumer products, whereby only basic additional information on product composition and the physicochemical properties of the compound of interest are needed. Moreover, ConsExpo 4.0 can be used to obtain insight in the factors affecting exposure levels to compounds in consumer product by using the tools of sensitivity analysis and probabilistic calculation. In the development of the fourth version of the program special effort has been taken to improve transparency and ease of use of the software. This report provides an overview of ConsExpo 4.0, an explanation of the available exposure and uptake models in ConsExpo 4.0 and important notes on the interpretation of the exposure assessment.VW

Equivalence of switching linear systems by bisimulation

A general notion of hybrid bisimulation is proposed for the class of switching linear systems. Connections between the notions of bisimulation-based equivalence, state-space equivalence, algebraic and input–output equivalence are investigated. An algebraic characterization of hybrid bisimulation and an algorithmic procedure converging in a finite number of steps to the maximal hybrid bisimulation are derived. Hybrid state space reduction is performed by hybrid bisimulation between the hybrid system and itself. By specializing the results obtained on bisimulation, also characterizations of simulation and abstraction are derived. Connections between observability, bisimulation-based reduction and simulation-based abstraction are studied.\ud \u

Quantum Measurement and the Aharonov-Bohm Effect with Superposed Magnetic Fluxes

We consider the magnetic flux in a quantum mechanical superposition of two values and find that the Aharonov-Bohm effect interference pattern contains information about the nature of the superposition, allowing information about the state of the flux to be extracted without disturbance. The information is obtained without transfer of energy or momentum and by accumulated nonlocal interactions of the vector potential $\vec{A}$ with many charged particles forming the interference pattern, rather than with a single particle. We suggest an experimental test using already experimentally realized superposed currents in a superconducting ring and discuss broader implications.Comment: 6 pages, 4 figures; Changes from version 3: corrected typo (not present in versions 1 and 2) in Eq. 8; Changes from version 2: shortened abstract; added refs and material in Section IV. The final publication is available at: http://link.springer.com/article/10.1007/s11128-013-0652-

Adequate use of asthma inhalation medication in children: more involvement of the parents seems useful

Background. Asthma and other chronic airway diseases can be effectively treated by inhaler therapy. Inhaler therapy depends on appropriate use of the inhaler. This study evaluates the knowledge among Dutch children and their parents regarding asthma inhaler therapy and appropriateness of its use. Findings. Five general practices selected all children aged 0 to 12 years on asthma inhalation medication. Children demonstrated inhaler use and were interviewed with their parents. 46 subjects were enrolled; mean age 5.5 years (SD 3.4) years; 26 (57%) were boys. Of the children using one inhaler only, 70% used the inhaler as indicated and of those using more than one inhaler 46%. On average 2.6 mistakes were made during demonstration of the technique, and 2 mistakes were reported in the interview. In total, 87% of the parents decided when and how the inhaler had to be used. Spacer cleaning was performed correctly by 49%; 26% reported a correct way of assessing how many doses were remaining. Conclusion. Dutch children make essential mistakes related to inhaler use that are easy to avoid. We recommend a better explanation and demonstration of the technique, and recommend involvement of the parents during instruction

Future X-ray timing missions

Thanks to the Rossi X-ray Timing Explorer (RXTE), it is now widely recognized that fast X-ray timing can be used to probe strong gravity fields around collapsed objects and constrain the equation of state of dense matter in neutron stars. We first discuss some of the outstanding issues which could be solved with an X-ray timing mission building on the great successes of RXTE and providing an order of magnitude better sensitivity. Then we briefly describe the 'Experiment for X-ray timing and Relativistic Astrophysics' (EXTRA) recently proposed to the European Space Agency as a follow-up to RXTE and the related US mission 'Relativistic Astrophysics Explorer' (RAE).Comment: To be published in `Proceedings of the Third Microquasar Workshop: Granada Workshop on galactic relativistic jet sources', Eds A. J. Castro-Tirado, J. Greiner and J. M. Paredes, Astrophysics and Space Science, in press. More about EXTRA can be found at: http://www.cesr.fr/~barret/extra.htm