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PubMed2004

Long-range transport and global fractionation of POPs: insights from multimedia modeling studies.

The long-range transport of persistent organic pollutants (POPs) is investigated with two multimedia box models of the global system. ChemRange is a purely evaluative, one-dimensional steady-state (level III) model; CliMoChem is a two-dimensional model with different temperatures, land/water ratios and vegetation types in different latitudinal zones. Model results are presented for three case studies: (i) the effect of atmospheric aerosol particles on the long-range transport of POPs, (ii) the effect of oceanic deposition on the long-range transport of different PCB congeners, (iii) the global fractionation of different PCB congeners. The model results for these case studies show: (i) the low atmospheric half-lives estimated for several organochlorine pesticides are likely to be inconsistent with the observed long-range transport of these compounds; (ii) export to the deep sea reduces the potential for long-range transport of highly hydrophobic compounds (but does not remove these chemicals from the biosphere); (iii) there are different meanings of the term global fractionation that refer to different aspects of the fractionation process and need to be distinguished. The case-study results further indicate that the influences of varying environmental conditions on the physicochemical properties and the degradation rate constants of POPs need to be determined.

Air Movements↗
PubMed2004

Prediction of overall persistence and long-range transport potential with multimedia fate models: robustness and sensitivity of results.

The hazard indicators persistence (P) and long-range transport potential (LRTP) are used in chemicals assessment to characterize chemicals with regard to the temporal and spatial extent of their environmental exposure. They are often calculated based on the results of multimedia fate models. The environmental and substance-specific input parameters of such models are subject to a range of methodological uncertainties and also influenced by natural variability. We employed probabilistic uncertainty analysis to quantify variance in P and LRTP predictions for chemicals with different partitioning and transport behavior. Variance found in the results is so large that it prevents a clear distinction between chemicals. Additionally, only small improvements are observed when evaluating the results relative to a benchmark chemical. This can be explained by the dominance of substance-specific parameters and the only small direct influence of environmental parameters on P and LRTP as model outcomes. The findings underline the importance of learning how environmental conditions cause variability in substance behavior for improved substance ranking and classification.

Air Movements↗
PubMed2005

A web-based multimedia spatial information system to document Aedes aegypti breeding sites and dengue fever risk along the US-Mexico border.

This paper describes a web-based multimedia spatial information system used to support a study of the re-invasion of Aedes aegypti, the mosquito vector for dengue fever, in the deserts of the southwest United States/northwest Mexico. The system was developed applying Open Geospatial Consortium and World Wide Web Consortium Open Specifications and using Open Source Software. The system creates a sensory-rich environment, one which allows users to interact with the system to explore connections among data (maps, remotely sensed images, text, graphs, 360 degree panoramas and photos), visualize information, formulate their own interpretations, generate hypotheses and reach their own conclusions.

Animals↗
PubMed2006

Dynamic modeling of chemical fate and transport in multimedia environments at watershed scale-I: theoretical considerations and model implementation.

A geo-referenced environmental fate model was developed for analyzing unsteady-state dispersion and distribution of chemicals in multimedia environmental systems. Chemical transport processes were formulated in seven environmental compartments of air, canopy, surface soil, root-zone soil, vadose-zone soil, surface water, and sediment. The model assumed that the compartments were completely mixed and chemical equilibrium was established instantaneously between the sub-compartments within each compartment. A fugacity approach was utilized to formulate the mechanisms of diffusion, advection, physical interfacial transport, and transformation reactions. The governing equations of chemical mass balances in the environmental compartments were solved simultaneously to reflect the interactions between the compartments. A geographic information system (GIS) database and geospatial analysis were integrated into the chemical transport simulation to provide spatially explicit estimations of model parameters at watershed scale. Temporal variations of the environmental properties and source emissions were also considered in the parameter estimations. The outputs of the model included time-dependent chemical concentrations in each compartment and its sub-compartments, and inter-media mass fluxes between adjacent compartments at daily time steps.

Computer Simulation↗
PubMed2006

Dynamic modeling of chemical fate and transport in multimedia environments at watershed scale-II: trichloroethylene test case.

A multimedia environmental fate model was developed to study the temporal dynamics and spatial distribution of a chemical pollutant at watershed scale. The theoretical considerations and implementation of the model were described in the accompanying paper (Part I). This paper presents the result of a test simulation on the transport of trichloroethylene (TCE) in the Connecticut River Basin. The simulation results were reported as time series of concentrations and inter-media transport fluxes in the compartments of atmosphere, plant, soil, surface water, and sediment. Predicted concentrations from the test simulation were compared with published field data or predictions by validated models. The temporal trends in TCE predictions were evaluated by comparing the simulation results with monthly TCE concentrations in various environmental compartments and monthly fluxes of inter-media transport processes. Results indicated that the simulation results were in reasonable agreement with reported data in the literature. The results also revealed that the mass transport of TCE from the atmosphere compartment to soil and surface water was a major route of TCE dispersion in the environment.

Ecosystem↗
PubMed2006

Impact of a multimedia intervention "Skinsafe" on patients' knowledge and protective behaviors.

BACKGROUND: Rates of malignant melanoma are rising, with those people with sun-sensitive skin most at risk. Health education interventions are needed to help people protect themselves by detecting early signs of melanoma and by protecting their skin from sunburn. This study aimed to evaluate the impact of an interactive multimedia intervention "Skinsafe" on patients' knowledge about melanoma and on their skin protective behaviors. METHODS: In this cluster-randomized, controlled trial conducted in Nottinghamshire, UK, doctors and nurses in 5 family practices prescribed Skinsafe to patients with higher risk skin characteristics. Measures of melanoma knowledge, perceived risk of melanoma and reported skin protective behaviors were obtained at baseline and at 6-month follow-up from 259 patients receiving the intervention and 330 patients with higher risk skin characteristics in 5 matched control practices. RESULTS AND DISCUSSION: Participants had low levels of melanoma knowledge at baseline. At follow-up, the intervention group had higher knowledge scores than control (3.71 vs. 3.03, P < or = 0.001), reported more protective skin behaviors (5.36 vs. 5.06, P = 0.007) and were more likely to report mole checking (odds ratio 1.67, 95% CI 1.04 to 2.70, P = 0.035). The Skinsafe intervention was evaluated positively by patients and could be used to support melanoma health education within clinical settings.

Adult↗
PubMed1998

Clinical case-based multimedia tutorials as a solution to some problems facing medical education.

Medical education faces many challenges as curricula become crowded and teacher numbers fall. In addition, there are moves to reduce factual overload and to concentrate more on pathophysiological principles illustrated by relevant clinical cases. We describe one means of addressing these problems, using computer-aided learning programs which are based on clinical cases, are interactive and which incorporate multimedia elements. These CD-ROM programs include student assessments, a resource of background material and support self-managed and distance learning.

CD-ROM↗
PubMed2003

Development and evaluation of an environmental multimedia fate model CHEMGL for the Great Lakes region.

This paper describes the development of a multimedia compartmental model--CHEMGL--which predicts the fate and transport of chemicals in the Great Lakes region and can be used for risk assessment. CHEMGL includes 10 compartments that describe a given region: air boundary layer, free troposphere, lower stratosphere, surface water, sediment, surface soil, vadose soil, groundwater zone, plant foliage and plant root. The model assumes that the compartments are completely mixed and chemical equilibrium between the phases within each compartment is assumed (e.g., suspended solids and biota in water). The attenuation mechanisms include advection, transformation reactions, and diffusive and nondiffusive intermedia transport between compartments. Input parameters include a description of each environmental media, emission rates, and chemical-specific properties and reaction rates. The numerical model results are in good agreement with the analytical solution for an example that examines the fate of benzene. Accordingly, the mathematical and computational components of the model were verified. CHEMGL predicted the concentration of four representative chemicals (atrazine, benzo[a]pyrene, benzene and hexachlorobenzene) in all five basins: Superior, Michigan, Huron, Erie and Ontario. The predicted concentrations fell within one to two orders of magnitude of data reported in the literature. These results suggest that the model is appropriate for estimating the fate and exposure of chemicals for a screening level risk assessment.

Fresh Water↗
PubMed1997

Applications of multimedia computers and video mixing to neuroethology.

Inexpensive multimedia computers offer new possibilities for mixing video and computer images, videotaping these mixed images, and extracting quantitative data from videotape. In this paper we describe methods for mixing images from a video camera and a Macintosh computer display using chroma keying, and we describe a simple circuit for analog video mixing and frame-counting. We present three applications of these video mixing methods to our neurophysiological and behavioral research with awake, behaving animals. These technologies enhance accuracy, speed, and flexibility during experiments, by allowing us to record an information-rich videotape of the subject and state of the experimental apparatus. After the experiment, these technologies facilitate selecting and extracting quantitative data from the videotape for further analysis. The videotape is especially useful in resolving minor inconsistencies or incomplete information in the notes and data files that often arise during analysis of complex experiments.

Animals↗
PubMed2000

CPR '98: a practical multimedia computer-based guide to cardiopulmonary resuscitation for medical students.

This paper describes an initiative to build a multimedia computer-based teaching package for cardiopulmonary resuscitation. The project resulted from a perceived gap in the undergraduate medical curriculum allied to concern from medical students. The software application was designed to be networked and used as an adjunct to taught life support courses for undergraduate medical students. The package comprises tutorials and test questions in basic and advanced life support. It incorporates sound, video, graphics and animation to illustrate the techniques involved and is distributed on CD ROM for the PC. The content is based on the 'Advanced Life Support Manual', produced by the Resuscitation Council (UK) and incorporates all changes to the guidelines made during 1997 and 1998. The basic life support section has been networked locally, and has been tested on more than 60 third year medical students attending a local basic life support course. It was found that students who used the package performed significantly better in theoretical assessments than those who did not.

Cardiopulmonary Resuscitation↗
PubMed1997

Interactive automatic fetal head measurements from ultrasound images using multimedia computer technology.

We have developed a tool to automatically detect inner and outer skull boundaries of a fetal head in ultrasound images. These boundaries are used to measure biparietal diameter (BPD) and head circumference (HC). The algorithm is based on active contour models and takes 32 s on a Sun SparcStation 20/71. A high-performance desktop multimedia system called MediaStation 5000 (MS5000) is used as a model for our future ultrasound subsystem. On the MS5000, the optimized implementation of this algorithm takes 248 ms. The difference (between the computer-measured values on MS5000 and the gold standard) for BPD and HC was 1.43% (sigma = 1.00%) and 1.96% (sigma = 1.96%), respectively. According to our data analysis, no significant differences exist in the BPD and HC measurements made on the MS5000 and those measurements made on the Sun SparcStation 20/71. Reduction in the overall execution time from 32 s to 248 ms will help making this algorithm a practical ultrasound tool for sonographers.

Algorithms↗
PubMed1998

Can a multimedia educational computer-based program on genital herpes teach patients about their disease?

Objective: Education of patients with genital herpes about their disease is time consuming. To evaluate the effectiveness of an educational computer program, we developed a multimedia interactive presentation to teach patients about genital herpes. Such programs can supplement clinician visits for patients with genital herpes, or those at risk for HSV acquisition.Methods: Patients seeking care for genital herpes, or those at risk for HSV acquisition, were asked to participate in the program during routine clinic visits at 5 physician's offices nationwide. A self-administered 7 item herpes knowledge questionnaire was given before and after participation. An additional questionnaire evaluating the satisfaction with the program was also self-administered at completion.Results: 428 patients were enrolled and completed the pre- and post-knowledge questionnaire and 332 patients completed the satisfaction survey. On the pre-test, 20.1% of patients answered all questions correctly, 65.4% answered correctly 4 to 6 questions, and 14.5% 3 or less. On the post-test, 32.9% of patients answered all questions correctly, 61.5% answered correctly 4 to 6 questions, and 5.6% 3 or less (P <.001 for pre- and post-test comparison). A positive change in knowledge between pre- and post-test was seen on 6 of 7 items (P <.001 for all 6). The overall satisfaction with the program was high: the mean rating was 6.2 on a scale 1 (poor) to 7 (excellent).Conclusion: Computer-based education programs about genital herpes may provide a useful adjunct to teaching in physician offices and result in knowledge gain about the disease, at least short-term. Such programs may assist in management of chronic sexually transmitted infections.

Journal Article↗
PubMed2001

Estimating the influence of forests on the overall fate of semivolatile organic compounds using a multimedia fate model.

On the basis of recently reported measurements of semivolatile organic compound (SOC) uptake in forest canopies, simple expressions are derived that allow the inclusion of a canopy compartment into existing non-steady-state multimedia fate models based on the fugacity approach. One such model is used to assess how the inclusion of the canopy compartment in the model affects the calculated overall behavior of SOCs with specific physical--chemical properties. The primary effect of the forest is an increase in the net atmospheric deposition to the terrestrial environment, reducing atmospheric concentrations and accordingly the extent of deposition to the agricultural and aquatic environments. This effect was most pronounced for chemicals with log KOA around 9-10 and log KAW -2 to -3; their average air concentrations during the growing season decreased by a factor of 5 when the canopy compartment was included. Concentration levels in virtually all compartments are decreased at the expense of increased concentrations in the forest soil. The effect of the forest lies not in a large capacity for these chemicals but in the efficiency of pumping the chemicals from the atmosphere to the forest soil, a storage reservoir with high capacity from which the chemicals can return to the atmosphere only with difficulty. Because of seasonal variability of canopy size and atmospheric stability, uptake into forests is higher during spring and summer than in winter. The model suggests that this may dampen temperature-driven seasonal fluctuations of air concentrations and in regions with large deciduous forests may lead to a temporary, yet notable dip in air concentrations during leaf development in spring. A sensitivity analysis revealed a strong effect of forest cover, forest composition, and degradation half-lives. A high degradation loss on the plant surface has the effect of preventing the saturation of the small plant reservoir and can cause very significant reductions in atmospheric concentrations of those SOCs for which uptake in the canopy is limited by the size of the reservoir.

Air Movements↗
PubMed2004

Cyclic exchanges and level of coupling between environmental media: intermedia feedback in multimedia fate models.

The importance of cyclic transport of chemicals between media in the environment can be expressed in terms of the Feedback correction factor--a multiplier that accounts for the fraction of an emission that returns to the medium of release after transfer to other media. This factor is calculated analytically by explicitly solving the appropriate system of mass balance equations or using matrix techniques. It generalizes the concept of stickiness, the ratio between the net and the overall deposition rate constants, to multipathway feedback, while providing a clearer view of the level of coupling between media and analyzing the importance of coupling. This paper first shows the usefulness of the total removal rate coefficient in each media (sum of degradation rate and all intermedia transfer rates) as a baseline to determine the chemical mass in different media, the characteristic travel distance and to understand the cyclic behavior, rather than starting from the degradation lifetimes or the overall persistence in the environment. Starting from this baseline, the importance of feedback is limited for most organic chemicals. The predicted media concentrations are influenced by less than 10% due to the cyclic nature of the intermedia transport for more than 90% of the 317 tested chemicals in a 4-compartment, steady-state, closed-system multimedia model. The Feedback correction factor is always less than a factor of 5 with the greatest values when transfer fractions are important in both directions for adjacent media. This corresponds to a restricted range in the K(AW) and K(OA) space with long chemical lifetimes in both adjacent media. This analysis of the importance of the Feedback correction factor, in conjunction with resultant criteria for when cyclic exchanges between media are likely to be significant, facilitates a more transparent understanding of how substance masses are distributed in the modeled system. It is one of the important criteria to determine to what extent media can be independently modeled.

Air↗
PubMed2001

Pollutant-specific scale of multimedia models and its implications for the potential dose.

The spatial range is a generic indicator for how far pollutants are likely to travel. It also indicates the appropriate, pollutant-specific area of a multimedia model, which is the square of the spatial range. Formulations of the spatial range can be based on advective or dispersive transport. They differ in whether they take the extent and shape of the earth's surface into account. We suggest the common element of the different approaches is that all account for the persistence and mobility of pollutants. The mobility is the expected travel speed and depends on the partitioning. This paper extends the concept of a pollutant-specific model scale through the introduction of a characteristic atmospheric scale height. It is the height of the atmosphere that would be needed to contain all the pollutant if the entire atmosphere had ground-level concentration, taking into account deposition and degradation. We define the spatial range as the expected advection-driven travel distance of a pollutant molecule released to a specific compartment. This novel analytical formulation is more comprehensive but encompasses all previous advection-based proposals of a spatial range. We evaluate the spatial range and scale height of 288 chemicals for releases to air, surface water, and surface soil. We find a strong correlation between the spatial range for air releases and the scale height because both depend on persistence. We investigate the effect of the spatial scale on calculations of the human toxicity potential, a screening-level risk indicator based on toxicity and potential dose. The product of model area and potential dose is found to be the same for calculations using a fixed model area and those using the pollutant-specific spatial scale. The introduction of the scale height, however, can change the potential dose by more than 1 order of magnitude.

Air Pollutants↗
PubMed1999

Sensitivity of concentration and risk predictions in the PRESTO and MMSOILS multimedia models: regression technique assessment.

This paper describes the application of two multimedia models, PRESTO and MMSOILS, to predict contaminant migration from a landfill that contains an organic chemical (methylene chloride) and a radionuclide (uranium-238). Exposure point concentrations and human health risks are predicted, and distributions of those predictions are generated using Monte Carlo techniques. Analysis of exposure point concentrations shows that predictions of uranium-238 in groundwater differ by more than one order of magnitude between models. These differences occur mainly because PRESTO simulates uranium-238 transport through the groundwater using a one-dimensional algorithm and vertically mixes the plume over an effective mixing depth, whereas MMSOILS uses a three-dimensional algorithm and simulates a plume that resides near the surface of the aquifer. A sensitivity analysis, using stepwise multiple linear regression, is performed to evaluate which of the random variables are most important in producing the predicted distributions of exposure point concentrations and health risks. The sensitivity analysis shows that the predicted distributions can be accurately reproduced using a small subset of the random variables. Simple regression techniques are applied, for comparison, to the same scenarios, and results are similar. The practical implication of this analysis is the ability to distinguish between important versus unimportant random variables in terms of their sensitivity to selected endpoints.

Algorithms↗
PubMed2002

A multimedia breast cancer education intervention for low-income Latinas.

This paper discusses the results from the field test of a multimedia health education intervention, designed to provide breast cancer education for low income Latinas. The purpose of the field test was to ascertain whether the intervention produced significant changes in breast cancer knowledge and attitude, and screening intentions. A total of 1,197 Latina women participated in the field study at six different sites. The majority of the participants were under 65 years of age, foreign-born with less than eight years of education and a weekly household income that fell in the lowest income quintile for 1998 (<$350.00). Participants were randomly assigned to a control or intervention condition. The control group was interviewed about their breast cancer knowledge, attitude and mammography intentions prior to exposure to the intervention, and served as the baseline group. Women in the intervention group exhibited higher knowledge scores than the pretest group (Chi sq., p < .0001). Never-screened women exhibited the largest differences in knowledge scores relative to the baseline sample. The intervention also increased the likelihood of women seeking information about a mammogram.

Adult↗
PubMed2002

A method to convert HDTV videos of broadcast satellite to RealSystem multimedia contents.

Recently, the Internet is widely used in the field of medicine. Daily use of e-mail for medical communication is very common. Also various information regarding hospitals can be accessed via the network. Apart from this practical use of the computer network, the mediums of telemedicine, tele-education, and telecare are also available. The Medical Information Network via Communications Satellite for University Hospital (MINCS-UH; http://www.umin.ac.jp/mincs/) was constructed by the Ministry of Education, Culture, Sports, Science and Technology. These programs feature high quality images viewed on High Definition Television (HDTV) through the Broadcast Satellite (BS). We have compiled a video library of MINCS-UH program contents with W-VHS tapes for HDTV and VHS or S-VHS tapesfor NTSC, available to medical staff in our university hospital through the Hospital local area network (Hospital intranet). We have also constructed a web-based streaming system that is a low cost, user-friendly multimedia delivery system capable of providing medical lectures. This system was constructed using the RealSystem package with the Internet Protocol (IP) network. Although the image quality of RealSystem is inferior to that of the original video, users can review lectures and medical congress presentations with video and audio through Hospital intranet, at any time that is convenient to them. This system can also be an efficient tool for distance learning and supports the diffusion of up-to-date information and technology to busy physicians via the Internet.

Education, Distance↗