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The concept of dual flowing continuum is a promising approach for modeling solute transport in porous media that includes biofilm phases. The highly dispersed transit time distributions often generated by these media are taken into consideration by simply stipulating that advection-dispersion transport occurs through both the porous and the biofilm phases. Both phases are coupled but assigned with contrasting hydrodynamic properties. However, the dual flowing continuum suffers from intrinsic equifinality in the sense that the outlet solute concentration can be the result of several parameter sets of the two flowing phases. To assess the applicability of the dual flowing continuum, we investigate how the model behaves with respect to its parameters. For the purpose of this study, a Global Sensitivity Analysis (GSA) and a Statistical Calibration (SC) of model parameters are performed for two transport scenarios that differ by the strength of interaction between the flowing phases. The GSA is shown to be a valuable tool to understand how the complex system behaves. The results indicate that the rate of mass transfer between the two phases is a key parameter of the model behavior and influences the identifiability of the other parameters. For weak mass exchanges, the output concentration is mainly controlled by the velocity in the porous medium and by the porosity of both flowing phases. In the case of large mass exchanges, the kinetics of this exchange also controls the output concentration. The SC results show that transport with large mass exchange between the flowing phases is more likely affected by equifinality than transport with weak exchange. The SC also indicates that weakly sensitive parameters, such as the dispersion in each phase, can be accurately identified. Removing them from calibration procedures is not recommended because it might result in biased estimations of the highly sensitive parameters.

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BACKGROUND: Cytomegalovirus (CMV) is the most frequent cause of congenital infection. The aim of this research was to describe the decision-process for parents to pursue gestation or to ask medical abortion after materno-fetal CMV infection. OBJECTIVES: The primary objective of this study is to analyze the decision-process for parents after materno-fetal infection with positive PCR after amniocentesis, to ask or not a medical termination of pregnancy (TOP). The secondary objectives are to compare ours results with literature review (pronostics factors, ultrasonographic signs and neonatal symptomatology). MATERIALS AND METHODS: This is a retrospective study, focused with a pluridisciplinary materno-fetal prenatal medical center, during a 14-year long period. Only 15 patients have been included in the study. They have been divided in 2 groups (the first group who decided to ask a TOP [n=8] and the second group who pursued the gestation [n=7]). We compare respectively their clinical, ultrasonographic, or other imagery and biological paths, before and after the birth. RESULTS: A total of 15/16 patients had a CMV seroconversion before 20weeks of gestation. The only infection after 20SA did not have any sequelae. The ultrasonography and the cerebral fetal MRI appeared to be very complementary for the assesment of brain injury, which is more frequent in the group with a TOP (7/8 versus 4/7). Three neonates out of 4 who had a cord positive viral blood load at birth are presenting neonatal symptoms, 2 of them will have severe brain and hearing injuries, the fourth one had no sequelae after 6months of life. CONCLUSION: Only the presence of ultrasonographic major brain damages, and confirmation with MRI, had a pejorative value as prognosis factor suggesting to patients to choose a TOP. Nevertheless, other ways of research are possible to assess the prognostic value in this difficult prenatal diagnosis process.

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An out-diffusion laboratory experiment using a non-reactive tracer was fitted using the Time Domain Diffusion (TDD) method. This rapid particle tracking method allows simulation of the heterogeneous diffusion based on pore-scale images and local values of diffusivities. The superimposed porosity and mineral 2D maps act as computation grids to condition diffusion pathways. We focused on a Palmottu granite sample, in which the connected pore space has a composite microstructure with cracks linking microporous minerals and is above the percolation threshold. Three main results were achieved: (i) When compared to the fitting obtained with one coefficient (best mean square residual R = 1.6 x 10(-2)), diffusion is shown to be suitably characterised with two coefficients related to cracks and microporous minerals (best R = 6.5 x 10(-4)), (ii) rather than imposing a local apparent diffusion coefficient D(a) independent of the local porosity Phi, a best fit is obtained by applying Archie's relationship D(a) = D(0) x G with G = Phi(m) to each pixel of the calculation grids (G is the geometry factor, D(0) is the diffusion coefficient in free fluid, and m is Archie's exponent), and (iii) the order of magnitude of the fitted diffusion coefficient or Archie's exponents (m=0 for microcracks and m=1.82 for microporous minerals) is physically realistic.

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The aim of this work was to experimentally evaluate the role of ionic strength and pore velocity on clay suspension transport and retention through a saturated porous medium. A smectite suspension was injected into columns filled with a very fine quartz sand. Experiments were carried out at constant pore velocity with increasing ionic strength adjusted with a divalent electrolyte (CaCl2) and at constant ionic strength (using three chemical conditions) with decreasing pore velocity. Typical colloid breakthrough curves show two important behaviors: a constant outlet concentration value after a transient phase, and a pronounced tailing effect at the end of the injection step. No differences were observed between the mean travel time of a solute tracer and that of the clay suspension. The classical advection-dispersion equation coupled with a first-order two-site kinetics model was used to reproduce the experimental breakthrough curves. The kinetic model consisted in a site with irreversible deposition and a reversible site used to reproduce the transient phase preceding the plateau of the experimental breakthrough curves. The particle fraction kept by the porous medium increases with ionic strength; consequently the kinetic parameters of the numerical model vary with chemistry. The irreversible sorption rate (Kirr: equivalent to a clean-bed filter coefficient) increases with ionic strength and was directly determined from experimental data. With increasing ionic strength, the deposition rate (Kd) for the reversible sorption increases whereas the release rate (Kr) decreases. The kinetic parameters of the reversible site show an evolution with pore velocity similar to that observed in kinetics model used for modeling solute transport in double porosity media. With decreasing pore velocities, the retention of clay particles increases but the kinetic deposition coefficient of the irreversible site decreases. Particle deposition can also be described and reinterpreted in terms of collector efficiency using the concept of the sphere-in-cell model. The collector efficiency, which adds a correction to the kinetic parameter with the residence time, is a more consistent way to represent particle retention. Its value increases with increasing ionic strength and decreasing pore velocity.

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Studies on the inter-rater reliability on the Children's Global Assessment Scale (CGAS) and the Global Assessment of Psychosocial Disability (GAPD) involving different subgroups of 145 outpatients from 4 to 16 years of age showed fair to substantial intraclass correlations of 0.59 to 0.90. Raters of different training levels participated. Interrater reliability was dependent on number of ratings per rater, training, available data sources and experience. A more detailed description of anchor points resulted in higher inter-rater agreement by psychiatrists training in child and adolescent psychiatry, but did not influence the inter-rater reliability among more (widely) experienced raters. Both the CGAS and the GAPD seem to be sufficiently reliable tools in clinical practice. The CGAS seems to be more sensitive to inter-rater variation than the GAPD.

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