321 research outputs found

    On Modeling Weak Sinks in MODPATH

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    Regional groundwater flow systems often contain both strong sinks and weak sinks. A strong sink extracts water from the entire aquifer depth, while a weak sink lets some water pass underneath or over the actual sink. The numerical groundwater flow model MODFLOW may allow a sink cell to act as a strong or weak sink, hence extracting all water that enters the cell or allowing some of that water to pass. A physical strong sink can be modeled by either a strong sink cell or a weak sink cell, with the latter generally occurring in low-resolution models. Likewise, a physical weak sink may also be represented by either type of sink cell. The representation of weak sinks in the particle tracing code MODPATH is more equivocal than in MODFLOW. With the appropriate parameterization of MODPATH, particle traces and their associated travel times to weak sink streams can be modeled with adequate accuracy, even in single layer models. Weak sink well cells, on the other hand, require special measures as proposed in the literature to generate correct particle traces and individual travel times and hence capture zones. We found that the transit time distributions for well water generally do not require special measures provided aquifer properties are locally homogeneous and the well draws water from the entire aquifer depth, an important observation for determining the response of a well to non-point contaminant inputs

    Virtual CMM using Monte Carlo methods based on frequency content of the error signal

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    In coordinate measurement metrology, assessment of the measurement uncertainty of a particular measurement is not a straight forward task. A feasible way for calculation of the measurement uncertainty seems to be the use of a Monte Carlo method. In recent years, a number of Monte Carlo methods have been developed for this purpose, we have developed a Monte Carlo method that can be used on CMM’s that takes into account, among other factors, the auto correlation of the error signal. We have separated the errors in linearity errors, rotational errors, straightness errors andsquareness errors. Special measurement tools have been developed and applied to measure the required parameters. The short-wave as well as the long-wave behavior of the errors of a specific machine have been calibrated. A machine model that takes these effects into account is presented here. The relevant errors of a Zeiss Prismo were measured, andthese data were used to calculate the measurement uncertainty of a measurement of a ring gauge. These calculations were compared to real measurements

    An international comparison of surface texture parameters quantification on polymer artefacts using optical instruments

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    An international comparison of optical instruments measuring polymer surfaces with arithmetic mean height values in the sub-micrometre range has been carried out. The comparison involved sixteen optical surface texture instruments (focus variation instruments, confocal microscopes and coherent scanning interferometers) from thirteen research laboratories worldwide. Results demonstrated that: (i) Agreement among different instruments could be achieved to a limited extent; (ii) standardised guidelines for uncertainty evaluation of areal surface parameters are needed for users; (iii) it is essential that the performance characteristics (and especially the spatial frequency response) of an instrument is understood prior to a measurement

    Dietary treatment in Dutch children with phenylketonuria:An inventory of associated social restrictions and eating problems

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    OBJECTIVES: Dietary treatment in phenylketonuria (PKU) is known to cause eating problems, but knowledge of both prevalence and magnitude, especially for social restrictions, is scarce. Our aim was to evaluate the social restrictions and eating problems that children with PKU and their caregivers experience with dietary treatment. METHODS: A web-based questionnaire, based on the Behavioral Pediatrics Feeding Assessment Scale with additional PKU-specific questions, was developed in close collaboration with and distributed by the Dutch PKU Association, which sent an e-mail to its members containing a link to the questionnaire. The questionnaire was completed by caregivers of children with PKU in the Netherlands and caregivers of age-matched children without PKU. Data were analyzed with the Kruskal-Wallis and Mann-Whitney U test using SPSS. RESULTS: Compared with caregivers of children in the control group (ages 1-16 y; n = 50), caregivers of children with PKU (ages 1-16 y; n = 57) reported more difficulty in offering food variety, experienced more stress when eating an evening meal outside the home and during vacation, and were stricter about (accidental) spilling of food during dinner by the child (P < 0.05). They also reported to being angrier, more frustrated, and more anxious when feeding their child, and they more often felt that their child's eating pattern had a negative influence on the child's general health (P < 0.05). CONCLUSION: This pilot study provides further evidence that restriction of social activities and eating problems associated with dietary restrictions is more common in children with PKU, and warrants awareness on this topic among professionals working with these children

    Early-branching gut fungi possess a large, comprehensive array of biomass-degrading enzymes

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    available in PMC 2016 November 07The fungal kingdom is the source of almost all industrial enzymes in use for lignocellulose bioprocessing. We developed a systems-level approach that integrates transcriptomic sequencing, proteomics, phenotype, and biochemical studies of relatively unexplored basal fungi. Anaerobic gut fungi isolated from herbivores produce a large array of biomass-degrading enzymes that synergistically degrade crude, untreated plant biomass and are competitive with optimized commercial preparations from Aspergillus and Trichoderma. Compared to these model platforms, gut fungal enzymes are unbiased in substrate preference due to a wealth of xylan-degrading enzymes. These enzymes are universally catabolite-repressed and are further regulated by a rich landscape of noncoding regulatory RNAs. Additionally, we identified several promising sequence-divergent enzyme candidates for lignocellulosic bioprocessing.United States. Dept. of Energy. Office of Science (Biological and Environmental Research (BER) program)United States. Department of Energy (DOE Grant DE-SC0010352)United States. Department of Agriculture (Award 2011-67017-20459)Institute for Collaborative Biotechnologies (grant W911NF-09-0001

    Central Multifocal Choroiditis: Platelet Granularity as a Potential Marker for Treatment With Steroid-Sparing Immunomodulatory Therapy

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    Purpose: We aimed to evaluate the blood cell composition in patients with central multifocal choroiditis (cMFC), a rare form of posterior uveitis predominantly affecting young myopic women. Methods: In this retrospective observational case-control study, a 104-parameter automated hematocytometry was conducted by the Cell-Dyn Sapphire hematology analyzer for 122 cases and 364 age- and sex-matched controls. Cox proportional regression analysis was used to assess the relation between the blood cell composition and the time between disease onset (first visit) and the start of systemic corticosteroid-sparing immunomodulatory therapy (IMT). Results: At a false discovery rate of 5% (Padj), we identified a decrease of blood monocytes in cases with cMFC, which could be attributed to disease activity. Cox proportional hazard analysis including age and sex revealed that increased platelet granularity (measured by mean intermediate angle scatter) was an independent risk factor for treatment with IMT (hazard ratio = 2.3 [95% confidence interval = 1.28 - 4.14], Padj = 0.049). The time between the first presentation and the start of IMT was 0.3 years in the group with an increased platelet granularity and 3.4 years in the group without increased platelet granularity. Conclusions: Patients with cMFC demonstrated a decrease in blood monocytes. Moreover, platelet granularity could potentially be used as a marker for treatment with IMT

    Health-related quality of life after prophylactic cranial irradiation for stage III non-small cell lung cancer patients:Results from the NVALT-11/DLCRG-02 phase III study

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    BACKGROUND AND PURPOSE: The NVALT-11/DLCRG-02 phase III trial (clinicaltrials.gov identifier: NCT01282437) showed that, after standard curative intent treatment, prophylactic cranial irradiation (PCI) decreased the incidence of symptomatic brain metastases (BM) in stage III non-small cell lung cancer (NSCLC) patients compared to observation. In this study we assessed the impact of PCI on health-related quality of life (HRQoL). In addition, an exploratory analysis was performed to assess the impact of neurocognitive symptoms and symptomatic BM on HRQoL. MATERIALS AND METHODS: Stage III NSCLC patients were randomized between PCI and observation. HRQoL was measured using the EuroQol 5D (EQ-5D-3L), EORTC QLQ-C30 and QLQ-BN20 instruments at completion of standard curative intent treatment and 4 weeks, 3, 6, 12, 24 and 36 months thereafter. Generalized linear mixed effects (GLM) models were used to assess the impact of PCI compared to observation over time on three HRQoL metrics: the EORTC QLQ-C30 global health status and the EQ-5D-3L utility and visual analogue scale (EQ VAS) scores. RESULTS: In total, 86 and 88 patients were included in the PCI and observation arm, with a median follow-up of 48.5 months (95% CI 39-54 months). Baseline mean HRQoL scores were comparable between the PCI and observation arm for the three HRQoL metrics. In the GLM models, none of the HRQoL metrics were clinically relevant or statistically significantly different between the PCI and the observation arm (p-values ranged between 0.641 and 0.914). CONCLUSION: No statistically significant nor a clinically relevant impact of PCI on HRQoL was observed
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