Review of hydrologic and hydraulic studies and unsteady flow routing of the 1993 flood in the Upper Mississippi River system

"December 1997.""A division of the Illinois Department of Natural Resources.

Entrainment response of bed sediment to time-varying flows

Unsteady flows are ubiquitous in nature. In order to understand the behavior of sediment when subjected to unsteady flows, a set of experiments was performed in a rectangular duct with a mobile bed. A computer-operated vale governed the velocity of the water in the duct, and the flow velocity, wall shear stress, and vertical distribution of suspended sediment were simultaneously measured. Beds composed of 120 um and 580 um diameter sand were investigated. Both quasi-steady flows and pulse flows were investigated. Both quasi-steady flows and pulse flows were simulated in the duct. For the pulse flows the water was accelerated at a constant rate to a peak velocity and then decelerated at a constant rate to zero velocity. Phase lags were observed between the bed shear stress and the upward flux (entertainment) of sand from the bed. The phase lags were larger for tests with fine sand than for tests with coarse sand. Differences were attributed to differences in the bed roughness and flow Reynolds numbers. Relations based on flow acceleration and sediment size were developed for predicting the entertainment phase lag. Large phase lags can have a considerable impact on the amount of sediment transported by boat wakes, and other unsteady flows

Entrainment response of bed sediment to time-varying flows

Unsteady flows are ubiquitous in nature. In order to understand the behavior of sediment when subjected to unsteady flows, a set of experiments was performed in a rectangular duct with a mobile bed. A computer-operated vale governed the velocity of the water in the duct, and the flow velocity, wall shear stress, and vertical distribution of suspended sediment were simultaneously measured. Beds composed of 120 um and 580 um diameter sand were investigated. Both quasi-steady flows and pulse flows were investigated. Both quasi-steady flows and pulse flows were simulated in the duct. For the pulse flows the water was accelerated at a constant rate to a peak velocity and then decelerated at a constant rate to zero velocity. Phase lags were observed between the bed shear stress and the upward flux (entertainment) of sand from the bed. The phase lags were larger for tests with fine sand than for tests with coarse sand. Differences were attributed to differences in the bed roughness and flow Reynolds numbers. Relations based on flow acceleration and sediment size were developed for predicting the entertainment phase lag. Large phase lags can have a considerable impact on the amount of sediment transported by boat wakes, and other unsteady flows

Stormwater Best Management Practices Assessment for the City of Lincoln, Nebraska

The objective of this research was to assess BMP performance and implementation in Lincoln, Nebraska. In order to accomplish this objective, four tasks were established: sampling of stormwater runoff at eight sites located upstream of Holmes Lake, inspecting BMPs at construction sites in Lincoln, sampling and analysis of soil phosphorus levels in the Holmes Lake watershed, and conducting discussions with professionals involved with stormwater management in Lincoln. Based on the information collected during these tasks, several recommendations regarding the BMP assessment process are made including: recommendations for sampling site selection, an inexpensive flow monitoring method, and a rapid construction site BMP assessment protocol

HDAC3 Mediates the Inflammatory Response and LPS Tolerance in Human Monocytes and Macrophages

Histone deacetylases (HDACs) are a group of enzymes that control histone deacetylation and bear potential to direct expression of large gene sets. We determined the effect of HDAC inhibitors (HDACi) on human monocytes and macrophages, with respect to their polarization, activation, and their capabilities of inducing endotoxin tolerance. To address the role for HDACs in macrophage polarization, we treated monocytes with HDAC3i, HDAC6i or pan-HDACi prior to polarization into M1 or M2 macrophages using IFNγ or IL-4 respectively. To study the HDAC inhibition effect on cytokine expression, macrophages were treated with HDACi prior to LPS-stimulation. TNFα, IL-6, and p40 were measured with ELISA, whereas modifications of Histone 3 and STAT1 were assessed using western blot. To address the role for HDAC3 in repeated LPS challenge induction, HDAC3i or HDAC3 siRNA was added to monocytes prior to incubation with IFNγ, which were then repeatedly challenged with LPS and analyzed by means of protein analyses and transcriptional profiling. Pan-HDACi and HDAC3i reduced cytokine secretion in monocytes and M1 macrophages, whereas HDAC6i yielded no such effect. Notably, neither pan-HDACi nor HDAC3i reduced cytokine secretion in M2 macrophages. In contrast to previous reports in mouse macrophages, HDAC3i did not affect macrophage polarization in human cells. Likewise, HDAC3 was not required for IFNγ signaling or IFNβ secretion. Cytokine and gene expression analyses confirmed that IFNγ-treated macrophages consistently develop a cytokine response after LPS repeated challenge, but pretreatment with HDAC3i or HDAC3 siRNA reinstates a state of tolerance reflected by general suppression of tolerizable genes, possibly through decreasing TLRs expression, and particularly TLR4/CD14. The development of endotoxin tolerance in macrophages is important to reduce exacerbated immune response and limit tissue damage. We conclude that HDAC3 is an attractive protein target to mediate macrophage reactivity and tolerance induction in inflammatory macrophages

Structured feedback on students’ concept maps: the proverbial path to learning?

Good conceptual knowledge is an essential requirement for health professions students, in that they are required to apply concepts learned in the classroom to a variety of different contexts. However, the use of traditional methods of assessment limits the educator’s ability to correct students’ conceptual knowledge prior to altering the educational context. Concept mapping (CM) is an educational tool for evaluating conceptual knowledge, but little is known about its use in facilitating the development of richer knowledge frameworks. In addition, structured feedback has the potential to develop good conceptual knowledge. The purpose of this study was to use Kinchin’s criteria to assess the impact of structured feedback on the graphical complexity of CM’s by observing the development of richer knowledge frameworks. Fifty-eight physiotherapy students created CM’s targeting the integration of two knowledge domains within a case-based teaching paradigm. Each student received one round of structured feedback that addressed correction, reinforcement, forensic diagnosis, benchmarking, and longitudinal development on their CM’s prior to the final submission. The concept maps were categorized according to Kinchin’s criteria as either Spoke, Chain or Net representations, and then evaluated against defined traits of meaningful learning. The inter-rater reliability of categorizing CM’s was good. Pre-feedback CM’s were predominantly Chain structures (57%), with Net structures appearing least often. There was a significant reduction of the basic Spoke- structured CMs (P = 0.002) and a significant increase of Net-structured maps (P < 0.001) at the final evaluation (post-feedback). Changes in structural complexity of CMs appeared to be indicative of broader knowledge frameworks as assessed against the meaningful learning traits. Feedback on CM’s seemed to have contributed towards improving conceptual knowledge and correcting naive conceptions of related knowledge. Educators in medical education could therefore consider using CM’s to target individual student development

Multimodal surface-based morphometry reveals diffuse cortical atrophy in traumatic brain injury.

<p>Abstract</p> <p>Background</p> <p>Patients with traumatic brain injury (TBI) often present with significant cognitive deficits without corresponding evidence of cortical damage on neuroradiological examinations. One explanation for this puzzling observation is that the diffuse cortical abnormalities that characterize TBI are difficult to detect with standard imaging procedures. Here we investigated a patient with severe TBI-related cognitive impairments whose scan was interpreted as normal by a board-certified radiologist in order to determine if quantitative neuroimaging could detect cortical abnormalities not evident with standard neuroimaging procedures.</p> <p>Methods</p> <p>Cortical abnormalities were quantified using multimodal surfaced-based morphometry (MSBM) that statistically combined information from high-resolution structural MRI and diffusion tensor imaging (DTI). Normal values of cortical anatomy and cortical and pericortical DTI properties were quantified in a population of 43 healthy control subjects. Corresponding measures from the patient were obtained in two independent imaging sessions. These data were quantified using both the average values for each lobe and the measurements from each point on the cortical surface. The results were statistically analyzed as z-scores from the mean with a p < 0.05 criterion, corrected for multiple comparisons. False positive rates were verified by comparing the data from each control subject with the data from the remaining control population using identical statistical procedures.</p> <p>Results</p> <p>The TBI patient showed significant regional abnormalities in cortical thickness, gray matter diffusivity and pericortical white matter integrity that replicated across imaging sessions. Consistent with the patient's impaired performance on neuropsychological tests of executive function, cortical abnormalities were most pronounced in the frontal lobes.</p> <p>Conclusions</p> <p>MSBM is a promising tool for detecting subtle cortical abnormalities with high sensitivity and selectivity. MSBM may be particularly useful in evaluating cortical structure in TBI and other neurological conditions that produce diffuse abnormalities in both cortical structure and tissue properties.</p