Aquatic Oligochaeta of Mud Lake, and its inlet and outlet stream

Aquatic invertebrates of Wisconsin have been studied extensively, but until recently, little work has been done with aquatic oligochaetes (segmented worms). Much of the previous work was primarily concerned with the tubificid fauna of the Great Lakes (Hiltunen 1961; Howmiller 1972; Howmiller and Beeton 1910; Spencer 1980). Also, Howmiller (1914) described the aquatic Oligochaeta found in the inland waters of Wisconsin, and Howmiller and Loden (1916) provided additional information which contains the most current list of species found in Wisconsin. A study was carried out during May and June 1980 at the University of Wisconsin - Milwaukee Field Station to determine composition and density of aquatic oligochaetes present in a bog lake (Mud Lake) and its inlet and outlet streams

Impact of Black Shale Weathering on Sediment Quality

Weathering of black shales leads to elevated metal concentrations in both surface water and stream sediments. In spite of the recent focus on black shales, few data exist on the ecological impacts of this process particularly on aquatic organisms. The key objective of this study was to determine the impact of trace metal concentrations in sediments upon aquatic organisms. To achieve the above objective, stream sediment samples were collected from streams draining black shale and limestone (used as a reference stream) lithologies located in central Arkansas between June 2003 and January 2004. Trace metal concentrations were measured by the dynamic reaction cell inductively coupled plasma mass spectrometry (ICPMS; Perkin Elmer DRC II) following EPA 6020 methodology. Sediment samples were tested for toxicity using standard EPA protocols. The trace metal concentrations in sediments and acute toxicity test findings using midge larvae, Chironomus tentans with endpoints measured as growth and survival is presented. Our results showed that there are significant differences in survival of the midge larvae among the study sites and also among the different sampling occasions. Percent survival of the midge larvae in the sediments derived from black shales was lower than that observed in the limestone-derived stream sediments. Significant differences in growth of the midge larvae were also observed among the sites with the control and reference stream sediments having higher growth than the black shale stream sediments. Though our measured metal concentrations in the black shale-derived sediments were below the Effects Range-Low, there is a great potential of metal accumulation in the fine sediment fraction particularly during baseflow regimes. At the time, metals can be concentrated in the fine sediment fraction due to the low discharge and less dilution. The study thus far has shown that the black shale metal-enriched stream sediments have both lethal and sublethal effects on aquatic organisms and higher organisms through food chain transfer

Grid Size Effects With Smeared Cracking in Finite Element Analysis of Reinforced Concrete

The effects of modeling parameters on the response of finite element representations of reinforced concrete members are examined. Convergence of load-deflection curves and cracking patterns is studied. Nonlinear behavior is limited to cracking of the concrete and yielding of the reinforcement. The ''smeared" crack representation is governed by a limiting tensile stress criterion. Concrete is treated as linear elastic in compression. Reinforcement has a bilinear stress-strain curve. Constant strain bar elements and rectangular isoparametric elements model the steel and the concrete, respectively. Analyses are performed for flexural members with span-to-depth ratios of 12-1, 5-l and 2-1, under both a uniformly distributed load and a concentrated load at midspan, using a minimum of three variations in grid refinement. Load-deflection curves exhibit convergence with grid refinement. Concrete tensile s tr eng th has a negligible influence on response for the members studied. Load increment size affects the response only in unstable regions of the load deflection curve and does not affect the stiff ness or the post-yield response

A novel research definition of bladder health in women and girls: Implications for research and public health promotion

BACKGROUND:Bladder health in women and girls is poorly understood, in part, due to absence of a definition for clinical or research purposes. This article describes the process used by a National Institutes of Health funded transdisciplinary research team (The Prevention of Lower Urinary Tract Symptoms [PLUS] Consortium) to develop a definition of bladder health. METHODS:The PLUS Consortium identified currently accepted lower urinary tract symptoms (LUTS) and outlined elements of storage and emptying functions of the bladder. Consistent with the World Health Organization's definition of health, PLUS concluded that absence of LUTS was insufficient and emphasizes the bladder's ability to adapt to short-term physical, psychosocial, and environmental challenges for the final definition. Definitions for subjective experiences and objective measures of bladder dysfunction and health were drafted. An additional bioregulatory function to protect against infection, neoplasia, chemical, or biologic threats was proposed. RESULTS:PLUS proposes that bladder health be defined as: "A complete state of physical, mental, and social well-being related to bladder function and not merely the absence of LUTS. Healthy bladder function permits daily activities, adapts to short-term physical or environmental stressors, and allows optimal well-being (e.g., travel, exercise, social, occupational, or other activities)." Definitions for each element of bladder function are reported with suggested subjective and objective measures. CONCLUSIONS:PLUS used a comprehensive transdisciplinary process to develop a bladder health definition. This will inform instrument development for evaluation of bladder health promotion and prevention of LUTS in research and public health initiatives