470 research outputs found
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Effects of Hyporheic Exchange Flows on Egg Pocket Water Temperature in Snake River Fall Chinook Salmon Spawning Areas, 2002-2003 Final Report.
The development of the Snake River hydroelectric system has affected fall Chinook salmon smolts by shifting their migration timing to a period (mid- to late-summer) when downstream reservoir conditions are unfavorable for survival. Subsequent to the Snake River Chinook salmon fall-run Evolutionary Significant Unit being listed as Threatened under the Endangered Species Act, recovery planning has included changes in hydrosystem operations (e.g., summer flow augmentation) to improve water temperature and flow conditions during the juvenile Chinook salmon summer migration period. In light of the limited water supplies from the Dworshak reservoir for summer flow augmentation, and the associated uncertainties regarding benefits to migrating fall Chinook salmon smolts, additional approaches for improved smolt survival need to be evaluated. This report describes research conducted by the Pacific Northwest National Laboratory (PNNL) that evaluated relationships among river discharge, hyporheic zone characteristics, and egg pocket water temperature in Snake River fall Chinook salmon spawning areas. This was a pilot-scale study to evaluate these relationships under existing operations of Hells Canyon Dam (i.e., without any prescribed manipulations of river discharge) during the 2002-2003 water year. The project was initiated in the context of examining the potential for improving juvenile Snake River fall Chinook salmon survival by modifying the discharge operations of Hells Canyon Dam. The potential for improved survival would be gained by increasing the rate at which early life history events proceed (i.e., incubation and emergence), thereby allowing smolts to migrate through downstream reservoirs during early- to mid-summer when river conditions are more favorable for survival. PNNL implemented this research project at index sites throughout 160 km of the Hells Canyon Reach (HCR) of the Snake River. The HCR extends from Hells Canyon Dam (river kilometer [rkm] 399) downstream to the upper end of Lower Granite Reservoir near rkm 240. We randomly selected 14 fall Chinook salmon spawning locations as study sites, which represents 25% of the most used spawning areas throughout the HCR. Interactions between river water and pore water within the riverbed (i.e., hyporheic zone) at each site were quantified through the use of self-contained temperature and water level data loggers suspended inside of piezometers. Surrounding the piezometer cluster at each site were 3 artificial egg pockets. In mid-November 2002, early-eyed stage fall Chinook salmon eggs were placed inside of perforated polyvinyl chloride (PVC) tubes, along with a temperature data logger, and buried within the egg pockets. Fall Chinook salmon eggs were also incubated in the laboratory for the purpose of developing growth curves that could be used as indicators of emergence timing. The effects of discharge on vertical hydrologic exchange between the river and riverbed were inferred from measured temperature gradients between the river and riverbed, and the application of a numerical model. The hydrologic regime during the 2002-2003 sampling period exhibited one of the lowest, most stable daily discharge patterns of any of the previous 12 water years. The vertical hydraulic gradients (VHG) between the river and the riverbed suggested the potential for predominantly small magnitude vertical exchange. The VHG also showed little relationship to changes in river discharge at most sites. Despite the relatively small vertical hydraulic gradients at most sites, results from the numerical modeling of riverbed pore water velocity and hyporheic zone temperatures suggested that there was significant vertical hydrologic exchange during all time periods. The combined results of temperature monitoring and numerical modeling indicate that only 2 of 14 sites were significantly affected by short-term (hourly to daily) large magnitude changes in discharge. Although the two sites exhibited acute flux reversals between river water and hyporheic water resulting from short-term large magnitude changes in discharge, these flux reversals had minimal effect on emergence timing estimates. Indeed, the emergence timing estimates at all sites were largely unaffected by the changes in river stage resulting from hydropower operations at Hells Canyon Dam. Our results indicate that the range of emergence timing estimates due to differences among the eggs from different females can be as large as or larger than the emergence timing estimates due to site differences (i.e., bed temperatures among sites). We conclude that during the 2002-2003 fall Chinook salmon incubation period, hydropower operations of Hells Canyon Dam had an insignificant effect on fry emergence timing at the study sites
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Effects of Hydroelectric Dam Operations on the Restoration Potential of Snake River Fall Chinook Salmon (Oncorhynchus tshawytscha) Spawning Habitat Final Report, October 2005 - September 2007.
This report describes research conducted by the Pacific Northwest National Laboratory for the Bonneville Power Administration (BPA) as part of the Fish and Wildlife Program directed by the Northwest Power and Conservation Council. The study evaluated the restoration potential of Snake River fall Chinook salmon spawning habitat within the impounded lower Snake River. The objective of the research was to determine if hydroelectric dam operations could be modified, within existing system constraints (e.g., minimum to normal pool levels; without partial removal of a dam structure), to increase the amount of available fall Chinook salmon spawning habitat in the lower Snake River. Empirical and modeled physical habitat data were used to compare potential fall Chinook salmon spawning habitat in the Snake River, under current and modified dam operations, with the analogous physical characteristics of an existing fall Chinook salmon spawning area in the Columbia River. The two Snake River study areas included the Ice Harbor Dam tailrace downstream to the Highway 12 bridge and the Lower Granite Dam tailrace downstream approximately 12 river kilometers. These areas represent tailwater habitat (i.e., riverine segments extending from a dam downstream to the backwater influence from the next dam downstream). We used a reference site, indicative of current fall Chinook salmon spawning areas in tailwater habitat, against which to compare the physical characteristics of each study site. The reference site for tailwater habitats was the section extending downstream from the Wanapum Dam tailrace on the Columbia River. Fall Chinook salmon spawning habitat use data, including water depth, velocity, substrate size and channelbed slope, from the Wanapum reference area were used to define spawning habitat suitability based on these variables. Fall Chinook salmon spawning habitat suitability of the Snake River study areas was estimated by applying the Wanapum reference reach habitat suitability criteria to measured and modeled habitat data from the Snake River study areas. Channel morphology data from the Wanapum reference reach and the Snake River study areas were evaluated to identify geomorphically suitable fall Chinook salmon spawning habitat. The results of this study indicate that a majority of the Ice Harbor and Lower Granite study areas contain suitable fall Chinook salmon spawning habitat under existing hydrosystem operations. However, a large majority of the currently available fall Chinook salmon spawning habitat in the Ice Harbor and Lower Granite study areas is of low quality. The potential for increasing, through modifications to hydrosystem operations (i.e., minimum pool elevation of the next downstream dam), the quantity or quality of fall Chinook salmon spawning habitat appears to be limited. Estimates of the amount of potential fall Chinook salmon spawning habitat in the Ice Harbor study area decreased as the McNary Dam forebay elevation was lowered from normal to minimum pool elevation. Estimates of the amount of potential fall Chinook salmon spawning habitat in the Lower Granite study area increased as the Little Goose Dam forebay elevation was lowered from normal to minimum pool elevation; however, 97% of the available habitat was categorized within the range of lowest quality. In both the Ice Harbor and Lower Granite study areas, water velocity appears to be more of a limiting factor than water depth for fall Chinook salmon spawning habitat, with both study areas dominated by low-magnitude water velocity. The geomorphic suitability of both study areas appears to be compromised for fall Chinook salmon spawning habitat, with the Ice Harbor study area lacking significant bedforms along the longitudinal thalweg profile and the Lower Granite study area lacking cross-sectional topographic diversity. To increase the quantity of available fall Chinook salmon spawning habitat in the Ice Harbor and Lower Granite study area, modifications to hydroelectric dam operations beyond those evaluated in this study likely would be necessary. Modifications may include operational and structural changes, such as lowering downstream dam forebay elevations to less than minimum pool. There is a large amount of uncertainty as to whether or not such modifications could increase the quantity of available fall Chinook salmon spawning habitat in the Ice Harbor and Lower Granite study area. The results from this study provide some certainty that the quantity and quality of fall Chinook salmon spawning habitat within the lower Snake River are not likely to be increased within the existing hydroelectric dam operations
mHealth Support to Stimulate Physical Activity in Individuals With Intellectual Disability: Protocol for a Mixed Methods Pilot Study
Background: Several studies have shown that individuals with intellectual disabilities (IDs) have low levels of physical activity
(PA), and intervention studies on PA suggest inconsistent evidence. The use of technology as a means of motivation for PA has
yet to be extensively explored and needs to be further investigated.
Objective: We aim to assess the feasibility and acceptability of procedures for an intervention arm in a future trial on mobile
health (mHealth) to support PA for individuals with IDs. In addition, we aim to examine how the use of technology can influence
motivation for PA among participants, their caregivers, and staff members.
Methods: A mixed methods pilot study of an intervention arm will be carried out in a planned randomized controlled trial
(RCT). Ten participants with ID and their caregivers or a staff member will be included. Information will always be provided by
a caregiver or a staff member, or participants with ID if possible. Assessments will be carried out at baseline, follow-up after 4
weeks, and 12 weeks, and include questionnaires on PA, social support, self-efficacy, and challenging behavior. PA will be
measured with 2 different activity trackers (Fitbit and Axivity) for 1 week at all assessments. Feasibility will be assessed as
recruitment and adherence rate, missing data, usability of the motivational mHealth tool, and estimates of effectiveness. Acceptability
of study procedures, activity measures, and motivation for participation in PA will be additionally assessed with qualitative
methods at the end of the intervention.
Results: Enrollment commenced in May 2021. Data collection was completed in March 2022.
Conclusions: This pilot study will evaluate the feasibility and acceptability of study procedures of the intervention arm of a
planned RCT to address feasibility issues, improve study procedures, and estimate effectiveness of the study measures. How the
use of technology can influence motivation for PA will also be examined, which can help guide and improve future PA interventions
involving the use of technology
Plant-derived recombinant F1, V, and F1-V fusion antigens of Yersinia pestis activate human cells of the innate and adaptive immune system
Plague is still endemic in different regions of the world. Current vaccines raise concern for their side effects and limited protection, highlighting the need for an efficacious and rapidly producible vaccine. F1 and V antigens of Yersinia pestis, and F1-V fusion protein produced in Nicotiana benthamiana administered to guinea pigs resulted in immunity and protection against an aerosol challenge of virulent h pestis. We examined the effects of plant-derived F1, V, and F1-V on human cells of the innate immunity. F1, V, and F1-V proteins engaged TLR2 signalling and activated IL-6 and CXCL-8 production by monocytes, without affecting the expression of TNF-alpha, IL-12, IL-10, IL-1 beta, and CXCL10. Native F1 antigen and recombinant plant-derived F1 (rF1) and rF1-V all induced similar specific T-cell responses, as shown by their recognition by T-cells from subjects who recovered from E pestis infection. Native F1 and rF1 were equally well recognized by serum antibodies of Y. pestis-primed donors, whereas serological reactivity to rF1-V hybrid was lower, and that to rV was virtually absent. In conclusion, plant-derived F1, V, and F1-V antigens are weakly reactogenic for human monocytes and elicit cell-mediated and humoral responses similar to those raised by Y pestis infection
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