Development of surface bypass and collection at Rocky Reach Dam, Columbia River

Between 1985 and 1994, Chelan County Public Utility District (Chelan) used floatingrotating and passive diversion screens in the turbine intakes of Rocky Reach Dam to guide fishaway from the turbines and around the dam. Guidance efficiency of the diversion screen systemwas insufficient, rarely exceeding 25% of the total fish entering the turbine intakes. As a result,Chelan pursued the concept of surface collection based primarily on the success of spillwaybaffles at Wells Dam. Chelan tested a prototype surface collector in 1995 to see if the conceptwas feasible at Rocky Reach. Approximately 900, 000 juvenile fish passed through theprototype. Chelan concluded the concept of surface collection at Rocky Reach was feasible. In1996, we extended the floor of the surface collector upstream and added a sloping wall.Hydraulic and mathematical modelling showed that the new sloping wall and floor extensionnegatively affected the direction of water flow into the entrance of the collector. We removed theextended floor and sloping wall before the 2997 field season. In 1996, we observedapproximately 30% of the radio-tagged steelhead that entered the entrance of the collectorproceeded all the way through. In 1997, the percentage increased to 73%. The passiveintegrated transponder tag study in 1996 showed that approximately 25% of the juvenile Chinookand steelhead were guided by the fish bypass system. In 1997, the percentage improved to 47%The hybrid fish passage system (surface collector and diversion screens) appears to be thepreferred method for juvenile salmonid bypass at Rocky Reach Dam in the future

Factors that influence the downstream migration rates of juvenile salmon and steelhead through the hydroelectric system in the mid-Columbia River basin

We investigated the extent to which key factors influenced the migration rate of the smolts of Pacific salmon Oncorhynchus spp. through impounded portions of the mid-Columbia River, during the years 1989–1995. Actively migrating chinook salmon O. tshawytscha (oceantype and stream-type forms), sockeye salmon O. nerka, and steelhead O. mykiss were analyzed by bivariate and multiple-regression methods. The dependent variable was the rate (km/d) at which uniquely coded PIT-tagged (passive integrated transponder tags) smolts migrated between Rock Island Dam and McNary Dam. Predictor variables consisted of indices of river discharge volume (flow), water temperature, release date of tagged fish, and fish size. The variable of key interest was flow because water management strategies are in place to increase water velocity through flow augmentation, with the intention of increasing smolt migration rate to decrease smolt mortality. For spring-migrating sockeye salmon, hatchery steelhead, and wild steelhead, flow was the primary predictor variable entering the models, and the bivariate models explained 42, 36 and 31% of the observed variation in migration rate for those species, respectively. Yearling chinook salmon migration rate was not correlated with any variable. Summer-migrating ocean-type chinook salmon showed no response to flow over a broad range of discharge (1,500–5,000 m3/s). However, there was a positive relationship between migration rate and fish length at the time of tagging for oceantype chinook salmon; r 2 in the bivariate model = 0.59. Implications of these findings to water management strategies are discussed

Estimating in-river survival of migrating salmonid smolts using radiotelemetry

1987-199

Distance to available services for newborns at facilities in Malawi: A secondary analysis of survey and health facility data

BACKGROUND: Malawi has halved the neonatal mortality rate between 1990-2018, however, is not on track to achieve the Sustainable Development Goal 12 per 1,000 live births. Despite a high facility birth rate (91%), mother-newborn dyads may not remain in facilities long enough to receive recommended care and quality of care improvements are needed to reach global targets. Physical access and distance to health facilities remain barriers to quality postnatal care. METHODS: Using data We used individual data from the 2015-16 Malawi Demographic and Health Survey and facility data from the 2013-14 Malawi Service Provision Assessment, linking households to all health facilities within specified distances and travel times. We calculated service readiness scores for facilities to measure their capacity to provide birth/newborn care services. We fitted multi-level regression models to evaluate the association between the service readiness and appropriate newborn care (receiving at least five of six interventions). RESULTS: Households with recent births (n = 6010) linked to a median of two birth facilities within 5-10 km and one facility within a two-hour walk. The maximum service environment scores for linked facilities median was 77.5 for facilities within 5-10 km and 75.5 for facilities within a two-hour walk. While linking to one or more facilities within 5-10km or a two-hour walk was not associated with appropriate newborn care, higher levels of service readiness in nearby facilities was associated with an increased risk of appropriate newborn care. CONCLUSIONS: Women's choice of nearby facilities and quality facilities is limited. High quality newborn care is sub-optimal despite high coverage of facility birth and some newborn care interventions. While we did not find proximity to more facilities was associated with increased risk of appropriate care, high levels of service readiness was, showing facility birth and improved access to well-prepared facilities are important for improving newborn care

Cognitive and functional performance and plasma biomarkers of early Alzheimer's disease in Down syndrome.

IntroductionPeople with Down syndrome (DS) have a 75% to 90% lifetime risk of Alzheimer's disease (AD). AD pathology begins a decade or more prior to onset of clinical AD dementia in people with DS. It is not clear if plasma biomarkers of AD pathology are correlated with early cognitive and functional impairments in DS, and if these biomarkers could be used to track the early stages of AD in DS or to inform inclusion criteria for clinical AD treatment trials.MethodsThis large cross-sectional cohort study investigated the associations between plasma biomarkers of amyloid beta (Aβ)42/40, total tau, and neurofilament light chain (NfL) and cognitive (episodic memory, visual-motor integration, and visuospatial abilities) and functional (adaptive behavior) impairments in 260 adults with DS without dementia (aged 25-81 years).ResultsIn general linear models lower plasma Aβ42/40 was related to lower visuospatial ability, higher total tau was related to lower episodic memory, and higher NfL was related to lower visuospatial ability and lower episodic memory.DiscussionPlasma biomarkers may have utility in tracking AD pathology associated with early stages of cognitive decline in adults with DS, although associations were modest.HighlightsPlasma Alzheimer's disease (AD) biomarkers correlate with cognition prior to dementia in Down syndrome.Lower plasma amyloid beta 42/40 was related to lower visuospatial abilities.Higher plasma total tau and neurofilament light chain were associated with lower cognitive performance.Plasma biomarkers show potential for tracking early stages of AD symptomology