The Flushing Flow Problem: Defining and Evaluating Objectives

Reservoir releases may be specified for the purpose of maintaining or improving the downstream channel and habitat. A wide variety of ecological or management objectives may be defined for such flushing flows (which may be broadly divided into sediment maintenance and channel maintenance flows). To specify a particular discharge and water volume for a flushing flow requires that the ecological or management objectives be translated into specific physical objectives for which flows can be specified. Flushing objectives that cannot be translated into definable flows are of little practical use, regardless of their intrinsic importance. Once defined, flushing flow objectives may be shown to conflict in some cases. For example, no flushing flow can satisfy the typical sediment maintenance objectives of maximizing sand removal and minimizing gravel loss. A discharge that mobilizes sediment throughout the channel cross section for channel maintenance purposes will often produce comparable transport rates of sand and gravel, thereby eliminating the selective transport of sand needed to reduce the sand content in the bed. Some nonflushing alternatives, such as artificial gravel replenishment and pool dredging, can be used to improve the performance of flushing flows. Selection among these alternatives and specification of a flushing flow discharge and volume depend directly on quantitative estimates of sand and gravel transport as a function of flow rate and volume

A Model to Predict the Evolution of a Gravel Bed River Under an Imposed Cyclic Hydrograph and its Application to the Trinity River

Major changes in the morphology of the Trinity River in California, such as narrowing of the cross section and sedimentation of fine sediment in pools, occurred after the closure of a system of dams. These changes caused a dramatic reduction in the salmonid population and a resulting decline of the fishery. Gravel augmentation, regulated flood releases, and mechanical channel rehabilitation are currently being implemented to help restore the aquatic habitat of the river. The present paper describes a tool, named the Spawning Gravel Refresher, for designing and predicting the effects of gravel augmentation in gravel bed rivers. The tool assumes an imposed, cycled hydrograph. The model is calibrated and applied to the regulated reach of the Trinity River in four steps: (1) zeroing runs to reproduce conditions of mobile bed equilibrium as best can be estimated for the predam Trinity River, (2) runs to compare the predictions with the results of previous studies, (3) runs at an engineering time scale to reproduce the effects of the dams, and (4) runs to design gravel augmentation schemes. In the fourth group of runs, the combined effects of engineered flood flow releases and gravel augmentation are predicted. At an engineering time scale, the model indicates that the fraction of fine sediment in the surface layer and in the topmost part of the substrate should decrease when subjected to these two restoration measures, with a consequent improvement of the quality of the spawning gravel

Lack of awareness of symptoms in people with dementia: the structural and functional basis

Objective: To review studies investigating the brain correlates of unawareness of cognitive and behavioural symptoms in people with dementia. Design: A detailed search of the literature was conducted to include all the peer-reviewed studies published in English aimed at identifying the structural or functional brain correspondents of unawareness in dementia patients. Their results were interpreted in relation to the methodological differences in terms of type of dementia studied, the protocol adopted to measure lack of awareness, the imaging techniques employed, the experimental designs and statistical analyses performed. Results: Eighteen studies undertaken to explore the functional and structural correlates of unawareness of cognitive symptoms in dementia were identified. Although their results showed a disparate range of brain correlates, they were mainly localized in frontal and temporo-parietal regions. Conclusions: Although the anatomical correlates of unawareness of disease in dementia have not yet been exhaustively explored, understanding the correlates of unawareness may also contribute to understand the brain correlates of self-awareness and self-reflection. We discuss the current knowledge base and consider potential future directions for research

Surface-enhanced Raman scattering from surface and subsurface oxygen species at microscopically well-defined Ag surfaces

Ag(111) and Ag(110) surfaces exposed to oxygen at elevated temperatures (∼800 K) exhibit strongly enhanced Raman bands at 803 and 627 cm−1 which are attributed to O atoms strongly chemisorbed on the surface (Oγ) or held in subsurface sites (Oβ), respectively. In contrast to usual experience, surface-enhanced Raman scattering is occurring here under well-defined conditions up to temperatures of 900 K which is attributed to the joint operation of delocalized electromagnetic enhancement (caused by surface roughness provided by oxygen-induced faceting) and local resonance due to the particular electronic properties of the surface sites

Lithium Treatment of APPSwDI/NOS2−/− Mice Leads to Reduced Hyperphosphorylated Tau, Increased Amyloid Deposition and Altered Inflammatory Phenotype

Lithium is an anti-psychotic that has been shown to prevent the hyperphosphorylation of tau protein through the inhibition of glycogen-synthase kinase 3-beta (GSK3β). We recently developed a mouse model that progresses from amyloid pathology to tau pathology and neurodegeneration due to the genetic deletion of NOS2 in an APP transgenic mouse; the APPSwDI/NOS2−/− mouse. Because this mouse develops tau pathology, amyloid pathology and neuronal loss we were interested in the effect anti-tau therapy would have on amyloid pathology, learning and memory. We administered lithium in the diets of APPSwDI/NOS2−/− mice for a period of eight months, followed by water maze testing at 12 months of age, immediately prior to sacrifice. We found that lithium significantly lowered hyperphosphorylated tau levels as measured by Western blot and immunocytochemistry. However, we found no apparent neuroprotection, no effect on spatial memory deficits and an increase in histological amyloid deposition. Aβ levels measured biochemically were unaltered. We also found that lithium significantly altered the neuroinflammatory phenotype of the brain, resulting in enhanced alternative inflammatory response while concurrently lowering the classical inflammatory response. Our data suggest that lithium may be beneficial for the treatment of tauopathies but may not be beneficial for the treatment of Alzheimer's disease

Remote primary care consultations for people living with dementia during the COVID-19 pandemic: experiences of people living with dementia and their carers

BACKGROUND: COVID-19 has accelerated remote healthcare provision in primary care, with changes potentially permanent. The implementation of remote provision of healthcare needs to hear from vulnerable populations, such as people living with dementia. AIM: To understand the remote healthcare experiences of patients living with dementia and their family carers during the COVID-19 pandemic. DESIGN AND SETTING: Qualitative interviews with community-based patients living with dementia and their carers during early months (May-August 2020) of the COVID-19 pandemic in England. METHODS: Semi-structured interviews were conducted remotely by telephone or video call with 30 patients living with dementia and 31 carers. Data were analysed using thematic analysis. RESULTS: Three main themes were derived relating to: 1) proactive care at the onset of COVID-19 restrictions, 2) avoidance of healthcare settings and services, and 3) difficulties with remote healthcare encounters. People living with dementia and their carers felt check-up calls were reassuring but limited in scope and content. Some avoided healthcare services, wishing to minimise COVID-19 risk, reduce NHS burden, or encountering technological barriers. Difficulties in remote consultations included lack of prompts to remember problems, dealing with new emerging problems, rescheduling/missed calls, and inclusion of the person with dementia's voice. CONCLUSION: While remote consultations could be effective, pro-active calls could be more structured around needs, and consideration should be given to replace non-verbal prompts to describe problems, particularly for new health concerns. In continuing remote consultations, it is important to facilitate engagement with patients living with dementia and their carers to ensure best practice

Diverse inflammatory responses in transgenic mouse models of Alzheimer's disease and the effect of immunotherapy on these responses

While the presence of an inflammatory response in AD (Alzheimer's disease) is well known, the data on inflammation are conflicting, suggesting that inflammation either attenuates pathology, exacerbates it or has no effect. Our goal was to more fully characterize the inflammatory response in APP (amyloid precursor protein) transgenic mice with and without disease progression. In addition, we have examined how anti-Aβ (amyloid β-peptide) immunotherapy alters this inflammatory response. We have used quantitative RT–PCR (reverse transcription–PCR) and protein analysis to measure inflammatory responses ranging from pro-inflammatory to anti-inflammatory and repair factors in transgenic mice that develop amyloid deposits only (APPSw) and amyloid deposits with progression to tau pathology and neuron loss [APPSw/NOS2−/− (nitric oxide synthase 2−/−)]. We also examined tissues from previously published immunotherapy studies. These studies were a passive immunization study in APPSw mice and an active vaccination study in APPSw/NOS2−/− mice. Both studies have already been shown to lower amyloid load and improve cognition. We have found that amyloid deposition is associated with high expression of alternative activation and acquired deactivation genes and low expression of pro-inflammatory genes, whereas disease progression is associated with a mixed phenotype including increased levels of some classical activation factors. Immunotherapy targeting amyloid deposition in both mouse models resulted in decreased alternative inflammatory markers and, in the case of passive immunization, a transient increase in pro-inflammatory markers. Our results suggest that an alternative immune response favours retention of amyloid deposits in the brain, and switching away from this state by immunotherapy permits removal of amyloid

Exploring how triads of people living with dementia, carers and health care professionals function in dementia health care: A systematic qualitative review and thematic synthesis

BACKGROUND: Many qualitative studies report the post-diagnostic care experiences of carers and people living with dementia; however, this is not often accompanied by opportunities to hear the corresponding views of their health care professionals and how this triadic relationship functions. The aim of this review was to identify and thematically synthesize the experiences of health care services reported by people living with dementia, their carers and health care professionals. METHODS: Medline, PsycINFO, Embase and CINAHL were searched from inception to 31 July 2019 for qualitative research including people living with dementia, carers and health care professionals. Data were coded and thematically synthesised using NVivo. RESULTS: Medline, PsycINFO, Embase and CINAHL were searched from inception to 31 July 2019 for qualitative research including people living with dementia, carers and health care professionals. Data were coded and thematically synthesised using NVivo. DISCUSSION: The interactions and complexity of triadic dementia care relationships further our understanding of how to improve dementia care. Awareness of possible diverging attitudes highlights areas of necessary improvement and further research into facilitating engagement, such as when multiple professionals are involved or where there are mismatched expectations of the roles of triad members. In order to operate efficiently as a triad member, professionals should be aware of how pre-existing relations can influence the composition of a triad, encourage the involvement of the person living with dementia, clarify the expectations of all parties, establish trusting relationships and enable communication within the direct triad and beyond