2,312 research outputs found

    Chinook habitat restoration decision support tool- Identifying chinook salmon habitat restoration effectiveness based on temperature, flow, and bioenergetics models

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    Stream restoration projects focus on improving habitat for Pacific Salmonids in watersheds throughout the Pacific Northwest. Currently, few comprehensive tools are available for managers to mechanistically predict the improved fish growth that comes with restoration actions, such as riparian acquisitions, riparian planting or levee setbacks. Therefore, managers need tools that can predict salmonid growth potential given different decision scenarios. One approach to address the Puget Sound Partnership’s regional chinook recovery goals would be a linked stream temperature, flow, and fish bioenergetics model that predict chinook growth benefits of different remediation strategies. Considered strategies will include changes to riparian habitat and instream flows. Increasingly, it is recognized that riparian restoration also benefits salmonids through the increased terrestrial food supply. Such a modeling tool, or model-ensemble, would provide at least a two-tiered application. Screening-level predictions of stream temperatures and chinook growth might be based on currently available input data, i.e., widespread estimates from SNTemp and NHD+ model outputs, and reported food availability and diets. A second, more specific model-ensemble output based on segment specific data, much of it currently available, would require a few, relatively minor site-specific values, namely widths, depths, substrate and invertebrate drift. The effectiveness of the decision support modeling tool could be demonstrated at a handful of sites across a range of land uses and watershed sizes with currently available data. This tool would allow managers the ability to predict and compare chinook growth for current and future conditions from different remediation decisions along a specified river reach. Additionally, conducting a sensitivity analysis with the tool, or model-ensemble, will identify essential information needs for more detailed, and improved, site-specific estimates of chinook growth. Such a tool could scale up to generate region-wide maps of potential chinook growth as more Salish Sea-wide temperature, flow, habitat and drift data becomes available

    Assessment of Spectral Doppler in Preclinical Ultrasound Using a Small-Size Rotating Phantom

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    Preclinical ultrasound scanners are used to measure blood flow in small animals, but the potential errors in blood velocity measurements have not been quantified. This investigation rectifies this omission through the design and use of phantoms and evaluation of measurement errors for a preclinical ultrasound system (Vevo 770, Visualsonics, Toronto, ON, Canada). A ray model of geometric spectral broadening was used to predict velocity errors. A small-scale rotating phantom, made from tissue-mimicking material, was developed. True and Doppler-measured maximum velocities of the moving targets were compared over a range of angles from 10° to 80°. Results indicate that the maximum velocity was overestimated by up to 158% by spectral Doppler. There was good agreement (50%). The phantom is capable of validating the performance of blood velocity measurement in preclinical ultrasound

    Better Nonlinear Models from Noisy Data: Attractors with Maximum Likelihood

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    A new approach to nonlinear modelling is presented which, by incorporating the global behaviour of the model, lifts shortcomings of both least squares and total least squares parameter estimates. Although ubiquitous in practice, a least squares approach is fundamentally flawed in that it assumes independent, normally distributed (IND) forecast errors: nonlinear models will not yield IND errors even if the noise is IND. A new cost function is obtained via the maximum likelihood principle; superior results are illustrated both for small data sets and infinitely long data streams.Comment: RevTex, 11 pages, 4 figure

    A protocol for improved measurement of arterial flow rate in preclinical ultrasound

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    PURPOSE: To describe a protocol for the measurement of blood flow rate in small animals and to compare flow rate measurements against measurements made using a transit time flowmeter. MATERIALS AND METHODS: Measurements were made in rat and mice using a Visualsonics Vevo 770 scanner. The flow rate in carotid and femoral arteries was calculated from the time-average maximum velocity and vessel diameter. A correction factor was applied to correct for the overestimation of velocity arising from geometric spectral broadening. Invasive flow rate measurements were made using a Transonics system. RESULTS: Measurements were achieved in rat carotid and femoral arteries and in mouse carotid arteries. Image quality in the mouse femoral artery was too poor to obtain diameter measurements. The applied correction factor in practice was 0.71–0.77. The diameter varied by 6–18% during the cardiac cycle. There was no overall difference in the flow rate measured using ultrasound and using transit-time flowmeters. The flow rates were comparable with those previously reported in the literature. There was wide variation in flow rates in the same artery in individual animals. Transit-time measurements were associated with changes of a factor of 10 during the typical 40 min measurement period, associated with probe movement, vessel spasm, vessel kinking and other effects. CONCLUSION: A protocol for the measurement of flow rate in arteries in small animals has been described and successfully used in rat carotid and femoral arteries and in mouse carotid arteries. The availability of a noninvasive procedure for flow rate measurement avoids the problems with changes in flow associated with an invasive procedure

    Polygenic overlap between schizophrenia risk and antipsychotic response: a genomic medicine approach

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    Therapeutic treatments for schizophrenia do not alleviate symptoms for all patients and efficacy is limited by common, often severe, side-effects. Genetic studies of disease can identify novel drug targets, and drugs for which the mechanism has direct genetic support have increased likelihood of clinical success. Large-scale genetic studies of schizophrenia have increased the number of genes and gene sets associated with risk. We aimed to examine the overlap between schizophrenia risk loci and gene targets of a comprehensive set of medications to potentially inform and improve treatment of schizophrenia

    Associations between cardiorespiratory fitness, physical activity and clustered cardiometabolic risk in children and adolescents: the HAPPY study

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    Clustering of cardiometabolic risk factors can occur during childhood and predisposes individuals to cardiometabolic disease. This study calculated clustered cardiometabolic risk in 100 children and adolescents aged 10-14 years (59 girls) and explored differences according to cardiorespiratory fitness (CRF) levels and time spent at different physical activity (PA) intensities. CRF was determined using a maximal cycle ergometer test, and PA was assessed using accelerometry. A cardiometabolic risk score was computed as the sum of the standardised scores for waist circumference, blood pressure, total cholesterol/high-density lipoprotein ratio, triglycerides and glucose. Differences in clustered cardiometabolic risk between fit and unfit participants, according to previously proposed health-related threshold values, and between tertiles for PA subcomponents were assessed using ANCOVA. Clustered risk was significantly lower (p < 0.001) in the fit group (mean 1.21 ± 3.42) compared to the unfit group (mean -0.74 ± 2.22), while no differences existed between tertiles for any subcomponent of PA. Conclusion These findings suggest that CRF may have an important cardioprotective role in children and adolescents and highlights the importance of promoting CRF in youth

    An integrated genomic analysis of anaplastic meningioma identifies prognostic molecular signatures.

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    Anaplastic meningioma is a rare and aggressive brain tumor characterised by intractable recurrences and dismal outcomes. Here, we present an integrated analysis of the whole genome, transcriptome and methylation profiles of primary and recurrent anaplastic meningioma. A key finding was the delineation of distinct molecular subgroups that were associated with diametrically opposed survival outcomes. Relative to lower grade meningiomas, anaplastic tumors harbored frequent driver mutations in SWI/SNF complex genes, which were confined to the poor prognosis subgroup. Aggressive disease was further characterised by transcriptional evidence of increased PRC2 activity, stemness and epithelial-to-mesenchymal transition. Our analyses discern biologically distinct variants of anaplastic meningioma with prognostic and therapeutic significance

    Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup

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    Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD
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