Evaluation of visual survey methods for monitoring Pacific salmon (Oncorhynchus spp.) escapement in relation to conservation guidelines

2008 ◽  
Vol 65 (2) ◽  
pp. 212-226 ◽  
Author(s):  
Kendra R Holt ◽  
Sean P Cox

Canada’s Wild Salmon Policy requires that biological status of conservation units of Pacific salmon (Oncorhynchus spp.) be assessed regularly in relation to abundance-based benchmarks. Visual survey methods, in which periodic counts of spawning fish are made throughout a season, will likely be used for this purpose because they provide a cost-effective means of monitoring interannual trends in escapement. Trend detection performance for visual survey methods depends mainly upon consistency in (i) the ability of observers to detect fish and (ii) the annual timing of fish presence in the survey area. We developed a Monte Carlo simulation procedure to evaluate the ability of four visual survey methods (peak count, mean count, trapezoidal area-under-the-curve (AUC), and likelihood AUC) to detect 30% declines in coho salmon (Oncorhynchus kisutch) escapement over 10 years (i.e., the magnitude of trend that would warrant listing a coho population as threatened using the listing criteria of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC)) given realistic levels of variability in these two factors. The mean count outperformed all other approaches across a wide range of scenarios about true population dynamics and survey designs, suggesting that a simple mean count method is suitable for monitoring coho escapements in relation to COSEWIC guidelines.

Geophysics ◽  
2014 ◽  
Vol 79 (4) ◽  
pp. T243-T255 ◽  
Author(s):  
James W. D. Hobro ◽  
Chris H. Chapman ◽  
Johan O. A. Robertsson

We present a new method for correcting the amplitudes of arrivals in an acoustic finite-difference simulation for elastic effects. In this method, we selectively compute an estimate of the error incurred when the acoustic wave equation is used to approximate the behavior of the elastic wave equation. This error estimate is used to generate an effective source field in a second acoustic simulation. The result of this second simulation is then applied as a correction to the original acoustic simulation. The overall cost is approximately twice that of an acoustic simulation but substantially less than the cost of an elastic simulation. Because both simulations are acoustic, no S-waves are generated, so dispersed converted waves are avoided. We tested the characteristics of the method on a simple synthetic model designed to simulate propagation through a strong acoustic impedance contrast representative of sedimentary geology. It corrected amplitudes to high accuracy for reflected arrivals over a wide range of incidence angles. We also evaluated results from simulations on more complex models that demonstrated that the method was applicable in realistic sedimentary models containing a wide range of seismic contrasts. However, its accuracy was reduced for wide-angle reflections from very high impedance contrasts such as a shallow top-salt interface. We examined the influence of modeling at coarse grid resolutions, in which converted S-waves in the equivalent elastic simulation are dispersed. These results provide some validation for the accuracy of the method when applied using finite-difference grids designed for acoustic modeling. The method appears to offer a cost-effective means of modeling elastic amplitudes for P-wave arrivals in a useful range of velocity models. It has several potential applications in imaging and inversion.


1985 ◽  
Vol 42 (12) ◽  
pp. 1986-1993 ◽  
Author(s):  
S. M. Bower ◽  
L. Margolis ◽  
R. J. MacKay

Susceptibility to the lethal effects of low levels of total residual chlorine (TRC) differed between juvenile coho salmon (Oncorhynchus kisutch) and the salmon leech (Piscicola salmositica), the vector for the haemoflagellate salmonid pathogen Cryptobia salmositica. There was no salmon mortality at concentrations below approximately 50 μg TRC/L for the maximum exposure time of 24 h. Some damage to gill tissue (hypertrophy, fusion, oedema, and some necrosis), was observed at the highest concentrations of TRC that did not kill any of the fish (approximately 50 μg/L for 24 h, and approximately 100 μg/L for 8 h). This damage was repaired by the fish within 4 d of exposure, although evidence of past irritation was noted in 6 of 12 fish. All small juvenile leeches exposed to 44 μg TRC/L for 24 h died, and over half of such leeches exposed to 44 μg/L for 8 h and 21 μg/L for 24 h died. Below TRC concentrations that were lethal to the fish (approximately 50 μg/L), contours of constant leech mortality derived from a logistic regression model fitted to the data offered a wide range of concentrations and exposure times that would result in high mortality of juvenile leeches. Larger subadult and adult leeches were more resistant to chlorine than the smaller leeches but were more sensitive than the juvenile fish. Thus, chlorine may prove useful for controlling P. salmositica in salmonid hatcheries.


Author(s):  
John R. Giudicessi ◽  
Matthew Schram ◽  
J. Martijn Bos ◽  
Connor D. Galloway ◽  
Jacqueline B. Shreibati ◽  
...  

Background: Heart rate-corrected QT interval (QTc) prolongation, whether secondary to drugs, genetics including congenital long QT syndrome (LQTS), and/or systemic diseases including SARS-CoV-2-mediated COVID19, can predispose to ventricular arrhythmias and sudden cardiac death. Currently, QTc assessment and monitoring relies largely on 12-lead electrocardiography. As such, we sought to train and validate an artificial intelligence (AI)-enabled 12-lead electrocardiogram (ECG) algorithm to determine the QTc, and then prospectively test this algorithm on tracings acquired from a mobile ECG (mECG) device in a population enriched for repolarization abnormalities. Methods: Using over 1.6 million 12-lead ECGs from 538,200 patients, a deep neural network (DNN) was derived (n = 250,767 patients for training and n = 107,920 patients for testing) and validated (n = 179,513 patients) to predict the QTc using cardiologist over-read QTc values as the gold standard. The ability of this DNN to detect clinically-relevant QTc prolongation (e.g. QTc ≥ 500 ms) was then tested prospectively on 686 genetic heart disease (GHD) patients (50% with LQTS) with QTc values obtained from both a 12-lead ECG and a prototype mECG device equivalent to the commercially-available AliveCor KardiaMobile 6L. Results: In the validation sample, strong agreement was observed between human over-read and DNN-predicted QTc values (-1.76 ± 23.14 ms). Similarly, within the prospective, GHD-enriched dataset, the difference between DNN-predicted QTc values derived from mECG tracings and those annotated from 12-lead ECGs by a QT expert (-0.45 ± 24.73 ms) and a commercial core ECG laboratory [+10.52 ms ± 25.64 ms] was nominal. When applied to mECG tracings, the DNN's ability to detect a QTc value ≥ 500 ms yielded an area under the curve, sensitivity, and specificity of 0.97, 80.0%, and 94.4%, respectively. Conclusions: Using smartphone-enabled electrodes, an AI-DNN can predict accurately the QTc of a standard 12-lead ECG. QTc estimation from an AI-enabled mECG device may provide a cost-effective means of screening for both acquired and congenital LQTS in a variety of clinical settings where standard 12-lead electrocardiography is not accessible or cost-effective.


Author(s):  
Daniel B. Hess ◽  
Brian D. Taylor ◽  
Allison C. Yoh

Bus rapid transit (BRT) is growing rapidly in popularity because it is viewed widely as an efficient and effective means to improve both transit service and patronage. This paper argues that two distinct views of BRT are emerging: ( a) BRT as a new form of high-speed, rubber-tired, rail-like rapid transit and ( b) BRT as a cost-effective way to upgrade both the quality and image of traditional fixed-route bus service. These two views carry different price tags because the cost of planning, constructing, and operating BRT depends on the complexity of new service features and on rises for BRT that offer service characteristics approaching those of light rail. This study fills a gap in the literature on the costs of BRT by examining in detail component costs–-actual costs for recently implemented services and projected costs for planned new services–-for a sample of BRT systems in North American cities. The study examined BRT costs of 14 planned and recently opened BRT systems to determine how the wide range of BRT service and technology configurations affect costs. The study found that although some of the most successful and popular new BRT systems are high-quality services operating in mixed traffic and implemented at relatively low cost, most BRT projects on the drawing boards are more elaborate, more expensive systems than many currently in service. Most new BRT projects emphasize elaborate LRT-type improvements to lines and stations in one or a few corridors rather than less splashy improvements (such as next-bus monitors, signal preemption, queue-jump lanes, and so forth) affecting more lines and modes in local transit networks. Among the 14 systems examined here, most could be characterized as light rail lite.


1986 ◽  
Vol 43 (10) ◽  
pp. 1946-1959 ◽  
Author(s):  
L B. Holtby ◽  
M. C. Healey

Several recent studies have presented evidence that large size confers a selective advantage to female Pacific salmon. Nevertheless, a wide range of female sizes is normally present in any spawning population. Two possible explanations exist for the observed range in female size. First, average female size might be determined by an optimizing process with variation around the optimum size due to individual differences in success at obtaining food. Second, various sizes of females might coexist as a mixed evolutionary stable strategy. Under the first explanation, females of sizes other than the optimum would display lower fitness whereas, under the second explanation, females of all sizes would be equally fit. We investigated factors affecting survival of eggs, fry, and smolts of coho salmon (Oncorhynchus kisutch) in Carnation Creek on Vancouver Island with a view to determining the relative fitness of different sized females. Egg-to-fry mortality was best explained by a model that included only the effects of stream bed scour and gravel quality. Including an effect of female size, expressed through depth of egg burying, worsened the model's predictive capability. We could find no evidence that the eggs of large females consistently survived better during incubation than those of small females. In fact, we observed three instances in which it appeared that the eggs of small females survived better. In Carnation Creek, large 1- and 2-yr-old smolts did not consistently survive better in the marine environment than small smolts. Thus, we were unable to demonstrate that the reproductive success of large females was consistently higher than that of small females, contrary to the hypothesis that female size is the result of an optimizing process. In Carnation Creek the observed range of female sizes probably represents an evolutionary stable strategy in which all sizes have equal fitness. We propose a model that predicts female size and variance in size based on the conflicting selective effects of gravel quality, scour, and competition for nest sites.


Author(s):  
Justin Langdon ◽  
Steve C. Southward

This paper discusses the development of an improved design for a tire-coupled quarter-vehicle testing rig. The use of indoor-based simulation tools has become a mainstay in vehicle testing for the automotive and motorsports industries. Testing on a quarter-vehicle rig provides a cost effective means for making accurate and repeatable measurements that enables the user to perform a relatively large number of tests in a short amount of time. A review of current quarter-vehicle test platforms, both commercially available and in academic research labs, indicated that many desired functional requirements were not available. The goal of this effort was to develop a new quarter-vehicle rig with expanded capabilities that are not simultaneously present in the current state-of-the-art. The desired functional requirements are: accommodation of a wide range of actual vehicle suspension components including the tire and wheel, weight transfer due to braking and acceleration, aerodynamic forces, and vehicle roll. The test rig was constructed and tested using a Porsche 996 suspension. The suspension dynamics were characterized by fitting the parameters of a linear dynamic model to experimental response data from the rig. The design and performance of this new quarter-vehicle test rig is shown to be a cost effective solution for meeting the broad range of functional requirements.


2018 ◽  
Vol 35 (9) ◽  
pp. 1256-1260 ◽  
Author(s):  
Jeffrey Wang ◽  
Shahida Khan ◽  
Paige Wyer ◽  
Jessica Vanderwilp ◽  
Justin Reynolds ◽  
...  

Background: Patients with ascites suffer from distressing symptoms and are at high risk for readmission after hospitalization. Timely paracentesis is an important palliative tool in managing this vulnerable population. At our institution, we have developed a multidisciplinary transitional care program for patients discharged from the hospital with a wide range of complex conditions including refractory ascites. Methods: We present a case series of 10 patients with symptomatic ascites who were enrolled in our transitional care program and treated with ultrasound-guided therapeutic paracentesis in our clinic. Patient medical records were retrospectively reviewed to collect procedure details, outcomes, and follow-up data on emergency department (ED) visits and readmissions. Cost data were obtained from the hospital financial system. Results: Over the span of 9 months (September 2016 to July 2017), 22 total therapeutic paracenteses were performed on 10 unique patients in the transitional care clinic. Median age of the patient cohort was 52.5 years (range: 27-71 years). All patients reported immediate relief of ascites-related discomfort following the procedure. We did not observe any major adverse effects due to the in-clinic procedure. Nine of the 10 patients did not have any ED visits or readmissions within 30 days of discharge. The cost of performing ultrasound-guided paracentesis in the transitional care clinic was US$546.77 compared to US$978.32 when performed in the hospital. Conclusion: Our experience suggests that outpatient paracentesis may be a safe, feasible, and cost-effective means of providing symptom management for patients with ascites during their transition from hospital to home.


PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254097
Author(s):  
Chase S. Jalbert ◽  
Jeffrey A. Falke ◽  
J. Andrés López ◽  
Kristine J. Dunker ◽  
Adam J. Sepulveda ◽  
...  

The relentless role of invasive species in the extinction of native biota requires predictions of ecosystem vulnerability to inform proactive management strategies. The worldwide invasion and range expansion of predatory northern pike (Esox lucius) has been linked to the decline of native fishes and tools are needed to predict the vulnerability of habitats to invasion over broad geographic scales. To address this need, we coupled an intrinsic potential habitat modelling approach with a Bayesian network to evaluate the vulnerability of five culturally and economically vital species of Pacific salmon (Oncorhynchus spp.) to invasion by northern pike. This study was conducted along 22,875 stream km in the Southcentral region of Alaska, USA. Pink salmon (O. gorbuscha) were the most vulnerable species, with 15.2% (2,458 km) of their calculated extent identified as “highly” vulnerable, followed closely by chum salmon (O. keta, 14.8%; 2,557 km) and coho salmon (O. kisutch, 14.7%; 2,536 km). Moreover, all five Pacific salmon species were highly vulnerable in 1,001 stream km of shared habitat. This simple to implement, adaptable, and cost-effective framework will allow prioritizing habitats for early detection and monitoring of invading northern pike.


2010 ◽  
Vol 44 (2) ◽  
pp. 56-63 ◽  
Author(s):  
Kris I. Waddington ◽  
Ben W. Piek ◽  
Antony D. Payne ◽  
Simon L. Grove ◽  
Euan S. Harvey ◽  
...  

AbstractQuantitative sampling of benthic communities is central to a wide range of ecological research, from understanding spatial distribution and ecology to impact studies. With the need to sample deep as well as shallow regions, limited sampling capabilities of diver-based methods and the expanding footprint of human activity, there is a need for an effective system capable of classifying benthic assemblages and able to monitor potential anthropogenic impacts. Here we describe a remote system capable of collecting benthic photo-quadrats to depths of 100 m. A procedure for the classification of these images into 64 abiotic and biotic categories is also described. During a 64-day sampling program that included sampling at seven locations along 1,200 km of coastline that resulted in the collection of over 9,000 images, only one day of sampling was lost due to equipment malfunction, with 99.5% of points able to be classified to the taxonomic resolution required, demonstrating the reliability and accuracy of this system. Furthermore, the incorporation of differential GPS and ultra-short baseline positioning system allowed collected images to be geo-referenced to within 0.5 m. Such precision allows the system to be used in conjunction with hydroacoustic habitat mapping techniques and potentially for repeated monitoring of areas with a small spatial extent. Development of this system provides a cost-effective means of quantifying benthic assemblages over broad scales.


2020 ◽  
Vol 6 (3) ◽  
pp. 51-57
Author(s):  
Roman A. Khmel’nitskij ◽  
Аndrej V. Vislobokov

Introduction: Given a wide range of pathogenesis of the inflammatory process in pyoderma, which involves a variety of links in the immune response, work is underway to find ways to optimize immunocorrection in this pathology. The aim of the study was to evaluate the clinical and economic effectiveness of immunocorrection in severe and chronic forms of pyoderma with drugs from different pharmacological groups. Materials and methods: The data sources were prospective randomized comparative studies of therapy of 107 pyoderma patients aged 18 to 60 years, divided into groups. The patients of the first group additionally used a biologically active additive containing immunoactive molecules and transfer factors (TF) as an immunomodulator; the patients of the second group used glucosaminylmuramildipeptide (GMDP). The clinical effectiveness of regression of inflammatory symptoms on day 10 of treatment was analyzed. Based on the obtained data, the following types of pharmacoeconomical analysis were performed: calculation of the course price, the cost/effectiveness ratio, and the availability coefficient. Results and discussion: The results of the study showed that the number of cured patients was 91.4% in the first group and 97.2% in the second group of patients. The treatment cost when using the drug is by 970 rubles smaller; the cost/effectiveness ratio (CER) per patient was 1.8 higher for a drug containing transfer factors and amounted to 25.9. The calculation of the availability coefficient (AC) revealed a difference in glucosaminylmuramyldipeptide which was 2.1 times smaller. Conclusion: It was found that a drug based on glucosaminylmuramildipeptide is a more effective and cost-effective means of immunocorrection in severe forms of pyoderma. This confirms a faster regression of clinical manifestations of the disease and lower cost/effectiveness ratio and availability coefficient.


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