scholarly journals Using river temperature to optimize fish incubation metabolism and survival: a case for mechanistic models

2018 ◽  
Author(s):  
James J. Anderson
Keyword(s):  
Chinook Salmon ◽  
Survival Data ◽  
Reservoir Operations ◽  
River Temperature ◽  
Growth And Survival ◽  
The Past ◽  
Density Dependent Mortality ◽  
Resource Managers ◽  
Organism Growth ◽  
New Strategies

AbstractAllocating reservoir flows to societal and ecosystem needs under increasing demands for water and increasing variability in climate presents challenges to resource managers. In the past, managers have operated reservoirs to achieve flow and temperature compliance points based on qualitative predictions of competing needs. Because it is difficult, if not impossible, to assess whether meeting such compliance points is efficient or equitable, new strategies for regulation are being advanced. Critical to these strategies is the need for new models with sufficient biological details to identify the effects of reservoir operations on organism growth and survival in real time. This paper evaluates the adequacy of three models of differing complexity for managing the Sacramento River temperature during the incubation of winter-run Chinook salmon. The models similarly characterize temperature-and density-dependent mortality from egg through fry survival, but use different spatial and temporal resolutions. The models all fit survival data reasonably well, but predict different reservoir operations to protect fish. Importantly, the models with the finer spatial/temporal resolution predict reservoir operations that require less flow and better protect fish when water resources are limited. The paper illustrates that shifting the focus of management from meeting compliance points to meeting the metabolic needs of the organisms’ yields efficiencies and identifies when water is needed and when it can be saved.

Acoustically derived fine-scale behaviors of juvenile Chinook salmon (Oncorhynchus tshawytscha) associated with intertidal benthic habitats in an estuary

2008 ◽  
Vol 65 (9) ◽  
pp. 2053-2062 ◽  
Author(s):  
Brice Xavier Semmens
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
State Space Model ◽  
Benthic Habitat ◽  
Zostera Japonica ◽  
Willapa Bay ◽  
Benthic Habitats ◽  
Growth And Survival ◽  
Resource Managers ◽  
Behavioral Preference

Given the presumed importance of benthic and epibenthic estuarine habitats in Chinook salmon ( Oncorhynchus tshawytscha ) smolt growth and survival, resource managers would be well served by an improved understanding of how smolts use such habitats. A cabled acoustic positioning system was used to precisely track (<1 m resolution) the movement of seventeen 0-aged hatchery-reared fall Chinook smolts in a large (~4000 m2) enclosure over a period of 10 days in Willapa Bay, Washington, USA. A hierarchical Bayesian state–space model of movement was subsequently developed to associate the behaviors of tagged salmon with characteristics of benthic habitat in the enclosure. Model results indicated that smolts had a strong preference for remaining in native eelgrass ( Zostera marina ). Conversely, no such preference existed for other structured benthic habitats such as oyster ( Crassostrea gigas ) beds, non-native eelgrass ( Zostera japonica ), and non-native smooth cordgrass ( Spartina alterniflora ). There was a positive relationship between individual survivorship in the enclosure and the strength of behavioral preference for native eelgrass, suggesting that predator avoidance may be the evolutionary mechanism driving behavioral responses of smolts to benthic habitats.

scholarly journals Mesenchymal stem cells and oncolytic viruses: joining forces against cancer

2021 ◽  
Vol 9 (2) ◽  
pp. e001684
Author(s):  
Rafael Moreno
Keyword(s):  
Stem Cells ◽  
Clinical Trials ◽  
Mesenchymal Stem Cells ◽  
Immune System ◽  
Oncolytic Viruses ◽  
Immunogenic Cell Death ◽  
The Past ◽  
Physical Barriers ◽  
Immunogenic Properties ◽  
New Strategies

The development of oncolytic viruses (OVs) has increased significantly in the past 20 years, with many candidates entering clinical trials and three of them receiving approval for some indications. Recently, OVs have also gathered interest as candidates to use in combination with immunotherapies for cancer due to their immunogenic properties, which include immunogenic cell death and the possibility to carry therapeutic transgenes in their genomes. OVs transform non-immunogenic ‘cold’ tumors into inflamed immunogenic ‘hot’ tumors, where immunotherapies show the highest efficacy. However, in monotherapy or in combination with immunotherapy, OVs face numerous challenges that limit their successful application, in particular upon systemic administration, such as liver sequestration, neutralizing interactions in blood, physical barriers to infection, and fast clearance by the immune system. In this regard, the use of mesenchymal stem cells (MSCs) as cells carrier for OV delivery addresses many of these obstacles acting as virus carriers and factories, expressing additional transgenes, and modulating the immune system. Here, I review the current progress of OVs-loaded MSCs in cancer, focusing on their interaction with the immune system, and discuss new strategies to improve their therapeutic efficacy.

Quantifying the threat to archaeological sites from the erosion of cultivated soil

Antiquity ◽  
2006 ◽  
Vol 80 (309) ◽  
pp. 658-670 ◽  
Author(s):  
Keith Wilkinson ◽  
Andrew Tyler ◽  
Donald Davidson ◽  
Ian Grieve
Keyword(s):  
World Wide ◽  
Site Formation ◽  
Archaeological Sites ◽  
Site Formation Processes ◽  
Formation Processes ◽  
Know How ◽  
The Past ◽  
Nuclear Weapons Testing ◽  
Resource Managers ◽  
Soil Movements

Ploughing is probably the greatest agent of attrition to archaeological sites world-wide. In every country, every year, a bit more is shaved off buried strata and a bit more of the past becomes unreadable. On the other hand, people must eat and crops must be planted. How can the fields be best managed to get the best of both worlds? Perhaps the most pressing need for resource managers is to know how quickly a particular field is eroding: negotiation and protection is then possible. Up to now that has been difficult to measure.The new procedure presented here, which draws on the unexpected benefits of nuclear weapons testing, shows how variation in the concentration of the radioisotope 137Cs can be used to monitor soil movements over the last 40 years. The measurements allow a site's ‘life expectancy’ to be calculated, and there are some promising dividends for tracking site formation processes.

Egyptology and Global History: Between Geocultural Power and the Crisis of Humanities

2021 ◽  
Vol 13 (1-2) ◽  
pp. 29-76
Author(s):  
Juan Carlos Moreno García
Keyword(s):  
Social Sciences ◽  
Global History ◽  
Historical Perspectives ◽  
The Past ◽  
Gradual Loss ◽  
Dynamic Flows ◽  
Western Hegemony ◽  
Intellectual Environment ◽  
New Strategies ◽  
New Framework

Abstract Globalization, the decline of Western hegemony, and the rise of new political and economic actors, particularly in East Asia, are concomitant with the emergence of more encompassing historical perspectives, attentive to the achievements and historical trajectories of other regions of the world. Global history provides thus a new framework to understanding our past that challenges former views based on the cultural needs, values, and expectations of the West. This means that humanities and social sciences are subject to intense scrutiny and pressed to adapt themselves to a changing cultural, academic, and intellectual environment. However, this process is hindered by the gradual loss of their former prestige and by the increasing influence of economics in the reorganization of the educational, research, and cultural agenda according to market-oriented criteria. The result is that the mobilization of the past increasingly conforms to new strategies in which connectivity, trading, and diplomatic interests, as well as integration in dynamic flows of wealth, appear of paramount importance. Egyptology is not alien to these challenges, which will in all probability reshape its very foundations in the foreseeable future.

scholarly journals Process-based model of fish incubation survival for designing reservoir operations: a case study for Sacramento River winter-run Chinook salmon

2020 ◽  
Author(s):  
James J. Anderson ◽  
W. Nicholas Beer ◽  
Joshua A. Israel ◽  
Sheila Greene
Keyword(s):  
Real Time ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Cold Water ◽  
Climatic Variability ◽  
Sacramento River ◽  
Reservoir Operations ◽  
Regulated Rivers ◽  
Egg Hatching ◽  
Critical Window

AbstractAllocating reservoir flows to meet societal and ecosystem needs under increasing demands for water and increasing climatic variability presents challenges to resource managers. Often, regulated rivers have been operated to meet flow and temperature compliance points that mimic historical patterns. Because it is difficult to assess if this approach is efficient or equitable, new more process-based approaches to regulation are being advanced. This paper describes such an approach with a model of egg incubation survival of Sacramento River winter-run Chinook salmon (SRWRC, Oncorhynchus tshawytscha). Thermal mortality only occurs in a critical window around egg hatching when the embryo is most sensitive to temperature stress. The duration of the critical window has significant implications for Shasta Reservoir operations that are designed to control temperature during SRWRC incubation. Previous operations sought to maintain a low temperature over the entire incubation period. However, model analysis suggests that targeting cold water directly to the critical egg hatching stage provides higher survival while requiring less cold water resources. The calibrated model is publicly accessible through a web interface connected to real-time river and fish databases and a river temperature forecast model. The system is an example of the next step of river management that integrates databases with hydrological and process-based biological models for real-time analysis and for forecasting effects of river operations on the environment.

An Evaluation of Rearing Densities to Improve Growth and Survival of Hatchery Spring Chinook Salmon

2013 ◽  
Vol 4 (1) ◽  
pp. 114-123 ◽  
Author(s):  
Douglas E. Olson ◽  
Michael Paiya
Keyword(s):  
Mortality Rate ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Confounding Factor ◽  
Fork Length ◽  
High Density ◽  
Growth And Survival ◽  
Migration Timing ◽  
Rearing Density ◽  
Salmon Stock

Abstract We evaluated growth and survival of spring Chinook salmon Oncorhynchus tshawytscha reared at varying densities at Warm Springs National Fish Hatchery, Oregon. For three consecutive brood years, density treatments consisted of low, medium, and high groups in 57.8-m3 raceways with approximately 16,000, 24,000, and 32,000 fish/raceway, respectively. Fish were volitionally released in both the autumn and spring to mimic the downstream migration timing of the endemic wild spring Chinook salmon stock. Just prior to the autumn release, the rearing density estimate was 4.24 kg/m3 for the low-density group, 6.27 kg/m3 for the medium-density group, and 8.42 kg/m3 for the high-density group. While weight gain did not differ among density treatments (P  =  0.72), significant differences were found in median fork length (P &lt; 0.001) for fish reared at different densities. Fish reared at high density exhibited the highest on-hatchery mortality rate during two brood years; however, differences in mortality rate among densities were not significant (P  =  0.20). In one brood year, adult recovery rates appeared to support the hypothesis that lower initial densities improved postrelease survival (P &lt; 0.01). All rearing densities utilized in this evaluation were relatively low and may partially explain why more differences were not readily apparent among density groups. In addition, the volitional release was a confounding factor in our study because we were unable to quantify the number of fish released in the autumn.

scholarly journals Costs and Returns of Fishermen in the Massachusetts Inshore Lobster Fishery

1975 ◽  
Vol 4 (2) ◽  
pp. 195-210 ◽  
Author(s):  
J. M. Gates ◽  
J. M. D'Eugenio
Keyword(s):  
Fisheries Management ◽  
Fishing Effort ◽  
The State ◽  
Economic Factors ◽  
Sufficient Criterion ◽  
Fish Stocks ◽  
The Past ◽  
Resource Managers ◽  
Lobster Fishery

The inshore lobster fishery is one of the more important ones in the Commonwealth of Massachusetts, accounting for approximately 14 percent of the total landed value of all species in Massachusetts in 1971. Until recent years this fishery accounted for virtually all the pot landings in the state. Despite numerous attempts at conservation such as gear regulation, size restrictions, and prohibitions on harvesting egg-bearing females, the fishery has been subject to rapidly increasing effort and virtually constant landings. In the past decade it has become obvious to many fishery biologists and economists that conservation of fish stocks is a necessary but not sufficient criterion for fisheries management. Resource managers have become increasingly aware of the interdependence between economic factors and the intensity, location and composition of fishing effort.

scholarly journals Evolving impact of long-term survival results on metastatic melanoma treatment

2020 ◽  
Vol 8 (2) ◽  
pp. e000948 ◽  
Author(s):  
Olivier Michielin ◽  
Michael B Atkins ◽  
Henry B Koon ◽  
Reinhard Dummer ◽  
Paolo Antonio Ascierto
Keyword(s):  
Targeted Therapies ◽  
Survival Data ◽  
Long Term Results ◽  
Tumor Type ◽  
Term Survival ◽  
Long Term Survival ◽  
The Past ◽  
Number Of Patients ◽  
Melanoma Treatment

Melanoma treatment has been revolutionized over the past decade. Long-term results with immuno-oncology (I-O) agents and targeted therapies are providing evidence of durable survival for a substantial number of patients. These results have prompted consideration of how best to define long-term benefit and cure. Now more than ever, oncologists should be aware of the long-term outcomes demonstrated with these newer agents and their relevance to treatment decision-making. As the first tumor type for which I-O agents were approved, melanoma has served as a model for other diseases. Accordingly, discussions regarding the value and impact of long-term survival data in patients with melanoma may be relevant in the future to other tumor types. Current findings indicate that, depending on the treatment, over 50% of patients with melanoma may gain durable survival benefit. The best survival outcomes are generally observed in patients with favorable prognostic factors, particularly normal baseline lactate dehydrogenase and/or a low volume of disease. Survival curves from melanoma clinical studies show a plateau at 3 to 4 years, suggesting that patients who are alive at the 3-year landmark (especially in cases in which treatment had been stopped) will likely experience prolonged cancer remission. Quality-of-life and mixture-cure modeling data, as well as metrics such as treatment-free survival, are helping to define the value of this long-term survival. In this review, we describe the current treatment landscape for melanoma and discuss the long-term survival data with immunotherapies and targeted therapies, discussing how to best evaluate the value of long-term survival. We propose that some patients might be considered functionally cured if they have responded to treatment and remained treatment-free for at least 2 years without disease progression. Finally, we consider that, while there have been major advances in the treatment of melanoma in the past decade, there remains a need to improve outcomes for the patients with melanoma who do not experience durable survival.

Development, Growth, and Survival of Lepeophtheirus Salmonis (Copepoda: Caligidae) Under Laboratory Conditions

1991 ◽  
Vol 71 (2) ◽  
pp. 425-436 ◽  
Author(s):  
S. C. Johnson ◽  
L. J. Albright
Keyword(s):  
Adult Female ◽  
Survival Data ◽  
Laboratory Experiments ◽  
Development Time ◽  
Lepeophtheirus Salmonis ◽  
Survival Times ◽  
Growth And Survival ◽  
Average Survival ◽  
Copepodid Stage ◽  
The Mean

Development, growth, and survival data derived from laboratory experiments are provided for Lepeophtheirus salmonis, a common ectoparasite of wild and sea-farmed salmonids. The mean development time of eggs was 419·1 hours (17·5 days) at 5°C, 207·1 hours (8·6 days) at 10°C, and 130·8 hours (5·5 days) at 15°C. Development from the first nauplius to the infectious copepodid stage took 222·3 hours (9·3 days) at 5°C, 87·4 hours (3·6 days) at 10°C, and 44·8 (1·9 days) hours at 15°C. Development from the egg to the adult male took 40 days, and from the egg to the adult female 52 days at 10°C. No egg development occurred at 10‰ salinity. At 15‰ eggs developed but failed to produce active nauplii. At higher salinities (20–3‰) active nauplii were produced, but copepodids were only obtained at 30‰. Copepodids survived for less than 1 day in waters with a salinity of 10‰ or less. At higher salinities (15–30‰) and temperatures of 5,10, and 15°C average survival times ranged between 2 and 8 days.

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