scholarly journals The mechanics of predator-prey interactions: first principles of physics predict predator-prey size ratios

2018 ◽  
Author(s):  
Sébastien M. J. Portalier ◽  
Gregor F. Fussmann ◽  
Michel Loreau ◽  
Mehdi Cherif
Keyword(s):  
Food Webs ◽  
Net Energy ◽  
List Type ◽  
Model Accuracy ◽  
Predator Prey ◽  
Physical Constraints ◽  
Prey Interaction ◽  
Body Sizes ◽  
Net Energy Gain

AbstractRobust predictions of predator-prey interactions are fundamental for the understanding of food webs, their structure, dynamics, resistance to species loss and invasions and role in ecosystem functioning. Most current food web models are empirically based. Thus, they are sensitive to the quality of the data, and ineffective in predicting non-described and disturbed food webs. There is a need for mechanistic models that predict the occurrence of a predator-prey interaction based on the traits of organisms and the properties of their environment.Here, we present such a model that focuses on the predation act itself. We built a Newtonian, mechanical model for the processes of searching, capture and handling of a prey item by a predator. Associated with general metabolic laws, we predict the net energy gain from predation for pairs of predator and prey species depending on their body sizes.Predicted interactions match well with data from the most extensive predator-prey database, and overall model accuracy is greater than the niche model.Our model shows that it is possible to accurately predict the structure of food webs using only a few ecomechanical traits. It underlines the importance of physical constraints in structuring food webs.

scholarly journals Decomposing the effects of ocean environments on predator–prey body-size relationships in food webs

2018 ◽  
Vol 5 (7) ◽  
pp. 180707 ◽  
Author(s):  
Tomoya Dobashi ◽  
Midori Iida ◽  
Kazuhiro Takemoto
Keyword(s):  
Body Size ◽  
Food Webs ◽  
Oxygen Concentration ◽  
Large Scale ◽  
Small Body ◽  
Large Body ◽  
Predator Prey ◽  
Body Sizes ◽  
And Function ◽  
The Impact

Body-size relationships between predators and their prey are important in ecological studies because they reflect the structure and function of food webs. Inspired by studies on the impact of global warming on food webs, the effects of temperature on body-size relationships have been widely investigated; however, the impact of environmental factors on body-size relationships has not been fully evaluated because climate warming affects various ocean environments. Thus, here, we comprehensively investigated the effects of ocean environments and predator–prey body-size relationships by integrating a large-scale dataset of predator–prey body-size relationships in marine food webs with global oceanographic data. We showed that various oceanographic parameters influence prey size selection. In particular, oxygen concentration, primary production and salinity, in addition to temperature, significantly alter body-size relationships. Furthermore, we demonstrated that variability (seasonality) of ocean environments significantly affects body-size relationships. The effects of ocean environments on body-size relationships were generally remarkable for small body sizes, but were also significant for large body sizes and were relatively weak for intermediate body sizes, in the cases of temperature seasonality, oxygen concentration and salinity variability. These findings break down the complex effects of ocean environments on body-size relationships, advancing our understanding of how ocean environments influence the structure and functioning of food webs.

scholarly journals Modelling Exposure by Spraying Activities—Status and Future Needs

2021 ◽  
Vol 18 (15) ◽  
pp. 7737
Author(s):  
Stefan Hahn ◽  
Jessica Meyer ◽  
Michael Roitzsch ◽  
Christiaan Delmaar ◽  
Wolfgang Koch ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Model Performance ◽  
Relevant Information ◽  
Systematic Evaluation ◽  
Model Accuracy ◽  
Efficient Manner ◽  
User Perspective ◽  
Model Predictions ◽  
Spray Applications

Spray applications enable a uniform distribution of substances on surfaces in a highly efficient manner, and thus can be found at workplaces as well as in consumer environments. A systematic literature review on modelling exposure by spraying activities has been conducted and status and further needs have been discussed with experts at a symposium. This review summarizes the current knowledge about models and their level of conservatism and accuracy. We found that extraction of relevant information on model performance for spraying from published studies and interpretation of model accuracy proved to be challenging, as the studies often accounted for only a small part of potential spray applications. To achieve a better quality of exposure estimates in the future, more systematic evaluation of models is beneficial, taking into account a representative variety of spray equipment and application patterns. Model predictions could be improved by more accurate consideration of variation in spray equipment. Inter-model harmonization with regard to spray input parameters and appropriate grouping of spray exposure situations is recommended. From a user perspective, a platform or database with information on different spraying equipment and techniques and agreed standard parameters for specific spraying scenarios from different regulations may be useful.

Law for Aerospace Activities 1966-2066

1969 ◽  
Vol 73 (700) ◽  
pp. 255-270
Author(s):  
H. Caplan
Keyword(s):  
The Other ◽  
List Type ◽  
Type Number ◽  
The Future ◽  
Impossible Task

The purpose of this prologue is to outline how I have approached the arrogant and impossible task of surveying an unborn century of law. I may also be able to illustrate that the nature and quality of the task is completely different from that attempted in the preceding papers. In the whole paper I have done little more than infer repeatedly, in different ways (a) that the shape of the future so far as law is concerned will be determined by the methods of communication adopted between sectors of the aerospace community and between the aerospace community and society at large, and (b) that the search for effective methods of communication is urgent. But my target is not the lawyers of our community—who I am not qualified to advise. I write for the other members of the Royal Aeronautical Society and I return to the task of persuading them that they have a role to play in evolving future laws for aerospace activities.

scholarly journals Do we have enough information to apply the ecosystem approach to management of deep-sea fisheries? An example from the West of Scotland

2010 ◽  
Vol 68 (2) ◽  
pp. 265-280 ◽  
Author(s):  
Johanna J. Heymans ◽  
Kerry L. Howell ◽  
Morag Ayers ◽  
Michael T. Burrows ◽  
John D. M. Gordon ◽  
...  
Keyword(s):  
Deep Sea ◽  
Ecosystem Model ◽  
Ecosystem Approach ◽  
The West ◽  
Holistic View ◽  
Predator Prey ◽  
Relative Paucity ◽  
Water Ecosystem ◽  
Fisheries Interactions

Abstract Heymans, J. J., Howell, K. L., Ayers, M., Burrows, M. T., Gordon, J. D. M., Jones, E. G., and Neat, F. 2011. Do we have enough information to apply the ecosystem approach to management of deep-sea fisheries? An example from the West of Scotland. – ICES Journal of Marine Science, 68: 265–280. There is currently a global call for more use of an ecosystem approach to fisheries management (EAFM), and ecosystem models such as Ecopath with Ecosim (EwE) are being used to provide a holistic view of ecosystem–fisheries interactions. Although these can be useful for an EAFM, the relative paucity of data available for deep-sea ecosystems raises concerns whether we can effectively apply an EAFM to the deep sea. The deep-sea ecosystem off the west coast of Scotland has been studied for longer and in more detail than most. This study assimilates the significant published and unpublished information available on this ecosystem into an EwE model. The results suggest that there are sufficient data available to construct an ecosystem model, but the quality of the data varies and serious potential sources of error are present in biomass and discard estimates. The assumptions needed to produce a model are varied and must be considered when interpreting the outputs of the model. Ecosystem modelling provides a unique view of the deep-water ecosystem and facilitates hypothesis development concerning predator–prey and inter-fishery interactions. Sharks are used to illustrate the benefits of using an ecosystem model to describe changes in their biomass and their prey species. The results show that both fishing for sharks and fishing for their prey affect the biomass of sharks.

scholarly journals Predator-prey Interaction between a Ciliated Protozoan Trochilioides recta and Filamentous Bacteria

1989 ◽  
Vol 12 (4) ◽  
pp. 239-245,231 ◽  
Author(s):  
Minako KOGA ◽  
Takeshi SEGUCHI ◽  
Tadahiro MORI ◽  
Yuhei INAMORI ◽  
Ryuichi SUDO
Keyword(s):  
Filamentous Bacteria ◽  
Ciliated Protozoan ◽  
Predator Prey ◽  
Prey Interaction

Identifikasi Faktor-faktor yang Memengaruhi Hasil Akreditasi SMA di Indonesia Berdasarkan Data ARKAS

2021 ◽  
Vol 10 (3) ◽  
pp. 258-269
Author(s):  
Muh Nur Fiqri Adham ◽  
Budi Susetyo ◽  
Kusman Sadik ◽  
Satriyo Wibowo
Keyword(s):  
High School ◽  
Study Groups ◽  
Quality Of Education ◽  
Ministry Of Education ◽  
Model Accuracy ◽  
National Education ◽  
Explanatory Variables ◽  
School Budget ◽  
Ordinal Logistic Regression Analysis

Accreditation is an indicator of the quality of education at the education unit level. One affects the quality of education units is the school budget. School budgets are prepared in order to fulfill 8 national education standards. School budget management uses School Activity Plan and Budget Application (ARKAS) developed by the Ministry of Education, Culture, Research and Technology (Kemendikbudristek). ARKAS is an information system for managing school budget and expenditure planning. The Research is identifies the factors that influence the accreditation of high school (SMA) with accreditation as a response variable and 17 explanatory variables sourced from ARKAS and Dapodik data using ordinal logistic regression analysis. The best model stage is the model formed that has the smallest AIC value and has high model accuracy in determining the best model. The best model stage is the third model stage which is composed of 7 explanatory variables that affect the high school accreditation rating with AIC value of 1886,20 and model accuracy of 65,79%. The variables that affect to results of accreditation include school status, percentage of students eligible PIP, ratio of the number of students per number of teachers, percentage of teachers certified educators, ratio of the number of students per number of study groups, ratio of the number of students per number of computers, and ratio of the number of students per number of toilets

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