POPULATION MORTALITY AND CYCLICITY AS AFFECTED BY INTRASPECIFIC COMPETITION,

1977 ◽  
Vol 109 (6) ◽  
pp. 879-890 ◽  
Author(s):  
R. E. Stinner ◽  
J. W. Jones ◽  
C. Tuttle ◽  
R. E. Caron
Keyword(s):  
Probability Theory ◽  
Spatial Distribution ◽  
Intraspecific Competition ◽  
Heliothis Zea ◽  
Survival Rates ◽  
Basic Probability ◽  
Simulation Results ◽  
Population Mortality

AbstractA model for intraspecific competition that incorporates the effects of inter- and intra-stage survival rates, spatial distribution, and variation in growth is developed using basic probability theory. Simulation results for cannibalism in Heliothis zea (Boddie) are presented and intraspecific competition is shown to have effects on population cyclicity and on mortality.

scholarly journals On Basic Probability Logic Inequalities

Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1409
Author(s):  
Marija Boričić Joksimović
Keyword(s):  
Probability Theory ◽  
Inference Rule ◽  
Modus Ponens ◽  
Probability Logic ◽  
Modus Tollens ◽  
Short Overview ◽  
Basic Probability ◽  
Probabilistic Version ◽  
Hypothetical Syllogism

We give some simple examples of applying some of the well-known elementary probability theory inequalities and properties in the field of logical argumentation. A probabilistic version of the hypothetical syllogism inference rule is as follows: if propositions A, B, C, A→B, and B→C have probabilities a, b, c, r, and s, respectively, then for probability p of A→C, we have f(a,b,c,r,s)≤p≤g(a,b,c,r,s), for some functions f and g of given parameters. In this paper, after a short overview of known rules related to conjunction and disjunction, we proposed some probabilized forms of the hypothetical syllogism inference rule, with the best possible bounds for the probability of conclusion, covering simultaneously the probabilistic versions of both modus ponens and modus tollens rules, as already considered by Suppes, Hailperin, and Wagner.

Basic probability theory

1992 ◽  
pp. 21-53
Author(s):  
Roy Billinton ◽  
Ronald N. Allan
Keyword(s):  
Probability Theory ◽  
Basic Probability

scholarly journals How can expert knowledge increase the realism of conceptual hydrological models? A case study based on the concept of dominant runoff process in the Swiss Pre-Alps

2018 ◽  
Vol 22 (8) ◽  
pp. 4425-4447 ◽  
Author(s):  
Manuel Antonetti ◽  
Massimiliano Zappa
Keyword(s):  
Spatial Distribution ◽  
Expert Knowledge ◽  
Hydrological Models ◽  
Top Down ◽  
Bottom Up ◽  
Process Maps ◽  
Uncertainty Sources ◽  
Simulation Results ◽  
Set Up ◽  
Better Than

Abstract. Both modellers and experimentalists agree that using expert knowledge can improve the realism of conceptual hydrological models. However, their use of expert knowledge differs for each step in the modelling procedure, which involves hydrologically mapping the dominant runoff processes (DRPs) occurring on a given catchment, parameterising these processes within a model, and allocating its parameters. Modellers generally use very simplified mapping approaches, applying their knowledge in constraining the model by defining parameter and process relational rules. In contrast, experimentalists usually prefer to invest all their detailed and qualitative knowledge about processes in obtaining as realistic spatial distribution of DRPs as possible, and in defining narrow value ranges for each model parameter.Runoff simulations are affected by equifinality and numerous other uncertainty sources, which challenge the assumption that the more expert knowledge is used, the better will be the results obtained. To test for the extent to which expert knowledge can improve simulation results under uncertainty, we therefore applied a total of 60 modelling chain combinations forced by five rainfall datasets of increasing accuracy to four nested catchments in the Swiss Pre-Alps. These datasets include hourly precipitation data from automatic stations interpolated with Thiessen polygons and with the inverse distance weighting (IDW) method, as well as different spatial aggregations of Combiprecip, a combination between ground measurements and radar quantitative estimations of precipitation. To map the spatial distribution of the DRPs, three mapping approaches with different levels of involvement of expert knowledge were used to derive so-called process maps. Finally, both a typical modellers' top-down set-up relying on parameter and process constraints and an experimentalists' set-up based on bottom-up thinking and on field expertise were implemented using a newly developed process-based runoff generation module (RGM-PRO). To quantify the uncertainty originating from forcing data, process maps, model parameterisation, and parameter allocation strategy, an analysis of variance (ANOVA) was performed.The simulation results showed that (i) the modelling chains based on the most complex process maps performed slightly better than those based on less expert knowledge; (ii) the bottom-up set-up performed better than the top-down one when simulating short-duration events, but similarly to the top-down set-up when simulating long-duration events; (iii) the differences in performance arising from the different forcing data were due to compensation effects; and (iv) the bottom-up set-up can help identify uncertainty sources, but is prone to overconfidence problems, whereas the top-down set-up seems to accommodate uncertainties in the input data best. Overall, modellers' and experimentalists' concept of model realism differ. This means that the level of detail a model should have to accurately reproduce the DRPs expected must be agreed in advance.

Computation of Madalines' Sensitivity to Input and Weight Perturbations

2006 ◽  
Vol 18 (11) ◽  
pp. 2854-2877 ◽  
Author(s):  
Yingfeng Wang ◽  
Xiaoqin Zeng ◽  
Daniel So Yeung ◽  
Zhihang Peng
Keyword(s):  
Probability Theory ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
Analytical Formula ◽  
Single Neurons ◽  
Important Measure ◽  
Simulation Results ◽  
Theoretical Results ◽  
Good Agreement

The sensitivity of a neural network's output to its input and weight perturbations is an important measure for evaluating the network's performance. In this letter, we propose an approach to quantify the sensitivity of Madalines. The sensitivity is defined as the probability of output deviation due to input and weight perturbations with respect to overall input patterns. Based on the structural characteristics of Madalines, a bottomup strategy is followed, along which the sensitivity of single neurons, that is, Adalines, is considered first and then the sensitivity of the entire Madaline network. Bymeans of probability theory, an analytical formula is derived for the calculation of Adalines' sensitivity, and an algorithm is designed for the computation of Madalines' sensitivity. Computer simulations are run to verify the effectiveness of the formula and algorithm. The simulation results are in good agreement with the theoretical results.

Spatial distribution and seed mass variation of Strophostyles helvola along Lake Erie

1996 ◽  
Vol 74 (8) ◽  
pp. 1313-1321 ◽  
Author(s):  
Mary Yanful ◽  
M. A. Maun
Keyword(s):  
Spatial Distribution ◽  
Intraspecific Competition ◽  
Lake Erie ◽  
Seed Mass ◽  
Field Studies ◽  
Sandy Beaches ◽  
Recurrent Event ◽  
Limiting Factor ◽  
Probability Of Survival ◽  
The Waves

Field studies were conducted to determine the survival, seed-mass variability, and reproductive strategies of wild bean, Strophostyles helvola (L.) Ell., plants on the foredunes at Port Burwell Provincial Park along Lake Erie. In spring, a large number of seedlings were found on the drift-line (area of beach where detritis deposits are cast on shore by the waves) and a small number both on the lakeward (mid-beach) and landward (high-beach) ends of the drift-line. Plants growing on the mid-beach were larger and produced a significantly greater number of heavier seeds than those on the drift-line. However, during late fall and winter months, a large proportion of these seeds were moved by wind and wave action to the drift-line. Intraspecific competition was not a limiting factor on the mid-beach; however, on the drift-line, the number of seeds per plant decreased significantly with an increase in density of plants from about 1 to 140/m2, suggesting that intraspecific competition may be an important limiting factor in seed production per plant. The mean mass per seed significantly declined over the growing season of S. helvola. There was a significant increase in mean seed mass with increasing pod size. Seeds in the centre of a pod were significantly heavier than those at the proximal and distal ends of a pod. Strophostyles helvola is able to flourish in the constantly shifting shoreline beach habitats along Lake Erie owing to two main factors. First, it is able to fully utilize the highly variable beach microhabitats and maintain high total reproductive output per square metre. Second, since burial in sand is a major recurrent event on sandy beaches, the high variability in seed mass will be of adaptive significance because seedlings from large seeds will not only be able to emerge from greater depths of burial in sand but also will have greater probability of survival under burial conditions. Keywords: seed mass, plant location, Strophostyles helvola, seed position, spatial distribution.

Experimental analysis of intraspecific composition in an intertidal gastropod, Littorina unifasciata

1981 ◽  
Vol 32 (4) ◽  
pp. 573 ◽  
Author(s):  
GM Branch ◽  
ML Branch
Keyword(s):  
Food Availability ◽  
Intraspecific Competition ◽  
Field Experiments ◽  
Small Body ◽  
Standing Stock ◽  
Rocky Shores ◽  
Physiological Tolerance ◽  
South Wales ◽  
Body Sizes ◽  
Population Mortality

L. unifasciata dominates the upper levels of rocky shores at Cape Banks, New South Wales. Peak densities of up to 9600 m-2 occur near the centre of the littorine's vertical zonation and are associated with small body sizes. Density declines, and mean size rises, further down and more particularly further up the shore. Largest animals occur at the top of the shore and in areas experiencing strong wave action, where densities are low. Field experiments showed that increase in density results in a decrease in body weight and an increase in mortality. However, even at a density four times that of the natural population, mortality remained remarkably low, and this is probably a key feature allowing L. unifasciata to penetrate high up the shore. L. unifasciata feeds mainly on lichens and food levels are low over most of the zone occupied by this littorine, rising above and below this zone and being particularly high in the supralittoral immediately above the range of L. unifasciata. Thus, food cannot be a factor limiting the height that L. unifasciata extends up the shore. Experimental caging shows that the standing stock of lichen is inversely related to the density of L. unifasciata. The zonation pattern and size gradient of L. unifasciata may be due to a combination of two factors: a decline of body size due to increasing intraspecific competition at higher densities, and the tendency of L. unifasciata to migrate (probably upwards) away from areas of low food availability. The latter was experimentally demonstrated. L. unifasciata suffers from intense intraspecific competition and is responsible for limiting the availability of its food. Its populations are seemingly not regulated by predators. It borders on a zone of high food availability in which there are no important competitors. These are all circumstances favouring range expansion of the species, to the limits of physiological tolerance, to allow the species to capitalize on the adjacent rich food source.

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