The mean and variance of climate change in the oceans: hidden evolutionary potential under stochastic environmental variability in marine sticklebacks

A method is developed for incorporating the effects of environmental variability and judgmental uncertainty about future production parameters into the design of optimal harvest strategies; these are expressed as curves relating stock size and exploitation rate. For the Skeena River sockeye, the method suggests that optimal strategies are insensitive to judgmental uncertainty about the Ricker stock production parameter, but are very sensitive to management objectives related to the mean and variance of catches. Best possible tradeoffs between mean and variance of catches for the Skeena River are developed, and a simplified strategy is suggested for improving mean catch while reducing year to year variation.

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Climate change and the optimal arrival of migratory birds

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2006.3719 ◽

2006 ◽

Vol 274 (1607) ◽

pp. 269-274 ◽

Cited By ~ 72

Author(s):

Niclas Jonzén ◽

Anders Hedenström ◽

Per Lundberg

Keyword(s):

Climate Change ◽

Arrival Time ◽

Migratory Birds ◽

Life History Evolution ◽

Food Distribution ◽

Arrival Date ◽

Risk Of Mortality ◽

Recent Climate ◽

Mean And Variance ◽

The Mean

Recent climate change has sparked an interest in the timing of biological events, which is a general problem in life-history evolution. Reproduction in many organisms breeding in seasonal environments, e.g. migratory birds, is dependent on the exploitation of a short but rich food supply. If the seasonal timing of the food peak advances owing to climate change, then one would expect the bird to track those changes, hence, initiate migration and breeding earlier. However, when there is competition for territories and a risk of pre-breeding mortality, the optimal response to a shifting food distribution is no longer obvious. We develop a theoretical model to study how the optimal arrival time depends on the mean and variance of the food distribution, the degree of competition for territories and the risk of mortality. In general, the optimal shift in arrival date should never be as extreme as the shift in food peak date. Our results also show that we should expect the high variation of trends in arrival date observed among migratory birds, even if migration and information about climate change were unconstrained.

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Environmental variability and phenology evolution: impacts of climate change and spring onset on reproductive timing in a small mammal

10.7287/peerj.preprints.27435v1 ◽

2018 ◽

Author(s):

Easton R White ◽

Kalle Parvinen ◽

Ulf Dieckmann

Keyword(s):

Climate Change ◽

Evolutionary Dynamics ◽

Environmental Variability ◽

Long Term Effects ◽

Timing Of Reproduction ◽

Juvenile Mortality ◽

Interacting Species ◽

Ochotona Collaris ◽

The Mean

The phenology, or timing of life history events, of organisms affects both ecological and evolutionary dynamics. Recent work has illustrated the effects of climate change on the phenology for many species. Changing selective pressures on phenology can have consequences for species if the reliability of phenological cues decreases or if climate change affects interacting species differentially. There are now numerous examples, in which earlier mean timing of spring has selected for earlier phenology of organisms. However, much less is known about how changes in the variability of spring — and consequently the reliability of cues — might affect species. We built a general model of animal population dynamics to study both the ecology and evolution of phenological events under climate change. We parameterized this model for a population of the collared pika (Ochotona collaris) found in the Yukon, Canada. In line with past work, we show that an earlier timing of spring snowmelt will select for an earlier timing of reproduction. In addition, we show that variability in the onset of spring also selects for earlier reproduction. However, evolution or plasticity in juvenile mortality, due to late snowmelt, can lead to later reproduction. These results highlight the importance of looking at the variability, and not only the mean, in spring onset. The specific relationship between the mean and variability of spring onset coupled with the ability of a population to be plastic or adaptable will determine the long-term effects of climate change on the phenology of species.

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Environmental variability and phenology evolution: impacts of climate change and spring onset on reproductive timing in a small mammal

10.7287/peerj.preprints.27435 ◽

2018 ◽

Author(s):

Easton R White ◽

Kalle Parvinen ◽

Ulf Dieckmann

Keyword(s):

Climate Change ◽

Evolutionary Dynamics ◽

Environmental Variability ◽

Long Term Effects ◽

Timing Of Reproduction ◽

Juvenile Mortality ◽

Interacting Species ◽

Ochotona Collaris ◽

The Mean

The phenology, or timing of life history events, of organisms affects both ecological and evolutionary dynamics. Recent work has illustrated the effects of climate change on the phenology for many species. Changing selective pressures on phenology can have consequences for species if the reliability of phenological cues decreases or if climate change affects interacting species differentially. There are now numerous examples, in which earlier mean timing of spring has selected for earlier phenology of organisms. However, much less is known about how changes in the variability of spring — and consequently the reliability of cues — might affect species. We built a general model of animal population dynamics to study both the ecology and evolution of phenological events under climate change. We parameterized this model for a population of the collared pika (Ochotona collaris) found in the Yukon, Canada. In line with past work, we show that an earlier timing of spring snowmelt will select for an earlier timing of reproduction. In addition, we show that variability in the onset of spring also selects for earlier reproduction. However, evolution or plasticity in juvenile mortality, due to late snowmelt, can lead to later reproduction. These results highlight the importance of looking at the variability, and not only the mean, in spring onset. The specific relationship between the mean and variability of spring onset coupled with the ability of a population to be plastic or adaptable will determine the long-term effects of climate change on the phenology of species.

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Weighted statistical binary patterns for facial feature representation

Applied Intelligence ◽

10.1007/s10489-021-02477-1 ◽

2021 ◽

Author(s):

Hung Phuoc Truong ◽

Thanh Phuong Nguyen ◽

Yong-Guk Kim

Keyword(s):

Comprehensive Evaluation ◽

Facial Feature ◽

Input Image ◽

Feature Representation ◽

Illumination Variation ◽

Straight Line ◽

Mean And Variance ◽

The Mean ◽

Face Datasets ◽

Degraded Images

AbstractWe present a novel framework for efficient and robust facial feature representation based upon Local Binary Pattern (LBP), called Weighted Statistical Binary Pattern, wherein the descriptors utilize the straight-line topology along with different directions. The input image is initially divided into mean and variance moments. A new variance moment, which contains distinctive facial features, is prepared by extracting root k-th. Then, when Sign and Magnitude components along four different directions using the mean moment are constructed, a weighting approach according to the new variance is applied to each component. Finally, the weighted histograms of Sign and Magnitude components are concatenated to build a novel histogram of Complementary LBP along with different directions. A comprehensive evaluation using six public face datasets suggests that the present framework outperforms the state-of-the-art methods and achieves 98.51% for ORL, 98.72% for YALE, 98.83% for Caltech, 99.52% for AR, 94.78% for FERET, and 99.07% for KDEF in terms of accuracy, respectively. The influence of color spaces and the issue of degraded images are also analyzed with our descriptors. Such a result with theoretical underpinning confirms that our descriptors are robust against noise, illumination variation, diverse facial expressions, and head poses.

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Groups and Individuals: Optical Flow Patterns of Broiler Chicken Flocks Are Correlated with the Behavior of Individual Birds

Animals ◽

10.3390/ani11020568 ◽

2021 ◽

Vol 11 (2) ◽

pp. 568

Author(s):

Sabine G. Gebhardt-Henrich ◽

Ariane Stratmann ◽

Marian Stamp Dawkins

Keyword(s):

Optical Flow ◽

Broiler Chicken ◽

Average Length ◽

Flow Patterns ◽

Group Level ◽

Positive Correlation ◽

Water Test ◽

Mean And Variance ◽

The Mean

Group level measures of welfare flocks have been criticized on the grounds that they give only average measures and overlook the welfare of individual animals. However, we here show that the group-level optical flow patterns made by broiler flocks can be used to deliver information not just about the flock averages but also about the proportion of individuals in different movement categories. Mean optical flow provides information about the average movement of the whole flock while the variance, skew and kurtosis quantify the variation between individuals. We correlated flock optical flow patterns with the behavior and welfare of a sample of 16 birds per flock in two runway tests and a water (latency-to-lie) test. In the runway tests, there was a positive correlation between the average time taken to complete the runway and the skew and kurtosis of optical flow on day 28 of flock life (on average slow individuals came from flocks with a high skew and kurtosis). In the water test, there was a positive correlation between the average length of time the birds remained standing and the mean and variance of flock optical flow (on average, the most mobile individuals came from flocks with the highest mean). Patterns at the flock level thus contain valuable information about the activity of different proportions of the individuals within a flock.

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A New Model for the Stochastic Point Reactor: Development and Comparison with Available Models

Energies ◽

10.3390/en14040955 ◽

2021 ◽

Vol 14 (4) ◽

pp. 955

Author(s):

Alamir Elsayed ◽

Mohamed El-Beltagy ◽

Amnah Al-Juhani ◽

Shorooq Al-Qahtani

Keyword(s):

Kinetic Model ◽

Differential Equations ◽

Test Cases ◽

System Of Differential Equations ◽

Reactor Model ◽

Time System ◽

New Model ◽

Reactor Dynamics ◽

Mean And Variance ◽

The Mean

The point kinetic model is a system of differential equations that enables analysis of reactor dynamics without the need to solve coupled space-time system of partial differential equations (PDEs). The random variations, especially during the startup and shutdown, may become severe and hence should be accounted for in the reactor model. There are two well-known stochastic models for the point reactor that can be used to estimate the mean and variance of the neutron and precursor populations. In this paper, we reintroduce a new stochastic model for the point reactor, which we named the Langevin point kinetic model (LPK). The new LPK model combines the advantages, accuracy, and efficiency of the available models. The derivation of the LPK model is outlined in detail, and many test cases are analyzed to investigate the new model compared with the results in the literature.

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Consumer willingness-to-pay for restaurant surcharges to reduce carbon emissions: default and information effects

Agricultural and Resource Economics Review ◽

10.1017/age.2021.7 ◽

2021 ◽

pp. 1-29

Author(s):

Dede Long ◽

Grant H. West ◽

Rodolfo M. Nayga

Keyword(s):

Climate Change ◽

Willingness To Pay ◽

Contingent Valuation ◽

Carbon Emissions ◽

Emission Reduction ◽

Carbon Emission ◽

Dichotomous Choice ◽

Carbon Reduction ◽

The Mean ◽

Agriculture And Food

Abstract The agriculture and food sectors contribute significantly to greenhouse gas emissions. About 15 percent of food-related carbon emissions are channeled through restaurants. Using a contingent valuation (CV) method with double-bounded dichotomous choice (DBDC) questions, this article investigates U.S. consumers’ willingness to pay (WTP) for an optional restaurant surcharge in support of carbon emission reduction programs. The mean estimated WTP for a surcharge is 6.05 percent of an average restaurant check, while the median WTP is 3.64 percent. Our results show that individuals have a higher WTP when the surcharge is automatically added to restaurant checks. We also find that an information nudge—a short climate change script—significantly increases WTP. Additionally, our results demonstrate that there is heterogeneity in treatment effects across consumers’ age, environmental awareness, and economic views. Our findings suggest that a surcharge program could transfer a meaningful amount of the agricultural carbon reduction burden to consumers that farmers currently shoulder.

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Sequential simultaneous estimation of the mean and variance: The rate of convergence

Metrika ◽

10.1007/bf01894759 ◽

1986 ◽

Vol 33 (1) ◽

pp. 291-297 ◽

Cited By ~ 1

Author(s):

N. Mukhopadhyay ◽

G. Vik

Keyword(s):

Rate Of Convergence ◽

Simultaneous Estimation ◽

Mean And Variance ◽

The Mean

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A model for random instantaneous growth on an interval

Journal of Applied Probability ◽

10.2307/3214489 ◽

1991 ◽

Vol 28 (3) ◽

pp. 529-538

Author(s):

M. P. Quine

Keyword(s):

Asymptotic Normality ◽

Instantaneous Growth ◽

Mean And Variance ◽

The Mean

Points arrive in succession on an interval and immediately ‘cover' a region of length ½ to each side (less if they are close to the boundary or to a covered part). The location of a new point is uniformly distributed on the uncovered parts. We study the mean and variance of the total number of points ever formed, in particular as a → 0, in which case we also establish asymptotic normality.

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