scholarly journals Temporal changes in species composition affect a ubiquitous species’ views of patch quality

2019 ◽  
Author(s):  
Ellen K. Bledsoe ◽  
S. K. Morgan Ernest
Keyword(s):  
Time Series ◽  
Species Composition ◽  
Energy Use ◽  
Time Series Data ◽  
Patch Dynamics ◽  
Temporal Changes ◽  
Series Data ◽  
Patch Quality ◽  
Experimental Time Series ◽  
Rodent Community

AbstractMetacommunity theory, particularly the patch dynamics archetype, suggests that an organism’s perspective of patch quality can depend solely on the local competitive environment. Across landscapes, however, shifts in species composition often co-occur with shifts in habitat, making it difficult to disentangle the role of competitors and environment on assessments of patch quality. Using 26 years of rodent community time-series data, we show that perception of patch quality by a small, ubiquitous granivore (Chaetodipus penicillatus) shifted with both spatial and temporal changes in species composition. In the mid-1990s,C. baileyi, a novel competitor, colonized and the study site.C. penicillatuspatch preference shifted with increasing abundance ofC. baileyi, including corresponding changes in estimated survival, probability of movement between patches, and the arrival of new individuals in patches. Changes in energy use on patches due to the establishment ofC. baileyipoint to a potential mechanism for the differences in patch quality perceived byC. penicillatus. These results demonstrate that experimental time-series data can be used to examine how changes in species composition and, specifically, changes in the competitive landscape, can affect perception of patch quality and patch preference.

scholarly journals Transient dynamic phenotypes as criteria for model discrimination: fold-change detection in Rhodobacter sphaeroides chemotaxis

2013 ◽  
Vol 10 (80) ◽  
pp. 20120935 ◽  
Author(s):  
Abdullah Hamadeh ◽  
Brian Ingalls ◽  
Eduardo Sontag
Keyword(s):  
Time Series ◽  
Change Detection ◽  
Rhodobacter Sphaeroides ◽  
Time Series Data ◽  
Series Data ◽  
Transient Dynamic ◽  
Experimental Time ◽  
Theoretical Assumptions ◽  
Experimental Time Series ◽  
Fold Change Detection

The chemotaxis pathway of the bacterium Rhodobacter sphaeroides shares many similarities with that of Escherichia coli . It exhibits robust adaptation and has several homologues of the latter's chemotaxis proteins. Recent theoretical results have correctly predicted that the E. coli output behaviour is unchanged under scaling of its ligand input signal; this property is known as fold-change detection (FCD). In the light of recent experimental results suggesting that R. sphaeroides may also show FCD, we present theoretical assumptions on the R. sphaeroides chemosensory dynamics that can be shown to yield FCD behaviour. Furthermore, it is shown that these assumptions make FCD a property of this system that is robust to structural and parametric variations in the chemotaxis pathway, in agreement with experimental results. We construct and examine models of the full chemotaxis pathway that satisfy these assumptions and reproduce experimental time-series data from earlier studies. We then propose experiments in which models satisfying our theoretical assumptions predict robust FCD behaviour where earlier models do not. In this way, we illustrate how transient dynamic phenotypes such as FCD can be used for the purposes of discriminating between models that reproduce the same experimental time-series data.

Finding Unstable Fixed Points From Time Series Data

2003 ◽  
Author(s):  
Takaaki Maehara ◽  
Mikio Nakai
Keyword(s):  
Time Series ◽  
Fixed Points ◽  
Time Series Data ◽  
Piecewise Linear ◽  
Duffing Oscillator ◽  
Conley Index ◽  
Series Data ◽  
Experimental Time ◽  
Index Pairs ◽  
Experimental Time Series

This study employs topological methods to extract unstable fixed points in phase space from both numerical and experimental time series data. Conley index of an isolated invariant subset and the R-B method can determine unstable fixed points contained in strange attractor from numerical time series data. For experimental time series data, the theorem for the relationship between index pairs and Conley index enables one to predict them with acceptable accuracy. As a corollary, some results for Duffing oscillator and piecewise linear system are shown.

Measuring electric energy efficiency in Portuguese households

2015 ◽  
Vol 26 (3) ◽  
pp. 407-422 ◽  
Author(s):  
Thomas Weyman-Jones ◽  
Júlia Mendonça Boucinha ◽  
Catarina Feteira Inácio
Keyword(s):  
Time Series ◽  
Energy Efficiency ◽  
Energy Demand ◽  
Energy Use ◽  
Time Series Data ◽  
Electric Energy ◽  
Electrical Energy ◽  
Series Data ◽  
Data Set ◽  
Content Type

Purpose – There is a great interest from the European Union in measuring the efficiency of energy use in households, and this is an area where EDP has done research in both data collection and methodology. This paper reports on a survey of electric energy use in Portuguese households, and reviews and extends the analysis of how efficiently households use electrical energy. The purpose of this paper is to evaluate household electrical energy efficiency in different regions using econometric analysis of the survey data. In addition, the same methodology was applied to a time-series data set, to evaluate recent developments in energy efficiency. Design/methodology/approach – The paper describes the application to Portuguese households of a new approach to evaluate energy efficiency, developed by Filippini and Hunt (2011, 2012) in which an econometric energy demand model was estimated to control for exogenous variables determining energy demand. The variation in energy efficiency over time and space could then be estimated by applying econometric efficiency analysis to determine the variation in energy efficiency. Findings – The results obtained allowed the identification of priority regions and consumer bands to reduce inefficiency in electricity consumption. The time-series data set shows that the expected electricity savings from the efficiency measures recently introduced by official authorities were fully realized. Research limitations/implications – This approach gives some guidance on how to introduce electricity saving measures in a more cost effective way. Originality/value – This paper outlines a new procedure for developing useful tools for modelling energy efficiency.

Measurement of Chaotic Behavior of Operator Stabilizing an Inverted Pendulum and Its Fuzzy Identification from Time Series Data

2001 ◽  
Vol 13 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Yoshihiko Kawazoe ◽  
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Fuzzy Inference ◽  
Fuzzy Controller ◽  
Chaotic Behavior ◽  
Series Data ◽  
Experimental Time ◽  
Experimental Time Series ◽  
Simulated Time ◽  
Simulated Time Series

This paper investigates the identification of the chaotic characteristics of human operation with individual difference and the skill difference from the experimental time series data by utilizing fuzzy inference. It shows how to construct rules automatically for a fuzzy controller from experimental time series data of each trial of each operator to identify a controller from human-generated decision-making data. The characteristics of each operator trial were identified fairly well from experimental time series data by utilizing fuzzy reasoning. It was shown that the estimated maximum Lyapunov exponents of simulated time series data using an identified fuzzy controller were positive against embedding dimensions, which means a chaotic phenomenon. It was also recognized that the simulated human behavior have a large amount of disorder according to the result of estimated entropy from the simulated time, series data.

Increasing the quality, comparability and accessibility of phytoplankton species composition time-series data

2015 ◽  
Vol 162 ◽  
pp. 151-160 ◽  
Author(s):  
Adriana Zingone ◽  
Paul J. Harrison ◽  
Alexandra Kraberg ◽  
Sirpa Lehtinen ◽  
Abigail McQuatters-Gollop ◽  
...  
Keyword(s):  
Time Series ◽  
Species Composition ◽  
Time Series Data ◽  
Series Data ◽  
Phytoplankton Species ◽  
Phytoplankton Species Composition
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