scholarly journals How animals distribute themselves in space: energy landscapes of Antarctic avian predators

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Juan F. Masello ◽  
Andres Barbosa ◽  
Akiko Kato ◽  
Thomas Mattern ◽  
Renata Medeiros ◽  
...  
Keyword(s):  
Breeding Success ◽  
Physiological Stress ◽  
Energy Landscape ◽  
Energy Gain ◽  
Population Trend ◽  
Population Trends ◽  
Energy Costs ◽  
Energy Landscapes ◽  
Animal Populations ◽  
Positive Population

Abstract Background Energy landscapes provide an approach to the mechanistic basis of spatial ecology and decision-making in animals. This is based on the quantification of the variation in the energy costs of movements through a given environment, as well as how these costs vary in time and for different animal populations. Organisms as diverse as fish, mammals, and birds will move in areas of the energy landscape that result in minimised costs and maximised energy gain. Recently, energy landscapes have been used to link energy gain and variable energy costs of foraging to breeding success, revealing their potential use for understanding demographic changes. Methods Using GPS-temperature-depth and tri-axial accelerometer loggers, stable isotope and molecular analyses of the diet, and leucocyte counts, we studied the response of gentoo (Pygoscelis papua) and chinstrap (Pygoscelis antarcticus) penguins to different energy landscapes and resources. We compared species and gentoo penguin populations with contrasting population trends. Results Between populations, gentoo penguins from Livingston Island (Antarctica), a site with positive population trends, foraged in energy landscape sectors that implied lower foraging costs per energy gained compared with those around New Island (Falkland/Malvinas Islands; sub-Antarctic), a breeding site with fluctuating energy costs of foraging, breeding success and populations. Between species, chinstrap penguins foraged in sectors of the energy landscape with lower foraging costs per bottom time, a proxy for energy gain. They also showed lower physiological stress, as revealed by leucocyte counts, and higher breeding success than gentoo penguins. In terms of diet, we found a flexible foraging ecology in gentoo penguins but a narrow foraging niche for chinstraps. Conclusions The lower foraging costs incurred by the gentoo penguins from Livingston, may favour a higher breeding success that would explain the species’ positive population trend in the Antarctic Peninsula. The lower foraging costs in chinstrap penguins may also explain their higher breeding success, compared to gentoos from Antarctica but not their negative population trend. Altogether, our results suggest a link between energy landscapes and breeding success mediated by the physiological condition.

scholarly journals Universally bistable shells with nonzero Gaussian curvature for two-way transition waves

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nikolaos Vasios ◽  
Bolei Deng ◽  
Benjamin Gorissen ◽  
Katia Bertoldi
Keyword(s):  
Gaussian Curvature ◽  
Energy Landscape ◽  
Propagation Distance ◽  
Energy Landscapes ◽  
Bending Energy ◽  
Nonlinear Dynamic Response ◽  
One Dimensional ◽  
Doubly Curved Shells ◽  
Doubly Curved ◽  
The Waves

AbstractMulti-welled energy landscapes arising in shells with nonzero Gaussian curvature typically fade away as their thickness becomes larger because of the increased bending energy required for inversion. Motivated by this limitation, we propose a strategy to realize doubly curved shells that are bistable for any thickness. We then study the nonlinear dynamic response of one-dimensional (1D) arrays of our universally bistable shells when coupled by compressible fluid cavities. We find that the system supports the propagation of bidirectional transition waves whose characteristics can be tuned by varying both geometric parameters as well as the amount of energy supplied to initiate the waves. However, since our bistable shells have equal energy minima, the distance traveled by such waves is limited by dissipation. To overcome this limitation, we identify a strategy to realize thick bistable shells with tunable energy landscape and show that their strategic placement within the 1D array can extend the propagation distance of the supported bidirectional transition waves.

scholarly journals Variation among colonies in breeding success and population trajectories of wandering albatrosses Diomedea exulans at South Georgia

Polar Biology ◽  
2021 ◽  
Author(s):  
Carola Rackete ◽  
Sally Poncet ◽  
Stephanie D. Good ◽  
Richard A. Phillips ◽  
Ken Passfield ◽  
...  
Keyword(s):  
Body Condition ◽  
Breeding Success ◽  
Population Trends ◽  
Contributing Factors ◽  
South Georgia ◽  
Vortex Model ◽  
Demographic Rates ◽  
Diomedea Exulans ◽  
Adult Body ◽  
Provisioning Rate

AbstractThe wandering albatross, Diomedea exulans, is a globally threatened species breeding at a number of sites within the Southern Ocean. Across the South Georgia archipelago, there are differences in population trends even at closely located colonies. Between 1999 and 2018 the largest colony, at Bird Island, declined at 3.01% per annum, while in the Bay of Isles, the decline was 1.44% per annum. Using mean demographic rates from a 31-year study at Bird Island and an 11-year study of breeding success at Prion Island in the Bay of Isles in a VORTEX model, we show that differences in breeding success do not fully explain observed differences in population trends. Other potential contributing factors are differential use of foraging areas, with possible knock-on effects on adult body condition, provisioning rate and breeding success, or on bycatch rates of adults or immatures.

scholarly journals A statistical assessment of population trends for data deficient Mexican amphibians

2014 ◽  
Author(s):  
Esther Quintero ◽  
Anne E. Thessen ◽  
Paulina Arias-Caballero ◽  
Bárbara Ayala-Orozco
Keyword(s):  
Random Forests ◽  
Demographic Data ◽  
Population Trend ◽  
Population Trends ◽  
Conservation Priorities ◽  
Risk Category ◽  
Conservation Action ◽  
Amphibian Species ◽  
Complex Processes ◽  
Data Deficient

Background: Mexico is the fourth richest country in amphibians and the second country with the highest quantity of threatened amphibian species, and this number could be higher as many species are too poorly known to be accurately assigned to a risk category. The absence of a risk status or an unknown population trend can slow or halt conservation action, so it is vital to develop tools that in the absence of specific demographic data can assess a species’ risk of extinction, population trend, and to better understand which variables increase their vulnerability. Recent studies have demonstrated that the risk of species decline depends on extrinsic and intrinsic trait, thus including both of them for assessing extinction might render more accurate assessment of threat. Methods: In this study harvested data from the Encyclopedia of Life (EOL) and the published literature for Mexican amphibians and used these data to assess the population trend of some of the Mexican species that have been assigned to the Data Deficient category of the IUCN using Random Forests, a Machine Learning method that gives a prediction of complex processes and identifies the most important variables that account for the predictions. Results: Our results show that most data deficient Mexican amphibians have decreasing population trends. We found that Random Forests is a solid and accurate way to identify species with decreasing population trends when no demographic data is available. Moreover, we point the most important variables that make species more vulnerable for extinction. This exercise is a very valuable first step in assigning conservation priorities for poorly known species.

Black-Faced Spoonbill Platalea minor Population Trends, Breeding Success, and Nest Characteristics in the Chilsan Archipelago, South Korea

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Seok-Jun Son ◽  
Ki-Sup Lee ◽  
In-Ki Kwon ◽  
Jung-Hoon Kang ◽  
Sung-Kyung Lee ◽  
...  
Keyword(s):  
South Korea ◽  
Breeding Success ◽  
Population Trends ◽  
Minor Population

scholarly journals Graphene and novel graphitic ZnO and ZnS nanofilms: the energy landscape, non-stoichiometry and water dissociation

2019 ◽  
Vol 1 (5) ◽  
pp. 1924-1935
Author(s):  
Sergio Conejeros ◽  
Neil L. Allan ◽  
Frederik Claeyssens ◽  
Judy N. Hart
Keyword(s):  
Ab Initio ◽  
Energy Landscape ◽  
Adsorbed Water ◽  
Water Dissociation ◽  
Energy Landscapes ◽  
Zns Films

Ab initio energy landscapes of thin ZnO and ZnS films reveal new structures, non-stoichiometry and different behaviour of adsorbed water.

The energy landscape concept and its implications for synthesis planning

2014 ◽  
Vol 86 (6) ◽  
pp. 883-898 ◽  
Author(s):  
Martin Jansen
Keyword(s):  
Energy Landscape ◽  
Chemical Compounds ◽  
Materials Chemistry ◽  
Energy Landscapes ◽  
Free Energies ◽  
Lack Of Control ◽  
Synthesis Planning ◽  
Materials Research ◽  
Potential Energy Landscapes ◽  
Almost All

AbstractSynthesis of novel solids, in a chemical sense, is one of the spearheads of innovation in materials research. However, such an undertaking is substantially impaired by lack of control and predictability. We present a concept that points the way towards rational planning of syntheses in solid state and materials chemistry. The foundation of our approach is the representation of the whole material world, i.e., the known and not-yet-known chemical compounds, on an energy landscape, which implies information about the free energies of these configurations. From this it follows at once that all chemical compounds capable of existence (both thermodynamically stable and metastable ones) are already present in virtuo in this landscape. For the first step of synthesis planning, i.e., the identification of candidates that are capable of existence, we computationally search the respective potential energy landscapes for (meta)stable structure candidates. Recently we have extended our techniques to finite temperatures and pressures and calculated phase diagrams, including metastable manifestations of matter, without resorting to any experimental pre-information. The conception developed is physically consistent, and its feasibility has been proven. Applying appropriate experimental tools has enabled us to realize, e.g., elusive Na3 N, including almost all of its predicted polymorphs, many years after the predictions were published.

Energy landscapes for cooperative processes: nearly ideal glass transitions, liquid–liquid transitions and folding transitions

2004 ◽  
Vol 363 (1827) ◽  
pp. 415-432 ◽  
Author(s):  
C. Austen Angell
Keyword(s):  
Phase Transitions ◽  
Liquid Phase ◽  
Point Defects ◽  
Laboratory Experiments ◽  
Constant Pressure ◽  
Energy Landscape ◽  
Experimental Methods ◽  
Glass Transitions ◽  
Energy Landscapes ◽  
Cooperative Processes

We describe basic phenomenology in the physics of supercooling liquids at constant volume (most simulations), and at constant pressure (most laboratory experiments) before focusing attention on the exceptional cases that exhibit liquid–liquid phase transitions on constant–pressure cooling. We give evidence for point defects in glasses and liquids near T g . Models based on defects predict transitions with density gaps in constant–pressure systems. We describe the energy landscape representation of such systems. Water, in these terms, is post–critical, and its nearly ideal glass formation can be related to nucleation–free protein ‘funnel–folding’. For nucleated folding of proteins, a pseudo–gap should be present. Experimental methods of distinguishing between alternative folding scenarios are described.

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