Omnidirectional and omnifunctional connectivity analyses with a diverse species pool

AbstractConnectivity among habitat patches in both natural and disturbed landscapes needs to be accounted for in conservation planning for biodiversity maintenance. Yet methods to assess connectivity are often limited, because simulating the dispersal of many species is computationally prohibitive, and current simulations make simplifying assumptions about movement that are potentially erroneous. Here we show how these limits can be circumvented and propose a novel framework for the assessment of omnifunctional and omnidirectional connectivity in a 28000 km2 area in the Laurentian region of Québec, Canada. Our approach relies on (i) the use of Omniscape, an improved version of Circuitscape which allows omnidirectional simulations that better emulate animal movement and (ii) the synthesis of large volume of species-level dispersal simulations through a posteriori clustering of the current intensity. Our analysis reveals that the movement of 93 species evaluated can be clustered into three functional dispersal guilds, corresponding to mostly aquatic species, terrestrial species able to use aquatic environments, and strictly terrestrial species. These functional guilds do not share connectivity hotspots, suggesting that corridor planning would need to account for the multiplicity of dispersal strategies. Although this approach requires a large volume of computing resources, it provides richer information on which landscape features are critical to maintain or need to be regenerated for broader biodiversity maintenance goals.

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Eigenvectors, Circulation, and Linear Instabilities for Planetary Science in 3 Dimensions (ECLIPS3D)

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935582 ◽

2019 ◽

Vol 631 ◽

pp. A36 ◽

Cited By ~ 3

Author(s):

F. Debras ◽

N. Mayne ◽

I. Baraffe ◽

T. Goffrey ◽

J. Thuburn

Keyword(s):

Steady State ◽

Energy Equation ◽

Planetary Science ◽

Staggered Grid ◽

A Posteriori ◽

Linear Processes ◽

Hot Jupiters ◽

Global Circulation Models ◽

Simplifying Assumptions ◽

Steady Solutions

Context. The study of linear waves and instabilities is necessary to understand the physical evolution of an atmosphere, and can provide physical interpretation of the complex flows found in simulations performed using global circulation models (GCMs). In particular, the acceleration of superrotating flow at the equator of hot Jupiters has mostly been studied under several simplifying assumptions, the relaxing of which may impact final results. Aims. We develop and benchmark a publicly available algorithm to identify the eigenmodes of an atmosphere around any initial steady state. We also solve for linear steady states indicated to be essential in existing theories of the acceleration of hot Jupiter superrotation. Methods. We linearise the hydrodynamical equations of a planetary atmosphere in a steady state with arbitrary velocities and thermal profile. We then discretise the linearised equations on an appropriate staggered grid, and solve for eigenvectors and linear steady solutions with the use of a parallel library for linear algebra: ScaLAPACK. We also implement a posteriori calculation of an energy equation in order to obtain more information on the underlying physics of the mode. Results. Our code is tested using classical wave and instability test cases in multiple geometries (2D, 3D, two-layer equivalent depth). The steady linear circulation calculations also reproduce expected results for the atmosphere of hot Jupiters. We finally show the robustness of our energy equation, and its power to obtain physical insight into the modes. Conclusions. We developed and tested a code for the study of linear processes in planetary atmospheres with an arbitrary steady state. The calculation of an a posteriori energy equation provides both increased robustness and physical meaning to the obtained eigenmodes. This code can be applied to various problems, and notably used to further study the initial spin up of superrotation of GCM simulations of hot Jupiters.

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An analytic solution of the non-linear equation∇2λ(r)=f(λ)and its application to the ion-atmosphere theory of strong electrolytes

International Journal of Mathematics and Mathematical Sciences ◽

10.1155/s016117128100015x ◽

1981 ◽

Vol 4 (2) ◽

pp. 209-277 ◽

Cited By ~ 1

Author(s):

S. N. Bagchi

Keyword(s):

Distribution Function ◽

Analytic Solution ◽

Extensive Study ◽

Distribution Functions ◽

A Posteriori ◽

Consistent Theory ◽

Generalized Poisson ◽

Primary Object ◽

Simplifying Assumptions ◽

Strong Electrolytes

For a long time the formulation of a mathematically consistent statistical mechanical theory for a system of charged particles had remained a formidable unsolved problem. Recently, the problem had been satisfactorily solved, (see Bagchi [1] [2]) ,by utilizing the concept of ion-atmosphere and generalized Poisson-Boltzmann (PB) equation. Although the original Debye-Hueckel (DH) theory of strong electrolytes [3] cannot be accepted as a consistent theory, neither mathematically nor physically, modified DH theory, in which the exclusion volumes of the ions enter directly into the distribution functions, had been proved to be mathematically consistent. It also yielded reliable physical results for both thermodynamic and transport properties of electrolytic solutions. Further, it has already been proved by the author from theoretical considerations (cf. Bagchi [4])as well as from a posteriori verification (see refs. [1] [2]) that the concept of ion-atmosphere and the use of PB equation retain their validities generally. Now during the past 30 years, for convenice of calculations, various simplified versions of the original Dutta-Bagchi distribution function (Dutta & Bagchi [5])had been used successfully in modified DH theory of solutions of strong electrolytes. The primary object of this extensive study, (carried out by the author during 1968-73), was to decide a posteriori by using the exact analytic solution of the relevant PB equation about the most suitable, yet theoretically consistent, form of the distribution function. A critical analysis of these results eventually led to the formulation of a new approach to the statistical mechanics of classical systems, (see Bagchi [2]), In view of the uncertainties inherent in the nature of the system to be discussed below, it is believed that this voluminous work, (containing 35 tables and 120 graphs), in spite of its legitimate simplifying assumptions, would be of great assistance to those who are interested in studying the properties of ionic solutions from the standpoint of a physically and mathematically consistent theory.

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Behavioral temperature regulation by aquatic ectotherms during hypoxia

Canadian Journal of Zoology ◽

10.1139/z88-389 ◽

1988 ◽

Vol 66 (12) ◽

pp. 2649-2652 ◽

Cited By ~ 24

Author(s):

R. Keith Dupré ◽

Stephen C. Wood

Keyword(s):

Body Temperature ◽

Oxygen Demand ◽

Ambystoma Tigrinum ◽

Aquatic Environments ◽

Low Oxygen ◽

Tiger Salamanders ◽

Diverse Species ◽

Hypothermic Response ◽

The Face ◽

Widespread Phenomenon

Terrestrial animals lower their body temperature by behavioral and (or) physiological means in response to environmental or anemic hypoxia. Because hypoxia is common in some aquatic environments, temperature selection by two aquatic ectotherms, paedomorphic tiger salamanders (Ambystoma tigrinum) and crayfish (Procambarus simulans), was examined during environmental hypoxia in an aquatic thermal gradient. Both species selected lower temperatures when exposed to an environment with a [Formula: see text] of about 37 Torr (4.9 kPa). These data suggest that the lowering of body temperature, and thus oxygen demand, in the face of a low oxygen availability may be an adaptive response in heterothermal aquatic environments. The available data for diverse species show that the hypothermic response to hypoxia is a taxonomically widespread phenomenon occurring in both water- and air-breathing animals.

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Practical Correction of Three Fold Astigmatism in the Philips CM TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100164556 ◽

1996 ◽

Vol 54 ◽

pp. 418-419

Author(s):

Arno J. Bleeker ◽

Mark H.F. Overwijk ◽

Max T. Otten

Keyword(s):

Optical Properties ◽

Phase Contrast ◽

The Other ◽

Objective Lens ◽

Symmetric Part ◽

A Posteriori ◽

Contrast Transfer Function ◽

High Brightness ◽

Rotationally Symmetric ◽

Brightness Field

With the improvement of the optical properties of the modern TEM objective lenses the point resolution is pushed beyond 0.2 nm. The objective lens of the CM300 UltraTwin combines a Cs of 0. 65 mm with a Cc of 1.4 mm. At 300 kV this results in a point resolution of 0.17 nm. Together with a high-brightness field-emission gun with an energy spread of 0.8 eV the information limit is pushed down to 0.1 nm. The rotationally symmetric part of the phase contrast transfer function (pctf), whose first zero at Scherzer focus determines the point resolution, is mainly determined by the Cs and defocus. Apart from the rotationally symmetric part there is also the non-rotationally symmetric part of the pctf. Here the main contributors are not only two-fold astigmatism and beam tilt but also three-fold astigmatism. The two-fold astigmatism together with the beam tilt can be corrected in a straight-forward way using the coma-free alignment and the objective stigmator. However, this only works well when the coefficient of three-fold astigmatism is negligible compared to the other aberration coefficients. Unfortunately this is not generally the case with the modern high-resolution objective lenses. Measurements done at a CM300 SuperTwin FEG showed a three fold-astigmatism of 1100 nm which is consistent with measurements done by others. A three-fold astigmatism of 1000 nm already sinificantly influences the image at a spatial frequency corresponding to 0.2 nm which is even above the point resolution of the objective lens. In principle it is possible to correct for the three-fold astigmatism a posteriori when through-focus series are taken or when off-axis holography is employed. This is, however not possible for single images. The only possibility is then to correct for the three-fold astigmatism in the microscope by the addition of a hexapole corrector near the objective lens.

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Selected Abstracts of Recent Research in Stuttering

Perspectives on Fluency and Fluency Disorders ◽

10.1044/ffd9.1.5 ◽

1999 ◽

Vol 9 (1) ◽

pp. 5-6

Author(s):

Carrie Bain ◽

Nan Bernstein Ratner

Keyword(s):

Large Volume ◽

Clinical Relevance

Due to the large volume of fluency-related publications since the last column, we have chosen to highlight those articles of highest potential clinical relevance.

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