scholarly journals An example of phenotypic adherence to the island rule? – Anticosti gray jays are heavier but not structurally larger than mainland conspecifics

2015 ◽  
Vol 5 (17) ◽  
pp. 3687-3694 ◽  
Author(s):  
Dan Strickland ◽  
D. Ryan Norris
Keyword(s):  
Island Rule ◽  
Gray Jays

scholarly journals Islands and stretched horizon

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Yoshinori Matsuo
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Entanglement Entropy ◽  
Total System ◽  
Island Rule ◽  
Asymptotically Flat ◽  
Flat Spacetime ◽  
Ads Spacetime ◽  
Hole Geometry

Abstract Recently it was proposed that the entanglement entropy of the Hawking radiation contains the information of a region including the interior of the event horizon, which is called “island.” In studies of the entanglement entropy of the Hawking radiation, the total system in the black hole geometry is separated into the Hawking radiation and black hole. In this paper, we study the entanglement entropy of the black hole in the asymptotically flat Schwarzschild spacetime. Consistency with the island rule for the Hawking radiation implies that the information of the black hole is located in a different region than the island. We found an instability of the island in the calculation of the entanglement entropy of the region outside a surface near the horizon. This implies that the region contains all the information of the total system and the information of the black hole is localized on the surface. Thus the surface would be interpreted as the stretched horizon. This structure also resembles black holes in the AdS spacetime with an auxiliary flat spacetime, where the information of the black hole is localized at the interface between the AdS spacetime and the flat spacetime.

scholarly journals Replica wormholes for an evaporating 2D black hole

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Kanato Goto ◽  
Thomas Hartman ◽  
Amirhossein Tajdini
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Path Integral ◽  
Island Rule ◽  
Technical Challenge ◽  
Local Boundary ◽  
Lorentzian Signature ◽  
Special Cases ◽  
Non Local ◽  
Non Local Equations

Abstract Quantum extremal islands reproduce the unitary Page curve of an evaporating black hole. This has been derived by including replica wormholes in the gravitational path integral, but for the transient, evaporating black holes most relevant to Hawking’s paradox, these wormholes have not been analyzed in any detail. In this paper we study replica wormholes for black holes formed by gravitational collapse in Jackiw-Teitelboim gravity, and confirm that they lead to the island rule for the entropy. The main technical challenge is that replica wormholes rely on a Euclidean path integral, while the quantum extremal islands of an evaporating black hole exist only in Lorentzian signature. Furthermore, the Euclidean equations for the Schwarzian mode are non-local, so it is unclear how to connect to the local, Lorentzian dynamics of an evaporating black hole. We address these issues with Schwinger-Keldysh techniques and show how the non-local equations reduce to the local ‘boundary particle’ description in special cases.

scholarly journals Island rule and bone metabolism in fossil murines from Timor

2020 ◽  
Vol 129 (3) ◽  
pp. 570-586 ◽  
Author(s):  
Justyna J Miszkiewicz ◽  
Julien Louys ◽  
Robin M D Beck ◽  
Patrick Mahoney ◽  
Ken Aplin ◽  
...  
Keyword(s):  
Body Weight ◽  
Bone Metabolism ◽  
Late Quaternary ◽  
Phylogenetic Signal ◽  
Skeletal Growth ◽  
Island Rule ◽  
Slow Pace ◽  
Osteocyte Lacunae ◽  
Murine Rodents ◽  
Negative Relationships

Abstract Skeletal growth rates reconstructed from bone histology in extinct insular hippopotamids, elephants, bovids and sauropods have been used to infer dwarfism as a response to island conditions. Limited published records of osteocyte lacunae densities (Ot.Dn), a proxy for living osteocyte proliferation, have suggested a slower rate of bone metabolism in giant mammals. Here, we test whether insularity might have affected bone metabolism in a series of small to giant murine rodents from Timor. Ten adult femora were selected from a fossil assemblage dated to the Late Quaternary (~5000–18 000 years old). Femur morphometric data were used in computing phylogenetically informed body mass regressions, although the phylogenetic signal was very low (Pagel’s λ = 0.03). Estimates of body weight calculated from these femora ranged from 75 to 1188 g. Osteocyte lacunae densities from histological sections of the midshaft femur were evaluated against bone size and estimated body weight. Statistically significant (P < 0.05) and strongly negative relationships between Ot.Dn, femur size and estimated weight were found. Larger specimens were characterized by lower Ot.Dn, indicating that giant murines from Timor might have had a relatively slow pace of bone metabolic activity, consistent with predictions made by the island rule.

Erroneous choice and foregone gains in hoarding gray jays ( Perisoreus canadensis )

2000 ◽  
Vol 3 (3) ◽  
pp. 127-134 ◽  
Author(s):  
T. A. Waite ◽  
K. L. Field
Keyword(s):  
Gray Jays ◽  
Perisoreus Canadensis

scholarly journals Palaeohistology reveals a slow pace of life for the dwarfed Sicilian elephant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Meike Köhler ◽  
Victoria Herridge ◽  
Carmen Nacarino-Meneses ◽  
Josep Fortuny ◽  
Blanca Moncunill-Solé ◽  
...  
Keyword(s):  
Life History ◽  
Body Mass ◽  
Growth Period ◽  
Extended Period ◽  
Island Rule ◽  
Rule Based ◽  
Age At First Reproduction ◽  
Slow Pace ◽  
First Reproduction ◽  
Adaptive Shifts

AbstractThe 1-m-tall dwarf elephant Palaeoloxodon falconeri from the Pleistocene of Sicily (Italy) is an extreme example of insular dwarfism and epitomizes the Island Rule. Based on scaling of life-history (LH) traits with body mass, P. falconeri is widely considered to be ‘r-selected’ by truncation of the growth period, associated with an early onset of reproduction and an abbreviated lifespan. These conjectures are, however, at odds with predictions from LH models for adaptive shifts in body size on islands. To settle the LH strategy of P. falconeri, we used bone, molar, and tusk histology to infer growth rates, age at first reproduction, and longevity. Our results from all approaches are congruent and provide evidence that the insular dwarf elephant grew at very slow rates over an extended period; attained maturity at the age of 15 years; and had a minimum lifespan of 68 years. This surpasses not only the values predicted from body mass but even those of both its giant sister taxon (P. antiquus) and its large mainland cousin (L. africana). The suite of LH traits of P. falconeri is consistent with the LH data hitherto inferred for other dwarfed insular mammals. P. falconeri, thus, not only epitomizes the Island Rule but it can also be viewed as a paradigm of evolutionary change towards a slow LH that accompanies the process of dwarfing in insular mammals.

scholarly journals Weight-carrying Ability and Caching Behavior of Gray Jays, Perisoreus canadensis: Adaptations to Boreal Winters

2005 ◽  
Vol 119 (1) ◽  
pp. 101 ◽  
Author(s):  
Lynn L. Rogers
Keyword(s):  
Body Weight ◽  
Boreal Forest ◽  
Corvus Corax ◽  
Gray Jays ◽  
Risk Of Predation ◽  
Perisoreus Canadensis ◽  
Flight Loads ◽  
Insect Activity ◽  
Weight Carrying ◽  
Ability And Willingness

During 16 August to 21 September 1984, I determined how Gray Jays (Perisoreus canadensis) carried flight-loads of different weights. Three individually identifiable Gray Jays weighing 60, 68, and 80 grams, used their bills to carry flight-loads weighing up to 33 percent of bodyweight but transferred heavier flight-loads from their bills to their feet 1-2 meters after takeoff. They had difficulty carrying flight-loads over 57 percent of bodyweight, and none attempted to carry flight-loads over 66 percent of bodyweight. By using their feet to bring heavy flight-loads closer to the center of lift, Gray Jays can carry heavier loads of meat, relative to body weight, than can Common Ravens (Corvus corax) which compete with Gray Jays at carcasses in winter and which do not carry objects with their feet. During 1969-2003, year-round observations near the southern edge of the Gray Jay range in northeastern Minnesota showed that caching behavior begins in August, continues over-winter, and ends at the onset of insect activity and green-up in early May. Gray Jays’ propensity to approach larger animals, including people, may not indicate unwariness but rather a superior ability and willingness to assess risks and food benefits. In the boreal forest in winter, risk of starvation is greater and risk of predation is lower than in relatively food-rich ecoregions farther south.

scholarly journals Reply to Brian and Walker-Hale: Support for the island rule does not hide morphological disparity in insular plants

2019 ◽  
Vol 116 (50) ◽  
pp. 24931-24932
Author(s):  
M. Biddick ◽  
K. C. Burns
Keyword(s):  
Island Rule ◽  
Morphological Disparity

The island rule and a research agenda for studying ecogeographical patterns

2006 ◽  
Vol 33 (9) ◽  
pp. 1503-1510 ◽  
Author(s):  
Mark V. Lomolino ◽  
Dov F. Sax ◽  
Brett R. Riddle ◽  
James H. Brown
Keyword(s):  
Research Agenda ◽  
Island Rule

Repeated Human Intrusion and the Potential for Nest Predation by Gray Jays

2002 ◽  
Vol 66 (2) ◽  
pp. 372 ◽  
Author(s):  
Kevin J. Gutzwiller ◽  
Samuel K. Riffell ◽  
Stanley H. Anderson
Keyword(s):  
Nest Predation ◽  
Gray Jays

scholarly journals The “Island Rule” and Deep-Sea Gastropods: Re-Examining the Evidence

PLoS ONE ◽  
2010 ◽  
Vol 5 (1) ◽  
pp. e8776 ◽  
Author(s):  
John J. Welch
Keyword(s):  
Deep Sea ◽  
Island Rule
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