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Université de Fribourg

A review of the fossil record of basal mesozoic turtles

Joyce, Walter G.

In: Bulletin of the Peabody Museum of Natural History, 2017, vol. 58, no. 1, p. 65–113

Turtles (Testudinata) are the clade of amniotes characterized by a complete turtle shell. New insights into the phylogeny of the group have revealed that a diverse assemblage of fossil turtles populate the stem lineage that lead to the turtle crown (Testudines). To aid communication, the terms Mesochelydia and Perichelydia are herein defined for two internested clades more inclusive than...

Université de Fribourg

A Jurassic stem pleurodire sheds light on the functional origin of neck retraction in turtles

Anquetin, Jérémy ; Tong, Haiyan ; Claude, Julien

In: Scientific Reports, 2017, vol. 7, p. 42376

Modern turtles are composed of two monophyletic groups, notably diagnosed by divergent neck retraction mechanisms. Pleurodires (side-necked turtles) bend their neck sideways and protect their head under the anterior margin of the carapace. Cryptodires (hidden-necked turtles) withdraw their neck and head in the vertical plane between the shoulder girdles. These two mechanisms of neck...

Université de Fribourg

Bis-retinoid A2E induces an increase of basic fibroblast growth factor via inhibition of extracellular signal-regulated kinases 1/2 pathway in retinal pigment epithelium cells and facilitates phagocytosis

Balmer, Delphine ; Bapst-Wicht, Linda ; Pyakurel, Aswin ; Emery, Martine ; Nanchen, Natacha ; Bochet, Christian G. ; Roduit, Raphael

In: Frontiers in Aging Neuroscience, 2017, vol. 9, p. -

Age-related macular degeneration (ARMD) is the leading cause of vision loss in developed countries. Hallmarks of the disease are well known; indeed, this pathology is characterized by lipofuscin accumulation, is principally composed of lipid-containing residues of lysosomal digestion. The N-retinyl-N-retinylidene ethanolamine (A2E) retinoid which is thought to be a cytotoxic component for RPE...

Université de Fribourg

A toothed turtle from the Late Jurassic of China and the global biogeographic history of turtles

Joyce, Walter G. ; Rab, Márton ; Clark, James M. ; Xu, Xing

In: BMC Evolutionary Biology, 2016, vol. 16, p. 236

Turtles (Testudinata) are a successful lineage of vertebrates with about 350 extant species that inhabit all major oceans and landmasses with tropical to temperate climates. The rich fossil record of turtles documents the adaptation of various sub- lineages to a broad range of habitat preferences, but a synthetic biogeographic model is still lacking for the group.Results: We herein describe a...

Université de Fribourg

Double K-shell photoionization and hypersatellite x-ray transitions of 12⩽Z⩽23 atoms

Hoszowska, Joanna ; Dousse, Jean-Claude ; Cao, Wei ; Fennane, Karima ; Kayser, Yves ; Szlachetko, Monika ; Szlachetko, Jakub ; Kavčič, Matjaz

In: Physical Review A, 2010, vol. 82, no. 6, p. 063408

Single-photon double K-shell ionization of low-Z neutral atoms in the range 12⩽Z⩽23 is investigated. The experimental method was based on measurements of the high- resolution Kαh hypersatellite x-ray spectra following the radiative decay of the K-shell double-vacancy states excited by monochromatic synchrotron radiation. The photon energy dependence of the double K-shell ionization was...

Université de Fribourg

Lifetimes of doubly K -shell ionized states

Polasik, M . ; Słabkowska, K. ; Kozioł, K. ; Starosta, J. ; Dousse, Jean-Claude ; Hoszowska, Joanna ; Rzadkiewicz, J.

In: Physica Scripta, 2011, vol. 2011, no. T144, p. 014021

The present work provides a reliable interpretation of the Khα₁/Khα₂ intensity ratios and an explanation of the lifetime values for K-shell hollow atoms based on an advanced theoretical analysis (using extensive multiconfiguration Dirac–Fock calculations with the inclusion of the transverse Breit interaction and quantum electrodynamics ...

Université de Fribourg

First report of Plesiochelys etalloni and Tropidemys langii from the Late Jurassic of the UK and the palaeobiogeography of plesiochelyid turtles

Anquetin, Jérémy ; Chapman, Sandra D.

In: Royal Society Open Science, 2016, vol. 3, no. 1, p. 150470

Plesiochelyidae is a clade of relatively large coastal marine turtles that inhabited the shallow epicontinental seas that covered western Europe during the Late Jurassic. Although the group has been reported from many deposits, the material is rarely identified at the species level. Here, we describe historical plesiochelyid material from the Kimmeridge Clay Formation of England and compare...

Université de Fribourg

A new baenid turtle from the early Paleocene (Torrejonian) of New Mexico and a species-level phylogenetic analysis of Baenidae

Lyson, Tyler R. ; Joyce, Walter G. ; Lucas, Spencer G. ; Sullivan, Robert M.

In: Journal of Paleontology, 2016, vol. 90, no. 2, p. 305–316

New cranial and postcranial material of the baenid turtle Neurankylus from the Paleocene Nacimiento Formation (Torrejonian NALMA) of northwestern New Mexico represents a new species, Neurankylus torrejonensis. The material consists of a fragmented but mostly complete skull, a partial carapace and plastron, portions of both humeri, a partial pelvis, a complete right femur, and a distal phalanx....

Université de Fribourg

Acute stress is detrimental to heart regeneration in zebrafish

Sallin, Pauline ; Jaźwińska, Anna

In: Open Biology, 2016, vol. 6, no. 3, p. 160012

Psychological stress is one of the factors associated with human cardiovascular disease. Here, we demonstrate that acute perceived stress impairs the natural capacity of heart regeneration in zebrafish. Beside physical and chemical disturbances, intermittent crowding triggered an increase in cortisol secretion and blocked the replacement of fibrotic tissue with new myocardium. Pharmacological...

Université de Fribourg

A review of the fossil record of turtles of the clade Pan-Chelydridae

Joyce, Walter G.

In: Bulletin of the Peabody Museum of Natural History, 2016, vol. 57, no. 1, p. 21–56

Turtles of the total clade Pan-Chelydridae have a relatively sparse fossil record that reaches back to the Late Cretaceous (Santonian). The clade was only present in North America during the Cretaceous but spread along unclear routes to Asia and Europe during the Paleocene, only to go extinct on those continents by the end of the Pliocene. Final dispersal to South America took place at some time...