Perinate and eggs of a giant caenagnathid dinosaur from the Late Cretaceous of central China

Pu, Hanyong; Zelenitsky, Darla K.; Lü, Junchang; Currie, Philip J.; Carpenter, Kenneth; Xu, Li; Koppelhus, Eva B.; Jia, Shanshan; Xiao, Le; Chuang, Huali; Li, Tianran; Kundrát, Martin; Shen, Caizhi

doi:10.1038/ncomms14952

Cited by 44 publications

(54 citation statements)

References 37 publications

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“…This is a less parsimonious explanation that requires two developmental shifts in tooth formation. Furthermore, it is incongruent with current evidence from Gigantoraptor , the mandible of which is remarkably similar to that of Beibeilong (Ma et al, ; Pu et al, ). The dentaries of Gigantoraptor lack any occlusal ridges or grooves (Ma et al, ), despite presumably being relatively mature compared to Beibeilong and therefore contradict Wang et al's () suggestion.…”

Section: Discussioncontrasting

confidence: 69%

Histology of Caenagnathid (Theropoda, Oviraptorosauria) Dentaries and Implications for Development, Ontogenetic Edentulism, and Taxonomy

Funston

Wilkinson

Simon

et al. 2019

The Anatomical Record

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The fossil record of caenagnathid oviraptorosaurs consists mainly of their fused, complexly sculptured dentaries, but little is known about the growth and development of this diagnostic structure. Previous work has suggested that the ridges and grooves on the occlusal surface are either the vestiges of teeth and their alveoli or were adaptations to increase shearing action during mastication. In addition, the distinctiveness of the dentaries has led to their use for species‐level taxonomy, without a complete understanding of their variation through ontogeny. Here, we describe additional caenagnathid mandibles from the Dinosaur Park Formation of Alberta, Canada, and perform histological analyses to assess relative ontogenetic stage and the nature of the occlusal elaborations. The results show that the mandibular symphysis is synostosed early in ontogeny and does not accurately reflect ontogenetic stage in caenagnathids. In contrast, the presence of cyclical growth marks in a large specimen shows that mandibles can be used for relative histological maturity estimation. Histological features of the ridges of bone surrounding the lingual groove indicate that they are not the vestiges of tooth‐bearing tissues and that caenagnathids did not lose their teeth through ontogeny as suggested in previous work. Instead, increased secondary remodeling in these structures is consistent with their use for food processing. Unexpectedly advanced maturity in a small specimen suggests that at least three caenagnathid species of varying body sizes coexisted in the Dinosaur Park Formation. These results stress the necessity of histological analysis when assessing maturity or ontogenetic trends in fossil material. Anat Rec, 303:918–934, 2020. © 2019 Wiley Periodicals, Inc.

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Section: Discussioncontrasting

confidence: 69%

Histology of Caenagnathid (Theropoda, Oviraptorosauria) Dentaries and Implications for Development, Ontogenetic Edentulism, and Taxonomy

Funston

Wilkinson

Simon

et al. 2019

The Anatomical Record

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“…Multimode quantum memories would greatly help the scaling of quantum networks by decreasing the entanglement distribution time between remote quantum nodes [1,3]. Current research focuses mostly on time multiplexing in rare-earth doped crystals [4,5,6,7,8,9,10,11,12,13] and in spatial multiplexing in atomic gases [14,15,16,17,18,19]. Beyond these demonstrations, rare-earth doped crystals, thanks to their large inhomogeneous broadening, represent a unique quantum system which could also add another degree of freedom for multiplexing, i.e.…”

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confidence: 99%

Quantum Storage of Frequency-Multiplexed Heralded Single Photons

et al. 2019

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We report on the quantum storage of a heralded frequency-multiplexed single photon in an integrated laser-written rare-earth doped waveguide. The single photon contains 15 discrete frequency modes separated by 261 MHz and spaning across 4 GHz. It is obtained from a non-degenerate photon pair created via cavity-enhanced spontaneous down conversion, where the heralding photon is at telecom wavelength and the heralded photon is at 606 nm. The frequency-multimode photon is stored in a praseodymium-doped waveguide using the atomic frequency comb (AFC) scheme, by creating multiple combs within the inhomogeneous broadening of the crystal. Thanks to the intrinsic temporal multimodality of the AFC scheme, each spectral bin includes 9 temporal modes, such that the total number of stored modes is about 130. We demonstrate that the storage preserves the non-classical properties of the single photon, and its normalized frequency spectrum.

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“…Current multi-mode atomic memories focus mainly on spatial multiplexing, e.g. adressing modes with different wavevectors or multiple memory cells in different parts of the cloud [14][15][16][17][18][19][20]. Beyond spatial multiplexing, time multiplexing provides a pratical way to store multiple distinguishable modes in the same ensemble of atoms.…”

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A cold-atom temporally-multiplexed quantum repeater node with cavity-enhanced noise suppression (Conference Presentation)

Heller

Farrera

Heinze

et al. 2020

Quantum Technologies 2020

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Future quantum repeater architectures, capable of efficiently distributing information encoded in quantum states of light over large distances, will benefit from multiplexed photonic quantum memories. In this work we demonstrate a temporally multiplexed quantum repeater node in a laser-cooled cloud of 87 Rb atoms. We employ the DLCZ protocol where pairs of photons and single collective spin excitations (so called spin waves) are created in several temporal modes using a train of write pulses. To make the spin waves created in different temporal modes distinguishable and enable selective readout, we control the dephasing and rephasing of the spin waves by a magnetic field gradient, which induces a controlled reversible inhomogeneous broadening of the involved atomic hyperfine levels. We demonstrate that by embedding the atomic ensemble inside a low finesse optical cavity, the additional noise generated in multi-mode operation is strongly suppressed. By employing feed forward readout, we demonstrate distinguishable retrieval of up to 10 temporal modes. For each mode, we prove non-classical correlations between the first and second photon. Furthermore, an enhancement in rates of correlated photon pairs is observed as we increase the number of temporal modes stored in the memory. The reported capability is a key element of a quantum repeater architecture based on multiplexed quantum memories.Quantum light-matter interfaces are key platforms in the field of quantum information. They provide storage, processing or synchronization of photonic quantum states, which can be used for applications in quantum communication, computation or sensing [1, 2]. One example is optical quantum memories, devices able to store and retrieve photonic quantum states. Multiplexed optical quantum memories are important in order to achieve higher data communication rates, as it is similarly done in conventional classical communications. One particularly interesting application of multiplexed quantum memories is to enhance the entanglement distribution rate in quantum repeaters [3], which in turn also facilitate their practical realization by relaxing the storage time requirements. For this application, the quantum memory should be able to store a large number of distinguishable modes and to read them out selectively. Different degrees of freedom have been considered for the multiplexed modes, such as frequency, space or time. Ensemble-based platforms, where photonic quantum information is mapped onto collective atomic excitations, are well suited for demonstrating quantum information multiplexing.Cold atomic gases are currently one of the best quantum memory platforms with excellent properties demonstrated, including single photon storage and retrieval efficiency up to 90 % [4-8] and storage time up to 220 ms [5,9]. In particular, this system is well suited for realizing a photon pair source with embedded quantum memory following the Duan-Lukin-Cirac-Zoller protocol [10], that can be used as a quantum repeater node [11][12][13]. Current multi...

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Perinate and eggs of a giant caenagnathid dinosaur from the Late Cretaceous of central China

Cited by 44 publications

References 37 publications

Histology of Caenagnathid (Theropoda, Oviraptorosauria) Dentaries and Implications for Development, Ontogenetic Edentulism, and Taxonomy

Histology of Caenagnathid (Theropoda, Oviraptorosauria) Dentaries and Implications for Development, Ontogenetic Edentulism, and Taxonomy

Quantum Storage of Frequency-Multiplexed Heralded Single Photons

A cold-atom temporally-multiplexed quantum repeater node with cavity-enhanced noise suppression (Conference Presentation)

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