Title: Bathysciadium pacificum Dall, 1908 from the bathyal of Oregon: range extension and anatomy (Gastropoda: Cocculinida: Bathysciadiidae).
Three new records of Bathysciadium pacificum Dall, 1908 from off Oregon and Washington extend the range of the species from Peru by ~7,300 km to the temperate northeastern Pacific. The preserved and relaxed animal shows that the mantle exten-sions are not sensory papillae, but mantle folds forming the periostracum rays on the shell. Examination of radula, mantle, and mantle cavity by scanning electron microscopy (SEM), including environmental SEM (ESEM) of the fluid-preserved animal, adds a novel dimension to the understanding of the anatomy of these rare deep-sea snails. ESEM is a suitable tool for the morphological investigations of rare natural history specimens. The monotypic genera Bathypelta Moskalev, 1971 and Bonus Moskalev, 1973 are re-synonymized under Bathy-sciadium Dautzenberg and H. Fischer, 1900. No mineralization of the radula was detected by SEM-Energy Dispersive Spec-troscopy (EDS/EDAX) mapping. more »« less
A new species of solenogaster (Mollusca, Aplacophora) from the Angola Basin is described: Macellomenia profundorum n. sp. The studied specimen was collected during the DIVA 1 expedition (Latitudinal Gradients of Deep-Sea BioDIVersity in the Atlantic Ocean). The description is based primarily on the sclerites and the internal anatomy (histological study). Macellomenia profundorum n. sp. is the first species of the family to be described from the southern hemisphere and constitutes its deepest record (5400 m deep). Even though only anterior anatomical characters are known, these and especially the radula and mantle sclerites are enough to justify that it is a new species. Amended diagnoses are also provided for the family and genus.
Abstract Owing to the importance of serpentinites for planetary geochemical and geodynamic processes, there has been much work discerning the origins of their parent rocks, including distinguishing between serpentinites derived from a subducting plate versus overlying mantle in exhumed subduction complexes. The island of New Caledonia (SW Pacific Ocean) provides a rare window into Cenozoic Pacific subduction processes. The island is unique in exposing both an exceptionally preserved high‐pressure, low‐temperature subduction complex and one of the largest supra‐subduction zone ophiolites in the world. Previous studies disagree on the origin of serpentinites in the subduction complex. In this study, we analyze 23 serpentinites from this complex for whole‐rock major and trace element geochemistry and stable isotope (δD, δ18O) compositions. Our data reveal two distinct groups of serpentinites: Group I samples in the northern portion of the complex are pervasively serpentinized, and exhibit enriched heavy rare earth element (REE) compositions and δ18O values between +6.7‰ and +10.2‰. In contrast, Group II serpentinites in the south preserve relict orthopyroxene and olivine, and show depleted trace element compositions and comparatively lower δ18O values between +5.1‰ and +8.0‰. We interpret Group I serpentinites to derive from downgoing plate mantle, whereas Group II serpentinites derive from overlying mantle wedge, exhibiting remarkable similarity to the REE geochemistry of the structurally overlying New Caledonia ophiolite. Our results establish the subduction complex in New Caledonia as an unusual natural record of the entrainment and exhumation of mantle from both the overlying mantle wedge and the downgoing plate in an oceanic subduction zone.
Moussallam, Yves; Rose-Koga, Estelle F; Aubaud, Cyril; Georgeais, Guillaume; Cartigny, Pierre; Koga, Kenneth T; Devidal, Jean-Luc; Michael, Peter J; Shimizu, Kei; Saal, Alberto E
(, Proceedings of the National Academy of Sciences)
Unraveling the origin(s) of carbon on Earth has remained challenging, not only because of the multiple isotopic fractionation episodes that may have occurred during planet formation processes but also because the end point of these processes, the current isotopic value of Earth’s deep carbon reservoirs remains poorly constrained. Here, we present carbon isotopic measurements on rare undegassed mid-ocean ridge basalts from the Pacific, Atlantic, and Arctic Oceans that have preserved the isotopic signature of their mantle source. We find that Earth’s present-day convecting upper mantle has variable δ13C value from ~−10 to −4‰, significantly different from the δ13C value of peridotitic diamonds and with the highest values being restricted to the Atlantic. Evidence for significant mantle heterogeneity contrasts with previous assumptions and its origin remains puzzling being uncorrelated with geochemical markers associated with either subduction and surficial recycling processes or lower mantle contributions. The data do not preclude other causes such as primordial mantle heterogeneity. We suggest that the δ13C value of the bulk silicate Earth may need to be revised.
Ozmen, Muslum Ozgur; Yavuz, Attila A.; Behnia, Rouzbeh
(, IEEE Conference on Communications and Network Security (CNS))
Authentication is vital for the Internet of Things (IoT) applications involving sensitive data (e.g., medical and financial systems). Digital signatures offer scalable authentication with non-repudiation and public verifiability, which are necessary for auditing and dispute resolution in such IoT applications. However, digital signatures have been shown to be highly costly for low-end IoT devices, especially when embedded devices (e.g., medical implants) must operate without a battery replacement for a long time. We propose an Energy-aware Signature for Embedded Medical devices (ESEM) that achieves near-optimal signer efficiency. ESEM signature generation does not require any costly operations (e.g., elliptic curve (EC) scalar multiplication/addition), but only a small constant-number of pseudo-random function calls, additions, and a single modular multiplication. ESEM has the smallest signature size among its EC-based counterparts with an identical private key size. We achieve this by eliminating the use of the ephemeral public key (i.e, commitment) in Schnorrtype signatures from the signing via a distributed construction at the verifier without interaction with the signer while permitting a constant-size public key. We proved that ESEM is secure (in random oracle model), and fully implemented it on an 8-bit AVR microcontroller that is commonly used in medical devices. Our experiments showed that ESEM achieves 8.4× higher energy efficiency over its closest counterpart while offering a smaller signature and code size. Hence, ESEM can be suitable for deployment on resource-limited embedded devices in IoT. We
A. Sanfilippo; C.Z. Liu; V. Salters; A. Mosconi; A. Zanetti; R. Tribuzio
(, Chemical geology)
N/A
(Ed.)
Long-lived radiogenic isotopes of abyssal peridotites, residues of MORB extraction, show that the asthenosphere is intrinsically heterogeneous, which is inherited from ancient melting events and crustal recycling during Earth's history. Yet, Mid Ocean Ridge Basalts (MORB) have a rather uniform average composition, suggesting that the variability of their mantle source is concealed during their ascent. Here we document that mantle heterogeneity is exceptionally well preserved in high permeability mantle conduits from the Lanzo South mantle massif, Western Italian Alps. Nd-Hf-Os isotopes of decametre-scale replacive bodies provide evidence for the existence of two generations of mantle channels. The first generation consists of dunites concordant to the main foliation of host peridotites. The replacive dunites include clinopyroxene with MORB-like incompatible element signature and initial (160 Ma) ƐNd and ƐHf ranging from +4 to +7 and from +10 to +15, respectively. The second generation, made up of pyroxene-poor harzburgites discordant to the main foliation, is geochemically depleted in incompatible elements and its clinopyroxene displays highly radiogenic Hf isotopes (initial ƐHf up to +202). The mantle channel heterogeneity is confirmed by Resingle bondOs isotopes and platinum-groups elements. The MORB-type dunites have high Pt, Pd and, locally, Re, and have 187Os/188Os ratios similar to the host peridotite (0.122–0.128). On the other hand, the depleted bodies have lower Pt, Pd and Re, and 187Os/188Os ratios ranging from those of host peridotites (0.124) to highly unradiogenic values (0.118) in the most refractory sample. The preserved heterogeneity in trace elements, PGE, and Nd-Hf-Os isotopes highlights infiltration of melts from a highly heterogeneous mantle, still partially preserved within these mantle bodies. If applied to present-day Mid Ocean Ridges, our model indicates that the isotopic variability of melts migrating through replacive mantle conduits is by far larger than magmas erupted on the seafloor, which implies that diverse mantle components are mainly delivered and homogenised above the crust-mantle boundary.
Geiger, Daniel L., and Thacker, Christine E. Bathysciadium pacificum Dall, 1908 from the bathyal of Oregon: range extension and anatomy (Gastropoda: Cocculinida: Bathysciadiidae).. Retrieved from https://par.nsf.gov/biblio/10457293. The Nautilus 137.2
Geiger, Daniel L., & Thacker, Christine E. Bathysciadium pacificum Dall, 1908 from the bathyal of Oregon: range extension and anatomy (Gastropoda: Cocculinida: Bathysciadiidae).. The Nautilus, 137 (2). Retrieved from https://par.nsf.gov/biblio/10457293.
Geiger, Daniel L., and Thacker, Christine E.
"Bathysciadium pacificum Dall, 1908 from the bathyal of Oregon: range extension and anatomy (Gastropoda: Cocculinida: Bathysciadiidae).". The Nautilus 137 (2). Country unknown/Code not available. https://par.nsf.gov/biblio/10457293.
@article{osti_10457293,
place = {Country unknown/Code not available},
title = {Bathysciadium pacificum Dall, 1908 from the bathyal of Oregon: range extension and anatomy (Gastropoda: Cocculinida: Bathysciadiidae).},
url = {https://par.nsf.gov/biblio/10457293},
abstractNote = {Three new records of Bathysciadium pacificum Dall, 1908 from off Oregon and Washington extend the range of the species from Peru by ~7,300 km to the temperate northeastern Pacific. The preserved and relaxed animal shows that the mantle exten-sions are not sensory papillae, but mantle folds forming the periostracum rays on the shell. Examination of radula, mantle, and mantle cavity by scanning electron microscopy (SEM), including environmental SEM (ESEM) of the fluid-preserved animal, adds a novel dimension to the understanding of the anatomy of these rare deep-sea snails. ESEM is a suitable tool for the morphological investigations of rare natural history specimens. The monotypic genera Bathypelta Moskalev, 1971 and Bonus Moskalev, 1973 are re-synonymized under Bathy-sciadium Dautzenberg and H. Fischer, 1900. No mineralization of the radula was detected by SEM-Energy Dispersive Spec-troscopy (EDS/EDAX) mapping.},
journal = {The Nautilus},
volume = {137},
number = {2},
author = {Geiger, Daniel L. and Thacker, Christine E.},
editor = {Leal, José}
}
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