Compendium of Current Total Ionizing Dose and Displacement Damage Results from NASA Goddard Space Flight Center and NASA Electronic Parts and Packaging Program

Total ionizing dose and displacement damage testing was performed to characterize and determine the suitability of candidate electronics for NASA space utilization. Devices tested include optoelectronics, digital, analog, linear bipolar devices, and hybrid devices. Displacement Damage, Optoelectronics, Proton Damage, Single Event Effects, and Total Ionizing Dose

The Archaeology of Yukon Ice Patches: New Artifacts, Observations, and Insights

Since 1997, more than 207 archaeological objects and 1700 faunal remains have been recovered from 43 melting ice patches in the southern Yukon. The artifacts range in age from a 9000-year-old (calendar) dart shaft to a 19th-century musket ball. This paper provides an update on Yukon ice patch research and summary data on select areas of research conducted since 2003. More than 200 radiocarbon dates have been run on ice patch archaeological and faunal materials, and these data allow us to observe and comment on apparent temporal trends. Analysis undertaken since 2003 has improved our understanding of the development and maintenance of hunting technologies, including dart shaft design, wood selection, and point styles. Of particular interest is the description of three different techniques for the construction of throwing darts and the observation of stability in the hunting technology employed in the study area over seven millennia. Radiocarbon chronologies indicate that this period of stability was followed by an abrupt technological replacement of the throwing dart by the bow and arrow after 1200 BP.Depuis 1997, plus de 350 objets archéologiques et de 1 700 restes fauniques ont été récupérés dans 43 névés en fusion dans le sud du Yukon. L’âge de ces artefacts varie, allant d’une tige de propulseur de 9 000 ans (années civiles) à une balle de mousquet du XIXe siècle. Dans cet article, nous faisons la mise à jour des données sommaires et des travaux de recherche effectués dans les névés de régions choisies du Yukon depuis 2003. Plus de 200 dates au carbone 14 ont été établies pour le matériel faunique et archéologique des névés. Ces données nous permettent d’observer les tendances temporales apparentes et de formuler des commentaires à leur sujet. Les analyses qui ont été effectuées depuis 2003 nous ont permis de mieux comprendre l’évolution et le maintien des techniques de chasse, notamment en matière de conception des tiges de propulseurs, de choix du bois et des types de pointes. La description de trois techniques différentes de fabrication de tirs au propulseur de même que l’observation de la stabilité entourant la technique de chasse employée au cours de la période visée par l’étude, soit plus de sept millénaires, revêtent un intérêt particulier. Les chronologies au carbone 14 indiquent que cette période de stabilité a été suivie d’un remplacement technique abrupt, qui est passé du tir au propulseur aux arcs et aux flèches après 1200 BP

Compendium of Current Total Ionizing Dose and Displacement Damage Results from NASA Goddard Space Flight Center and Selected NASA Electronic Parts and Packaging Program

Total ionizing dose and displacement damage testing was performed to characterize and determine the suitability of candidate electronics for NASA space utilization. Devices tested include optoelectronics, digital, analog, linear bipolar devices, and hybrid devices

The morphological disparity, ecological evolution and palaeobiogeography of Palaeozoic hyoliths

Hyolitha is a group of extinct invertebrates, the most dominant benthic animals within the Cambrian evolutionary fauna and forming a part of the Palaeozoic evolutionary fauna. Hyoliths are generally divided into two groups, Orthothecida and Hyolithida. They originated in the Terreneuvian and experienced a rapid diversification during the Cambrian Explosion but reached a diversity bottleneck during the Cambrian extinction (Sinsk Event). Hyoliths were characterised by low disparity beginning from the Ordovician and got extinct in the Permian. Factors that affected the evolutionary pattern of Palaeozoic hyoliths from the early domination period up to extinction are poorly known. Herein, we collected material on 148 Palaeozoic hyolith genera from around the world and documented their key morphological characters and distributions. Combined with the phylogenetic analysis based on a matrix of morphological characters, the nonmetric multidimensional scaling (NMDS) using the Paleontological Statistics Software Package, and palaeobiogeographical data, we intended to analyse the biodiversity changes during the evolutionary history of hyoliths and uncover the influence of morphological selectivity in different palaeoenvironments, from the Cambrian to the Permian. Our results showed that the Cambrian taxa occupied quite a different morphospace compared to that of the OrdovicianâPermian assemblages. The morphology of the early Cambrian hyoliths was mainly simple, comprising long conical weakly ornamented tubes. They radiated worldwide during the Cambrian âEpoch 2â, reaching high disparity and diversity, but faced a disadvantageous situation after the mid-Cambrian. The younger genera with strong ornamentation usually showed low diversity and provincialism during the Ordovician. The morphological shift from a simple conical tube morphology with weak ornamentation (orthothecids of the early Cambrian) to a complex morphology with distinct venter and dorsal pyramidal conch and strong ornamentation from the late Cambrian up to the Permian reflects ecological evolution of the hyoliths. This was accompanied by a change of their feeding habits from active deposit-feeding to passive suspension/filter feeding and change in conch configuration from rheophilic to non-rheophilic

When lingulid brachiopods became infaunal(?) – perspectives from the morphological and anatomical information

Morphology usually serves as an effective proxy for functional ecology, and the evaluation of morphological, anatomical, and ecological changes allows for a deeper understanding of the nature of diversification and macroevolution. Lingulid (Order Lingulida) brachiopods were diverse and abundant during the early Palaeozoic, but decreased in diversity over time, with only a few genera of linguloids and discinoids present in modern marine ecosystems, frequently referred to as âliving fossilsâ. The dynamics that drove this decline remain unclear and it has not been determined if there is an associated decline in morphological and ecological diversity. We applied geometric morphometrics to reconstruct global morphospace occupied by lingulid brachiopods through the Phanerozoic, with results showing that maximum morphospace occupation was reached in the Early Ordovician. At this time of peak diversity, linguloids with sub-rectangular shells already possessed several evolutionary features common to all modern infaunal forms such as the rearrangement of mantle canals and reduction of the pseudointerarea. The end-Ordovician mass extinction had a differential effect on linguloids, disproportionally wiping out those with rounded shells whilst forms with sub-rectangular shells survived both the end-Ordovician and the PermianâTriassic mass extinctions, with post-extinction faunas predominantly composed of infaunal forms. For discinoids, both morphospace occupation and epi-benthic life strategies remain consistent through the Phanerozoic. Analysis of the morphospace occupation of lingulids over time, taking into account their body size, anatomical features and ecological changes, suggests that the reduced morphological and ecological diversity observed in modern lingulid brachiopods reflects evolutionary contingency rather than deterministic processes

CAGI, the Critical Assessment of Genome Interpretation, establishes progress and prospects for computational genetic variant interpretation methods

Background: The Critical Assessment of Genome Interpretation (CAGI) aims to advance the state-of-the-art for computational prediction of genetic variant impact, particularly where relevant to disease. The five complete editions of the CAGI community experiment comprised 50 challenges, in which participants made blind predictions of phenotypes from genetic data, and these were evaluated by independent assessors. // Results: Performance was particularly strong for clinical pathogenic variants, including some difficult-to-diagnose cases, and extends to interpretation of cancer-related variants. Missense variant interpretation methods were able to estimate biochemical effects with increasing accuracy. Assessment of methods for regulatory variants and complex trait disease risk was less definitive and indicates performance potentially suitable for auxiliary use in the clinic. // Conclusions: Results show that while current methods are imperfect, they have major utility for research and clinical applications. Emerging methods and increasingly large, robust datasets for training and assessment promise further progress ahead

Moulting in the lobopodian Onychodictyon from the lower Cambrian of Greenland

A number of lobopodian taxa from the Cambrian display pairs of sclerotized plates symmetrically positioned along the dorsum of the animal, predominantly above the walking appendages. Most genera were described from complete body fossils exquisitely preserved in the famous Cambrian Lagerstätten, but lobopodian phosphatized plates are found worldwide as typical components of Cambrian small shelly fossil assemblages (SSF). Details regarding intraspecific and ontogenetic variation in lobopod plates are elusive, and the lack of details of ornamentation in Lagerstätte specimens does not minimize the problem. We document here an assemblage of well-preserved isolated plates of Onychodictyon sp. from the Lower Cambrian (Cambrian Series 2, Stage 4) of North Greenland. Two specimens exhibit perfectly conjoined plates from successive moults. Details of ornamentation and the outline and profile of the fixed plates are identical, but width and length of the underlying plate are 24% larger. These specimens boost the body of evidence that lobopodians moulted but also show that plate outline and ornamentation did not vary during ontogeny.This work has been supported by the Carlsberg Foundation (TPT) and Swedish Research Council (JSP)Origin and early evolution of major animal clades in the Cambrian Perio

Keeping a lid on it: muscle scars and the mystery of the Mobergellidae [Elektronisk resurs]

Mobergellans were one of the first Cambrian skeletal groups to be recognized yet have long remained one of the mostproblematic in terms of biological function and affinity. Characterized by a disc-shaped, phosphatic sclerite, the mostdistinctive character of the group is a prominent set of internal scars, interpreted as representing sites of former muscleattachment. Predominantly based on muscle scar distribution, mobergellans have been compared to brachiopods,bivalves and monoplacophorans; however, a recurring theory that the sclerites acted as an operculum remains untested.Rather than correlate the number of muscle scars between taxa, here we focus on the percentage of the inner surfaceshell area that the scars constitute. We investigate two mobergellan species, Mobergella holsti and Discinella micans,and compare the Cambrian taxa with the muscle scars of a variety of extant and fossil marine invertebrate taxa to testwhether the mobergellan muscle attachment area is compatible with an interpretation as operculum. The only skeletalelements in our study with a comparable muscle attachment percentage are gastropod opercula. Complemented withadditional morphological information, our analysis supports the theory that mobergellan sclerites acted as an operculumpresumably from a tube-living organism. The paucity of tubes co-occurring with mobergellan sclerites could beexplained by the transportation and sorting of detached opercula, while the corresponding tube remained attached tosubstrata in shallower water. The operculum perhaps performed a similar role to that seen in serpulid annelids and inneritid gastropods sealing the living chamber of the organism to avoid desiccation or for protection.</p

A new name for a classic Cambrian Swedish brachiopod, Tallatella undosa (Moberg)

The brachiopod originally described as Kuturgina undosa Moberg, 1892 from the early Cambrian (Cambrian Series 2, Stage 4) När Shale of Kalmarsund, Sweden, has experienced a long and turbulent history since the original description over 100 years ago. Uncertainties regarding key morphological characters have resulted in the species taxonomically hopping between genera until it wasrecently assigned to the poorly known genus Cryptotreta Pelman, 1977 and subsequently transferred to the problematic paterinate family Cryptotretidae. Despite members of this group representing the oldest brachiopods in the fossil record, they remain enigmatic, both taxonomically and phylogenetically. Theidentification of the brachiopod species from the När Shale as a cryptotretid means that this brachiopod was the first member of the family to be discovered, yet its systematic position is far from certain. Examination of type material in addition to supplementary material acquired from the Skäggenäs Peninsula, Sweden, has elucidated many of the previous ambiguous morphological characteristics of the species. The new morphological information acquired here has resulted in the erection of a new paterinate genus, Tallatella gen. nov., to accommodate the Swedish material previously described as Cryptotreta undosa.Origin and early evolution of major animal clades in the Cambrian Perio