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Sample records for 1-2 million years

  1. Environmental change explains cichlid adaptive radiation at Lake Malawi over the past 1.2 million years.

    PubMed

    Ivory, Sarah J; Blome, Margaret W; King, John W; McGlue, Michael M; Cole, Julia E; Cohen, Andrew S

    2016-10-18

    Long paleoecological records are critical for understanding evolutionary responses to environmental forcing and unparalleled tools for elucidating the mechanisms that lead to the development of regions of high biodiversity. We use a 1.2-My record from Lake Malawi, a textbook example of biological diversification, to document how climate and tectonics have driven ecosystem and evolutionary dynamics. Before ∼800 ka, Lake Malawi was much shallower than today, with higher frequency but much lower amplitude water-level and oxygenation changes. Since ∼800 ka, the lake has experienced much larger environmental fluctuations, best explained by a punctuated, tectonically driven rise in its outlet location and level. Following the reorganization of the basin, a change in the pacing of hydroclimate variability associated with the Mid-Pleistocene Transition resulted in hydrologic change dominated by precession rather than the high-latitude teleconnections recorded elsewhere. During this time, extended, deep lake phases have abruptly alternated with times of extreme aridity and ecosystem variability. Repeated crossings of hydroclimatic thresholds within the lake system were critical for establishing the rhythm of diversification, hybridization, and extinction that dominate the modern system. The chronology of these changes closely matches both the timing and pattern of phylogenetic history inferred independently for the lake's extraordinary array of cichlid fish species, suggesting a direct link between environmental and evolutionary dynamics.

  2. Diet and environment 1.2 million years ago revealed through analysis of dental calculus from Europe's oldest hominin at Sima del Elefante, Spain.

    PubMed

    Hardy, Karen; Radini, Anita; Buckley, Stephen; Blasco, Ruth; Copeland, Les; Burjachs, Francesc; Girbal, Josep; Yll, Riker; Carbonell, Eudald; Bermúdez de Castro, Jose María

    2017-02-01

    Sima del Elefante, Atapuerca, Spain contains one of the earliest hominin fragments yet known in Europe, dating to 1.2 Ma. Dental calculus from a hominin molar was removed, degraded and analysed to recover entrapped remains. Evidence for plant use at this time is very limited and this study has revealed the earliest direct evidence for foods consumed in the genus Homo. This comprises starchy carbohydrates from two plants, including a species of grass from the Triticeae or Bromideae tribe, meat and plant fibres. All food was eaten raw, and there is no evidence for processing of the starch granules which are intact and undamaged. Additional biographical detail includes fragments of non-edible wood found adjacent to an interproximal groove suggesting oral hygiene activities, while plant fibres may be linked to raw material processing. Environmental evidence comprises spores, insect fragments and conifer pollen grains which are consistent with a forested environment.

  3. Diet and environment 1.2 million years ago revealed through analysis of dental calculus from Europe's oldest hominin at Sima del Elefante, Spain

    NASA Astrophysics Data System (ADS)

    Hardy, Karen; Radini, Anita; Buckley, Stephen; Blasco, Ruth; Copeland, Les; Burjachs, Francesc; Girbal, Josep; Yll, Riker; Carbonell, Eudald; Bermúdez de Castro, Jose María

    2017-02-01

    Sima del Elefante, Atapuerca, Spain contains one of the earliest hominin fragments yet known in Europe, dating to 1.2 Ma. Dental calculus from a hominin molar was removed, degraded and analysed to recover entrapped remains. Evidence for plant use at this time is very limited and this study has revealed the earliest direct evidence for foods consumed in the genus Homo. This comprises starchy carbohydrates from two plants, including a species of grass from the Triticeae or Bromideae tribe, meat and plant fibres. All food was eaten raw, and there is no evidence for processing of the starch granules which are intact and undamaged. Additional biographical detail includes fragments of non-edible wood found adjacent to an interproximal groove suggesting oral hygiene activities, while plant fibres may be linked to raw material processing. Environmental evidence comprises spores, insect fragments and conifer pollen grains which are consistent with a forested environment.

  4. N zooming into the Mediterranean outflow fossil moat during the 1.2-1.8 million years period (Early-Pleistocene) - An approach by radiogenic and stable isotopes

    NASA Astrophysics Data System (ADS)

    Lebreiro, Susana M.; Antón, Laura; Reguera, M. Isabel; Fernández, Marta; Conde, Estefanía; Barrado, Ana I.; Yllera, Abel

    2015-12-01

    The fossil Alvarez Cabral erosive Moat contains hemipelagite, contourite and turbidite facies where oceanography changes in the Mediterranean outflow are archived over the 1.2-1.8 Myr time period. Here we used Pb and Sr radiogenic isotopes to trace water masses and sediment source changes, for the first time in twenty glacial-interglacial (G-I) cycles of the Early-Pleistocene interval, and the last Glacial Maximum through Holocene cycle (including the Younger Dryas and Heinrich Stadial-1). A mixing line of Pb isotopes gives reliable low radiogenic 208Pb/204Pb, 206Pb/204Pb, and 206Pb/207Pb typical of Mediterranean Outflow Water (MOW) in one end-member and the signature of high radiogenic isotopes of Atlantic Waters (AW) towards the second end-member. The 87Sr/86Sr isotopes also display two end-members of the mixing line between eolian transport/dust source (0.71) and fluvial transport/weathering source (0.73) previously proposed in the Gulf of Cadiz. Combination of Pb and Sr radiogenic isotopes with O and C stable isotopes of planktonic and benthic foraminifera, and the response of foraminifera benthos over the Early-Pleistocene interval, reveals a direct link between water masses circulation and shifts in G-I. We found a persistent cyclic pattern of MOW circulation and fluvial deposition during glaciations and AW and aeolian influence during interglaciations. On site U1386B/C, the upper-MOW was less ventilated but productive and with high flux of organic flux matter during glacials, while Atlantic Waters were better ventilated, enriched in O, but less productive during interglacials. We infer that shifts in ocean and atmospheric processes in the Gulf of Cadiz were strongly controlled by Earth's obliquity (41 kyr-cycle) and 35°NH insolation during the Early-Pleistocene. We propose a correlation in changes in phase-relationship between precession and obliquity. In general terms, physical properties of fine sediments (glacials) show lower NGR, low reflectance and

  5. Leaf metallome preserved over 50 million years.

    PubMed

    Edwards, N P; Manning, P L; Bergmann, U; Larson, P L; van Dongen, B E; Sellers, W I; Webb, S M; Sokaras, D; Alonso-Mori, R; Ignatyev, K; Barden, H E; van Veelen, A; Anné, J; Egerton, V M; Wogelius, R A

    2014-04-01

    Large-scale Synchrotron Rapid Scanning X-ray Fluorescence (SRS-XRF) elemental mapping and X-ray absorption spectroscopy are applied here to fossil leaf material from the 50 Mya Green River Formation (USA) in order to improve our understanding of the chemistry of fossilized plant remains. SRS-XRF of fossilized animals has previously shown that bioaccumulated trace metals and sulfur compounds may be preserved in their original distributions and these elements can also act as biomarkers for specific biosynthetic pathways. Similar spatially resolved chemical data for fossilized plants is sparsely represented in the literature despite the multitude of other chemical studies performed. Here, synchrotron data from multiple specimens consistently show that fossil leaves possess chemical inventories consisting of organometallic and organosulfur compounds that: (1) map discretely within the fossils, (2) resolve fine scale biological structures, and (3) are distinct from embedding sedimentary matrices. Additionally, the chemical distributions in fossil leaves are directly comparable to those of extant leaves. This evidence strongly suggests that a significant fraction of the chemical inventory of the examined fossil leaf material is derived from the living organisms and that original bioaccumulated elements have been preserved in situ for 50 million years. Chemical information of this kind has so far been unknown for fossilized plants and could for the first time allow the metallome of extinct flora to be studied.

  6. 40 Million Years of the Iceland Plume

    NASA Astrophysics Data System (ADS)

    Parnell-Turner, R. E.; White, N.; Henstock, T.; Maclennan, J.; Murton, B. J.; Jones, S. M.

    2011-12-01

    The V-shaped ridges, straddling the mid oceanic ridges to the North and South of Iceland, provide us with a linear record of transient mantle convective circulation. Surprisingly, we know little about the structure of these ridges: prior to this study, the most recent regional seismic reflection profiles were acquired in the 1960s. During the Summer of 2010, we acquired over 3,000 km of seismic reflection data across the oceanic basin South of Iceland. The cornerstones of this programme are two 1000 km flowlines, which traverse the basin from Greenland to the European margin. The geometry of young V-shaped ridges near to the oceanic spreading center has been imaged in fine detail; older ridges, otherwise obscured in gravity datasets by sediment cover, have been resolved for the first time. We have mapped the sediment-basement interface, transformed each profile onto an astronomical time scale, and removed the effects of long wavelength plate cooling. The resulting chronology of Icelandic plume activity provides an important temporal frame of reference for plume flux over the past 40 million years. The profiles also cross major contourite drift deposits, notably the Gardar, Bjorn and Eirik drifts. Fine-scale sedimentary features imaged here demonstrate distinct episodes of drift construction; by making simple assumptions about sedimentation rates, we can show that periods of drift formation correspond to periods of enhanced deep water circulation which is in turn moderated by plume activity. From a regional point of view, this transient behaviour manifests itself in several important ways. Within sedimentary basins fringing the North Atlantic, short lived regional uplift events periodically interrupt thermal subsidence from Eocene times to the present day. From a paleoceanographic perspective, there is good correlation between V-shaped ridge activity and changes in overflow of the ancient precursor to North Atlantic Deep Water. This complete history of the Iceland

  7. Tulelake, California: The last 3 million years

    USGS Publications Warehouse

    Adam, D.P.; Sarna-Wojcicki, A. M.; Rieck, H.J.; Bradbury, J.P.; Dean, W.E.; Forester, R.M.

    1989-01-01

    The Tulelake basin, formed by east-west extension and faulting during the past several million years, contains at least 550 m of lacustrine sediment. Interdisciplinary studies of a 334 m-long cored section from the town of Tulelake, California, near the center of the basin, document a 3-m.y. record of environmental changes. The core consists of a thick sequence of diatomaceous clayey, silty, and marly lacustrine sediments interbedded with numerous tephra layers. Paleomagnetic study puts the base of the core at about 3.0 Ma. Twelve widespread silicic tephra units provide correlations with other areas and complement age control provided by magnetostratigraphy; mafic and silicic tephra units erupted from local sources are also common in the core. Widespread tephra units include the Llao Rock pumice (=Tsoyawata, 7 ka), the Trego Hot Springs Bed (23 ka), and the Rockland (0.40 Ma), Lava Creek (0.62 Ma), and Rio Dell (1.5 Ma) ash beds, as well as several ash beds also found at Summer Lake, Oregon, and an ash bed originally recognized in DSDP hole 173 in the northeastern Pacific. Several tephra layers found in the core also occur in lacustrine beds exposed around the margins of the basin and elsewhere in the ancestral lacustrine system. Diatoms are present throughout the section. Pollen is present in most of the section, but some barren zones are found in the interval between 50 and 140 m; the greatest change in behavior of the pollen record takes place just above the top of the Olduvai Normal-Polarity Subchronozone. Ostracodes are present only in high-carbonate (>10% CaCO3) intervals. Evolutionary changes are found in the diatom and ostracode records. Bulk geochemical analyses show significant changes in elemental composition of the sediment through time. ?? 1989.

  8. Evolution of global temperature over the past two million years.

    PubMed

    Snyder, Carolyn W

    2016-10-13

    Reconstructions of Earth's past climate strongly influence our understanding of the dynamics and sensitivity of the climate system. Yet global temperature has been reconstructed for only a few isolated windows of time, and continuous reconstructions across glacial cycles remain elusive. Here I present a spatially weighted proxy reconstruction of global temperature over the past 2 million years estimated from a multi-proxy database of over 20,000 sea surface temperature point reconstructions. Global temperature gradually cooled until roughly 1.2 million years ago and cooling then stalled until the present. The cooling trend probably stalled before the beginning of the mid-Pleistocene transition, and pre-dated the increase in the maximum size of ice sheets around 0.9 million years ago. Thus, global cooling may have been a pre-condition for, but probably is not the sole causal mechanism of, the shift to quasi-100,000-year glacial cycles at the mid-Pleistocene transition. Over the past 800,000 years, polar amplification (the amplification of temperature change at the poles relative to global temperature change) has been stable over time, and global temperature and atmospheric greenhouse gas concentrations have been closely coupled across glacial cycles. A comparison of the new temperature reconstruction with radiative forcing from greenhouse gases estimates an Earth system sensitivity of 9 degrees Celsius (range 7 to 13 degrees Celsius, 95 per cent credible interval) change in global average surface temperature per doubling of atmospheric carbon dioxide over millennium timescales. This result suggests that stabilization at today's greenhouse gas levels may already commit Earth to an eventual total warming of 5 degrees Celsius (range 3 to 7 degrees Celsius, 95 per cent credible interval) over the next few millennia as ice sheets, vegetation and atmospheric dust continue to respond to global warming.

  9. Evolution of global temperature over the past two million years

    NASA Astrophysics Data System (ADS)

    Snyder, Carolyn W.

    2016-10-01

    Reconstructions of Earth’s past climate strongly influence our understanding of the dynamics and sensitivity of the climate system. Yet global temperature has been reconstructed for only a few isolated windows of time, and continuous reconstructions across glacial cycles remain elusive. Here I present a spatially weighted proxy reconstruction of global temperature over the past 2 million years estimated from a multi-proxy database of over 20,000 sea surface temperature point reconstructions. Global temperature gradually cooled until roughly 1.2 million years ago and cooling then stalled until the present. The cooling trend probably stalled before the beginning of the mid-Pleistocene transition, and pre-dated the increase in the maximum size of ice sheets around 0.9 million years ago. Thus, global cooling may have been a pre-condition for, but probably is not the sole causal mechanism of, the shift to quasi-100,000-year glacial cycles at the mid-Pleistocene transition. Over the past 800,000 years, polar amplification (the amplification of temperature change at the poles relative to global temperature change) has been stable over time, and global temperature and atmospheric greenhouse gas concentrations have been closely coupled across glacial cycles. A comparison of the new temperature reconstruction with radiative forcing from greenhouse gases estimates an Earth system sensitivity of 9 degrees Celsius (range 7 to 13 degrees Celsius, 95 per cent credible interval) change in global average surface temperature per doubling of atmospheric carbon dioxide over millennium timescales. This result suggests that stabilization at today’s greenhouse gas levels may already commit Earth to an eventual total warming of 5 degrees Celsius (range 3 to 7 degrees Celsius, 95 per cent credible interval) over the next few millennia as ice sheets, vegetation and atmospheric dust continue to respond to global warming.

  10. 234U/238U Disequilibrium along stylolitic discontinuities in deep Mesozoic limestone formations of the Eastern Paris basin: evidence for discrete uranium mobility over the last 1-2 million years

    NASA Astrophysics Data System (ADS)

    Deschamps, P.; Hillaire-Marcel, C. E.; Michelot, J.-L.; Doucelance, R.; Ghaleb, B.; Buschaert, S.

    The (234U/238) equilibrium state of borehole core samples from the deep, low-permeability limestone formations surrounding the target argilite layer of the Meuse/Haute-Marne experimental site of the French agency for nuclear waste management -ANDRA- (Agence nationale pour la gestion des déchets radioactifs) was examined to improve understanding of naturally occurring radionuclide behaviour in such geological settings. Highly precise, accurate MC-ICP-MS measurements of the (234U/238U) activity ratio show that limestone samples characterised by pressure dissolution structures (stylolites or dissolution seams) display systematic (234U/238U) disequilibria, while the pristine carbonate samples remain in the secular equilibrium state. The systematic feature is observed throughout the zones marked by pressure dissolution structures: (i) the material within the seams shows a deficit of 234U over 238U ((234U/238U) down to 0.80) and (ii) the surrounding carbonate matrix is characterised by an activity ratio greater than unity (up to 1.05). These results highlight a centimetric-scale uranium remobilisation in the limestone formations along these sub-horizontal seams. Although their nature and modalities are not fully understood, the driving processes responsible for these disequilibria were active during the last 1-2 Ma.

  11. Glaciation in southern Argentina more than two million years ago.

    PubMed

    Mercer, J H

    1969-05-16

    In southern Argentina till beds interbedded with lava flows were deposited by ice that extended at least 40 kilometers east of the present crest of the cordillera. The flow covering the oldest till bed is 3.2 +/- 1 million years old. The flow that constitutes the present surface and covers the youngest till bed, is 1.7 +/- 0.5 million years old.

  12. Flood basalt volcanism during the past 250 million years.

    PubMed

    Rampino, M R; Stothers, R B

    1988-08-05

    A chronology of the initiation dates of major continental flood basalt volcanism is established from published potassium-argon (K-Ar) and argon-argon (Ar-Ar) ages of basaltic rocks and related basic intrusions. The dating is therefore independent of the biostratigraphic and paleomagnetic time scales. Estimated errors of the initation dates of the volcanic episodes determined from the distributions of the radiometric ages are, approximately, plus or minus 4 percent. There were 11 distinct episodes during the past 250 million years. Sometimes appearing in pairs, the episodes have occurred quasi-periodically with a mean cycle time of 32 +/- 1 (estimated, error of the mean) million years. The initiation dates of the episodes are close to the estimated dates of mass extinctions of marine organisms. Showers of impacting comets may be the cause.

  13. Flood basalt volcanism during the past 250 million years

    NASA Technical Reports Server (NTRS)

    Rampino, Michael R.; Stothers, Richard B.

    1988-01-01

    A chronology of the initiation dates of major continental flood basalt volcanism is established from published potassium-argon (K-Ar) and argon-argon (Ar-Ar) ages of basaltic rocks and related basic intrusions. The dating is therefore independent of the biostratigraphic and paleomagnetic time scales. Estimated errors of the initiation dates of the volcanic episodes determined from the distributions of the radiometric ages are, approximately, + or - 4 percent. There were 11 distinct episodes during the past 250 million years. Sometimes appearing in pairs, the episodes have occurred quasi-periodically with a mean cycle time of 32 + or - 1 (estimated error of the mean) million years. The initiation dates of the episodes are close to the estimated dates of mass extinctions of marine organisms. Showers of impacting comets may be the cause.

  14. The 13 million year Cenozoic pulse of the Earth

    NASA Astrophysics Data System (ADS)

    Chen, Jiasheng; Kravchinsky, Vadim A.; Liu, Xiuming

    2015-12-01

    The geomagnetic polarity reversal rate changes radically from very low to extremely high. Such process indicates fundamental changes in the Earth's core reorganization and core-mantle boundary heat flow fluctuations. However, we still do not know how critical such changes are to surface geology and climate processes. Our analysis of the geomagnetic reversal frequency, oxygen isotope record, and tectonic plate subduction rate, which are indicators of the changes in the heat flux at the core mantle boundary, climate and plate tectonic activity, shows that all these changes indicate similar rhythms on million years' timescale in the Cenozoic Era occurring with the common fundamental periodicity of ∼13 Myr during most of the time. The periodicity is disrupted only during the last 20 Myr. Such periodic behavior suggests that large scale climate and tectonic changes at the Earth's surface are closely connected with the million year timescale cyclical reorganization of the Earth's interior.

  15. 15 million preterm births annually: what has changed this year?

    PubMed Central

    2012-01-01

    Each year, more than 1 in 10 of the world’s babies are born preterm, resulting in 15 million babies born too soon. World Prematurity Day, November 17, is a global effort to raise awareness about prematurity. This past year, there has been increased awareness of the problem, through new data and evidence, global partnership and country champions. Actions to improve care would save hundreds of thousands of babies born too soon from death and disability. Accelerated prevention requires urgent research breakthroughs. PMID:23148557

  16. Osteopathology in Rhinocerotidae from 50 Million Years to the Present

    PubMed Central

    Stilson, Kelsey T.; Hopkins, Samantha S. B.; Davis, Edward Byrd

    2016-01-01

    Individual elements of many extinct and extant North American rhinocerotids display osteopathologies, particularly exostoses, abnormal textures, and joint margin porosity, that are commonly associated with localized bone trauma. When we evaluated six extinct rhinocerotid species spanning 50 million years (Ma), we found the incidence of osteopathology increases from 28% of all elements of Eocene Hyrachyus eximius to 65–80% of all elements in more derived species. The only extant species in this study, Diceros bicornis, displayed less osteopathologies (50%) than the more derived extinct taxa. To get a finer-grained picture, we scored each fossil for seven pathological indicators on a scale of 1–4. We estimated the average mass of each taxon using M1-3 length and compared mass to average pathological score for each category. We found that with increasing mass, osteopathology also significantly increases. We then ran a phylogenetically-controlled regression analysis using a time-calibrated phylogeny of our study taxa. Mass estimates were found to significantly covary with abnormal foramen shape and abnormal bone textures. This pattern in osteopathological expression may reflect a part of the complex system of adaptations in the Rhinocerotidae over millions of years, where increased mass, cursoriality, and/or increased life span are selected for, to the detriment of long-term bone health. This work has important implications for the future health of hoofed animals and humans alike. PMID:26840633

  17. Bilaterian burrows and grazing behavior at >585 million years ago.

    PubMed

    Pecoits, Ernesto; Konhauser, Kurt O; Aubet, Natalie R; Heaman, Larry M; Veroslavsky, Gerardo; Stern, Richard A; Gingras, Murray K

    2012-06-29

    Based on molecular clocks and biomarker studies, it is possible that bilaterian life emerged early in the Ediacaran, but at present, no fossils or trace fossils from this time have been reported. Here we report the discovery of the oldest bilaterian burrows in shallow-water glaciomarine sediments from the Tacuarí Formation, Uruguay. Uranium-lead dating of zircons in cross-cutting granite dykes constrains the age of these burrows to be at least 585 million years old. Their features indicate infaunal grazing activity by early eumetazoans. Active backfill within the burrow, an ability to wander upward and downward to exploit shallowly situated sedimentary laminae, and sinuous meandering suggest advanced behavioral adaptations. These findings unite the paleontological and molecular data pertaining to the evolution of bilaterians, and link bilaterian origins to the environmental changes that took place during the Neoproterozoic glaciations.

  18. Atmospheric Oxygen Variation Over the Last 100 Million Years

    NASA Astrophysics Data System (ADS)

    Watson, A. J.; Mills, B.; Daines, S. J.; Lenton, T. M.; Belcher, C.

    2014-12-01

    There is no agreement over how atmospheric oxygen has varied over recent Earth history. Our knowledge of past O2 concentrations relies on biogeochemical modelling, constrained by geochemical data and proxies. There are however few direct indicators of oxygen concentrations, though the presence of fossil charcoal indicates that levels have not strayed outside the "fire window", say below 16% or above 35%, during the last hundred million years. Different model predictions encompass both decreasing and increasing trends over this period however. These predictions are sensitive to weathering of continental rocks, which provide a sink for O2, but also a supply of phosphorus and sediment to the ocean, both of which increase carbon burial and thereby provide an oxygen source. Here we update our COPSE model with a more detailed treatment than hitherto, incorporating new input data, seafloor weathering processes, and different compositions and weatherability of granites and basalts. Our model suggests a broadly declining O2 trend over the late Mesozoic to present. An alternative forcing uses the phosphorus deposition curve of Follmi (1995), which is constructed from P measurements in ocean cores, and indicates P fluxes to the oceans that have varied over time by two orders of magnitude. Used to drive the model this also results in a declining long-term trend for atmospheric O2 over the last hundred million years, but with dramatic shorter-term variations superposed on the trend. These however stay (just) within the "fire window" for oxygen concentrations, and can be tentatively related to the evolution of fire adaptations in plants.

  19. Possible shell disease in 100 million-year-old crabs.

    PubMed

    Klompmaker, Adiël A; Chistoserdov, Andrei Y; Felder, Darryl L

    2016-05-03

    Modern organisms exhibit evidence of many diseases, but recognizing such evidence in fossils remains difficult, thus hampering the study of the evolution of disease. We report on 2 molts of the goniodromitid crabs Distefania incerta and Goniodromites laevis from the mid-Cretaceous (late Albian) of Spain, with both species exhibiting damage to the dorsal carapace in otherwise well-preserved specimens. The subcircular to quadratical holes, found in <0.2% of the specimens, resemble damage caused by bacterial infections on the cuticle of modern decapods in terms of size and shape. Abiotic damage, predation, and encrustation followed by damage to the shell provide less satisfactory explanations, although these agents cannot be completely excluded from a role in shell disease etiology. We hypothesize that the observed fossil lesions are caused primarily by bacterial disease that started prior to molting, with or without other agents of initiation. If correct, this is the only known example of such bacterial infections in decapod crustaceans from the fossil record thus far, pushing back the evolutionary history of this type of shell disease by ~100 million years.

  20. Hominins on Flores, Indonesia, by one million years ago.

    PubMed

    Brumm, Adam; Jensen, Gitte M; van den Bergh, Gert D; Morwood, Michael J; Kurniawan, Iwan; Aziz, Fachroel; Storey, Michael

    2010-04-01

    Previous excavations at Mata Menge and Boa Lesa in the Soa Basin of Flores, Indonesia, recovered stone artefacts in association with fossilized remains of the large-bodied Stegodon florensis florensis. Zircon fission-track ages from these sites indicated that hominins had colonized the island by 0.88 +/- 0.07 million years (Myr) ago. Here we describe the contents, context and age of Wolo Sege, a recently discovered archaeological site in the Soa Basin that has in situ stone artefacts and that lies stratigraphically below Mata Menge and immediately above the basement breccias of the basin. We show using (40)Ar/(39)Ar dating that an ignimbrite overlying the artefact layers at Wolo Sege was erupted 1.02 +/- 0.02 Myr ago, providing a new minimum age for hominins on Flores. This predates the disappearance from the Soa Basin of 'pygmy' Stegodon sondaari and Geochelone spp. (giant tortoise), as evident at the nearby site of Tangi Talo, which has been dated to 0.90 +/- 0.07 Myr ago. It now seems that this extirpation or possible extinction event and the associated faunal turnover were the result of natural processes rather than the arrival of hominins. It also appears that the volcanic and fluvio-lacustrine deposits infilling the Soa Basin may not be old enough to register the initial arrival of hominins on the island.

  1. Anthropogenic carbon release rate unprecedented during past 66 million years

    NASA Astrophysics Data System (ADS)

    Zeebe, R. E.; Ridgwell, A.; Zachos, J. C.

    2015-12-01

    Carbon release rates from anthropogenic sources have reached a record high of about 10 Pg C/y in 2013. However, due to uncertainties in the strength of climate system feedbacks, the full impact of the rapid carbon release on the Earth system is difficult to predict with confidence. Geologic analogues from past transient climate changes could provide invaluable constraints but only if the associated carbon release rates can be reliably reconstructed. We present a new technique - based on combined data-model analysis - to extract rates of change from the geological record, without the need for a stratigraphic age model. Given currently available records, we then show that the present anthropogenic carbon release rate is unprecedented during the Cenozoic (past 66 million years) by at least an order of magnitude. Our results have important implications for our ability to use past analogues to predict future changes, including constraints on climate sensitivity, ocean acidification, and impacts on marine and terrestrial ecosystems. For example, the fact that we have effectively entered an era of 'no analogue' state presents fundamental challenges to constraining forward modeling. Furthermore, future ecosystem disruptions will likely exceed the relatively limited extinctions observed during climate aberrations throughout the Cenozoic.

  2. Cobb Hotspot Volcanism Prior to 7 Million Years ago

    NASA Astrophysics Data System (ADS)

    Keller, R.; Fisk, M.; Duncan, R.; Rowe, M.; Russo, C.; Dziak, R.

    2003-12-01

    From where the Cobb hotspot currently resides beneath Axial Seamount on the Juan de Fuca Ridge, a discontinuous trail of seamounts of increasing age extends 1800 km to the northwest, all the way to the Alaskan Trench off of the southern tip of Kodiak Island. These seamounts record the evolution of mantle melting and volcanism at the Cobb hotspot over the past 30+ million years, including how the approach of the Juan de Fuca Ridge from the east affected the hotspot. We conducted multibeam mapping and stratigraphically-controlled rock sampling of several of the seamounts created by the Cobb hotspot up until 7 Ma. Using the Alvin submersible to do depth transects for geological observations and rock sampling allowed us to establish the volcanic style and setting represented by each sample, and to avoid the thick ferro-manganese oxide coatings and abundant ice-rafted debris common in the Gulf of Alaska. Our goal is to understand the volcanic histories and morphologies of these seamounts with an eye to how volcanism at the hotspot was affected by the approaching ridge. Our targeted seamounts included, from SE to NW, Warwick ( ˜7 Ma on 9 Ma crust), Murray ( ˜28 Ma on 39 Ma crust), Patton ( ˜30 Ma on 42 Ma crust), and Marchand (30+? Ma on 43 Ma crust). Marchand Seamount, though small compared to the others, appears to be the oldest unsubducted volcanic product of the Cobb hotspot. So far, we have XRF data for our samples, and argon dating and trace element analyses are underway. Warwick Seamount yielded only tholeiitic basalts, while most of the samples from the other seamounts are evolved alkalic rocks. Murray samples are entirely alkalic, being dominantly trachytes and trachydacites, with a few mugearites. Rocks from Patton are mainly hawaiites and mugearites, with rare tholeiitic to transitional basalts and a single trachyte. Marchand samples are trachydacites and trachytes similar to the differentiated Patton and Murray samples. Basement drilling at ODP Hole 887D

  3. Once in a Million Years: Teaching Geologic Time

    ERIC Educational Resources Information Center

    Lewis, Susan E.; Lampe, Kristen A.; Lloyd, Andrew J.

    2005-01-01

    The authors advocate that students frequently lack fundamental numerical literacy on the order of millions or billions, and that this comprehension is critical to grasping key evolutionary concepts related to the geologic time scale, the origin and diversification of life on earth, and other concepts such as the national debt, human population…

  4. A 365-Million-Year-Old Freshwater Community Reveals Morphological and Ecological Stasis in Branchiopod Crustaceans.

    PubMed

    Gueriau, Pierre; Rabet, Nicolas; Clément, Gaël; Lagebro, Linda; Vannier, Jean; Briggs, Derek E G; Charbonnier, Sylvain; Olive, Sébastien; Béthoux, Olivier

    2016-02-08

    Branchiopod crustaceans are represented by fairy, tadpole, and clam shrimps (Anostraca, Notostraca, Laevicaudata, Spinicaudata), which typically inhabit temporary freshwater bodies, and water fleas (Cladoceromorpha), which live in all kinds of freshwater and occasionally marine environments [1, 2]. The earliest branchiopods occur in the Cambrian, where they are represented by complete body fossils from Sweden such as Rehbachiella kinnekullensis [3] and isolated mandibles preserved as small carbonaceous fossils [4-6] from Canada. The earliest known continental branchiopods are associated with hot spring environments [7] represented by the Early Devonian Rhynie Chert of Scotland (410 million years ago) and include possible stem-group or crown-group Anostraca, Notostraca, and clam shrimps or Cladoceromorpha [8-10], which differ morphologically from their modern counterparts [1, 2, 11]. Here we report the discovery of an ephemeral pool branchiopod community from the 365-million-year-old Strud locality of Belgium. It is characterized by new anostracans and spinicaudatans, closely resembling extant species, and the earliest notostracan, Strudops goldenbergi [12]. These branchiopods released resting eggs into the sediment in a manner similar to their modern representatives [1, 2]. We infer that this reproductive strategy was critical to overcoming environmental constraints such as seasonal desiccation imposed by living on land. The pioneer colonization of ephemeral freshwater pools by branchiopods in the Devonian was followed by remarkable ecological and morphological stasis that persists to the present day.

  5. THE FIRST KINEMATIC DETERMINATION OF MILLION-YEAR PRECESSION PERIOD OF ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Gong, B. P.; Li, Y. P.; Zhang, H. C.

    2011-06-20

    Short precession periods like the 164 day period of SS433 can be well determined by observations of timescales longer or much longer than the precession period. However, this does not work for sources with precession periods of millions of years. This Letter utilizes the particular morphologies of X-shaped sources, so that the three-dimensional kinematics of lobes can be obtained. Thus, for the first time, the million-year precession period of X-shaped sources by an observer on the Earth can be determined elegantly: 6.1 {+-} 1.5 Myr, 1.8 {+-} 0.5 Myr, and 3.2 {+-} 1.2 Myr for 3C52, 3C223.1, and 4C12.03, respectively. The result naturally explains the asymmetry displayed in the morphology of these sources, and the effect of propagation time on the diversity of morphologies is well demonstrated. The precession period may originate from long-term effects of a binary supermassive black hole system, which is a potential source of gravitational wave radiation.

  6. Evidence for life on Earth more than 3850 million years ago.

    PubMed

    Holland, H D

    1997-01-03

    A recent study by Mojzsis et al., (Nature 384, 55, 1996) found evidence of life in rocks in Greenland estimated by new isotopic data to be more than 3800 million years old. The author examines this study in relation to studies conducted on rocks between 3250 and 3800 million years old and presents reasons to agree and disagree with the interpretation of data.

  7. Stature, body mass, and brain size: a two-million-year odyssey.

    PubMed

    Gallagher, Andrew

    2013-12-01

    Physical size has been critical in the evolutionary success of the genus Homo over the past 2.4 million-years. An acceleration in the expansion of savannah grasslands in Africa from 1.6Ma to 1.2Ma witnessed concomitant increases in physical stature (150-170cm), weight (50-70kg), and brain size (750-900cm(3)). With the onset of 100,000year Middle Pleistocene glacial cycles ("ice ages") some 780,000years ago, large-bodied Homo groups had reached modern size and had successfully dispersed from equatorial Africa, Central, and Southeast Asia to high-latitude localities in Atlantic Europe and North East Asia. While there is support for incursions of multiple Homo lineages to West Asia and Continental Europe at this time, data does not favour a persistence of Homo erectus beyond ∼400,000years ago in Africa, west and Central Asia, and Europe. Novel Middle Pleistocene Homo forms (780,000-400,000years) may not have been substantially taller (150-170cm) than earlier Homo (1.6Ma-800,000years), yet brain size exceeded 1000cm(3) and body mass approached 80kg in some males. Later Pleistocene Homo (400,000-138,000years) were 'massive' in their height (160-190cm) and mass (70-90kg) and consistently exceed recent humans. Relative brain size exceeds earlier Homo, yet is substantially lower than in final glacial H. sapiens and Homo neanderthalensis. A final leap in absolute and relative brain size in Homo (300,000-138,000years) occurred independent of any observed increase in body mass and implies a different selective mediator to that operating on brain size increases observed in earlier Homo.

  8. New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya.

    PubMed

    Leakey, M G; Feibel, C S; McDougall, I; Walker, A

    1995-08-17

    Nine hominid dental, cranial and postcranial specimens from Kanapoi, Kenya, and 12 specimens from Allia Bay, Kenya, are described here as a new species of Australopithecus dating from between about 3.9 million and 4.2 million years ago. The mosaic of primitive and derived features shows this species to be a possible ancestor to Australopithecus afarensis and suggests that Ardipithecus ramidus is a sister species to this and all later hominids. A tibia establishes that hominids were bipedal at least half a million years before the previous earliest evidence showed.

  9. Formation of the Grand Canyon 5 to 6 million years ago through integration of older palaeocanyons

    NASA Astrophysics Data System (ADS)

    Karlstrom, Karl E.; Lee, John P.; Kelley, Shari A.; Crow, Ryan S.; Crossey, Laura J.; Young, Richard A.; Lazear, Greg; Beard, L. Sue; Ricketts, Jason W.; Fox, Matthew; Shuster, David L.

    2014-03-01

    The timing of formation of the Grand Canyon, USA, is vigorously debated. In one view, most of the canyon was carved by the Colorado River relatively recently, in the past 5-6 million years. Alternatively, the Grand Canyon could have been cut by precursor rivers in the same location and to within about 200 m of its modern depth as early as 70-55 million years ago. Here we investigate the time of formation of four out of five segments of the Grand Canyon, using apatite fission-track dating, track-length measurements and apatite helium dating: if any segment is young, the old canyon hypothesis is falsified. We reconstruct the thermal histories of samples taken from the modern canyon base and the adjacent canyon rim 1,500 m above, to constrain when the rocks cooled as a result of canyon incision. We find that two of the three middle segments, the Hurricane segment and the Eastern Grand Canyon, formed between 70 and 50 million years ago and between 25 and 15 million years ago, respectively. However, the two end segments, the Marble Canyon and the Westernmost Grand Canyon, are both young and were carved in the past 5-6 million years. Thus, although parts of the canyon are old, we conclude that the integration of the Colorado River through older palaeocanyons carved the Grand Canyon, beginning 5-6 million years ago.

  10. Role of seasonality in the evolution of climate during the last 100 million years

    NASA Technical Reports Server (NTRS)

    Crowley, T. J.; Short, D. A.; North, G. R.; Mengel, J. G.

    1986-01-01

    A simple climate model has been used to calculate the effect of past changes in the land-sea distribution on the seasonal cycle of temperatures during the last 100 million years. Modeled summer temperature decreased over Greenland by more than 10 C and over Antarctica by 5 to 8 C. For the last 80 million years, this thermal response is comparable in magnitude to estimated atmospheric carbon dioxide effects. Analysis of paleontological data provides some support for the proposed hypothesis that large changes due to seasonality may have sometimes resulted in an ice-free state due to high summer temperatures rather than year-round warmth. Such 'cool' nonglacials may have prevailed for as much as one-third of the last 100 million years.

  11. The Frequency and Predicted Consequences of Cosmic Impacts in the Last 65 Million Years

    NASA Astrophysics Data System (ADS)

    Paine, Michael; Peiser, Benny

    2004-06-01

    Sixty five million years ago a huge asteroid collided with the Earth and ended the long reign of the dinosaurs. In the aftermath of this catastrophic event, the mammals arose and eventually mankind came to dominate the surface of the planet. The Earth, however, has not been free from severe impacts since the time of the dinosaur killer. We examine the likely frequency of major impact events over the past 65 million years, the evidence for these impacts and the predicted consequences of various types of impacts. It is evident that the mammals had to survive frequent severe disruptions to the global climate, and it is likely that over the past 5 million years hominids were faced with several catastrophic global events. Smaller but strategically located impact events could bring down our civilisation if they occurred today. Mankind has recently developed the expertise to predict and mitigate future impacts, but political and financial support are lacking.

  12. A dynamic marine calcium cycle during the past 28 million years

    USGS Publications Warehouse

    Griffith, E.M.; Paytan, A.; Caldeira, K.; Bullen, T.D.; Thomas, E.

    2008-01-01

    Multiple lines of evidence have shown that the isotopic composition and concentration of calcium in seawater have changed over the past 28 million years. A high-resolution, continuous seawater calcium isotope ratio curve from marine (pelagic) barite reveals distinct features in the evolution of the seawater calcium isotopic ratio suggesting changes in seawater calcium concentrations. The most pronounced increase in the ??44/40Ca value of seawater (of 0.3 per mil) occurred over roughly 4 million years following a period of low values around 13 million years ago. The major change in marine calcium corresponds to a climatic transition and global change in the carbon cycle and suggests a reorganization of the global biogeochemical system.

  13. Woody cover and hominin environments in the past 6million years

    NASA Astrophysics Data System (ADS)

    Cerling, Thure E.; Wynn, Jonathan G.; Andanje, Samuel A.; Bird, Michael I.; Korir, David Kimutai; Levin, Naomi E.; Mace, William; Macharia, Anthony N.; Quade, Jay; Remien, Christopher H.

    2011-08-01

    The role of African savannahs in the evolution of early hominins has been debated for nearly a century. Resolution of this issue has been hindered by difficulty in quantifying the fraction of woody cover in the fossil record. Here we show that the fraction of woody cover in tropical ecosystems can be quantified using stable carbon isotopes in soils. Furthermore, we use fossil soils from hominin sites in the Awash and Omo-Turkana basins in eastern Africa to reconstruct the fraction of woody cover since the Late Miocene epoch (about 7 million years ago). 13C/12C ratio data from 1,300 palaeosols at or adjacent to hominin sites dating to at least 6million years ago show that woody cover was predominantly less than ~40% at most sites. These data point to the prevalence of open environments at the majority of hominin fossil sites in eastern Africa over the past 6million years.

  14. Discoidal impressions and trace-like fossils more than 1200 million years old.

    PubMed

    Rasmussen, Birger; Bengtson, Stefan; Fletcher, Ian R; McNaughton, Neal J

    2002-05-10

    The Stirling Range Formation of southwestern Australia contains discoidal impressions and trace-like fossils in tidal sandstones. The various disks have previously been linked to the Ediacaran biota, younger than 600 million years old. From this unit, we report U-Th-Pb geochronology of detrital zircon and monazite, as well as low-grade metamorphic monazite, constraining the depositional age to between 2016 +/- 6 and 1215 +/- 20 million years old. Although nonbiological origins for the discoidal impressions cannot be completely discounted, the structures resembling trace fossils clearly have a biological origin and suggest the presence of vermiform, mucus-producing, motile organisms.

  15. [The future population of Mexico. 123 million by the year 2010].

    PubMed

    Madrigal Hinojosa, R

    1988-01-01

    Recent data on fertility in Mexico have allowed identification of the most likely of 2 alternative population projections through the year 2010. The projection assumes an increase in life expectancy for men and women respectively from 64.08 and 70.47 in 1980-85 and 77.00 in 2005-10. The migration assumption is that there will be a net loss of 529,274 Mexicans every 5 years. The total fertility rate is expected to decline from to 2.7. The total population was projected at 82.8 million in 1988, 104.0 million at the end of the century, and 123.2 million in 2010. The 0-14 age group will decline from 44.23% of the population in 1980 and 40.33% in 1985 to 31.41% in 2000 and 29.50% in 2010. The proportion aged 15-64 will increase from 52.45% in 1980 and 56.22% in 1985 to 63.96% in 2000 and 64 75% in 2010. The proportion of the population in localities with under 2500 inhabitants is expected to remain stable at about 24.3 million persons. Mexico City, Guadalajara, Monterrey, and Puebla will have a combined population of 35 million by the year 2000. In 2010, the Federal District and the State of Mexico which includes Mexico City are expected to contain 29.3% of the total population. The projected population increase over the next 22 years is 40.4 million, 16% greater than the national population in 1960. The implications for providing food and consumer goods, and especially for improving the quality of life are serious. The relative demand for primary and secondary education and for maternal-child health care will decline, but the demand for jobs and for family planning services will increase as the proportion of the population in the economically active age groups increases.

  16. Southern Ocean dust-climate coupling over the past four million years.

    PubMed

    Martínez-Garcia, Alfredo; Rosell-Melé, Antoni; Jaccard, Samuel L; Geibert, Walter; Sigman, Daniel M; Haug, Gerald H

    2011-08-03

    Dust has the potential to modify global climate by influencing the radiative balance of the atmosphere and by supplying iron and other essential limiting micronutrients to the ocean. Indeed, dust supply to the Southern Ocean increases during ice ages, and 'iron fertilization' of the subantarctic zone may have contributed up to 40 parts per million by volume (p.p.m.v.) of the decrease (80-100 p.p.m.v.) in atmospheric carbon dioxide observed during late Pleistocene glacial cycles. So far, however, the magnitude of Southern Ocean dust deposition in earlier times and its role in the development and evolution of Pleistocene glacial cycles have remained unclear. Here we report a high-resolution record of dust and iron supply to the Southern Ocean over the past four million years, derived from the analysis of marine sediments from ODP Site 1090, located in the Atlantic sector of the subantarctic zone. The close correspondence of our dust and iron deposition records with Antarctic ice core reconstructions of dust flux covering the past 800,000 years (refs 8, 9) indicates that both of these archives record large-scale deposition changes that should apply to most of the Southern Ocean, validating previous interpretations of the ice core data. The extension of the record beyond the interval covered by the Antarctic ice cores reveals that, in contrast to the relatively gradual intensification of glacial cycles over the past three million years, Southern Ocean dust and iron flux rose sharply at the Mid-Pleistocene climatic transition around 1.25 million years ago. This finding complements previous observations over late Pleistocene glacial cycles, providing new evidence of a tight connection between high dust input to the Southern Ocean and the emergence of the deep glaciations that characterize the past one million years of Earth history.

  17. Latitudinal species diversity gradient of marine zooplankton for the last three million years

    USGS Publications Warehouse

    Yasuhara, Moriaki; Hunt, Gene; Dowsett, Harry J.; Robinson, Marci M.; Stoll, Danielle K.

    2012-01-01

    High tropical and low polar biodiversity is one of the most fundamental patterns characterising marine ecosystems, and the influence of temperature on such marine latitudinal diversity gradients is increasingly well documented. However, the temporal stability of quantitative relationships among diversity, latitude and temperature is largely unknown. Herein we document marine zooplankton species diversity patterns at four time slices [modern, Last Glacial Maximum (18 000 years ago), last interglacial (120 000 years ago), and Pliocene (~3.3–3.0 million years ago)] and show that, although the diversity-latitude relationship has been dynamic, diversity-temperature relationships are remarkably constant over the past three million years. These results suggest that species diversity is rapidly reorganised as species' ranges respond to temperature change on ecological time scales, and that the ecological impact of future human-induced temperature change may be partly predictable from fossil and paleoclimatological records.

  18. One million years of cultural evolution in a stable environment at Atapuerca (Burgos, Spain)

    NASA Astrophysics Data System (ADS)

    Rodríguez, J.; Burjachs, F.; Cuenca-Bescós, G.; García, N.; Van der Made, J.; Pérez González, A.; Blain, H.-A.; Expósito, I.; López-García, J. M.; García Antón, M.; Allué, E.; Cáceres, I.; Huguet, R.; Mosquera, M.; Ollé, A.; Rosell, J.; Parés, J. M.; Rodríguez, X. P.; Díez, C.; Rofes, J.; Sala, R.; Saladié, P.; Vallverdú, J.; Bennasar, M. L.; Blasco, R.; Bermúdez de Castro, J. M.; Carbonell, E.

    2011-06-01

    The present paper analyses the evidence provided by three sites (Sima del Elefante, Gran Dolina, and Galería) located in the Trinchera del Ferrocarril of the Sierra de Atapuerca. These three sites are cave infillings that contain sediments deposited from approximately 1.2 Ma to 200 kyr. Pollen, herpetofauna, and small and large mammal remains are used as proxies to obtain a general picture of the environmental changes that occurred at the Sierra de Atapuerca throughout the one million-year period represented at these sites. Similarly, cultural changes are tracked analyzing the evidence of human behavior obtained from the study of several bone and lithic assemblages from these three sites. At least three periods with different cultural features, involving technology, subsistence and behavior, are determined from the available evidence. The first two periods correspond to the Mode 1 technology and Homo antecessor: the first is dated around 1.2 to 1.0 Ma and reflects opportunistic behavior both in technology and subsistence. The second period is around 800 kyr BP. Mode 1 technology is still maintained, but subsistence strategies include systematic hunting and the use of base camps. The third period is dated between 500 ka and 200 ka and corresponds to the Mode 2 technology and the acquisition of directional hunting and other organizational strategies by Homo heidelbergensis. A transition from Mode 2 to Mode 3 seems to appear at the end of this time-range, and may reflect the early phases of a fourth cultural change. With regard to the environment, our main conclusion is that there was an absence of extremely harsh conditions at Atapuerca throughout this time period. The presence of Mediterranean taxa was constant and the dominant landscape was a savannah-like open environment, probably with small forest patches. An alternation of Mediterranean and mesic species as the dominant component of the tree storey was induced by the climatic cycles, and steppes spread across

  19. Lunar radionuclide records of average solar-cosmic-ray fluxes over the last ten million years

    NASA Technical Reports Server (NTRS)

    Reedy, R. C.

    1980-01-01

    The use of cosmogenic radionuclides in lunar materials as indicators of solar cosmic ray fluxes and thus solar activity over the past 10 million years is discussed. The nature of solar and galactic cosmic ray particles and their interactions with matter are reviewed, with particular emphasis on nuclide production by cosmic-ray-induced nuclear reactions. Evidence of galactic cosmic ray flux variations from measurements of radionuclide activities in meteorites is considered which has indicated changes of less than about 25-50% over the last few million years. Measurements of radionuclide activities in lunar materials which are used to determine solar cosmic ray fluxes are then examined together with direct proton measurements indicating variations in solar fluxes with different solar cycles. It is noted that whereas average solar proton fluxes determined for the last 1-10 million years from Al-26 and Mn-53 data show little variation and are similar to recent values, lunar C-14 and Kr-81 activities indicate average solar proton fluxes several times greater over the past 10,000 to 100,000 years.

  20. Extreme ecosystem instability suppressed tropical dinosaur dominance for 30 million years.

    PubMed

    Whiteside, Jessica H; Lindström, Sofie; Irmis, Randall B; Glasspool, Ian J; Schaller, Morgan F; Dunlavey, Maria; Nesbitt, Sterling J; Smith, Nathan D; Turner, Alan H

    2015-06-30

    A major unresolved aspect of the rise of dinosaurs is why early dinosaurs and their relatives were rare and species-poor at low paleolatitudes throughout the Late Triassic Period, a pattern persisting 30 million years after their origin and 10-15 million years after they became abundant and speciose at higher latitudes. New palynological, wildfire, organic carbon isotope, and atmospheric pCO2 data from early dinosaur-bearing strata of low paleolatitudes in western North America show that large, high-frequency, tightly correlated variations in δ(13)Corg and palynomorph ecotypes occurred within a context of elevated and increasing pCO2 and pervasive wildfires. Whereas pseudosuchian archosaur-dominated communities were able to persist in these same regions under rapidly fluctuating extreme climatic conditions until the end-Triassic, large-bodied, fast-growing tachymetabolic dinosaurian herbivores requiring greater resources were unable to adapt to unstable high CO2 environmental conditions of the Late Triassic.

  1. Extreme ecosystem instability suppressed tropical dinosaur dominance for 30 million years

    NASA Astrophysics Data System (ADS)

    Whiteside, Jessica H.; Lindström, Sofie; Irmis, Randall B.; Glasspool, Ian J.; Schaller, Morgan F.; Dunlavey, Maria; Nesbitt, Sterling J.; Smith, Nathan D.; Turner, Alan H.

    2015-06-01

    A major unresolved aspect of the rise of dinosaurs is why early dinosaurs and their relatives were rare and species-poor at low paleolatitudes throughout the Late Triassic Period, a pattern persisting 30 million years after their origin and 10-15 million years after they became abundant and speciose at higher latitudes. New palynological, wildfire, organic carbon isotope, and atmospheric pCO2 data from early dinosaur-bearing strata of low paleolatitudes in western North America show that large, high-frequency, tightly correlated variations in δ13Corg and palynomorph ecotypes occurred within a context of elevated and increasing pCO2 and pervasive wildfires. Whereas pseudosuchian archosaur-dominated communities were able to persist in these same regions under rapidly fluctuating extreme climatic conditions until the end-Triassic, large-bodied, fast-growing tachymetabolic dinosaurian herbivores requiring greater resources were unable to adapt to unstable high CO2 environmental conditions of the Late Triassic.

  2. Exceptionally preserved 450-million-year-old ordovician ostracods with brood care.

    PubMed

    Siveter, David J; Tanaka, Gengo; Farrell, Una C; Martin, Markus J; Siveter, Derek J; Briggs, Derek E G

    2014-03-31

    Ostracod crustaceans are the most abundant fossil arthropods and are characterized by a long stratigraphic range. However, their soft parts are very rarely preserved, and the presence of ostracods in rocks older than the Silurian period [1-5] was hitherto based on the occurrence of their supposed shells. Pyritized ostracods that preserve limbs and in situ embryos, including an egg within an ovary and possible hatched individuals, are here described from rocks of the Upper Ordovician Katian Stage Lorraine Group of New York State, including examples from the famous Beecher's Trilobite Bed [6, 7]. This discovery extends our knowledge of the paleobiology of ostracods by some 25 million years and provides the first unequivocal demonstration of ostracods in the Ordovician period, including the oldest known myodocope, Luprisca incuba gen. et sp. nov. It also provides conclusive evidence of a developmental brood-care strategy conserved within Ostracoda for at least 450 million years.

  3. A magnified young galaxy from about 500 million years after the Big Bang.

    PubMed

    Zheng, Wei; Postman, Marc; Zitrin, Adi; Moustakas, John; Shu, Xinwen; Jouvel, Stephanie; Høst, Ole; Molino, Alberto; Bradley, Larry; Coe, Dan; Moustakas, Leonidas A; Carrasco, Mauricio; Ford, Holland; Benítez, Narciso; Lauer, Tod R; Seitz, Stella; Bouwens, Rychard; Koekemoer, Anton; Medezinski, Elinor; Bartelmann, Matthias; Broadhurst, Tom; Donahue, Megan; Grillo, Claudio; Infante, Leopoldo; Jha, Saurabh W; Kelson, Daniel D; Lahav, Ofer; Lemze, Doron; Melchior, Peter; Meneghetti, Massimo; Merten, Julian; Nonino, Mario; Ogaz, Sara; Rosati, Piero; Umetsu, Keiichi; van der Wel, Arjen

    2012-09-20

    Re-ionization of the intergalactic medium occurred in the early Universe at redshift z ≈ 6-11, following the formation of the first generation of stars. Those young galaxies (where the bulk of stars formed) at a cosmic age of less than about 500 million years (z ≲ 10) remain largely unexplored because they are at or beyond the sensitivity limits of existing large telescopes. Understanding the properties of these galaxies is critical to identifying the source of the radiation that re-ionized the intergalactic medium. Gravitational lensing by galaxy clusters allows the detection of high-redshift galaxies fainter than what otherwise could be found in the deepest images of the sky. Here we report multiband observations of the cluster MACS J1149+2223 that have revealed (with high probability) a gravitationally magnified galaxy from the early Universe, at a redshift of z = 9.6 ± 0.2 (that is, a cosmic age of 490 ± 15 million years, or 3.6 per cent of the age of the Universe). We estimate that it formed less than 200 million years after the Big Bang (at the 95 per cent confidence level), implying a formation redshift of ≲14. Given the small sky area that our observations cover, faint galaxies seem to be abundant at such a young cosmic age, suggesting that they may be the dominant source for the early re-ionization of the intergalactic medium.

  4. A progressively wetter climate in southern East Africa over the past 1.3 million years.

    PubMed

    Johnson, T C; Werne, J P; Brown, E T; Abbott, A; Berke, M; Steinman, B A; Halbur, J; Contreras, S; Grosshuesch, S; Deino, A; Scholz, C A; Lyons, R P; Schouten, S; Damsté, J S Sinninghe

    2016-09-08

    African climate is generally considered to have evolved towards progressively drier conditions over the past few million years, with increased variability as glacial-interglacial change intensified worldwide. Palaeoclimate records derived mainly from northern Africa exhibit a 100,000-year (eccentricity) cycle overprinted on a pronounced 20,000-year (precession) beat, driven by orbital forcing of summer insolation, global ice volume and long-lived atmospheric greenhouse gases. Here we present a 1.3-million-year-long climate history from the Lake Malawi basin (10°-14° S in eastern Africa), which displays strong 100,000-year (eccentricity) cycles of temperature and rainfall following the Mid-Pleistocene Transition around 900,000 years ago. Interglacial periods were relatively warm and moist, while ice ages were cool and dry. The Malawi record shows limited evidence for precessional variability, which we attribute to the opposing effects of austral summer insolation and the temporal/spatial pattern of sea surface temperature in the Indian Ocean. The temperature history of the Malawi basin, at least for the past 500,000 years, strongly resembles past changes in atmospheric carbon dioxide and terrigenous dust flux in the tropical Pacific Ocean, but not in global ice volume. Climate in this sector of eastern Africa (unlike northern Africa) evolved from a predominantly arid environment with high-frequency variability to generally wetter conditions with more prolonged wet and dry intervals.

  5. A progressively wetter climate in southern East Africa over the past 1.3 million years

    NASA Astrophysics Data System (ADS)

    Johnson, T. C.; Werne, J. P.; Brown, E. T.; Abbott, A.; Berke, M.; Steinman, B. A.; Halbur, J.; Contreras, S.; Grosshuesch, S.; Deino, A.; Scholz, C. A.; Lyons, R. P.; Schouten, S.; Damsté, J. S. Sinninghe

    2016-09-01

    African climate is generally considered to have evolved towards progressively drier conditions over the past few million years, with increased variability as glacial-interglacial change intensified worldwide. Palaeoclimate records derived mainly from northern Africa exhibit a 100,000-year (eccentricity) cycle overprinted on a pronounced 20,000-year (precession) beat, driven by orbital forcing of summer insolation, global ice volume and long-lived atmospheric greenhouse gases. Here we present a 1.3-million-year-long climate history from the Lake Malawi basin (10°-14° S in eastern Africa), which displays strong 100,000-year (eccentricity) cycles of temperature and rainfall following the Mid-Pleistocene Transition around 900,000 years ago. Interglacial periods were relatively warm and moist, while ice ages were cool and dry. The Malawi record shows limited evidence for precessional variability, which we attribute to the opposing effects of austral summer insolation and the temporal/spatial pattern of sea surface temperature in the Indian Ocean. The temperature history of the Malawi basin, at least for the past 500,000 years, strongly resembles past changes in atmospheric carbon dioxide and terrigenous dust flux in the tropical Pacific Ocean, but not in global ice volume. Climate in this sector of eastern Africa (unlike northern Africa) evolved from a predominantly arid environment with high-frequency variability to generally wetter conditions with more prolonged wet and dry intervals.

  6. SETI@home: A Million CPU Years and Still No ETs

    SciTech Connect

    Anderson, David P.

    2001-04-11

    SETI{at}home records data at the Arecibo radio observatory, distributes it through the Internet, and analyzes it using a screensaver program, searching for signs of extraterrestrial life. In our first year of operation we analyzed 15 Terabytes of data using 400,000 years of computer time. Over 2.5 million people in 226 countries have participated. SETI{at}home is the largest computation ever performed, is the first major scientific experiment with large-scale public participation, and serves as a prototype for future distributed-computing projects.

  7. Earliest Evidence of Toxocara sp. in a 1.2-Million-Yr-Old Extinct Hyena (Pachycrocuta brevirostris) Coprolite from Northwest Pakistan.

    PubMed

    Perri, Angela R; Heinrich, Susann; Gur-Arieh, Shira; Saunders, Jeffrey J

    2017-02-01

    The study of fossil parasites can provide insight into the antiquity of host-parasite relationships and the origins and evolution of these paleoparasites. Here, a coprolite (fossilized feces) from the 1.2-million-yr-old paleontological site of Haro River Quarry in northwestern Pakistan was analyzed for paleoparasites. Micromorphological thin sectioning and Fourier-transform infrared spectrometry (FTIR) analysis confirms the coprolite belonged to a bone-eating carnivore, likely the extinct giant short-faced hyena (Pachycrocuta brevirostris). Parasitological analysis shows the coprolite to be positive for Toxocara sp. To our knowledge, this is the earliest evidence for Toxocara sp. found.

  8. From the Primitive Soup to Cyanobacteria: It May have Taken Less Than 10 Million Years

    NASA Technical Reports Server (NTRS)

    Miller, Stanley L.; Lazcano, Antonio

    1996-01-01

    Most scientific discussions on the likelihood of extraterrestrial life have been constrained by the characteristics of life on our planet and the environmental conditions under which it may have emerged. Although it has been generally assumed that this process must have been extremely slow, involving hundreds of millions or even billions of years, a number of recent discoveries have led to a considerable compression of the time believed necessary for life to appear. It is now recognized that during its early history the Earth and other bodies of the inner Solar System went through a stage of intense collisions. Some of these impacts by large asteroids or comets may have raised the terrestrial surface to sterilizing temperatures and may have evaporated the oceans and killed off life as late as 3.8 x 10(exp 9) years ago. However, there is also ample paleontological evidence derived from the 3.5 x 10(exp 9) year old Warrawoona sediments showing that only 300 million years after the period of intense impacts ended, our planet was populated by phototactic, stromatolite-forming microorganisms. Although these discoveries are now generally interpreted to imply that the origin and early evolution of life were rapid, no attempts have been made to estimate the actual time required for these processes to occur.

  9. 33 million year old Myotis (Chiroptera, Vespertilionidae) and the rapid global radiation of modern bats

    PubMed Central

    2017-01-01

    The bat genus Myotis is represented by 120+ living species and 40+ extinct species and is found on every continent except Antarctica. The time of divergence of Myotis has been contentious as has the time and place of origin of its encompassing group the Vespertilionidae, the most diverse (450+ species) and widely distributed extant bat family. Fossil Myotis species are common, especially in Europe, beginning in the Miocene but earlier records are poor. Recent study of new specimens from the Belgian early Oligocene locality of Boutersem reveals the presence of a relatively large vespertilionid. Morphological comparison and phylogenetic analysis confirms that the new, large form can be confidently assigned to the genus Myotis, making this record the earliest known for that taxon and extending the temporal range of this extant genus to over 33 million years. This suggests that previously published molecular divergence dates for crown myotines (Myotis) are too young by at least 7 million years. Additionally, examination of first fossil appearance data of 1,011 extant placental mammal genera indicates that only 13 first occurred in the middle to late Paleogene (48 to 33 million years ago) and of these, six represent bats, including Myotis. Paleogene members of both major suborders of Chiroptera (Yangochiroptera and Yinpterochiroptera) include extant genera indicating early establishment of successful and long-term adaptive strategies as bats underwent an explosive radiation near the beginning of the Early Eocene Climatic Optimum in the Old World. A second bat adaptive radiation in the New World began coincident with the Mid-Miocene Climatic Optimum. PMID:28273112

  10. Onset of Antarctic Circumpolar Current 30 million years ago as Tasmanian Gateway aligned with westerlies.

    PubMed

    Scher, Howie D; Whittaker, Joanne M; Williams, Simon E; Latimer, Jennifer C; Kordesch, Wendy E C; Delaney, Margaret L

    2015-07-30

    Earth's mightiest ocean current, the Antarctic Circumpolar Current (ACC), regulates the exchange of heat and carbon between the ocean and the atmosphere, and influences vertical ocean structure, deep-water production and the global distribution of nutrients and chemical tracers. The eastward-flowing ACC occupies a unique circumglobal pathway in the Southern Ocean that was enabled by the tectonic opening of key oceanic gateways during the break-up of Gondwana (for example, by the opening of the Tasmanian Gateway, which connects the Indian and Pacific oceans). Although the ACC is a key component of Earth's present and past climate system, the timing of the appearance of diagnostic features of the ACC (for example, low zonal gradients in water-mass tracer fields) is poorly known and represents a fundamental gap in our understanding of Earth history. Here we show, using geophysically determined positions of continent-ocean boundaries, that the deep Tasmanian Gateway opened 33.5 ± 1.5 million years ago (the errors indicate uncertainty in the boundary positions). Following this opening, sediments from Indian and Pacific cores recorded Pacific-type neodymium isotope ratios, revealing deep westward flow equivalent to the present-day Antarctic Slope Current. We observe onset of the ACC at around 30 million years ago, when Southern Ocean neodymium isotopes record a permanent shift to modern Indian-Atlantic ratios. Our reconstructions of ocean circulation show that massive reorganization and homogenization of Southern Ocean water masses coincided with migration of the northern margin of the Tasmanian Gateway into the mid-latitude westerly wind band, which we reconstruct at 64° S, near to the northern margin. Onset of the ACC about 30 million years ago coincided with major changes in global ocean circulation and probably contributed to the lower atmospheric carbon dioxide levels that appear after this time.

  11. Onset of Antarctic Circumpolar Current 30 million years ago as Tasmanian Gateway aligned with westerlies

    NASA Astrophysics Data System (ADS)

    Scher, Howie D.; Whittaker, Joanne M.; Williams, Simon E.; Latimer, Jennifer C.; Kordesch, Wendy E. C.; Delaney, Margaret L.

    2015-07-01

    Earth's mightiest ocean current, the Antarctic Circumpolar Current (ACC), regulates the exchange of heat and carbon between the ocean and the atmosphere, and influences vertical ocean structure, deep-water production and the global distribution of nutrients and chemical tracers. The eastward-flowing ACC occupies a unique circumglobal pathway in the Southern Ocean that was enabled by the tectonic opening of key oceanic gateways during the break-up of Gondwana (for example, by the opening of the Tasmanian Gateway, which connects the Indian and Pacific oceans). Although the ACC is a key component of Earth's present and past climate system, the timing of the appearance of diagnostic features of the ACC (for example, low zonal gradients in water-mass tracer fields) is poorly known and represents a fundamental gap in our understanding of Earth history. Here we show, using geophysically determined positions of continent-ocean boundaries, that the deep Tasmanian Gateway opened 33.5 +/- 1.5 million years ago (the errors indicate uncertainty in the boundary positions). Following this opening, sediments from Indian and Pacific cores recorded Pacific-type neodymium isotope ratios, revealing deep westward flow equivalent to the present-day Antarctic Slope Current. We observe onset of the ACC at around 30 million years ago, when Southern Ocean neodymium isotopes record a permanent shift to modern Indian-Atlantic ratios. Our reconstructions of ocean circulation show that massive reorganization and homogenization of Southern Ocean water masses coincided with migration of the northern margin of the Tasmanian Gateway into the mid-latitude westerly wind band, which we reconstruct at 64° S, near to the northern margin. Onset of the ACC about 30 million years ago coincided with major changes in global ocean circulation and probably contributed to the lower atmospheric carbon dioxide levels that appear after this time.

  12. 33 million year old Myotis (Chiroptera, Vespertilionidae) and the rapid global radiation of modern bats.

    PubMed

    Gunnell, Gregg F; Smith, Richard; Smith, Thierry

    2017-01-01

    The bat genus Myotis is represented by 120+ living species and 40+ extinct species and is found on every continent except Antarctica. The time of divergence of Myotis has been contentious as has the time and place of origin of its encompassing group the Vespertilionidae, the most diverse (450+ species) and widely distributed extant bat family. Fossil Myotis species are common, especially in Europe, beginning in the Miocene but earlier records are poor. Recent study of new specimens from the Belgian early Oligocene locality of Boutersem reveals the presence of a relatively large vespertilionid. Morphological comparison and phylogenetic analysis confirms that the new, large form can be confidently assigned to the genus Myotis, making this record the earliest known for that taxon and extending the temporal range of this extant genus to over 33 million years. This suggests that previously published molecular divergence dates for crown myotines (Myotis) are too young by at least 7 million years. Additionally, examination of first fossil appearance data of 1,011 extant placental mammal genera indicates that only 13 first occurred in the middle to late Paleogene (48 to 33 million years ago) and of these, six represent bats, including Myotis. Paleogene members of both major suborders of Chiroptera (Yangochiroptera and Yinpterochiroptera) include extant genera indicating early establishment of successful and long-term adaptive strategies as bats underwent an explosive radiation near the beginning of the Early Eocene Climatic Optimum in the Old World. A second bat adaptive radiation in the New World began coincident with the Mid-Miocene Climatic Optimum.

  13. Discovery of 505-million-year old chitin in the basal demosponge Vauxia gracilenta.

    PubMed

    Ehrlich, H; Rigby, J Keith; Botting, J P; Tsurkan, M V; Werner, C; Schwille, P; Petrášek, Z; Pisera, A; Simon, P; Sivkov, V N; Vyalikh, D V; Molodtsov, S L; Kurek, D; Kammer, M; Hunoldt, S; Born, R; Stawski, D; Steinhof, A; Bazhenov, V V; Geisler, T

    2013-12-13

    Sponges are probably the earliest branching animals, and their fossil record dates back to the Precambrian. Identifying their skeletal structure and composition is thus a crucial step in improving our understanding of the early evolution of metazoans. Here, we present the discovery of 505-million-year-old chitin, found in exceptionally well preserved Vauxia gracilenta sponges from the Middle Cambrian Burgess Shale. Our new findings indicate that, given the right fossilization conditions, chitin is stable for much longer than previously suspected. The preservation of chitin in these fossils opens new avenues for research into other ancient fossil groups.

  14. Discovery of 505-million-year old chitin in the basal demosponge Vauxia gracilenta

    PubMed Central

    Ehrlich, H.; Rigby, J. Keith; Botting, J. P.; Tsurkan, M. V.; Werner, C.; Schwille, P.; Petrášek, Z.; Pisera, A.; Simon, P.; Sivkov, V. N.; Vyalikh, D. V.; Molodtsov, S. L.; Kurek, D.; Kammer, M.; Hunoldt, S.; Born, R.; Stawski, D.; Steinhof, A.; Bazhenov, V. V.; Geisler, T.

    2013-01-01

    Sponges are probably the earliest branching animals, and their fossil record dates back to the Precambrian. Identifying their skeletal structure and composition is thus a crucial step in improving our understanding of the early evolution of metazoans. Here, we present the discovery of 505–million-year-old chitin, found in exceptionally well preserved Vauxia gracilenta sponges from the Middle Cambrian Burgess Shale. Our new findings indicate that, given the right fossilization conditions, chitin is stable for much longer than previously suspected. The preservation of chitin in these fossils opens new avenues for research into other ancient fossil groups. PMID:24336573

  15. Revival and Identification of Bacterial Spores in 25- to 40-Million-Year-Old Dominican Amber

    NASA Astrophysics Data System (ADS)

    Cano, Raul J.; Borucki, Monica K.

    1995-05-01

    A bacterial spore was revived, cultured, and identified from the abdominal contents of extinct bees preserved for 25 to 40 million years in buried Dominican amber. Rigorous surface decontamination of the amber and aseptic procedures were used during the recovery of the bacterium. Several lines of evidence indicated that the isolated bacterium was of ancient origin and not an extant contaminant. The characteristic enzymatic, biochemical, and 16S ribosomal DNA profiles indicated that the ancient bacterium is most closely related to extant Bacillus sphaericus.

  16. Fossilized nuclei and chromosomes reveal 180 million years of genomic stasis in royal ferns.

    PubMed

    Bomfleur, Benjamin; McLoughlin, Stephen; Vajda, Vivi

    2014-03-21

    Rapidly permineralized fossils can provide exceptional insights into the evolution of life over geological time. Here, we present an exquisitely preserved, calcified stem of a royal fern (Osmundaceae) from Early Jurassic lahar deposits of Sweden in which authigenic mineral precipitation from hydrothermal brines occurred so rapidly that it preserved cytoplasm, cytosol granules, nuclei, and even chromosomes in various stages of cell division. Morphometric parameters of interphase nuclei match those of extant Osmundaceae, indicating that the genome size of these reputed "living fossils" has remained unchanged over at least 180 million years-a paramount example of evolutionary stasis.

  17. A new ascarid species in cynodont coprolite dated of 240 million years.

    PubMed

    Silva, Priscilla A da; Borba, Victor H; Dutra, Juliana M F; Leles, Daniela; da-Rosa, Atila A S; Ferreira, Luiz F; Araujo, Adauto

    2014-03-01

    Cynodonts represent the transition from reptiles to mammals. They are classified as synapsids, or tetrapod animals with mammalian characteristics. We present here the finding of helminth eggs in a coprolite identified as of cynodont origin dated of nearly 240 million years. Microscopy revealed the presence of very well preserved intestinal parasite eggs. Up to now we identified an ascarid egg by morphological characteristics. Based on a previous description of the new genus Ascarites Poinar Jr and Boucot 2006 in coprolites of iguanodons from Belgium, we propose a new species, Ascarites rufferi n.sp. in cynodonts, a host that inhabited the Southern Region of Brazil in the Triassic period.

  18. 40-million-year lake record of early Mesozoic orbital climatic forcing

    SciTech Connect

    Olsen, P.E.

    1986-11-14

    Sediments of the early Mesozoic Newark Supergroup of eastern North America consist largely of sedimentary cycles produced by the rise and fall of very large lakes that responded to periodic climate changes controlled by variations in the earth's orbit. Fourier analysis of long sections of the Late Triassic Lockatong and Passaic formations of the Newark Basin show periods in thickness of 5.9, 10.5, 25.2, 32.0, and 96.0 meters corresponding to periodicities in time of roughly 25,000, 44,000, 100,000, 133,000 and 400,000 years, as judged by radiometric time scales and varve-calibrated sedimentation rates. The ratios of the shortest cycle with longer cycles correspond closely to the ratios of the present periods of the main orbital terms that appear to influence climate. Similar long sequences of sedimentary cycles occur through most of the rest of the Newark Supergroup spanning a period of more than 40 million years. This is strong evidence of orbital forcing of climate in the ice-free early Mesozoic and indicates that the main periods of the orbital cycles were not very different 200 million years ago from those today.

  19. A 40-million-year lake record of early mesozoic orbital climatic forcing.

    PubMed

    Olsen, P E

    1986-11-14

    Sediments of the early Mesozoic Newark Supergroup of eastern North America consist largely of sedimentary cycles produced by the rise and fall of very large lakes that responded to periodic climate changes controlled by variations in the earth's orbit. Fourier analysis of long sections of the Late Triassic Lockatong and Passaic formations of the Newark Basin show periods in thickness of 5.9, 10.5, 25.2, 32.0, and 96.0 meters corresponding to periodicities in time of roughly 25,000, 44,000, 100,0003,, 13000 and 400,000 years, as judged by radiometric time scales and varve-calibrated sedimentation rates. The ratios of the shortest cycle with longer cycles correspond closely to the ratios of the present periods of the main orbital terms that appear to influence climate. Similar long sequences of sedimentary cycles occur through most of the rest of the Newark Supergroup spanning a period of more than 40 million years. This is strong evidence of orbital forcing of climate in the ice-free early Mesozoic and indicates that the main periods of the orbital cycles were not very different 200 million years ago from those today.

  20. Anthropogenic carbon release rate unprecedented during the past 66 million years

    NASA Astrophysics Data System (ADS)

    Zeebe, Richard E.; Ridgwell, Andy; Zachos, James C.

    2016-04-01

    Carbon release rates from anthropogenic sources reached a record high of ~10 Pg C yr-1 in 2014. Geologic analogues from past transient climate changes could provide invaluable constraints on the response of the climate system to such perturbations, but only if the associated carbon release rates can be reliably reconstructed. The Palaeocene-Eocene Thermal Maximum (PETM) is known at present to have the highest carbon release rates of the past 66 million years, but robust estimates of the initial rate and onset duration are hindered by uncertainties in age models. Here we introduce a new method to extract rates of change from a sedimentary record based on the relative timing of climate and carbon cycle changes, without the need for an age model. We apply this method to stable carbon and oxygen isotope records from the New Jersey shelf using time-series analysis and carbon cycle-climate modelling. We calculate that the initial carbon release during the onset of the PETM occurred over at least 4,000 years. This constrains the maximum sustained PETM carbon release rate to less than 1.1 Pg C yr-1. We conclude that, given currently available records, the present anthropogenic carbon release rate is unprecedented during the past 66 million years. We suggest that such a `no-analogue’ state represents a fundamental challenge in constraining future climate projections. Also, future ecosystem disruptions are likely to exceed the relatively limited extinctions observed at the PETM.

  1. Twenty-million-year relationship between mammalian diversity and primary productivity.

    PubMed

    Fritz, Susanne A; Eronen, Jussi T; Schnitzler, Jan; Hof, Christian; Janis, Christine M; Mulch, Andreas; Böhning-Gaese, Katrin; Graham, Catherine H

    2016-09-27

    At global and regional scales, primary productivity strongly correlates with richness patterns of extant animals across space, suggesting that resource availability and climatic conditions drive patterns of diversity. However, the existence and consistency of such diversity-productivity relationships through geological history is unclear. Here we provide a comprehensive quantitative test of the diversity-productivity relationship for terrestrial large mammals through time across broad temporal and spatial scales. We combine >14,000 occurrences for 690 fossil genera through the Neogene (23-1.8 Mya) with regional estimates of primary productivity from fossil plant communities in North America and Europe. We show a significant positive diversity-productivity relationship through the 20-million-year record, providing evidence on unprecedented spatial and temporal scales that this relationship is a general pattern in the ecology and paleo-ecology of our planet. Further, we discover that genus richness today does not match the fossil relationship, suggesting that a combination of human impacts and Pleistocene climate variability has modified the 20-million-year ecological relationship by strongly reducing primary productivity and driving many mammalian species into decline or to extinction.

  2. Physical mapping of the elephant X chromosome: conservation of gene order over 105 million years.

    PubMed

    Delgado, Claudia Leticia Rodríguez; Waters, Paul D; Gilbert, Clément; Robinson, Terence J; Graves, Jennifer A Marshall

    2009-01-01

    All therian mammals (eutherians and marsupials) have an XX female/XY male sex chromosome system or some variant of it. The X and Y evolved from a homologous pair of autosomes over the 166 million years since therian mammals diverged from monotremes. Comparing the sex chromosomes of eutherians and marsupials defined an ancient X conserved region that is shared between species of these mammalian clades. However, the eutherian X (and the Y) was augmented by a recent addition (XAR) that is autosomal in marsupials. XAR is part of the X in primates, rodents, and artiodactyls (which belong to the eutherian clade Boreoeutheria), but it is uncertain whether XAR is part of the X chromosome in more distantly related eutherian mammals. Here we report on the gene content and order on the X of the elephant (Loxodonta africana)-a representative of Afrotheria, a basal endemic clade of African mammals-and compare these findings to those of other documented eutherian species. A total of 17 genes were mapped to the elephant X chromosome. Our results support the hypothesis that the eutherian X and Y chromosomes were augmented by the addition of autosomal material prior to eutherian radiation. Not only does the elephant X bear the same suite of genes as other eutherian X chromosomes, but gene order appears to have been maintained across 105 million years of evolution, perhaps reflecting strong constraints posed by the eutherian X inactivation system.

  3. Isolation of a 250 million-year-old halotolerant bacterium from a primary salt crystal

    NASA Astrophysics Data System (ADS)

    Vreeland, Russell H.; Rosenzweig, William D.; Powers, Dennis W.

    2000-10-01

    Bacteria have been found associated with a variety of ancient samples, however few studies are generally accepted due to questions about sample quality and contamination. When Cano and Borucki isolated a strain of Bacillus sphaericus from an extinct bee trapped in 25-30 million-year-old amber, careful sample selection and stringent sterilization techniques were the keys to acceptance. Here we report the isolation and growth of a previously unrecognized spore-forming bacterium (Bacillus species, designated 2-9-3) from a brine inclusion within a 250million-year-old salt crystal from the Permian Salado Formation. Complete gene sequences of the 16S ribosomal DNA show that the organism is part of the lineage of Bacillus marismortui and Virgibacillus pantothenticus. Delicate crystal structures and sedimentary features indicate the salt has not recrystallized since formation. Samples were rejected if brine inclusions showed physical signs of possible contamination. Surfaces of salt crystal samples were sterilized with strong alkali and acid before extracting brines from inclusions. Sterilization procedures reduce the probability of contamination to less than 1 in 10 9.

  4. Earliest Porotic Hyperostosis on a 1.5-Million-Year-Old Hominin, Olduvai Gorge, Tanzania

    PubMed Central

    Domínguez-Rodrigo, Manuel; Pickering, Travis Rayne; Diez-Martín, Fernando; Mabulla, Audax; Musiba, Charles; Trancho, Gonzalo; Baquedano, Enrique; Bunn, Henry T.; Barboni, Doris; Santonja, Manuel; Uribelarrea, David; Ashley, Gail M.; Martínez-Ávila, María del Sol; Barba, Rebeca; Gidna, Agness; Yravedra, José; Arriaza, Carmen

    2012-01-01

    Meat-eating was an important factor affecting early hominin brain expansion, social organization and geographic movement. Stone tool butchery marks on ungulate fossils in several African archaeological assemblages demonstrate a significant level of carnivory by Pleistocene hominins, but the discovery at Olduvai Gorge of a child's pathological cranial fragments indicates that some hominins probably experienced scarcity of animal foods during various stages of their life histories. The child's parietal fragments, excavated from 1.5-million-year-old sediments, show porotic hyperostosis, a pathology associated with anemia. Nutritional deficiencies, including anemia, are most common at weaning, when children lose passive immunity received through their mothers' milk. Our results suggest, alternatively, that (1) the developmentally disruptive potential of weaning reached far beyond sedentary Holocene food-producing societies and into the early Pleistocene, or that (2) a hominin mother's meat-deficient diet negatively altered the nutritional content of her breast milk to the extent that her nursing child ultimately died from malnourishment. Either way, this discovery highlights that by at least 1.5 million years ago early human physiology was already adapted to a diet that included the regular consumption of meat. PMID:23056303

  5. Twenty-million-year relationship between mammalian diversity and primary productivity

    PubMed Central

    Fritz, Susanne A.; Eronen, Jussi T.; Schnitzler, Jan; Hof, Christian; Janis, Christine M.; Mulch, Andreas; Böhning-Gaese, Katrin; Graham, Catherine H.

    2016-01-01

    At global and regional scales, primary productivity strongly correlates with richness patterns of extant animals across space, suggesting that resource availability and climatic conditions drive patterns of diversity. However, the existence and consistency of such diversity–productivity relationships through geological history is unclear. Here we provide a comprehensive quantitative test of the diversity–productivity relationship for terrestrial large mammals through time across broad temporal and spatial scales. We combine >14,000 occurrences for 690 fossil genera through the Neogene (23–1.8 Mya) with regional estimates of primary productivity from fossil plant communities in North America and Europe. We show a significant positive diversity–productivity relationship through the 20-million-year record, providing evidence on unprecedented spatial and temporal scales that this relationship is a general pattern in the ecology and paleo-ecology of our planet. Further, we discover that genus richness today does not match the fossil relationship, suggesting that a combination of human impacts and Pleistocene climate variability has modified the 20-million-year ecological relationship by strongly reducing primary productivity and driving many mammalian species into decline or to extinction. PMID:27621451

  6. Lunar surface processes and cosmic ray histories over the past several million years

    NASA Technical Reports Server (NTRS)

    Fruchter, J. S.; Rancitelli, L. A.; Evans, J. C.; Perkins, R. W.

    1978-01-01

    Measurements of the Al-26 and Mn-53 in interior portions of lunar rocks have shown that lunar surface processes which move a significant fraction of kilogram size rocks on the lunar surface occur on time scales of a few million years. These measurements, together with noble gas age dating have made it possible to define the history for nine rock samples selected from whole rock counting data because of anomalously low Al-26 relative to Na-22. Six of the rocks from the Apollo 15 and 16 missions showed evidence of movement during the past five million years. Of these six, only two are of an age consistent with their origin from the South Ray Crater Event. In addition, our measurements of Na-22 and Al-26 in Apollo 17 double drive tube 74001-74002 suggest that one to two cm of soil is missing from the top of this core tube. Even with this loss, at least two cm of gardening is indicated in the top portion of 74002.

  7. Twenty-million-year relationship between mammalian diversity and primary productivity

    NASA Astrophysics Data System (ADS)

    Fritz, Susanne A.; Eronen, Jussi T.; Schnitzler, Jan; Hof, Christian; Janis, Christine M.; Mulch, Andreas; Böhning-Gaese, Katrin; Graham, Catherine H.

    2016-09-01

    At global and regional scales, primary productivity strongly correlates with richness patterns of extant animals across space, suggesting that resource availability and climatic conditions drive patterns of diversity. However, the existence and consistency of such diversity-productivity relationships through geological history is unclear. Here we provide a comprehensive quantitative test of the diversity-productivity relationship for terrestrial large mammals through time across broad temporal and spatial scales. We combine >14,000 occurrences for 690 fossil genera through the Neogene (23-1.8 Mya) with regional estimates of primary productivity from fossil plant communities in North America and Europe. We show a significant positive diversity-productivity relationship through the 20-million-year record, providing evidence on unprecedented spatial and temporal scales that this relationship is a general pattern in the ecology and paleo-ecology of our planet. Further, we discover that genus richness today does not match the fossil relationship, suggesting that a combination of human impacts and Pleistocene climate variability has modified the 20-million-year ecological relationship by strongly reducing primary productivity and driving many mammalian species into decline or to extinction.

  8. The complete genome of a viable archaeum isolated from 123-million-year-old rock salt.

    PubMed

    Jaakkola, Salla T; Pfeiffer, Friedhelm; Ravantti, Janne J; Guo, Qinggong; Liu, Ying; Chen, Xiangdong; Ma, Hongling; Yang, Chunhe; Oksanen, Hanna M; Bamford, Dennis H

    2016-02-01

    Live microbes have been isolated from rock salt up to Permian age. Only obligatory cellular functions can be performed in halite-buried cells. Consequently, their genomic sequences are likely to remain virtually unchanged. However, the available sequence information from these organisms is scarce and consists of mainly ribosomal 16S sequences. Here, live archaea were isolated from early Cretaceous (∼ 123 million years old) halite from the depth of 2000 m in Qianjiang Depression, Hubei Province, China. The sample was radiologically dated and subjected to rigorous surface sterilization before microbe isolation. The isolates represented a single novel species of Halobacterium, for which we suggest the name Halobacterium hubeiense, type strain Hbt. hubeiense JI20-1. The species was closely related to a Permian (225-280 million years old) isolate, Halobacterium noricense, originating from Alpine rock salt. This study is the first one to publish the complete genome of an organism originating from surface-sterilized ancient halite. In the future, genomic data from halite-buried microbes can become a key factor in understanding the mechanisms by which these organisms are able to survive in harsh conditions deep underground or possibly on other celestial bodies.

  9. Yucca mountain - From 10,000 to 1-Million year compliance period

    SciTech Connect

    Vawter, R.G.

    2007-07-01

    Two plus years ago a U.S. Federal Court of Appeals (the Court) ruled that EPA had not followed the recommendation of the National Academy of Science (NAS) with regard to the 10,000 year period of regulatory compliance. In response to that ruling EPA went back to the drawing board in 2005 and issued a draft rule that it believed complied with the Court's ruling and the intent of the NAS recommendation. The result is a recommendation to cause there to be compliance out to 1- million years. It is the author's belief that thinking in terms of 1-million years is absurd, not based upon scientific information, and just results in yet another delay for an environmental program sorely needed by this country, especially in light of the nuclear power renaissance emerging at this time around the world. So, the Yucca Mountain Project is at yet another critical juncture. It is facing a decision to either clear the political and regulatory issues and move ahead; continue to be stalled costing the nation billions of wasted dollars; or be moth balled until a solution is reached. The Department of Energy has announced that waste acceptance will be delayed until at least 2017 and it is hard to comprehend why the project should continue to be funded at current levels. It is the author's opinion that only Congress can clear these obstacles so the project can move forward in a safe and efficient manner. This paper will present the history of the ever increasing compliance period for Yucca Mountain; the need to reevaluate the regulatory strategy; the events that have occurred in the history of man and geologically in a million year time span; the absence of a mechanism for enforcing such regulations; the approach other countries are taking on this issue; the absurdity of trying to protecting people thousand of generations in the future from radiation doses that our generation is already exposed to from mostly natural causes, and lastly proposes a rational compliance period and regulatory

  10. Climatic influences on deep-sea ostracode (Crustacea) diversity for the last three million years.

    PubMed

    Yasuhara, Moriaki; Cronin, Thomas M

    2008-11-01

    Ostracodes are small, bivalved crustaceans with the finest-scale fossil resolution of any metazoan, rivaled only by the fossil record of the protistan Foraminifera. This article presents a synthesis of the patterns and possible causes of alpha species diversity variation in benthic deep-sea ostracodes at drilling sites in the North Atlantic and Arctic Oceans. Taken together, these sites represent a period of great climatic variability covering the past three million years. Sediment cores taken from the Mid-Atlantic Ridge show a positive correlation between warm temperatures and high species diversity. These Mid-Atlantic Ridge cores, at the same latitude as northern Spain, show the same positive correlation during the last two glacial-interglacial cycles (200-0 ka [thousands of years ago]) as they do during the pre-glacial Pliocene 2.85-2.4 Ma (millions of years ago). This positive correlation is also found in Pliocene cores from the Rockall Plateau, at the same latitude as Ireland. During the last 200 thousand years, however, this correlation is reversed in cores taken from both the Rockall and Iceland Plateaus. The discovery of high diversity during colder periods in recent high-latitude Rockall and Iceland cores seems to be explained by spikes in diversity caused by ice-rafting events, which would not affect the lower-latitude Mid-Atlantic Ridge. The Heinrich ice-rafting events reduce North Atlantic surface temperatures and salinity every approximately 6-12 ka, dramatically decreasing surface productivity. This increase in diversity during Heinrich events may be explained either by a negative correlation between surface productivity and benthic diversity or by increase in diversity caused by moderate disturbance when ice rafted debris fall to the bottom of the ocean.

  11. Gene flow persists millions of years after speciation in Heliconius butterflies

    PubMed Central

    2008-01-01

    Background Hybridization, or the interbreeding of two species, is now recognized as an important process in the evolution of many organisms. However, the extent to which hybridization results in the transfer of genetic material across the species boundary (introgression) remains unknown in many systems, as does the length of time after initial divergence that the species boundary remains porous to such gene flow. Results Here I use genome-wide genotypic and DNA sequence data to show that there is introgression and admixture between the melpomene/cydno and silvaniform clades of the butterfly genus Heliconius, groups that separated from one another as many as 30 million generations ago. Estimates of historical migration based on 523 DNA sequences from 14 genes suggest unidirectional gene flow from the melpomene/cydno clade into the silvaniform clade. Furthermore, genetic clustering based on 520 amplified fragment length polymorphisms (AFLPs) identified multiple individuals of mixed ancestry showing that introgression is on-going. Conclusion These results demonstrate that genomes can remain porous to gene flow very long after initial divergence. This, in turn, greatly expands the evolutionary potential afforded by introgression. Phenotypic and species diversity in a wide variety of organisms, including Heliconius, have likely arisen from introgressive hybridization. Evidence for continuous gene flow over millions of years points to introgression as a potentially important source of genetic variation to fuel the evolution of novel forms. PMID:18371203

  12. A persistent and dynamic East Greenland Ice Sheet over the past 7.5 million years.

    PubMed

    Bierman, Paul R; Shakun, Jeremy D; Corbett, Lee B; Zimmerman, Susan R; Rood, Dylan H

    2016-12-07

    Climate models show that ice-sheet melt will dominate sea-level rise over the coming centuries, but our understanding of ice-sheet variations before the last interglacial 125,000 years ago remains fragmentary. This is because terrestrial deposits of ancient glacial and interglacial periods are overrun and eroded by more recent glacial advances, and are therefore usually rare, isolated and poorly dated. In contrast, material shed almost continuously from continents is preserved as marine sediment that can be analysed to infer the time-varying state of major ice sheets. Here we show that the East Greenland Ice Sheet existed over the past 7.5 million years, as indicated by beryllium and aluminium isotopes ((10)Be and (26)Al) in quartz sand removed by deep, ongoing glacial erosion on land and deposited offshore in the marine sedimentary record. During the early Pleistocene epoch, ice cover in East Greenland was dynamic; in contrast, East Greenland was mostly ice-covered during the mid-to-late Pleistocene. The isotope record we present is consistent with distinct signatures of changes in ice sheet behaviour coincident with major climate transitions. Although our data are continuous, they are from low-deposition-rate sites and sourced only from East Greenland. Consequently, the signal of extensive deglaciation during short, intense interglacials could be missed or blurred, and we cannot distinguish between a remnant ice sheet in the East Greenland highlands and a diminished continent-wide ice sheet. A clearer constraint on the behaviour of the ice sheet during past and, ultimately, future interglacial warmth could be produced by (10)Be and (26)Al records from a coring site with a higher deposition rate. Nonetheless, our analysis challenges the possibility of complete and extended deglaciation over the past several million years.

  13. A persistent and dynamic East Greenland Ice Sheet over the past 7.5 million years

    NASA Astrophysics Data System (ADS)

    Bierman, Paul R.; Shakun, Jeremy D.; Corbett, Lee B.; Zimmerman, Susan R.; Rood, Dylan H.

    2016-12-01

    Climate models show that ice-sheet melt will dominate sea-level rise over the coming centuries, but our understanding of ice-sheet variations before the last interglacial 125,000 years ago remains fragmentary. This is because terrestrial deposits of ancient glacial and interglacial periods are overrun and eroded by more recent glacial advances, and are therefore usually rare, isolated and poorly dated. In contrast, material shed almost continuously from continents is preserved as marine sediment that can be analysed to infer the time-varying state of major ice sheets. Here we show that the East Greenland Ice Sheet existed over the past 7.5 million years, as indicated by beryllium and aluminium isotopes (10Be and 26Al) in quartz sand removed by deep, ongoing glacial erosion on land and deposited offshore in the marine sedimentary record. During the early Pleistocene epoch, ice cover in East Greenland was dynamic; in contrast, East Greenland was mostly ice-covered during the mid-to-late Pleistocene. The isotope record we present is consistent with distinct signatures of changes in ice sheet behaviour coincident with major climate transitions. Although our data are continuous, they are from low-deposition-rate sites and sourced only from East Greenland. Consequently, the signal of extensive deglaciation during short, intense interglacials could be missed or blurred, and we cannot distinguish between a remnant ice sheet in the East Greenland highlands and a diminished continent-wide ice sheet. A clearer constraint on the behaviour of the ice sheet during past and, ultimately, future interglacial warmth could be produced by 10Be and 26Al records from a coring site with a higher deposition rate. Nonetheless, our analysis challenges the possibility of complete and extended deglaciation over the past several million years.

  14. Model reconstruction of CO_{2} over the past five million years

    NASA Astrophysics Data System (ADS)

    Stap, Lennert; De Boer, Bas; Ziegler, Martin; Bintanja, Richard; Lourens, Lucas; Van De Wal, Roderik

    2015-04-01

    Over the past five million years, climates ranged from warmer than today during the Pliocene Warm Period to considerably colder during glacials. Proxy data on sea level and CO2 in the pre-ice core period, however, are scarce and intermittent. This hampers understanding of the long-term relations between these variables and the climate. This study focuses on reconciling knowledge on benthic δ18O, CO2, sea level and climate, using a fully coupled climate-ice sheet model, inversely forced by a stacked benthic δ18O record. We obtain the first continuous five-million-year record of CO2, mutually consistent with sea level and temperature. During the Pliocene, we simulate significantly higher CO2 levels than during the Pleistocene. A compilation of existing δ11B-based proxy CO2 data and a new δ11B data record provide support for this result. In our model, limited variability of ice volume reduces ice sheet-climate feedbacks during this time. As a result, CO2 changes need to be larger to obtain similar temperature changes as during the Pleistocene. This indicates a changing relation between CO2 and temperature over time. However, while increasing the ablation rate on the East Antarctic ice sheet results in larger sea level fluctuations, it only modestly affects the simulated CO2. This is explained by the surface albedo change being limited if the Antarctic ice sheet retreats during the Pliocene, because the exposed land remains snow covered throughout most of the year.

  15. First solar system solids to proto-planets: A Rapid growth in a few million years

    NASA Astrophysics Data System (ADS)

    Goswami, Jitendranath

    2016-07-01

    First solar system solids to proto-planets: A Rapid growth in a few million years J. N. Goswami Physical Research Laboratory Ahmedabad-380009, India Collapse of a dense molecular cloud led to the formation of the proto-Sun surrounded by a high temperature gaseous nebula. The nebula settled down to the mid-plane and formation of the first solar system solids, refractory oxides and silicates, such as Corundum, Perovskite, Melilite took place, that was followed by formation of more common silicate minerals. Laboratory studies of primitive meteorites support this scenario and also provide evidence for correlated presence of several now-extinct short-lived nuclides (e.g. 41Ca, 26Al, 60Fe) at the time of formation of the first solar system solids. Presence of 60Fe in early solar system solids suggests injection of freshly synthesized nuclides from a stellar source (a supernova) into the proto-solar cloud that also triggered its collapse and led to formation of our solar system. Presence of 41Ca (half-life: 0.1Ma) in early solar system solids suggest a time scale of less than a million years for the collapse of the proto-solar cloud and formation of proto-Sun and the first solar system solids. The gradual evolution of larger solar system objects, up to planetesimals (represented by the asteroids), took place at a rapid pace within a time scale of a few million years. Some of the asteroids retain their pristine nature (e.g. parent bodies of carbonaceous chondrite), while others, underwent melting and differentiation due to internal heating. Harold Urey proposed radioactive 26Al as a possible heat source that was confirmed by experiment only in 1999. Irons and stony iron meteorites are fragments from core regions of differentiated asteroids. Extensive computer simulation studies suggest that an explosive stellar event (e.g. supernova) can indeed trigger the collapse of the proto-solar cloud and also inject freshly synthesized short-lived nuclides into it within a relatively

  16. Lunar radionuclide records of average solar-cosmic-ray fluxes over the last ten million years

    SciTech Connect

    Reedy, R.C.

    1980-03-21

    Because changes in solar activity can modify the fluxes of cosmic-ray particles in the solar system, the nature of the galactic and solar cosmic rays and their interactions with matter are described and used to study the ancient sun. The use of cosmogenic nuclides in meteorites and lunar samples as detectors of past cosmic-ray variations are discussed. Meteorite records of the history of the galactic cosmic rays are reviewed. The fluxes of solar protons over various time periods as determined from lunar radionuclide data are presented and examined. The intensities of solar protons emitted during 1954 to 1964 (11-year solar cycle number 19) were much larger than those for 1965 to 1975 (solar cycle 20). Average solar-proton fluxes determined for the last one to ten million years from lunar /sup 26/Al and /sup 53/Mn data show little variation and are similar to the fluxes for recent solar cycles. Lunar activities of /sup 14/C (and preliminary results for /sup 81/Kr) indicate that the average fluxes of solar protons over the last 10/sup 4/ (and 10/sup 5/) years are several times larger than those for the last 10/sup 6/ to 10/sup 7/ years; however, cross-section measurements and other work are needed to confirm these flux variations.

  17. Conservation of miRNA-mediated silencing mechanisms across 600 million years of animal evolution

    PubMed Central

    Mauri, Marta; Kirchner, Marieluise; Aharoni, Reuven; Ciolli Mattioli, Camilla; van den Bruck, David; Gutkovitch, Nadya; Modepalli, Vengamanaidu; Selbach, Matthias; Moran, Yehu; Chekulaeva, Marina

    2017-01-01

    Our current knowledge about the mechanisms of miRNA silencing is restricted to few lineages such as vertebrates, arthropods, nematodes and land plants. miRNA-mediated silencing in bilaterian animals is dependent on the proteins of the GW182 family. Here, we dissect the function of GW182 protein in the cnidarian Nematostella, separated by 600 million years from other Metazoa. Using cultured human cells, we show that Nematostella GW182 recruits the CCR4-NOT deadenylation complexes via its tryptophan-containing motifs, thereby inhibiting translation and promoting mRNA decay. Further, similarly to bilaterians, GW182 in Nematostella is recruited to the miRNA repression complex via interaction with Argonaute proteins, and functions downstream to repress mRNA. Thus, our work suggests that this mechanism of miRNA-mediated silencing was already active in the last common ancestor of Cnidaria and Bilateria. PMID:27604873

  18. 100-million-year dynasty of giant planktivorous bony fishes in the Mesozoic seas.

    PubMed

    Friedman, Matt; Shimada, Kenshu; Martin, Larry D; Everhart, Michael J; Liston, Jeff; Maltese, Anthony; Triebold, Michael

    2010-02-19

    Large-bodied suspension feeders (planktivores), which include the most massive animals to have ever lived, are conspicuously absent from Mesozoic marine environments. The only clear representatives of this trophic guild in the Mesozoic have been an enigmatic and apparently short-lived Jurassic group of extinct pachycormid fishes. Here, we report several new examples of these giant bony fishes from Asia, Europe, and North America. These fossils provide the first detailed anatomical information on this poorly understood clade and extend its range from the lower Middle Jurassic to the end of the Cretaceous, showing that this group persisted for more than 100 million years. Modern large-bodied, planktivorous vertebrates diversified after the extinction of pachycormids at the Cretaceous-Paleogene boundary, which is consistent with an opportunistic refilling of vacated ecospace.

  19. Protein molecular data from ancient (>1 million years old) fossil material: pitfalls, possibilities and grand challenges.

    PubMed

    Schweitzer, Mary Higby; Schroeter, Elena R; Goshe, Michael B

    2014-07-15

    Advances in resolution and sensitivity of analytical techniques have provided novel applications, including the analyses of fossil material. However, the recovery of original proteinaceous components from very old fossil samples (defined as >1 million years (1 Ma) from previously named limits in the literature) is far from trivial. Here, we discuss the challenges to recovery of proteinaceous components from fossils, and the need for new sample preparation techniques, analytical methods, and bioinformatics to optimize and fully utilize the great potential of information locked in the fossil record. We present evidence for survival of original components across geological time, and discuss the potential benefits of recovery, analyses, and interpretation of fossil materials older than 1 Ma, both within and outside of the fields of evolutionary biology.

  20. Brood care in a 100-million-year-old scale insect.

    PubMed

    Wang, Bo; Xia, Fangyuan; Wappler, Torsten; Simon, Ewa; Zhang, Haichun; Jarzembowski, Edmund A; Szwedo, Jacek

    2015-03-31

    Behavior of extinct organisms can be inferred only indirectly, but occasionally rare fossils document particular behaviors directly. Brood care, a remarkable behavior promoting the survival of the next generation, has evolved independently numerous times among animals including insects. However, fossil evidence of such a complex behavior is exceptionally scarce. Here, we report an ensign scale insect (Hemiptera: Ortheziidae), Wathondara kotejai gen. et sp. nov., from mid-Cretaceous Burmese amber, which preserves eggs within a wax ovisac, and several freshly hatched nymphs. The new fossil is the only Mesozoic record of an adult female scale insect. More importantly, our finding represents the earliest unequivocal direct evidence of brood care in the insect fossil record and demonstrates a remarkably conserved egg-brooding reproductive strategy within scale insects in stasis for nearly 100 million years.

  1. The Anguilla spp. migration problem: 40 million years of evolution and two millennia of speculation.

    PubMed

    Righton, D; Aarestrup, K; Jellyman, D; Sébert, P; van den Thillart, G; Tsukamoto, K

    2012-07-01

    Anguillid eels Anguilla spp. evolved between 20 and 40 million years ago and possess a number of remarkable migratory traits that have fascinated scientists for millennia. Despite centuries of effort, the spawning areas and migrations are known only for a few species. Even for these species, information on migratory behaviour is remarkably sketchy. The latest knowledge on the requirements for successful migration and field data on the migrations of adults and larvae are presented, how experiments on swimming efficiency have progressed the understanding of migration are highlighted and the challenges of swimming at depth considered. The decline of Anguilla spp. across the world is an ongoing concern for fisheries and environmental managers. New developments in the knowledge of eel migration will, in addition to solving a centuries old mystery, probably help to identify how this decline might be halted or even reversed.

  2. Geological and geochemical record of 3400-million-year-old terrestrial meteorite impacts

    NASA Technical Reports Server (NTRS)

    Lowe, Donald R.; Byerly, Gary R.; Asaro, Frank; Kyte, Frank T.

    1989-01-01

    Beds of sand-sized spherules in the 3400-million-year-old Fig Tree Group, Barberton Greenstone belt, South Africa, formed by the fall of quenched liquid silicate droplets into a range of shallow- to deep-water depositional environments. The regional extent of the layers, their compositional complexity, and lack of included volcanic debris suggest that they are not products of volcanic activity. The layers are greatly enriched in iridium and other platinum group elements in roughly chondritic proportions. Geochemical modeling based on immobile element abundances suggests that the original average spherule composition can be approximated by a mixture of fractionated tholeiitic basalt, komatiite, and CI carbonaceous chondrite. The spherules are thought to be the products of large meteorite impacts on the Archean earth.

  3. 60 million years of co-divergence in the fig–wasp symbiosis

    PubMed Central

    Rønsted, Nina; Weiblen, George D; Cook, James M; Salamin, Nicolas; Machado, Carlos A; Savolainen, Vincent

    2005-01-01

    Figs (Ficus; ca 750 species) and fig wasps (Agaoninae) are obligate mutualists: all figs are pollinated by agaonines that feed exclusively on figs. This extraordinary symbiosis is the most extreme example of specialization in a plant–pollinator interaction and has fuelled much speculation about co-divergence. The hypothesis that pollinator specialization led to the parallel diversification of fig and pollinator lineages (co-divergence) has so far not been tested due to the lack of robust and comprehensive phylogenetic hypotheses for both partners. We produced and combined the most comprehensive molecular phylogenetic trees to date with fossil data to generate independent age estimates for fig and pollinator lineages, using both non-parametric rate smoothing and penalized likelihood dating methods. Molecular dating of ten pairs of interacting lineages provides an unparalleled example of plant–insect co-divergence over a geological time frame spanning at least 60 million years. PMID:16321781

  4. The Surface Age of Sputnik Planum, Pluto, Must Be Less than 10 Million Years

    PubMed Central

    Trilling, David E.

    2016-01-01

    Data from the New Horizons mission to Pluto show no craters on Sputnik Planum down to the detection limit (2 km for low resolution data, 625 m for high resolution data). The number of small Kuiper Belt Objects that should be impacting Pluto is known to some degree from various astronomical surveys. We combine these geological and telescopic observations to make an order of magnitude estimate that the surface age of Sputnik Planum must be less than 10 million years. This maximum surface age is surprisingly young and implies that this area of Pluto must be undergoing active resurfacing, presumably through some cryo-geophysical process. We discuss three possible resurfacing mechanisms and the implications of each one for Pluto’s physical properties. PMID:26790001

  5. The Surface Age of Sputnik Planum, Pluto, Must Be Less than 10 Million Years.

    PubMed

    Trilling, David E

    2016-01-01

    Data from the New Horizons mission to Pluto show no craters on Sputnik Planum down to the detection limit (2 km for low resolution data, 625 m for high resolution data). The number of small Kuiper Belt Objects that should be impacting Pluto is known to some degree from various astronomical surveys. We combine these geological and telescopic observations to make an order of magnitude estimate that the surface age of Sputnik Planum must be less than 10 million years. This maximum surface age is surprisingly young and implies that this area of Pluto must be undergoing active resurfacing, presumably through some cryo-geophysical process. We discuss three possible resurfacing mechanisms and the implications of each one for Pluto's physical properties.

  6. Natural hybridization between genera that diverged from each other approximately 60 million years ago.

    PubMed

    Rothfels, Carl J; Johnson, Anne K; Hovenkamp, Peter H; Swofford, David L; Roskam, Harry C; Fraser-Jenkins, Christopher R; Windham, Michael D; Pryer, Kathleen M

    2015-03-01

    A fern from the French Pyrenees-×Cystocarpium roskamianum-is a recently formed intergeneric hybrid between parental lineages that diverged from each other approximately 60 million years ago (mya; 95% highest posterior density: 40.2-76.2 mya). This is an extraordinarily deep hybridization event, roughly akin to an elephant hybridizing with a manatee or a human with a lemur. In the context of other reported deep hybrids, this finding suggests that populations of ferns, and other plants with abiotically mediated fertilization, may evolve reproductive incompatibilities more slowly, perhaps because they lack many of the premating isolation mechanisms that characterize most other groups of organisms. This conclusion implies that major features of Earth's biodiversity-such as the relatively small number of species of ferns compared to those of angiosperms-may be, in part, an indirect by-product of this slower "speciation clock" rather than a direct consequence of adaptive innovations by the more diverse lineages.

  7. 2.5-million-year-old stone tools from Gona, Ethiopia.

    PubMed

    Semaw, S; Renne, P; Harris, J W; Feibel, C S; Bernor, R L; Fesseha, N; Mowbray, K

    1997-01-23

    The Oldowan Stone tool industry was named for 1.8-million-year-old (Myr) artefacts found near the bottom of Olduvai Gorge, Tanzania. Subsequent archaeological research in the Omo (Ethiopia) and Turkana (Kenya) also yielded stone tools dated to 2.3 Myr. Palaeoanthropological investigations in the Hadar region of the Awash Valley of Ethiopia, revealed Oldowan assemblages in the adjacent Gona River drainage. We conducted field work in the Gona study area of Ethiopia between 1992 and 1994 which resulted in additional archaeological discoveries as well as radioisotopic age control and a magnetic polarity stratigraphy of the Gona sequence. These occurrences are now securely dated between 2.6-2.5 Myr. The stone tools are thus the oldest known artefacts from anywhere in the world. The artefacts show surprisingly sophisticated control of stone fracture mechanics, equivalent to much younger Oldowan assemblages of Early Pleistocene age. This indicates an unexpectedly long period of technological stasis in the Oldowan.

  8. River-margin habitat of Ardipithecus ramidus at Aramis, Ethiopia 4.4 million years ago.

    PubMed

    Gani, M Royhan; Gani, Nahid D

    2011-12-20

    The nature and type of landscape that hominins (early humans) frequented has been of considerable interest. The recent works on Ardipithecus ramidus, a 4.4 million years old hominin found at Middle Awash, Ethiopia, provided critical information about the early part of human evolution. However, habitat characterization of this basal hominin has been highly contested. Here we present new sedimentological and stable isotopic (carbon and oxygen) data from Aramis, where the in situ, partial skeleton of Ar. ramidus (nicknamed 'Ardi') was excavated. These data are interpreted to indicate the presence of major rivers and associated mixed vegetations (grasses and trees) in adjacent floodplains. Our finding suggests that, in contrast to a woodland habitat far from a river, Ar. ramidus lived in a river-margin forest in an otherwise savanna (wooded grassland) landscape at Aramis, Ethiopia. Correct interpretation of habitat of Ar. ramidus is crucial for proper assessment of causes and mechanisms of early hominin evolution, including the development of bipedalism.

  9. River-margin habitat of Ardipithecus ramidus at Aramis, Ethiopia 4.4 million years ago

    NASA Astrophysics Data System (ADS)

    Gani, M. Royhan; Gani, Nahid D.

    2011-12-01

    The nature and type of landscape that hominins (early humans) frequented has been of considerable interest. The recent works on Ardipithecus ramidus, a 4.4 million years old hominin found at Middle Awash, Ethiopia, provided critical information about the early part of human evolution. However, habitat characterization of this basal hominin has been highly contested. Here we present new sedimentological and stable isotopic (carbon and oxygen) data from Aramis, where the in situ, partial skeleton of Ar. ramidus (nicknamed 'Ardi') was excavated. These data are interpreted to indicate the presence of major rivers and associated mixed vegetations (grasses and trees) in adjacent floodplains. Our finding suggests that, in contrast to a woodland habitat far from a river, Ar. ramidus lived in a river-margin forest in an otherwise savanna (wooded grassland) landscape at Aramis, Ethiopia. Correct interpretation of habitat of Ar. ramidus is crucial for proper assessment of causes and mechanisms of early hominin evolution, including the development of bipedalism.

  10. Conservation of miRNA-mediated silencing mechanisms across 600 million years of animal evolution.

    PubMed

    Mauri, Marta; Kirchner, Marieluise; Aharoni, Reuven; Ciolli Mattioli, Camilla; van den Bruck, David; Gutkovitch, Nadya; Modepalli, Vengamanaidu; Selbach, Matthias; Moran, Yehu; Chekulaeva, Marina

    2017-01-25

    Our current knowledge about the mechanisms of miRNA silencing is restricted to few lineages such as vertebrates, arthropods, nematodes and land plants. miRNA-mediated silencing in bilaterian animals is dependent on the proteins of the GW182 family. Here, we dissect the function of GW182 protein in the cnidarian Nematostella, separated by 600 million years from other Metazoa. Using cultured human cells, we show that Nematostella GW182 recruits the CCR4-NOT deadenylation complexes via its tryptophan-containing motifs, thereby inhibiting translation and promoting mRNA decay. Further, similarly to bilaterians, GW182 in Nematostella is recruited to the miRNA repression complex via interaction with Argonaute proteins, and functions downstream to repress mRNA. Thus, our work suggests that this mechanism of miRNA-mediated silencing was already active in the last common ancestor of Cnidaria and Bilateria.

  11. Caribbean reef development was independent of coral diversity over 28 million years.

    PubMed

    Johnson, Kenneth G; Jackson, Jeremy B C; Budd, Ann F

    2008-03-14

    The relationship between natural variations in coral species diversity, reef development, and ecosystem function on coral reefs is poorly understood. Recent coral diversity varies 10-fold among geographic regions, but rates of reef growth are broadly similar, suggesting that diversity is unimportant for reef development. Differences in diversity may reflect regional differences in long-term biotic history in addition to environmental conditions. Using a combination of new and published fossil and stratigraphic data, we compared changes in coral diversity and reef development within the tropical western Atlantic over the past 28 million years. Reef development was unrelated to coral diversity, and the largest reef tracts formed after extinction had reduced diversity by 50%. High diversity is thus not essential for the growth and persistence of coral reefs.

  12. Brood care in a 100-million-year-old scale insect

    PubMed Central

    Wang, Bo; Xia, Fangyuan; Wappler, Torsten; Simon, Ewa; Zhang, Haichun; Jarzembowski, Edmund A; Szwedo, Jacek

    2015-01-01

    Behavior of extinct organisms can be inferred only indirectly, but occasionally rare fossils document particular behaviors directly. Brood care, a remarkable behavior promoting the survival of the next generation, has evolved independently numerous times among animals including insects. However, fossil evidence of such a complex behavior is exceptionally scarce. Here, we report an ensign scale insect (Hemiptera: Ortheziidae), Wathondara kotejai gen. et sp. nov., from mid-Cretaceous Burmese amber, which preserves eggs within a wax ovisac, and several freshly hatched nymphs. The new fossil is the only Mesozoic record of an adult female scale insect. More importantly, our finding represents the earliest unequivocal direct evidence of brood care in the insect fossil record and demonstrates a remarkably conserved egg-brooding reproductive strategy within scale insects in stasis for nearly 100 million years. DOI: http://dx.doi.org/10.7554/eLife.05447.001 PMID:25824055

  13. Marine extinction risk shaped by trait-environment interactions over 500 million years.

    PubMed

    Orzechowski, Emily A; Lockwood, Rowan; Byrnes, Jarrett E K; Anderson, Sean C; Finnegan, Seth; Finkel, Zoe V; Harnik, Paul G; Lindberg, David R; Liow, Lee Hsiang; Lotze, Heike K; McClain, Craig R; McGuire, Jenny L; O'Dea, Aaron; Pandolfi, John M; Simpson, Carl; Tittensor, Derek P

    2015-10-01

    Perhaps the most pressing issue in predicting biotic responses to present and future global change is understanding how environmental factors shape the relationship between ecological traits and extinction risk. The fossil record provides millions of years of insight into how extinction selectivity (i.e., differential extinction risk) is shaped by interactions between ecological traits and environmental conditions. Numerous paleontological studies have examined trait-based extinction selectivity; however, the extent to which these patterns are shaped by environmental conditions is poorly understood due to a lack of quantitative synthesis across studies. We conducted a meta-analysis of published studies on fossil marine bivalves and gastropods that span 458 million years to uncover how global environmental and geochemical changes covary with trait-based extinction selectivity. We focused on geographic range size and life habit (i.e., infaunal vs. epifaunal), two of the most important and commonly examined predictors of extinction selectivity. We used geochemical proxies related to global climate, as well as indicators of ocean acidification, to infer average global environmental conditions. Life-habit selectivity is weakly dependent on environmental conditions, with infaunal species relatively buffered from extinction during warmer climate states. In contrast, the odds of taxa with broad geographic ranges surviving an extinction (>2500 km for genera, >500 km for species) are on average three times greater than narrow-ranging taxa (estimate of odds ratio: 2.8, 95% confidence interval = 2.3-3.5), regardless of the prevailing global environmental conditions. The environmental independence of geographic range size extinction selectivity emphasizes the critical role of geographic range size in setting conservation priorities.

  14. State-dependent climate sensitivity of the last 5 million years

    NASA Astrophysics Data System (ADS)

    Köhler, Peter; de Boer, Bas; von der Heydt, Anna; Stap, Lennert; van de Wal, Roderik

    2015-04-01

    Equilibrium temperature rise in response to increase in radiative forcing is called equilibrium climate sensitivity, an important quantity calculated by climate models to project future warming. For model validation comparisons with estimates based on paleo reconstructions are necessary. Here we use an energy balance model (Köhler et al., 2010) to estimate climate sensitivity using CO2 proxy data together with model-based reconstruction of land ice (de Boer et al., 2014) over the last 5 million years. We find that equilibrium climate sensitivity containing the radiative forcing of CO2 and land ice albedo depends on the background climate. This state-dependency is mainly contained in the non-linearity of the land-ice forcing. Results differ in detail if based on ice core CO2 of the last 800,000 years covering mainly colder than present climates (von der Heydt et al., 2014) or on CO2 proxies of the last 5 million years. Nevertheless, the climate sensitivity of the warm Pliocene, a paleo-analogy for a warmer future, is at least about a third higher than for preindustrial background climates. References: de Boer, B., Lourens, L. J. & van de Wal, R. S. Persistent 400,000-year variability of Antarctic ice volume and the carbon cycle is revealed throughout the Plio-Pleistocene. Nature Communications 5, 2999 (2014). doi: 10.1038/ncomms3999. Köhler, P. Bintanja, R., Fischer, H., Joos, F., Knutti, R., Lohmann, G. & Masson-Delmotte, V. What caused Earth's temperature variations during the last 800,000 years? Data-based evidences on radiative forcing and constraints on climate sensitivity. Quaternary Science Reviews 29, 129-145 (2010). doi: 10.1016/j.quascirev.2009.09.026. von der Heydt, A. S., Köhler, P., van de Wal, R. S. & Dijkstra, H. A. On the state dependency of fast feedback processes in (paleo) climate sensitivity. Geophysical Research Letters 41, 6484-6492 (2014). doi: 10.1002/2014GL061121.

  15. Geomagnetic dipole strength and reversal rate over the past two million years.

    PubMed

    Valet, Jean-Pierre; Meynadier, Laure; Guyodo, Yohan

    2005-06-09

    Independent records of relative magnetic palaeointensity from sediment cores in different areas of the world can be stacked together to extract the evolution of the geomagnetic dipole moment and thus provide information regarding the processes governing the geodynamo. So far, this procedure has been limited to the past 800,000 years (800 kyr; ref. 3), which does not include any geomagnetic reversals. Here we present a composite curve that shows the evolution of the dipole moment during the past two million years. This reconstruction is in good agreement with the absolute dipole moments derived from volcanic lavas, which were used for calibration. We show that, at least during this period, the time-averaged field was higher during periods without reversals but the amplitude of the short-term oscillations remained the same. As a consequence, few intervals of very low intensity, and thus fewer instabilities, are expected during periods with a strong average dipole moment, whereas more excursions and reversals are expected during periods of weak field intensity. We also observe that the axial dipole begins to decay 60-80 kyr before reversals, but rebuilds itself in the opposite direction in only a few thousand years.

  16. Tobamoviruses have probably co-diverged with their eudicotyledonous hosts for at least 110 million years

    PubMed Central

    Gibbs, Adrian J.; Wood, Jeffrey; Garcia-Arenal, Fernando; Ohshima, Kazusato; Armstrong, John S.

    2015-01-01

    A phylogeny has been calculated by maximum likelihood comparisons of the concatenated consensus protein sequences of 29 tobamoviruses shown to be non-recombinant. This phylogeny has statistically significant support throughout, including its basal branches. The viruses form eight lineages that are congruent with the taxonomy of the hosts from which each was first isolated and, with the exception of three of the twenty-nine species, all fall into three clusters that have either asterid or rosid or caryophyllid hosts (i.e. the major subdivisions of eudicotyledonous plants). A modified Mantel permutation test showed that the patristic distances of virus and host phylogenies are significantly correlated, especially when the three anomalously placed viruses are removed. When the internal branches of the virus phylogeny were collapsed the congruence decreased. The simplest explanation of this congruence of the virus and host phylogenies is that most tobamovirus lineages have co-diverged with their primary plant hosts for more than 110 million years, and only the brassica-infecting lineage originated from a major host switch from asterids to rosids. Their co-divergence seems to have been ‘fuzzy’ rather than ‘strict’, permitting viruses to switch hosts within major host clades. Our conclusions support those of a coalesence analysis of tobamovirus sequences, that used proxy node dating, but not a similar analysis of nucleotide sequences from dated samples, which concluded that the tobamoviruses originated only 100 thousand years ago. PMID:27774289

  17. Early evolution of limb regeneration in tetrapods: evidence from a 300-million-year-old amphibian.

    PubMed

    Fröbisch, Nadia B; Bickelmann, Constanze; Witzmann, Florian

    2014-11-07

    Salamanders are the only tetrapods capable of fully regenerating their limbs throughout their entire lives. Much data on the underlying molecular mechanisms of limb regeneration have been gathered in recent years allowing for new comparative studies between salamanders and other tetrapods that lack this unique regenerative potential. By contrast, the evolution of animal regeneration just recently shifted back into focus, despite being highly relevant for research designs aiming to unravel the factors allowing for limb regeneration. We show that the 300-million-year-old temnospondyl amphibian Micromelerpeton, a distant relative of modern amphibians, was already capable of regenerating its limbs. A number of exceptionally well-preserved specimens from fossil deposits show a unique pattern and combination of abnormalities in their limbs that is distinctive of irregular regenerative activity in modern salamanders and does not occur as variants of normal limb development. This demonstrates that the capacity to regenerate limbs is not a derived feature of modern salamanders, but may be an ancient feature of non-amniote tetrapods and possibly even shared by all bony fish. The finding provides a new framework for understanding the evolution of regenerative capacity of paired appendages in vertebrates in the search for conserved versus derived molecular mechanisms of limb regeneration.

  18. A new estimate of average dipole field strength for the last five million years

    NASA Astrophysics Data System (ADS)

    Cromwell, G.; Tauxe, L.; Halldorsson, S. A.

    2013-12-01

    The Earth's ancient magnetic field can be approximated by a geocentric axial dipole (GAD) where the average field intensity is twice as strong at the poles than at the equator. The present day geomagnetic field, and some global paleointensity datasets, support the GAD hypothesis with a virtual axial dipole moment (VADM) of about 80 ZAm2. Significant departures from GAD for 0-5 Ma are found in Antarctica and Iceland where paleointensity experiments on massive flows (Antarctica) (1) and volcanic glasses (Iceland) produce average VADM estimates of 41.4 ZAm2 and 59.5 ZAm2, respectively. These combined intensities are much closer to a lower estimate for long-term dipole field strength, 50 ZAm2 (2), and some other estimates of average VADM based on paleointensities strictly from volcanic glasses. Proposed explanations for the observed non-GAD behavior, from otherwise high-quality paleointensity results, include incomplete temporal sampling, effects from the tangent cylinder, and hemispheric asymmetry. Differences in estimates of average magnetic field strength likely arise from inconsistent selection protocols and experiment methodologies. We address these possible biases and estimate the average dipole field strength for the last five million years by compiling measurement level data of IZZI-modified paleointensity experiments from lava flows around the globe (including new results from Iceland and the HSDP-2 Hawaii drill core). We use the Thellier Gui paleointensity interpreter (3) in order to apply objective criteria to all specimens, ensuring consistency between sites. Specimen level selection criteria are determined from a recent paleointensity investigation of modern Hawaiian lava flows where the expected magnetic field strength was accurately recovered when following certain selection parameters. Our new estimate of average dipole field strength for the last five million years incorporates multiple paleointensity studies on lava flows with diverse global and

  19. Regulatory Perspective on Implementation of a Dose Standard for a One-Million Year Compliance Period

    SciTech Connect

    McCartin, Timothy

    2007-07-01

    The disposal of high-level radioactive wastes in a potential geologic repository at Yucca Mountain, Nevada is governed by the U.S. Environmental Protection Agency (EPA) standards and U.S. Nuclear Regulatory Commission (NRC) regulations. The EPA has the responsibility for setting public health and safety and environmental standards for radioactive waste disposal at Yucca Mountain and it is the NRC's responsibility to implement those standards in its regulations to ensure public health and safety and the environment are protected. The U.S. Department of Energy (DOE), as the developer of the potential repository, must submit a license application to the NRC to seek approval to construct the repository. DOE must comply with NRC's regulations for NRC to authorize construction and license operation of a potential repository at Yucca Mountain. In 2005, EPA issued proposed revised standards and NRC issued proposed revised regulations for conducting performance assessment beyond 10,000 years up to 1 million years. The challenge for the EPA and NRC is to develop standards and regulations that provide an appropriate method for evaluating the safety of the potential repository given the unprecedented time period to be analyzed and the inherent uncertainties in estimating the future evolution of the Yucca Mountain site and the containment of the waste in the waste packages. A fundamental aspect of the proposed EPA standard is the specified approach for limiting undue speculation on future behavior of the site by constraining the features, events, and processes that need to be considered in the performance assessment. EPA proposed to limit the assessment of specific features, events, and processes in the period after 10,000 years to effects on the repository system that are most relevant (i.e., ignoring lesser or secondary effects that may add to speculation and uncertainties but would not be expected to have a significant effect on peak dose over a 1 million year period). For

  20. Evidence for a major meteorite impact on the earth 34 million years ago - Implication for Eocene extinctions

    NASA Astrophysics Data System (ADS)

    Ganapathy, R.

    1982-05-01

    A deep-sea core from the Caribbean contains a layer of sediment highly enriched in meteoritic iridium. This layer underlies a layer of North American microtekites dated at 34.4 million years ago and coincides with the extinction of five major species of Radiolaria. It is suggested that a massive, chemically undifferentiated meteorite collided with the earth, producing the tektites and leading to extinctions 34 millions years ago.

  1. Dinosaurs in decline tens of millions of years before their final extinction

    NASA Astrophysics Data System (ADS)

    Sakamoto, Manabu; Benton, Michael J.

    2016-05-01

    Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous-Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event.

  2. Dinosaurs in decline tens of millions of years before their final extinction.

    PubMed

    Sakamoto, Manabu; Benton, Michael J; Venditti, Chris

    2016-05-03

    Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous-Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event.

  3. Sufficient oxygen for animal respiration 1,400 million years ago.

    PubMed

    Zhang, Shuichang; Wang, Xiaomei; Wang, Huajian; Bjerrum, Christian J; Hammarlund, Emma U; Costa, M Mafalda; Connelly, James N; Zhang, Baomin; Su, Jin; Canfield, Donald E

    2016-02-16

    The Mesoproterozoic Eon [1,600-1,000 million years ago (Ma)] is emerging as a key interval in Earth history, with a unique geochemical history that might have influenced the course of biological evolution on Earth. Indeed, although this time interval is rather poorly understood, recent chromium isotope results suggest that atmospheric oxygen levels were <0.1% of present levels, sufficiently low to have inhibited the evolution of animal life. In contrast, using a different approach, we explore the distribution and enrichments of redox-sensitive trace metals in the 1,400 Ma sediments of Unit 3 of the Xiamaling Formation, North China Block. Patterns of trace metal enrichments reveal oxygenated bottom waters during deposition of the sediments, and biomarker results demonstrate the presence of green sulfur bacteria in the water column. Thus, we document an ancient oxygen minimum zone. We develop a simple, yet comprehensive, model of marine carbon-oxygen cycle dynamics to show that our geochemical results are consistent with atmospheric oxygen levels >4% of present-day levels. Therefore, in contrast to previous suggestions, we show that there was sufficient oxygen to fuel animal respiration long before the evolution of animals themselves.

  4. A new glimpse on Mesozoic zooplankton-150 million-year-old lobster larvae.

    PubMed

    Haug, Joachim T; Haug, Carolin

    2017-01-01

    Larvae of malacostracan crustaceans represent a large fraction of modern day zooplankton. Plankton is not only a major part of the modern marine ecosystem, but must have played an important role in the ecosystems of the past as well. Unfortunately, our knowledge about plankton composition of the past is still quite limited. As an important part of today's zooplankton, malacostracan larvae are still a rarity in the fossil record; many types of malacostracan larvae dominating the modern plankton have so far not been found as fossils. Here we report a new type of fossil malacostracan larva, found in the 150 million years old lithographic limestones of southern Germany (Solnhofen Lithographic Limestones). The three rather incomplete specimens mainly preserve the telson. A pronounced middle spine on the posterior edge of these specimens indicates that they are either larval forms of a clawed lobster or of an axiidean lobster, or of a closer relative to one of the two groups. The tergo-pleura are drawn out into distinct spines in one specimen, further supporting the interpretation as a larva of a clawed lobster or an early relative. The telson morphology also shows adaptations to a prolonged planktic life style, the latero-posterior edges are drawn out into distinct spines. Similar adaptations are known in larvae of the modern homarid lobster Nephrops norvegicus, not necessarily indicating a closer relationship, but convergent life styles. The new finds provide an important new insight into the composition of Mesozoic zooplankton and demonstrate the preservation potential of lithographic limestones.

  5. Continuous exhumation of mantle-derived rocks at the Southwest Indian Ridge for 11 million years

    NASA Astrophysics Data System (ADS)

    Sauter, Daniel; Cannat, Mathilde; Rouméjon, Stéphane; Andreani, Muriel; Birot, Dominique; Bronner, Adrien; Brunelli, Daniele; Carlut, Julie; Delacour, Adélie; Guyader, Vivien; MacLeod, Christopher J.; Manatschal, Gianreto; Mendel, Véronique; Ménez, Bénédicte; Pasini, Valerio; Ruellan, Etienne; Searle, Roger

    2013-04-01

    The global mid-ocean ridge system, where tectonic plates diverge, is traditionally thought of as the largest single volcanic feature on the Earth. Yet, wide expanses of smooth sea floor in the easternmost part of the Southwest Indian Ridge in the Indian Ocean lacks the hummocky morphology that is typical for submarine volcanism. At other slow-spreading ridges, the sea floor can extend by faulting the existing lithosphere, along only one side of the ridge axis. However, the smooth sea floor in the easternmost Southwest Indian Ridge also lacks the corrugated texture created by such faulting. Instead, the sea floor is smooth on both sides of the ridge axis and is thought to be composed of altered mantle-derived rocks. Here we use side-scan sonar to image the sea floor and dredge samples to analyse the composition of two sections of the Southwest Indian Ridge, between 62°05'E and 64°40'E, where the sea floor formed over the past 11 million years. We show that the smooth floor is almost entirely composed of seawater-altered mantle-derived rocks that were brought to the surface by large detachment faults on both sides of the ridge axis. Faulting accommodates almost 100% of plate divergence and the detachment faults have repeatedly flipped polarity. We suggest that this tectonic process could also explain the exhumation of mantle-derived rocks at the magma-poor margins of rifted continents.

  6. Developmental gene regulatory network architecture across 500 million years of echinoderm evolution

    NASA Technical Reports Server (NTRS)

    Hinman, Veronica F.; Nguyen, Albert T.; Cameron, R. Andrew; Davidson, Eric H.

    2003-01-01

    Evolutionary change in morphological features must depend on architectural reorganization of developmental gene regulatory networks (GRNs), just as true conservation of morphological features must imply retention of ancestral developmental GRN features. Key elements of the provisional GRN for embryonic endomesoderm development in the sea urchin are here compared with those operating in embryos of a distantly related echinoderm, a starfish. These animals diverged from their common ancestor 520-480 million years ago. Their endomesodermal fate maps are similar, except that sea urchins generate a skeletogenic cell lineage that produces a prominent skeleton lacking entirely in starfish larvae. A relevant set of regulatory genes was isolated from the starfish Asterina miniata, their expression patterns determined, and effects on the other genes of perturbing the expression of each were demonstrated. A three-gene feedback loop that is a fundamental feature of the sea urchin GRN for endoderm specification is found in almost identical form in the starfish: a detailed element of GRN architecture has been retained since the Cambrian Period in both echinoderm lineages. The significance of this retention is highlighted by the observation of numerous specific differences in the GRN connections as well. A regulatory gene used to drive skeletogenesis in the sea urchin is used entirely differently in the starfish, where it responds to endomesodermal inputs that do not affect it in the sea urchin embryo. Evolutionary changes in the GRNs since divergence are limited sharply to certain cis-regulatory elements, whereas others have persisted unaltered.

  7. Confocal scanning optical microscopy of a 3-million-year-old Australopithecus afarensis femur.

    PubMed

    Bromage, T G; Goldman, H M; McFarlin, S C; Perez Ochoa, A; Boyde, A

    2009-01-01

    Portable confocal scanning optical microscopy (PCSOM) has been specifically developed for the noncontact and nondestructive imaging of early human fossil hard tissues, which here we describe and apply to a 3-million-year-old femur from the celebrated Ethiopian skeleton, "Lucy," referred to Australopithecus afarensis. We examine two bone tissue parameters that demonstrate the potential of this technology. First, subsurface reflection images from intact bone reveal bone cell spaces, the osteocyte lacunae, whose density is demonstrated to scale negatively with body size, reflecting aspects of metabolism and organismal life history. Second, images of a naturally fractured cross section near to Lucy's femoral mid-shaft, which match in sign those of transmitted circularly polarized light, reveal relative collagen fiber orientation patterns that are an important indicator of femoral biomechanical efficacy. Preliminary results indicate that Lucy was characterized by metabolic constraints typical for a primate her body size and that in her femur she was adapted to habitual bipedalism. Limitations imposed by the transport and invasive histology of unique or rare fossils motivated development of the PCSOM so that specimens may be examined wherever and whenever nondestructive imaging is required.

  8. One million years of glaciation and denudation history in west Greenland

    NASA Astrophysics Data System (ADS)

    Strunk, Astrid; Knudsen, Mads Faurschou; Egholm, David L.; Jansen, John D.; Levy, Laura B.; Jacobsen, Bo H.; Larsen, Nicolaj K.

    2017-01-01

    The influence of major Quaternary climatic changes on growth and decay of the Greenland Ice Sheet, and associated erosional impact on the landscapes, is virtually unknown beyond the last deglaciation. Here we quantify exposure and denudation histories in west Greenland by applying a novel Markov-Chain Monte Carlo modelling approach to all available paired cosmogenic 10Be-26Al bedrock data from Greenland. We find that long-term denudation rates in west Greenland range from >50 m Myr-1 in low-lying areas to ~2 m Myr-1 at high elevations, hereby quantifying systematic variations in denudation rate among different glacial landforms caused by variations in ice thickness across the landscape. We furthermore show that the present day ice-free areas only were ice covered ca. 45% of the past 1 million years, and even less at high-elevation sites, implying that the Greenland Ice Sheet for much of the time was of similar size or even smaller than today.

  9. Terrestrial climate evolution in the Southwest Pacific over the past 30 million years

    NASA Astrophysics Data System (ADS)

    Prebble, Joseph G.; Reichgelt, Tammo; Mildenhall, Dallas C.; Greenwood, David R.; Raine, J. Ian; Kennedy, Elizabeth M.; Seebeck, Hannu C.

    2017-02-01

    A reconstruction of terrestrial temperature and precipitation for the New Zealand landmass over the past ∼30 million years is produced using pollen data from >2000 samples lodged in the New Zealand Fossil Record Electronic Database and modern climate data of nearest living relatives. The reconstruction reveals a warming trend through the late Oligocene to early Miocene, peak warmth in the middle Miocene, and stepwise cooling through the late Neogene. Whereas the regional signal in our reconstruction includes a ∼5-10° northward tectonic drift, as well as an increase in high altitude biomes due to late Neogene and Pliocene uplift of the Southern Alps, the pattern mimics inferred changes in global ice extent, which suggests that global drivers played a major role in shaping local vegetation. Importantly, seasonal temperature estimates indicate low seasonality during the middle Miocene, and that subsequent Neogene cooling was largely due to cooler winters. We suggest that this may reflect increased Subantarctic influence on New Zealand vegetation as the climate cooled.

  10. One million years of glaciation and denudation history in west Greenland

    PubMed Central

    Strunk, Astrid; Knudsen, Mads Faurschou; Egholm, David L.; Jansen, John D.; Levy, Laura B.; Jacobsen, Bo H.; Larsen, Nicolaj K.

    2017-01-01

    The influence of major Quaternary climatic changes on growth and decay of the Greenland Ice Sheet, and associated erosional impact on the landscapes, is virtually unknown beyond the last deglaciation. Here we quantify exposure and denudation histories in west Greenland by applying a novel Markov-Chain Monte Carlo modelling approach to all available paired cosmogenic 10Be-26Al bedrock data from Greenland. We find that long-term denudation rates in west Greenland range from >50 m Myr−1 in low-lying areas to ∼2 m Myr−1 at high elevations, hereby quantifying systematic variations in denudation rate among different glacial landforms caused by variations in ice thickness across the landscape. We furthermore show that the present day ice-free areas only were ice covered ca. 45% of the past 1 million years, and even less at high-elevation sites, implying that the Greenland Ice Sheet for much of the time was of similar size or even smaller than today. PMID:28098141

  11. Iridium profile for 10 million years across the Cretaceous-Tertiary boundary at Gubbio (Italy)

    NASA Technical Reports Server (NTRS)

    Alvarez, Walter; Asaro, Frank; Montanari, Alessandro

    1990-01-01

    The iridium anomaly at the Cretaceous-Tertiary (KT) boundary was discovered in the pelagic limestone sequence at Gubbio on the basis of 12 samples analyzed by neutron activation analysis (NAA) and was interpreted as indicating impact of a large extraterrestrial object at exactly the time of the KT mass extinction. Continuing controversy over the shape of the Ir profile at the Gubbio KT boundary and its interpretation called for a more detailed follow-up study. Analysis of a 57-meter-thick, 10-million-year-old part of the Gubbio sequence using improved NAA techniques revealed that there is only one Ir anomaly at the KT boundary, but this anomaly shows an intricate fine structure, the origin of which cannot yet be entirely explained. The KT Ir anomaly peaks in a 1-centimeter-thick clay layer, where the average Ir concentration is 3000 parts per trillion (ppt); this peak is flanked by tails with Ir concentrations of 20 to 80 ppt that rise above a background of 12 to 13 ppt. The fine structure of the tails is probably due in part to lateral reworking, diffusion, burrowing, and perhaps Milankovitch cyclicity.

  12. Developmental gene regulatory network architecture across 500 million years of echinoderm evolution.

    PubMed

    Hinman, Veronica F; Nguyen, Albert T; Cameron, R Andrew; Davidson, Eric H

    2003-11-11

    Evolutionary change in morphological features must depend on architectural reorganization of developmental gene regulatory networks (GRNs), just as true conservation of morphological features must imply retention of ancestral developmental GRN features. Key elements of the provisional GRN for embryonic endomesoderm development in the sea urchin are here compared with those operating in embryos of a distantly related echinoderm, a starfish. These animals diverged from their common ancestor 520-480 million years ago. Their endomesodermal fate maps are similar, except that sea urchins generate a skeletogenic cell lineage that produces a prominent skeleton lacking entirely in starfish larvae. A relevant set of regulatory genes was isolated from the starfish Asterina miniata, their expression patterns determined, and effects on the other genes of perturbing the expression of each were demonstrated. A three-gene feedback loop that is a fundamental feature of the sea urchin GRN for endoderm specification is found in almost identical form in the starfish: a detailed element of GRN architecture has been retained since the Cambrian Period in both echinoderm lineages. The significance of this retention is highlighted by the observation of numerous specific differences in the GRN connections as well. A regulatory gene used to drive skeletogenesis in the sea urchin is used entirely differently in the starfish, where it responds to endomesodermal inputs that do not affect it in the sea urchin embryo. Evolutionary changes in the GRNs since divergence are limited sharply to certain cis-regulatory elements, whereas others have persisted unaltered.

  13. Dinosaurs in decline tens of millions of years before their final extinction

    PubMed Central

    Sakamoto, Manabu; Benton, Michael J.; Venditti, Chris

    2016-01-01

    Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous–Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event. PMID:27092007

  14. Rapid evolution of the most luminous galaxies during the first 900 million years.

    PubMed

    Bouwens, Rychard J; Illingworth, Garth D

    2006-09-14

    The first 900 million years (Myr) to redshift z approximately 6 (the first seven per cent of the age of the Universe) remains largely unexplored for the formation of galaxies. Large samples of galaxies have been found at z approximately 6 (refs 1-4) but detections at earlier times are uncertain and unreliable. It is not at all clear how galaxies built up from the first stars when the Universe was about 300 Myr old (z approximately 12-15) to z approximately 6, just 600 Myr later. Here we report the results of a search for galaxies at z approximately 7-8, about 700 Myr after the Big Bang, using the deepest near-infrared and optical images ever taken. Under conservative selection criteria we find only one candidate galaxy at z approximately 7-8, where ten would be expected if there were no evolution in the galaxy population between z approximately 7-8 and z approximately 6. Using less conservative criteria, there are four candidates, where 17 would be expected with no evolution. This demonstrates that very luminous galaxies are quite rare 700 Myr after the Big Bang. The simplest explanation is that the Universe is just too young to have built up many luminous galaxies at z approximately 7-8 by the hierarchical merging of small galaxies.

  15. Cross-Amplification and Validation of SNPs Conserved over 44 Million Years between Seals and Dogs

    PubMed Central

    Hoffman, Joseph I.; Thorne, Michael A. S.; McEwing, Rob; Forcada, Jaume; Ogden, Rob

    2013-01-01

    High-density SNP arrays developed for humans and their companion species provide a rapid and convenient tool for generating SNP data in closely-related non-model organisms, but have not yet been widely applied to phylogenetically divergent taxa. Consequently, we used the CanineHD BeadChip to genotype 24 Antarctic fur seal (Arctocephalus gazella) individuals. Despite seals and dogs having diverged around 44 million years ago, 33,324 out of 173,662 loci (19.2%) could be genotyped, of which 173 were polymorphic and clearly interpretable. Two SNPs were validated using KASP genotyping assays, with the resulting genotypes being 100% concordant with those obtained from the high-density array. Two loci were also confirmed through in silico visualisation after mapping them to the fur seal transcriptome. Polymorphic SNPs were distributed broadly throughout the dog genome and did not differ significantly in proximity to genes from either monomorphic SNPs or those that failed to cross-amplify in seals. However, the nearest genes to polymorphic SNPs were significantly enriched for functional annotations relating to energy metabolism, suggesting a possible bias towards conserved regions of the genome. PMID:23874599

  16. Burrowing hard corals occurring on the sea floor since 80 million years ago.

    PubMed

    Sentoku, Asuka; Tokuda, Yuki; Ezaki, Yoichi

    2016-04-14

    We describe a previously unknown niche for hard corals in the small, bowl-shaped, solitary scleractinian, Deltocyathoides orientalis (Family Turbinoliidae), on soft-bottom substrates. Observational experiments were used to clarify how the sea floor niche is exploited by turbinoliids. Deltocyathoides orientalis is adapted to an infaunal mode of life and exhibits behaviours associated with automobility that include burrowing into sediments, vertical movement through sediments to escape burial, and recovery of an upright position after being overturned. These behaviours were achieved through repeated expansion and contraction of their peripheral soft tissues, which constitute a unique muscle-membrane system. Histological analysis showed that these muscle arrangements were associated with deeply incised inter-costal spaces characteristic of turbinoliid corals. The oldest known turbinoliid, Bothrophoria ornata, which occurred in the Cretaceous (Campanian), also possessed a small, conical skeleton with highly developed costae. An infaunal mode of life became available to turbinoliids due to the acquisition of automobility through the muscle-membrane system at least 80 million years ago. The newly discovered active burrowing strategies described herein provide new insights into the use of an unattached mode of life by corals inhabiting soft-bottom substrates throughout the Phanerozoic.

  17. Iridium profile for 10 million years across the Cretaceous-Tertiary boundary at Gubbio (Italy).

    PubMed

    Alvarez, W; Asaro, F; Montanari, A

    1990-12-21

    The iridium anomaly at the Cretaceous-Tertiary (KT) boundary was discovered in the pelagic limestone sequence at Gubbio on the basis of 12 samples analyzed by neutron activation analysis (NAA) and was interpreted as indicating impact of a large extraterrestrial object at exactly the time of the KT mass extinction. Continuing controversy over the shape of the Ir profile at the Gubbio KT boundary and its interpretation called for a more detailed follow-up study. Analysis of a 57-meter-thick, 10-million-year-old part of the Gubbio sequence using improved NAA techniques revealed that there is only one Ir anomaly at the KT boundary, but this anomaly shows an intricate fine structure, the origin of which cannot yet be entirely explained. The KT Ir anomaly peaks in a 1-centimeter-thick clay layer, where average Ir concentration is 3000 parts per trillion (ppt); this peak is flanked by tails with Ir concentrations of 20 to 80 ppt that rise above a background of 12 to 13 ppt. The fine structure of the tails is probably due in part to lateral reworking, diffusion, burrowing, and perhaps Milankovitch cyclicity.

  18. Sufficient oxygen for animal respiration 1,400 million years ago

    PubMed Central

    Zhang, Shuichang; Wang, Xiaomei; Wang, Huajian; Bjerrum, Christian J.; Hammarlund, Emma U.; Costa, M. Mafalda; Connelly, James N.; Zhang, Baomin; Su, Jin; Canfield, Donald E.

    2016-01-01

    The Mesoproterozoic Eon [1,600–1,000 million years ago (Ma)] is emerging as a key interval in Earth history, with a unique geochemical history that might have influenced the course of biological evolution on Earth. Indeed, although this time interval is rather poorly understood, recent chromium isotope results suggest that atmospheric oxygen levels were <0.1% of present levels, sufficiently low to have inhibited the evolution of animal life. In contrast, using a different approach, we explore the distribution and enrichments of redox-sensitive trace metals in the 1,400 Ma sediments of Unit 3 of the Xiamaling Formation, North China Block. Patterns of trace metal enrichments reveal oxygenated bottom waters during deposition of the sediments, and biomarker results demonstrate the presence of green sulfur bacteria in the water column. Thus, we document an ancient oxygen minimum zone. We develop a simple, yet comprehensive, model of marine carbon−oxygen cycle dynamics to show that our geochemical results are consistent with atmospheric oxygen levels >4% of present-day levels. Therefore, in contrast to previous suggestions, we show that there was sufficient oxygen to fuel animal respiration long before the evolution of animals themselves. PMID:26729865

  19. Marine and terrestrial herbivores display convergent chemical ecology despite 400 million years of independent evolution.

    PubMed

    Rasher, Douglas B; Stout, E Paige; Engel, Sebastian; Shearer, Tonya L; Kubanek, Julia; Hay, Mark E

    2015-09-29

    Chemical cues regulate key ecological interactions in marine and terrestrial ecosystems. They are particularly important in terrestrial plant-herbivore interactions, where they mediate both herbivore foraging and plant defense. Although well described for terrestrial interactions, the identity and ecological importance of herbivore foraging cues in marine ecosystems remain unknown. Here we show that the specialist gastropod Elysia tuca hunts its seaweed prey, Halimeda incrassata, by tracking 4-hydroxybenzoic acid to find vegetative prey and the defensive metabolite halimedatetraacetate to find reproductive prey. Foraging cues were predicted to be polar compounds but instead were nonpolar secondary metabolites similar to those used by specialist terrestrial insects. Tracking halimedatetraacetate enables Elysia to increase in abundance by 12- to 18-fold on reproductive Halimeda, despite reproduction in Halimeda being rare and lasting for only ∼36 h. Elysia swarm to reproductive Halimeda where they consume the alga's gametes, which are resource rich but are chemically defended from most consumers. Elysia sequester functional chloroplasts and halimedatetraacetate from Halimeda to become photosynthetic and chemically defended. Feeding by Elysia suppresses the growth of vegetative Halimeda by ∼50%. Halimeda responds by dropping branches occupied by Elysia, apparently to prevent fungal infection associated with Elysia feeding. Elysia is remarkably similar to some terrestrial insects, not only in its hunting strategy, but also its feeding method, defense tactics, and effects on prey behavior and performance. Such striking parallels indicate that specialist herbivores in marine and terrestrial systems can evolve convergent ecological strategies despite 400 million years of independent evolution in vastly different habitats.

  20. Burrowing hard corals occurring on the sea floor since 80 million years ago

    PubMed Central

    Sentoku, Asuka; Tokuda, Yuki; Ezaki, Yoichi

    2016-01-01

    We describe a previously unknown niche for hard corals in the small, bowl-shaped, solitary scleractinian, Deltocyathoides orientalis (Family Turbinoliidae), on soft-bottom substrates. Observational experiments were used to clarify how the sea floor niche is exploited by turbinoliids. Deltocyathoides orientalis is adapted to an infaunal mode of life and exhibits behaviours associated with automobility that include burrowing into sediments, vertical movement through sediments to escape burial, and recovery of an upright position after being overturned. These behaviours were achieved through repeated expansion and contraction of their peripheral soft tissues, which constitute a unique muscle-membrane system. Histological analysis showed that these muscle arrangements were associated with deeply incised inter-costal spaces characteristic of turbinoliid corals. The oldest known turbinoliid, Bothrophoria ornata, which occurred in the Cretaceous (Campanian), also possessed a small, conical skeleton with highly developed costae. An infaunal mode of life became available to turbinoliids due to the acquisition of automobility through the muscle-membrane system at least 80 million years ago. The newly discovered active burrowing strategies described herein provide new insights into the use of an unattached mode of life by corals inhabiting soft-bottom substrates throughout the Phanerozoic. PMID:27074813

  1. Gene copy number variation spanning 60 million years of human and primate evolution

    PubMed Central

    Dumas, Laura; Kim, Young H.; Karimpour-Fard, Anis; Cox, Michael; Hopkins, Janet; Pollack, Jonathan R.; Sikela, James M.

    2007-01-01

    Given the evolutionary importance of gene duplication to the emergence of species-specific traits, we have extended the application of cDNA array-based comparative genomic hybridization (aCGH) to survey gene duplications and losses genome-wide across 10 primate species, including human. Using human cDNA arrays that contained 41,126 cDNAs, corresponding to 24,473 unique human genes, we identified 4159 genes that likely represent most of the major lineage-specific gene copy number gains and losses that have occurred in these species over the past 60 million years. We analyzed 1,233,780 gene-to-gene data points and found that gene gains typically outnumbered losses (ratio of gains/losses = 2.34) and these frequently cluster in complex and dynamic genomic regions that are likely to serve as gene nurseries. Almost one-third of all human genes (6696) exhibit an aCGH- predicted change in copy number in one or more of these species, and within-species gene amplification is also evident. Many of the genes identified here are likely to be important to lineage-specific traits including, for example, human-specific duplications of the AQP7 gene, which represent intriguing candidates to underlie the key physiological adaptations in thermoregulation and energy utilization that permitted human endurance running. PMID:17666543

  2. Tightly linked zonal and meridional sea surface temperature gradients over the past five million years

    NASA Astrophysics Data System (ADS)

    Fedorov, Alexey V.; Burls, Natalie J.; Lawrence, Kira T.; Peterson, Laura C.

    2015-12-01

    The climate of the tropics and surrounding regions is defined by pronounced zonal (east-west) and meridional (equator to mid-latitudes) gradients in sea surface temperature. These gradients control zonal and meridional atmospheric circulations, and thus the Earth’s climate. Global cooling over the past five million years, since the early Pliocene epoch, was accompanied by the gradual strengthening of these temperature gradients. Here we use records from the Atlantic and Pacific oceans, including a new alkenone palaeotemperature record from the South Pacific, to reconstruct changes in zonal and meridional sea surface temperature gradients since the Pliocene, and assess their connection using a comprehensive climate model. We find that the reconstructed zonal and meridional temperature gradients vary coherently over this time frame, showing a one-to-one relationship between their changes. In our model simulations, we systematically reduce the meridional sea surface temperature gradient by modifying the latitudinal distribution of cloud albedo or atmospheric CO2 concentration. The simulated zonal temperature gradient in the equatorial Pacific adjusts proportionally. These experiments and idealized modelling indicate that the meridional temperature gradient controls upper-ocean stratification in the tropics, which in turn controls the zonal gradient along the equator, as well as heat export from the tropical oceans. We conclude that this tight linkage between the two sea surface temperature gradients posits a fundamental constraint on both past and future climates.

  3. 70 million years of coastal upwelling in California; source rocks and paleoceanography

    SciTech Connect

    Fonseca, C. )

    1996-01-01

    The Late Mesozoic-Cenozoic marine sequence of California displays a unique record of coastal upwelling and productivity in the form of distinctive diatomaceous and organic-rich deposits including the upper Cretaceous-lower Paleocene Moreno Formation, the Eocene Kreyenhagen Formation and the Miocene Monterey Formation. Unique sedimentological characteristics of these ancient upwelling systems include (a) Finely laminated biosiliceous-rich shales (>30% biogenic silica content), (b) Distinctive laminae composed by monospecific diatom resting spores, (c) Good source rock quality (>300 mg HC/mg org C), and (d) High accumulation rates in mid water anoxic conditions. Detailed study of individual laminae in sediments of these formations revealed concentration of monospecific diatom resting spores and an abundance of Stephanopyxis sp. and Coscinodiscus sp. Like Recent upwelling systems, preserved laminations of monospecific resting spores reflect strong seasonal upwelling that lead to high organic matter production and enhancement of anoxia. The presence of spores in the ancient and modern upwelling systems is evidence that diatoms have adapted and successfully competed in the highly productive California Margin since the Late Cretaceous. The Moreno, the Kreyenhagen and the Monterey Formation account for a significant portion of major petroleum source beds in California and contain an important record of coastal upwelling and paleoceanographic change in the northeastern Pacific Ocean over the past 70 million years. It is suggested that potential Late Maestrichtian source rocks could have been deposited along other favorable upwelling areas of the Eastern Pacific Rim.

  4. Iterative evolution of sympatric seacow (Dugongidae, Sirenia) assemblages during the past ~26 million years.

    PubMed

    Velez-Juarbe, Jorge; Domning, Daryl P; Pyenson, Nicholas D

    2012-01-01

    Extant sirenians show allopatric distributions throughout most of their range. However, their fossil record shows evidence of multispecies communities throughout most of the past ∼26 million years, in different oceanic basins. Morphological differences among co-occurring sirenian taxa suggest that resource partitioning played a role in structuring these communities. We examined body size and ecomorphological differences (e.g., rostral deflection and tusk morphology) among sirenian assemblages from the late Oligocene of Florida, early Miocene of India and early Pliocene of Mexico; each with three species of the family Dugongidae. Although overlapping in several ecomorphological traits, each assemblage showed at least one dominant trait in which coexisting species differed. Fossil sirenian occurrences occasionally are monotypic, but the assemblages analyzed herein show iterative evolution of multispecies communities, a phenomenon unparalleled in extant sirenian ecology. As primary consumers of seagrasses, these communities likely had a strong impact on past seagrass ecology and diversity, although the sparse fossil record of seagrasses limits direct comparisons. Nonetheless, our results provide robust support for previous suggestions that some sirenians in these extinct assemblages served as keystone species, controlling the dominance of climax seagrass species, permitting more taxonomically diverse seagrass beds (and sirenian communities) than many of those observed today.

  5. Burrowing hard corals occurring on the sea floor since 80 million years ago

    NASA Astrophysics Data System (ADS)

    Sentoku, Asuka; Tokuda, Yuki; Ezaki, Yoichi

    2016-04-01

    We describe a previously unknown niche for hard corals in the small, bowl-shaped, solitary scleractinian, Deltocyathoides orientalis (Family Turbinoliidae), on soft-bottom substrates. Observational experiments were used to clarify how the sea floor niche is exploited by turbinoliids. Deltocyathoides orientalis is adapted to an infaunal mode of life and exhibits behaviours associated with automobility that include burrowing into sediments, vertical movement through sediments to escape burial, and recovery of an upright position after being overturned. These behaviours were achieved through repeated expansion and contraction of their peripheral soft tissues, which constitute a unique muscle-membrane system. Histological analysis showed that these muscle arrangements were associated with deeply incised inter-costal spaces characteristic of turbinoliid corals. The oldest known turbinoliid, Bothrophoria ornata, which occurred in the Cretaceous (Campanian), also possessed a small, conical skeleton with highly developed costae. An infaunal mode of life became available to turbinoliids due to the acquisition of automobility through the muscle-membrane system at least 80 million years ago. The newly discovered active burrowing strategies described herein provide new insights into the use of an unattached mode of life by corals inhabiting soft-bottom substrates throughout the Phanerozoic.

  6. Modelling West Antarctic ice sheet growth and collapse through the past five million years.

    PubMed

    Pollard, David; DeConto, Robert M

    2009-03-19

    The West Antarctic ice sheet (WAIS), with ice volume equivalent to approximately 5 m of sea level, has long been considered capable of past and future catastrophic collapse. Today, the ice sheet is fringed by vulnerable floating ice shelves that buttress the fast flow of inland ice streams. Grounding lines are several hundred metres below sea level and the bed deepens upstream, raising the prospect of runaway retreat. Projections of future WAIS behaviour have been hampered by limited understanding of past variations and their underlying forcing mechanisms. Its variation since the Last Glacial Maximum is best known, with grounding lines advancing to the continental-shelf edges around approximately 15 kyr ago before retreating to near-modern locations by approximately 3 kyr ago. Prior collapses during the warmth of the early Pliocene epoch and some Pleistocene interglacials have been suggested indirectly from records of sea level and deep-sea-core isotopes, and by the discovery of open-ocean diatoms in subglacial sediments. Until now, however, little direct evidence of such behaviour has been available. Here we use a combined ice sheet/ice shelf model capable of high-resolution nesting with a new treatment of grounding-line dynamics and ice-shelf buttressing to simulate Antarctic ice sheet variations over the past five million years. Modelled WAIS variations range from full glacial extents with grounding lines near the continental shelf break, intermediate states similar to modern, and brief but dramatic retreats, leaving only small, isolated ice caps on West Antarctic islands. Transitions between glacial, intermediate and collapsed states are relatively rapid, taking one to several thousand years. Our simulation is in good agreement with a new sediment record (ANDRILL AND-1B) recovered from the western Ross Sea, indicating a long-term trend from more frequently collapsed to more glaciated states, dominant 40-kyr cyclicity in the Pliocene, and major retreats at

  7. Baseline intrinsic flammability of Earth's ecosystems estimated from paleoatmospheric oxygen over the past 350 million years.

    PubMed

    Belcher, Claire M; Yearsley, Jonathan M; Hadden, Rory M; McElwain, Jennifer C; Rein, Guillermo

    2010-12-28

    Atmospheric oxygen (O(2)) is estimated to have varied greatly throughout Earth's history and has been capable of influencing wildfire activity wherever fuel and ignition sources were present. Fires consume huge quantities of biomass in all ecosystems and play an important role in biogeochemical cycles. This means that understanding the influence of O(2) on past fire activity has far-reaching consequences for the evolution of life and Earth's biodiversity over geological timescales. We have used a strong electrical ignition source to ignite smoldering fires, and we measured their self-sustaining propagation in atmospheres of different oxygen concentrations. These data have been used to build a model that we use to estimate the baseline intrinsic flammability of Earth's ecosystems according to variations in O(2) over the past 350 million years (Ma). Our aim is to highlight times in Earth's history when fire has been capable of influencing the Earth system. We reveal that fire activity would be greatly suppressed below 18.5% O(2), entirely switched off below 16% O(2), and rapidly enhanced between 19-22% O(2). We show that fire activity and, therefore, its influence on the Earth system would have been high during the Carboniferous (350-300 Ma) and Cretaceous (145-65 Ma) periods; intermediate in the Permian (299-251 Ma), Late Triassic (285-201 Ma), and Jurassic (201-145 Ma) periods; and surprisingly low to lacking in the Early-Middle Triassic period between 250-240 Ma. These baseline variations in Earth's flammability must be factored into our understanding of past vegetation, biodiversity, evolution, and biogeochemical cycles.

  8. A new glimpse on Mesozoic zooplankton—150 million-year-old lobster larvae

    PubMed Central

    Haug, Carolin

    2017-01-01

    Larvae of malacostracan crustaceans represent a large fraction of modern day zooplankton. Plankton is not only a major part of the modern marine ecosystem, but must have played an important role in the ecosystems of the past as well. Unfortunately, our knowledge about plankton composition of the past is still quite limited. As an important part of today’s zooplankton, malacostracan larvae are still a rarity in the fossil record; many types of malacostracan larvae dominating the modern plankton have so far not been found as fossils. Here we report a new type of fossil malacostracan larva, found in the 150 million years old lithographic limestones of southern Germany (Solnhofen Lithographic Limestones). The three rather incomplete specimens mainly preserve the telson. A pronounced middle spine on the posterior edge of these specimens indicates that they are either larval forms of a clawed lobster or of an axiidean lobster, or of a closer relative to one of the two groups. The tergo-pleura are drawn out into distinct spines in one specimen, further supporting the interpretation as a larva of a clawed lobster or an early relative. The telson morphology also shows adaptations to a prolonged planktic life style, the latero-posterior edges are drawn out into distinct spines. Similar adaptations are known in larvae of the modern homarid lobster Nephrops norvegicus, not necessarily indicating a closer relationship, but convergent life styles. The new finds provide an important new insight into the composition of Mesozoic zooplankton and demonstrate the preservation potential of lithographic limestones. PMID:28168123

  9. Conserved form and function of the germinal epithelium through 500 million years of vertebrate evolution.

    PubMed

    Grier, Harry J; Uribe, Mari Carmen; Lo Nostro, Fabiana L; Mims, Steven D; Parenti, Lynne R

    2016-08-01

    The germinal epithelium, i.e., the site of germ cell production in males and females, has maintained a constant form and function throughout 500 million years of vertebrate evolution. The distinguishing characteristic of germinal epithelia among all vertebrates, males, and females, is the presence of germ cells among somatic epithelial cells. The somatic epithelial cells, Sertoli cells in males or follicle (granulosa) cells in females, encompass and isolate germ cells. Morphology of all vertebrate germinal epithelia conforms to the standard definition of an epithelium: epithelial cells are interconnected, border a body surface or lumen, are avascular and are supported by a basement membrane. Variation in morphology of gonads, which develop from the germinal epithelium, is correlated with the evolution of reproductive modes. In hagfishes, lampreys, and elasmobranchs, the germinal epithelia of males produce spermatocysts. A major rearrangement of testis morphology diagnoses osteichthyans: the spermatocysts are arranged in tubules or lobules. In protogynous (female to male) sex reversal in teleost fishes, female germinal epithelial cells (prefollicle cells) and oogonia transform into the first male somatic cells (Sertoli cells) and spermatogonia in the developing testis lobules. This common origin of cell types from the germinal epithelium in fishes with protogynous sex reversal supports the homology of Sertoli cells and follicle cells. Spermatogenesis in amphibians develops within spermatocysts in testis lobules. In amniotes vertebrates, the testis is composed of seminiferous tubules wherein spermatogenesis occurs radially. Emerging research indicates that some mammals do not have lifetime determinate fecundity. The fact emerged that germinal epithelia occur in the gonads of all vertebrates examined herein of both sexes and has the same form and function across all vertebrate taxa. Continued study of the form and function of the germinal epithelium in vertebrates

  10. A hot Jupiter orbiting a 2-million-year-old solar-mass T Tauri star.

    PubMed

    Donati, J F; Moutou, C; Malo, L; Baruteau, C; Yu, L; Hébrard, E; Hussain, G; Alencar, S; Ménard, F; Bouvier, J; Petit, P; Takami, M; Doyon, R; Collier Cameron, A

    2016-06-30

    Hot Jupiters are giant Jupiter-like exoplanets that orbit their host stars 100 times more closely than Jupiter orbits the Sun. These planets presumably form in the outer part of the primordial disk from which both the central star and surrounding planets are born, then migrate inwards and yet avoid falling into their host star. It is, however, unclear whether this occurs early in the lives of hot Jupiters, when they are still embedded within protoplanetary disks, or later, once multiple planets are formed and interact. Although numerous hot Jupiters have been detected around mature Sun-like stars, their existence has not yet been firmly demonstrated for young stars, whose magnetic activity is so intense that it overshadows the radial velocity signal that close-in giant planets can induce. Here we report that the radial velocities of the young star V830 Tau exhibit a sine wave of period 4.93 days and semi-amplitude 75 metres per second, detected with a false-alarm probability of less than 0.03 per cent, after filtering out the magnetic activity plaguing the spectra. We find that this signal is unrelated to the 2.741-day rotation period of V830 Tau and we attribute it to the presence of a planet of mass 0.77 times that of Jupiter, orbiting at a distance of 0.057 astronomical units from the host star. Our result demonstrates that hot Jupiters can migrate inwards in less than two million years, probably as a result of planet–disk interactions.

  11. The evolutionary and genetic origins of consciousness in the Cambrian Period over 500 million years ago

    PubMed Central

    Feinberg, Todd E.; Mallatt, Jon

    2013-01-01

    Vertebrates evolved in the Cambrian Period before 520 million years ago, but we do not know when or how consciousness arose in the history of the vertebrate brain. Here we propose multiple levels of isomorphic or somatotopic neural representations as an objective marker for sensory consciousness. All extant vertebrates have these, so we deduce that consciousness extends back to the group's origin. The first conscious sense may have been vision. Then vision, coupled with additional sensory systems derived from ectodermal placodes and neural crest, transformed primitive reflexive systems into image forming brains that map and perceive the external world and the body's interior. We posit that the minimum requirement for sensory consciousness and qualia is a brain including a forebrain (but not necessarily a developed cerebral cortex/pallium), midbrain, and hindbrain. This brain must also have (1) hierarchical systems of intercommunicating, isomorphically organized, processing nuclei that extensively integrate the different senses into representations that emerge in upper levels of the neural hierarchy; and (2) a widespread reticular formation that integrates the sensory inputs and contributes to attention, awareness, and neural synchronization. We propose a two-step evolutionary history, in which the optic tectum was the original center of multi-sensory conscious perception (as in fish and amphibians: step 1), followed by a gradual shift of this center to the dorsal pallium or its cerebral cortex (in mammals, reptiles, birds: step 2). We address objections to the hypothesis and call for more studies of fish and amphibians. In our view, the lamprey has all the neural requisites and is likely the simplest extant vertebrate with sensory consciousness and qualia. Genes that pattern the proposed elements of consciousness (isomorphism, neural crest, placodes) have been identified in all vertebrates. Thus, consciousness is in the genes, some of which are already known. PMID

  12. The evolutionary and genetic origins of consciousness in the Cambrian Period over 500 million years ago.

    PubMed

    Feinberg, Todd E; Mallatt, Jon

    2013-01-01

    Vertebrates evolved in the Cambrian Period before 520 million years ago, but we do not know when or how consciousness arose in the history of the vertebrate brain. Here we propose multiple levels of isomorphic or somatotopic neural representations as an objective marker for sensory consciousness. All extant vertebrates have these, so we deduce that consciousness extends back to the group's origin. The first conscious sense may have been vision. Then vision, coupled with additional sensory systems derived from ectodermal placodes and neural crest, transformed primitive reflexive systems into image forming brains that map and perceive the external world and the body's interior. We posit that the minimum requirement for sensory consciousness and qualia is a brain including a forebrain (but not necessarily a developed cerebral cortex/pallium), midbrain, and hindbrain. This brain must also have (1) hierarchical systems of intercommunicating, isomorphically organized, processing nuclei that extensively integrate the different senses into representations that emerge in upper levels of the neural hierarchy; and (2) a widespread reticular formation that integrates the sensory inputs and contributes to attention, awareness, and neural synchronization. We propose a two-step evolutionary history, in which the optic tectum was the original center of multi-sensory conscious perception (as in fish and amphibians: step 1), followed by a gradual shift of this center to the dorsal pallium or its cerebral cortex (in mammals, reptiles, birds: step 2). We address objections to the hypothesis and call for more studies of fish and amphibians. In our view, the lamprey has all the neural requisites and is likely the simplest extant vertebrate with sensory consciousness and qualia. Genes that pattern the proposed elements of consciousness (isomorphism, neural crest, placodes) have been identified in all vertebrates. Thus, consciousness is in the genes, some of which are already known.

  13. A half-million-year record of paleoclimate from the Lake Manix Core, Mojave Desert, California

    USGS Publications Warehouse

    Reheis, Marith C.; Bright, Jordon; Lund, Steve P.; Miller, David M.; Skipp, Gary; Fleck, Robert J.

    2012-01-01

    Pluvial lakes in the southwestern U.S. responded sensitively to past climate through effects on rainfall, runoff, and evaporation. Although most studies agree that pluvial lakes in the southwestern U.S. reached their highest levels coeval with glacial stages, the specific timing of increased effective moisture and lake-level rise is debated, particularly for the southwesternmost lakes. We obtained a 45-m core of lacustrine sediment from Lake Manix, the former terminus of the Mojave River prior to about 25 ka, and supplemented data from the core with outcrop studies. These sediments provide a robust record of Mojave River discharge over the last half-million years. Lake Manix persisted from OIS 12 through early OIS 2, including during interstadial OIS 3 and interglacials OIS 5, 7, and 9. The ostracode faunal record displays a shift from an unexpectedly warm, summer-dominated lake hydrology during OIS 12 to predominantly colder, winter-dominated conditions afterwards. The ostracode-based stable isotope record displays a large degree of intra-sample variability and does not mimic other well-known isotopic records of climate change. Evaporation likely buffered the Manix δ18O record from most of the expected isotopic differences between interglacial and glacial-interval discharge. Isotopically depleted and stable lakes occurred only four to six times, most notably during OIS 7 and OIS 9. Internal drainage-basin changes also affected the isotopic record. Persistence of lakes in the Manix basin during interglacials requires atmospheric or oceanic circulation controls on the mean position of the Pacific storm track other than large ice sheets. We propose that the relative strength and sign of the Northern Annular Mode (NAM) and its influence on atmospheric river-derived precipitation is a potential explanation.

  14. A hot Jupiter orbiting a 2-million-year-old solar-mass T Tauri star

    NASA Astrophysics Data System (ADS)

    Donati, J. F.; Moutou, C.; Malo, L.; Baruteau, C.; Yu, L.; Hébrard, E.; Hussain, G.; Alencar, S.; Ménard, F.; Bouvier, J.; Petit, P.; Takami, M.; Doyon, R.; Cameron, A. Collier

    2016-06-01

    Hot Jupiters are giant Jupiter-like exoplanets that orbit their host stars 100 times more closely than Jupiter orbits the Sun. These planets presumably form in the outer part of the primordial disk from which both the central star and surrounding planets are born, then migrate inwards and yet avoid falling into their host star. It is, however, unclear whether this occurs early in the lives of hot Jupiters, when they are still embedded within protoplanetary disks, or later, once multiple planets are formed and interact. Although numerous hot Jupiters have been detected around mature Sun-like stars, their existence has not yet been firmly demonstrated for young stars, whose magnetic activity is so intense that it overshadows the radial velocity signal that close-in giant planets can induce. Here we report that the radial velocities of the young star V830 Tau exhibit a sine wave of period 4.93 days and semi-amplitude 75 metres per second, detected with a false-alarm probability of less than 0.03 per cent, after filtering out the magnetic activity plaguing the spectra. We find that this signal is unrelated to the 2.741-day rotation period of V830 Tau and we attribute it to the presence of a planet of mass 0.77 times that of Jupiter, orbiting at a distance of 0.057 astronomical units from the host star. Our result demonstrates that hot Jupiters can migrate inwards in less than two million years, probably as a result of planet-disk interactions.

  15. Marine and terrestrial herbivores display convergent chemical ecology despite 400 million years of independent evolution

    PubMed Central

    Rasher, Douglas B.; Stout, E. Paige; Engel, Sebastian; Shearer, Tonya L.; Kubanek, Julia; Hay, Mark E.

    2015-01-01

    Chemical cues regulate key ecological interactions in marine and terrestrial ecosystems. They are particularly important in terrestrial plant–herbivore interactions, where they mediate both herbivore foraging and plant defense. Although well described for terrestrial interactions, the identity and ecological importance of herbivore foraging cues in marine ecosystems remain unknown. Here we show that the specialist gastropod Elysia tuca hunts its seaweed prey, Halimeda incrassata, by tracking 4-hydroxybenzoic acid to find vegetative prey and the defensive metabolite halimedatetraacetate to find reproductive prey. Foraging cues were predicted to be polar compounds but instead were nonpolar secondary metabolites similar to those used by specialist terrestrial insects. Tracking halimedatetraacetate enables Elysia to increase in abundance by 12- to 18-fold on reproductive Halimeda, despite reproduction in Halimeda being rare and lasting for only ∼36 h. Elysia swarm to reproductive Halimeda where they consume the alga’s gametes, which are resource rich but are chemically defended from most consumers. Elysia sequester functional chloroplasts and halimedatetraacetate from Halimeda to become photosynthetic and chemically defended. Feeding by Elysia suppresses the growth of vegetative Halimeda by ∼50%. Halimeda responds by dropping branches occupied by Elysia, apparently to prevent fungal infection associated with Elysia feeding. Elysia is remarkably similar to some terrestrial insects, not only in its hunting strategy, but also its feeding method, defense tactics, and effects on prey behavior and performance. Such striking parallels indicate that specialist herbivores in marine and terrestrial systems can evolve convergent ecological strategies despite 400 million years of independent evolution in vastly different habitats. PMID:26324909

  16. Changes in southern hemispheric polar amplification over the past 5 million years revealed by climate modelling

    NASA Astrophysics Data System (ADS)

    Hoencamp, Jori; Stap, Lennert; Tuenter, Erik; Lourens, Luc; van de Wal, Roderik

    2016-04-01

    Knowledge on polar amplification is important to relate high latitude climate records to global mean temperature changes. Several studies have pointed out that the strength of polar amplification in the Northern Hemisphere varies considerably due to the presence of large ice sheets and more sea ice during colder climate conditions. As a result, the polar amplification in the Northern Hemisphere decreases for warmer climates. In this study, we address the fact that these changes in the Northern Hemisphere also affect the polar amplification in the Southern Hemisphere. We study the Southern and Northern Hemisphere amplification together over the past 5 million years with the CLIMBER-2 intermediate complexity model. Radiation, land ice extent and height, and greenhouse gases are prescribed as forcing. We find that in contrast to the reduction in polar amplification in the Northern Hemisphere, polar amplification in the Southern Hemisphere increases for warmer climates. The amplification decreases in the Northern Hemisphere from 2.7 during glacial conditions to 1.6 for a pre-industrial climate, which is line with other climate simulations. Over the same CO2 range the southern hemispheric polar amplification increases from 1 to 1.6. This is caused by the fact that the atmospheric transport needed to balance the radiation surplus in the equatorial region needs to be compensated by relatively stronger transport of energy in Southern direction while the transport in Northern direction reduces. This reduction in Northern direction is driven by less (land and sea) ice resulting in a smaller meridional gradient in Northern direction and hence a smaller atmospheric transport. As a consequence, the traditional scaled (with LGM temperature) Dome C record needs to be corrected with a maximum of 0.6 degrees half-way glacial and interglacial conditions, if it is to be interpreted as global mean temperature change indicator. While this changes the amplitude, the phasing of

  17. Investigating changes in North Pacific intermediate water during the last 4 million years

    NASA Astrophysics Data System (ADS)

    Ramirez, B.; Ford, H. L.; Ross, C.

    2015-12-01

    In the ocean, intermediate and deep water circulation is extremely important because it transports heat and nutrients globally. The Pliocene warm period is an optimal time in Earth's history to study how intermediate and deep water circulation functions during globally warm periods. Here we use an Ocean Drilling Program (ODP) marine sediment core from the California Margin to investigate changes in intermediate water during the last 4 million years. The benthic foraminifera Uvigerina spp. were picked from ODP Site 1014A core samples, then crushed and chemically cleaned. Using the Inductively Coupled Plasma-Mass Spectrometer (ICP-MS), Mg/Ca and Li/Mg ratios were measured and converted to bottom water temperatures. These temperatures and the previously published δ18O of benthic foraminifera (Kwiek and Ravelo, 1999) were used to calculate the δ18O of seawater. Reconstructed temperatures during the Plio-Pleistocene are ~2°C, which is cooler than modern temperature (~4°C). As the California Margin is a highly productive region, the Plio-Pleistocene cooler than modern temperatures could be due to post-depositional processes within the sediment as we would expect warmer temperatures during the warm Pliocene in comparison to modern; for this reason, we interpret relative change in temperature and δ18O of seawater changes over the Plio-Pleistocene. Results show that intermediate water during the Pliocene was warmer than Pleistocene. Mg/Ca and Li/Mg-derived δ18O of seawater records increase at ~3100 kyrs, suggesting an increase in ice volume consistent with initiation of Northern Hemisphere Glaciation. To isolate local changes in δ18O of seawater, we used available deep Pacific δ18O of seawater records to approximate for changes in mean δ18O of seawater related to Northern Hemisphere Glaciation. Local δ18O of seawater show that intermediate water during the Pliocene was fresher than in the Pleistocene.

  18. Skull and brain of a 300-million-year-old chimaeroid fish revealed by synchrotron holotomography

    PubMed Central

    Pradel, Alan; Langer, Max; Maisey, John G.; Geffard-Kuriyama, Didier; Cloetens, Peter; Janvier, Philippe; Tafforeau, Paul

    2009-01-01

    Living cartilaginous fishes, or chondrichthyans, include numerous elasmobranch (sharks and rays) species but only few chimaeroid (ratfish) species. The early history of chimaeroids, or holocephalans, and the modalities of their divergence from elasmobranchs are much debated. During Carboniferous times, 358–300 million years (Myr) ago, they underwent a remarkable evolutionary radiation, with some odd and poorly understood forms, including the enigmatic iniopterygians that were known until now from poorly informative flattened impressions. Here, we report iniopterygian skulls found preserved in 3 dimensions in ≈300-Myr-old concretions from Oklahoma and Kansas. The study was performed by using conventional X-ray microtomography (μCT), as well as absorption-based synchrotron microtomography (SR-μCT) [Tafforeau P, et al. (2006) Applications of X-ray synchrotron microtomography for non-destructive 3D studies of paleontological specimens. Appl Phys A 83:95–202] and a new holotomographic approach [Guigay P, Langer M, Boistel R, Cloetens P (2007) Mixed transfer function and transport of intensity approach for phase retrieval in the Fresnel region. Opt Lett 32:1617–1619], which revealed their peculiar anatomy. Iniopterygians also share unique characters with living chimaeroids, suggesting that the key chimaeroid skull features were already established 300 Myr ago. Moreover, SR-μCT of an articulated skull revealed a strikingly brain-shaped structure inside the endocranial cavity, which seems to be an exceptional case of soft-tissue mineralization of the brain, presumably as a result of microbially induced postmortem phosphatization. This was imaged with exceptional accuracy by using holotomography, which demonstrates its great potential to image preserved soft parts in dense fossils. PMID:19273859

  19. PROTOSTELLAR DISK EVOLUTION OVER MILLION-YEAR TIMESCALES WITH A PRESCRIPTION FOR MAGNETIZED TURBULENCE

    SciTech Connect

    Landry, Russell; Dodson-Robinson, Sarah E.; Turner, Neal J.

    2013-07-10

    Magnetorotational instability (MRI) is the most promising mechanism behind accretion in low-mass protostellar disks. Here we present the first analysis of the global structure and evolution of non-ideal MRI-driven T-Tauri disks on million-year timescales. We accomplish this in a 1+1D simulation by calculating magnetic diffusivities and utilizing turbulence activity criteria to determine thermal structure and accretion rate without resorting to a three-dimensional magnetohydrodynamical (MHD) simulation. Our major findings are as follows. First, even for modest surface densities of just a few times the minimum-mass solar nebula, the dead zone encompasses the giant planet-forming region, preserving any compositional gradients. Second, the surface density of the active layer is nearly constant in time at roughly 10 g cm{sup -2}, which we use to derive a simple prescription for viscous heating in MRI-active disks for those who wish to avoid detailed MHD computations. Furthermore, unlike a standard disk with constant-{alpha} viscosity, the disk midplane does not cool off over time, though the surface cools as the star evolves along the Hayashi track. Instead, the MRI may pile material in the dead zone, causing it to heat up over time. The ice line is firmly in the terrestrial planet-forming region throughout disk evolution and can move either inward or outward with time, depending on whether pileups form near the star. Finally, steady-state mass transport is an extremely poor description of flow through an MRI-active disk, as we see both the turnaround in the accretion flow required by conservation of angular momentum and peaks in M-dot (R) bracketing each side of the dead zone. We caution that MRI activity is sensitive to many parameters, including stellar X-ray flux, grain size, gas/small grain mass ratio and magnetic field strength, and we have not performed an exhaustive parameter study here. Our 1+1D model also does not include azimuthal information, which prevents

  20. A quarter-million years of paleoenvironmental change at Bear Lake, Utah and Idaho

    USGS Publications Warehouse

    Kaufman, D.S.; Bright, Jordon; Dean, W.E.; Rosenbaum, J.G.; Moser, K.; Anderson, R. Scott; Colman, Steven M.; Heil, C.W.; Jiménez-Moreno, Gonzalo; Reheis, M.C.; Simmons, K.R.

    2009-01-01

    A continuous, 120-m-long core (BL00-1) from Bear Lake, Utah and Idaho, contains evidence of hydrologic and environmental change over the last two glacial-interglacial cycles. The core was taken at 41.95??N, 111.31??W, near the depocenter of the 60-m-deep, spring-fed, alkaline lake, where carbonate-bearing sediment has accumulated continuously. Chronological control is poor but indicates an average sedimentation rate of 0.54 mm yr-1. Analyses have been completed at multi-centennial to millennial scales, including (in order of decreasing temporal resolution) sediment magnetic properties, oxygen and carbon isotopes on bulk-sediment carbonate, organic- and inorganiccarbon contents, palynology; mineralogy (X-ray diffraction), strontium isotopes on bulk carbonate, ostracode taxonomy, oxygen and carbon isotopes on ostracodes, and diatom assemblages. Massive silty clay and marl constitute most of the core, with variable carbonate content (average = 31 ?? 19%) and oxygen-isotopic values (??18O ranging from -18??? to -5??? in bulk carbonate). These variations, as well as fluctuations of biological indicators, reflect changes in the water and sediment discharged from the glaciated headwaters of the dominant tributary, Bear River, and the processes that influenced sediment delivery to the core site, including lake-level changes. Although its influence has varied, Bear River has remained a tributary to Bear Lake during most of the last quarter-million years. The lake disconnected from the river and, except for a few brief excursions, retracted into a topographically closed basin during global interglaciations (during parts of marine isotope stages 7, 5, and 1). These intervals contain up to 80% endogenic aragonite with high ??18O values (average = -5.8 ?? 1.7???), indicative of strongly evaporitic conditions. Interglacial intervals also are dominated by small, benthic/tychoplanktic fragilarioid species indicative of reduced habitat availability associated with low lake levels

  1. A Progressively Wetter Climate in Southern East Africa Over the Past 1.3 Million Years

    NASA Astrophysics Data System (ADS)

    Berke, M. A.; Johnson, T. C.; Werne, J. P.; Contreras, S.; Brown, E. T.

    2015-12-01

    We present a 1.3 million year record of hydroclimate in the basin of Lake Malawi, the second deepest lake in Africa, located at ~10 - 15ºS latitude in the East African Rift Valley. The lake is ~550 km long, has a maximum depth of 706 m, and is presently anoxic below ~200 m. While the lake is an open basin today with outflow through the Shire River at its southern end, the surface of Lake Malawi has dropped well below the elevation of its outlet on several occasions in its past. We examined a 380 m sediment sequence taken from a water depth of 590 m, from Cores MAL05-1B and MAL05-1C of the Lake Malawi Drilling Project. Sediment samples were analyzed for the carbon isotopic composition of the C29 - C33 n-alkanes derived from fossil leaf waxes, which primarily reflect the relative abundance of C3 (mostly trees and shrubs) and C4 (mostly grass) vegetation, i.e., relatively humid or arid conditions, respectively, in the lake basin. The δ13Cwax record portrays a transition from a highly variable and predominantly arid climate prior to 900 ka to a progressively more humid environment after the Mid-Pleistocene Transition, dominated by 100 ky cycles consisting of warm, wet interglacial periods alternating with relatively cool, dry glacial periods. This shift towards more humid conditions in the Lake Malawi basin contrasts with the well-documented progression towards a more arid environment in North Africa over the same period, as reflected in the carbon isotopic record of soil carbonates and in dust records from marine sediment recovered from the Atlantic Ocean and Gulf of Aden. Aridification in the Horn of Africa has been attributed to a cooling of the Indian Ocean. Model results suggest that this would be accompanied by a weakening of a localized Walker circulation over the Indian Ocean, less ascending air over the western Indian Ocean and coastal Africa, and more precipitation in the Rift Valley.

  2. On the state dependency of the equilibrium climate sensitivity during the last 5 million years

    NASA Astrophysics Data System (ADS)

    Köhler, P.; de Boer, B.; von der Heydt, A. S.; Stap, L. B.; van de Wal, R. S. W.

    2015-12-01

    It is still an open question how equilibrium warming in response to increasing radiative forcing - the specific equilibrium climate sensitivity S - depends on background climate. We here present palaeodata-based evidence on the state dependency of S, by using CO2 proxy data together with a 3-D ice-sheet-model-based reconstruction of land ice albedo over the last 5 million years (Myr). We find that the land ice albedo forcing depends non-linearly on the background climate, while any non-linearity of CO2 radiative forcing depends on the CO2 data set used. This non-linearity has not, so far, been accounted for in similar approaches due to previously more simplistic approximations, in which land ice albedo radiative forcing was a linear function of sea level change. The latitudinal dependency of ice-sheet area changes is important for the non-linearity between land ice albedo and sea level. In our set-up, in which the radiative forcing of CO2 and of the land ice albedo (LI) is combined, we find a state dependence in the calculated specific equilibrium climate sensitivity, S[CO2,LI], for most of the Pleistocene (last 2.1 Myr). During Pleistocene intermediate glaciated climates and interglacial periods, S[CO2,LI] is on average ~ 45 % larger than during Pleistocene full glacial conditions. In the Pliocene part of our analysis (2.6-5 Myr BP) the CO2 data uncertainties prevent a well-supported calculation for S[CO2,LI], but our analysis suggests that during times without a large land ice area in the Northern Hemisphere (e.g. before 2.82 Myr BP), the specific equilibrium climate sensitivity, S[CO2,LI], was smaller than during interglacials of the Pleistocene. We thus find support for a previously proposed state change in the climate system with the widespread appearance of northern hemispheric ice sheets. This study points for the first time to a so far overlooked non-linearity in the land ice albedo radiative forcing, which is important for similar palaeodata

  3. On the state-dependency of the equilibrium climate sensitivity during the last 5 million years

    NASA Astrophysics Data System (ADS)

    Köhler, P.; de Boer, B.; von der Heydt, A. S.; Stap, L. B.; van de Wal, R. S. W.

    2015-07-01

    A still open question is how equilibrium warming in response to increasing radiative forcing - the specific equilibrium climate sensitivity S - is depending on background climate. We here present paleo-data based evidence on the state-dependency of S, by using CO2 proxy data together with 3-D ice-sheet model-based reconstruction of land ice albedo over the last 5 million years (Myr). We find that the land-ice albedo forcing depends non-linearly on the background climate, while any non-linearity of CO2 radiative forcing depends on the CO2 data set used. This non-linearity was in similar approaches not accounted for due to previously more simplistic approximations of land-ice albedo radiative forcing being a linear function of sea level change. Important for the non-linearity between land-ice albedo and sea level is a latitudinal dependency in ice sheet area changes.In our setup, in which the radiative forcing of CO2 and of the land-ice albedo (LI) is combined, we find a state-dependency in the calculated specific equilibrium climate sensitivity S[CO2,LI] for most of the Pleistocene (last 2.1 Myr). During Pleistocene intermediate glaciated climates and interglacial periods S[CO2,LI] is on average ∼ 45 % larger than during Pleistocene full glacial conditions. In the Pliocene part of our analysis (2.6-5 Myr BP) the CO2 data uncertainties prevents a well-supported calculation for S[CO2,LI], but our analysis suggests that during times without a large land-ice area in the Northern Hemisphere (e.g. before 2.82 Myr BP) the specific equilibrium climate sensitivity S[CO2,LI] was smaller than during interglacials of the Pleistocene. We thus find support for a previously proposed state-change in the climate system with the wide appearance of northern hemispheric ice sheets. This study points for the first time to a so far overlooked non-linearity in the land-ice albedo radiative forcing, which is important for similar paleo data-based approaches to calculate climate

  4. Fractures, not Plumes, Have Controlled Major Seamount Volcanism in the Pacific over 170 Million Years

    NASA Astrophysics Data System (ADS)

    Natland, J. H.; Winterer, E. L.

    2003-12-01

    shift laterally in response to whatever was occurring along its eastern spreading boundaries. A very consistent and strong stress regime therefore developed across the Pacific plate with a NNE direction of least principal stress. The change in stress orientation may have taken up to 10 million years, during an interval marked by little or no volcanic productivity at the western end of the Hawaiian chain. Since that time, the predominant alignment of both linear island chains and Puka Puka-type ridges, from the Kodiak-Bowie chain in the Gulf of Alaska to the Louisville Ridge south of the Antarctic convergence, has been orthogonal to this direction. Development of large-volume persistent chains and shorter small-volume chains indicates patterns of differential stress in the plate, variable fertility and geochemistry of the asthenosphere and/or shallow convective overturn of the asthenosphere rather than the action of mantle plumes of different sizes and depths of origin. Tapping of enriched mantle by widespread volcano clusters during the Mesozoic suggests the presence of a shallow asthenospheric source layer rather than multiple narrow conduits. (1) Hieronymus, C.F., and Bercovici, D. 2000. Earth Planet. Sci. Lett. 181, 539-554. (2) Davis, A.S., Gray, L.B., Clague, D.A., and Hein, J.R., 2002 Geochem. Geophys. Geosyst. 3: 10.1029/2001GC0000190, 1-28.

  5. The World of Coelophysis - A New York Dinosaur of 200 Million Years Ago. Geological Survey: Circular 49.

    ERIC Educational Resources Information Center

    Fisher, Donald W.

    Coelophysis was an ostrich-like, meat-eating dinosaur that inhabitated southwestern New York State approximately 200 million years ago. At that time the region was semi-tropical and hosted a bizarre array of amphibians, reptiles, and plants while experiencing unrest in the form of basin settling, earthquakes, faults, and intrusions and outpourings…

  6. Fossil microorganisms from the approximately 2800 to 2500 million-year-old Bulawayan stromatolite: Application of ultramicrochemical analyses

    PubMed Central

    Nagy, Lois Anne; Zumberge, John E.

    1976-01-01

    Microfossils, probably representing members of Precambrian photosynthetic communities of bacteria and blue-green algae, have been found in the approximately 2800-2500 million-year-old Bulawayan stromatolites from Rhodesia. Several populations of coccoid and elongate microfossils have been observed in the dark, carbon-rich stromatolite laminae. Some of these elongate forms are morphologically similar to modern bacterial spores. These microfossils were studied in petrographic thin sections and identified by combined scanning electron microscopy-electron microprobe and by analyses of energy dispersive spectra of individual microfossils. The microfossils contain 1-20% organic carbon; some morphotypes contain traces of sulfur and one other, traces of phosphorus. The polymeric nature of the organic carbon was established by analyzing aggregates of microfossils at elevated temperatures in the solid inlet system of an organic mass spectrometer. The coccoid microfossils range in size from 1.2 to 4.3 μm, the elongate microfossils are from 2.4 to 9.8 μm. They are mineralized with dolomite, embedded in a calcite matrix, and are shown to be both indigenous and syngenous with the rock. Identical microfossils also containing organic carbon but mineralized with quartz have been observed in the stromatolites from Belingwe which are part of the Bulawayan Group from Rhodesia. Caution must be used in the interpretation of what these forms are because of their great age and relatively simple morphologies. However, based on morphology and chemical analyses, they represent fossilized bacteria, blue-green algae, or, most likely, both. Images PMID:16592348

  7. Earth-like aqueous debris-flow activity on Mars at high orbital obliquity in the last million years

    PubMed Central

    de Haas, T.; Hauber, E.; Conway, S. J.; van Steijn, H.; Johnsson, A.; Kleinhans, M. G.

    2015-01-01

    Liquid water is currently extremely rare on Mars, but was more abundant during periods of high obliquity in the last few millions of years. This is testified by the widespread occurrence of mid-latitude gullies: small catchment-fan systems. However, there are no direct estimates of the amount and frequency of liquid water generation during these periods. Here we determine debris-flow size, frequency and associated water volumes in Istok crater, and show that debris flows occurred at Earth-like frequencies during high-obliquity periods in the last million years on Mars. Results further imply that local accumulations of snow/ice within gullies were much more voluminous than currently predicted; melting must have yielded centimetres of liquid water in catchments; and recent aqueous activity in some mid-latitude craters was much more frequent than previously anticipated. PMID:26102485

  8. Earth-like aqueous debris-flow activity on Mars at high orbital obliquity in the last million years.

    PubMed

    de Haas, T; Hauber, E; Conway, S J; van Steijn, H; Johnsson, A; Kleinhans, M G

    2015-06-23

    Liquid water is currently extremely rare on Mars, but was more abundant during periods of high obliquity in the last few millions of years. This is testified by the widespread occurrence of mid-latitude gullies: small catchment-fan systems. However, there are no direct estimates of the amount and frequency of liquid water generation during these periods. Here we determine debris-flow size, frequency and associated water volumes in Istok crater, and show that debris flows occurred at Earth-like frequencies during high-obliquity periods in the last million years on Mars. Results further imply that local accumulations of snow/ice within gullies were much more voluminous than currently predicted; melting must have yielded centimetres of liquid water in catchments; and recent aqueous activity in some mid-latitude craters was much more frequent than previously anticipated.

  9. Experimental evidence that an asteroid impact led to the extinction of many species 65 million years ago

    SciTech Connect

    Alvarez, L.W.

    1983-01-01

    An overview is presented of the theory that an asteroid hit the earth 65 million years ago wiping out large numbers of land and marine species. This theory predicts that the clay layer found at the boundary of the Cretaceous and Tertiary Periods would be substantially different chemically from the clays in the limestone above and below the boundary layer. It also predicts the iridium enhancement seen in this boundary layer would be found worldwide. Both predictions have been found to be true. A third prediction was made but not fulfilled: that the five major extinctions which occurred in the last 570 million years were caused by an asteroid impact. The transport mechanism of the dust created by the impact and four mechanisms for the extinction of species are discussed. Criticisms of the theory are also discussed.

  10. Science from Kepler Collateral Data: 50 Kilosecond per Year from 13 Million Stars

    NASA Technical Reports Server (NTRS)

    Kolodziejczak, J. J.; Caldwell, D. A.

    2012-01-01

    As each Kepler frame is read out, light from each star in a CCD column accumulates in successive pixels as they wait for the next row to be read out. This accumulation is the same in the masked rows at the start of the readout and virtual rows at the end of the readout as it is in the science data. A range of these "smear" rows are added together for each long cadence and sent to the ground for calibration purposes. We will introduce and describe this smear collateral data, discuss and demonstrate its potential use for scientific studies exclusive of Kepler calibration,[1,2] including global characteristics of stellar variability, which are influenced by parameters of galactic evolution.

  11. Eastern Indian 3800-million-year-old crust and early mantle differentiation

    USGS Publications Warehouse

    Basu, A.R.; Ray, S.L.; Saha, A.K.; Sarkar, S.N.

    1981-01-01

    Samarium-neodymium data for nine granitic and tonalite gneisses occurring as remnants within the Singhbhum granite batholith in eastern India define an isochron of age 3775 ?? 89 ?? 106 years with an initial 143Nd/144Nd ratio of 0.50798 ?? 0.00007. This age contrasts with the rubidium-strontium age of 3200 ?? 106 years for the same suite of rocks. On the basis of the new samarium-neodynium data, field data, and petrologic data, a scheme of evolution is proposed for the Archean crust in eastern India. The isotopic data provide evidence that parts of the earth's mantle were already differentiated with respect to the chondritic samarium-neodymium ratio 3800 ?? 106 years ago.

  12. A 300-million-year record of atmospheric carbon dioxide from fossil plant cuticles

    NASA Astrophysics Data System (ADS)

    Retallack, Gregory J.

    2001-05-01

    To understand better the link between atmospheric CO2 concentrations and climate over geological time, records of past CO2 are reconstructed from geochemical proxies. Although these records have provided us with a broad picture of CO2 variation throughout the Phanerozoic eon (the past 544Myr), inconsistencies and gaps remain that still need to be resolved. Here I present a continuous 300-Myr record of stomatal abundance from fossil leaves of four genera of plants that are closely related to the present-day Ginkgo tree. Using the known relationship between leaf stomatal abundance and growing season CO2 concentrations, I reconstruct past atmospheric CO2 concentrations. For the past 300Myr, only two intervals of low CO2 (<1,000p.p.m.v.) are inferred, both of which coincide with known ice ages in Neogene (1-8Myr) and early Permian (275-290Myr) times. But for most of the Mesozoic era (65-250Myr), CO2 levels were high (1,000-2,000p.p.m.v.), with transient excursions to even higher CO2 (>2,000p.p.m.v.) concentrations. These results are consistent with some reconstructions of past CO2 (refs 1, 2) and palaeotemperature records, but suggest that CO2 reconstructions based on carbon isotope proxies may be compromised by episodic outbursts of isotopically light methane. These results support the role of water vapour, methane and CO2 in greenhouse climate warming over the past 300Myr.

  13. The genomic impact of 100 million years of social evolution in seven ant species.

    PubMed

    Gadau, Jürgen; Helmkampf, Martin; Nygaard, Sanne; Roux, Julien; Simola, Daniel F; Smith, Chris R; Suen, Garret; Wurm, Yannick; Smith, Christopher D

    2012-01-01

    Ants (Hymenoptera, Formicidae) represent one of the most successful eusocial taxa in terms of both their geographic distribution and species number. The publication of seven ant genomes within the past year was a quantum leap for socio- and ant genomics. The diversity of social organization in ants makes them excellent model organisms to study the evolution of social systems. Comparing the ant genomes with those of the honeybee, a lineage that evolved eusociality independently from ants, and solitary insects suggests that there are significant differences in key aspects of genome organization between social and solitary insects, as well as among ant species. Altogether, these seven ant genomes open exciting new research avenues and opportunities for understanding the genetic basis and regulation of social species, and adaptive complex systems in general.

  14. Constraints on solar particle events from comparisons of recent events and million-year averages

    SciTech Connect

    Reedy, R.C.

    1995-12-01

    Several sets of measurements of the fluxes of solar energetic particles (SEPs) above 10 MeV have been used to apply limits to huge solar particle events (SPEs) in the past. Direct measurements of SEPs are used to get event-integrated solar-proton fluences for SPEs since about 1965. Indirect measurements of SEPs in events from 1956 until 1963 have been used with radioactivities measured in lunar rocks to get event-integrated solar-proton fluences for the larger events back to 1956. A cumulative-probability plot of these event-integrated fluences for all energies above 10 MeV shows a fairly smooth trend from fluences of 10{sub 7} protons/cm{sup 2} up to the largest events (3 x 10{sup 10} protons/cm{sup 2}) but there are no events with higher fluences. Activities of radionuclides in the tops of lunar rocks were used to get average fluxes of solar protons for time periods from {approximately} 10{sup 4} to {approximately} 10{sup 7} years, which are similar to those over the last four decades. These proton fluxes from lunar radionuclides indicate that the long-term trend for huge events does not follow the modern trend for event fluences up to {approximately}3 x 10{sup 10} protons/cm{sup 2}, but that huge events (orders of magnitude larger than {approximately}10{sup 11} protons/cm{sup 2}) have been very rare or nonexistent during the last {approximately}10{sup 7} years.

  15. North Pacific seasonality and the glaciation of North America 2.7 million years ago

    NASA Astrophysics Data System (ADS)

    Haug, G. H.; Ganopolski, A.; Sigman, D. M.; Rosell-Mele, A.; Swann, G. E.; Tiedemann, R.; Jaccard, S. L.; Bollmann, J.; Maslin, M. A.; Leng, M. J.; Eglinton, G.

    2006-12-01

    To initiate and sustain the large Northern Hemisphere ice sheets of the Plio-Pleistocene ice ages, in particular the large Laurentide ice masses on North America, two requirements are broadly recognized. First, the more polar continental areas must be sufficiently cold for precipitation to fall as snow rather than rain and for snow and ice to survive the warm summer melting season. Second, adequate moisture must be introduced to high northern latitudes to promote the accumulation of glacial ice. In attempts to explain the initiation of major Northern Hemisphere Glaciation 2.7 Myr ago, much attention has been given to the temperature requirements of continental glaciation. The time interval between 4.5 and 3.1 Myr was dominated by a pronounced long-term minimum in the amplitude of the 41 kyr cycle in the obliquity of Earth's rotation which would have failed to produce particularly cold northern hemisphere summers, the key requirement posited by Milankovitch for the onset of northern hemisphere glaciation. During this time interval, there may have been several aborted shifts toward glaciation, for example between 4.1 - 3.9 Myr and 3.5 - 3.3 Myr. During the late Pliocene and early Pleistocene, a high amplitude in the obliquity cycle resulted in periods of low tilt angle, which, in turn, would have yielded periods with cold summers in the Northern Hemisphere. Thus, it has been suggested that the progressive increase in the amplitude of the obliquity cycle tipped the scale between 3.1 - 2.5 Myr, allowing for long-term expansion of Northern Hemisphere ice. In short, our long-held view of the temperature requirement of glaciation is largely consistent with the timing of the onset of Northern Hemisphere Glaciation. However, the onset of Northern Hemisphere glaciation has proven to be inconsistent with ideas regarding the water vapor requirement. The subarctic Pacific represents a major source of water vapor to boreal North America yet has largely been overlooked in efforts

  16. Specialised emission pattern of leaf trace in a late Permian (253 million-years old) conifer

    PubMed Central

    Wei, Hai-Bo; Feng, Zhuo; Yang, Ji-Yuan; Chen, Yu-Xuan; Shen, Jia-Jia; He, Xiao-Yuan

    2015-01-01

    Leaf traces are important structures in higher plants that connect leaves and the stem vascular system. The anatomy and emission pattern of leaf traces are well studied in extant vascular plants, but remain poorly understood in fossil lineages. We quantitatively analysed the leaf traces in the late Permian conifer Ningxiaites specialis from Northwest China based on serial sections through pith, primary and secondary xylems. A complete leaf traces emission pattern of a conifer is presented for the first time from the late Palaeozoic. Three to five monarch leaf traces are grouped in clusters, arranged in a helical phyllotaxis. The leaf traces in each cluster can be divided into upper, middle and lower portions, and initiate at the pith periphery and cross the wood horizontally. The upper leaf trace increases its diameter during the first growth increment and then diminishes completely, which indicates leaf abscission at the end of the first year. The middle trace immediately bifurcates once or twice to form two or three vascular bundles. The lower trace persists as a single bundle during its entire length. The intricate leaf trace dynamics indicates this fossil plant had a novel evolutionary habit by promoting photosynthetic capability for the matured plant. PMID:26198410

  17. Specialised emission pattern of leaf trace in a late Permian (253 million-years old) conifer.

    PubMed

    Wei, Hai-Bo; Feng, Zhuo; Yang, Ji-Yuan; Chen, Yu-Xuan; Shen, Jia-Jia; He, Xiao-Yuan

    2015-07-22

    Leaf traces are important structures in higher plants that connect leaves and the stem vascular system. The anatomy and emission pattern of leaf traces are well studied in extant vascular plants, but remain poorly understood in fossil lineages. We quantitatively analysed the leaf traces in the late Permian conifer Ningxiaites specialis from Northwest China based on serial sections through pith, primary and secondary xylems. A complete leaf traces emission pattern of a conifer is presented for the first time from the late Palaeozoic. Three to five monarch leaf traces are grouped in clusters, arranged in a helical phyllotaxis. The leaf traces in each cluster can be divided into upper, middle and lower portions, and initiate at the pith periphery and cross the wood horizontally. The upper leaf trace increases its diameter during the first growth increment and then diminishes completely, which indicates leaf abscission at the end of the first year. The middle trace immediately bifurcates once or twice to form two or three vascular bundles. The lower trace persists as a single bundle during its entire length. The intricate leaf trace dynamics indicates this fossil plant had a novel evolutionary habit by promoting photosynthetic capability for the matured plant.

  18. The rise of oxygen over the past 205 million years and the evolution of large placental mammals.

    PubMed

    Falkowski, Paul G; Katz, Miriam E; Milligan, Allen J; Fennel, Katja; Cramer, Benjamin S; Aubry, Marie Pierre; Berner, Robert A; Novacek, Michael J; Zapol, Warren M

    2005-09-30

    On the basis of a carbon isotopic record of both marine carbonates and organic matter from the Triassic-Jurassic boundary to the present, we modeled oxygen concentrations over the past 205 million years. Our analysis indicates that atmospheric oxygen approximately doubled over this period, with relatively rapid increases in the early Jurassic and the Eocene. We suggest that the overall increase in oxygen, mediated by the formation of passive continental margins along the Atlantic Ocean during the opening phase of the current Wilson cycle, was a critical factor in the evolution, radiation, and subsequent increase in average size of placental mammals.

  19. A Neptune-sized transiting planet closely orbiting a 5-10-million-year-old star

    NASA Astrophysics Data System (ADS)

    David, Trevor J.

    2016-10-01

    Theories of the formation and early evolution of planetary systems postulate that planets are born in circumstellar disks, and undergo radial migration during and after dissipation of the dust and gas disk from which they formed. The precise ages of meteorites indicate that planetesimals - the building blocks of planets - are produced within the first million years of a star's life. A prominent question is: how early can one find fully formed planets like those frequently detected on short orbital periods around mature stars? Some theories suggest the in situ formation of planets close to their host stars is unlikely and the existence of such planets is evidence for large scale migration. Other theories posit that planet assembly at small orbital separations may be common. Here we report on a newly-born, transiting planet orbiting its star every 5.4 days. The planet is 50 per cent larger than Neptune, and its mass is less than 3.6 times Jupiter (at 99.7 per cent confidence), with a true mass likely to be within a factor of several of Neptune's. The 5-10 million year old star has a tenuous dust disk extending outwards from about 2 times the Earth-Sun separation, in addition to the large planet located at less than one-twentieth the Earth-Sun separation.

  20. A Neptune-sized transiting planet closely orbiting a 5–10-million-year-old star.

    PubMed

    David, Trevor J; Hillenbrand, Lynne A; Petigura, Erik A; Carpenter, John M; Crossfield, Ian J M; Hinkley, Sasha; Ciardi, David R; Howard, Andrew W; Isaacson, Howard T; Cody, Ann Marie; Schlieder, Joshua E; Beichman, Charles A; Barenfeld, Scott A

    2016-06-30

    Theories of the formation and early evolution of planetary systems postulate that planets are born in circumstellar disks, and undergo radial migration during and after dissipation of the dust and gas disk from which they formed. The precise ages of meteorites indicate that planetesimals—the building blocks of planets—are produced within the first million years of a star’s life. Fully formed planets are frequently detected on short orbital periods around mature stars. Some theories suggest that the in situ formation of planets close to their host stars is unlikely and that the existence of such planets is therefore evidence of large-scale migration. Other theories posit that planet assembly at small orbital separations may be common. Here we report a newly born, transiting planet orbiting its star with a period of 5.4 days. The planet is 50 per cent larger than Neptune, and its mass is less than 3.6 times that of Jupiter (at 99.7 per cent confidence), with a true mass likely to be similar to that of Neptune. The star is 5–10 million years old and has a tenuous dust disk extending outward from about twice the Earth–Sun separation, in addition to the fully formed planet located at less than one-twentieth of the Earth–Sun separation.

  1. A Neptune-sized transiting planet closely orbiting a 5-10-million-year-old star

    NASA Astrophysics Data System (ADS)

    David, Trevor J.; Hillenbrand, Lynne A.; Petigura, Erik A.; Carpenter, John M.; Crossfield, Ian J. M.; Hinkley, Sasha; Ciardi, David R.; Howard, Andrew W.; Isaacson, Howard T.; Cody, Ann Marie; Schlieder, Joshua E.; Beichman, Charles A.; Barenfeld, Scott A.

    2016-06-01

    Theories of the formation and early evolution of planetary systems postulate that planets are born in circumstellar disks, and undergo radial migration during and after dissipation of the dust and gas disk from which they formed. The precise ages of meteorites indicate that planetesimals—the building blocks of planets—are produced within the first million years of a star’s life. Fully formed planets are frequently detected on short orbital periods around mature stars. Some theories suggest that the in situ formation of planets close to their host stars is unlikely and that the existence of such planets is therefore evidence of large-scale migration. Other theories posit that planet assembly at small orbital separations may be common. Here we report a newly born, transiting planet orbiting its star with a period of 5.4 days. The planet is 50 per cent larger than Neptune, and its mass is less than 3.6 times that of Jupiter (at 99.7 per cent confidence), with a true mass likely to be similar to that of Neptune. The star is 5-10 million years old and has a tenuous dust disk extending outward from about twice the Earth-Sun separation, in addition to the fully formed planet located at less than one-twentieth of the Earth-Sun separation.

  2. Deep drilling of ancient Lake Ohrid (Balkan region) to capture over 1 million years of evolution and global climate cycling

    NASA Astrophysics Data System (ADS)

    Wagner, Bernd; Francke, Alexander; Wilke, Thomas; Krastel, Sebastian; Zanchetta, Giovanni; Sulpizio, Roberto; Reicherter, Klaus; Leng, Melanie; Grazhdani, Andon; Trajanovski, Sasho; Levkov, Zlatko; Reed, Jane; Wonik, Thomas

    2014-05-01

    Ancient lakes, with sediment records spanning >1 million years, are very rare. The UNESCO World Heritage site of Lake Ohrid in the Balkan region is thought to be the oldest lake in continuous existence in Europe and, with 212 endemic species described to date, is a hotspot of evolution. An international group of scientists working on a project entitled 'Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO)' realized a deep drilling campaign of Lake Ohrid in spring 2013. Based on several coring seismic campaigns between 2004 and 2011, Lake Ohrid became the target of an ICDP deep drilling campaign, with specific research aims: (i) obtain precise information about the age and origin of the lake, (ii) unravel the lake's seismotectonic history, (iii) obtain a continuous record of Quaternary volcanic activity and climate change, and (iv) investigate the influence of major geological/environmental events on evolution and the generation of extraordinary endemic biodiversity. Drilling began in April 2013 using the Deep Lake Drilling System (DLDS) of DOSECC (USA). The campaign, completed by late May, was deemed one of the most successful ICDP lake drilling projects, with a total of ~2100 m of sediment recovered from four different sites. At the central "DEEP" site, hydro-acoustic data indicated a maximum sediment fill of ca. 700 m, of which the uppermost 568 m was recovered. Coarse gravel and pebbles underlying clay and shallow water facies hampered deeper penetration. A total of 1526 m of sediment cores was collected from six boreholes, with a composite field recovery ('master core') of 544 m (95%). Three additional sites were drilled in order to analyze lake-level fluctuations, catchment dynamics, biodiversity and evolution processes ("Cerava", deepest drilled depth: 90 m), to investigate active tectonics and spring dynamics ("Gradiste", deepest drilled depth: 123 m), and to try to understand the geological origins of the Ohrid Basin ("Pestani

  3. Signatures of a Two Million Year Old Supernova in the Spectra of Cosmic Ray Protons, Antiprotons, and Positrons.

    PubMed

    Kachelrieß, M; Neronov, A; Semikoz, D V

    2015-10-30

    The locally observed cosmic ray spectrum has several puzzling features, such as the excess of positrons and antiprotons above ~20  GeV and the discrepancy in the slopes of the spectra of cosmic ray protons and heavier nuclei in the TeV-PeV energy range. We show that these features are consistently explained by a nearby source which was active approximately two million years ago and has injected (2-3)×10^{50} erg in cosmic rays. The transient nature of the source and its overall energy budget point to the supernova origin of this local cosmic ray source. The age of the supernova suggests that the local cosmic ray injection was produced by the same supernova that has deposited ^{60}Fe isotopes in the deep ocean crust.

  4. When a 520 million-year-old Chengjiang fossil meets a modern micro-CT – a case study

    PubMed Central

    Liu, Yu; Scholtz, Gerhard; Hou, Xianguang

    2015-01-01

    The 520 million-year-old Chengjiang biota of China (UNESCO World Heritage) presents the earliest known evidence of the so-called Cambrian Explosion. Studies, however, have mainly been limited to the information exposed on the surface of the slabs. Thus far, structures preserved inside the slabs were accessed by careful removal of the matrix, in many cases with the unfortunate sacrifice of some “less important” structures, which destroys elements of exceptionally preserved specimens. Here, we show for the first time that microtomography (micro-CT) can reveal structures situated inside a Chengjiang fossil slab without causing any damage. In the present study a trilobitomorph arthropod (Xandarella spectaculum) can be reliably identified only with the application of micro-CT. We propose that this technique is an important tool for studying three-dimensionally preserved Chengjiang fossils and, most likely, also those from other biota with a comparable type of preservation, specifically similar iron concentrations. PMID:26238773

  5. Evidence for the stability of the West Antarctic Ice Sheet divide for 1.4 million years

    NASA Astrophysics Data System (ADS)

    Hein, Andrew S.; Woodward, John; Marrero, Shasta M.; Dunning, Stuart A.; Steig, Eric J.; Freeman, Stewart P. H. T.; Stuart, Finlay M.; Winter, Kate; Westoby, Matthew J.; Sugden, David E.

    2016-02-01

    Past fluctuations of the West Antarctic Ice Sheet (WAIS) are of fundamental interest because of the possibility of WAIS collapse in the future and a consequent rise in global sea level. However, the configuration and stability of the ice sheet during past interglacial periods remains uncertain. Here we present geomorphological evidence and multiple cosmogenic nuclide data from the southern Ellsworth Mountains to suggest that the divide of the WAIS has fluctuated only modestly in location and thickness for at least the last 1.4 million years. Fluctuations during glacial-interglacial cycles appear superimposed on a long-term trajectory of ice-surface lowering relative to the mountains. This implies that as a minimum, a regional ice sheet centred on the Ellsworth-Whitmore uplands may have survived Pleistocene warm periods. If so, it constrains the WAIS contribution to global sea level rise during interglacials to about 3.3 m above present.

  6. A 150-million-year-old crab larva and its implications for the early rise of brachyuran crabs.

    PubMed

    Haug, Joachim T; Martin, Joel W; Haug, Carolin

    2015-03-09

    True crabs (Brachyura) are the most successful group of decapod crustaceans. This success is most likely coupled to their life history, including two specialised larval forms, zoea and megalopa. The group is comparably young, starting to diversify only about 100 million years ago (mya), with a dramatic increase in species richness beginning approximately 50 mya. Early evolution of crabs is still very incompletely known. Here, we report a fossil crab larva, 150 mya, documented with up-to-date imaging techniques. It is only the second find of any fossil crab larva, but the first complete one, the first megalopa, and the oldest one (other fossil ca. 110 mya). Despite its age, the new fossil possesses a very modern morphology, being indistinguishable from many extant crab larvae. Hence, modern morphologies must have been present significantly earlier than formerly anticipated. We briefly discuss the impact of this find on our understanding of early crab evolution.

  7. Evidence for the stability of the West Antarctic Ice Sheet divide for 1.4 million years

    PubMed Central

    Hein, Andrew S.; Woodward, John; Marrero, Shasta M.; Dunning, Stuart A.; Steig, Eric J.; Freeman, Stewart P. H. T.; Stuart, Finlay M.; Winter, Kate; Westoby, Matthew J.; Sugden, David E.

    2016-01-01

    Past fluctuations of the West Antarctic Ice Sheet (WAIS) are of fundamental interest because of the possibility of WAIS collapse in the future and a consequent rise in global sea level. However, the configuration and stability of the ice sheet during past interglacial periods remains uncertain. Here we present geomorphological evidence and multiple cosmogenic nuclide data from the southern Ellsworth Mountains to suggest that the divide of the WAIS has fluctuated only modestly in location and thickness for at least the last 1.4 million years. Fluctuations during glacial–interglacial cycles appear superimposed on a long-term trajectory of ice-surface lowering relative to the mountains. This implies that as a minimum, a regional ice sheet centred on the Ellsworth-Whitmore uplands may have survived Pleistocene warm periods. If so, it constrains the WAIS contribution to global sea level rise during interglacials to about 3.3 m above present. PMID:26838462

  8. When a 520 million-year-old Chengjiang fossil meets a modern micro-CT - a case study

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Scholtz, Gerhard; Hou, Xianguang

    2015-08-01

    The 520 million-year-old Chengjiang biota of China (UNESCO World Heritage) presents the earliest known evidence of the so-called Cambrian Explosion. Studies, however, have mainly been limited to the information exposed on the surface of the slabs. Thus far, structures preserved inside the slabs were accessed by careful removal of the matrix, in many cases with the unfortunate sacrifice of some “less important” structures, which destroys elements of exceptionally preserved specimens. Here, we show for the first time that microtomography (micro-CT) can reveal structures situated inside a Chengjiang fossil slab without causing any damage. In the present study a trilobitomorph arthropod (Xandarella spectaculum) can be reliably identified only with the application of micro-CT. We propose that this technique is an important tool for studying three-dimensionally preserved Chengjiang fossils and, most likely, also those from other biota with a comparable type of preservation, specifically similar iron concentrations.

  9. Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures.

    PubMed

    Nutman, Allen P; Bennett, Vickie C; Friend, Clark R L; Van Kranendonk, Martin J; Chivas, Allan R

    2016-09-22

    Biological activity is a major factor in Earth's chemical cycles, including facilitating CO2 sequestration and providing climate feedbacks. Thus a key question in Earth's evolution is when did life arise and impact hydrosphere-atmosphere-lithosphere chemical cycles? Until now, evidence for the oldest life on Earth focused on debated stable isotopic signatures of 3,800-3,700 million year (Myr)-old metamorphosed sedimentary rocks and minerals from the Isua supracrustal belt (ISB), southwest Greenland. Here we report evidence for ancient life from a newly exposed outcrop of 3,700-Myr-old metacarbonate rocks in the ISB that contain 1-4-cm-high stromatolites-macroscopically layered structures produced by microbial communities. The ISB stromatolites grew in a shallow marine environment, as indicated by seawater-like rare-earth element plus yttrium trace element signatures of the metacarbonates, and by interlayered detrital sedimentary rocks with cross-lamination and storm-wave generated breccias. The ISB stromatolites predate by 220 Myr the previous most convincing and generally accepted multidisciplinary evidence for oldest life remains in the 3,480-Myr-old Dresser Formation of the Pilbara Craton, Australia. The presence of the ISB stromatolites demonstrates the establishment of shallow marine carbonate production with biotic CO2 sequestration by 3,700 million years ago (Ma), near the start of Earth's sedimentary record. A sophistication of life by 3,700 Ma is in accord with genetic molecular clock studies placing life's origin in the Hadean eon (>4,000 Ma).

  10. Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures

    NASA Astrophysics Data System (ADS)

    Nutman, Allen P.; Bennett, Vickie C.; Friend, Clark R. L.; van Kranendonk, Martin J.; Chivas, Allan R.

    2016-09-01

    Biological activity is a major factor in Earth’s chemical cycles, including facilitating CO2 sequestration and providing climate feedbacks. Thus a key question in Earth’s evolution is when did life arise and impact hydrosphere-atmosphere-lithosphere chemical cycles? Until now, evidence for the oldest life on Earth focused on debated stable isotopic signatures of 3,800-3,700 million year (Myr)-old metamorphosed sedimentary rocks and minerals from the Isua supracrustal belt (ISB), southwest Greenland. Here we report evidence for ancient life from a newly exposed outcrop of 3,700-Myr-old metacarbonate rocks in the ISB that contain 1-4-cm-high stromatolites—macroscopically layered structures produced by microbial communities. The ISB stromatolites grew in a shallow marine environment, as indicated by seawater-like rare-earth element plus yttrium trace element signatures of the metacarbonates, and by interlayered detrital sedimentary rocks with cross-lamination and storm-wave generated breccias. The ISB stromatolites predate by 220 Myr the previous most convincing and generally accepted multidisciplinary evidence for oldest life remains in the 3,480-Myr-old Dresser Formation of the Pilbara Craton, Australia. The presence of the ISB stromatolites demonstrates the establishment of shallow marine carbonate production with biotic CO2 sequestration by 3,700 million years ago (Ma), near the start of Earth’s sedimentary record. A sophistication of life by 3,700 Ma is in accord with genetic molecular clock studies placing life’s origin in the Hadean eon (>4,000 Ma).

  11. CO2 over the past 5 million years: Continuous simulation and new δ11B-based proxy data

    NASA Astrophysics Data System (ADS)

    Stap, Lennert B.; de Boer, Bas; Ziegler, Martin; Bintanja, Richard; Lourens, Lucas J.; van de Wal, Roderik S. W.

    2016-04-01

    During the past five million yrs, benthic δ18O records indicate a large range of climates, from warmer than today during the Pliocene Warm Period to considerably colder during glacials. Antarctic ice cores have revealed Pleistocene glacial-interglacial CO2 variability of 60-100 ppm, while sea level fluctuations of typically 125 m are documented by proxy data. However, in the pre-ice core period, CO2 and sea level proxy data are scarce and there is disagreement between different proxies and different records of the same proxy. This hampers comprehensive understanding of the long-term relations between CO2, sea level and climate. Here, we drive a coupled climate-ice sheet model over the past five million years, inversely forced by a stacked benthic δ18O record. We obtain continuous simulations of benthic δ18O, sea level and CO2 that are mutually consistent. Our model shows CO2 concentrations of 300 to 470 ppm during the Early Pliocene. Furthermore, we simulate strong CO2 variability during the Pliocene and Early Pleistocene. These features are broadly supported by existing and new δ11B-based proxy CO2 data, but less by alkenone-based records. The simulated concentrations and variations therein are larger than expected from global mean temperature changes. Our findings thus suggest a smaller Earth System Sensitivity than previously thought. This is explained by a more restricted role of land ice variability in the Pliocene. The largest uncertainty in our simulation arises from the mass balance formulation of East Antarctica, which governs the variability in sea level, but only modestly affects the modeled CO2 concentrations.

  12. Developmental Norms of Children Aged 2 1/2-5 Years: A Pilot Study.

    ERIC Educational Resources Information Center

    Muralidharan, Rajalakshmi

    1969-01-01

    The purpose of this pilot study, aside from collection of developmental data on 38 nursery school children aged 2 1/2 to 5 years, was (1) to develop, modify and adapt the testing equipment used in Gesell's Developmental Schedule, in the field of motor, adaptive, language, and personal-social development; (2) to develop elaborate, exhaustive,…

  13. Common Aetiology for Diverse Language Skills in 4 1/2-Year-Old Twins

    ERIC Educational Resources Information Center

    Hayiou-Thomas, Marianna E.; Kovas, Yulia; Harlaar, Nicole; Plomin, Robert; Bishop, Dorothy V. M.; Dale, Philip S.

    2006-01-01

    Multivariate genetic analysis was used to examine the genetic and environmental aetiology of the interrelationships of diverse linguistic skills. This study used data from a large sample of 4 1/2-year-old twins who were tested on measures assessing articulation, phonology, grammar, vocabulary, and verbal memory. Phenotypic analysis suggested two…

  14. A Globally Self-Consistent Model of Plate Motions Relative to the Hotspots for the Past 48 Million Years

    NASA Astrophysics Data System (ADS)

    Koivisto, E.; Gordon, R. G.

    2012-04-01

    of plate motions relative to the hotspots for the past 48 million years. To obtain the model, we use the tracks of the Hawaiian, Louisville, Tristan da Cunha, Réunion and Iceland hotspots. All the hotspot tracks used in this analysis are among the most widely accepted candidates for a deep mantle origin. The poles of rotation are estimated for ages corresponding to some key magnetic anomalies used in plate reconstructions. The new set of plate reconstructions presented here provide a firm basis for estimating absolute plate motions for the past 48 million years and, in particular, can be used to separate paleomagnetically determined apparent polar wander into the part due to plate motion and the part due to true polar wander.

  15. Central nervous system and muscular bundles preserved in a 240 million year old giant bristletail (Archaeognatha: Machilidae)

    PubMed Central

    Montagna, Matteo; Haug, Joachim T.; Strada, Laura; Haug, Carolin; Felber, Markus; Tintori, Andrea

    2017-01-01

    Among the incomparably diverse group of insects no cases of central nervous system (CNS) preservation have been so far described in compression fossils. A third of the fossil insects collected from a 240–239 million year old (Ma) level at Monte San Giorgio UNESCO World Heritage (Switzerland-Italy) underwent phosphatization, resulting in the extraordinary preservation of soft tissues. Here we describe Gigamachilis triassicus gen. et sp. nov. (Archaeognatha: Machiloidea: Machilidae) that, with an estimated total length of ~80 millimeters, represents the largest apterygote insect ever recorded. The holotype preserves: (i) components of the CNS represented by four abdominal ganglia, optic lobes with neuropils and compound retina; (ii) muscular bundles. Moreover, G. triassicus, possessing morphological features that prompt its assignment to the extant archaeognathan ingroup Machilidae, places the origin of modern lineages to Middle Triassic. Interestingly, at Monte San Giorgio, in the same stratigraphic unit the modern morphology of G. triassicus co-occurs with the ancient one represented by Dasyleptus triassicus (Archaeognatha: †Monura). Comparing these two types of body organization we provide a new reconstruction of the possible character evolution leading towards modern archaeognathan forms, suggesting the acquisition of novel features in a lineage of apterygote insects during the Permian or the Lower Triassic. PMID:28387236

  16. An 18 million year record of vegetation and climate change in northwestern Canada and Alaska: Tectonic and global climatic correlates

    USGS Publications Warehouse

    White, J.M.; Ager, T.A.; Adam, D.P.; Leopold, E.B.; Liu, Gaisheng; Jette, H.; Schweger, C.E.

    1997-01-01

    We reconstruct long-term vegetation/paleoclimatic trends, spanning the last 18 million years, in Alaska. Yukon and far western Northwest Territories. Twenty-one average percentage spectra for pollen and spores are assembled from eight surface/subsurface sections. The sections are dated independently or by correlation. Pollen and spore ratios indicate the direction of change in vegetation and climatic parameters growing season temperature (T(est)), tree canopy density (C(est)) and paludification at study sites (P(est)). A global warm peak ca. 15 Ma is shown by the abundance of thermophilous taxa, including Fagus and Quercus. A temperature decline immediately following 15 Ma parallels climatic reconstructions based on marine oxygen isotopes. Subsequent declines correlate to the Messinian event and the onset of late Pliocene Pleistocene glaciation. After 7 Ma herbs and shrubs become more important elements of the palynological assemblages, suggesting a more continental, colder/drier climate. However, a late Pliocene warm interval is evident. Vegetation/climatic changes during the early to late Miocene show synchrony with, and are most economically attributable to, global events. After 7 Ma, vegetation/climate change is attributed primarily to latest Miocene-to-Pleistocene uplift of the Alaska Range and St. Elias Mrs. The continuing influence of global climatic patterns is shown in the late Pliocene warm interval, despite uplift to the south. The opening of the Bering Strait ca. 3 Ma may have moderated the climate in the study area.

  17. Immunospecificity of albumin detected in 1.6 million-year-old fossils from Venta Micena in Orce, Granada, Spain.

    PubMed

    Borja, C; García-Pacheco, M; Olivares, E G; Scheuenstuhl, G; Lowenstein, J M

    1997-08-01

    The Orce skull fragment from southern Spain, dated at 1.6 Myr, has been a subject of heated controversy since it was first discovered in 1982. If it is hominid, as its discoverers contend, it is by far the oldest fossil hominid yet found in western Europe and implies that human populations settled this region much earlier than was previously realized. Numerous stone artifacts found at the Orce sites provide evidence that hominids were indeed present there in the Lower Pleistocene. Some paleontologists maintain that the 8 cm diameter occipital fragment is from a horse, not a hominid. Two independent investigations of the residual proteins in the skull were undertaken, one at the University of Granada in Spain, the other at the University of California, San Francisco. Two immunological methods of comparable sensitivity were employed for detection and species attribution of protein extracted from fossil bone: the Granada team used an enzyme-linked-immunosorbent assay (ELISA), and the UCSF team used a radioimmunoassay (RIA). Both teams obtained reactions characteristic of human albumin in the Orce skull and horse albumin in some of the horse fossils. These results support the lithic evidence that hominids were living in Andalusia 1.6 million years ago.

  18. Steady incision of Grand Canyon at the million year timeframe: a case for mantle-driven differential uplift

    USGS Publications Warehouse

    Crow, Ryan S; Karl Karlstrom,; Laura Crossey,; Richard Young,; Michael Ort,; Yemane Asmerom,; Victor Polyak,; Andrew Darling,

    2014-01-01

    The Grand Canyon region provides an excellent laboratory to examine the interplay between river incision, magmatism, and the geomorphic and tectonic processes that shape landscapes. Here we apply U-series, Ar–Ar, and cosmogenic burial dating of river terraces to examine spatial variations in incision rates along the 445 km length of the Colorado River through Grand Canyon. We also analyze strath terrace sequences that extend to heights of several hundred meters above the river, and integrate these with speleothem constrained maximum incision rates in several reaches to examine any temporal incision variations at the million-year time frame. This new high-resolution geochronology shows temporally steady long-term incision in any given reach of Grand Canyon but significant variations along its length from 160 m/Ma in the east to 101 m/Ma in the west. Spatial and temporal patterns of incision, and the long timescale of steady incision rule out models where geomorphic controls such as climate oscillations, bedrock strength, sediment load effects, or isostatic response to differential denudation are the first order drivers of canyon incision. The incision pattern is best explained by a model of Neogene and ongoing epeirogenic uplift due to an eastward propagating zone of increased upper mantle buoyancy that we infer from propagation of Neogene basaltic volcanism and a strong lateral gradient in modern upper mantle seismic structure.

  19. Ridge subduction sparked reorganization of the Pacific plate-mantle system 60-50 million years ago

    NASA Astrophysics Data System (ADS)

    Seton, Maria; Flament, Nicolas; Whittaker, Joanne; Müller, R. Dietmar; Gurnis, Michael; Bower, Dan J.

    2015-03-01

    A reorganization centered on the Pacific plate occurred ~53-47 million years ago. A "top-down" plate tectonic mechanism, complete subduction of the Izanagi plate, as opposed to a "bottom-up" mantle flow mechanism, has been proposed as the main driver. Verification based on marine geophysical observations is impossible as most ocean crust recording this event has been subducted. Using a forward modeling approach, which assimilates surface plate velocities and shallow thermal structure of slabs into mantle flow models, we show that complete Izanagi plate subduction and margin-wide slab detachment induced a major change in sub-Pacific mantle flow, from dominantly southward before 60 Ma to north-northeastward after 50 Ma. Our results agree with onshore geology, mantle tomography, and the inferred motion of the Hawaiian hot spot and are consistent with a plate tectonic process driving the rapid plate-mantle reorganization in the Pacific hemisphere between 60 and 50 Ma. This reorganization is reflected in tectonic changes in the Pacific and surrounding ocean basins.

  20. Ancient ecology of 15-million-year-old browsing mammals within C3 plant communities from Panama.

    PubMed

    MacFadden, Bruce J; Higgins, Pennilyn

    2004-06-01

    Middle Miocene mammals are known from approximately 15 million-year-old sediments exposed along the Panama Canal of Central America, a region that otherwise has an exceedingly poor terrestrial fossil record. These land mammals, which represent a part of the ancient terrestrial herbivore community, include an oreodont Merycochoerus matthewi, small camel-like protoceratid artiodactyl Paratoceras wardi, two horses Anchitherium clarencei and Archaeohippus sp., and two rhinos Menoceras barbouri and Floridaceras whitei. Bulk and serial carbon and oxygen isotope analyses of the tooth enamel carbonate allow reconstruction of the ancient climate and ecology of these fossil mammals. Ancient Panama had an equable climate with seasonal temperature and rainfall fluctuations less than those seen today. The middle Miocene terrestrial community consisted predominantly, or exclusively, of C3 plants, i.e., there is no evidence for C4 grasses. Statistically different mean carbon isotope values for the mammalian herbivores indicate niche partitioning of the C3 plant food resources. The range of individual carbon isotope analyses, i.e., delta13C from -15.9 to -10.1 per thousand, indicates herbivores feeding on diverse plants from different habitats with extrapolated delta13C values of -29.9 to -24.2 per thousand, possibly ranging from dense forest to more open country woodland. The ecological niches of individual mammalian herbivore species were differentiated either by diet or body size.

  1. "Intermetamorphic" developmental stages in 150 million-year-old achelatan lobsters--The case of the species tenera Oppel, 1862.

    PubMed

    Haug, Joachim T; Haug, Carolin

    2016-03-01

    We re-investigated the fossil species tenera Oppel, 1862, an achelatan lobster (traditionally named Palinurina tenera) found in 150 million years old limestones of southern Germany. All known specimens attributed to this species show a mixture of characters, which in modern forms occur either in larvae or post-larval juveniles. Hence these specimens provide insight into a phase in ontogeny that is no longer present in the developmental sequence of any modern achelatan lobster, as the latter ones skip this phase and replace it by a drastic metamorphosis. Comparable cases have been described earlier, yet did only comprise single stages or two successive ones at most. In the here described case four developmental stages are preserved. The reconstructed ontogeny of tenera therefore represents the currently best known sequence of an early achelatan lobster that covers this specific intermediate phase. The largest known stage most likely still represents an immature of a yet undiscovered adult. These findings support the interpretation that early achelatan lobsters developed in a more gradual ontogenetic sequence than modern forms. It furthermore demonstrates that it was even more gradual than anticipated previously.

  2. A New Chytridiomycete Fungus Intermixed with Crustacean Resting Eggs in a 407-Million-Year-Old Continental Freshwater Environment

    PubMed Central

    Goral, Tomasz; Longcore, Joyce E.; Olesen, Jørgen; Kenrick, Paul; Edgecombe, Gregory D.

    2016-01-01

    The 407-million-year-old Rhynie Chert (Scotland) contains the most intact fossilised remains of an early land-based ecosystem including plants, arthropods, fungi and other microorganisms. Although most studies have focused on the terrestrial component, fossilised freshwater environments provide critical insights into fungal-algal interactions and the earliest continental branchiopod crustaceans. Here we report interactions between an enigmatic organism and an exquisitely preserved fungus. The fungal reproductive structures are intermixed with exceptionally well-preserved globular spiny structures interpreted as branchiopod resting eggs. Confocal laser scanning microscopy enabled us to reconstruct the fungus and its possible mode of nutrition, the affinity of the resting eggs, and their spatial associations. The new fungus (Cultoraquaticus trewini gen. et sp. nov) is attributed to Chytridiomycota based on its size, consistent formation of papillae, and the presence of an internal rhizoidal system. It is the most pristine fossil Chytridiomycota known, especially in terms of rhizoidal development and closely resembles living species in the Rhizophydiales. The spiny resting eggs are attributed to the crustacean Lepidocaris rhyniensis, dating branchiopod adaptation to life in ephemeral pools to the Early Devonian. The new fungal interaction suggests that, as in modern freshwater environments, chytrids were important to the mobilisation of nutrients in early aquatic foodwebs. PMID:27973602

  3. Evidence of orbital forcing in 510 to 530 million year old shallow marine cycles, Utah and western Canada

    NASA Technical Reports Server (NTRS)

    Bond, Gerard C.; Beavan, John; Kominz, Michelle A.; Devlin, William

    1992-01-01

    Spectral analyses of two sequences of shallow marine sedimentary cycles that were deposited between 510 and 530 million years ago were completed. One sequence is from Middle Cambrian rocks in southern Utah and the other is from Upper Cambrian rocks in the southern Canadian Rockies. In spite of the antiquity of these strata, and even though there are differences in the age, location, and cycle facies between the two sequences, both records have distinct spectral peaks with surprisingly similar periodicities. A null model constructed to test for significance of the spectral peaks and circulatory in the methodology indicates that all but one of the spectral peaks are significant at the 90 percent confidence level. When the ratios between the statistically significant peaks are measured, we find a consistent relation to orbital forcing; specifically, the spectral peak ratios in both the Utah and Canadian examples imply that a significant amount of the variance in the cyclic records is driven by the short eccentricity (approximately 109 ky) and by the precessional (approximately 21 ky) components of the Earth's orbital variations. Neither section contains a significant component of variance at the period of the obliquity cycle, however.

  4. The ancient Britons: groundwater fauna survived extreme climate change over tens of millions of years across NW Europe.

    PubMed

    McInerney, Caitríona E; Maurice, Louise; Robertson, Anne L; Knight, Lee R F D; Arnscheidt, Jörg; Venditti, Chris; Dooley, James S G; Mathers, Thomas; Matthijs, Severine; Eriksson, Karin; Proudlove, Graham S; Hänfling, Bernd

    2014-03-01

    Global climate changes during the Cenozoic (65.5-0 Ma) caused major biological range shifts and extinctions. In northern Europe, for example, a pattern of few endemics and the dominance of wide-ranging species is thought to have been determined by the Pleistocene (2.59-0.01 Ma) glaciations. This study, in contrast, reveals an ancient subsurface fauna endemic to Britain and Ireland. Using a Bayesian phylogenetic approach, we found that two species of stygobitic invertebrates (genus Niphargus) have not only survived the entire Pleistocene in refugia but have persisted for at least 19.5 million years. Other Niphargus species form distinct cryptic taxa that diverged from their nearest continental relative between 5.6 and 1.0 Ma. The study also reveals an unusual biogeographical pattern in the Niphargus genus. It originated in north-west Europe approximately 87 Ma and underwent a gradual range expansion. Phylogenetic diversity and species age are highest in north-west Europe, suggesting resilience to extreme climate change and strongly contrasting the patterns seen in surface fauna. However, species diversity is highest in south-east Europe, indicating that once the genus spread to these areas (approximately 25 Ma), geomorphological and climatic conditions enabled much higher diversification. Our study highlights that groundwater ecosystems provide an important contribution to biodiversity and offers insight into the interactions between biological and climatic processes.

  5. Sea-level and deep-sea-temperature variability over the past 5.3 million years.

    PubMed

    Rohling, E J; Foster, G L; Grant, K M; Marino, G; Roberts, A P; Tamisiea, M E; Williams, F

    2014-04-24

    Ice volume (and hence sea level) and deep-sea temperature are key measures of global climate change. Sea level has been documented using several independent methods over the past 0.5 million years (Myr). Older periods, however, lack such independent validation; all existing records are related to deep-sea oxygen isotope (δ(18)O) data that are influenced by processes unrelated to sea level. For deep-sea temperature, only one continuous high-resolution (Mg/Ca-based) record exists, with related sea-level estimates, spanning the past 1.5 Myr. Here we present a novel sea-level reconstruction, with associated estimates of deep-sea temperature, which independently validates the previous 0-1.5 Myr reconstruction and extends it back to 5.3 Myr ago. We find that deep-sea temperature and sea level generally decreased through time, but distinctly out of synchrony, which is remarkable given the importance of ice-albedo feedbacks on the radiative forcing of climate. In particular, we observe a large temporal offset during the onset of Plio-Pleistocene ice ages, between a marked cooling step at 2.73 Myr ago and the first major glaciation at 2.15 Myr ago. Last, we tentatively infer that ice sheets may have grown largest during glacials with more modest reductions in deep-sea temperature.

  6. Reorganization of sea urchin gene regulatory networks at least 268 million years ago as revealed by oldest fossil cidaroid echinoid

    PubMed Central

    Thompson, Jeffrey R.; Petsios, Elizabeth; Davidson, Eric H.; Erkenbrack, Eric M.; Gao, Feng; Bottjer, David J.

    2015-01-01

    Echinoids, or sea urchins, are rare in the Palaeozoic fossil record, and thus the details regarding the early diversification of crown group echinoids are unclear. Here we report on the earliest probable crown group echinoid from the fossil record, recovered from Permian (Roadian-Capitanian) rocks of west Texas, which has important implications for the timing of the divergence of crown group echinoids. The presence of apophyses and rigidly sutured interambulacral areas with two columns of plates indicates this species is a cidaroid echinoid. The species, Eotiaris guadalupensis, n. sp. is therefore the earliest stem group cidaroid. The occurrence of this species in Roadian strata pushes back the divergence of cidaroids and euechinoids, the clades that comprise all living echinoids, to at least 268.8 Ma, ten million years older than the previously oldest known cidaroid. Furthermore, the genomic regulation of development in echinoids is amongst the best known, and this new species informs the timing of large-scale reorganization in echinoid gene regulatory networks that occurred at the cidaroid-euechinoid divergence, indicating that these changes took place by the Roadian stage of the Permian. PMID:26486232

  7. Steady incision of Grand Canyon at the million year timeframe: A case for mantle-driven differential uplift

    NASA Astrophysics Data System (ADS)

    Crow, Ryan; Karlstrom, Karl; Darling, Andrew; Crossey, Laura; Polyak, Victor; Granger, Darryl; Asmerom, Yemane; Schmandt, Brandon

    2014-07-01

    The Grand Canyon region provides an excellent laboratory to examine the interplay between river incision, magmatism, and the geomorphic and tectonic processes that shape landscapes. Here we apply U-series, Ar-Ar, and cosmogenic burial dating of river terraces to examine spatial variations in incision rates along the 445 km length of the Colorado River through Grand Canyon. We also analyze strath terrace sequences that extend to heights of several hundred meters above the river, and integrate these with speleothem constrained maximum incision rates in several reaches to examine any temporal incision variations at the million-year time frame. This new high-resolution geochronology shows temporally steady long-term incision in any given reach of Grand Canyon but significant variations along its length from 160 m/Ma in the east to 101 m/Ma in the west. Spatial and temporal patterns of incision, and the long timescale of steady incision rule out models where geomorphic controls such as climate oscillations, bedrock strength, sediment load effects, or isostatic response to differential denudation are the first order drivers of canyon incision. The incision pattern is best explained by a model of Neogene and ongoing epeirogenic uplift due to an eastward propagating zone of increased upper mantle buoyancy that we infer from propagation of Neogene basaltic volcanism and a strong lateral gradient in modern upper mantle seismic structure.

  8. A galaxy rapidly forming stars 700 million years after the Big Bang at redshift 7.51.

    PubMed

    Finkelstein, S L; Papovich, C; Dickinson, M; Song, M; Tilvi, V; Koekemoer, A M; Finkelstein, K D; Mobasher, B; Ferguson, H C; Giavalisco, M; Reddy, N; Ashby, M L N; Dekel, A; Fazio, G G; Fontana, A; Grogin, N A; Huang, J-S; Kocevski, D; Rafelski, M; Weiner, B J; Willner, S P

    2013-10-24

    Of several dozen galaxies observed spectroscopically that are candidates for having a redshift (z) in excess of seven, only five have had their redshifts confirmed via Lyman α emission, at z = 7.008, 7.045, 7.109, 7.213 and 7.215 (refs 1-4). The small fraction of confirmed galaxies may indicate that the neutral fraction in the intergalactic medium rises quickly at z > 6.5, given that Lyman α is resonantly scattered by neutral gas. The small samples and limited depth of previous observations, however, makes these conclusions tentative. Here we report a deep near-infrared spectroscopic survey of 43 photometrically-selected galaxies with z > 6.5. We detect a near-infrared emission line from only a single galaxy, confirming that some process is making Lyman α difficult to detect. The detected emission line at a wavelength of 1.0343 micrometres is likely to be Lyman α emission, placing this galaxy at a redshift z = 7.51, an epoch 700 million years after the Big Bang. This galaxy's colours are consistent with significant metal content, implying that galaxies become enriched rapidly. We calculate a surprisingly high star-formation rate of about 330 solar masses per year, which is more than a factor of 100 greater than that seen in the Milky Way. Such a galaxy is unexpected in a survey of our size, suggesting that the early Universe may harbour a larger number of intense sites of star formation than expected.

  9. 2.8 Million Years of Arctic Climate Change from Deep Drilling at Lake El'gygytgyn, NE Russia

    NASA Astrophysics Data System (ADS)

    Melles, M.; Brigham-Grette, J.; Minyuk, P.; Wennrich, V.; Nowaczyk, N.; DeConto, R.; Anderson, P.; Andreev, A.; Haltia-Hovi, E.; Kukkonen, M.; Lozhkin, A.; Rosén, P.; Tarasov, P.

    2012-12-01

    coupling, which could be due to a reduction of Antarctic Bottom Water formation and/or a significant global sea-level rise during times of WAIS decays. References: Melles M. et al. (2011): The El'gygytgyn Scientific Drilling Project - conquering Arctic challenges through continental drilling. - Scientific Drilling, 11: 29-40. Melles M. et al. (2012): 2.8 Million Years of Arctic Climate Change from Lake El'gygytgyn, NE Russia. - Science, 337: 315-320. Nolan M. (2012): Analysis of local AWS and NCEP/NCAR reanalysis data at Lake El'gygytgyn, and its implications for maintaining multi-year lake-ice covers. - Clim. Past Disc., 8: 1443-1483. Naish T. et al. (2009): Obliquity-paced Pliocene West Antarctic Ice Sheet oscillations. - Nature, 458: 322-329. Pollard D. and DeConto R.M. (2009): Modelling West Antarctic ice sheet growth and collapse through the past five million years. - Nature, 458: 329-332.

  10. Rates of dinosaur body mass evolution indicate 170 million years of sustained ecological innovation on the avian stem lineage.

    PubMed

    Benson, Roger B J; Campione, Nicolás E; Carrano, Matthew T; Mannion, Philip D; Sullivan, Corwin; Upchurch, Paul; Evans, David C

    2014-05-01

    Large-scale adaptive radiations might explain the runaway success of a minority of extant vertebrate clades. This hypothesis predicts, among other things, rapid rates of morphological evolution during the early history of major groups, as lineages invade disparate ecological niches. However, few studies of adaptive radiation have included deep time data, so the links between extant diversity and major extinct radiations are unclear. The intensively studied Mesozoic dinosaur record provides a model system for such investigation, representing an ecologically diverse group that dominated terrestrial ecosystems for 170 million years. Furthermore, with 10,000 species, extant dinosaurs (birds) are the most speciose living tetrapod clade. We assembled composite trees of 614-622 Mesozoic dinosaurs/birds, and a comprehensive body mass dataset using the scaling relationship of limb bone robustness. Maximum-likelihood modelling and the node height test reveal rapid evolutionary rates and a predominance of rapid shifts among size classes in early (Triassic) dinosaurs. This indicates an early burst niche-filling pattern and contrasts with previous studies that favoured gradualistic rates. Subsequently, rates declined in most lineages, which rarely exploited new ecological niches. However, feathered maniraptoran dinosaurs (including Mesozoic birds) sustained rapid evolution from at least the Middle Jurassic, suggesting that these taxa evaded the effects of niche saturation. This indicates that a long evolutionary history of continuing ecological innovation paved the way for a second great radiation of dinosaurs, in birds. We therefore demonstrate links between the predominantly extinct deep time adaptive radiation of non-avian dinosaurs and the phenomenal diversification of birds, via continuing rapid rates of evolution along the phylogenetic stem lineage. This raises the possibility that the uneven distribution of biodiversity results not just from large-scale extrapolation of

  11. Spintharus flavidus in the Caribbean—a 30 million year biogeographical history and radiation of a ‘widespread species’

    PubMed Central

    Dziki, Austin; Binford, Greta J.; Coddington, Jonathan A.

    2015-01-01

    The Caribbean island biota is characterized by high levels of endemism, the result of an interplay between colonization opportunities on islands and effective oceanic barriers among them. A relatively small percentage of the biota is represented by ‘widespread species,’ presumably taxa for which oceanic barriers are ineffective. Few studies have explored in detail the genetic structure of widespread Caribbean taxa. The cobweb spider Spintharus flavidus Hentz, 1850 (Theridiidae) is one of two described Spintharus species and is unique in being widely distributed from northern N. America to Brazil and throughout the Caribbean. As a taxonomic hypothesis, Spintharus “flavidus” predicts maintenance of gene flow among Caribbean islands, a prediction that seems contradicted by known S. flavidus biology, which suggests limited dispersal ability. As part of an extensive survey of Caribbean arachnids (project CarBio), we conducted the first molecular phylogenetic analysis of S. flavidus with the primary goal of testing the ‘widespread species’ hypothesis. Our results, while limited to three molecular loci, reject the hypothesis of a single widespread species. Instead this lineage seems to represent a radiation with at least 16 species in the Caribbean region. Nearly all are short range endemics with several distinct mainland groups and others are single island endemics. While limited taxon sampling, with a single specimen from S. America, constrains what we can infer about the biogeographical history of the lineage, clear patterns still emerge. Consistent with limited overwater dispersal, we find evidence for a single colonization of the Caribbean about 30 million years ago, coinciding with the timing of the GAARLandia landbridge hypothesis. In sum, S. “flavidus” is not a single species capable of frequent overwater dispersal, but rather a 30 my old radiation of single island endemics that provides preliminary support for a complex and contested geological

  12. Eighty-five million years of Pacific Ocean gyre ecosystem structure: long-term stability marked by punctuated change.

    PubMed

    Sibert, Elizabeth; Norris, Richard; Cuevas, Jose; Graves, Lana

    2016-05-25

    While the history of taxonomic diversification in open ocean lineages of ray-finned fish and elasmobranchs is increasingly known, the evolution of their roles within the open ocean ecosystem remains poorly understood. To assess the relative importance of these groups through time, we measured the accumulation rate of microfossil fish teeth and elasmobranch dermal denticles (ichthyoliths) in deep-sea sediment cores from the North and South Pacific gyres over the past 85 million years (Myr). We find three distinct and stable open ocean ecosystem structures, each defined by the relative and absolute abundance of elasmobranch and ray-finned fish remains. The Cretaceous Ocean (pre-66 Ma) was characterized by abundant elasmobranch denticles, but low abundances of fish teeth. The Palaeogene Ocean (66-20 Ma), initiated by the Cretaceous/Palaeogene mass extinction, had nearly four times the abundance of fish teeth compared with elasmobranch denticles. This Palaeogene Ocean structure remained stable during the Eocene greenhouse (50 Ma) and the Eocene-Oligocene glaciation (34 Ma), despite large changes in the overall accumulation of both groups during those intervals, suggesting that climate change is not a primary driver of ecosystem structure. Dermal denticles virtually disappeared from open ocean ichthyolith assemblages approximately 20 Ma, while fish tooth accumulation increased dramatically in variability, marking the beginning of the Modern Ocean. Together, these results suggest that open ocean fish community structure is stable on long timescales, independent of total production and climate change. The timing of the abrupt transitions between these states suggests that the transitions may be due to interactions with other, non-preserved pelagic consumer groups.

  13. Retention of functional genes for S19 ribosomal protein in both the mitochondrion and nucleus for over 60 million years.

    PubMed

    Atluri, Sruthi; Rampersad, Sarah N; Bonen, Linda

    2015-12-01

    Ribosomal protein genes occasionally undergo successful migration from the mitochondrion to the nucleus in flowering plants and we previously presented evidence that the S19 ribosomal protein gene (rps19) had been transferred to the nucleus in the common ancestor of Poaceae grasses. In many lineages, the mitochondrial copy was subsequently lost or pseudogenized, although in rice it was retained and the nuclear copy lost. We have now determined that functional rps19 genes are present in both the mitochondrion and nucleus in brome grass (Bromus inermis). The mitochondrion-located rps19 gene, which is immediately downstream of an rpl2 pseudogene, is transcribed and edited. The nuclear-located rps19 gene is also actively expressed and it possesses the same intron-containing hsp70-type presequence as its counterparts in other grasses, as well as shared derived amino acids within the S19 core. We conclude that this brome rps19 gene is derived from the same transfer event that occurred in the common ancestor of grasses at least 60 million years ago. In the oat lineage, a subsequent exon shuffling-type event has resulted in novel amino-terminal sequences replacing part of the hsp70 presequence, and in the barley lineage, there has been an additional DNA-mediated transfer of the mitochondrial rps19 gene and its flanking sequences, followed by relatively recent loss of the mitochondrion-located copy. The prolonged persistence of functional copies in both compartments, as evidenced by present-day brome, raises interesting questions about their respective roles.

  14. Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage

    PubMed Central

    Benson, Roger B. J.; Campione, Nicolás E.; Carrano, Matthew T.; Mannion, Philip D.; Sullivan, Corwin; Upchurch, Paul; Evans, David C.

    2014-01-01

    Large-scale adaptive radiations might explain the runaway success of a minority of extant vertebrate clades. This hypothesis predicts, among other things, rapid rates of morphological evolution during the early history of major groups, as lineages invade disparate ecological niches. However, few studies of adaptive radiation have included deep time data, so the links between extant diversity and major extinct radiations are unclear. The intensively studied Mesozoic dinosaur record provides a model system for such investigation, representing an ecologically diverse group that dominated terrestrial ecosystems for 170 million years. Furthermore, with 10,000 species, extant dinosaurs (birds) are the most speciose living tetrapod clade. We assembled composite trees of 614–622 Mesozoic dinosaurs/birds, and a comprehensive body mass dataset using the scaling relationship of limb bone robustness. Maximum-likelihood modelling and the node height test reveal rapid evolutionary rates and a predominance of rapid shifts among size classes in early (Triassic) dinosaurs. This indicates an early burst niche-filling pattern and contrasts with previous studies that favoured gradualistic rates. Subsequently, rates declined in most lineages, which rarely exploited new ecological niches. However, feathered maniraptoran dinosaurs (including Mesozoic birds) sustained rapid evolution from at least the Middle Jurassic, suggesting that these taxa evaded the effects of niche saturation. This indicates that a long evolutionary history of continuing ecological innovation paved the way for a second great radiation of dinosaurs, in birds. We therefore demonstrate links between the predominantly extinct deep time adaptive radiation of non-avian dinosaurs and the phenomenal diversification of birds, via continuing rapid rates of evolution along the phylogenetic stem lineage. This raises the possibility that the uneven distribution of biodiversity results not just from large-scale extrapolation

  15. Are patterns in nutrient limitation belowground consistent with those aboveground: Results from a 4 million year chronosequence

    USGS Publications Warehouse

    Reed, S.C.; Vitousek, P.M.; Cleveland, C.C.

    2011-01-01

    Accurately predicting the effects of global change on net carbon (C) exchange between terrestrial ecosystems and the atmosphere requires a more complete understanding of how nutrient availability regulates both plant growth and heterotrophic soil respiration. Models of soil development suggest that the nature of nutrient limitation changes over the course of ecosystem development, transitioning from nitrogen (N) limitation in 'young' sites to phosphorus (P) limitation in 'old' sites. However, previous research has focused primarily on plant responses to added nutrients, and the applicability of nutrient limitation-soil development models to belowground processes has not been thoroughly investigated. Here, we assessed the effects of nutrients on soil C cycling in three different forests that occupy a 4 million year substrate age chronosequence where tree growth is N limited at the youngest site, co-limited by N and P at the intermediate-aged site, and P limited at the oldest site. Our goal was to use short-term laboratory soil C manipulations (using 14C-labeled substrates) and longer-term intact soil core incubations to compare belowground responses to fertilization with aboveground patterns. When nutrients were applied with labile C (sucrose), patterns of microbial nutrient limitation were similar to plant patterns: microbial activity was limited more by N than by P in the young site, and P was more limiting than N in the old site. However, in the absence of C additions, increased respiration of native soil organic matter only occurred with simultaneous additions of N and P. Taken together, these data suggest that altered nutrient inputs into ecosystems could have dissimilar effects on C cycling above- and belowground, that nutrients may differentially affect of the fate of different soil C pools, and that future changes to the net C balance of terrestrial ecosystems will be partially regulated by soil nutrient status. ?? 2010 US Government.

  16. Baseline intrinsic flammability of Earth’s ecosystems estimated from paleoatmospheric oxygen over the past 350 million years

    PubMed Central

    Belcher, Claire M.; Yearsley, Jonathan M.; Hadden, Rory M.; McElwain, Jennifer C.; Rein, Guillermo

    2010-01-01

    Atmospheric oxygen (O2) is estimated to have varied greatly throughout Earth’s history and has been capable of influencing wildfire activity wherever fuel and ignition sources were present. Fires consume huge quantities of biomass in all ecosystems and play an important role in biogeochemical cycles. This means that understanding the influence of O2 on past fire activity has far-reaching consequences for the evolution of life and Earth’s biodiversity over geological timescales. We have used a strong electrical ignition source to ignite smoldering fires, and we measured their self-sustaining propagation in atmospheres of different oxygen concentrations. These data have been used to build a model that we use to estimate the baseline intrinsic flammability of Earth’s ecosystems according to variations in O2 over the past 350 million years (Ma). Our aim is to highlight times in Earth’s history when fire has been capable of influencing the Earth system. We reveal that fire activity would be greatly suppressed below 18.5% O2, entirely switched off below 16% O2, and rapidly enhanced between 19–22% O2. We show that fire activity and, therefore, its influence on the Earth system would have been high during the Carboniferous (350–300 Ma) and Cretaceous (145–65 Ma) periods; intermediate in the Permian (299–251 Ma), Late Triassic (285–201 Ma), and Jurassic (201–145 Ma) periods; and surprisingly low to lacking in the Early–Middle Triassic period between 250–240 Ma. These baseline variations in Earth’s flammability must be factored into our understanding of past vegetation, biodiversity, evolution, and biogeochemical cycles. PMID:21149686

  17. The OAO heat pipes - 8 1/2 years of flight data

    NASA Technical Reports Server (NTRS)

    Harwell, W.; Mcintosh, R.

    1981-01-01

    Heat pipe performance data taken during the 8 1/2 years of flight of the OAO-C (Copernicus) spacecraft are presented. Three fixed conductance heat pipes (FCHP), each with different wicking concepts (axial groove, pedestal artery, and self-priming spiral artery), and one variable conductance heat pipe (VCHP) are onboard. Aluminum tubes (1/2 in. diameter) rolled into a 48 in. loop containing ultra high purity ammonia as the heat transfer fluid comprise all FCHP, whose purpose is to circumferentially isothermalize the central tube housing the telescope. The VCHP is a hot, non-wicked reservoir concept including a composite artery and methanol heat transfer fluid, and is used to maintain the temperature of the onboard processor. Flight thermal data analysis reveals that no degradation in performance occurred since launch and agrees well with pre-flight data; the onboard processor still shows an offset in control range of 4 F, and the pipes perform the same after 8 1/2 years in orbit.

  18. Reconstructing the diet of a 505-million-year-old arthropod: Sidneyia inexpectans from the Burgess Shale fauna.

    PubMed

    Zacaï, Axelle; Vannier, Jean; Lerosey-Aubril, Rudy

    2016-03-01

    The feeding ecology of the 505-million-year-old arthropod Sidneyia inexpectans from the middle Cambrian (Series 3, Stage 5) Burgess Shale fauna (British Columbia, Canada) is revealed by three lines of evidence: the structure of its digestive system, the fossilized contents of its gut and the functional anatomy of its appendages. The digestive tract of Sidneyia is straight, tubular and relatively narrow in the trunk region. It is enlarged into a pear-shaped area in the cephalic region and stretches notably to form a large pocket in the abdomen. The mouth is ventral, posteriorly directed and leads to the midgut via a short tubular structure interpreted as the oesophagus. Anteriorly, three pairs of glands with internal, branching tubular structures open into the digestive tract. These glands have equivalents in various Cambrian arthropod taxa (e.g. naraoiids) and modern arthropods. Their primary function was most likely to digest and assimilate food. The abdominal pocket of Sidneyia concentrates undigested skeletal elements and various residues. It is interpreted here as the functional analogue of the stercoral pocket of some extant terrestrial arachnids (e.g. Araneae, Solifugae), whose primary function is to store food residuals and excretory material until defecation. Analysis of the gut contents indicates that Sidneyia fed largely on small ptychopariid trilobites, brachiopods, possibly agnostids, worms and other undetermined animals. Sidneyia was primarily a durophagous carnivore with predatory and/or scavenging habits, feeding on small invertebrates that lived at the water-sediment interface. There is no evidence for selective feeding. Its food items (e.g. living prey or dead material) were grasped and manipulated ventrally by its anterior appendages, then macerated into ingestible fragments and conveyed to the mouth via the converging action of strong molar-like gnathobases. Digestion probably took place within the anterior midgut via enzymes secreted in the

  19. Phosphogenesis in the 2460 and 2728 million-year-old banded iron formations as evidence for biological cycling of phosphate in the early biosphere

    PubMed Central

    Li, Yi-Liang; Sun, Si; Chan, Lung S

    2013-01-01

    The banded iron formation deposited during the first 2 billion years of Earth's history holds the key to understanding the interplay between the geosphere and the early biosphere at large geological timescales. The earliest ore-scale phosphorite depositions formed almost at ∼2.0–2.2 billion years ago bear evidence for the earliest bloom of aerobic life. The cycling of nutrient phosphorus and how it constrained primary productivity in the anaerobic world of Archean–Palaeoproterozoic eons are still open questions. The controversy centers about whether the precipitation of ultrafine ferric oxyhydroxide due to the microbial Fe(II) oxidation in oceans earlier than 1.9 billion years substantially sequestrated phosphate, and whether this process significantly limited the primary productivity of the early biosphere. In this study, we report apatite radial flowers of a few micrometers in the 2728 million-year-old Abitibi banded iron formation and the 2460 million-year-old Kuruman banded iron formation and their similarities to those in the 535 million-year-old Lower Cambrian phosphorite. The lithology of the 535 Million-year-old phosphorite as a biosignature bears abundant biomarkers that reveal the possible similar biogeochemical cycling of phosphorus in the Later Archean and Palaeoproterozoic oceans. These apatite radial flowers represent the primary precipitation of phosphate derived from the phytoplankton blooms in the euphotic zones of Neoarchean and Palaoeproterozoic oceans. The unbiased distributions of the apatite radial flowers within sub-millimeter bands do not support the idea of an Archean Crisis of Phosphate. This is the first report of the microbial mediated mineralization of phosphorus before the Great Oxidation Event when the whole biosphere was still dominated by anaerobic microorganisms. PMID:23404127

  20. Phosphogenesis in the 2460 and 2728 million-year-old banded iron formations as evidence for biological cycling of phosphate in the early biosphere.

    PubMed

    Li, Yi-Liang; Sun, Si; Chan, Lung S

    2012-01-01

    The banded iron formation deposited during the first 2 billion years of Earth's history holds the key to understanding the interplay between the geosphere and the early biosphere at large geological timescales. The earliest ore-scale phosphorite depositions formed almost at ∼2.0-2.2 billion years ago bear evidence for the earliest bloom of aerobic life. The cycling of nutrient phosphorus and how it constrained primary productivity in the anaerobic world of Archean-Palaeoproterozoic eons are still open questions. The controversy centers about whether the precipitation of ultrafine ferric oxyhydroxide due to the microbial Fe(II) oxidation in oceans earlier than 1.9 billion years substantially sequestrated phosphate, and whether this process significantly limited the primary productivity of the early biosphere. In this study, we report apatite radial flowers of a few micrometers in the 2728 million-year-old Abitibi banded iron formation and the 2460 million-year-old Kuruman banded iron formation and their similarities to those in the 535 million-year-old Lower Cambrian phosphorite. The lithology of the 535 Million-year-old phosphorite as a biosignature bears abundant biomarkers that reveal the possible similar biogeochemical cycling of phosphorus in the Later Archean and Palaeoproterozoic oceans. These apatite radial flowers represent the primary precipitation of phosphate derived from the phytoplankton blooms in the euphotic zones of Neoarchean and Palaoeproterozoic oceans. The unbiased distributions of the apatite radial flowers within sub-millimeter bands do not support the idea of an Archean Crisis of Phosphate. This is the first report of the microbial mediated mineralization of phosphorus before the Great Oxidation Event when the whole biosphere was still dominated by anaerobic microorganisms.

  1. Nordic biological specimen banks as basis for studies of cancer causes and control--more than 2 million sample donors, 25 million person years and 100,000 prospective cancers.

    PubMed

    Pukkala, Eero; Andersen, Aage; Berglund, Göran; Gislefoss, Randi; Gudnason, Vilmundur; Hallmans, Göran; Jellum, Egil; Jousilahti, Pekka; Knekt, Paul; Koskela, Pentti; Kyyrönen, P Pentti; Lenner, Per; Luostarinen, Tapio; Löve, Arthur; Ogmundsdóttir, Helga; Stattin, Pär; Tenkanen, Leena; Tryggvadóttir, Laufey; Virtamo, Jarmo; Wadell, Göran; Widell, Anders; Lehtinen, Matti; Dillner, Joakim

    2007-01-01

    The Nordic countries have a long tradition of large-scale biobanking and comprehensive, population-based health data registries linkable on unique personal identifiers, enabling follow-up studies spanning many decades. Joint Nordic biobank-based studies provide unique opportunities for longitudinal molecular epidemiological research. The purpose of the present paper is to describe the possibilities for such joint studies, by describing some of the major Nordic biobank cohorts with a standardised calculation of the cancer incidence in these cohorts. Altogether two million donors have since 1966 donated more than four million biological samples, stored at -20 degrees C to -135 degrees C, to 17 biobank cohorts in Finland, Iceland, Norway and Sweden. As a result of joint database handling principles, the accuracy of personal identifiers and completeness of follow-up for vital status in all participating biobanks was improved. Thereafter, the cancer incidence was determined using follow-up through the national cancer registries. Biobanks based on random samples of population typically showed slightly lower cancer incidence rates than the general population, presumably due to better participation rates among health-conscious subjects. On the other hand, biobanks including samples for viral screening or clinical testing showed 1.5 to 2.1 fold increased incidence of cancer. This excess was very high immediately after sampling, but for some cancer sites remained elevated for years after clinical sampling. So far, more than 100 000 malignant neoplasms have occurred after sample donation, and the annual increase of the cancer cases in these cohorts is about 10 000. The estimates on the population-representativity of the biobanks will assist in interpretation of generalizability of results of future studies based on these samples, and the systematic tabulations of numbers of cancer cases will serve in study power estimations. The present paper summarizes optimal study designs

  2. Prevalence and genotypes of Giardia duodenalis in 1-2 year old dairy cattle.

    PubMed

    Trout, James M; Santín, Mónica; Greiner, Ellis C; Fayer, Ronald

    2006-09-10

    To determine the prevalence of Giardia genotypes in 12-24 month old dairy heifers, fecal specimens were collected from two farms each in Vermont, New York, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. Specimens, cleaned of fecal debris and concentrated using CsCl density gradient centrifugation, were subjected to PCR and DNA sequence analysis. Prevalence of Giardia infection, ranged from 11% to 75% on 14 farms with an average prevalence of 36% (204 positive cattle out of 571 examined). DNA sequence analysis of the 16S rRNA gene revealed 91% of the 204 Giardia isolates were Assemblage E, and 9% were Assemblage A. The prevalence of these genotypes varied greatly from farm to farm, with four farms having exclusively Assemblage E Giardia. Overall, Assemblage E was present in 33% of all animals tested and Assemblage A was present in 3% of the animals. Thus, while many of the heifers were infected with a genotype that is not known to be infectious for humans, 1-2 year old heifers on 10 of 14 farms did harbor zoonotic Assemblage A Giardia. Therefore, heifers cannot be overlooked as a potential source of human infectious cysts in the environment, with some farms representing a much higher risk than others.

  3. Multiple paleopolyploidizations during the evolution of the Compositae reveal parallel patterns of duplicate gene retention after millions of years.

    PubMed

    Barker, Michael S; Kane, Nolan C; Matvienko, Marta; Kozik, Alexander; Michelmore, Richard W; Knapp, Steven J; Rieseberg, Loren H

    2008-11-01

    Of the approximately 250,000 species of flowering plants, nearly one in ten are members of the Compositae (Asteraceae), a diverse family found in almost every habitat on all continents except Antarctica. With an origin in the mid Eocene, the Compositae is also a relatively young family with remarkable diversifications during the last 40 My. Previous cytologic and systematic investigations suggested that paleopolyploidy may have occurred in at least one Compositae lineage, but a recent analysis of genomic data was equivocal. We tested for evidence of paleopolyploidy in the evolutionary history of the family using recently available expressed sequence tag (EST) data from the Compositae Genome Project. Combined with data available on GenBank, we analyzed nearly 1 million ESTs from 18 species representing seven genera and four tribes. Our analyses revealed at least three ancient whole-genome duplications in the Compositae-a paleopolyploidization shared by all analyzed taxa and placed near the origin of the family just prior to the rapid radiation of its tribes and independent genome duplications near the base of the tribes Mutisieae and Heliantheae. These results are consistent with previous research implicating paleopolyploidy in the evolution and diversification of the Heliantheae. Further, we observed parallel retention of duplicate genes from the basal Compositae genome duplication across all tribes, despite divergence times of 33-38 My among these lineages. This pattern of retention was also repeated for the paleologs from the Heliantheae duplication. Intriguingly, the categories of genes retained in duplicate were substantially different from those in Arabidopsis. In particular, we found that genes annotated to structural components or cellular organization Gene Ontology categories were significantly enriched among paleologs, whereas genes associated with transcription and other regulatory functions were significantly underrepresented. Our results suggest that

  4. Multiple Paleopolyploidizations during the Evolution of the Compositae Reveal Parallel Patterns of Duplicate Gene Retention after Millions of Years

    PubMed Central

    Barker, Michael S.; Kane, Nolan C.; Matvienko, Marta; Kozik, Alexander; Michelmore, Richard W.; Knapp, Steven J.; Rieseberg, Loren H.

    2008-01-01

    Of the approximately 250,000 species of flowering plants, nearly one in ten are members of the Compositae (Asteraceae), a diverse family found in almost every habitat on all continents except Antarctica. With an origin in the mid Eocene, the Compositae is also a relatively young family with remarkable diversifications during the last 40 My. Previous cytologic and systematic investigations suggested that paleopolyploidy may have occurred in at least one Compositae lineage, but a recent analysis of genomic data was equivocal. We tested for evidence of paleopolyploidy in the evolutionary history of the family using recently available expressed sequence tag (EST) data from the Compositae Genome Project. Combined with data available on GenBank, we analyzed nearly 1 million ESTs from 18 species representing seven genera and four tribes. Our analyses revealed at least three ancient whole-genome duplications in the Compositae—a paleopolyploidization shared by all analyzed taxa and placed near the origin of the family just prior to the rapid radiation of its tribes and independent genome duplications near the base of the tribes Mutisieae and Heliantheae. These results are consistent with previous research implicating paleopolyploidy in the evolution and diversification of the Heliantheae. Further, we observed parallel retention of duplicate genes from the basal Compositae genome duplication across all tribes, despite divergence times of 33–38 My among these lineages. This pattern of retention was also repeated for the paleologs from the Heliantheae duplication. Intriguingly, the categories of genes retained in duplicate were substantially different from those in Arabidopsis. In particular, we found that genes annotated to structural components or cellular organization Gene Ontology categories were significantly enriched among paleologs, whereas genes associated with transcription and other regulatory functions were significantly underrepresented. Our results suggest

  5. The Orbital Distribution of Meteorites Based on High Temperature Thermoluminescence. 2; Orbits of Meteoroids over the Last Million Years

    NASA Technical Reports Server (NTRS)

    Benoit, P. H.; Akridge, J. M. C.; Sears, D. W. G.

    2001-01-01

    We use high temperature TL data to evaluate perihelia of Antarctic meteorites. Perihelion has been constant for the ordinary chondrites over the last 40,000-100,000 years. Additional information is contained in the original extended abstract.

  6. 85 million years of pelagic ecosystem evolution: Pacific Ocean deep-sea ichthyolith records reveal fish community dynamics and a long-term decline in sharks

    NASA Astrophysics Data System (ADS)

    Sibert, E. C.; Norris, R. D.; Cuevas, J. M.; Graves, L. G.

    2015-12-01

    The structure and productivity of open ocean consumers has undergone major changes over the past 85 million years. Here, we present the first long-term detailed records of pelagic fish and sharks utilizing the record of ichthyoliths (teeth and dermal scales) from the deep Pacific Ocean. While the North and South Pacific Oceans show similar patterns throughout the 85 million year history, the North Pacific ichthyolith accumulation is significantly higher than the South Pacific, suggesting that the basin has been a more productive region for tens of millions of years. Fish and sharks were not abundant in the Pacific gyres until ~75 million years ago (Ma) suggesting that neither group was quantitatively important in oligotrophic pelagic food webs prior to the latest Cretaceous. Relative to ray-finned fish, sharks were common in the ancient ocean. Most ichthyolith assemblages have >50% shark dermal scales (denticles), but denticle abundance has been declining in both absolute and relative abundance since the Cretaceous-Paleogene (K/Pg) mass extinction. The accumulation rate of ichthyoliths of both sharks and ray-finned fish was highest in the Early Eocene, during the peak of the Cenozoic 'greenhouse' climate where production of shark dermal denticles and fish teeth increased almost five times over Paleocene production rates. Ichthyolith fluxes fell with cooler climates in the later Eocene and Oligocene, but fish production is almost always higher than in the Cretaceous and Paleocene reflecting the expanded ecological roles and importance of pelagic fish in marine ecosystems. Shark denticle production fell to less than half that of the Cretaceous by 20 Ma when it dropped abruptly to near-zero levels. Currently denticles make up <2% of the ichthyolith assemblages when present at all. Ecologically, pelagic sharks appear to be falling as major pelagic consumers over the Late Cretaceous and Cenozoic, and particularly over the past 20 Ma, perhaps reflecting demographic

  7. Drosophila Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

    PubMed Central

    Leung, Wilson; Shaffer, Christopher D.; Reed, Laura K.; Smith, Sheryl T.; Barshop, William; Dirkes, William; Dothager, Matthew; Lee, Paul; Wong, Jeannette; Xiong, David; Yuan, Han; Bedard, James E. J.; Machone, Joshua F.; Patterson, Seantay D.; Price, Amber L.; Turner, Bryce A.; Robic, Srebrenka; Luippold, Erin K.; McCartha, Shannon R.; Walji, Tezin A.; Walker, Chelsea A.; Saville, Kenneth; Abrams, Marita K.; Armstrong, Andrew R.; Armstrong, William; Bailey, Robert J.; Barberi, Chelsea R.; Beck, Lauren R.; Blaker, Amanda L.; Blunden, Christopher E.; Brand, Jordan P.; Brock, Ethan J.; Brooks, Dana W.; Brown, Marie; Butzler, Sarah C.; Clark, Eric M.; Clark, Nicole B.; Collins, Ashley A.; Cotteleer, Rebecca J.; Cullimore, Peterson R.; Dawson, Seth G.; Docking, Carter T.; Dorsett, Sasha L.; Dougherty, Grace A.; Downey, Kaitlyn A.; Drake, Andrew P.; Earl, Erica K.; Floyd, Trevor G.; Forsyth, Joshua D.; Foust, Jonathan D.; Franchi, Spencer L.; Geary, James F.; Hanson, Cynthia K.; Harding, Taylor S.; Harris, Cameron B.; Heckman, Jonathan M.; Holderness, Heather L.; Howey, Nicole A.; Jacobs, Dontae A.; Jewell, Elizabeth S.; Kaisler, Maria; Karaska, Elizabeth A.; Kehoe, James L.; Koaches, Hannah C.; Koehler, Jessica; Koenig, Dana; Kujawski, Alexander J.; Kus, Jordan E.; Lammers, Jennifer A.; Leads, Rachel R.; Leatherman, Emily C.; Lippert, Rachel N.; Messenger, Gregory S.; Morrow, Adam T.; Newcomb, Victoria; Plasman, Haley J.; Potocny, Stephanie J.; Powers, Michelle K.; Reem, Rachel M.; Rennhack, Jonathan P.; Reynolds, Katherine R.; Reynolds, Lyndsey A.; Rhee, Dong K.; Rivard, Allyson B.; Ronk, Adam J.; Rooney, Meghan B.; Rubin, Lainey S.; Salbert, Luke R.; Saluja, Rasleen K.; Schauder, Taylor; Schneiter, Allison R.; Schulz, Robert W.; Smith, Karl E.; Spencer, Sarah; Swanson, Bryant R.; Tache, Melissa A.; Tewilliager, Ashley A.; Tilot, Amanda K.; VanEck, Eve; Villerot, Matthew M.; Vylonis, Megan B.; Watson, David T.; Wurzler, Juliana A.; Wysocki, Lauren M.; Yalamanchili, Monica; Zaborowicz, Matthew A.; Emerson, Julia A.; Ortiz, Carlos; Deuschle, Frederic J.; DiLorenzo, Lauren A.; Goeller, Katie L.; Macchi, Christopher R.; Muller, Sarah E.; Pasierb, Brittany D.; Sable, Joseph E.; Tucci, Jessica M.; Tynon, Marykathryn; Dunbar, David A.; Beken, Levent H.; Conturso, Alaina C.; Danner, Benjamin L.; DeMichele, Gabriella A.; Gonzales, Justin A.; Hammond, Maureen S.; Kelley, Colleen V.; Kelly, Elisabeth A.; Kulich, Danielle; Mageeney, Catherine M.; McCabe, Nikie L.; Newman, Alyssa M.; Spaeder, Lindsay A.; Tumminello, Richard A.; Revie, Dennis; Benson, Jonathon M.; Cristostomo, Michael C.; DaSilva, Paolo A.; Harker, Katherine S.; Jarrell, Jenifer N.; Jimenez, Luis A.; Katz, Brandon M.; Kennedy, William R.; Kolibas, Kimberly S.; LeBlanc, Mark T.; Nguyen, Trung T.; Nicolas, Daniel S.; Patao, Melissa D.; Patao, Shane M.; Rupley, Bryan J.; Sessions, Bridget J.; Weaver, Jennifer A.; Goodman, Anya L.; Alvendia, Erica L.; Baldassari, Shana M.; Brown, Ashley S.; Chase, Ian O.; Chen, Maida; Chiang, Scott; Cromwell, Avery B.; Custer, Ashley F.; DiTommaso, Tia M.; El-Adaimi, Jad; Goscinski, Nora C.; Grove, Ryan A.; Gutierrez, Nestor; Harnoto, Raechel S.; Hedeen, Heather; Hong, Emily L.; Hopkins, Barbara L.; Huerta, Vilma F.; Khoshabian, Colin; LaForge, Kristin M.; Lee, Cassidy T.; Lewis, Benjamin M.; Lydon, Anniken M.; Maniaci, Brian J.; Mitchell, Ryan D.; Morlock, Elaine V.; Morris, William M.; Naik, Priyanka; Olson, Nicole C.; Osterloh, Jeannette M.; Perez, Marcos A.; Presley, Jonathan D.; Randazzo, Matt J.; Regan, Melanie K.; Rossi, Franca G.; Smith, Melanie A.; Soliterman, Eugenia A.; Sparks, Ciani J.; Tran, Danny L.; Wan, Tiffany; Welker, Anne A.; Wong, Jeremy N.; Sreenivasan, Aparna; Youngblom, Jim; Adams, Andrew; Alldredge, Justin; Bryant, Ashley; Carranza, David; Cifelli, Alyssa; Coulson, Kevin; Debow, Calise; Delacruz, Noelle; Emerson, Charlene; Farrar, Cassandra; Foret, Don; Garibay, Edgar; Gooch, John; Heslop, Michelle; Kaur, Sukhjit; Khan, Ambreen; Kim, Van; Lamb, Travis; Lindbeck, Peter; Lucas, Gabi; Macias, Elizabeth; Martiniuc, Daniela; Mayorga, Lissett; Medina, Joseph; Membreno, Nelson; Messiah, Shady; Neufeld, Lacey; Nguyen, San Francisco; Nichols, Zachary; Odisho, George; Peterson, Daymon; Rodela, Laura; Rodriguez, Priscilla; Rodriguez, Vanessa; Ruiz, Jorge; Sherrill, Will; Silva, Valeria; Sparks, Jeri; Statton, Geeta; Townsend, Ashley; Valdez, Isabel; Waters, Mary; Westphal, Kyle; Winkler, Stacey; Zumkehr, Joannee; DeJong, Randall J.; Hoogewerf, Arlene J.; Ackerman, Cheri M.; Armistead, Isaac O.; Baatenburg, Lara; Borr, Matthew J.; Brouwer, Lindsay K.; Burkhart, Brandon J.; Bushhouse, Kelsey T.; Cesko, Lejla; Choi, Tiffany Y. Y.; Cohen, Heather; Damsteegt, Amanda M.; Darusz, Jess M.; Dauphin, Cory M.; Davis, Yelena P.; Diekema, Emily J.; Drewry, Melissa; Eisen, Michelle E. M.; Faber, Hayley M.; Faber, Katherine J.; Feenstra, Elizabeth; Felzer-Kim, Isabella T.; Hammond, Brandy L.; Hendriksma, Jesse; Herrold, Milton R.; Hilbrands, Julia A.; Howell, Emily J.; Jelgerhuis, Sarah A.; Jelsema, Timothy R.; Johnson, Benjamin K.; Jones, Kelly K.; Kim, Anna; Kooienga, Ross D.; Menyes, Erika E.; Nollet, Eric A.; Plescher, Brittany E.; Rios, Lindsay; Rose, Jenny L.; Schepers, Allison J.; Scott, Geoff; Smith, Joshua R.; Sterling, Allison M.; Tenney, Jenna C.; Uitvlugt, Chris; VanDyken, Rachel E.; VanderVennen, Marielle; Vue, Samantha; Kokan, Nighat P.; Agbley, Kwabea; Boham, Sampson K.; Broomfield, Daniel; Chapman, Kayla; Dobbe, Ali; Dobbe, Ian; Harrington, William; Ibrahem, Marwan; Kennedy, Andre; Koplinsky, Chad A.; Kubricky, Cassandra; Ladzekpo, Danielle; Pattison, Claire; Ramirez, Roman E.; Wande, Lucia; Woehlke, Sarah; Wawersik, Matthew; Kiernan, Elizabeth; Thompson, Jeffrey S.; Banker, Roxanne; Bartling, Justina R.; Bhatiya, Chinmoy I.; Boudoures, Anna L.; Christiansen, Lena; Fosselman, Daniel S.; French, Kristin M.; Gill, Ishwar S.; Havill, Jessen T.; Johnson, Jaelyn L.; Keny, Lauren J.; Kerber, John M.; Klett, Bethany M.; Kufel, Christina N.; May, Francis J.; Mecoli, Jonathan P.; Merry, Callie R.; Meyer, Lauren R.; Miller, Emily G.; Mullen, Gregory J.; Palozola, Katherine C.; Pfeil, Jacob J.; Thomas, Jessica G.; Verbofsky, Evan M.; Spana, Eric P.; Agarwalla, Anant; Chapman, Julia; Chlebina, Ben; Chong, Insun; Falk, I.N.; Fitzgibbons, John D.; Friedman, Harrison; Ighile, Osagie; Kim, Andrew J.; Knouse, Kristin A.; Kung, Faith; Mammo, Danny; Ng, Chun Leung; Nikam, Vinayak S.; Norton, Diana; Pham, Philip; Polk, Jessica W.; Prasad, Shreya; Rankin, Helen; Ratliff, Camille D.; Scala, Victoria; Schwartz, Nicholas U.; Shuen, Jessica A.; Xu, Amy; Xu, Thomas Q.; Zhang, Yi; Rosenwald, Anne G.; Burg, Martin G.; Adams, Stephanie J.; Baker, Morgan; Botsford, Bobbi; Brinkley, Briana; Brown, Carter; Emiah, Shadie; Enoch, Erica; Gier, Chad; Greenwell, Alyson; Hoogenboom, Lindsay; Matthews, Jordan E.; McDonald, Mitchell; Mercer, Amanda; Monsma, Nicholaus; Ostby, Kristine; Ramic, Alen; Shallman, Devon; Simon, Matthew; Spencer, Eric; Tomkins, Trisha; Wendland, Pete; Wylie, Anna; Wolyniak, Michael J.; Robertson, Gregory M.; Smith, Samuel I.; DiAngelo, Justin R.; Sassu, Eric D.; Bhalla, Satish C.; Sharif, Karim A.; Choeying, Tenzin; Macias, Jason S.; Sanusi, Fareed; Torchon, Karvyn; Bednarski, April E.; Alvarez, Consuelo J.; Davis, Kristen C.; Dunham, Carrie A.; Grantham, Alaina J.; Hare, Amber N.; Schottler, Jennifer; Scott, Zackary W.; Kuleck, Gary A.; Yu, Nicole S.; Kaehler, Marian M.; Jipp, Jacob; Overvoorde, Paul J.; Shoop, Elizabeth; Cyrankowski, Olivia; Hoover, Betsy; Kusner, Matt; Lin, Devry; Martinov, Tijana; Misch, Jonathan; Salzman, Garrett; Schiedermayer, Holly; Snavely, Michael; Zarrasola, Stephanie; Parrish, Susan; Baker, Atlee; Beckett, Alissa; Belella, Carissa; Bryant, Julie; Conrad, Turner; Fearnow, Adam; Gomez, Carolina; Herbstsomer, Robert A.; Hirsch, Sarah; Johnson, Christen; Jones, Melissa; Kabaso, Rita; Lemmon, Eric; Vieira, Carolina Marques dos Santos; McFarland, Darryl; McLaughlin, Christopher; Morgan, Abbie; Musokotwane, Sepo; Neutzling, William; Nietmann, Jana; Paluskievicz, Christina; Penn, Jessica; Peoples, Emily; Pozmanter, Caitlin; Reed, Emily; Rigby, Nichole; Schmidt, Lasse; Shelton, Micah; Shuford, Rebecca; Tirasawasdichai, Tiara; Undem, Blair; Urick, Damian; Vondy, Kayla; Yarrington, Bryan; Eckdahl, Todd T.; Poet, Jeffrey L.; Allen, Alica B.; Anderson, John E.; Barnett, Jason M.; Baumgardner, Jordan S.; Brown, Adam D.; Carney, Jordan E.; Chavez, Ramiro A.; Christgen, Shelbi L.; Christie, Jordan S.; Clary, Andrea N.; Conn, Michel A.; Cooper, Kristen M.; Crowley, Matt J.; Crowley, Samuel T.; Doty, Jennifer S.; Dow, Brian A.; Edwards, Curtis R.; Elder, Darcie D.; Fanning, John P.; Janssen, Bridget M.; Lambright, Anthony K.; Lane, Curtiss E.; Limle, Austin B.; Mazur, Tammy; McCracken, Marly R.; McDonough, Alexa M.; Melton, Amy D.; Minnick, Phillip J.; Musick, Adam E.; Newhart, William H.; Noynaert, Joseph W.; Ogden, Bradley J.; Sandusky, Michael W.; Schmuecker, Samantha M.; Shipman, Anna L.; Smith, Anna L.; Thomsen, Kristen M.; Unzicker, Matthew R.; Vernon, William B.; Winn, Wesley W.; Woyski, Dustin S.; Zhu, Xiao; Du, Chunguang; Ament, Caitlin; Aso, Soham; Bisogno, Laura Simone; Caronna, Jason; Fefelova, Nadezhda; Lopez, Lenin; Malkowitz, Lorraine; Marra, Jonathan; Menillo, Daniella; Obiorah, Ifeanyi; Onsarigo, Eric Nyabeta; Primus, Shekerah; Soos, Mahdi; Tare, Archana; Zidan, Ameer; Jones, Christopher J.; Aronhalt, Todd; Bellush, James M.; Burke, Christa; DeFazio, Steve; Does, Benjamin R.; Johnson, Todd D.; Keysock, Nicholas; Knudsen, Nelson H.; Messler, James; Myirski, Kevin; Rekai, Jade Lea; Rempe, Ryan Michael; Salgado, Michael S.; Stagaard, Erica; Starcher, Justin R.; Waggoner, Andrew W.; Yemelyanova, Anastasia K.; Hark, Amy T.; Bertolet, Anne; Kuschner, Cyrus E.; Parry, Kesley; Quach, Michael; Shantzer, Lindsey; Shaw, Mary E.; Smith, Mary A.; Glenn, Omolara; Mason, Portia; Williams, Charlotte; Key, S. Catherine Silver; Henry, Tyneshia C. P.; Johnson, Ashlee G.; White, Jackie X.; Haberman, Adam; Asinof, Sam; Drumm, Kelly; Freeburg, Trip; Safa, Nadia; Schultz, Darrin; Shevin, Yakov; Svoronos, Petros; Vuong, Tam; Wellinghoff, Jules; Hoopes, Laura L. M.; Chau, Kim M.; Ward, Alyssa; Regisford, E. Gloria C.; Augustine, LaJerald; Davis-Reyes, Brionna; Echendu, Vivienne; Hales, Jasmine; Ibarra, Sharon; Johnson, Lauriaun; Ovu, Steven; Braverman, John M.; Bahr, Thomas J.; Caesar, Nicole M.; Campana, Christopher; Cassidy, Daniel W.; Cognetti, Peter A.; English, Johnathan D.; Fadus, Matthew C.; Fick, Cameron N.; Freda, Philip J.; Hennessy, Bryan M.; Hockenberger, Kelsey; Jones, Jennifer K.; King, Jessica E.; Knob, Christopher R.; Kraftmann, Karen J.; Li, Linghui; Lupey, Lena N.; Minniti, Carl J.; Minton, Thomas F.; Moran, Joseph V.; Mudumbi, Krishna; Nordman, Elizabeth C.; Puetz, William J.; Robinson, Lauren M.; Rose, Thomas J.; Sweeney, Edward P.; Timko, Ashley S.; Paetkau, Don W.; Eisler, Heather L.; Aldrup, Megan E.; Bodenberg, Jessica M.; Cole, Mara G.; Deranek, Kelly M.; DeShetler, Megan; Dowd, Rose M.; Eckardt, Alexandra K.; Ehret, Sharon C.; Fese, Jessica; Garrett, Amanda D.; Kammrath, Anna; Kappes, Michelle L.; Light, Morgan R.; Meier, Anne C.; O’Rouke, Allison; Perella, Mallory; Ramsey, Kimberley; Ramthun, Jennifer R.; Reilly, Mary T.; Robinett, Deirdre; Rossi, Nadine L.; Schueler, Mary Grace; Shoemaker, Emma; Starkey, Kristin M.; Vetor, Ashley; Vrable, Abby; Chandrasekaran, Vidya; Beck, Christopher; Hatfield, Kristen R.; Herrick, Douglas A.; Khoury, Christopher B.; Lea, Charlotte; Louie, Christopher A.; Lowell, Shannon M.; Reynolds, Thomas J.; Schibler, Jeanine; Scoma, Alexandra H.; Smith-Gee, Maxwell T.; Tuberty, Sarah; Smith, Christopher D.; Lopilato, Jane E.; Hauke, Jeanette; Roecklein-Canfield, Jennifer A.; Corrielus, Maureen; Gilman, Hannah; Intriago, Stephanie; Maffa, Amanda; Rauf, Sabya A.; Thistle, Katrina; Trieu, Melissa; Winters, Jenifer; Yang, Bib; Hauser, Charles R.; Abusheikh, Tariq; Ashrawi, Yara; Benitez, Pedro; Boudreaux, Lauren R.; Bourland, Megan; Chavez, Miranda; Cruz, Samantha; Elliott, GiNell; Farek, Jesse R.; Flohr, Sarah; Flores, Amanda H.; Friedrichs, Chelsey; Fusco, Zach; Goodwin, Zane; Helmreich, Eric; Kiley, John; Knepper, John Mark; Langner, Christine; Martinez, Megan; Mendoza, Carlos; Naik, Monal; Ochoa, Andrea; Ragland, Nicolas; Raimey, England; Rathore, Sunil; Reza, Evangelina; Sadovsky, Griffin; Seydoux, Marie-Isabelle B.; Smith, Jonathan E.; Unruh, Anna K.; Velasquez, Vicente; Wolski, Matthew W.; Gosser, Yuying; Govind, Shubha; Clarke-Medley, Nicole; Guadron, Leslie; Lau, Dawn; Lu, Alvin; Mazzeo, Cheryl; Meghdari, Mariam; Ng, Simon; Pamnani, Brad; Plante, Olivia; Shum, Yuki Kwan Wa; Song, Roy; Johnson, Diana E.; Abdelnabi, Mai; Archambault, Alexi; Chamma, Norma; Gaur, Shailly; Hammett, Deborah; Kandahari, Adrese; Khayrullina, Guzal; Kumar, Sonali; Lawrence, Samantha; Madden, Nigel; Mandelbaum, Max; Milnthorp, Heather; Mohini, Shiv; Patel, Roshni; Peacock, Sarah J.; Perling, Emily; Quintana, Amber; Rahimi, Michael; Ramirez, Kristen; Singhal, Rishi; Weeks, Corinne; Wong, Tiffany; Gillis, Aubree T.; Moore, Zachary D.; Savell, Christopher D.; Watson, Reece; Mel, Stephanie F.; Anilkumar, Arjun A.; Bilinski, Paul; Castillo, Rostislav; Closser, Michael; Cruz, Nathalia M.; Dai, Tiffany; Garbagnati, Giancarlo F.; Horton, Lanor S.; Kim, Dongyeon; Lau, Joyce H.; Liu, James Z.; Mach, Sandy D.; Phan, Thu A.; Ren, Yi; Stapleton, Kenneth E.; Strelitz, Jean M.; Sunjed, Ray; Stamm, Joyce; Anderson, Morgan C.; Bonifield, Bethany Grace; Coomes, Daniel; Dillman, Adam; Durchholz, Elaine J.; Fafara-Thompson, Antoinette E.; Gross, Meleah J.; Gygi, Amber M.; Jackson, Lesley E.; Johnson, Amy; Kocsisova, Zuzana; Manghelli, Joshua L.; McNeil, Kylie; Murillo, Michael; Naylor, Kierstin L.; Neely, Jessica; Ogawa, Emmy E.; Rich, Ashley; Rogers, Anna; Spencer, J. Devin; Stemler, Kristina M.; Throm, Allison A.; Van Camp, Matt; Weihbrecht, Katie; Wiles, T. Aaron; Williams, Mallory A.; Williams, Matthew; Zoll, Kyle; Bailey, Cheryl; Zhou, Leming; Balthaser, Darla M.; Bashiri, Azita; Bower, Mindy E.; Florian, Kayla A.; Ghavam, Nazanin; Greiner-Sosanko, Elizabeth S.; Karim, Helmet; Mullen, Victor W.; Pelchen, Carly E.; Yenerall, Paul M.; Zhang, Jiayu; Rubin, Michael R.; Arias-Mejias, Suzette M.; Bermudez-Capo, Armando G.; Bernal-Vega, Gabriela V.; Colon-Vazquez, Mariela; Flores-Vazquez, Arelys; Gines-Rosario, Mariela; Llavona-Cartagena, Ivan G.; Martinez-Rodriguez, Javier O.; Ortiz-Fuentes, Lionel; Perez-Colomba, Eliezer O.; Perez-Otero, Joseph; Rivera, Elisandra; Rodriguez-Giron, Luke J.; Santiago-Sanabria, Arnaldo J.; Senquiz-Gonzalez, Andrea M.; delValle, Frank R. Soto; Vargas-Franco, Dorianmarie; Velázquez-Soto, Karla I.; Zambrana-Burgos, Joan D.; Martinez-Cruzado, Juan Carlos; Asencio-Zayas, Lillyann; Babilonia-Figueroa, Kevin; Beauchamp-Pérez, Francis D.; Belén-Rodríguez, Juliana; Bracero-Quiñones, Luciann; Burgos-Bula, Andrea P.; Collado-Méndez, Xavier A.; Colón-Cruz, Luis R.; Correa-Muller, Ana I.; Crooke-Rosado, Jonathan L.; Cruz-García, José M.; Defendini-Ávila, Marianna; Delgado-Peraza, Francheska M.; Feliciano-Cancela, Alex J.; Gónzalez-Pérez, Valerie M.; Guiblet, Wilfried; Heredia-Negrón, Aldo; Hernández-Muñiz, Jennifer; Irizarry-González, Lourdes N.; Laboy-Corales, Ángel L.; Llaurador-Caraballo, Gabriela A.; Marín-Maldonado, Frances; Marrero-Llerena, Ulises; Martell-Martínez, Héctor A.; Martínez-Traverso, Idaliz M.; Medina-Ortega, Kiara N.; Méndez-Castellanos, Sonya G.; Menéndez-Serrano, Krizia C.; Morales-Caraballo, Carol I.; Ortiz-DeChoudens, Saryleine; Ortiz-Ortiz, Patricia; Pagán-Torres, Hendrick; Pérez-Afanador, Diana; Quintana-Torres, Enid M.; Ramírez-Aponte, Edwin G.; Riascos-Cuero, Carolina; Rivera-Llovet, Michelle S.; Rivera-Pagán, Ingrid T.; Rivera-Vicéns, Ramón E.; Robles-Juarbe, Fabiola; Rodríguez-Bonilla, Lorraine; Rodríguez-Echevarría, Brian O.; Rodríguez-García, Priscila M.; Rodríguez-Laboy, Abneris E.; Rodríguez-Santiago, Susana; Rojas-Vargas, Michael L.; Rubio-Marrero, Eva N.; Santiago-Colón, Albeliz; Santiago-Ortiz, Jorge L.; Santos-Ramos, Carlos E.; Serrano-González, Joseline; Tamayo-Figueroa, Alina M.; Tascón-Peñaranda, Edna P.; Torres-Castillo, José L.; Valentín-Feliciano, Nelson A.; Valentín-Feliciano, Yashira M.; Vargas-Barreto, Nadyan M.; Vélez-Vázquez, Miguel; Vilanova-Vélez, Luis R.; Zambrana-Echevarría, Cristina; MacKinnon, Christy; Chung, Hui-Min; Kay, Chris; Pinto, Anthony; Kopp, Olga R.; Burkhardt, Joshua; Harward, Chris; Allen, Robert; Bhat, Pavan; Chang, Jimmy Hsiang-Chun; Chen, York; Chesley, Christopher; Cohn, Dara; DuPuis, David; Fasano, Michael; Fazzio, Nicholas; Gavinski, Katherine; Gebreyesus, Heran; Giarla, Thomas; Gostelow, Marcus; Greenstein, Rachel; Gunasinghe, Hashini; Hanson, Casey; Hay, Amanda; He, Tao Jian; Homa, Katie; Howe, Ruth; Howenstein, Jeff; Huang, Henry; Khatri, Aaditya; Kim, Young Lu; Knowles, Olivia; Kong, Sarah; Krock, Rebecca; Kroll, Matt; Kuhn, Julia; Kwong, Matthew; Lee, Brandon; Lee, Ryan; Levine, Kevin; Li, Yedda; Liu, Bo; Liu, Lucy; Liu, Max; Lousararian, Adam; Ma, Jimmy; Mallya, Allyson; Manchee, Charlie; Marcus, Joseph; McDaniel, Stephen; Miller, Michelle L.; Molleston, Jerome M.; Diez, Cristina Montero; Ng, Patrick; Ngai, Natalie; Nguyen, Hien; Nylander, Andrew; Pollack, Jason; Rastogi, Suchita; Reddy, Himabindu; Regenold, Nathaniel; Sarezky, Jon; Schultz, Michael; Shim, Jien; Skorupa, Tara; Smith, Kenneth; Spencer, Sarah J.; Srikanth, Priya; Stancu, Gabriel; Stein, Andrew P.; Strother, Marshall; Sudmeier, Lisa; Sun, Mengyang; Sundaram, Varun; Tazudeen, Noor; Tseng, Alan; Tzeng, Albert; Venkat, Rohit; Venkataram, Sandeep; Waldman, Leah; Wang, Tracy; Yang, Hao; Yu, Jack Y.; Zheng, Yin; Preuss, Mary L.; Garcia, Angelica; Juergens, Matt; Morris, Robert W.; Nagengast, Alexis A.; Azarewicz, Julie; Carr, Thomas J.; Chichearo, Nicole; Colgan, Mike; Donegan, Megan; Gardner, Bob; Kolba, Nik; Krumm, Janice L.; Lytle, Stacey; MacMillian, Laurell; Miller, Mary; Montgomery, Andrew; Moretti, Alysha; Offenbacker, Brittney; Polen, Mike; Toth, John; Woytanowski, John; Kadlec, Lisa; Crawford, Justin; Spratt, Mary L.; Adams, Ashley L.; Barnard, Brianna K.; Cheramie, Martin N.; Eime, Anne M.; Golden, Kathryn L.; Hawkins, Allyson P.; Hill, Jessica E.; Kampmeier, Jessica A.; Kern, Cody D.; Magnuson, Emily E.; Miller, Ashley R.; Morrow, Cody M.; Peairs, Julia C.; Pickett, Gentry L.; Popelka, Sarah A.; Scott, Alexis J.; Teepe, Emily J.; TerMeer, Katie A.; Watchinski, Carmen A.; Watson, Lucas A.; Weber, Rachel E.; Woodard, Kate A.; Barnard, Daron C.; Appiah, Isaac; Giddens, Michelle M.; McNeil, Gerard P.; Adebayo, Adeola; Bagaeva, Kate; Chinwong, Justina; Dol, Chrystel; George, Eunice; Haltaufderhyde, Kirk; Haye, Joanna; Kaur, Manpreet; Semon, Max; Serjanov, Dmitri; Toorie, Anika; Wilson, Christopher; Riddle, Nicole C.; Buhler, Jeremy; Mardis, Elaine R.

    2015-01-01

    The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu. PMID:25740935

  8. Drosophila muller f elements maintain a distinct set of genomic properties over 40 million years of evolution.

    PubMed

    Leung, Wilson; Shaffer, Christopher D; Reed, Laura K; Smith, Sheryl T; Barshop, William; Dirkes, William; Dothager, Matthew; Lee, Paul; Wong, Jeannette; Xiong, David; Yuan, Han; Bedard, James E J; Machone, Joshua F; Patterson, Seantay D; Price, Amber L; Turner, Bryce A; Robic, Srebrenka; Luippold, Erin K; McCartha, Shannon R; Walji, Tezin A; Walker, Chelsea A; Saville, Kenneth; Abrams, Marita K; Armstrong, Andrew R; Armstrong, William; Bailey, Robert J; Barberi, Chelsea R; Beck, Lauren R; Blaker, Amanda L; Blunden, Christopher E; Brand, Jordan P; Brock, Ethan J; Brooks, Dana W; Brown, Marie; Butzler, Sarah C; Clark, Eric M; Clark, Nicole B; Collins, Ashley A; Cotteleer, Rebecca J; Cullimore, Peterson R; Dawson, Seth G; Docking, Carter T; Dorsett, Sasha L; Dougherty, Grace A; Downey, Kaitlyn A; Drake, Andrew P; Earl, Erica K; Floyd, Trevor G; Forsyth, Joshua D; Foust, Jonathan D; Franchi, Spencer L; Geary, James F; Hanson, Cynthia K; Harding, Taylor S; Harris, Cameron B; Heckman, Jonathan M; Holderness, Heather L; Howey, Nicole A; Jacobs, Dontae A; Jewell, Elizabeth S; Kaisler, Maria; Karaska, Elizabeth A; Kehoe, James L; Koaches, Hannah C; Koehler, Jessica; Koenig, Dana; Kujawski, Alexander J; Kus, Jordan E; Lammers, Jennifer A; Leads, Rachel R; Leatherman, Emily C; Lippert, Rachel N; Messenger, Gregory S; Morrow, Adam T; Newcomb, Victoria; Plasman, Haley J; Potocny, Stephanie J; Powers, Michelle K; Reem, Rachel M; Rennhack, Jonathan P; Reynolds, Katherine R; Reynolds, Lyndsey A; Rhee, Dong K; Rivard, Allyson B; Ronk, Adam J; Rooney, Meghan B; Rubin, Lainey S; Salbert, Luke R; Saluja, Rasleen K; Schauder, Taylor; Schneiter, Allison R; Schulz, Robert W; Smith, Karl E; Spencer, Sarah; Swanson, Bryant R; Tache, Melissa A; Tewilliager, Ashley A; Tilot, Amanda K; VanEck, Eve; Villerot, Matthew M; Vylonis, Megan B; Watson, David T; Wurzler, Juliana A; Wysocki, Lauren M; Yalamanchili, Monica; Zaborowicz, Matthew A; Emerson, Julia A; Ortiz, Carlos; Deuschle, Frederic J; DiLorenzo, Lauren A; Goeller, Katie L; Macchi, Christopher R; Muller, Sarah E; Pasierb, Brittany D; Sable, Joseph E; Tucci, Jessica M; Tynon, Marykathryn; Dunbar, David A; Beken, Levent H; Conturso, Alaina C; Danner, Benjamin L; DeMichele, Gabriella A; Gonzales, Justin A; Hammond, Maureen S; Kelley, Colleen V; Kelly, Elisabeth A; Kulich, Danielle; Mageeney, Catherine M; McCabe, Nikie L; Newman, Alyssa M; Spaeder, Lindsay A; Tumminello, Richard A; Revie, Dennis; Benson, Jonathon M; Cristostomo, Michael C; DaSilva, Paolo A; Harker, Katherine S; Jarrell, Jenifer N; Jimenez, Luis A; Katz, Brandon M; Kennedy, William R; Kolibas, Kimberly S; LeBlanc, Mark T; Nguyen, Trung T; Nicolas, Daniel S; Patao, Melissa D; Patao, Shane M; Rupley, Bryan J; Sessions, Bridget J; Weaver, Jennifer A; Goodman, Anya L; Alvendia, Erica L; Baldassari, Shana M; Brown, Ashley S; Chase, Ian O; Chen, Maida; Chiang, Scott; Cromwell, Avery B; Custer, Ashley F; DiTommaso, Tia M; El-Adaimi, Jad; Goscinski, Nora C; Grove, Ryan A; Gutierrez, Nestor; Harnoto, Raechel S; Hedeen, Heather; Hong, Emily L; Hopkins, Barbara L; Huerta, Vilma F; Khoshabian, Colin; LaForge, Kristin M; Lee, Cassidy T; Lewis, Benjamin M; Lydon, Anniken M; Maniaci, Brian J; Mitchell, Ryan D; Morlock, Elaine V; Morris, William M; Naik, Priyanka; Olson, Nicole C; Osterloh, Jeannette M; Perez, Marcos A; Presley, Jonathan D; Randazzo, Matt J; Regan, Melanie K; Rossi, Franca G; Smith, Melanie A; Soliterman, Eugenia A; Sparks, Ciani J; Tran, Danny L; Wan, Tiffany; Welker, Anne A; Wong, Jeremy N; Sreenivasan, Aparna; Youngblom, Jim; Adams, Andrew; Alldredge, Justin; Bryant, Ashley; Carranza, David; Cifelli, Alyssa; Coulson, Kevin; Debow, Calise; Delacruz, Noelle; Emerson, Charlene; Farrar, Cassandra; Foret, Don; Garibay, Edgar; Gooch, John; Heslop, Michelle; Kaur, Sukhjit; Khan, Ambreen; Kim, Van; Lamb, Travis; Lindbeck, Peter; Lucas, Gabi; Macias, Elizabeth; Martiniuc, Daniela; Mayorga, Lissett; Medina, Joseph; Membreno, Nelson; Messiah, Shady; Neufeld, Lacey; Nguyen, San Francisco; Nichols, Zachary; Odisho, George; Peterson, Daymon; Rodela, Laura; Rodriguez, Priscilla; Rodriguez, Vanessa; Ruiz, Jorge; Sherrill, Will; Silva, Valeria; Sparks, Jeri; Statton, Geeta; Townsend, Ashley; Valdez, Isabel; Waters, Mary; Westphal, Kyle; Winkler, Stacey; Zumkehr, Joannee; DeJong, Randall J; Hoogewerf, Arlene J; Ackerman, Cheri M; Armistead, Isaac O; Baatenburg, Lara; Borr, Matthew J; Brouwer, Lindsay K; Burkhart, Brandon J; Bushhouse, Kelsey T; Cesko, Lejla; Choi, Tiffany Y Y; Cohen, Heather; Damsteegt, Amanda M; Darusz, Jess M; Dauphin, Cory M; Davis, Yelena P; Diekema, Emily J; Drewry, Melissa; Eisen, Michelle E M; Faber, Hayley M; Faber, Katherine J; Feenstra, Elizabeth; Felzer-Kim, Isabella T; Hammond, Brandy L; Hendriksma, Jesse; Herrold, Milton R; Hilbrands, Julia A; Howell, Emily J; Jelgerhuis, Sarah A; Jelsema, Timothy R; Johnson, Benjamin K; Jones, Kelly K; Kim, Anna; Kooienga, Ross D; Menyes, Erika E; Nollet, Eric A; Plescher, Brittany E; Rios, Lindsay; Rose, Jenny L; Schepers, Allison J; Scott, Geoff; Smith, Joshua R; Sterling, Allison M; Tenney, Jenna C; Uitvlugt, Chris; VanDyken, Rachel E; VanderVennen, Marielle; Vue, Samantha; Kokan, Nighat P; Agbley, Kwabea; Boham, Sampson K; Broomfield, Daniel; Chapman, Kayla; Dobbe, Ali; Dobbe, Ian; Harrington, William; Ibrahem, Marwan; Kennedy, Andre; Koplinsky, Chad A; Kubricky, Cassandra; Ladzekpo, Danielle; Pattison, Claire; Ramirez, Roman E; Wande, Lucia; Woehlke, Sarah; Wawersik, Matthew; Kiernan, Elizabeth; Thompson, Jeffrey S; Banker, Roxanne; Bartling, Justina R; Bhatiya, Chinmoy I; Boudoures, Anna L; Christiansen, Lena; Fosselman, Daniel S; French, Kristin M; Gill, Ishwar S; Havill, Jessen T; Johnson, Jaelyn L; Keny, Lauren J; Kerber, John M; Klett, Bethany M; Kufel, Christina N; May, Francis J; Mecoli, Jonathan P; Merry, Callie R; Meyer, Lauren R; Miller, Emily G; Mullen, Gregory J; Palozola, Katherine C; Pfeil, Jacob J; Thomas, Jessica G; Verbofsky, Evan M; Spana, Eric P; Agarwalla, Anant; Chapman, Julia; Chlebina, Ben; Chong, Insun; Falk, I N; Fitzgibbons, John D; Friedman, Harrison; Ighile, Osagie; Kim, Andrew J; Knouse, Kristin A; Kung, Faith; Mammo, Danny; Ng, Chun Leung; Nikam, Vinayak S; Norton, Diana; Pham, Philip; Polk, Jessica W; Prasad, Shreya; Rankin, Helen; Ratliff, Camille D; Scala, Victoria; Schwartz, Nicholas U; Shuen, Jessica A; Xu, Amy; Xu, Thomas Q; Zhang, Yi; Rosenwald, Anne G; Burg, Martin G; Adams, Stephanie J; Baker, Morgan; Botsford, Bobbi; Brinkley, Briana; Brown, Carter; Emiah, Shadie; Enoch, Erica; Gier, Chad; Greenwell, Alyson; Hoogenboom, Lindsay; Matthews, Jordan E; McDonald, Mitchell; Mercer, Amanda; Monsma, Nicholaus; Ostby, Kristine; Ramic, Alen; Shallman, Devon; Simon, Matthew; Spencer, Eric; Tomkins, Trisha; Wendland, Pete; Wylie, Anna; Wolyniak, Michael J; Robertson, Gregory M; Smith, Samuel I; DiAngelo, Justin R; Sassu, Eric D; Bhalla, Satish C; Sharif, Karim A; Choeying, Tenzin; Macias, Jason S; Sanusi, Fareed; Torchon, Karvyn; Bednarski, April E; Alvarez, Consuelo J; Davis, Kristen C; Dunham, Carrie A; Grantham, Alaina J; Hare, Amber N; Schottler, Jennifer; Scott, Zackary W; Kuleck, Gary A; Yu, Nicole S; Kaehler, Marian M; Jipp, Jacob; Overvoorde, Paul J; Shoop, Elizabeth; Cyrankowski, Olivia; Hoover, Betsy; Kusner, Matt; Lin, Devry; Martinov, Tijana; Misch, Jonathan; Salzman, Garrett; Schiedermayer, Holly; Snavely, Michael; Zarrasola, Stephanie; Parrish, Susan; Baker, Atlee; Beckett, Alissa; Belella, Carissa; Bryant, Julie; Conrad, Turner; Fearnow, Adam; Gomez, Carolina; Herbstsomer, Robert A; Hirsch, Sarah; Johnson, Christen; Jones, Melissa; Kabaso, Rita; Lemmon, Eric; Vieira, Carolina Marques Dos Santos; McFarland, Darryl; McLaughlin, Christopher; Morgan, Abbie; Musokotwane, Sepo; Neutzling, William; Nietmann, Jana; Paluskievicz, Christina; Penn, Jessica; Peoples, Emily; Pozmanter, Caitlin; Reed, Emily; Rigby, Nichole; Schmidt, Lasse; Shelton, Micah; Shuford, Rebecca; Tirasawasdichai, Tiara; Undem, Blair; Urick, Damian; Vondy, Kayla; Yarrington, Bryan; Eckdahl, Todd T; Poet, Jeffrey L; Allen, Alica B; Anderson, John E; Barnett, Jason M; Baumgardner, Jordan S; Brown, Adam D; Carney, Jordan E; Chavez, Ramiro A; Christgen, Shelbi L; Christie, Jordan S; Clary, Andrea N; Conn, Michel A; Cooper, Kristen M; Crowley, Matt J; Crowley, Samuel T; Doty, Jennifer S; Dow, Brian A; Edwards, Curtis R; Elder, Darcie D; Fanning, John P; Janssen, Bridget M; Lambright, Anthony K; Lane, Curtiss E; Limle, Austin B; Mazur, Tammy; McCracken, Marly R; McDonough, Alexa M; Melton, Amy D; Minnick, Phillip J; Musick, Adam E; Newhart, William H; Noynaert, Joseph W; Ogden, Bradley J; Sandusky, Michael W; Schmuecker, Samantha M; Shipman, Anna L; Smith, Anna L; Thomsen, Kristen M; Unzicker, Matthew R; Vernon, William B; Winn, Wesley W; Woyski, Dustin S; Zhu, Xiao; Du, Chunguang; Ament, Caitlin; Aso, Soham; Bisogno, Laura Simone; Caronna, Jason; Fefelova, Nadezhda; Lopez, Lenin; Malkowitz, Lorraine; Marra, Jonathan; Menillo, Daniella; Obiorah, Ifeanyi; Onsarigo, Eric Nyabeta; Primus, Shekerah; Soos, Mahdi; Tare, Archana; Zidan, Ameer; Jones, Christopher J; Aronhalt, Todd; Bellush, James M; Burke, Christa; DeFazio, Steve; Does, Benjamin R; Johnson, Todd D; Keysock, Nicholas; Knudsen, Nelson H; Messler, James; Myirski, Kevin; Rekai, Jade Lea; Rempe, Ryan Michael; Salgado, Michael S; Stagaard, Erica; Starcher, Justin R; Waggoner, Andrew W; Yemelyanova, Anastasia K; Hark, Amy T; Bertolet, Anne; Kuschner, Cyrus E; Parry, Kesley; Quach, Michael; Shantzer, Lindsey; Shaw, Mary E; Smith, Mary A; Glenn, Omolara; Mason, Portia; Williams, Charlotte; Key, S Catherine Silver; Henry, Tyneshia C P; Johnson, Ashlee G; White, Jackie X; Haberman, Adam; Asinof, Sam; Drumm, Kelly; Freeburg, Trip; Safa, Nadia; Schultz, Darrin; Shevin, Yakov; Svoronos, Petros; Vuong, Tam; Wellinghoff, Jules; Hoopes, Laura L M; Chau, Kim M; Ward, Alyssa; Regisford, E Gloria C; Augustine, LaJerald; Davis-Reyes, Brionna; Echendu, Vivienne; Hales, Jasmine; Ibarra, Sharon; Johnson, Lauriaun; Ovu, Steven; Braverman, John M; Bahr, Thomas J; Caesar, Nicole M; Campana, Christopher; Cassidy, Daniel W; Cognetti, Peter A; English, Johnathan D; Fadus, Matthew C; Fick, Cameron N; Freda, Philip J; Hennessy, Bryan M; Hockenberger, Kelsey; Jones, Jennifer K; King, Jessica E; Knob, Christopher R; Kraftmann, Karen J; Li, Linghui; Lupey, Lena N; Minniti, Carl J; Minton, Thomas F; Moran, Joseph V; Mudumbi, Krishna; Nordman, Elizabeth C; Puetz, William J; Robinson, Lauren M; Rose, Thomas J; Sweeney, Edward P; Timko, Ashley S; Paetkau, Don W; Eisler, Heather L; Aldrup, Megan E; Bodenberg, Jessica M; Cole, Mara G; Deranek, Kelly M; DeShetler, Megan; Dowd, Rose M; Eckardt, Alexandra K; Ehret, Sharon C; Fese, Jessica; Garrett, Amanda D; Kammrath, Anna; Kappes, Michelle L; Light, Morgan R; Meier, Anne C; O'Rouke, Allison; Perella, Mallory; Ramsey, Kimberley; Ramthun, Jennifer R; Reilly, Mary T; Robinett, Deirdre; Rossi, Nadine L; Schueler, Mary Grace; Shoemaker, Emma; Starkey, Kristin M; Vetor, Ashley; Vrable, Abby; Chandrasekaran, Vidya; Beck, Christopher; Hatfield, Kristen R; Herrick, Douglas A; Khoury, Christopher B; Lea, Charlotte; Louie, Christopher A; Lowell, Shannon M; Reynolds, Thomas J; Schibler, Jeanine; Scoma, Alexandra H; Smith-Gee, Maxwell T; Tuberty, Sarah; Smith, Christopher D; Lopilato, Jane E; Hauke, Jeanette; Roecklein-Canfield, Jennifer A; Corrielus, Maureen; Gilman, Hannah; Intriago, Stephanie; Maffa, Amanda; Rauf, Sabya A; Thistle, Katrina; Trieu, Melissa; Winters, Jenifer; Yang, Bib; Hauser, Charles R; Abusheikh, Tariq; Ashrawi, Yara; Benitez, Pedro; Boudreaux, Lauren R; Bourland, Megan; Chavez, Miranda; Cruz, Samantha; Elliott, GiNell; Farek, Jesse R; Flohr, Sarah; Flores, Amanda H; Friedrichs, Chelsey; Fusco, Zach; Goodwin, Zane; Helmreich, Eric; Kiley, John; Knepper, John Mark; Langner, Christine; Martinez, Megan; Mendoza, Carlos; Naik, Monal; Ochoa, Andrea; Ragland, Nicolas; Raimey, England; Rathore, Sunil; Reza, Evangelina; Sadovsky, Griffin; Seydoux, Marie-Isabelle B; Smith, Jonathan E; Unruh, Anna K; Velasquez, Vicente; Wolski, Matthew W; Gosser, Yuying; Govind, Shubha; Clarke-Medley, Nicole; Guadron, Leslie; Lau, Dawn; Lu, Alvin; Mazzeo, Cheryl; Meghdari, Mariam; Ng, Simon; Pamnani, Brad; Plante, Olivia; Shum, Yuki Kwan Wa; Song, Roy; Johnson, Diana E; Abdelnabi, Mai; Archambault, Alexi; Chamma, Norma; Gaur, Shailly; Hammett, Deborah; Kandahari, Adrese; Khayrullina, Guzal; Kumar, Sonali; Lawrence, Samantha; Madden, Nigel; Mandelbaum, Max; Milnthorp, Heather; Mohini, Shiv; Patel, Roshni; Peacock, Sarah J; Perling, Emily; Quintana, Amber; Rahimi, Michael; Ramirez, Kristen; Singhal, Rishi; Weeks, Corinne; Wong, Tiffany; Gillis, Aubree T; Moore, Zachary D; Savell, Christopher D; Watson, Reece; Mel, Stephanie F; Anilkumar, Arjun A; Bilinski, Paul; Castillo, Rostislav; Closser, Michael; Cruz, Nathalia M; Dai, Tiffany; Garbagnati, Giancarlo F; Horton, Lanor S; Kim, Dongyeon; Lau, Joyce H; Liu, James Z; Mach, Sandy D; Phan, Thu A; Ren, Yi; Stapleton, Kenneth E; Strelitz, Jean M; Sunjed, Ray; Stamm, Joyce; Anderson, Morgan C; Bonifield, Bethany Grace; Coomes, Daniel; Dillman, Adam; Durchholz, Elaine J; Fafara-Thompson, Antoinette E; Gross, Meleah J; Gygi, Amber M; Jackson, Lesley E; Johnson, Amy; Kocsisova, Zuzana; Manghelli, Joshua L; McNeil, Kylie; Murillo, Michael; Naylor, Kierstin L; Neely, Jessica; Ogawa, Emmy E; Rich, Ashley; Rogers, Anna; Spencer, J Devin; Stemler, Kristina M; Throm, Allison A; Van Camp, Matt; Weihbrecht, Katie; Wiles, T Aaron; Williams, Mallory A; Williams, Matthew; Zoll, Kyle; Bailey, Cheryl; Zhou, Leming; Balthaser, Darla M; Bashiri, Azita; Bower, Mindy E; Florian, Kayla A; Ghavam, Nazanin; Greiner-Sosanko, Elizabeth S; Karim, Helmet; Mullen, Victor W; Pelchen, Carly E; Yenerall, Paul M; Zhang, Jiayu; Rubin, Michael R; Arias-Mejias, Suzette M; Bermudez-Capo, Armando G; Bernal-Vega, Gabriela V; Colon-Vazquez, Mariela; Flores-Vazquez, Arelys; Gines-Rosario, Mariela; Llavona-Cartagena, Ivan G; Martinez-Rodriguez, Javier O; Ortiz-Fuentes, Lionel; Perez-Colomba, Eliezer O; Perez-Otero, Joseph; Rivera, Elisandra; Rodriguez-Giron, Luke J; Santiago-Sanabria, Arnaldo J; Senquiz-Gonzalez, Andrea M; delValle, Frank R Soto; Vargas-Franco, Dorianmarie; Velázquez-Soto, Karla I; Zambrana-Burgos, Joan D; Martinez-Cruzado, Juan Carlos; Asencio-Zayas, Lillyann; Babilonia-Figueroa, Kevin; Beauchamp-Pérez, Francis D; Belén-Rodríguez, Juliana; Bracero-Quiñones, Luciann; Burgos-Bula, Andrea P; Collado-Méndez, Xavier A; Colón-Cruz, Luis R; Correa-Muller, Ana I; Crooke-Rosado, Jonathan L; Cruz-García, José M; Defendini-Ávila, Marianna; Delgado-Peraza, Francheska M; Feliciano-Cancela, Alex J; Gónzalez-Pérez, Valerie M; Guiblet, Wilfried; Heredia-Negrón, Aldo; Hernández-Muñiz, Jennifer; Irizarry-González, Lourdes N; Laboy-Corales, Ángel L; Llaurador-Caraballo, Gabriela A; Marín-Maldonado, Frances; Marrero-Llerena, Ulises; Martell-Martínez, Héctor A; Martínez-Traverso, Idaliz M; Medina-Ortega, Kiara N; Méndez-Castellanos, Sonya G; Menéndez-Serrano, Krizia C; Morales-Caraballo, Carol I; Ortiz-DeChoudens, Saryleine; Ortiz-Ortiz, Patricia; Pagán-Torres, Hendrick; Pérez-Afanador, Diana; Quintana-Torres, Enid M; Ramírez-Aponte, Edwin G; Riascos-Cuero, Carolina; Rivera-Llovet, Michelle S; Rivera-Pagán, Ingrid T; Rivera-Vicéns, Ramón E; Robles-Juarbe, Fabiola; Rodríguez-Bonilla, Lorraine; Rodríguez-Echevarría, Brian O; Rodríguez-García, Priscila M; Rodríguez-Laboy, Abneris E; Rodríguez-Santiago, Susana; Rojas-Vargas, Michael L; Rubio-Marrero, Eva N; Santiago-Colón, Albeliz; Santiago-Ortiz, Jorge L; Santos-Ramos, Carlos E; Serrano-González, Joseline; Tamayo-Figueroa, Alina M; Tascón-Peñaranda, Edna P; Torres-Castillo, José L; Valentín-Feliciano, Nelson A; Valentín-Feliciano, Yashira M; Vargas-Barreto, Nadyan M; Vélez-Vázquez, Miguel; Vilanova-Vélez, Luis R; Zambrana-Echevarría, Cristina; MacKinnon, Christy; Chung, Hui-Min; Kay, Chris; Pinto, Anthony; Kopp, Olga R; Burkhardt, Joshua; Harward, Chris; Allen, Robert; Bhat, Pavan; Chang, Jimmy Hsiang-Chun; Chen, York; Chesley, Christopher; Cohn, Dara; DuPuis, David; Fasano, Michael; Fazzio, Nicholas; Gavinski, Katherine; Gebreyesus, Heran; Giarla, Thomas; Gostelow, Marcus; Greenstein, Rachel; Gunasinghe, Hashini; Hanson, Casey; Hay, Amanda; He, Tao Jian; Homa, Katie; Howe, Ruth; Howenstein, Jeff; Huang, Henry; Khatri, Aaditya; Kim, Young Lu; Knowles, Olivia; Kong, Sarah; Krock, Rebecca; Kroll, Matt; Kuhn, Julia; Kwong, Matthew; Lee, Brandon; Lee, Ryan; Levine, Kevin; Li, Yedda; Liu, Bo; Liu, Lucy; Liu, Max; Lousararian, Adam; Ma, Jimmy; Mallya, Allyson; Manchee, Charlie; Marcus, Joseph; McDaniel, Stephen; Miller, Michelle L; Molleston, Jerome M; Diez, Cristina Montero; Ng, Patrick; Ngai, Natalie; Nguyen, Hien; Nylander, Andrew; Pollack, Jason; Rastogi, Suchita; Reddy, Himabindu; Regenold, Nathaniel; Sarezky, Jon; Schultz, Michael; Shim, Jien; Skorupa, Tara; Smith, Kenneth; Spencer, Sarah J; Srikanth, Priya; Stancu, Gabriel; Stein, Andrew P; Strother, Marshall; Sudmeier, Lisa; Sun, Mengyang; Sundaram, Varun; Tazudeen, Noor; Tseng, Alan; Tzeng, Albert; Venkat, Rohit; Venkataram, Sandeep; Waldman, Leah; Wang, Tracy; Yang, Hao; Yu, Jack Y; Zheng, Yin; Preuss, Mary L; Garcia, Angelica; Juergens, Matt; Morris, Robert W; Nagengast, Alexis A; Azarewicz, Julie; Carr, Thomas J; Chichearo, Nicole; Colgan, Mike; Donegan, Megan; Gardner, Bob; Kolba, Nik; Krumm, Janice L; Lytle, Stacey; MacMillian, Laurell; Miller, Mary; Montgomery, Andrew; Moretti, Alysha; Offenbacker, Brittney; Polen, Mike; Toth, John; Woytanowski, John; Kadlec, Lisa; Crawford, Justin; Spratt, Mary L; Adams, Ashley L; Barnard, Brianna K; Cheramie, Martin N; Eime, Anne M; Golden, Kathryn L; Hawkins, Allyson P; Hill, Jessica E; Kampmeier, Jessica A; Kern, Cody D; Magnuson, Emily E; Miller, Ashley R; Morrow, Cody M; Peairs, Julia C; Pickett, Gentry L; Popelka, Sarah A; Scott, Alexis J; Teepe, Emily J; TerMeer, Katie A; Watchinski, Carmen A; Watson, Lucas A; Weber, Rachel E; Woodard, Kate A; Barnard, Daron C; Appiah, Isaac; Giddens, Michelle M; McNeil, Gerard P; Adebayo, Adeola; Bagaeva, Kate; Chinwong, Justina; Dol, Chrystel; George, Eunice; Haltaufderhyde, Kirk; Haye, Joanna; Kaur, Manpreet; Semon, Max; Serjanov, Dmitri; Toorie, Anika; Wilson, Christopher; Riddle, Nicole C; Buhler, Jeremy; Mardis, Elaine R; Elgin, Sarah C R

    2015-03-04

    The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25-50%) than euchromatic reference regions (3-11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11-27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4-3.6 vs. 8.4-8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu.

  9. Solving the riddle of interglacial temperatures over the last 1.5 million years with a future IPICS "Oldest Ice" ice core

    NASA Astrophysics Data System (ADS)

    Fischer, Hubertus

    2014-05-01

    The sequence of the last 8 glacial cycles is characterized by irregular 100,000 year cycles in temperature and sea level. In contrast, the time period between 1.5-1.2 million years ago is characterized by more regular cycles with an obliquity periodicity of 41,000 years. Based on a deconvolution of deep ocean temperature and ice volume contributions to benthic δ18O (Elderfield et al., Science, 2012), it is suggested that glacial sea level became progressively lower over the last 1.5 Myr, while glacial deep ocean temperatures were very similar. At the same time many interglacials prior to the Mid Brunhes event showed significantly cooler deep ocean temperatures than the Holocene, while at the same time interglacial ice volume remained essentially the same. In contrast, interglacial sea surface temperatures in the tropics changed little (Herbert et al., Science,2010) and proxy reconstructions of atmospheric CO2 using δ11B in planktic foraminifera (Hönisch et al., Science, 2009) suggest that prior to 900,000 yr before present interglacial CO2 levels did not differ substantially from those over the last 450,000 years. Accordingly, the conundrum arises how interglacials can differ in deep ocean temperature without any obvious change in ice volume or greenhouse gas forcing and what caused the change in cyclicity of glacial interglacial cycles over the Mid Pleistocene Transition. Probably the most important contribution to solve this riddle is the recovery of a 1.5 Myr old ice core from Antarctica, which among others would provide an unambiguous, high-resolution record of the greenhouse gas history over this time period. Accordingly, the international ice core community, as represented by the International Partnership for Ice Core Science (IPICS), has identified such an 'Oldest Ice' ice core as one of the most important scientific targets for the future (http://www.pages.unibe.ch/ipics/white-papers). However, finding stratigraphically undisturbed ice, which covers this

  10. E Pluribus Unum: 50 Years of Research, Millions of Viruses, and One Goal—Tailored Acceleration of AAV Evolution

    PubMed Central

    Grimm, Dirk; Zolotukhin, Sergei

    2015-01-01

    Fifty years ago, a Science paper by Atchison et al. reported a newly discovered virus that would soon become known as adeno-associated virus (AAV) and that would subsequently emerge as one of the most versatile and most auspicious vectors for human gene therapy. A large part of its attraction stems from the ease with which the viral capsid can be engineered for particle retargeting to cell types of choice, evasion from neutralizing antibodies or other desirable properties. Particularly powerful and in the focus of the current review are high-throughput methods aimed at expanding the repertoire of AAV vectors by means of directed molecular evolution, such as random mutagenesis, DNA family shuffling, in silico reconstruction of ancestral capsids, or peptide display. Here, unlike the wealth of prior reviews on this topic, we especially emphasize and critically discuss the practical aspects of the different procedures that affect the ultimate outcome, including diversification protocols, combinatorial library complexity, and selection strategies. Our overall aim is to provide general guidance that should help users at any level, from novice to expert, to safely navigate through the rugged space of directed AAV evolution while avoiding the pitfalls that are associated with these challenging but promising technologies. PMID:26388463

  11. Continuous 1.3-million-year record of East African hydroclimate, and implications for patterns of evolution and biodiversity.

    PubMed

    Lyons, Robert P; Scholz, Christopher A; Cohen, Andrew S; King, John W; Brown, Erik T; Ivory, Sarah J; Johnson, Thomas C; Deino, Alan L; Reinthal, Peter N; McGlue, Michael M; Blome, Margaret W

    2015-12-22

    The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level variability derived from drill core data from Lake Malawi, East Africa (9-15° S). Over the Quaternary, we observe dramatic shifts in effective moisture, resulting in large-scale changes in one of the world's largest lakes and most diverse freshwater ecosystems. Results show evidence for 24 lake level drops of more than 200 m during the Late Quaternary, including 15 lowstands when water levels were more than 400 m lower than modern. A dramatic shift is observed at the Mid-Pleistocene Transition (MPT), consistent with far-field climate forcing, which separates vastly different hydroclimate regimes before and after ∼800,000 years ago. Before 800 ka, lake levels were lower, indicating a climate drier than today, and water levels changed frequently. Following the MPT high-amplitude lake level variations dominate the record. From 800 to 100 ka, a deep, often overfilled lake occupied the basin, indicating a wetter climate, but these highstands were interrupted by prolonged intervals of extreme drought. Periods of high lake level are observed during times of high eccentricity. The extreme hydroclimate variability exerted a profound influence on the Lake Malawi endemic cichlid fish species flock; the geographically extensive habitat reconfiguration provided novel ecological opportunities, enabling new populations to differentiate rapidly to distinct species.

  12. Continuous 1.3-million-year record of East African hydroclimate, and implications for patterns of evolution and biodiversity

    PubMed Central

    Lyons, Robert P.; Scholz, Christopher A.; Cohen, Andrew S.; King, John W.; Brown, Erik T.; Ivory, Sarah J.; Johnson, Thomas C.; Deino, Alan L.; Reinthal, Peter N.; McGlue, Michael M.; Blome, Margaret W.

    2015-01-01

    The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level variability derived from drill core data from Lake Malawi, East Africa (9–15° S). Over the Quaternary, we observe dramatic shifts in effective moisture, resulting in large-scale changes in one of the world’s largest lakes and most diverse freshwater ecosystems. Results show evidence for 24 lake level drops of more than 200 m during the Late Quaternary, including 15 lowstands when water levels were more than 400 m lower than modern. A dramatic shift is observed at the Mid-Pleistocene Transition (MPT), consistent with far-field climate forcing, which separates vastly different hydroclimate regimes before and after ∼800,000 years ago. Before 800 ka, lake levels were lower, indicating a climate drier than today, and water levels changed frequently. Following the MPT high-amplitude lake level variations dominate the record. From 800 to 100 ka, a deep, often overfilled lake occupied the basin, indicating a wetter climate, but these highstands were interrupted by prolonged intervals of extreme drought. Periods of high lake level are observed during times of high eccentricity. The extreme hydroclimate variability exerted a profound influence on the Lake Malawi endemic cichlid fish species flock; the geographically extensive habitat reconfiguration provided novel ecological opportunities, enabling new populations to differentiate rapidly to distinct species. PMID:26644580

  13. Continuous 1.3-million-year record of East African hydroclimate, and implications for patterns of evolution and biodiversity

    NASA Astrophysics Data System (ADS)

    Lyons, Robert P.; Scholz, Christopher A.; Cohen, Andrew S.; King, John W.; Brown, Erik T.; Ivory, Sarah J.; Johnson, Thomas C.; Deino, Alan L.; Reinthal, Peter N.; McGlue, Michael M.; Blome, Margaret W.

    2015-12-01

    The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level variability derived from drill core data from Lake Malawi, East Africa (9-15° S). Over the Quaternary, we observe dramatic shifts in effective moisture, resulting in large-scale changes in one of the world's largest lakes and most diverse freshwater ecosystems. Results show evidence for 24 lake level drops of more than 200 m during the Late Quaternary, including 15 lowstands when water levels were more than 400 m lower than modern. A dramatic shift is observed at the Mid-Pleistocene Transition (MPT), consistent with far-field climate forcing, which separates vastly different hydroclimate regimes before and after ∼800,000 years ago. Before 800 ka, lake levels were lower, indicating a climate drier than today, and water levels changed frequently. Following the MPT high-amplitude lake level variations dominate the record. From 800 to 100 ka, a deep, often overfilled lake occupied the basin, indicating a wetter climate, but these highstands were interrupted by prolonged intervals of extreme drought. Periods of high lake level are observed during times of high eccentricity. The extreme hydroclimate variability exerted a profound influence on the Lake Malawi endemic cichlid fish species flock; the geographically extensive habitat reconfiguration provided novel ecological opportunities, enabling new populations to differentiate rapidly to distinct species.

  14. The Unknown Oldowan: ~1.7-Million-Year-Old Standardized Obsidian Small Tools from Garba IV, Melka Kunture, Ethiopia.

    PubMed

    Gallotti, Rosalia; Mussi, Margherita

    2015-01-01

    The Oldowan Industrial Complex has long been thought to have been static, with limited internal variability, embracing techno-complexes essentially focused on small-to-medium flake production. The flakes were rarely modified by retouch to produce small tools, which do not show any standardized pattern. Usually, the manufacture of small standardized tools has been interpreted as a more complex behavior emerging with the Acheulean technology. Here we report on the ~1.7 Ma Oldowan assemblages from Garba IVE-F at Melka Kunture in the Ethiopian highland. This industry is structured by technical criteria shared by the other East African Oldowan assemblages. However, there is also evidence of a specific technical process never recorded before, i.e. the systematic production of standardized small pointed tools strictly linked to the obsidian exploitation. Standardization and raw material selection in the manufacture of small tools disappear at Melka Kunture during the Lower Pleistocene Acheulean. This proves that 1) the emergence of a certain degree of standardization in tool-kits does not reflect in itself a major step in cultural evolution; and that 2) the Oldowan knappers, when driven by functional needs and supported by a highly suitable raw material, were occasionally able to develop specific technical solutions. The small tool production at ~1.7 Ma, at a time when the Acheulean was already emerging elsewhere in East Africa, adds to the growing amount of evidence of Oldowan techno-economic variability and flexibility, further challenging the view that early stone knapping was static over hundreds of thousands of years.

  15. The Unknown Oldowan: ~1.7-Million-Year-Old Standardized Obsidian Small Tools from Garba IV, Melka Kunture, Ethiopia

    PubMed Central

    2015-01-01

    The Oldowan Industrial Complex has long been thought to have been static, with limited internal variability, embracing techno-complexes essentially focused on small-to-medium flake production. The flakes were rarely modified by retouch to produce small tools, which do not show any standardized pattern. Usually, the manufacture of small standardized tools has been interpreted as a more complex behavior emerging with the Acheulean technology. Here we report on the ~1.7 Ma Oldowan assemblages from Garba IVE-F at Melka Kunture in the Ethiopian highland. This industry is structured by technical criteria shared by the other East African Oldowan assemblages. However, there is also evidence of a specific technical process never recorded before, i.e. the systematic production of standardized small pointed tools strictly linked to the obsidian exploitation. Standardization and raw material selection in the manufacture of small tools disappear at Melka Kunture during the Lower Pleistocene Acheulean. This proves that 1) the emergence of a certain degree of standardization in tool-kits does not reflect in itself a major step in cultural evolution; and that 2) the Oldowan knappers, when driven by functional needs and supported by a highly suitable raw material, were occasionally able to develop specific technical solutions. The small tool production at ~1.7 Ma, at a time when the Acheulean was already emerging elsewhere in East Africa, adds to the growing amount of evidence of Oldowan techno-economic variability and flexibility, further challenging the view that early stone knapping was static over hundreds of thousands of years. PMID:26690569

  16. Rational Action Selection in 1 1/2- to 3-Year-Olds Following an Extended Training Experience

    ERIC Educational Resources Information Center

    Klossek, Ulrike M. H.; Dickinson, Anthony

    2012-01-01

    Previous studies failed to find evidence for rational action selection in children under 2 years of age. The current study investigated whether younger children required more training to encode the relevant causal relationships. Children between 1 1/2 and 3 years of age were trained over two sessions to perform actions on a touch-sensitive screen…

  17. Vegetation and climate development on the North American Atlantic Coastal Plain from 33 to 13 million years ago (IODP Expedition 313)

    NASA Astrophysics Data System (ADS)

    Kotthoff, U.; Greenwood, D. R.; McCarthy, F. M. G.; Müller-Navarra, K.; Hesselbo, S. P.

    2013-12-01

    We have investigated the palynology of sediment cores from Sites M0027 and M0029 of IODP Expedition 313 on the New Jersey shallow shelf, east coast of North America, spanning an age range of 33 to 13 million years before present. Additionally, a pollen assemblage from the Pleistocene was examined. The palynological results were statistically analyzed and complemented with pollen-based quantitative climate reconstructions. Transport-related bias of the pollen assemblages was identified via analysis of the ratio of terrestrial to marine palynomorphs, and considered when interpreting palaeovegetation and palaeoclimate from the pollen data. Results indicate that from the early Oligocene to the middle Miocene, the hinterland vegetation of the New Jersey shelf was characterized by oak-hickory forests in the lowlands and conifer-dominated vegetation in the highlands. The Oligocene witnessed several expansions of conifer forest, probably related to cooling events. The pollen-based climate data imply an increase in annual temperatures from ~12 °C to more than 15 °C during the Oligocene. The Mi-1 cooling event at the onset of the Miocene is reflected by an expansion of conifers and an annual temperature decrease by almost 3 °C, from 15 °C to 12.5 °C around 23 million years before present. Particularly low annual temperatures are also recorded for an interval around ~20 million years before present, which probably reflects the Mi-1aa cooling event. Generally, the Miocene ecosystem and climate conditions were very similar to those of the Oligocene in the hinterland of the New Jersey shelf. Miocene grasslands, as known from other areas in the USA during that time period, are not evident for the hinterland of the New Jersey shelf. Surprisingly, the palaeovegetation data for the hinterland of the New Jersey shelf do not show extraordinary changes during the Mid-Miocene climatic optimum at ~15 million years before present, except for a minor increase in deciduous

  18. Technical/commercial feasibility study of the production of fuel-grade ethanol from corn: 100-million-gallon-per-year production facility in Myrtle Grove, Louisiana

    NASA Astrophysics Data System (ADS)

    1982-05-01

    The technical and economic feasibility of producing motor fuel alcohol from corn in a 100 million gallon per year plant to be constructed in Myrtle Grove, Louisiana is evaluated. The evaluation includes a detailed process design using proven technology, a capital cost estimate for the plant, a detailed analysis of the annual operating cost, a market study, a socioeconomic, environmental, health and safety analysis, and a complete financial analysis. Several other considerations for production of ethanol were evaluated including: cogeneration and fuel to be used in firing the boilers; single by-products vs. multiple by-products; and use of boiler flue gas for by-product drying.

  19. Technical/commercial feasibility study of the production of fuel-grade ethanol from corn: 100-million-gallon-per-year production facility in Myrtle Grove, Louisiana

    SciTech Connect

    Not Available

    1982-05-31

    The technical and economic feasibility of producing motor fuel alcohol from corn in a 100 million gallon per year plant to be constructed in Myrtle Grove, Louisiana is evaluated. The evaluation includes a detailed process design using proven technology, a capital cost estimate for the plant, a detailed analysis of the annual operating cost, a market study, a socioeconomic, environmental, health and safety analysis, and a complete financial analysis. Several other considerations for production of ethanol were evaluated including: cogeneration and fuel to be used in firing the boilers; single by-products vs. multiple by-products; and use of boiler flue gas for by-product drying.

  20. Late Eocene to middle Miocene (33 to 13 million years ago) vegetation and climate development on the North American Atlantic Coastal Plain (IODP Expedition 313, Site M0027)

    NASA Astrophysics Data System (ADS)

    Kotthoff, U.; Greenwood, D. R.; McCarthy, F. M. G.; Müller-Navarra, K.; Prader, S.; Hesselbo, S. P.

    2014-08-01

    We investigated the palynology of sediment cores from Site M0027 of IODP (Integrated Ocean Drilling Program) Expedition 313 on the New Jersey shallow shelf to examine vegetation and climate dynamics on the east coast of North America between 33 and 13 million years ago and to assess the impact of over-regional climate events on the region. Palynological results are complemented with pollen-based quantitative climate reconstructions. Our results indicate that the hinterland vegetation of the New Jersey shelf was characterized by oak-hickory forests in the lowlands and conifer-dominated vegetation in the highlands from the early Oligocene to the middle Miocene. The Oligocene witnessed several expansions of conifer forest, probably related to cooling events. The pollen-based climate data imply an increase in annual temperatures from ∼11.5 °C to more than 16 °C during the Oligocene. The Mi-1 cooling event at the onset of the Miocene is reflected by an expansion of conifers and mean annual temperature decrease of ∼4 °C, from ∼16 °C to ∼12 °C around 23 million years before present. Relatively low annual temperatures are also recorded for several samples during an interval around ∼20 million years before present, which may reflect the Mi-1a and the Mi-1aa cooling events. Generally, the Miocene ecosystem and climate conditions were very similar to those of the Oligocene. Miocene grasslands, as known from other areas in the USA during that time period, are not evident for the hinterland of the New Jersey shelf, possibly reflecting moisture from the proto-Gulf Stream. The palaeovegetation data reveal stable conditions during the mid-Miocene climatic optimum at ∼15 million years before present, with only a minor increase in deciduous-evergreen mixed forest taxa and a decrease in swamp forest taxa. Pollen-based annual temperature reconstructions show average annual temperatures of ∼14 °C during the mid-Miocene climatic optimum, ∼2

  1. H2D(+) observations give an age of at least one million years for a cloud core forming Sun-like stars.

    PubMed

    Brünken, Sandra; Sipilä, Olli; Chambers, Edward T; Harju, Jorma; Caselli, Paola; Asvany, Oskar; Honingh, Cornelia E; Kamiński, Tomasz; Menten, Karl M; Stutzki, Jürgen; Schlemmer, Stephan

    2014-12-11

    The age of dense interstellar cloud cores, where stars and planets form, is a crucial parameter in star formation and difficult to measure. Some models predict rapid collapse, whereas others predict timescales of more than one million years (ref. 3). One possible approach to determining the age is through chemical changes as cloud contraction occurs, in particular through indirect measurements of the ratio of the two spin isomers (ortho/para) of molecular hydrogen, H2, which decreases monotonically with age. This has been done for the dense cloud core L183, for which the deuterium fractionation of diazenylium (N2H(+)) was used as a chemical clock to infer that the core has contracted rapidly (on a timescale of less than 700,000 years). Among astronomically observable molecules, the spin isomers of the deuterated trihydrogen cation, ortho-H2D(+) and para-H2D(+), have the most direct chemical connections to H2 (refs 8, 9, 10, 11, 12) and their abundance ratio provides a chemical clock that is sensitive to greater cloud core ages. So far this ratio has not been determined because para-H2D(+) is very difficult to observe. The detection of its rotational ground-state line has only now become possible thanks to accurate measurements of its transition frequency in the laboratory, and recent progress in instrumentation technology. Here we report observations of ortho- and para-H2D(+) emission and absorption, respectively, from the dense cloud core hosting IRAS 16293-2422 A/B, a group of nascent solar-type stars (with ages of less than 100,000 years). Using the ortho/para ratio in conjunction with chemical models, we find that the dense core has been chemically processed for at least one million years. The apparent discrepancy with the earlier N2H(+) work arises because that chemical clock turns off sooner than the H2D(+) clock, but both results imply that star-forming dense cores have ages of about one million years, rather than 100,000 years.

  2. The Sénèze maar (French Massif-Central): Hypothesis regarding a catastrophe occurring about 1.5 million years ago

    NASA Astrophysics Data System (ADS)

    Couthures, Jean

    1989-11-01

    A reconstruction, based on direct observations in the form of borings and paleontological digs, indicates repetitive catastrophes in the palaeo-lake of the Sénèze depression long after formation of the maar. This event is correlated with extensive slumping associated with erosion of the crater rim induced by a critical ring fault. K-Ar dating gives a lower limit of around 2.48 million years for the initial formation, but not the lapse of time between eruption and filling. According to drilling, sedimentology, and palynological analysis, the lake was functional between 2.3 and 1.3 million years ago, i.e., throughout the Tiglian and at the beginning of the Eburonian. The destruction of all animal life could only have been due to asphyxia, but probably resulted from a CO 2 release. All classes of animals, mainly mammals, were affected and subsequently died. They are found in the same levels in several fossiliferous beds, at the top of the lacustrine deposits and also in reworked debris from the crater rim.

  3. Solid Waste Program Fiscal Year 1996 Multi-Year Program Plan WBS 1.2.1, Revision 1

    SciTech Connect

    1995-09-01

    This document contains the Fiscal Year 1996 Multi-Year Program Plan for the Solid Waste Program at the Hanford Reservation in Richland, Washington. The Solid Waste Program treats, stores, and disposes of a wide variety of solid wastes consisting of radioactive, nonradioactive and hazardous material types. Solid waste types are typically classified as transuranic waste, low-level radioactive waste, low-level mixed waste, and non-radioactive hazardous waste. This report describes the mission, goals and program strategies for the Solid Waste Program for fiscal year 1996 and beyond.

  4. Temporal Learning in 4 1/2- and 6-Year-Old Children: Role of Instructions and Prior Knowledge.

    ERIC Educational Resources Information Center

    Droit, Sylvie; And Others

    1990-01-01

    Examined the role of prior temporal knowledge of 4 1/2- and 6-year-olds through the use of high-rate, interval, and minimal instructions in a fixed-interval training schedule. Determined that the subjects' learning depended on their verbal self-control skills. (BC)

  5. Deepwater royalty relief product of 3 1/2 year U.S. political effort

    SciTech Connect

    Davis, R.E.; Neff, S.

    1996-04-01

    Against the backdrop of more than 20 years of increasingly stringent environmental regulation, ever-expanding exploration and development moratoria on the Outer Continental Shelf (OCS), and reductions in producer tax incentives, oil and natural gas exploration companies active in deep waters of the Gulf of Mexico recently won a significant legislative victory. On Nov. 28, 1995, President Clinton signed into law S.395, the Alaska Power Administration Sale Act. Title 3 of S.395 embodies the Outer Continental Shelf Deep Water Royalty Relief Act. This landmark legislation provides substantial incentives for oil and natural gas production in the gulf of Mexico by temporarily eliminating royalties on certain deepwater leases. It is the first direct incentive for oil and gas production enacted at the federal level in many years. This paper reviews the elements used to arrive at this successful legislation including the congressional leadership. It describes debates, cabinet level discussions, and use of parlimentary procedures.

  6. [3 1/2 years experiences with ECCE with tunnel incision].

    PubMed

    Häberle, H; Anders, N; Antoni, H J; Pham, D T; Wollensak, J

    1997-01-01

    Since January 1992 planned extracapsular cataract extraction (ECCE) is performed routinely with the no-stitch technique at our clinic. To minimize surgically induced astigmatism further, modified wound constructions for planned ECCE with on 1.1-mm tunnel width were evaluated. The follow-up time was up to 3 years postoperatively. For 250 eyes wound closure was performed prospectively either sutureless (n = 70), with a single perpendicular suture (n = 100) or cross sutures (n = 40) at the 12 o'clock position or sutureless in the temporal position (n = 40). The complication rate was 4% (filtering bleb, iris prolapse or transient hypotonia). There were no wound ruptures, but once endophthalmitis was observed. Late mean astigmatism after up to 3 years follow-up for vertical incision was 2.05 +/- 1.16 D (1.01 +/- 0.96 D preoperatively) for sutureless wound closure, 1.63 +/- 1.08 D (0.86 +/- 0.95 D) for perpendicular and 1.76 +/- 0.88 D (0.73 +/- 0.55 D) for cross-sutures. A temporal incision resulted in 0.78 +/- 0.52 D (1.0 +/- 0.69 D) of astigmatism and was only performed on eyes with against the rule astigmatism preoperatively. Surgically induced astigmatism was stabilized early. For with the rule astigmatism preoperatively, a 12 o'clock incision with a perpendicular single suture is recommended and for against the rule astigmatism, a temporal incision.

  7. Climatic variability results in the persistence of transience in estimated erosion rates over millennial to million year timescales in glaciated landscapes

    NASA Astrophysics Data System (ADS)

    von Hagke, Christoph; Ganti, Vamsi; Scherler, Dirk; Lamb, Michael P.; Fisher, Woodward; Avouac, Jean-Philippe

    2014-05-01

    Estimating erosion rate through geologic time is fundamental to quantifying landscape evolution and its response to climatic and tectonic forcing. Recent advances in geo-chronological dating techniques, together with the abundance of data worldwide, allows for quantification of erosion rates over diverse timescales (10 ^ 1-10 ^ 9 yrs). Here, using an unprecedented worldwide data compilation, we show that climatic variability introduces a timescale dependent bias (characterized by an inverse power-law trend of erosion rates on timescale of averaging) in estimated erosion rates that may obscure real temporal changes over millennial to million year timescales in glaciated landscapes. In fluvially dominated landscapes, comparison of multi-scale estimates of erosion rates may reveal real trends such as steady-state and slowly relaxing landscapes. Our analysis suggests that a mechanistic understanding of the effect of long-term climatic variability on landscape evolution is needed to detangle real and apparent changes in landscape-scale erosion rates in glaciated landscapes.

  8. Comments on the BLAG model: the carbonate-silicate geochemical cycle and its effect on atmospheric carbon dioxide over the past 100 million years

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.

    1984-01-01

    A self-consistent method of determining initial conditions for the model presented by Berner, Lasaga, and Garrels (1983) (henceforth, the BLAG model) is derived, based on the assumption that the CO2 geochemical cycle was in steady state at t = -100 my (million years). This initialization procedure leads to a dissolved magnesium concentration higher than that calculated by Berner, Lasaga, and Garrels and to a low ratio of dissolved calcium to bicarbonate prior to 60 my ago. The latter prediction conflicts with the geologic record of evaporite deposits, which requires that this ratio remain greater than 0.5. The contradiction is probably caused by oversimplifications in the BLAG model, such as the neglect of the cycles of organic carbon and sulfur.

  9. Comments on the BLAG model - The carbonate-silicate geochemical cycle and its effect on atmospheric carbon dioxide over the past 100 million years

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.

    1984-01-01

    A self-consistent method of determining initial conditions for the model presented by Berner, Lasaga, and Garrels (1983) (henceforth, the BLAG model) is derived, based on the assumption that the CO2 geochemical cycle was in steady state at t = -100 m.y. (million years). This initialization procedure leads to a dissolved magnesium concentration higher than that calculated by Berner, Lasaga, and Garrels and to a low ratio of dissolved calcium to bicarbonate prior to 60 m.y. ago. The latter prediction conflicts with the geologic record of evaporite deposits, which requires that this ratio remain greater than 0.5. The contradiction is probably caused by oversimplifications in the BLAG model, such as the neglect of the cycles of organic carbon and sulfur.

  10. The "Golden Shale": An indicator of coastal stability for Marble Point, McMurdo Sound, over the last four million years

    USGS Publications Warehouse

    Claridge, G.G.C.; Campbell, I.B.

    2007-01-01

    A small sedimentary deposit near Gneiss Point on the western side of McMurdo Sound, previously identified as shale, is described. The deposit is phillipsite, a zeolite that is believed to have formed from the deposition and alteration of volcanic ash in a small ice-marginal saline lake. Other previously recorded occurrences of phillipsite in the dry valleys are believed to be several million years old. A similar age for this deposit is suggested for the Gneiss Point deposit. This is consistent with other weathering and landscape features found in the immediate area, including traces of halloysite in soils. The deposit is very close to sea level but could not have formed if the site had been below sea level, indicating that there has been very little uplift following that which caused the sea to retreat from the Wright Fiord.

  11. Earliest modern human-like hand bone from a new >1.84-million-year-old site at Olduvai in Tanzania.

    PubMed

    Domínguez-Rodrigo, Manuel; Pickering, Travis Rayne; Almécija, Sergio; Heaton, Jason L; Baquedano, Enrique; Mabulla, Audax; Uribelarrea, David

    2015-08-18

    Modern humans are characterized by specialized hand morphology that is associated with advanced manipulative skills. Thus, there is important debate in paleoanthropology about the possible cause-effect relationship of this modern human-like (MHL) hand anatomy, its associated grips and the invention and use of stone tools by early hominins. Here we describe and analyse Olduvai Hominin (OH) 86, a manual proximal phalanx from the recently discovered >1.84-million-year-old (Ma) Philip Tobias Korongo (PTK) site at Olduvai Gorge (Tanzania). OH 86 represents the earliest MHL hand bone in the fossil record, of a size and shape that differs not only from all australopiths, but also from the phalangeal bones of the penecontemporaneous and geographically proximate OH 7 partial hand skeleton (part of the Homo habilis holotype). The discovery of OH 86 suggests that a hominin with a more MHL postcranium co-existed with Paranthropus boisei and Homo habilis at Olduvai during Bed I times.

  12. Changing climate in a pre-impact world: a multi-proxy paleotemperature reconstruction across the last million years of the Cretaceous

    NASA Astrophysics Data System (ADS)

    Woelders, L.; Vellekoop, J.; Reichart, G. J.; de Nooijer, L. J.; Sluijs, A.; Peterse, F.; Claeys, P. F.; Speijer, R. P.

    2015-12-01

    Climate instability during the last million years of the Cretaceous (67-66 Ma) is still poorly documented and not well understood. One of the reasons for this is that in deep time, different proxies are likely to yield different temperatures. This is because the application of calibrations based on present day temperature proxy relationships is affected by source organism evolution, differences in ocean chemistry and non-analogue processes. Only by combining temperature estimates derived from different, independent proxies, the problems with individual proxies can be cancelled out. A quantitative, multi-proxy temperature record from the latest Cretaceous therefore may provide a better insight in climate changes across this time interval. For such a multi-proxy research, sediments are required that yield both well-preserved foraminiferal calcite as well as organic biomarkers. Very few sites are known to provide such sedimentary records, but ODP Leg 174AX Site Bass River (New Jersey Shelf) has proven to be an excellent archive for paleotemperature reconstructions for the Cretaceous and Paleogene. We here present a multi-proxy, quantitative paleotemperature reconstruction of the last million years of the Cretaceous of the Bass River core. Benthic and planktic foraminiferal Mg/Ca and δ18O were determined, as well as the organic geochemical sea surface temperature proxy TEX86. This resulted in a unique coupled surface and bottom water temperature record of the latest Cretaceous. Our data suggest a ~2-6 ˚C bottom water warming and a ~4-6 ˚C surface water warming approximately 300 kyr before the Cretaceous-Paleogene boundary, followed by a cooling trend across the boundary. This warming event appears to coincide with the main phase of the Deccan Traps eruptions and therefore probably represents a global event.

  13. Biogeochemical variability during the past 3.6 million years recorded by FTIR spectroscopy in the sediment record of Lake El'gygytgyn, Far East Russian Arctic

    NASA Astrophysics Data System (ADS)

    Meyer-Jacob, C.; Vogel, H.; Gebhardt, A. C.; Wennrich, V.; Melles, M.; Rosén, P.

    2014-01-01

    A number of studies have shown that Fourier transform infrared spectroscopy (FTIRS) can be applied to quantitatively assess lacustrine sediment constituents. In this study, we developed calibration models based on FTIRS for the quantitative determination of biogenic silica (BSi; n = 420; gradient: 0.9-56.5%), total organic carbon (TOC; n = 309; gradient: 0-2.9%), and total inorganic carbon (TIC; n= 152; gradient: 0-0.4%) in a 318 m-long sediment record with a basal age of 3.6 million years from Lake El'gygytgyn, Far East Russian Arctic. The developed partial least squares (PLS) regression models yield high cross-validated (CV) R2CV = 0.86-0.91 and low root mean square error of cross-validation (RMSECV) (3.1-7.0% of the gradient for the different properties). By applying these models to 6771 samples from the entire sediment record, we obtained detailed insight into bioproductivity variations in Lake El'gygytgyn throughout the middle to late Pliocene and Quaternary. High accumulation rates of BSi indicate a productivity maximum during the middle Pliocene (3.6-3.3 Ma), followed by gradually decreasing rates during the late Pliocene and Quaternary. The average BSi accumulation during the middle Pliocene was ~3 times higher than maximum accumulation rates during the past 1.5 million years. The indicated progressive deterioration of environmental and climatic conditions in the Siberian Arctic starting at ca. 3.3 Ma is consistent with the first occurrence of glacial periods and the finally complete establishment of glacial-interglacial cycles during the Quaternary.

  14. Factor analysis of the WISC-R (Spanish version) at 11 age levels between 6 1/2 and 16 1/2 years.

    PubMed

    Gass, C S; Demsky, Y I; Martin, P C

    1998-01-01

    The Spanish version of the Wechsler Intelligence Scale for Children-Revised (WISC-R, Wechsler, 1974)-the Escala de Inteligencia para Niños-Revision (EIWN-R, Wechsler, 1982)-has a potentially important role in the assessment of Hispanic children. However, little is known regarding its psychometric characteristics. This study used the normative data from the EIWN-R standardization sample (N = 532 Cuban Americans) to examine its factorial composition and general comparability with the WISC-R. Within each of the 11 age groups (ages 6 1/2 to 16 1/2), the correlation matrix of raw scores was subjected to a principal components analysis and varimax rotation. The results supported a 2-factor solution across age groups roughly corresponding with Wechsler's verbal and performance dimensions. The existence of a meaningful third factor, which has empirical support in the WISC-R literature, failed to emerge for the EIWN-R.

  15. The mapping and differentiation of biological and environmental elemental signatures in the fossil remains of a 50 million year old bird

    SciTech Connect

    Egerton, Victoria M.; Wogelius, Roy A.; Norell, Mark A.; Edwards, Nicholas P.; Sellers, William I.; Bergmann, Uwe; Sokaras, Dimosthenis; Alonso-Mori, Roberto; Ignatyev, Konstantin; van Veelen, Arjen; Anné, Jennifer; van Dongen, Bart; Knoll, Fabien; Manning, Phillip L.

    2015-01-22

    The preservation of fossils reflects the interplay of inorganic and organic chemical processes, which should be clearly differentiated to make interpretations about the biology of extinct organisms. A new coliiformes bird (mouse bird) from the ~50 million year old Green River Formation (Wyoming, USA) has here been analysed using synchrotron X-ray fluorescence and environmental scanning electron microscopy with an attached X-ray energy dispersive system (ESEM-EDS). The concentration and distribution of 16 elements (Si, P, S, Cl, K, Ca, Ti, Mg, Fe, Ni, Cu, Zn, As, Br, Ba, Hg) has been mapped for individual points on the sample. S, Cu and Zn map distinctly within visibly preserved feathers and X-ray Absorption Spectroscopy (XAS) shows that S and Cu within the feathers are organically bound in a similar manner to modern feathers. The morphological preservation of the feathers, on both macro- and microscopic scales, is variable throughout the fossil and the differences in the lateral microfacies have resulted in a morphological preservation gradient. This study clearly differentiates endogenous organic remains from those representing exogenous overprinted geochemical precipitates and illustrates the chemical complexity of the overall taphonomic process.

  16. The mapping and differentiation of biological and environmental elemental signatures in the fossil remains of a 50 million year old bird

    DOE PAGES

    Egerton, Victoria M.; Wogelius, Roy A.; Norell, Mark A.; ...

    2015-01-22

    The preservation of fossils reflects the interplay of inorganic and organic chemical processes, which should be clearly differentiated to make interpretations about the biology of extinct organisms. A new coliiformes bird (mouse bird) from the ~50 million year old Green River Formation (Wyoming, USA) has here been analysed using synchrotron X-ray fluorescence and environmental scanning electron microscopy with an attached X-ray energy dispersive system (ESEM-EDS). The concentration and distribution of 16 elements (Si, P, S, Cl, K, Ca, Ti, Mg, Fe, Ni, Cu, Zn, As, Br, Ba, Hg) has been mapped for individual points on the sample. S, Cu andmore » Zn map distinctly within visibly preserved feathers and X-ray Absorption Spectroscopy (XAS) shows that S and Cu within the feathers are organically bound in a similar manner to modern feathers. The morphological preservation of the feathers, on both macro- and microscopic scales, is variable throughout the fossil and the differences in the lateral microfacies have resulted in a morphological preservation gradient. This study clearly differentiates endogenous organic remains from those representing exogenous overprinted geochemical precipitates and illustrates the chemical complexity of the overall taphonomic process.« less

  17. Coeval Ar-40/Ar-39 ages of 65.0 million years ago from Chicxulub crater melt rock and Cretaceous-Tertiary boundary tektites

    NASA Technical Reports Server (NTRS)

    Swisher, Carl C., III; Grajales-Nishimura, Jose M.; Montanari, Alessandro; Margolis, Stanley V.; Claeys, Philippe; Alvarez, Walter; Renne, Paul; Cedillo-Pardo, Esteban; Maurrasse, Florentin J.-M. R.; Curtis, Garniss H.

    1992-01-01

    Ar-40/Ar-39 dating of drill-core samples of a glassy melt rock recovered from beneath a massive impact breccia contained with the 180-kilometer subsurface Chicxulub crater yields well-behaved incremental heating spectra with a mean plateau age of 64.98 +/- 0.05 million years ago (Ma). The glassy melt rock of andesitic composition was obtained from core 9 (1390 to 1393 meters) in the Chicxulub 1 well. The age of the melt rock is virtually indistinguishable from Ar-40/Ar-39 ages obtained on tektite glass from Beloc, Haiti, and Arroyo el Mimbral, northeastern Mexico, of 65.01 +/- 0.08 Ma (mean plateau age for Beloc) and 65.07 +/- 0.10 Ma (mean total fusion age for both sites). The Ar-40/Ar-39 ages, in conjunction with geochemical and petrological similarities, strengthen the suggestion that the Chicxulub structure is the source for the Haitian and Mexican tektites and is a viable candidate for the Cretaceous-Tertiary boundary impact site.

  18. Lgals6, a 2-Million-Year-Old Gene in Mice: A Case of Positive Darwinian Selection and Presence/Absence Polymorphism

    PubMed Central

    Houzelstein, Denis; Gonçalves, Isabelle R.; Orth, Annie; Bonhomme, François; Netter, Pierre

    2008-01-01

    Duplications of genes are widely considered to be a driving force in the evolutionary process. The fate of such duplicated genes (paralogs) depends mainly on the early stages of their evolution. Therefore, the study of duplications that have already started to diverge is useful to better understand their evolution. We present here the example of a 2-million-year-old segmental duplication at the origin of the Lgals4 and Lgals6 genes in the mouse genome. We analyzed the distribution of these genes in samples from 110 wild individuals and wild-derived inbred strains belonging to eight mouse species from Mus (Coelomys) pahari to M. musculus and 28 laboratory strains. Using a maximum-likelihood method, we show that the sequence of the Lgals6 gene has evolved under the influence of strong positive selection that is likely to result in its neofunctionalization. Surprisingly, despite this selection pressure, the Lgals6 gene is present in some mouse species, but not all. Furthermore, even within the species and populations where it is present, the Lgals6 gene is never fixed. To explain this paradox, we propose different hypotheses such as balanced selection and neutral retention of ancient polymophism and we discuss this unexpected result with regard to known galectin properties and response to infections by pathogens. PMID:18385114

  19. Tiny vampires in ancient seas: evidence for predation via perforation in fossils from the 780-740 million-year-old Chuar Group, Grand Canyon, USA.

    PubMed

    Porter, Susannah M

    2016-05-25

    One explanation for the Early Neoproterozoic expansion of eukaryotes is the appearance of eukaryovorous predators-i.e. protists that preyed on other protists. Evidence for eukaryovory at this time, however, is indirect, based on inferences from character state reconstructions and molecular clocks, and on the presence of possible defensive structures in some protistan fossils. Here I describe 0.1-3.4 µm circular holes in seven species of organic-walled microfossils from the 780-740 million-year-old Chuar Group, Grand Canyon, Arizona, USA, that are similar to those formed today by predatory protists that perforate the walls of their prey to consume the contents inside. Although best known in the vampyrellid amoebae, this 'vampire-like' behaviour is widespread among eukaryotes, making it difficult to infer confidently the identity of the predator. Nonetheless, the identity of the prey is clear: some-and perhaps all-of the fossils are eukaryotes. These holes thus provide the oldest direct evidence for predation on eukaryotes. Larger circular and half-moon-shaped holes in vase-shaped microfossils from the upper part of the unit may also be the work of 'tiny vampires', suggesting a diversity of eukaryovorous predators lived in the ancient Chuar sea.

  20. A 1.3 million year record of synchronous faulting in the hangingwall and border fault of a half-graben in the Malawi (Nyasa) Rift

    NASA Astrophysics Data System (ADS)

    McCartney, Tannis; Scholz, Christopher A.

    2016-10-01

    This paper analyzes throw-depth (T-z) profiles from a high resolution 2D reflection seismic grid in the central basin of Lake Malawi to investigate whether evidence exists: 1) for migration of faulting away from the border fault of the half-graben; and 2) that faults in the hangingwall lengthened over the last 1.3 million years. We use the high-precision age model from a 2005 scientific drilling project in our study area to constrain the ages of our seismic horizons and examine a fault array and two individual faults within the hangingwall of the central basin border fault. We account for climatic and sedimentological controls on stratal growth with a lake-level curve that accompanies the age model. A comparison of our hangingwall T-z profiles with published throw-distance (T-x) profiles for the border fault shows synchronous faulting over the last 1.3 m.y. rather than basinward migration of faulting. Furthermore, we find no evidence for significant propagation of the tips of the hangingwall faults in the last 1.3 m.y. and conclude that the lack of basinward migration of faulting is a consequence of strain localization on faults established at an early stage in basin development.

  1. Re-evolution of lost mandibular teeth in frogs after more than 200 million years, and re-evaluating Dollo's law.

    PubMed

    Wiens, John J

    2011-05-01

    Dollo's law states that structures that are evolutionarily lost will not be regained. Recent phylogenetic studies have revealed several potential examples in which Dollo's law seems to be violated, where lost structures appear to have been regained over evolutionary time. However, these examples have recently been questioned and suggested to be methodological artifacts. In this article, I document a striking and incontrovertible phylogenetic example of the re-evolution of a lost, complex structure: mandibular teeth in the frog genus Gastrotheca. I use a time-calibrated phylogeny for 170 amphibian species to show that mandibular teeth were lost in the ancestor of modern frogs at least 230 million years ago (Mya) and have been regained in the last ∼ 5-17 My. I review recent studies on trait re-evolution and show that this long period of trait absence prior to re-acquisition is largely unprecedented. I also argue that there are several methodological issues that may cause trait re-evolution to be hardest to detect under those conditions when it is most likely to occur, leading to erroneous failures to reject Dollo's law. Finally, I discuss a mechanism that may facilitate trait re-evolution, and the evolution of mandibular teeth in frogs as an example of developmental constraint.

  2. Earliest modern human-like hand bone from a new >1.84-million-year-old site at Olduvai in Tanzania

    PubMed Central

    Domínguez-Rodrigo, Manuel; Pickering, Travis Rayne; Almécija, Sergio; Heaton, Jason L.; Baquedano, Enrique; Mabulla, Audax; Uribelarrea, David

    2015-01-01

    Modern humans are characterized by specialized hand morphology that is associated with advanced manipulative skills. Thus, there is important debate in paleoanthropology about the possible cause–effect relationship of this modern human-like (MHL) hand anatomy, its associated grips and the invention and use of stone tools by early hominins. Here we describe and analyse Olduvai Hominin (OH) 86, a manual proximal phalanx from the recently discovered >1.84-million-year-old (Ma) Philip Tobias Korongo (PTK) site at Olduvai Gorge (Tanzania). OH 86 represents the earliest MHL hand bone in the fossil record, of a size and shape that differs not only from all australopiths, but also from the phalangeal bones of the penecontemporaneous and geographically proximate OH 7 partial hand skeleton (part of the Homo habilis holotype). The discovery of OH 86 suggests that a hominin with a more MHL postcranium co-existed with Paranthropus boisei and Homo habilis at Olduvai during Bed I times. PMID:26285128

  3. Synaptic connections of first-stage visual neurons in the locust Schistocerca gregaria extend evolution of tetrad synapses back 200 million years.

    PubMed

    Wernitznig, Stefan; Rind, Frances Claire; Pölt, Peter; Zankel, Armin; Pritz, Elisabeth; Kolb, Dagmar; Bock, Elisabeth; Leitinger, Gerd

    2015-02-01

    The small size of some insects, and the crystalline regularity of their eyes, have made them ideal for large-scale reconstructions of visual circuits. In phylogenetically recent muscomorph flies, like Drosophila, precisely coordinated output to different motion-processing pathways is delivered by photoreceptors (R cells), targeting four different postsynaptic cells at each synapse (tetrad). Tetrads were linked to the evolution of aerial agility. To reconstruct circuits for vision in the larger brain of a locust, a phylogenetically old, flying insect, we adapted serial block-face scanning electron microscopy (SBEM). Locust lamina monopolar cells, L1 and L2, were the main targets of the R cell pathway, L1 and L2 each fed a different circuit, only L1 providing feedback onto R cells. Unexpectedly, 40% of all locust R cell synapses onto both L1 and L2 were tetrads, revealing the emergence of tetrads in an arthropod group present 200 million years before muscomorph flies appeared, coinciding with the early evolution of flight.

  4. A New 13 Million Year Old Gavialoid Crocodylian from Proto-Amazonian Mega-Wetlands Reveals Parallel Evolutionary Trends in Skull Shape Linked to Longirostry

    PubMed Central

    Salas-Gismondi, Rodolfo; Flynn, John J.; Baby, Patrice; Tejada-Lara, Julia V.; Claude, Julien; Antoine, Pierre-Olivier

    2016-01-01

    Gavialoid crocodylians are the archetypal longirostrine archosaurs and, as such, understanding their patterns of evolution is fundamental to recognizing cranial rearrangements and reconstructing adaptive pathways associated with elongation of the rostrum (longirostry). The living Indian gharial Gavialis gangeticus is the sole survivor of the group, thus providing unique evidence on the distinctive biology of its fossil kin. Yet phylogenetic relationships and evolutionary ecology spanning ~70 million-years of longirostrine crocodylian diversification remain unclear. Analysis of cranial anatomy of a new proto-Amazonian gavialoid, Gryposuchus pachakamue sp. nov., from the Miocene lakes and swamps of the Pebas Mega-Wetland System reveals that acquisition of both widely separated and protruding eyes (telescoped orbits) and riverine ecology within South American and Indian gavialoids is the result of parallel evolution. Phylogenetic and morphometric analyses show that, in association with longirostry, circumorbital bone configuration can evolve rapidly for coping with trends in environmental conditions and may reflect shifts in feeding strategy. Our results support a long-term radiation of the South American forms, with taxa occupying either extreme of the gavialoid morphospace showing preferences for coastal marine versus fluvial environments. The early biogeographic history of South American gavialoids was strongly linked to the northward drainage system connecting proto-Amazonian wetlands to the Caribbean region. PMID:27097031

  5. The Formation of Milky Way-mass Disk Galaxies in the First 500 Million Years of a Cold Dark Matter Universe

    NASA Astrophysics Data System (ADS)

    Feng, Yu; Di Matteo, Tiziana; Croft, Rupert; Tenneti, Ananth; Bird, Simeon; Battaglia, Nicholas; Wilkins, Stephen

    2015-07-01

    Whether or not among the myriad tiny protogalaxies there exists a population with similarities to present-day galaxies is an open question. We show, using BlueTides, the first hydrodynamic simulation large enough to resolve the relevant scales, that the first massive galaxies to form are predicted to have extensive rotationally supported disks. Although their morphology resembles in some ways Milky Way types seen at much lower redshifts, these high-redshift galaxies are smaller, denser, and richer in gas than their low-redshift counterparts. From a kinematic analysis of a statistical sample of 216 galaxies at redshift z = 8-10, we have found that disk galaxies make up 70% of the population of galaxies with stellar mass {10}10{M}⊙ or greater. Cold dark matter cosmology therefore makes specific predictions for the population of large galaxies 500 million years after the Big Bang. We argue that wide-field satellite telescopes (e.g., WFIRST) will in the near future discover these first massive disk galaxies. The simplicity of their structure and formation history should make new tests of cosmology possible.

  6. Lgals6, a 2-million-year-old gene in mice: a case of positive Darwinian selection and presence/absence polymorphism.

    PubMed

    Houzelstein, Denis; Gonçalves, Isabelle R; Orth, Annie; Bonhomme, François; Netter, Pierre

    2008-03-01

    Duplications of genes are widely considered to be a driving force in the evolutionary process. The fate of such duplicated genes (paralogs) depends mainly on the early stages of their evolution. Therefore, the study of duplications that have already started to diverge is useful to better understand their evolution. We present here the example of a 2-million-year-old segmental duplication at the origin of the Lgals4 and Lgals6 genes in the mouse genome. We analyzed the distribution of these genes in samples from 110 wild individuals and wild-derived inbred strains belonging to eight mouse species from Mus (Coelomys) pahari to M. musculus and 28 laboratory strains. Using a maximum-likelihood method, we show that the sequence of the Lgals6 gene has evolved under the influence of strong positive selection that is likely to result in its neofunctionalization. Surprisingly, despite this selection pressure, the Lgals6 gene is present in some mouse species, but not all. Furthermore, even within the species and populations where it is present, the Lgals6 gene is never fixed. To explain this paradox, we propose different hypotheses such as balanced selection and neutral retention of ancient polymophism and we discuss this unexpected result with regard to known galectin properties and response to infections by pathogens.

  7. A New 13 Million Year Old Gavialoid Crocodylian from Proto-Amazonian Mega-Wetlands Reveals Parallel Evolutionary Trends in Skull Shape Linked to Longirostry.

    PubMed

    Salas-Gismondi, Rodolfo; Flynn, John J; Baby, Patrice; Tejada-Lara, Julia V; Claude, Julien; Antoine, Pierre-Olivier

    2016-01-01

    Gavialoid crocodylians are the archetypal longirostrine archosaurs and, as such, understanding their patterns of evolution is fundamental to recognizing cranial rearrangements and reconstructing adaptive pathways associated with elongation of the rostrum (longirostry). The living Indian gharial Gavialis gangeticus is the sole survivor of the group, thus providing unique evidence on the distinctive biology of its fossil kin. Yet phylogenetic relationships and evolutionary ecology spanning ~70 million-years of longirostrine crocodylian diversification remain unclear. Analysis of cranial anatomy of a new proto-Amazonian gavialoid, Gryposuchus pachakamue sp. nov., from the Miocene lakes and swamps of the Pebas Mega-Wetland System reveals that acquisition of both widely separated and protruding eyes (telescoped orbits) and riverine ecology within South American and Indian gavialoids is the result of parallel evolution. Phylogenetic and morphometric analyses show that, in association with longirostry, circumorbital bone configuration can evolve rapidly for coping with trends in environmental conditions and may reflect shifts in feeding strategy. Our results support a long-term radiation of the South American forms, with taxa occupying either extreme of the gavialoid morphospace showing preferences for coastal marine versus fluvial environments. The early biogeographic history of South American gavialoids was strongly linked to the northward drainage system connecting proto-Amazonian wetlands to the Caribbean region.

  8. Diagenesis in limestone-dolostone successions after 1 million years of rapid sea-level fluctuations: A case study from Grand Cayman, British West Indies

    NASA Astrophysics Data System (ADS)

    Ren, Min; Jones, Brian

    2016-08-01

    Meteoric diagenesis in young marine carbonate sediments has commonly been linked to fluctuations in Quaternary glacio-eustatic sea levels. The extent to which these sea-level changes are recorded in these carbonate successions, however, remains questionable. This is amply demonstrated by the diagenetic record found in the limestones and dolostones of the Cayman Formation (Miocene) on the Cayman Islands. On the eastern part of Grand Cayman, dolomitization that ceased by 1 million years ago created an architecture whereby the limestones in the central part of the island were surrounded by dolostones in coastal areas of the island. Since then, the upper 90 m of the Cayman Formation has been repeatedly cycled through many different marine and meteoric diagenetic zones as large, rapid eustatic oscillations in sea level affected the island. The records of these diagenetic cycles in the dolostones and limestones are, however, different and impossible to match to the cyclic changes in sea level. In the peripheral dolostones, post-dolomitization diagenetic features are sparse. In contrast, the limestones in the interior of the island exhibit a wider variety of meteoric diagenetic features, including extensive dissolution and calcite cementation. The dolostones have low porosity (< 10%) and permeability, whereas the limestones are characterized by high porosity (up to 50%), especially in the lower and middle parts of the studied limestone succession. The different phases of diagenesis found in the limestones, however, cannot be specifically matched to any sea-level fluctuations that have affected these successions. This issue is further exemplified by the fact that that the last marine transgression over the last ~ 16,000 years ago appears to have left no tangible record. The analysis of this succession clearly demonstrates that not all diagenetic regimes will be recorded in the fabrics of limestones or dolostones.

  9. Changing socioeconomic inequalities in cancer incidence and mortality: Cohort study with 54 million person-years follow-up 1981-2011.

    PubMed

    Teng, Andrea M; Atkinson, June; Disney, George; Wilson, Nick; Blakely, Tony

    2017-03-15

    Cancer is increasingly responsible for the mortality gap between high and low socioeconomic position groups in high-income countries. This study investigates which cancers are contributing more to socioeconomic gaps in mortality and how this changes over time.New Zealand census data from 1981, 1986, 1991, 1996, 2001 and 2006, were linked to three to five years of subsequent mortality and cancer registrations, resulting in 54 and 42 million years of follow-up cancer incidence and mortality, respectively. Age- and ethnicity-standardised cancer mortality rates and the slope index of inequality (SII) by income were calculated.The contribution of cancer to absolute inequalities (SII) in mortality increased from 16 to 27% for men and from 12 to 31% for women from 1981-84 to 2006-11, peaking in 1991-94 for men and in 1996-99 for women and then levelling off, parallel to peaks in lung cancer inequalities. Lung cancer was the largest driver of cancer inequality trends (49% of the cancer mortality gap in 1981-84 to 33% in 2006-11 for men and 32 to 33% for women) followed by colorectal cancer in men (2 to 11%) and breast cancer in women (declining from 44 to 13%). Women in the lowest income quintile experienced no decline in cancer mortality.The contribution of cancer to income inequalities in all-cause mortality has expanded in this high-income country. Action to address socioeconomic inequalities should prioritise equitable tobacco control, obesity control and improved access to cancer screening, early diagnosis and high quality treatment for those with the lowest incomes.

  10. Hydrothermal versus active margin sediment supply to the eastern equatorial Pacific over the past 23 million years traced by radiogenic Pb isotopes: Paleoceanographic and paleoclimatic implications

    NASA Astrophysics Data System (ADS)

    Höfig, Tobias W.; Hoernle, Kaj; Hauff, Folkmar; Frank, Martin

    2016-10-01

    We investigated the evolution of the Pb isotopic composition of bulk sediments on the Cocos Plate in sedimentary successions of Deep Sea Drilling Project (DSDP) Site 495 and Ocean Drilling Program/Integrated Ocean Drilling Program (ODP/IODP) Site 1256 over the past 23 million years of depositional history. Our study addresses the relationship of the sediment Pb isotope record to plate tectonics, weathering inputs, and paleoceanography. It is the first effort to characterize the Pb isotopic evolution of eastern equatorial Pacific sedimentation covering the entire tectonic pathway of the Cocos Plate from its formation at the East Pacific Rise to its arrival at the Central American subduction zone. The Sites 495 and 1256 bulk sediment Pb isotope records are fully consistent over time despite distinct differences between the type of sediment deposited at both locations. A systematic and continuous trend from ∼23 to ∼6-4 Ma toward more radiogenic Pb isotopic compositions, e.g., 206Pb/204Pb ratios increase from 18.29 to 18.81, reflects a decrease in the contribution of hydrothermal particles from the East Pacific Rise and an increase in the predominantly eolian contribution of mixed weathering products from the continental arcs of the Northern and south Central Andes as well as from southern Mexico. Surprisingly, both the Pb isotopic composition of the detrital fraction and that of past seawater indicate that inputs from nearby Central America and the Galápagos Archipelago did not significantly contribute to the sediments of our core locations but were overwhelmed by other sediment sources. A systematic change to less radiogenic Pb isotope ratios in sediments younger than ∼4-3 Ma, reaching present-day 206Pb/204Pb values near 18.70, reflects a reduction of the continental input from the South Central Volcanic Zone of the Andean Arc and increased contributions from southern Mexican igneous complexes. This isotopic trend reversal took place as a consequence of

  11. Pervasive survival of expressed mitochondrial rps14 pseudogenes in grasses and their relatives for 80 million years following three functional transfers to the nucleus

    PubMed Central

    Ong, Han Chuan; Palmer, Jeffrey D

    2006-01-01

    Background Many mitochondrial genes, especially ribosomal protein genes, have been frequently transferred as functional entities to the nucleus during plant evolution, often by an RNA-mediated process. A notable case of transfer involves the rps14 gene of three grasses (rice, maize, and wheat), which has been relocated to the intron of the nuclear sdh2 gene and which is expressed and targeted to the mitochondrion via alternative splicing and usage of the sdh2 targeting peptide. Although this transfer occurred at least 50 million years ago, i.e., in a common ancestor of these three grasses, it is striking that expressed, nearly intact pseudogenes of rps14 are retained in the mitochondrial genomes of both rice and wheat. To determine how ancient this transfer is, the extent to which mitochondrial rps14 has been retained and is expressed in grasses, and whether other transfers of rps14 have occurred in grasses and their relatives, we investigated the structure, expression, and phylogeny of mitochondrial and nuclear rps14 genes from 32 additional genera of grasses and from 9 other members of the Poales. Results Filter hybridization experiments showed that rps14 sequences are present in the mitochondrial genomes of all examined Poales except for members of the grass subfamily Panicoideae (to which maize belongs). However, PCR amplification and sequencing revealed that the mitochondrial rps14 genes of all examined grasses (Poaceae), Cyperaceae, and Joinvilleaceae are pseudogenes, with all those from the Poaceae sharing two 4-NT frameshift deletions and all those from the Cyperaceae sharing a 5-NT insertion (only one member of the Joinvilleaceae was examined). cDNA analysis showed that all mitochondrial pseudogenes examined (from all three families) are transcribed, that most are RNA edited, and that surprisingly many of the edits are reverse (U→C) edits. Putatively nuclear copies of rps14 were isolated from one to several members of each of these three Poales families

  12. Architecture of thermal adaptation in an Exiguobacterium sibiricum strain isolated from 3 million year old permafrost: A genome and transcriptome approach

    PubMed Central

    Rodrigues, Debora F; Ivanova, Natalia; He, Zhili; Huebner, Marianne; Zhou, Jizhong; Tiedje, James M

    2008-01-01

    Background Many microorganisms have a wide temperature growth range and versatility to tolerate large thermal fluctuations in diverse environments, however not many have been fully explored over their entire growth temperature range through a holistic view of its physiology, genome, and transcriptome. We used Exiguobacterium sibiricum strain 255-15, a psychrotrophic bacterium from 3 million year old Siberian permafrost that grows from -5°C to 39°C to study its thermal adaptation. Results The E. sibiricum genome has one chromosome and two small plasmids with a total of 3,015 protein-encoding genes (CDS), and a GC content of 47.7%. The genome and transcriptome analysis along with the organism's known physiology was used to better understand its thermal adaptation. A total of 27%, 3.2%, and 5.2% of E. sibiricum CDS spotted on the DNA microarray detected differentially expressed genes in cells grown at -2.5°C, 10°C, and 39°C, respectively, when compared to cells grown at 28°C. The hypothetical and unknown genes represented 10.6%, 0.89%, and 2.3% of the CDS differentially expressed when grown at -2.5°C, 10°C, and 39°C versus 28°C, respectively. Conclusion The results show that E. sibiricum is constitutively adapted to cold temperatures stressful to mesophiles since little differential gene expression was observed between 4°C and 28°C, but at the extremities of its Arrhenius growth profile, namely -2.5°C and 39°C, several physiological and metabolic adaptations associated with stress responses were observed. PMID:19019206

  13. Fossil Shorelines Record Multiple Sea Level Highstands and Surface Deformation on Million Year Timescales at Cape Range National Park, Northwestern Australia

    NASA Astrophysics Data System (ADS)

    Sandstrom, R. M.; O'Leary, M.; Barham, M.; Cai, Y.; Jacome, A. P.; Raymo, M. E.

    2015-12-01

    Correcting fossil shorelines for vertical displacement subsequent to deposition is a vital consideration in estimating sea level and ice volume during past warm periods. Field observations of paleo-sea level indicators must be adjusted for local tectonic deformation, subsequent sediment loading, dynamic topography (DT), and glacial isostatic adjustment (GIA). Dynamic topography is often the most difficult of these corrections to determine, especially on million year timescales, but is essential when providing constraints on sea level and ice volume changes. GIA effects from high latitude ice sheets minimally impact northwestern Australia, making this region well suited for observing surface displacement due to mantle and tectonic processes. This study presents centimeter accuracy paleo-shoreline data from four distinct marine terraces in the Cape Range National Park, Australia, which document vertical displacement history along 100 kilometers of coastline. The mapped region has an anticlinal structure in the center that has been slowly uplifting the three older reef complexes over the Neogene, constraining the timing of deformation. These neotectonics are probably caused by reactivation of ancient fault zones normal to the principal horizontal compressive stress, resulting in the warping of overlaying units. The elevation data also suggests minimal vertical displacement since the last interglacial highstand. Well-preserved fossil coral were collected from each terrace and will be geochemically dated using Sr isotope and U-series dating methods. This dataset provides a better understanding of DT and neotectonic deformation in this region (useful for improving mantle viscosity models), and offers a means for improving past sea level reconstructions in northwestern Australia.

  14. Hominin stature, body mass, and walking speed estimates based on 1.5 million-year-old fossil footprints at Ileret, Kenya.

    PubMed

    Dingwall, Heather L; Hatala, Kevin G; Wunderlich, Roshna E; Richmond, Brian G

    2013-06-01

    The early Pleistocene marks a period of major transition in hominin body form, including increases in body mass and stature relative to earlier hominins. However, because complete postcranial fossils with reliable taxonomic attributions are rare, efforts to estimate hominin mass and stature are complicated by the frequent albeit necessary use of isolated, and often fragmentary, skeletal elements. The recent discovery of 1.52 million year old hominin footprints from multiple horizons in Ileret, Kenya, provides new data on the complete foot size of early Pleistocene hominins as well as stride lengths and other characteristics of their gaits. This study reports the results of controlled experiments with habitually unshod Daasanach adults from Ileret to examine the relationships between stride length and speed, and also those between footprint size, body mass, and stature. Based on significant relationships among these variables, we estimate travel speeds ranging between 0.45 m/s and 2.2 m/s from the fossil hominin footprint trails at Ileret. The fossil footprints of seven individuals show evidence of heavy (mean = 50.0 kg; range: 41.5-60.3 kg) and tall individuals (mean = 169.5 cm; range: 152.6-185.8 cm), suggesting that these prints were most likely made by Homo erectus and/or male Paranthropus boisei. The large sizes of these footprints provide strong evidence that hominin body size increased during the early Pleistocene.

  15. Paleoceanography of the eastern equatorial Pacific over the past 4 million years and the geologic origins of modern Galápagos upwelling

    NASA Astrophysics Data System (ADS)

    Karnauskas, Kristopher B.; Mittelstaedt, Eric; Murtugudde, Raghu

    2017-02-01

    An isolated, volcanic archipelago at the confluence of several major ocean currents, the Galápagos Archipelago (GA) is among the most biologically diverse places on Earth. There remain many open questions concerning evolution and speciation in the GA, with the details of the geologic formation of the islands over the past millions of years representing a key source of uncertainty. Paleoceanographic sea surface temperature (SST) proxy records from the far eastern equatorial Pacific (EEP) indicate that the modern gradient of SST across the GA (the cross-island SST gradient, or CIΔT) emerged relatively abruptly ∼1.6 Ma. As the modern CI ΔT is the result of a blockage and subsequent upwelling of the Equatorial Undercurrent (EUC) by the GA, we infer from these paleoceanographic data that the modern period during which the GA is arranged such that the islands constitute a significant topographic barrier to the EUC began ∼1.6 Ma. An extensive suite of ocean circulation model experiments-new and previously published-confirms that the sign and magnitude of the change in CI ΔT captured in paleoceanographic records can be explained by the islands impinging upon the EUC. Implications for the geologic history of the Galápagos and related biogeographical questions are discussed. Additionally, these results suggest that investigations of the Pan-Pacific SST gradient (PPΔT) should use one of the available proxy sites in the EEP that is not influenced by regional, geologically forced oceanographic changes; such an analysis supports recent suggestions of a more gradual development of the modern PP ΔT over the Plio-Pleistocene.

  16. Million Solar Roofs

    SciTech Connect

    2003-11-01

    Since its announcement in June 1997, the Million Solar Roofs Initiative has generated a major buzz in communities, states, and throughout the nation. With more than 300,000 installations, the buzz is getting louder. This brochure describes Million Solar Roofs activities and partnerships.

  17. Quantitative sensory tests before and 1(1/2) years after orthognathic surgery: a cross-sectional study.

    PubMed

    Baad-Hansen, L; Arima, T; Arendt-Nielsen, L; Neumann-Jensen, B; Svensson, P

    2010-05-01

    Quality control is very important in relation to invasive and lengthy treatments, such as integrated orthodontic and surgical correction of dentofacial deformities. The aim of this cross-sectional study was to compare self-reported somatosensory disturbances and quantitative sensory testing (QST) findings between two groups of patients and a healthy control group (n = 24); one group (n = 21) scheduled for bimaxillary orthognathic surgery (BOS) (pre-op) and one group (n = 24) examined 1(1/2) years after BOS (post-op). Self-reported data on pain and somatosensory disturbances were collected, and QST was performed at six trigeminal and one extratrigeminal site. Sensitivity to brush stroke, tactile stimuli, pinprick, two-point-discrimination threshold (2P-DT), pinch pain threshold (PiPT) and pressure pain threshold (PPT) was evaluated. Results were analysed with anovas, Spearman's Correlation, and chi square tests. Eight per cent of post-op patients reported intra-oral, 46% extra-oral, and 46% no somatosensory disturbances. Sensitivity to brush stroke, pinprick and 2P-DT was significantly increased at all examination sites in the post-op patients compared with healthy controls (P < 0.002). Tactile thresholds and PPT did not differ between groups (P > 0.071). Pinch pain threshold were decreased in pre-op patients compared with controls (P < 0.040). Self-reported somatosensory disturbances were not correlated with QST findings. In conclusion; 1(1/2) years after BOS, a large proportion of patients reported somatosensory disturbances and was hypersensitive to mechanical stimuli when compared with pre-op patients and healthy controls. Pre-op patients showed minor somatosensory changes. In addition to patients serving as their own control in prospective studies, a healthy control group and extratrigeminal control sites should be included in future studies.

  18. $425 million for space station

    NASA Astrophysics Data System (ADS)

    Maggs, William Ward

    The Space Station will funded at only about half of the $767 million requested in the 1988 budget for the National Aeronautics and Space Administration (NASA), and overall the agency will receive $8,856 billion for the current fiscal year (FY) in the deficit-reduction package passed by Congress in late December. Despite an earlier complaint that reductions in the space station budget would kill the program and an apparent lack of support from the White House, NASA's official reaction was full of good cheer.NASA will be able to use the $425 million in two installments, $200 million now and $225 million in June. In October, NASA administrator James Fletcher stated in a letter to Senator Jake Garn (R-Utah) that if the space station received no more than $440 million, he would “recommend termination” of the program. But after the budget was approved, NASA said that the $425 million “reflected the strong commitment of the President and the Congress to proceed with the development of a space station.” A recent request to President Reagan from congressional proponents of the station for a letter of support for the multibillion dollar project was declined.

  19. Crystal reaming during the assembly, maturation, and waning of an eleven-million-year crustal magma cycle: thermobarometry of the Aucanquilcha Volcanic Cluster

    NASA Astrophysics Data System (ADS)

    Walker, Barry A.; Klemetti, Erik W.; Grunder, Anita L.; Dilles, John H.; Tepley, Frank J.; Giles, Denise

    2013-04-01

    Phenocryst assemblages of lavas from the long-lived Aucanquilcha Volcanic Cluster (AVC) have been probed to assess pressure and temperature conditions of pre-eruptive arc magmas. Andesite to dacite lavas of the AVC erupted throughout an 11-million-year, arc magmatic cycle in the central Andes in northern Chile. Phases targeted for thermobarometry include amphibole, plagioclase, pyroxenes, and Fe-Ti oxides. Overall, crystallization is documented over 1-7.5 kbar (~25 km) of pressure and ~680-1,110 °C of temperature. Pressure estimates range from ~1 to 5 kbar for amphiboles and from ~3 to 7.5 kbar for pyroxenes. Pyroxene temperatures are tightly clustered from ~1,000-1,100 °C, Fe-Ti oxide temperatures range from ~750-1,000 °C, and amphibole temperatures range from ~780-1,050 °C. Although slightly higher, these temperatures correspond well with previously published zircon temperatures ranging from ~670-900 °C. Two different Fe-Ti oxide thermometers (Andersen and Lindsley 1985; Ghiorso and Evans 2008) are compared and agree well. We also compare amphibole and amphibole-plagioclase thermobarometers (Ridolfi et al. 2010; Holland and Blundy 1994; Anderson and Smith 1995), the solutions from which do not agree well. In samples where we employ multiple thermometers, pyroxene temperature estimates are always highest, zircon temperature estimates are lowest, and Fe-Ti oxide and amphibole temperature estimates fall in between. Maximum Fe-Ti oxide and zircon temperatures are observed during the middle stage of AVC activity (~5-3 Ma), a time associated with increased eruption rates. Amphibole temperatures during this time are relatively restricted (~850-1,000 °C). The crystal record presented here offers a time-transgressive view of an evolving, multi-tiered subvolcanic reservoir. Some crystals in AVC lavas are likely to be true phenocrysts, but the diversity of crystallization temperatures and pressures recorded by phases in individual AVC lavas suggests erupting magma

  20. Uranium-series disequilibrium in tuffs from Yucca Mountain, Nevada, as evidence of pore-fluid flow over the last million years

    USGS Publications Warehouse

    Gascoyne, M.; Miller, N.H.; Neymark, L.A.

    2002-01-01

    Samples of tuff from boreholes drilled into fault zones in the Exploratory Studies Facility (ESF) and relatively unfractured rock of the Cross Drift tunnels, at Yucca Mountain, Nevada, have been analysed by U-series methods. This work is part of a project to verify the finding of fast flow-paths through the tuff to ESF level, indicated by the presence of 'bomb' 36Cl in pore fluids. Secular radioactive equilibrium in the U decay series, (i.e. when the radioactivity ratios 234U/238U, 230Th/234U and 226Ra/230Th all equal 1.00) might be expected if the tuff samples have not experienced radionuclide loss due to rock-water interaction occurring within the last million years. However, most fractured and unfractured samples were found to have a small deficiency of 234U (weighted mean 234U/238U=0.95??0.01) and a small excess of 230Th (weighted mean 230Th/234U 1.10??0.02). The 226Ra/230Th ratios are close to secular equilibrium (weighted mean = 0.94??0.07). These data indicate that 234U has been removed from the rock samples in the last ???350 ka, probably by pore fluids. Within the precision of the measurement, it would appear that 226Ra has not been mobilized and removed from the tuff, although there may be some localised 226Ra redistribution as suggested by a few ratio values that are significantly different from 1.0. Because both fractured and unfractured tuffs show approximately the same deficiency of 234U, this indicates that pore fluids are moving equally through fractured and unfractured rock, More importantly, fractured rock appears not to be a dominant pathway for groundwater flow (otherwise the ratio would be more strongly affected and the Th and Ra isotopic ratios would likely also show disequilibrium). Application of a simple mass-balance model suggests that surface infiltration rate is over an order of magnitude greater than the rate indicated by other infiltration models and that residence time of pore fluids at ESF level is about 400 a. Processes of U

  1. A young Moon-forming giant impact at 70-110 million years accompanied by late-stage mixing, core formation and degassing of the Earth.

    PubMed

    Halliday, Alex N

    2008-11-28

    New W isotope data for lunar metals demonstrate that the Moon formed late in isotopic equilibrium with the bulk silicate Earth (BSE). On this basis, lunar Sr isotope data are used to define the former composition of the Earth and hence the Rb-Sr age of the Moon, which is 4.48+/-0.02Ga, or 70-110Ma (million years) after the start of the Solar System. This age is significantly later than had been deduced from W isotopes based on model assumptions or isotopic effects now known to be cosmogenic. The Sr age is in excellent agreement with earlier estimates based on the time of lunar Pb loss and the age of the early lunar crust (4.46+/-0.04Ga). Similar ages for the BSE are recorded by xenon and lead-lead, providing evidence of catastrophic terrestrial degassing, atmospheric blow-off and significant late core formation accompanying the ca 100Ma giant impact. Agreement between the age of the Moon based on the Earth's Rb/Sr and the lead-lead age of the Moon is consistent with no major losses of moderately volatile elements from the Earth during the giant impact. The W isotopic composition of the BSE can be explained by end member models of (i) gradual accretion with a mean life of roughly 35Ma or (ii) rapid growth with a mean life of roughly 10Ma, followed by a significant hiatus prior to the giant impact. The former assumes that approximately 60 per cent of the incoming metal from impactors is added directly to the core during accretion. The latter includes complete mixing of all the impactor material into the BSE during accretion. The identical W isotopic composition of the Moon and the BSE limits the amount of material that can be added as a late veneer to the Earth after the giant impact to less than 0.3+/-0.3 per cent of ordinary chondrite or less than 0.5+/-0.6 per cent CI carbonaceous chondrite based on their known W isotopic compositions. Neither of these on their own is sufficient to explain the inventories of both refractory siderophiles such as platinum group

  2. A 4.2 million years record of interglacial paleoclimate from sclerochronological data of Florida carbonate platform (Early Pliocene to recent)

    NASA Astrophysics Data System (ADS)

    Brachert, Thomas C.; Reuter, Markus; Krüger, Stefan; Lohmann, Hans; Petuch, Edward J.; Klaus, James S.

    2014-09-01

    The climate of the Pliocene and early Pleistocene was in a transient mode from generally warmer climates of the early Neogene to the maximum glaciations of the late Quaternary. Increasingly severe coolings occurred episodically in the high latitudes, whereas the low latitudes remained warm. For the last 5 million years (Ma), rather constant sea surface temperatures have been recorded in the Western Atlantic warm pool; however, direct climate data on temperature and humidity from shallow near-shore settings are lacking so far. In this study we present a synthesis of 26 new and 46 (incl. 24 recent) published sclerochronogical stable isotope records (18O/16O, 13C/12C) with a sub-annual resolution from reef corals (z-corals) and mollusks. The fossils were sampled from shallow-water carbonate deposits of the Florida carbonate platform and belong to 12 interglacial time-slices spanning collectively the period from the Early Pliocene to the recent (4.2 to 0 Ma). Although platform carbonates are believed to undergo rapid diagenetic stabilization due to the dissolution of metastable aragonite shells, we show that there is still a wealth of material to be recovered for large-scale systematic geochemical studies. We rule out significant diagenetic modifications of the stable isotope data because measured 18O/16O ratios from z-corals and mollusks converted into temperature give consistent results. Accordingly, annual mean temperatures have risen during the last 4.2 Ma from ~ 23 °C to 26 °C in open waters, given the modern seawater value of 18O/16O is valid for Neogene. However, the global water value has changed due to long-term increases in ice volume even during interglacials, equivalent with a 2.3 °C temperature rise. A net 5.3 °C temperature increase over the last 4.2 Ma is inconsistent with the deep-sea record, however, and suggestive of an overall increase of humidity effects in measured 18O/16O instead. Particularly cool temperatures have been registered at 1.9 and

  3. A Million Comet Pieces

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] A Million Comet Pieces (poster version)

    This infrared image from NASA's Spitzer Space Telescope shows the broken Comet 73P/Schwassman-Wachmann 3 skimming along a trail of debris left during its multiple trips around the sun. The flame-like objects are the comet's fragments and their tails, while the dusty comet trail is the line bridging the fragments.

    Comet 73P /Schwassman-Wachmann 3 began to splinter apart in 1995 during one of its voyages around the sweltering sun. Since then, the comet has continued to disintegrate into dozens of fragments, at least 36 of which can be seen here. Astronomers believe the icy comet cracked due the thermal stress from the sun.

    The Spitzer image provides the best look yet at the trail of debris left in the comet's wake after its 1995 breakup. The observatory's infrared eyes were able to see the dusty comet bits and pieces, which are warmed by sunlight and glow at infrared wavelengths. This comet debris ranges in size from pebbles to large boulders. When Earth passes near this rocky trail every year, the comet rubble burns up in our atmosphere, lighting up the sky in meteor showers. In 2022, Earth is expected to cross close to the comet's trail, producing a noticeable meteor shower.

    Astronomers are studying the Spitzer image for clues to the comet's composition and how it fell apart. Like NASA's Deep Impact experiment, in which a probe smashed into comet Tempel 1, the cracked Comet 73P/Schwassman-Wachmann 3 provides a perfect laboratory for studying the pristine interior of a comet.

    This image was taken from May 4 to May 6 by Spitzer's multi-band imaging photometer, using its 24-micron wavelength channel.

  4. Draft Genome Sequence of Staphylococcus succinus subsp. succinus Type Strain DSM 14617, Isolated from Plant and Soil Inclusions within 25- to 35-Million-Year-Old Dominican Amber

    PubMed Central

    Zhou, Hairui; Yao, Zhenyu; Shi, Haihong; Wang, Baixin; Li, Dong; Hou, Jie

    2017-01-01

    ABSTRACT Staphylococcus succinus subsp. succinus type strain DSM 14617 was isolated from plant and soil inclusions within 25- to 35-million-year-old Dominican amber. The complete genome sequence of strain DSM 14617T includes a genome of 2.88 Mb (32.94% G+C content) without any plasmids. PMID:28126945

  5. Use of iron supplements in children aged 1-2 years with iron deficiency anemia: A cross-sectional study

    PubMed Central

    Sezik, Handan Atsiz; Can, Huseyin; Kurnaz, Mehmet Ali; Tuna, Mine; Ay, Zeynep

    2015-01-01

    Objectives: Iron deficiency (ID) is the most common nutritional problem in the world and is the most common cause of childhood anemia. In this study, our aim was to find out about the state of usage of iron preparation, which is distributed free of charge by the Ministry of Health, for the infants between 4-12 months in our country, as well as detecting the awareness degree of families those who are informed about iron-deficiency anemia (IDA), prophylaxis of the drug and to determine the drug’s effectiveness. Methods: It was a cross-sectional survey. The laboratory values from the files of the children aged 1-2 those who visited our hospital’s department of pediatrics, between January 2010 to August 2013, were collected. The survey included families who have children diagnosed with IDA. Questions included about families’ sociodemographic characteristics, the state of the usage of the iron drug, how much information received in terms of the side effects- consumption period and dosage. Results: A total of 139 children were enrolled in our study. While 77.7% of the families who participated stated that (n = 108) iron medicine was prescribed other 43.2% of families stated (n = 60) was prescribed and they were informed about iron pills and IDA. 25.9% of families had received information about drug’s side effects, 74.8% of them had information about period of consumption and 77.7% said they were given information about the drug dose. The average duration of use of iron medicine was 6.98±4.52 (min: 1, max: 24) months. It has been noted that; parent’s education level, mother’s occupation, child’s gender, how the child was born and receiving information about how to use the medicine had no effects on usage of the drug in children. Nevertheless, it has been noticed that, when the families were given proper information the drug use increased and the patients compliance with medications also increased. Conclusion: We believe that, due to frequent diagnosis of

  6. Technical/commercial feasibility study of the production of fuel-grade ethanol from corn: 100-million-gallon-per-year production facility in Myrtle Grove, Louisiana. Volume one. Executive summary

    SciTech Connect

    Not Available

    1982-05-31

    This Executive Summary is Volume I of 7 volumes of a detailed feasibility study for a 100 million gallon/year Power Alcohol plant using corn as feedstock to be constructed in the vicinity of Belle Chaise, Louisiana, adjacent to an existing grain elevator complex. The proposed plant will ultimately have the capability to produce 100 million gallons/year of anhydrous alcohol from an estimated 40 million bushels of corn and will be designed so as to allow construction in modules of 25 million gallons each. Alcohol produced at this plant is intended essentially for use as a gasoline octane booster, a motor fuel in gasoline/alcohol blends and as a chemical feedstock. In addition, the plant will produce a number of by-products, each of which has existing commercial markets; namely, 236,400 tons of CO/sub 2/ 237,600 tons of Protein Meal Mixture (40.2% Protein) or 124,000 tons of Gluten Meal (41% Protein), 20,000 tons of yeast, 68,400 tons of Corn Bran, 89,600 tons of Corn Germ Cake and 4,584,000 gallons of Corn Oil (food grade).

  7. Technical/commercial feasibility study of the production of fuel-grade ethanol from corn: 100-million-gallon-per-year production facility in Myrtle Grove, Louisiana. Volume 1: Executive summary

    NASA Astrophysics Data System (ADS)

    1982-05-01

    An executive summary is given of a detailed feasibility study for a 100 million gallon per year power alcohol plant using corn as feedstock. The proposed plant will ultimately have the capability to produce 100 million gallons per year of anhydrous alcohol from an estimated 40 million bushels of corn and will be designed so as to allow construction in modules of 25 million gallons each. Alcohol produced at this plant is intended essentially for use as a gasoline octane booster, a motor fuel in gasoline/alcohol blends and as a chemical feedstock. In addition, the plant will produce a number of by-products, each of which has existing commercial markets; namely, 236,400 tons of CO2, 237,600 tons of protein meal mixture (40.2% protein), or 124,000 tons of gluten meal (41% protein), 20,000 tons of yeast, 68,400 tons of corn bran, 89,600 tons of corn germ cake and 4,584,000 gallons of corn oil (food grade).

  8. Conservation and divergence of gene expression plasticity following c. 140 million years of evolution in lodgepole pine (Pinus contorta) and interior spruce (Picea glauca×Picea engelmannii).

    PubMed

    Yeaman, Sam; Hodgins, Kathryn A; Suren, Haktan; Nurkowski, Kristin A; Rieseberg, Loren H; Holliday, Jason A; Aitken, Sally N

    2014-07-01

    Species respond to environmental stress through a combination of genetic adaptation and phenotypic plasticity, both of which may be important for survival in the face of climatic change. By characterizing the molecular basis of plastic responses and comparing patterns among species, it is possible to identify how such traits evolve. Here, we used de novo transcriptome assembly and RNAseq to explore how patterns of gene expression differ in response to temperature, moisture, and light regime treatments in lodgepole pine (Pinus contorta) and interior spruce (a natural hybrid population of Picea glauca and Picea engelmannii). We found wide evidence for an effect of treatment on expression within each species, with 6413 and 11,658 differentially expressed genes identified in spruce and pine, respectively. Comparing patterns of expression among these species, we found that 74% of all orthologs with differential expression had a pattern that was conserved in both species, despite 140 million yr of evolution. We also found that the specific treatments driving expression patterns differed between genes with conserved versus diverged patterns of expression. We conclude that natural selection has probably played a role in shaping plastic responses to environment in these species.

  9. Major Improvements to the Heliconius melpomene Genome Assembly Used to Confirm 10 Chromosome Fusion Events in 6 Million Years of Butterfly Evolution

    PubMed Central

    Davey, John W.; Chouteau, Mathieu; Barker, Sarah L.; Maroja, Luana; Baxter, Simon W.; Simpson, Fraser; Merrill, Richard M.; Joron, Mathieu; Mallet, James; Dasmahapatra, Kanchon K.; Jiggins, Chris D.

    2016-01-01

    The Heliconius butterflies are a widely studied adaptive radiation of 46 species spread across Central and South America, several of which are known to hybridize in the wild. Here, we present a substantially improved assembly of the Heliconius melpomene genome, developed using novel methods that should be applicable to improving other genome assemblies produced using short read sequencing. First, we whole-genome-sequenced a pedigree to produce a linkage map incorporating 99% of the genome. Second, we incorporated haplotype scaffolds extensively to produce a more complete haploid version of the draft genome. Third, we incorporated ∼20x coverage of Pacific Biosciences sequencing, and scaffolded the haploid genome using an assembly of this long-read sequence. These improvements result in a genome of 795 scaffolds, 275 Mb in length, with an N50 length of 2.1 Mb, an N50 number of 34, and with 99% of the genome placed, and 84% anchored on chromosomes. We use the new genome assembly to confirm that the Heliconius genome underwent 10 chromosome fusions since the split with its sister genus Eueides, over a period of about 6 million yr. PMID:26772750

  10. Project Ice Storm: Prenatal Maternal Stress Affects Cognitive and Linguistic Functioning in 5 1/2-Year-Old Children

    ERIC Educational Resources Information Center

    Laplante, David P.; Brunet, Alain; Schmitz, Norbert; Ciampi, Antonio; King, Suzanne

    2008-01-01

    The study used data from Project Ice Storm to determine the extent to which exposure to prenatal maternal stress due to a natural disaster can explain variance in the intellectual and language performance of offspring at age 5 1/2.

  11. The incidence of fracture of the proximal femur in two million Canadians from 1972 to 1984. Projections for Canada in the year 2006.

    PubMed

    Martin, A D; Silverthorn, K G; Houston, C S; Bernhardson, S; Wajda, A; Roos, L L

    1991-05-01

    Reported increases in the number of fractures of the proximal femur in Europe are greater than can be explained by demographic changes alone. This trend was assessed in Canada by examining hospital discharge records from the provinces of Saskatchewan and Manitoba from 1972 to 1984. The annual number of first fractures of the proximal femur in persons older than 50 years of age increased 59.7% in women and 42.2% in men during this time period. In most of the five-year age groups the percentage of increase in the number of fractures exceeded the percentage of increase in population of that age group. Annual age-specific incidences (by five-year age groups) increased exponentially with age, doubling every six years, and reached a maximum value of 4% in women older than 90 years of age. Annual age-adjusted incidences increased significantly over the study period in men and women. For the whole of Canada in 1987, it is estimated that there were 13,193 first fractures of the proximal femur in women and 4610 in men, and that in the year 2006 these will rise to 22,922 and 7846, respectively. The actual increase will be considerably greater if the age-specific incidences continue to increase as they have from 1972 to 1984. The gradual decline in physical activity, which contributes to bone loss, may be one etiological factor of this trend during the last half century.

  12. After All, Only Millions?

    PubMed Central

    Rosselló-Móra, Ramon

    2016-01-01

    ABSTRACT An update on the census of species of Archaea and Bacteria published recently in mBio (P. D. Schloss, R. A. Girard, T. Martin, J. Edwards, and J. C. Thrash, mBio 7:e00201-16, 2016, http://dx.doi.org/10.1128/mBio.00201-16) showed again that, despite ever-increasing sequencing efforts, the PCR-based retrieval of 16S rRNA genes is approaching saturation. On average, 95% of the genes analyzed today are identical to those present in public databases, with rarefaction analysis indicating that about one-third of the bacterial and archaeal diversity has already been covered. Therefore, despite estimates of up to 1012 microbial species, the option should be considered that the census of Archaea and Bacteria on planet Earth might yield only millions of species after all. PMID:27381294

  13. Carbon isotope variations in surface waters of the Gulf of Mexico on time scales of 10,000, 30,000, 150,000 and 2 million years

    NASA Astrophysics Data System (ADS)

    Williams, Douglas F.

    Detailed carbon isotope records from surface-dwelling planktonic foraminifera appear to represent δ13C variations in the surface ocean mixed layer of the Gulf of Mexico on different time scales. Correlation of late Pleistocene planktonic δ13C records from the Gulf of Mexico, Panama Basin and southeast Indian Ocean suggests that the surface water δ13C record monitors global changes in the carbon cycle, perhaps changes in atmospheric CO2 levels, and not local effects due to variations in productivity or water temperature. Variations in δ13C of 0.5°/oo occur with a frequency of <500 years in the Holocene and may record background variations in atmospheric pCO2. The meltwater effect on the δ13C of surface waters is largest during the most rapid portion of the deglaciation from isotope stage 2 into stage 1 (from approximately 17 to 12.5 kybp). On time scales representing the last 150,000 years, the most prominent negative δ13C excursion begins in late stage 6 and culminates in the earliest part of isotope stage 5e, a time representing the warmest global temperatures and highest sea levels of the last 150 ky B.P. Major changes in the benthic δ13C record may lead those in the planktonic δ13C record by as much as 10,000 years, but more work is needed to fully explore this observation. A small but significant offset of -0.3°/oo occurs at 900 ky B.P. in the δ13C records of the Gulf of Mexico (E67-135) and Caribbean (DSDP Site 502B (Prell, 1982)), in good agreement with the positive 18O stepwise shift observed in globally distributed DSDP records.

  14. Feasibility study report for the Imperial Valley Ethanol Refinery: a 14. 9-million-gallon-per-year ethanol synfuel refinery utilizing geothermal energy

    SciTech Connect

    Not Available

    1981-03-01

    The construction and operation of a 14,980,000 gallon per year fuel ethanol from grain refinery in the Imperial Valley of California is proposed. The Imperial Valley Ethanol Refinery (refinery) will use hot geothermal fluid from geothermal resources at the East Mesa area as the source of process energy. In order to evaluate the economic viability of the proposed Project, exhaustive engineering, cost analysis, and financial studies have been undertaken. This report presents the results of feasibility studies undertaken in geothermal resource, engineering, marketing financing, management, environment, and permits and approvals. The conclusion of these studies is that the Project is economically viable. US Alcohol Fuels is proceeding with its plans to construct and operate the Refinery.

  15. Antiquity of the biological sulphur cycle: evidence from sulphur and carbon isotopes in 2700 million-year-old rocks of the Belingwe Belt, Zimbabwe.

    PubMed Central

    Grassineau, N V; Nisbet, E G; Bickle, M J; Fowler, C M; Lowry, D; Mattey, D P; Abell, P; Martin, A

    2001-01-01

    Sulphur and carbon isotopic analyses on small samples of kerogens and sulphide minerals from biogenic and non-biogenic sediments of the 2.7 x 10(9) years(Ga)-old Belingwe Greenstone Belt (Zimbabwe) imply that a complex biological sulphur cycle was in operation. Sulphur isotopic compositions display a wider range of biological fractionation than hitherto reported from the Archaean. Carbon isotopic values in kerogen record fractionations characteristic of rubisco activity methanogenesis and methylotrophy and possibly anoxygenic photosynthesis. Carbon and sulphur isotopic fractionations have been interpreted in terms of metabolic processes in 2.7 Ga prokaryote mat communities, and indicate the operation of a diverse array of metabolic processes. The results are consistent with models of early molecular evolution derived from ribosomal RNA. PMID:11209879

  16. Antiquity of the biological sulphur cycle: evidence from sulphur and carbon isotopes in 2700 million-year-old rocks of the Belingwe Belt, Zimbabwe.

    PubMed

    Grassineau, N V; Nisbet, E G; Bickle, M J; Fowler, C M; Lowry, D; Mattey, D P; Abell, P; Martin, A

    2001-01-22

    Sulphur and carbon isotopic analyses on small samples of kerogens and sulphide minerals from biogenic and non-biogenic sediments of the 2.7 x 10(9) years(Ga)-old Belingwe Greenstone Belt (Zimbabwe) imply that a complex biological sulphur cycle was in operation. Sulphur isotopic compositions display a wider range of biological fractionation than hitherto reported from the Archaean. Carbon isotopic values in kerogen record fractionations characteristic of rubisco activity methanogenesis and methylotrophy and possibly anoxygenic photosynthesis. Carbon and sulphur isotopic fractionations have been interpreted in terms of metabolic processes in 2.7 Ga prokaryote mat communities, and indicate the operation of a diverse array of metabolic processes. The results are consistent with models of early molecular evolution derived from ribosomal RNA.

  17. County Poverty Concentration and Disparities in Unintentional Injury Deaths: A Fourteen-Year Analysis of 1.6 Million U.S. Fatalities

    PubMed Central

    Karb, Rebecca A.; Subramanian, S. V.; Fleegler, Eric W.

    2016-01-01

    Unintentional injury is the fourth leading cause of death in the United States, and mortality due to injury has risen over the past decade. The social determinants behind these rising trends have not been well documented. This study examines the relationship between county-level poverty and unintentional injury mortality in the United States from 1999–2012. Complete annual compressed mortality and population data for 1999–2012 were obtained from the National Center for Health Statistics and linked with census yearly county poverty measures. The outcomes examined were unintentional injury fatalities, overall and by six specific mechanisms: motor vehicle collisions, falls, accidental discharge of firearms, drowning, exposure to smoke or fire, and unintentional poisoning. Age-adjusted mortality rates and time trends for county poverty categories were calculated, and multivariate negative binomial regression was used to determine changes over time in both the relative risk of living in high poverty concentration areas and the population attributable fraction. Age-adjusted mortality rates for counties with > 20% poverty were 66% higher mortality in 1999 compared with counties with < 5% poverty (45.25 vs. 27.24 per 100,000; 95% CI for rate difference 15.57,20.46), and that gap widened in 2012 to 79% (44.54 vs. 24.93; 95% CI for rate difference 17.13,22.09). The relative risk of living in the highest poverty counties has increased for all injury mechanisms with the exception of accidental discharge of firearms. The population attributable fraction for all unintentional injuries rose from 0.22 (95% CI 0.13,0.30) in 1999 to 0.35 (95% CI 0.22,0.45) in 2012. This is the first study that uses comprehensive mortality data to document the associations between county poverty and injury mortality rates for the entire US population over a 14 year period. This study suggests that injury reduction interventions should focus on areas of high or increasing poverty. PMID:27144919

  18. The Prevalence of Mental Health Problems in Children 1 1/2 Years of Age--The Copenhagen Child Cohort 2000

    ERIC Educational Resources Information Center

    Skovgaard, Anne Mette; Houmann, Tine; Christiansen, Eva; Landorph, Susanne; Jorgensen, Torben; Olsen, E. M.; Heering, K.; Kaas-Nielsen, S.; Samberg, V.; Lichtenberg, A.

    2007-01-01

    Background: The Copenhagen Child Cohort, CCC 2000, was established to investigate developmental psychopathology prospectively from birth in a general population. Methods: A random sample of 211 children from the CCC 2000 was investigated when the children were 1 1/2 years of age. The prevalence and associates of mental health problems and…

  19. Millions of Americans Bombarded by Loud Noises

    MedlinePlus

    ... of the almost 35 million people who shot guns in the last year used hearing protection. And ... never used any protection. Seventy-seven percent of gun-related noise exposure occurred during recreational shooting, the ...

  20. Tobacco Use Costs World 6 Million Lives, $1 Trillion Annually

    MedlinePlus

    ... gov/news/fullstory_162966.html Tobacco Use Costs World 6 Million Lives, $1 Trillion Annually: Report Higher ... 6 million people a year, and costs the world more than $1 trillion a year in health ...

  1. Waste and decontamination services FY 94 Multi-Year Program Plan Phase II WBS No. 1.2.3

    SciTech Connect

    Cruz, E.A.

    1994-05-01

    During the remediation of the Hanford Site large volumes of radioactive and mixed solid waste are expected to be produced, thus creating the need for subsequent decontamination, treatment, storage, and/or waste disposal. The program mission is to manage current and future contaminated solid waste streams in a safe, responsible, cost effective and legally compliant manner. This document presents the strategy and technical requirements, along with key objectives and deliverables for the waste and decontamination services program for fiscal year 1994. Time schedules, cost estimates, and justification for each proposed activity are given in tables and charts.

  2. Million Dollar School Arson

    ERIC Educational Resources Information Center

    Wilson, Harry W.

    1975-01-01

    Arson at a Bellevue, Washington, high school destroyed the learning resource center. Plans are currently underway to install intruder alarms in a number of schools. (Subscription $14.00 yearly, 2639 S. La Cienega Blvd., Los Angeles, CA 90034.) (MLF)

  3. Outer solar system for 200 million years

    SciTech Connect

    Applegate, J.H.; Douglas, M.R.; Gursel, Y.; Sussman, G.J.; Wisdom, J.

    1986-07-01

    A special-purpose computer is used to integrate the orbits of the outer five planets for more than 100 Myr into the future and more than 100 Myr into the past. The strongest features in the Fourier transforms of the orbital elements of the Jovian planets can be identified with the frequencies predicted by linear secular theory. Many of the weaker features in the Fourier spectra are identified as linear combinations of the basic frequencies. Serious differences are noted between the present measurements and the predictions of Bretagnon (1974). The amplitude of the 3.796 Myr period libration of Pluto's longitude of perihelion is modulated with a period of 34 Myr. Very long periods, on the order of 137 Myr, are also seen. The orbit of Pluto is stable for the duration of the integration; the maximum Liapunov characteristic exponent is less than 10 to the -6.8 power/yr. 21 references.

  4. Jasper Seamount: seven million years of volcanism

    USGS Publications Warehouse

    Pringle, M.S.; Staudigel, H.; Gee, J.

    1991-01-01

    Jasper Seamount is a young, mid-sized (690 km3) oceanic intraplate volcano located about 500 km west-southwest of San Diego, California. Reliable 40Ar/39Ar age data were obtained for several milligram-sized samples of 4 to 10 Ma plagioclase by using a defocused laser beam to clean the samples before fusion. Gee and Staudigel suggested that Jasper Seamount consists of a transitional to tholeiitic shield volcano formed by flank transitional series lavas, overlain by flank alkalic series lavas and summit alkalic series lavas. Twenty-nine individual 40Ar/39Ar laser fusion analyses on nine samples confirm the stratigraphy: 10.3-10.0 Ma for the flank transitional series, 8.7-7.5 Ma for the flank alkalic series, and 4.8-4.1 Ma for the summit alkalic series. The alkalinity of the lavas clearly increases with time, and there appear to be 1 to 3 m.y. hiatuses between each series. -from Authors

  5. Palaeontology: the 165-million-year itch.

    PubMed

    Poinar, George O

    2012-04-24

    New flea-like fossils from China provide a rare, tantalizing glimpse of bizarre insects in the Cretaceous and Jurassic. Possibly the oldest flea-like animals known, they provide a challenge to the functional morphologist to infer which animals they may have targeted.

  6. Jasper Seamount: Seven million years of volcanism

    SciTech Connect

    Pringle, M.S. ); Staudigel, H.; Gee, J. )

    1991-04-01

    Jasper Seamount is a young, mid-sized (690 km{sup 3}) oceanic intraplate volcano located about 500 km west-southwest of San Diego, California. Reliable {sup 40}Ar/{sup 39}Ar age data were obtained for several milligram-sized samples of 4 to 10 Ma plagioclase by using a defocused laser beam to clean the samples before fusion. Gee and Staudigel suggested that Jasper Seamount consists of a transitional to tholeiitic shield volcano formed by flank transitional series lavas, overlain by flank alkalic series lavas and summit alkalic series lavas. Twenty-nine individual {sup 40}Ar/{sup 39}Ar laser fusion analyses on nine samples confirm the stratigraphy: 10.3-10.0 Ma for the flank transitonal series, 8.7-7.5 Ma for the flank alkalic series, and 4.8-4.1 Ma for the summit alkalic series. The alkalinity of the lavas clearly increases with time, and there appear to be 1 to 3 m.y. hiatuses between each series. The age data are consistent with the complex magnetic anomaly of Jasper; however the dominant reversed polarity inferred from the anomaly suggests that most of the seamount formed at ca. 11 Ma, prior to the onset of Chron C5N. The duration of volcanism of Jasper Seamount is slightly longer than the duration of volcanism at Hawaiian volcanoes, suggesting that individual age data from seamounts may constrain the age of a seamount only to within about 7 m.y. unless the stage of volcanism can be unambiguously determined. Extrapolating from the results of our study, similar precision in age determinations should be possible on 50 mg of 1 Ma plagioclase from mid-ocean ridge basalt, opening new possibilities in the geochronology of young, low-potassium volcanic rocks.

  7. One Million Children.

    ERIC Educational Resources Information Center

    Commission on Emotional and Learning Disorders in Children, Toronto (Ontario).

    Presented are the results of a national study of Canadian children with emotional and learning disorders, who number 12% of the Canadian population up to 19 years of age, or no less than 1,000,000 children, who need attention, treatment, and care. The category includes children with neurotic or psychotic or behavior disorders, learning…

  8. Ethylene capacity tops 77 million mty

    SciTech Connect

    Rhodes, A.K.; Knott, D.

    1995-04-17

    World ethylene production capacity is 77.8 million metric tons/year (mty). This total represents an increase of more than 6 million mty, or almost 9%, over last year`s survey. The biggest reason for the large change is more information about plants in the CIS. Also responsible for the increase in capacity is the start-up of several large ethylene plants during the past year. The paper discusses construction of ethylene plants, feedstocks, prices, new capacity, price outlook, and problems in Europe`s ethylene market.

  9. [361 million problems].

    PubMed

    Livi Bacci, M

    1990-01-01

    The discipline of demography has come to focus on questions amenable to specific quantifiable answers to the detriment of larger, more significant questions that were uppermost in the minds of the 1st demographers. The question of what determines total population size at a given moment is 1 such larger question. On a scale of centuries or millenia, a curve representing 3 great phases in populaiton growth, in the upper paleolithic, from the neolithic to the industrial revolution, and from the industrial revolution to the present may appear reasonable. But the appearance of orderly progress disapprears when decades or even single years are substituted for millenia. Population growth can be considered the result of opposing forces of constriction and election. The forces of constriction historically were tied to limitations in the natural environment, hostile climates, food shortages, or infectious diseases. Human beings exercised partial control at best over these forces. The demographically relevant forces of election were those affecting processes of family formation, fertility, and occupation of new territories and empty land. The forces of election allowed populations to adapt and react to the forces of constriction, providing the flexibility needed to ensure survival. Flexibility would also come from processes of biological or sociobiological adaptation to the forces of constriction. Technical advances over the past 2 centuries have deluded many into believing that human beings are overcoming the tyranny of constrictive forces and that human demographic behavior can be guided by election. The 20th century has to some extent witnessed greater flexibility of populations in responding to factors of constriction. The gradual diffusion of modern fertility control is a great advance, but on the other hand the regulator of geographic distribution of population through migration is becoming more and more limited. The constrictive factors limiting population growth are

  10. Human-like external function of the foot, and fully upright gait, confirmed in the 3.66 million year old Laetoli hominin footprints by topographic statistics, experimental footprint-formation and computer simulation

    PubMed Central

    Crompton, Robin H.; Pataky, Todd C.; Savage, Russell; D'Août, Kristiaan; Bennett, Matthew R.; Day, Michael H.; Bates, Karl; Morse, Sarita; Sellers, William I.

    2012-01-01

    It is commonly held that the major functional features of the human foot (e.g. a functional longitudinal medial arch, lateral to medial force transfer and hallucal (big-toe) push-off) appear only in the last 2 Myr, but functional interpretations of footbones and footprints of early human ancestors (hominins) prior to 2 million years ago (Mya) remain contradictory. Pixel-wise topographical statistical analysis of Laetoli footprint morphology, compared with results from experimental studies of footprint formation; foot-pressure measurements in bipedalism of humans and non-human great apes; and computer simulation techniques, indicate that most of these functional features were already present, albeit less strongly expressed than in ourselves, in the maker of the Laetoli G-1 footprint trail, 3.66 Mya. This finding provides strong support to those previous studies which have interpreted the G-1 prints as generally modern in aspect. PMID:21775326

  11. Prevalence of species and genotypes of Cryptosporidium found in 1-2-year-old dairy cattle in the eastern United States.

    PubMed

    Fayer, Ronald; Santín, Mónica; Trout, James M; Greiner, Ellis

    2006-01-30

    The prevalence of Cryptosporidium species in 1-2-year-old heifers was determined for 571 animals on 14 dairy farms in seven states on the East Coast of the United States. A fecal specimen collected directly from each heifer was processed to concentrate oocysts that were then examined by polymerase chain reaction (PCR). For every PCR-positive specimen the 18S rRNA gene of Cryptosporidium was sequenced. Cryptosporidium was identified by PCR from heifers on 13 of 14 farms. On all except four farms groups of heifers were housed in a barn or in large covered pens. Others were pastured. From many of the same farms an earlier study reported that 41% of 393 pre-weaned calves and 26.2% of 447 post-weaned calves were infected. In the present study, 11.9% of 571 heifers were infected with Cryptosporidium, 0.7% with Cryptosporidium parvum, the zoonotic species. Of 68 PCR-positive specimens characterized by gene sequencing 1, 4, 10, 24, and 29 calves were infected with Cryptosporidium suis, Cryptosporidium parvum, Cryptosporidium deer-like genotype, Cryptosporidium bovis, and Cryptosporidium andersoni, respectively. These findings demonstrate a lower prevalence of infection in 1-2-year-old dairy cattle than in younger cattle as well as a change in the diversity of species present. Consequently, the risk of humans acquiring infection with C. parvum from exposure to feces from yearling and older cattle appears much lower than from exposure to pre-weaned calves.

  12. Phase 1/2 study of carfilzomib plus melphalan and prednisone in patients aged over 65 years with newly diagnosed multiple myeloma.

    PubMed

    Moreau, Philippe; Kolb, Brigitte; Attal, Michel; Caillot, Denis; Benboubker, Lotfi; Tiab, Mourad; Touzeau, Cyrille; Leleu, Xavier; Roussel, Murielle; Chaleteix, Carine; Planche, Lucie; Chiffoleau, Anne; Fortin, June; Avet-Loiseau, Hervé; Mary, Jean-Yves; Hulin, Cyrille; Facon, Thierry

    2015-05-14

    This phase 1/2 dose-escalation study investigated the combination of carfilzomib with melphalan and prednisone (CMP) in patients aged >65 years with newly diagnosed multiple myeloma (MM). Melphalan and prednisone were administered orally on days 1 to 4; carfilzomib was IV administered on days 1, 2, 8, 9, 22, 23, 29, and 30 of a 42-day cycle. Patients received up to 9 cycles of CMP. In the phase 1 dose-escalation portion, the primary objectives were to determine the incidence of dose-limiting toxicities during the first cycle of CMP treatment to define the maximal tolerated dose (MTD) of carfilzomib. In the phase 2 portion, the primary objective was to evaluate the overall response rate (ORR) of CMP. In the phase 1 portion of the study, 24 patients received CMP at carfilzomib dosing levels of 20 mg/m(2), 27 mg/m(2), 36 mg/m(2), and 45 mg/m(2). The MTD was established as 36 mg/m(2). In the phase 2 portion of the study, 44 patients were enrolled at the MTD. Among 50 efficacy-evaluable patients treated at the MTD, the ORR was 90%. The projected 3-year overall survival rate was 80%. The combination of CMP was observed to be effective in elderly patients with newly diagnosed MM. This trial was registered at www.clinicaltrials.gov as #NCT01279694 (Eudract identifier 2010-019462-92).

  13. Saving Millions without Spending a Dime.

    ERIC Educational Resources Information Center

    Raman, Elizabeth

    2003-01-01

    Describes how the University of Hawaii at Hilo is using the $2.7 million it saved on utility bills during the past 5 years to repay campus energy improvements financed, installed, and maintained by an energy services company; the method is called energy savings performance contracting. (EV)

  14. Mineralogical composition and geographical distribution of African and Brazilian periatlantic laterites. The influence of continental drift and tropical paleoclimates during the past 150 million years and implications for India and Australia

    NASA Astrophysics Data System (ADS)

    Tardy, Y.; Kobilsek, B.; Paquet, H.

    Following the break-up of Pangea at the end of the Jurassic time, the African and South American continents and then India and Australia drifted into the fringes of the equatorial or tropical climatic zone with the humidity varying according to the epochs. India, Brazil and the southern part of East Africa which were previously more arid and probably hotter during the Jurassic, became progressively more humid and cooler. By contrast, West Africa, Central Africa and Australia, formerly subject to very humid climates became subject to warmer and drier climatic conditions. In the first case, the ferricretes were rarely preserved intact but bauxites, generally massive and non pisolitic and essentially formed of gibbsite (Al(OH) 3) are abundant. In the second case, hematite (Fe 2O 3) occurring as nodular ferricretes are extensively developed together with gibbsite-bearing pisolitic bauxites and boehmite (AlOOH). Gibbsite and goethite are hydrated minerals related to humid and rather cool climates, whereas hematite and boehmite are dehydrated minerals related to less humid and warmer climatic conditions. Thus temperature, relative humidity of the atmosphere and the activity of water are the major climatic and thermodynamic parameters controlling the mechanisms of formation, the processes of evolution and the geographical distribution of bauxites and ferricretes. Furthermore, the geographical distribution and the mineralogical composition of ferricretes and bauxites are considered to be controlled not only by the different present-day climates but also and perhaps above all by the succession of paleoclimates during the past 150 million years.

  15. Scoping design analyses for optimized shipping casks containing 1-, 2-, 3-, 5-, 7-, or 10-year-old PWR spent fuel

    SciTech Connect

    Bucholz, J.A.

    1983-01-01

    This report details many of the interrelated considerations involved in optimizing large Pb, Fe, or U-metal spent fuel shipping casks containing 1, 2, 3, 5, 7, or 10-year-old PWR fuel assemblies. Scoping analyses based on criticality, shielding, and heat transfer considerations indicate that some casks may be able to hold as many as 18 to 21 ten-year-old PWR fuel assemblies. In the criticality section, a new type of inherently subcritical fuel assembly separator is described which uses hollow, borated stainless-steel tubes in the wall-forming structure between the assemblies. In another section, details of many n/..gamma.. shielding optimization studies are presented, including the optimal n/..gamma.. design points and the actual shielding requirements for each type of cask as a function of the age of the spent fuel and the number of assemblies in the cask. Multigroup source terms based on ORIGEN2 calculations at these and other decay times are also included. Lastly, the numerical methods and experimental correlations used in the steady-state and transient heat transfer analyses are fully documented, as are pertinent aspects of the SCOPE code for Shipping Cask Optimization and Parametric Evaluation. (While only casks for square, intact PWR fuel assemblies were considered in this study, the SCOPE code may also be used to design and analyze casks containing canistered spent fuel or other waste material. An abbreviated input data guide is included as an appendix).

  16. Four-Year Maintenance Treatment With Adalimumab in Patients with Moderately to Severely Active Ulcerative Colitis: Data from ULTRA 1, 2, and 3

    PubMed Central

    Colombel, Jean-Frederic; Sandborn, William J; Ghosh, Subrata; Wolf, Douglas C; Panaccione, Remo; Feagan, Brian; Reinisch, Walter; Robinson, Anne M; Lazar, Andreas; Kron, Martina; Huang, Bidan; Skup, Martha; Thakkar, Roopal B

    2014-01-01

    OBJECTIVES: The safety and efficacy of adalimumab for patients with moderately to severely active ulcerative colitis (UC) has been reported up to week 52 from the placebo-controlled trials ULTRA (Ulcerative Colitis Long-Term Remission and Maintenance with Adalimumab) 1 and 2. Up to 4 years of data for adalimumab-treated patients from ULTRA 1, 2, and the open-label extension ULTRA 3 are presented. METHODS: Remission per partial Mayo score, remission per Inflammatory Bowel Disease Questionnaire (IBDQ) score, and mucosal healing rates were assessed in adalimumab-randomized patients from ULTRA 1 and 2 up to week 208. Corticosteroid-free remission was assessed in adalimumab-randomized patients who used corticosteroids at lead-in study baseline. Maintenance of remission per partial Mayo score and mucosal healing was assessed in patients who entered ULTRA 3 in remission per full Mayo score and with mucosal healing, respectively. As observed, last observation carried forward (LOCF) and nonresponder imputation (NRI) were used to report efficacy. Adverse events were reported for any adalimumab-treated patient. RESULTS: A total of 600/1,094 patients enrolled in ULTRA 1 or 2 were randomized to receive adalimumab and included in the intent-to-treat analyses of the studies. Of these, 199 patients remained on adalimumab after 4 years of follow-up. Rates of remission per partial Mayo score, remission per IBDQ score, mucosal healing, and corticosteroid discontinuation at week 208 were 24.7%, 26.3%, 27.7% (NRI), and 59.2% (observed), respectively. Of the patients who were followed up in ULTRA 3 (588/1,094), a total of 360 patients remained on adalimumab 3 years later. Remission per partial Mayo score and mucosal healing after ULTRA 1 or 2 to year 3 of ULTRA 3 were maintained by 63.6% and 59.9% of patients, respectively (NRI). Adverse event rates were stable over time. CONCLUSIONS: Remission, mucosal healing, and improved quality of life were maintained in patients with moderately to

  17. Mr Cameron's Three Million Apprenticeships

    ERIC Educational Resources Information Center

    Allen, Martin

    2015-01-01

    In the 2015 general election campaign David Cameron celebrated the success of apprenticeships during the Coalition and promised another 3 million. This article argues that the "reinvention" of apprenticeships has neither created real skills nor provided real alternatives for young people and that the UK schemes fall far short of those in…

  18. Examination of Global Seismic Tomography Images and Sea-Surface Magnetic Field Anomaly Profiles in the West Philippine Basin for the Large Clockwise Rotation of the Philippine Sea Plate during the Last 55 Million Years

    NASA Astrophysics Data System (ADS)

    Choe, H.; Lee, S. M.

    2014-12-01

    The Philippine Sea Plate is thought to have undergone a 90° clockwise rotation during the last 55 million years. However, evidences for such an argument are rather circumstantial. For instance, paleomagnetic measurements for the large rotation are derived largely from Halmahera, Indonesia which is quite close to the plate boundary. It is thus possible that this region may have undergone local deformation separate from the main parts of the Philippine Sea Plate. In this study, we examine the global seismic tomography images of the mantle beneath the Philippine Sea Plate and the marine magnetic field anomaly data at the sea surface from the West Philippine Basin to see whether they agree with the presumed motion of the Philippine Sea Plate. Our comparison between the plate reconstruction and global tomography suggests that the rotation of Philippine Sea Plate may not have been continuous but instead experienced a temporal break at around 32 Ma. The exact nature of this pause is uncertain, but it may be related to a sudden change in the configuration of subduction systems. A detail comparison with recent results from IODP Legs 350 and 351 is therefore necessary, including a search for a change in the depositional style of basin sediment. We also examined the detailed the shape of magnetic anomalies (such as skewness) and compare them with the previous model by allowing the magnetization to have direction corresponding to that during the opening of the West Philippine Basin. At this moment, it is too early to tell if the sudden change at around 32 Ma or other inferred breaks can be seen in the magnetic profiles as well.

  19. Time to remission for eating disorder patients: a 2(1/2)-year follow-up study of outcome and predictors.

    PubMed

    Clausen, Loa

    2008-01-01

    The aim of the present study was to analyse outcome, time to remission, and predictors of time to remission in a cohort of Danish eating disorder patients. Seventy-eight patients (35 anorexic, 30 bulimic and 13 unspecified eating disorder patients) were interviewed 2(1/2) years after initial assessment. Method of assessment was Eating Disorder Examination (EDE), Longitudinal Interval Follow-up Evaluation of Eating Disorders (LIFE-EAT-II), Eating Disorder Inventory (EDI), Symptom Check List (SCL-90R), Present State Examination (PSE) and the Structured Clinical Interview for DSM-III-R Axis-II (SCID-II). Method of analysis was Kaplan-Meier estimate of survival, Log Rank test and Cox regression analysis. In total 48.7% reached remission with mean time to remission at 27 months. A trend difference between the diagnostic groups when measuring time to remission was found, i.e. patients with unspecified eating disorders remitted faster than bulimic (BN) patients who in turn remitted faster than anorexic (AN) patients. Body mass index (BMI) at baseline was the best predictor of time to remission for the total sample. Predictors differed when looking at diagnostic groups separately. Final outcome was comparable with earlier studies while relapse frequency was low. Patients with AN remitted faster than found in earlier survival analysis studies, while the remission rate for BN patients was comparable with earlier studies. Despite the prognostic value of BMI for the total sample, predictor analysis implied more disorder diversity than homogeneity.

  20. 12 Scientists Will Share $120-Million from Saudis

    ERIC Educational Resources Information Center

    Guterman, Lila

    2008-01-01

    This spring 12 scientists found themselves in an unusual position--they have to figure out how to spend $2-million every year for the next five years. The money adds up to $10-million per researcher. In May the researchers made a pilgrimage to the source of the generous grants: King Abdullah University of Science and Technology, a graduate…

  1. White House Budget Proposal Would Provide National Science Foundation With 1.2% Increase

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2014-03-01

    The proposed 7.255 billion budget request for the U.S. National Science Foundation (NSF) for fiscal year (FY) 2015, announced by the White House on 4 March, would increase funding just 83 million, 1.2% above the FY 2014 estimate (see Table 1). The budget for NSF's Directorate for Geosciences (GEO) would nudge up 0.1% to 1.304 billion, an increase of 1.36 million (see Table 2).

  2. Biodiesel Fuel Company Owner Pleads Guilty to Fraud and Clean Air Act Crimes Connected to Renewable Fuels Scheme / Philip J. Rivkin faces more than 10 years imprisonment and $51 million in restitution

    EPA Pesticide Factsheets

    WASHINGTON - Philip Joseph Rivkin, a.k.a. Felipe Poitan Arriaga, 50, today pleaded guilty to a Clean Air Act false statement and mail fraud as part of his role in a scheme to defraud EPA by falsely representing that he was producing millions of gall

  3. Monsanto Gives Washington U. $23.5 Million.

    ERIC Educational Resources Information Center

    Culliton, Barbara J.

    1982-01-01

    Reviews various provisions of a five-year, $23.5-million research agreement between Washington University and the Monsanto Company. The scientific focus of this venture will be on proteins and peptides which modify cellular behavior. (SK)

  4. Predictors (0-10 Months) of Psychopathology at Age 1 1/2 Years--A General Population Study in the Copenhagen Child Cohort CCC 2000

    ERIC Educational Resources Information Center

    Skovgaard, A. M.; Olsen, E. M.; Christiansen, E.; Houmann, T.; Landorph, S. L.; Jorgensen, T.

    2008-01-01

    Background: Epidemiological studies of mental health problems in the first years of life are few. This study aims to investigate infancy predictors of psychopathology in the second year of life. Methods: A random general population sample of 210 children from the Copenhagen Child Birth Cohort CCC 2000 was investigated by data from National Danish…

  5. CDC Allocates $184 Million for Zika Protection

    MedlinePlus

    ... fullstory_162694.html CDC Allocates $184 Million for Zika Protection Funds are earmarked for states, territories, local ... million has been earmarked to protect Americans against Zika virus infection, the U.S. Centers for Disease Control ...

  6. Million Query Track 2007 Overview

    DTIC Science & Technology

    2007-01-01

    Technology, China Used Lemur . IBM Haifa This year, the experiments of IBM Haifa were focused on the scoring function of Lucene, an Apache open-source...several standard Lemur built in systems (tfidf bm25, tfidf log, kl abs,kl dir,inquery,cos, okapi) and combined their output (metasearch) using the

  7. Effect of recombinant human growth hormone on changes in height, bone mineral density, and body composition over 1-2 years in children with Hurler or Hunter syndrome.

    PubMed

    Polgreen, Lynda E; Thomas, William; Orchard, Paul J; Whitley, Chester B; Miller, Bradley S

    2014-02-01

    Patients with Hurler or Hunter syndrome typically have moderate to severe growth deficiencies despite therapy with allogeneic hematopoietic stem cell transplantation and/or enzyme replacement therapy. It is unknown whether treatment with recombinant human growth hormone (hGH) can improve growth in these children. The objectives of this study were to determine the effects of hGH on growth, bone mineral density (BMD), and body composition in children with Hurler or Hunter syndrome enrolled in a longitudinal observational study. The difference in annual change in outcomes between hGH treated and untreated subjects was estimated by longitudinal regression models that adjusted for age, Tanner stage, and sex where appropriate. We report on 23 participants who completed at least 2 annual study visits (10 [43%] treated with hGH): Hurler syndrome (n=13) average age of 9.8 ± 3.1 years (range 5.3-13.6 years; 54% female) and Hunter syndrome (n=10) average age of 12.0 ± 2.7 years (range 7.0-17.0 years; 0% female). As a group, children with Hurler or Hunter syndrome treated with hGH had no difference in annual change in height (growth velocity) compared to those untreated with hGH. Growth velocity in hGH treated individuals ranged from -0.4 to 8.1cm/year and from 0.3 to 6.6 cm/year in the untreated individuals. Among children with Hunter syndrome, 100% (N=4) of those treated but only 50% of those untreated with hGH had an annual increase in height standard deviation score (SDS). Of the individuals treated with hGH, those with GHD had a trend towards higher annualized growth velocity compared to those without GHD (6.5 ± 1.9 cm/year vs. 3.5 ± 2.1cm/year; p=.050). Children treated with hGH had greater annual gains in BMD and lean body mass. In conclusion, although as a group we found no significant difference in growth between individuals treated versus not treated with hGH, individual response was highly variable and we are unable to predict who will respond to treatment. Thus

  8. Fungal associations in Horneophyton ligneri from the Rhynie Chert (c. 407 million year old) closely resemble those in extant lower land plants: novel insights into ancestral plant-fungus symbioses.

    PubMed

    Strullu-Derrien, Christine; Kenrick, Paul; Pressel, Silvia; Duckett, Jeffrey G; Rioult, Jean-Philippe; Strullu, Désiré-Georges

    2014-08-01

    Fungi (Eumycota) form close associations with plants, with which they have co-existed since the dawn of life on land, but their diversity in early terrestrial ecosystems is still poorly understood. We studied petrographic sections of exceptionally well-preserved petrified plants from the 407 million yr-old Rhynie Chert (Scotland, UK). For comparative purposes, we illustrate fungal associations in four extant lower land plants. We document two new endophytes in the plant Horneophyton lignieri: Palaeoglomus boullardii (sp. nov. Glomeromycota) colonizes parenchyma in a discontinuous zone of the outer cortex of the aerial axes, forming arbuscule-like structures, vesicles and spores; Palaeoendogone gwynne-vaughaniae (gen. nov., sp. nov. Mucoromycotina) colonizes parenchyma in the basal part of the plant, where it is present in intercellular spaces and as intracellular coils but absent from rhizoids. Critical comparisons between the newly discovered Horneophyton endophytes, fungi previously described from the Rhynie Chert and fungal colonization in extant lower land plants reveal several features characteristic of both Mucoromycotina and Glomeromycota. A reappraisal of fungal associations in early land plants indicates that they are more diverse than assumed hitherto, overturning the long-held paradigm that the early endophytes were exclusively Glomeromycota.

  9. Breast and ovarian cancer screening of non-carriers from BRCA1/2 mutation-positive families: 2-year follow-up of cohorts from France and Quebec

    PubMed Central

    Dorval, Michel; Noguès, Catherine; Berthet, Pascaline; Chiquette, Jocelyne; Gauthier-Villars, Marion; Lasset, Christine; Picard, Claude; Plante, Marie; Simard, Jacques; Julian-Reynier, Claire

    2011-01-01

    We described and compared breast and ovarian screening practices in the 2-year period following test result disclosure in female non-carriers from BRCA1/2 mutation-positive families living in two countries, France and Quebec, Canada, which provide universal health care. Four hundred and two (France n=293; Quebec n=109) unaffected female non-carriers from BRCA-proven mutation families provided information about the uptake of mammography, clinical breast examination, breast self-examination, and ovarian ultrasounds using self-administered questionnaires. The frequency of screening practices between study cohorts were compared using logistic regression. Annual mammography was conducted in 23 and 43% of French and Quebecer women participants <50 years of age, respectively (adjusted odds ratio (aOR)=2.72; 95% confidence interval (CI), 1.08–6.81). In women ≥50 years of age, mammography was conducted in 49 and 65% of French and Quebecer participants (aOR=1.77; 95% CI, 0.07–4.51). Overall, 33% of French women and 39% of Quebecer women underwent at least one ovarian ultrasound during the 2-year period following BRCA1/2 test result with no significant difference between cohorts of women <50 years of age. Among older women, Quebecers reported more frequently than French women that they had undergone ultrasound once (aOR=3.00; 95% CI, 1.02–8.83). The frequency of cancer screening practices for female non-carriers from BRCA1/2 mutation-positive families in both France and Quebec exceeded those recommended for similarly aged women in the general population. Our findings highlight the need for clearcut recommendations on the follow-up of women from BRCA1/2 families who are not themselves carriers of a BRCA1/2 mutation. PMID:21248744

  10. EPA Awards Oklahoma over $1.2 million to Reduce Water Contamination Risk in Underground Tanks

    EPA Pesticide Factsheets

    DALLAS - (June 30, 2015) The U.S. Environmental Protection Agency (EPA) has recently awarded the Oklahoma Corporation Conservation Commission $459,000 to respond to petroleum leaks from underground storage tanks (UST). The agency will also receive $

  11. EPA awards $1.2 million brownfields grants to three Arizona communities

    EPA Pesticide Factsheets

    SAN FRANCISCO - The U.S. Environmental Protection Agency announced today that the City of Phoenix, Pima County, and the City of Yuma, Ariz., are among 147 communities nationwide receiving funding to assess and clean up historically contaminated prop

  12. Large $N$ approach to kaon decays and mixing 28 years later: $\\Delta I = 1/2$ rule, $\\hat B_K$ and $\\Delta M_K$

    SciTech Connect

    Buras, Andrzej J.; Gérard, Jean -Marc; Bardeen, William A.

    2014-05-20

    We review and update our results for K → π π decays and K⁰- K¯⁰ mixing obtained by us in the 1980s within an approach based on the dual representation of QCD as a theory of weakly interacting mesons for large N colours. In our analytic approach the dynamics behind the enhancement of ReA0 and suppression of ReA2, the so-called ΔI = 1/2 rule for K → π π decays, has a simple structure: the usual octet enhancement through quark-gluon renormalization group evolution down to the scales O(1 GeV) is continued as a meson evolution down to zero momentum scales at which the factorization of hadronic matrix elements is at work. The inclusion of lowest-lying vector meson contributions in addition to the pseudoscalar ones and of Wilson coefficients in a momentum scheme improves significantly the matching between quark-gluon and meson evolutions. In particular, the anomalous dimension matrix governing the meson evolution exhibits the structure of the known anomalous dimension matrix in the quark-gluon evolution. The recent results on ReA2 and ReA0 from the RBC-UKQC collaboration give support for our approach. In particular, the signs of the two main contractions found numerically by these authors follow uniquely from our analytic approach. At NLO in 1/N we obtain R = ReA0/ReA2= 16.0±1.5 which amounts to an order of magnitude enhancement over the strict large N limit value √2. QCD penguins contribute at 15% level to this result. We also find B^K = 0.73± 0.02, with the smallness of 1/N corrections to the large N value B^K = 3/4 resulting within our approach from an approximate cancellation between pseudoscalar and vector meson one-loop contributions. We summarize the status of ΔMK in this approach.

  13. Large $N$ approach to kaon decays and mixing 28 years later: $$\\Delta I = 1/2$$ rule, $$\\hat B_K$$ and $$\\Delta M_K$$

    DOE PAGES

    Buras, Andrzej J.; Gérard, Jean -Marc; Bardeen, William A.

    2014-05-20

    We review and update our results for K → π π decays and K⁰- K¯⁰ mixing obtained by us in the 1980s within an approach based on the dual representation of QCD as a theory of weakly interacting mesons for large N colours. In our analytic approach the dynamics behind the enhancement of ReA0 and suppression of ReA2, the so-called ΔI = 1/2 rule for K → π π decays, has a simple structure: the usual octet enhancement through quark-gluon renormalization group evolution down to the scales O(1 GeV) is continued as a meson evolution down to zero momentum scalesmore » at which the factorization of hadronic matrix elements is at work. The inclusion of lowest-lying vector meson contributions in addition to the pseudoscalar ones and of Wilson coefficients in a momentum scheme improves significantly the matching between quark-gluon and meson evolutions. In particular, the anomalous dimension matrix governing the meson evolution exhibits the structure of the known anomalous dimension matrix in the quark-gluon evolution. The recent results on ReA2 and ReA0 from the RBC-UKQC collaboration give support for our approach. In particular, the signs of the two main contractions found numerically by these authors follow uniquely from our analytic approach. At NLO in 1/N we obtain R = ReA0/ReA2= 16.0±1.5 which amounts to an order of magnitude enhancement over the strict large N limit value √2. QCD penguins contribute at 15% level to this result. We also find B^K = 0.73± 0.02, with the smallness of 1/N corrections to the large N value B^K = 3/4 resulting within our approach from an approximate cancellation between pseudoscalar and vector meson one-loop contributions. We summarize the status of ΔMK in this approach.« less

  14. Two years' experience of implementing molecular screening of hepatitis B virus, hepatitis C virus and human immunodeficiency virus 1, 2 in Riyadh blood donors.

    PubMed

    Mohamud, Hanat S; Mohamed, Deqa H; Alqahtani, Farjah H; Almajid, Fahad M; Alswat, Khalid; Somily, Ali M

    2016-04-01

    Molecular screening technologies have improved blood safety by reducing the number of window-period transmissions relative to serological screening. In the two years following the introduction of molecular testing in King Khalid University Hospital, Saudi Arabia, 25,920 donor samples were screened in parallel by both serological and molecular techniques for hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV). No HCV or HIV NAT yields were detected. However, molecular screening enabled the interdiction of two confirmed HBV NAT yields. This is only the second report of confirmed HBV NAT yield in the Kingdom of Saudi Arabia, and amongst the few reports in the wider Middle East and North Africa region.

  15. [Protective special shoes for diabetics. Personal experience with a group of high risk diabetics during a 2 and 1/2 year period].

    PubMed

    Záhumenský, E; Adamíková, A

    1993-09-01

    A group of 60 type II diabetics with the risk of development of ulceration of the feet was provided with protective specialized footwear. In the course of 2.5 years in 45 patients who could be evaluated the frequency of relapses of previous ulcerations, the development of first ulcerations and the effect on indicators of immediate high risk of a defect (formation of decubital ulcers, blisters) was investigated, as well as the general biomechanical comfort. In 10 patients with relapsing defects relapses developed twice (20%), no primary ulceration developed. As compared with common footwear, the protective footwear had a favourable effect on the formation of sores and blisters 25 patients (55.5%/ 45/100%) reported improvement of the general comfort when walking. 28 (62.2%) patients make use of the favourable experience with the specialized footwear when selecting shoes or when modifiying standard footwear. A surprising finding was delayed fatigue when walking reported by 35 (77.8%) patients, mitigation of dysaesthesias by 23 (51%), pain in the joints by 14 (31.1%), improved stability by 35 (77.8%) of the patients. With regard of the improvement of some subjective complaints the use of protective footwear can be considered a symptomatic-therapeutic element. According to clinical results specialized footwear has a favourable and protective effect on already damaged feet with a reduced tolerance for combined (mechanical, ischaemic, neurotrophic, infectious) insults. Consistent with data of authors from abroad after a 2-5-year follow-up there was a cca 50% reduction in the number of relapses of ulcerations and amputations as compared with common not modified footwear.

  16. Educational Mismatch and Mortality among Native-Born Workers in Sweden. a 19-Year Longitudinal Study of 2.5 Million Over-Educated, Matched and Under-Educated Individuals, 1990-2008

    ERIC Educational Resources Information Center

    Garcy, Anthony M

    2015-01-01

    This study tests the hypothesis that a disjuncture between an individual's attained level of education and that held by average workers in the individual's occupation leads to higher mortality among those with a prolonged mismatched status. Swedish register data are used in a 19-year longitudinal mortality follow-up study of all causes and…

  17. Educational mismatch and mortality among native-born workers in Sweden. A 19-year longitudinal study of 2.5 million over-educated, matched and under-educated individuals, 1990-2008.

    PubMed

    Garcy, Anthony M

    2015-11-01

    This study tests the hypothesis that a disjuncture between an individual's attained level of education and that held by average workers in the individual's occupation leads to higher mortality among those with a prolonged mismatched status. Swedish register data are used in a 19-year longitudinal mortality follow-up study of all causes and specific causes of mortality. Participants were all men and women born between 1926 and 1985 who were alive on 1 September 1990, who had concurrent information on their attained level of education and the specific occupation or industry they were employed in during this period for at least a consecutive year. An objective measure of educational and occupational mismatch was constructed from these data. Those with a stable, over-educated matched, or under-educated employment status are included in the final analysis (N = 2,482,696). Independent of social, family, employers' characteristics and prior health problems, the findings from a multivariate, stratified Cox regression analysis suggest there is excessive mortality among the over-educated, and a protective effect of under-education among native-born Swedish men and women.

  18. Children Adrift: Educating China's Millions of Migrants.

    ERIC Educational Resources Information Center

    Cao, Haili

    1999-01-01

    The population of migrants moving within China's borders has reached some 80 million, including 2-3 million school-aged children. As migrant workers flock to cities, their children strain urban school systems or receive no education. But independent schools for migrants are illegal and substandard. In some rural provinces, vocational training may…

  19. Literacy--The 877 Million Left Behind.

    ERIC Educational Resources Information Center

    Muller, Anne, Ed.; Murtagh, Teresa, Ed.

    2002-01-01

    In 2000, approximately 877 million adults worldwide were illiterate and 113 million children did not attend school. More than two-thirds of those individuals lived in East and South Asia, and two-thirds were females. Functional illiteracy remains high in developed and developing nations alike. The reasons include weak training in how to teach…

  20. The Million Dollar Bowl. OSHA in the Office.

    ERIC Educational Resources Information Center

    Swartz, Carl

    Accidents to office workers add up to 40,000 injuries and more than 200 deaths a year, amounting to expenses from medical assistance and loss of productivity of $100 million. Leading types of accidents are falling caused by slipping on slick or wet floors, tripping over file drawers, slipping on debris on stairs, injuries from poor lighting,…

  1. Universities Collected $642-Million in Royalties on Inventions in 1999.

    ERIC Educational Resources Information Center

    Blumenstyk, Goldie

    2000-01-01

    U.S. universities collected more than $641 million from royalties on their inventions in the 1999 fiscal year, and they filed for 7,612 patents. Findings from a survey by the Association of University Technology Managers show licensing revenues, patent activity, and income from technology developments of U.S. higher education institutions. (SLD)

  2. 50 million dollar washing machine on-line at Galatia

    SciTech Connect

    Wright, A.

    1985-02-01

    The coal preparation plant at Kerr-McGee's Galatia mine in Illinois is designed to process 2 million ton/year. Details of the coal from the two-seam mine are given and a flow-sheet of the cleaning process is presented.

  3. Paleomagnetic field strength over the last million years

    NASA Astrophysics Data System (ADS)

    Ziegler, L. B.; Johnson, C. L.; Constable, C. G.

    2012-04-01

    Absolute paleomagnetic intensity data derived from thermally magnetized lavas and archeological objects provide information about past geomagnetic field behavior, but the average field strength, its variability, and the expected statistical distribution of these observations remain uncertain despite growing data sets. We present statistical characterizations of the 0-1 Ma field strength, in terms of virtual axial dipole moment (VADM), using data from the PINT, MagIC, and Geomagia50 databases. Uneven temporal sampling and large age uncertainties in the available data produce biased estimates for the mean field and its statistical distribution. We describe and apply bootstrap resampling techniques to correct for these effects. The influence of material type is assessed using independent data compilations to compare Holocene data from lava flows, Submarine Basaltic Glass (SBG), and archeological objects. The comparison to SBG is inconclusive because of dating issues, but paleointensity estimates from lavas are on average about 10% higher than for archeological materials and show greater dispersion. A further interesting basis for comparison is provided by PADM2M, a continuous model of temporal variations in axial dipole moment principally derived from relative paleointensity time series, but calibrated by incorporating absolute measurements. On average, absolute VADMs are higher than the axial dipole moment estimated in PADM2M, with greater spread in the VADM distribution. Both VADM and PADM2M distribution estimates from lavas show more structure than might be expected: neither has a smooth, unimodal distribution despite the large numbers of data used in the estimation. Simulations from a stochastic model based on the geomagnetic field spectrum demonstrate that long period intensity variations can have a strong impact on the observed distributions and could plausibly explain apparent bimodality.

  4. Four hundred million years of silica biomineralization in land plants

    PubMed Central

    Trembath-Reichert, Elizabeth; Wilson, Jonathan Paul; McGlynn, Shawn E.; Fischer, Woodward W.

    2015-01-01

    Biomineralization plays a fundamental role in the global silicon cycle. Grasses are known to mobilize significant quantities of Si in the form of silica biominerals and dominate the terrestrial realm today, but they have relatively recent origins and only rose to taxonomic and ecological prominence within the Cenozoic Era. This raises questions regarding when and how the biological silica cycle evolved. To address these questions, we examined silica abundances of extant members of early-diverging land plant clades, which show that silica biomineralization is widespread across terrestrial plant linages. Particularly high silica abundances are observed in lycophytes and early-diverging ferns. However, silica biomineralization is rare within later-evolving gymnosperms, implying a complex evolutionary history within the seed plants. Electron microscopy and X-ray spectroscopy show that the most common silica-mineralized tissues include the vascular system, epidermal cells, and stomata, which is consistent with the hypothesis that biomineralization in plants is frequently coupled to transpiration. Furthermore, sequence, phylogenetic, and structural analysis of nodulin 26-like intrinsic proteins from diverse plant genomes points to a plastic and ancient capacity for silica accumulation within terrestrial plants. The integration of these two comparative biology approaches demonstrates that silica biomineralization has been an important process for land plants over the course of their >400 My evolutionary history. PMID:25825729

  5. The first 800 million years of earth's history

    NASA Technical Reports Server (NTRS)

    Smith, J. V.

    1981-01-01

    It is pointed out that there is no direct geological information on the first 750 Ma of earth history. Consequently the reported study is based on controversial inferences drawn from the moon, other planets and meteorites, coupled with backward extrapolation from surviving terrestrial rocks, especially those of Archaean age. Aspects of accretion are considered, taking into account cosmochemical and cosmophysical evidence, a new earth model, and convection systems. Attention is given to phase-equilibrium constraints, estimates of heat production, the bombardment history of the moon and implications for the earth, and the nature of the early crust. From a combination of physical, chemical, and petrological arguments, it is concluded that the earth's surface underwent intense volcanism in the pre-Archaean era, and that the rock types were chemically similar to those found in the early Archaean era.

  6. The outer solar system for 200 million years

    NASA Technical Reports Server (NTRS)

    Applegate, J. H.; Douglas, M. R.; Gursel, Y.; Sussman, G. J.; Wisdom, J.

    1986-01-01

    A special-purpose computer is used to integrate the orbits of the outer five planets for more than 100 Myr into the future and more than 100 Myr into the past. The strongest features in the Fourier transforms of the orbital elements of the Jovian planets can be identified with the frequencies predicted by linear secular theory. Many of the weaker features in the Fourier spectra are identified as linear combinations of the basic frequencies. Serious differences are noted between the present measurements and the predictions of Bretagnon (1974). The amplitude of the 3.796 Myr period libration of Pluto's longitude of perihelion is modulated with a period of 34 Myr. Very long periods, on the order of 137 Myr, are also seen. The orbit of Pluto is stable for the duration of the integration; the maximum Liapunov characteristic exponent is less than 10 to the -6.8 power/yr.

  7. Biogeography and diversification of Brassicales: A 103million year tale.

    PubMed

    Cardinal-McTeague, Warren M; Sytsma, Kenneth J; Hall, Jocelyn C

    2016-06-01

    Brassicales is a diverse order perhaps most famous because it houses Brassicaceae and, its premier member, Arabidopsis thaliana. This widely distributed and species-rich lineage has been overlooked as a promising system to investigate patterns of disjunct distributions and diversification rates. We analyzed plastid and mitochondrial sequence data from five gene regions (>8000bp) across 151 taxa to: (1) produce a chronogram for major lineages in Brassicales, including Brassicaceae and Arabidopsis, based on greater taxon sampling across the order and previously overlooked fossil evidence, (2) examine biogeographical ancestral range estimations and disjunct distributions in BioGeoBEARS, and (3) determine where shifts in species diversification occur using BAMM. The evolution and radiation of the Brassicales began 103Mya and was linked to a series of inter-continental vicariant, long-distance dispersal, and land bridge migration events. North America appears to be a significant area for early stem lineages in the order. Shifts to Australia then African are evident at nodes near the core Brassicales, which diverged 68.5Mya (HPD=75.6-62.0). This estimated age combined with fossil evidence, indicates that some New World clades embedded amongst Old World relatives (e.g., New World capparoids) are the result of different long distance dispersal events, whereas others may be best explained by land bridge migration (e.g., Forchhammeria). Based on these analyses, the Brassicaceae crown group diverged in Europe/Northern Africa in the Eocene, circa 43.4Mya (HPD=46.6-40.3) and Arabidopsis separated from close congeners circa 10.4Mya. These ages fall between divergent dates that were previously published, suggesting we are slowly converging on a robust age estimate for the family. Three significant shifts in species diversification are observed in the order: (1) 58Mya at the crown of Capparaceae, Cleomaceae and Brassicaceae, (2) 38Mya at the crown of Resedaceae+Stixis clade, and (3) 21Mya at the crown of the tribes Brassiceae and Sisymbrieae within Brassicaceae.

  8. The million-year wait for macroevolutionary bursts.

    PubMed

    Uyeda, Josef C; Hansen, Thomas F; Arnold, Stevan J; Pienaar, Jason

    2011-09-20

    We lack a comprehensive understanding of evolutionary pattern and process because short-term and long-term data have rarely been combined into a single analytical framework. Here we test alternative models of phenotypic evolution using a dataset of unprecedented size and temporal span (over 8,000 data points). The data are body-size measurements taken from historical studies, the fossil record, and among-species comparative data representing mammals, squamates, and birds. By analyzing this large dataset, we identify stochastic models that can explain evolutionary patterns on both short and long timescales and reveal a remarkably consistent pattern in the timing of divergence across taxonomic groups. Even though rapid, short-term evolution often occurs in intervals shorter than 1 Myr, the changes are constrained and do not accumulate over time. Over longer intervals (1-360 Myr), this pattern of bounded evolution yields to a pattern of increasing divergence with time. The best-fitting model to explain this pattern is a model that combines rare but substantial bursts of phenotypic change with bounded fluctuations on shorter timescales. We suggest that these rare bursts reflect permanent changes in adaptive zones, whereas the short-term fluctuations represent local variations in niche optima due to restricted environmental variation within a stable adaptive zone.

  9. Interspecific interactions through 2 million years: are competitive outcomes predictable?

    PubMed Central

    Di Martino, Emanuela; Rust, Seabourne

    2016-01-01

    Ecological interactions affect the survival and reproduction of individuals. However, ecological interactions are notoriously difficult to measure in extinct populations, hindering our understanding of how the outcomes of interactions such as competition vary in time and influence long-term evolutionary changes. Here, the outcomes of spatial competition in a temporally continuous community over evolutionary timescales are presented for the first time. Our research domain is encrusting cheilostome bryozoans from the Wanganui Basin of New Zealand over a ca 2 Myr time period (Pleistocene to Recent). We find that a subset of species can be identified as consistent winners, and others as consistent losers, in the sense that they win or lose interspecific competitive encounters statistically more often than the null hypothesis of 50%. Most species do not improve or worsen in their competitive abilities through the 2 Myr period, but a minority of species are winners in some intervals and losers in others. We found that conspecifics tend to cluster spatially and interact more often than expected under a null hypothesis: most of these are stand-off interactions where the two colonies involved stopped growing at edges of encounter. Counterintuitively, competitive ability has no bearing on ecological dominance. PMID:27581885

  10. 350 Million Years Old and Still Going Strong.

    ERIC Educational Resources Information Center

    Cowles, Kathleen Letcher

    1984-01-01

    Suggesting using the cockroach as a free resource to teach students lessons on population dynamics and habitat management that apply to all wildlife. Presents suggestions on how and where to locate and trap cockroaches. Emphasizes the importance of controlling their population without using dangerous pesticides. (BC)

  11. Four hundred million years of silica biomineralization in land plants

    NASA Astrophysics Data System (ADS)

    Trembath-Reichert, Elizabeth; Wilson, Jonathan Paul; McGlynn, Shawn E.; Fischer, Woodward W.

    2015-04-01

    Biomineralization plays a fundamental role in the global silicon cycle. Grasses are known to mobilize significant quantities of Si in the form of silica biominerals and dominate the terrestrial realm today, but they have relatively recent origins and only rose to taxonomic and ecological prominence within the Cenozoic Era. This raises questions regarding when and how the biological silica cycle evolved. To address these questions, we examined silica abundances of extant members of early-diverging land plant clades, which show that silica biomineralization is widespread across terrestrial plant linages. Particularly high silica abundances are observed in lycophytes and early-diverging ferns. However, silica biomineralization is rare within later-evolving gymnosperms, implying a complex evolutionary history within the seed plants. Electron microscopy and X-ray spectroscopy show that the most common silica-mineralized tissues include the vascular system, epidermal cells, and stomata, which is consistent with the hypothesis that biomineralization in plants is frequently coupled to transpiration. Furthermore, sequence, phylogenetic, and structural analysis of nodulin 26-like intrinsic proteins from diverse plant genomes points to a plastic and ancient capacity for silica accumulation within terrestrial plants. The integration of these two comparative biology approaches demonstrates that silica biomineralization has been an important process for land plants over the course of their >400 My evolutionary history.

  12. The million-year wait for macroevolutionary bursts

    PubMed Central

    Uyeda, Josef C.; Hansen, Thomas F.; Arnold, Stevan J.; Pienaar, Jason

    2011-01-01

    We lack a comprehensive understanding of evolutionary pattern and process because short-term and long-term data have rarely been combined into a single analytical framework. Here we test alternative models of phenotypic evolution using a dataset of unprecedented size and temporal span (over 8,000 data points). The data are body-size measurements taken from historical studies, the fossil record, and among-species comparative data representing mammals, squamates, and birds. By analyzing this large dataset, we identify stochastic models that can explain evolutionary patterns on both short and long timescales and reveal a remarkably consistent pattern in the timing of divergence across taxonomic groups. Even though rapid, short-term evolution often occurs in intervals shorter than 1 Myr, the changes are constrained and do not accumulate over time. Over longer intervals (1–360 Myr), this pattern of bounded evolution yields to a pattern of increasing divergence with time. The best-fitting model to explain this pattern is a model that combines rare but substantial bursts of phenotypic change with bounded fluctuations on shorter timescales. We suggest that these rare bursts reflect permanent changes in adaptive zones, whereas the short-term fluctuations represent local variations in niche optima due to restricted environmental variation within a stable adaptive zone. PMID:21873251

  13. Gates Foundation donates $25 million for AIDS vaccine.

    PubMed

    1999-05-07

    The International AIDS Vaccine Initiative (IAVI) received a $25 million five-year grant from Bill and Melinda Gates through the William H. Gates Foundation. This is the largest gift seen in the AIDS epidemic, and will allow IAVI to more than double vaccine development efforts. IAVI is currently developing two potential vaccines, hopes to study three others, and is working with the business community to insure that a successful vaccine is affordable in developing countries. With 16,000 new infections occurring daily, a vaccine is seen as the most effective way to stop the epidemic. The William H. Gates Foundation had donated $1.5 million to IAVI and $100 million for programs to speed the delivery of vaccines to children in poor countries. Internet addresses are included for both IAVI and the William H. Gates Foundation.

  14. Enhancing the view of a million galaxies

    NASA Astrophysics Data System (ADS)

    2004-06-01

    physical properties and distribution of galaxies do not skew the results. About four years ago, ESA's XMM-Newton observatory and NAOJ's Subaru Telescope began a deep survey of a region of sky located in the southern constellation Cetus (the 'Whale'), now known as the Subaru/XMM-Newton Deep Survey (SXDS) field. The SXDS covers a roughly square patch in the sky, measuring about 1.3 degree on a side, or about seven times the area of the full moon and nearly 1000 times larger than the area of the famous Hubble Deep Field. Both observatories have devoted a considerable amount of time to the SXDS. The XMM-Newton observations represent the deepest and most sensitive wide-area X-ray survey ever carried out by XMM-Newton, totalling over one hundred hours of exposure time. The Subaru Telescope has stared at this field for over two hundred hours, in four different colours, revealing details which are hundred million times fainter than what can be seen with the naked eye. Over a thousand X-ray sources are found in the XMM-Newton images. Some of them are nearby stars with very active coronas that radiate in the X-ray domain, but the largest majority are far-flung active galaxies hiding powerful black holes in their nuclei. Other sources include distant clusters of galaxies, located up to eight thousand million light years away. Since X-rays travel in space at a finite speed, XMM-Newton gives us a view of these galaxies when they were much younger and less evolved than now. By comparing these images with those of nearby galaxies, astronomers can infer how they have evolved in the course of the last several thousand million years, or about three quarters of the life of the Universe. The true virtue of the SXDS is that it allows for a seamless comparison and combination of the XMM-Newton images, which provide an X-ray view of the most energetic phenomena in the Universe, with the Subaru data, offering a picture in visible light of where stars form in galaxies. The combined SXDS images

  15. 1,2-Diphenylhydrazine

    Integrated Risk Information System (IRIS)

    1,2 - Diphenylhydrazine ; CASRN 122 - 66 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  16. 1,2-Dibromoethane

    Integrated Risk Information System (IRIS)

    EPA 635 / R - 04 / 067 www.epa.gov / iris TOXICOLOGICAL REVIEW OF 1,2 - DIBROMOETHANE ( CAS No . 106 - 93 - 4 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) June 2004 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been revie

  17. 1,2-Dichloropropane

    Integrated Risk Information System (IRIS)

    1,2 - Dichloropropane ; CASRN 78 - 87 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  18. 1,2-Dichlorobenzene

    Integrated Risk Information System (IRIS)

    1,2 - Dichlorobenzene ; CASRN 95 - 50 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  19. 1,2-Dichloroethane

    Integrated Risk Information System (IRIS)

    1,2 - Dichloroethane ; CASRN 107 - 06 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  20. Corning Inc.: Proposed Changes at Glass Plant Indicate $26 Million in Potential Savings

    SciTech Connect

    2004-01-01

    In 2000, the Corning glass plant in Greenville, Ohio, consumed almost 114 million kWh of electricity and nearly 308,000 MMBtu of natural gas in its glassmaking processes for a total cost of approximately $6.4 million. A plant-wide assessment indicated that improvement projects could save nearly $26 million and reduce natural gas use by 122,900 MMBtu per year, reduce electrical use by 72,300,000 kWh per year, and reduce CO2 emissions by 180 million pounds per year.

  1. Leading the Maricopa Millions OER Project

    ERIC Educational Resources Information Center

    Raneri, April; Young, Lisa

    2016-01-01

    With a reduced number of students purchasing required and necessary textbooks, higher education leaders must look to new opportunities to increase student success. While open educational resources have addressed this issue, they have not received widespread support from faculty, staff, and administrators. The Maricopa Millions OER Project: Scaling…

  2. Clustering Millions of Faces by Identity.

    PubMed

    Otto, Charles; Wang, Dayong; Jain, Anil

    2017-03-07

    Given a large collection of unlabeled face images, we address the problem of clustering faces into an unknown number of identities. This problem is of interest in social media, law enforcement, and other applications, where the number of faces can be of the order of hundreds of million, while the number of identities (clusters) can range from a few thousand to millions. To address the challenges of run-time complexity and cluster quality, we present an approximate Rank-Order clustering algorithm that performs better than popular clustering algorithms (k-Means and Spectral). Our experiments include clustering up to 123 million face images into over 10 million clusters. Clustering results are analyzed in terms of external (known face labels) and internal (unknown face labels) quality measures, and run-time. Our algorithm achieves an F-measure of 0:87 on the LFW benchmark (13K faces of 5; 749 individuals), which drops to 0:27 on the largest dataset considered (13K faces in LFW + 123M distractor images). Additionally, we show that frames in the YouTube benchmark can be clustered with an F-measure of 0:71. An internal per-cluster quality measure is developed to rank individual clusters for manual exploration of high quality clusters that are compact and isolated.

  3. Learning Our Way to One Million

    ERIC Educational Resources Information Center

    Whitin, David J.

    2008-01-01

    David Schwartz's classic book "How Much Is a Million?" can be the catalyst for sparking many interesting mathematical investigations. This article describes five episodes in which children in grades 2-5 all heard this familiar story read aloud to them. At each grade level, they were encouraged to think of their own way to explore the concept of…

  4. One Half Million Mile Solar Filament

    NASA Video Gallery

    NASA’s Solar Dynamics Observatory (SDO) captures a very long, whip-like solar filament extending over half a million miles in a long arc above the sun’s surface. Filaments are cooler clouds of ...

  5. Emulating a million machines to investigate botnets.

    SciTech Connect

    Rudish, Donald W.

    2010-06-01

    Researchers at Sandia National Laboratories in Livermore, California are creating what is in effect a vast digital petridish able to hold one million operating systems at once in an effort to study the behavior of rogue programs known as botnets. Botnets are used extensively by malicious computer hackers to steal computing power fron Internet-connected computers. The hackers harness the stolen resources into a scattered but powerful computer that can be used to send spam, execute phishing, scams or steal digital information. These remote-controlled 'distributed computers' are difficult to observe and track. Botnets may take over parts of tens of thousands or in some cases even millions of computers, making them among the world's most powerful computers for some applications.

  6. Over 30 million psychedelic users in the United States.

    PubMed

    Krebs, Teri S; Johansen, Pål-Ørjan

    2013-01-01

    We estimated lifetime prevalence of psychedelic use (lysergic acid diethylamide (LSD), psilocybin (magic mushrooms), mescaline, and peyote) by age category using data from a 2010 US population survey of 57,873 individuals aged 12 years and older. There were approximately 32 million lifetime psychedelic users in the US in 2010; including 17% of people aged 21 to 64 years (22% of males and 12% of females). Rate of lifetime psychedelic use was greatest among people aged 30 to 34 (total 20%, including 26% of males and 15% of females).

  7. Million-degree plasma pervading the extended Orion Nebula.

    PubMed

    Güdel, Manuel; Briggs, Kevin R; Montmerle, Thierry; Audard, Marc; Rebull, Luisa; Skinner, Stephen L

    2008-01-18

    Most stars form as members of large associations within dense, very cold (10 to 100 kelvin) molecular clouds. The nearby giant molecular cloud in Orion hosts several thousand stars of ages less than a few million years, many of which are located in or around the famous Orion Nebula, a prominent gas structure illuminated and ionized by a small group of massive stars (the Trapezium). We present x-ray observations obtained with the X-ray Multi-Mirror satellite XMM-Newton, revealing that a hot plasma with a temperature of 1.7 to 2.1 million kelvin pervades the southwest extension of the nebula. The plasma flows into the adjacent interstellar medium. This x-ray outflow phenomenon must be widespread throughout our Galaxy.

  8. Kumbh Mela 2013: Healthcare for the millions

    PubMed Central

    Cariappa, M.P.; Singh, B.P.; Mahen, A.; Bansal, A.S.

    2015-01-01

    Mass gatherings pose challenges to healthcare systems anywhere in the world. The Kumbh Mela 2013 at Allahabad, India was the largest gathering of humanity in the history of mankind, and posed an exciting challenge to the provision of healthcare services. At the finale of the Mela, it was estimated that about 120 million pilgrims had visited the site. Equitable geospatial distribution of adhoc health care facilities were created on a standardised template with integrated planning of evacuation modalities. Innovative and low cost response measures for disaster mitigation were implemented. Emergency patient management kits were prepared and stocked across the health care facilities for crisis response. Dynamic resource allocation (in terms of manpower and supplies) based on patient volumes was done on a daily basis, in response to feedback. An adhoc mega township created on the banks of a perennial river (Ganga) in the Indian subcontinent for accommodating millions of Hindu pilgrims. Conventional mindset of merely providing limited and static healthcare through adhoc facilities was done away with. Innovative concepts such as riverine ambulances and disaster kits were introduced. Managing the medical aspects of a mass gathering mega event requires allocation of adequate funds, proactive and integrated medical planning and preparedness. PMID:26288497

  9. Genotype Imputation with Millions of Reference Samples.

    PubMed

    Browning, Brian L; Browning, Sharon R

    2016-01-07

    We present a genotype imputation method that scales to millions of reference samples. The imputation method, based on the Li and Stephens model and implemented in Beagle v.4.1, is parallelized and memory efficient, making it well suited to multi-core computer processors. It achieves fast, accurate, and memory-efficient genotype imputation by restricting the probability model to markers that are genotyped in the target samples and by performing linear interpolation to impute ungenotyped variants. We compare Beagle v.4.1 with Impute2 and Minimac3 by using 1000 Genomes Project data, UK10K Project data, and simulated data. All three methods have similar accuracy but different memory requirements and different computation times. When imputing 10 Mb of sequence data from 50,000 reference samples, Beagle's throughput was more than 100× greater than Impute2's throughput on our computer servers. When imputing 10 Mb of sequence data from 200,000 reference samples in VCF format, Minimac3 consumed 26× more memory per computational thread and 15× more CPU time than Beagle. We demonstrate that Beagle v.4.1 scales to much larger reference panels by performing imputation from a simulated reference panel having 5 million samples and a mean marker density of one marker per four base pairs.

  10. Millions of extra deaths a result of shortfalls in ODA.

    PubMed

    1997-01-01

    This news brief summarizes the conclusions of a newly released report by the UN Population Fund for its executive board. The report is "Meeting the Goals of the 1994 International Conference on Population and Development (ICPD): Consequences of Resource Shortfalls up to the Year 2000." Donor spending, including World Bank loans, increased by 40% in 1994, increased by 40% in 1995, and stabilized. The ICPD indicates a need for an additional $5.7 billion in donor assistance, an increase of 23% each year until the year 2000. Donors must meet their 33% share of the US$17 billion required in the year 2000 and the $21.7 billion by 2015. This level of assistance is needed in order to meet the goals of the ICPD agreed upon by attending countries. Developing countries have continued to increase their allocations for reproductive health in accordance with the ICPD recommendations. Most donor countries were not close to meeting the official development assistance target of 0.7% of gross national product. France, Italy, and Belgium have been slow in responding to population program assistance. However, Norway and the Netherlands have passed laws requiring that 4% of their official development assistance be applied to population programs. Denmark is cooperative. Japan is a leading donor, followed by the UK. It is estimated in the UN executive board report that during 1995-2000 shortfalls in assistance will result in at least 120 million additional unwanted pregnancies, 49 million abortions, 5 million infant and child deaths, and 65,000 maternal deaths.

  11. Dose Reconstruction for the Million Worker Study: Status and Guidelines

    DOE PAGES

    Bouville, André; Toohey, Richard E.; Boice, John D.; ...

    2015-02-01

    The primary aim of the epidemiologic study of one million U.S. radiation workers and veterans (the Million-Worker study) is to provide scientifically valid information on the level of radiation risk when exposures are received gradually over time, and not acutely as was the case for Japanese atomic bomb survivors. The primary outcome of the epidemiological study is cancer mortality but other causes of death such as cardiovascular disease and cerebrovascular disease will be evaluated. The success of the study is tied to the validity of the dose reconstruction approaches to provide unbiased estimates of organ-specific radiation absorbed doses and theirmore » accompanying uncertainties. The dosimetry aspects for the Million-Worker study are challenging in that they address diverse exposure scenarios for diverse occupational groups being studied over a period of up to 70 years. The dosimetric issues differ among the varied exposed populations that are considered: atomic veterans, DOE workers exposed to both penetrating radiation and intakes of radionuclides, nuclear power plant workers, medical radiation workers, and industrial radiographers. While a major source of radiation exposure to the study population comes from external gamma-ray or x-ray sources, for certain of the study groups there is a meaningful component of radionuclide intakes that require internal radiation dosimetry measures. Scientific Committee 6-9 has been established by NCRP to produce a report on the comprehensive organ dose assessment (including uncertainty analysis) for the Million-Worker study. The Committee’s report will cover the specifics of practical dose reconstruction for the ongoing epidemiologic studies with uncertainty analysis discussions and will be a specific application of the guidance provided in NCRP Reports 158, 163, 164, and 171. The main role of the Committee is to provide guidelines to the various groups of dosimetrists involved in the various components of the Million

  12. Dose Reconstruction for the Million Worker Study: Status and Guidelines

    SciTech Connect

    Bouville, André; Toohey, Richard E.; Boice, John D.; Beck, Harold L.; Dauer, Larry T.; Eckerman, Keith F.; Hagemeyer, Derek; Leggett, Richard W.; Mumma, Michael T.; Napier, Bruce; Pryor, Kathy H.; Rosenstein, Marvin; Schauer, David A.; Sherbini, Sami; Stram, Daniel O.; Thompson, James L.; Till, John E.; Yoder, Craig; Zeitlin, Cary

    2015-02-01

    The primary aim of the epidemiologic study of one million U.S. radiation workers and veterans (the Million-Worker study) is to provide scientifically valid information on the level of radiation risk when exposures are received gradually over time, and not acutely as was the case for Japanese atomic bomb survivors. The primary outcome of the epidemiological study is cancer mortality but other causes of death such as cardiovascular disease and cerebrovascular disease will be evaluated. The success of the study is tied to the validity of the dose reconstruction approaches to provide unbiased estimates of organ-specific radiation absorbed doses and their accompanying uncertainties. The dosimetry aspects for the Million-Worker study are challenging in that they address diverse exposure scenarios for diverse occupational groups being studied over a period of up to 70 years. The dosimetric issues differ among the varied exposed populations that are considered: atomic veterans, DOE workers exposed to both penetrating radiation and intakes of radionuclides, nuclear power plant workers, medical radiation workers, and industrial radiographers. While a major source of radiation exposure to the study population comes from external gamma-ray or x-ray sources, for certain of the study groups there is a meaningful component of radionuclide intakes that require internal radiation dosimetry measures. Scientific Committee 6-9 has been established by NCRP to produce a report on the comprehensive organ dose assessment (including uncertainty analysis) for the Million-Worker study. The Committee’s report will cover the specifics of practical dose reconstruction for the ongoing epidemiologic studies with uncertainty analysis discussions and will be a specific application of the guidance provided in NCRP Reports 158, 163, 164, and 171. The main role of the Committee is to provide guidelines to the various groups of dosimetrists involved in the various components of the Million

  13. Saudis map $450 million gulf spill cleanup

    SciTech Connect

    Not Available

    1991-11-18

    This paper reports on Saudi Arabia which has earmarked about $450 million to clean up Persian Gulf beaches polluted by history's worst oil spills, created during the Persian Gulf crisis. Details of the proposed cleanup measures were outlined by Saudi environmental officials at a seminar on the environment in Dubai, OPEC News Agency reported. The seminar was sponsored by the Gulf Area Oil Companies Mutual Aid Organization, an environmental cooperative agency set up by Persian Gulf governments. Meantime, a Saudi government report has outlined early efforts designed to contain the massive oil spills that hit the Saudi coast before oil could contaminate water intakes at the huge desalination plants serving Riyadh and cooling water facilities at Al Jubail.

  14. Disaster care for 15 million Californians.

    PubMed

    ROBINSON, H G

    1960-08-01

    The urgency of the crisis following a nuclear attack staggers the imagination. We would have thousands or millions of survivors making a desperate struggle to survive. Safe water supplies and waste-disposal systems would be gone. In some areas, there would be little or no food or shelter. Yet California has already manned a medical arsenal that is second to none in the United States. We have stored 115 emergency hospitals at strategic points, and through the county medical associations we have appointed cadres including physicians, nurses and technicians. Plans have been made for workers who will assist in setting up the hospitals and first aid stations. In our future operations we will continue to place strong emphasis on the medical phase of our program of disaster care.The program would be just as essential in the event of major natural disaster as nuclear war. Our objective is a simple one. We are seeking to preserve the human resources which are necessary for recovery.California's medical profession, with the allied professions of nursing and technical skills, has a vital interest in continuing operations to the maximum extent even under the most trying conditions.

  15. WISE PHOTOMETRY FOR 400 MILLION SDSS SOURCES

    SciTech Connect

    Lang, Dustin; Hogg, David W.; Schlegel, David J.

    2016-02-15

    We present photometry of images from the Wide-Field Infrared Survey Explorer (WISE) of over 400 million sources detected by the Sloan Digital Sky Survey (SDSS). We use a “forced photometry” technique, using measured SDSS source positions, star–galaxy classification, and galaxy profiles to define the sources whose fluxes are to be measured in the WISE images. We perform photometry with The Tractor image modeling code, working on our “unWISE” coaddds and taking account of the WISE point-spread function and a noise model. The result is a measurement of the flux of each SDSS source in each WISE band. Many sources have little flux in the WISE bands, so often the measurements we report are consistent with zero given our uncertainties. However, for many sources we get 3σ or 4σ measurements; these sources would not be reported by the “official” WISE pipeline and will not appear in the WISE catalog, yet they can be highly informative for some scientific questions. In addition, these small-signal measurements can be used in stacking analyses at the catalog level. The forced photometry approach has the advantage that we measure a consistent set of sources between SDSS and WISE, taking advantage of the resolution and depth of the SDSS images to interpret the WISE images; objects that are resolved in SDSS but blended together in WISE still have accurate measurements in our photometry. Our results, and the code used to produce them, are publicly available at http://unwise.me.

  16. WISE Photometry for 400 Million SDSS Sources

    NASA Astrophysics Data System (ADS)

    Lang, Dustin; Hogg, David W.; Schlegel, David J.

    2016-02-01

    We present photometry of images from the Wide-Field Infrared Survey Explorer (WISE) of over 400 million sources detected by the Sloan Digital Sky Survey (SDSS). We use a “forced photometry” technique, using measured SDSS source positions, star-galaxy classification, and galaxy profiles to define the sources whose fluxes are to be measured in the WISE images. We perform photometry with The Tractor image modeling code, working on our “unWISE” coaddds and taking account of the WISE point-spread function and a noise model. The result is a measurement of the flux of each SDSS source in each WISE band. Many sources have little flux in the WISE bands, so often the measurements we report are consistent with zero given our uncertainties. However, for many sources we get 3σ or 4σ measurements; these sources would not be reported by the “official” WISE pipeline and will not appear in the WISE catalog, yet they can be highly informative for some scientific questions. In addition, these small-signal measurements can be used in stacking analyses at the catalog level. The forced photometry approach has the advantage that we measure a consistent set of sources between SDSS and WISE, taking advantage of the resolution and depth of the SDSS images to interpret the WISE images; objects that are resolved in SDSS but blended together in WISE still have accurate measurements in our photometry. Our results, and the code used to produce them, are publicly available at http://unwise.me.

  17. Large data analysis: automatic visual personal identification in a demography of 1.2 billion persons

    NASA Astrophysics Data System (ADS)

    Daugman, John

    2014-05-01

    The largest biometric deployment in history is now underway in India, where the Government is enrolling the iris patterns (among other data) of all 1.2 billion citizens. The purpose of the Unique Identification Authority of India (UIDAI) is to ensure fair access to welfare benefits and entitlements, to reduce fraud, and enhance social inclusion. Only a minority of Indian citizens have bank accounts; only 4 percent possess passports; and less than half of all aid money reaches its intended recipients. A person who lacks any means of establishing their identity is excluded from entitlements and does not officially exist; thus the slogan of UIDAI is: To give the poor an identity." This ambitious program enrolls a million people every day, across 36,000 stations run by 83 agencies, with a 3-year completion target for the entire national population. The halfway point was recently passed with more than 600 million persons now enrolled. In order to detect and prevent duplicate identities, every iris pattern that is enrolled is first compared against all others enrolled so far; thus the daily workflow now requires 600 trillion (or 600 million-million) iris cross-comparisons. Avoiding identity collisions (False Matches) requires high biometric entropy, and achieving the tremendous match speed requires phase bit coding. Both of these requirements are being delivered operationally by wavelet methods developed by the author for encoding and comparing iris patterns, which will be the focus of this Large Data Award" presentation.

  18. From 5 Million to 20 Million a Year: The Challenge of Scale, Quality and Relevance in India's TVET

    ERIC Educational Resources Information Center

    Mehrotra, Santosh

    2014-01-01

    In the first decade of this century, India became one of the world's fastest growing large economies, and began to face serious skill-related shortages of workers. Its TVET system has not responded adequately to the growth in demand for semi-skilled and skilled workers. This article describes six sets of reforms that India's educational planners…

  19. Lung cancer in never smokers in the UK Million Women Study

    PubMed Central

    Peto, Richard; Green, Jane; Reeves, Gillian K.; Beral, Valerie

    2016-01-01

    To assess directly the effects of various risk factors on lung cancer incidence among never smokers, large prospective studies are needed. In a cohort of 1.2 million UK women without prior cancer, half (634,039) reported that they had never smoked. Mean age at recruitment was 55 (SD5) years, and during 14 (SD3) years of follow‐up, 0.2% (1,469) of these never smokers developed lung cancer. Cox regression was used to estimate relative risks (RRs) of lung cancer for 34 potential risk factors, of which 31 were nonsignificant (p > 0.05). The remaining three risk factors were associated with a significantly increased incidence of lung cancer in never smokers: non‐white vs. white ethnicity (RR = 2.34, 95% CI 1.55–3.52, p < 0.001), asthma requiring treatment vs. not (RR = 1.32, 1.10–1.58, p = 0.003) and taller stature (height ≥ 165 cm vs. <160 cm: RR = 1.16, 1.03–1.32, p = 0.02). There was little association with other sociodemographic, anthropometric or hormonal factors, or with dietary intakes of meat, fish, fruit, vegetables and fiber. The findings were not materially affected by restricting the analyses to adenocarcinomas, the most common histological type among never smokers. PMID:26954623

  20. The Path to a $300-Million Donation

    ERIC Educational Resources Information Center

    Masterson, Kathryn

    2008-01-01

    The first time Edward A. Snyder, dean of the University of Chicago's graduate business school, asked David G. Booth to donate money to name something on the campus, Mr. Booth said no. Five years later, the University's Graduate School of Business is named the University of Chicago Booth School of Business, after Mr. Booth gave what is valued as a…

  1. cis-1,2-Dichloroethylene

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 09 / 006 F www.epa.gov / iris TOXICOLOGICAL REVIEW OF cis - 1,2 - DICHLOROETHYLENE and trans - 1,2 - DICHLOROETHYLENE ( CAS Nos . cis : 156 - 59 - 2 ; trans : 156 - 60 - 5 ; mixture : 540 - 59 - 0 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS )

  2. Talking dirty: how to save a million lives.

    PubMed

    Curtis, V

    2003-06-01

    Infectious diseases are still the number one threat to public health in developing countries. Diarrhoeal diseases alone are responsible for the deaths of at least 2 million children yearly - hygiene is paramount to resolving this problem. The function of hygienic behaviour is to prevent the transmission of the agents of infection. The most effective way of stopping infection is to stop faecal material getting into the child's environment by safe disposal of faeces and washing hands with soap once faecal material has contaminated them in the home. A review of the literature on handwashing puts it top in a list of possible interventions to prevent diarrhoea. Handwashing with soap has been calculated to save a million lives. However, few people do wash their hands with soap at these critical times. Obtaining a massive increase in handwashing worldwide requires a sea-change in thinking. Initial results from a new programme led by the World Bank, with many partner organisations, suggest that health is low on people's list of motives, rather, hands are washed to remove dirt, to rinse food off after eating, to make hands look and smell good, and as an act of motherly caring. Professional consumer and market research agencies are being used to work with the soap industry to design professional communications programmes to reach whole populations in Ghana and India. Tools and techniques for marketing handwashing and for measuring the actual impact on behaviour will be applied in new public-private handwashing programmes, which are to start up soon in Nepal, China, Peru and Senegal.

  3. Strategies to choose from millions of imputed sequence variants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Millions of sequence variants are known, but subsets are needed for routine genomic predictions or to include on genotyping arrays. Variant selection and imputation strategies were tested using 26 984 simulated reference bulls, of which 1 000 had 30 million sequence variants, 773 had 600 000 markers...

  4. 1,1,2-Trichloroethane

    Integrated Risk Information System (IRIS)

    1,1,2 - Trichloroethane ; CASRN 79 - 00 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcino

  5. 1,2,4-Tribromobenzene

    Integrated Risk Information System (IRIS)

    1,2,4 - Tribromobenzene ; CASRN 615 - 54 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  6. 1,1,2-Trichloropropane

    Integrated Risk Information System (IRIS)

    1,1,2 - Trichloropropane ; CASRN 598 - 77 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarci

  7. 1,2,3-Trichloropropane

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 08 / 010F www.epa.gov / iris TOXICOLOGICAL REVIEW OF 1,2,3 - TRICHLOROPROPANE ( CAS No . 96 - 18 - 4 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) September 2009 U.S . Environmental Protection Agency Washington DC i DISCLAIMER This document ha

  8. trans-1,2-Dichloroethylene

    Integrated Risk Information System (IRIS)

    trans - 1,2 - Dichloroethylene ; CASRN 156 - 60 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for No

  9. 1,2,4-Trichlorobenzene

    Integrated Risk Information System (IRIS)

    1,2,4 - Trichlorobenzene ; CASRN 120 - 82 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarci

  10. 1,2-Epoxybutane (EBU)

    Integrated Risk Information System (IRIS)

    1,2 - Epoxybutane ( EBU ) ; CASRN 106 - 88 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarc

  11. U.S. EPA Announces More than $182 Million for Drinking Water and Wastewater Infrastructure Projects in California

    EPA Pesticide Factsheets

    The City of Carlsbad is using approximately $30 million through a one percent interest State Revolving Fund loan and an additional $7 million in other funding to expand its current water recycling facility capacity from 4,100 acre-feet per year to 7,235 ac

  12. The Geological Grading Scale: Every million Points Counts!

    NASA Astrophysics Data System (ADS)

    Stegman, D. R.; Cooper, C. M.

    2006-12-01

    The concept of geological time, ranging from thousands to billions of years, is naturally quite difficult for students to grasp initially, as it is much longer than the timescales over which they experience everyday life. Moreover, universities operate on a few key timescales (hourly lectures, weekly assignments, mid-term examinations) to which students' maximum attention is focused, largely driven by graded assessment. The geological grading scale exploits the overwhelming interest students have in grades as an opportunity to instill familiarity with geological time. With the geological grading scale, the number of possible points/marks/grades available in the course is scaled to 4.5 billion points --- collapsing the entirety of Earth history into one semester. Alternatively, geological time can be compressed into each assignment, with scores for weekly homeworks not worth 100 points each, but 4.5 billion! Homeworks left incomplete with questions unanswered lose 100's of millions of points - equivalent to missing the Paleozoic era. The expected quality of presentation for problem sets can be established with great impact in the first week by docking assignments an insignificant amount points for handing in messy work; though likely more points than they've lost in their entire schooling history combined. Use this grading scale and your students will gradually begin to appreciate exactly how much time represents a geological blink of the eye.

  13. $1.5 million female condom order awarded.

    PubMed

    1997-12-01

    The Female Health Co. of Chicago, Illinois, has reported receiving an order for 1.5 million female condoms from South Africa's Department of Health. Shipments are scheduled to begin immediately and are expected to be completed by early 1998. Earlier, South Africa ordered 90,000 female condoms in order to test the device. This order is part of the company's multi-year agreement with the Joint UN Program on AIDS (UNAIDS) which provides a special price based upon global public sector demand. The launch of the female condom in South Africa is just one of a series planned in Africa and other areas of the developing world. The globalization of the female condom, albeit in its early stages, affords the Female Health Co. with the opportunity to explore other options for the future development of its business. The company has engaged Vector Securities International, Inc. to help identify, develop, and evaluate those options. The female condom is currently marketed in the US, the UK, Canada, South Korea, Taiwan, and Holland, and will soon be launched in Brazil. Female Health Co. is also engaged in discussions with potential partners for Europe, the US, India, China, and other countries. The female condom was also recently launched in Zimbabwe as pert of the Joint UNAIDS, and an application had been submitted to Koseisho for marketing approval in Japan.

  14. $156 million budget increase to fight HIV/AIDS in African American & other minority communities.

    PubMed

    1998-12-01

    A series of initiatives was established to invest $156 million in efforts to fight HIV/AIDS in minority populations, where AIDS is still a leading cause of death among men and women between 25 and 44 years of age. The initiatives will target specific communities and includes technical assistance and increased access to care. Specific goals of the initiatives are discussed.

  15. Fourier spectroscopy with a one-million-point transformation

    NASA Technical Reports Server (NTRS)

    Connes, J.; Delouis, H.; Connes, P.; Guelachvili, G.; Maillard, J.; Michel, G.

    1972-01-01

    A new type of interferometer for use in Fourier spectroscopy has been devised at the Aime Cotton Laboratory of the National Center for Scientific Research (CNRS), Orsay, France. With this interferometer and newly developed computational techniques, interferograms comprising as many as one million samples can now be transformed. The techniques are described, and examples of spectra of thorium and holmium, derived from one million-point interferograms, are presented.

  16. Photographer: JPL P-21741 C Range: 2.6 million kilometers (1.6 million miles) This picture of Io,

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer: JPL P-21741 C Range: 2.6 million kilometers (1.6 million miles) This picture of Io, taken by Voyager 1, shows the region of the Jovian moon which will be monitored for volcanic eruptions by Voyager 2 during the 'Io movie' sequence. The white and orange patches probably are deposits of sulphur compounds and other volcanic materials. The Voyager 2 pictures of this region will be much more detailed.

  17. Photographer: JPL P-21741 BW Range: 2.6 million kilometers (1.6 million miles) This picture of Io,

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer: JPL P-21741 BW Range: 2.6 million kilometers (1.6 million miles) This picture of Io, taken by Voyager 1, shows the region of the Jovian moon which will be monitored for volcanic eruptions by Voyager 2 during the 'Io movie' sequence. The white and orange patches probably are deposits of sulphur compounds and other volcanic materials. The Voyager 2 pictures of this region will be much more detailed.

  18. New Zealand's 70 million sheep create 350 million methane gallons daily

    SciTech Connect

    Not Available

    1987-07-01

    If you could hook up a sheep to the carburetor of a car, you could run it for several kilometers a day. To power the same vehicle by people, you'd need a whole football team and a couple of kegs of beer. That observation is made by David Lowe, a geophysicist with the New Zealand Institute of Nuclear Sciences in Wellington. Scientists are studying the methane output because of its potential serious threat by contributing to global warming via the greenhouse effect. According to a report in the Wall Street Journal, analysis of ancient air bubbles trapped in Antarctic ice shows that 30,000 years ago methane concentration in the Earth's atmosphere was only a third as much as it is today. Radioactive dating can distinguish ages of different types of methane in the air, and researchers hope to quantify sources from sheep, swamps, people or industry. Sheep methane is collected at a local agricultural university from sheep with tubes protruding from their intestines. Sample collector Lowe alternates specimens from the university and the digester tank at the sewage treatment plant. The cleanest air samples, by contrast, are collected by Lowe at Baring Head, the first outcrop of land Antarctic winds hit after crossing thousands of miles of open sea. So far, Lowe and his colleagues have found that 75% of methane in the atmosphere is biological and of very recent origin. While the research goes on, New Zealand's sheep population continue to churn out 2.5 billion gallons of methane every week.

  19. Million Hearts: Key to Collaboration to Reduce Heart Disease

    ERIC Educational Resources Information Center

    Brinkman, Patricia

    2016-01-01

    Extension has taught successful classes to address heart disease, yet heart disease remains the number one killer in the United States. The U.S. government's Million Hearts initiative seeks collaboration among colleges, local and state health departments, Extension and other organizations, and medical providers in imparting a consistent message…

  20. The MET Project: The Wrong 45 Million Dollar Question

    ERIC Educational Resources Information Center

    Gabriel, Rachael; Allington, Richard

    2012-01-01

    In 2009, the Bill and Melinda Gates Foundation funded the investigation of a $45 million question: How can we identify and develop effective teaching? Now that the findings from their Measures of Effective Teaching (MET) project have been released, it's clear they asked a simpler question, namely, What other measures match up well with value-added…

  1. The Million-Dollar President, Soon to Be Commonplace?

    ERIC Educational Resources Information Center

    Chronicle of Higher Education, 2006

    2006-01-01

    This article reports the results of a survey conducted by "The Chronicle" that examined college presidents' compensation. The survey found a 53-percent increase in presidents' compensation. While the salaries do not have an eye-popping quotient as those of corporate CEOs'--whose median compensation was just over $6 million among the 350 largest US…

  2. Harvard Will Seek $30-Million for Program on Business Ethics.

    ERIC Educational Resources Information Center

    Desruisseaux, Paul

    1987-01-01

    The Harvard University Business School will establish a new program on ethics, leadership, and competitiveness in business, to be financed with $30 million in private gifts. The major contributor is the chairman of the United States Securities and Exchange Commission, an alumnus and former ambassador. (MSE)

  3. Millions Learning: Scaling up Quality Education in Developing Countries

    ERIC Educational Resources Information Center

    Robinson, Jenny Perlman; Winthrop, Rebecca

    2016-01-01

    "Millions Learning: Scaling up Quality Education in Developing Countries" tells the story of where and how quality education has scaled in low- and middle-income countries. The story emerges from wide-ranging research on scaling and learning, including 14 in-depth case studies from around the globe. Ultimately, "Millions…

  4. Uncovered: Social Security, Retirement Uncertainty, and 1 Million Teachers

    ERIC Educational Resources Information Center

    Kan, Leslie; Aldeman, Chad

    2014-01-01

    Retirement savings are often described as a three-legged stool: Social Security, employer retirement plans, and personal savings. For many American workers, Social Security is the most consistent portion of the three-legged model, providing a solid plank of retirement savings. But nationwide, more than 1 million teachers--about 40 percent of all…

  5. Universities' Royalty Income Increased 33% in 1997, Reaching $446-Million.

    ERIC Educational Resources Information Center

    Basinger, Julianne

    1999-01-01

    According to an annual survey, 132 U.S. research universities earned over $446 million in royalties from inventions in fiscal 1997, and received 2,239 patents. The University of California was the top earner. Data provided on the top-earning institutions includes dollar amount of adjusted gross royalties received, number of licenses generating…

  6. EPA Provides Puerto Rico $27 Million for Clean Water Projects

    EPA Pesticide Factsheets

    (New York, N.Y.) The U.S. Environmental Protection Agency has allotted $27 million to Puerto Rico to help finance improvements to water projects that are essential to protecting public health and the environment. The funds will be used to finance water qua

  7. EPA Provides New Jersey $74 Million for Clean Water Projects

    EPA Pesticide Factsheets

    (New York, N.Y.) The U.S. Environmental Protection Agency has allotted $74 million to New Jersey to help finance improvements to water projects that are essential to protecting public health and the environment. The funds will be used to finance water qual

  8. New Program Aims $300-Million at Young Biomedical Researchers

    ERIC Educational Resources Information Center

    Goodall, Hurley

    2008-01-01

    Medical scientists just starting at universities have been, more and more often, left empty-handed when the federal government awards grants. To offset this, the Howard Hughes Medical Institute, a nonprofit organization dedicated to medical research, announced a new program that will award $300-million to as many as 70 young scientists. The Early…

  9. Capital Campaigns to Raise $100-Million or More.

    ERIC Educational Resources Information Center

    Chronicle of Higher Education, 1987

    1987-01-01

    A table lists the colleges and universities that have initiated capital campaigns to raise $100-million or more. Names of the universities, their goals, public announcement dates, completion dates, and gifts and pledges as of June 30, 1987 are given. (MLW)

  10. ONE MILLION GALLON WATER TANK, PUMP HEADER PIPE (AT LEFT), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    ONE MILLION GALLON WATER TANK, PUMP HEADER PIPE (AT LEFT), HEADER BYPASS PIPE (AT RIGHT), AND PUMPHOUSE FOUNDATIONS. Looking northeast - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Flame Deflector Water System, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  11. Lender Allowed to Keep Federal Overpayment of $278-Million

    ERIC Educational Resources Information Center

    Field, Kelly

    2007-01-01

    This article reports that the US Education Department has announced that it will not require the National Education Loan Network (Nelnet), a major for-profit student-loan provider based in Nebraska, to return hundreds of millions of dollars in government subsidies, but it will cut off the overpayments going forward. The department will also stop…

  12. Photographer : JPL Range : 4.2 million km. ( 2.6 million miles ) Jupiter's moon Europa, the size of

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Photographer : JPL Range : 4.2 million km. ( 2.6 million miles ) Jupiter's moon Europa, the size of earth's moon, is apparently covered by water ice, as indicated by ground spectrometers and its brightness. In this view, global scale dark sreaks discovered by Voyager 1 that criss-cross the the satelite are becoming visible. Bright rayed impact craters, which are abundant on Ganymede and Callisto, would be easily visible at this range, suggesting that Europa's surface is young and that the streaks are reflections of currently active internal dynamic processes.

  13. Determinants of spermatogenesis recovery among workers exposed to 1,2-dibromo-3-chloropropane

    SciTech Connect

    Olsen, G.W.; Lanham, J.M.; Bodner, K.M.; Hylton, D.B.; Bond, G.G. )

    1990-10-01

    The purpose of this study was to investigate the determinants of spermatogenesis recovery among 30 azoospermic and 17 oligospermic workers who had a maximum of 18 months of exposure to 1,2-dibromo-3-chloropropane during 1976 to 1977. A maximum of 11 years of follow-up data were examined. Of the 26 azoospermic subjects who voluntarily participated in follow-up, 19 (73.0%) showed evidence of spermatogenesis recovery. Thirteen azoospermic subjects recovered to normospermic levels; however, their mean most recent sperm count (44.4 million/mL) was significantly lower (P less than .01) than the mean (88.8 million/mL) of the 17 oligospermic subjects who recovered to normospermic levels. The lack of spermatogenesis recovery was definitively shown to be job (drumming and canning) and, possibly, age related. Duration of exposure and the initial 1977 categorization of exposure (high, moderate, and low) were not predictive of recovery. Testicular atrophy was observed with azoospermia, and the testicles subsequently increased in size among those azoospermic subjects who returned to normospermic levels. The follicle-stimulating hormone level in 1977 was significantly associated with azoospermia as well as the likelihood of return to normospermia among the azoospermic subjects.

  14. Treatment of late syphilis with 2.4 million units benzathine penicillin G (BPG): tolerance of single versus divided doses.

    PubMed

    Janier, Michel; Libar, Eliane; Bonnet, Annie; Meunier, Patrick; Tabet, Magda; Mathourais, Monique; Paterour, Christine; Porcher, Raphael

    2012-05-01

    Although there is no data in the literature, some textbooks recommend fractioning the injection of benzathine penicillin G (BPG) for alleviating the pain. In a monocentric study done in 50 consecutive patients with late syphilis. Patients were assigned to receive 1 dose of 2.4 million units BPG intramuscularly the first week and 2 doses of 1.2 million units BPG in each buttock the second week. In the third week, patients were asked to choose between the 2 options. It was demonstrated that the 2 techniques were equally well tolerated and equally preferred by patients.

  15. Impact of a combined community and primary care prevention strategy on all-cause and cardiovascular mortality: a cohort analysis based on 1 million person-years of follow-up in Västerbotten County, Sweden, during 1990–2006

    PubMed Central

    Blomstedt, Yulia; Norberg, Margareta; Stenlund, Hans; Nyström, Lennarth; Lönnberg, Göran; Boman, Kurt; Wall, Stig; Weinehall, Lars

    2015-01-01

    Objective To evaluate the impact of the Västerbotten Intervention Programme (VIP) by comparing all eligible individuals (target group impact) according to the intention-to-treat principle and VIP participants with the general Swedish population. Design Dynamic cohort study. Setting/participants All individuals aged 40, 50 or 60 years, residing in Västerbotten County, Sweden, between 1990 and 2006 (N=101 918) were followed from their first opportunity to participate in the VIP until age 75, study end point or prior death. Intervention The VIP is a systematic, long-term, county-wide cardiovascular disease (CVD) intervention that is performed within the primary healthcare setting and combines individual and population approaches. The core component is a health dialogue based on a physical examination and a comprehensive questionnaire at the ages of 40, 50 and 60 years. Primary outcomes All-cause and CVD mortality. Results For the target group, there were 5646 deaths observed over 1 054 607 person-years. Compared to Sweden at large, the standardised all-cause mortality ratio was 90.6% (95% CI 88.2% to 93.0%): for women 87.9% (95% CI 84.1% to 91.7%) and for men 92.2% (95% CI 89.2% to 95.3%). For CVD, the ratio was 95.0% (95% CI 90.7% to 99.4%): for women 90.4% (95% CI 82.6% to 98.7%) and for men 96.8% (95% CI 91.7 to 102.0). For participants, subject to further impact as well as selection, when compared to Sweden at large, the standardised all-cause mortality ratio was 66.3% (95% CI 63.7% to 69.0%), whereas the CVD ratio was 68.9% (95% CI 64.2% to 73.9%). For the target group as well as for the participants, standardised mortality ratios for all-cause mortality were reduced within all educational strata. Conclusions The study suggests that the VIP model of CVD prevention is able to impact on all-cause and cardiovascular mortality when evaluated according to the intention-to-treat principle. PMID:26685034

  16. Zooniverse - Real science online with more than a million people. (Invited)

    NASA Astrophysics Data System (ADS)

    Smith, A.; Lynn, S.; Lintott, C.; Whyte, L.; Borden, K. A.

    2013-12-01

    The Zooniverse (zooniverse.org) began in 2007 with the launch of Galaxy Zoo, a project in which more than 175,000 people provided shape analyses of more than 1 million galaxy images sourced from the Sloan Digital Sky Survey. These galaxy 'classifications', some 60 million in total, have since been used to produce more than 50 peer-reviewed publications based not only on the original research goals of the project but also because of serendipitous discoveries made by the volunteer community. Based upon the success of Galaxy Zoo the team have gone on to develop more than 25 web-based citizen science projects, all with a strong research focus in a range of subjects from astronomy to zoology where human-based analysis still exceeds that of machine intelligence. Over the past 6 years Zooniverse projects have collected more than 300 million data analyses from over 1 million volunteers providing fantastically rich datasets for not only the individuals working to produce research from their project but also the machine learning and computer vision research communities. This talk will focus on the core 'method' by which Zooniverse projects are developed and lessons learned by the Zooniverse team developing citizen science projects across a range of disciplines.

  17. [L1-2 lumbar disc herniation: a case report].

    PubMed

    Monobe, T; Fujita, T; Nakaue, Y; Nishi, N

    1996-03-01

    A 49-year-old female presented a two-year history of pain in the right thigh and lower back. Neurological examination on admission demonstrated weakness of the right iliopsoas and quadriceps, hypesthesia on the right L1-2 dermatome. Radiological examination including myelography, CT myelography and discography disclosed an L1-2 herniated disc. Sagittal MRI also revealed an L1-2, an L4-5 and L5-S1 protruded disc. A posterior microdiscectomy (Love's method) was performed for the L1-2 disc. A controlateral protruded disc which compressed the L-2 nerve root was identified and partially removed. The postoperative myelography showed residual disc. The patient was free from pain and regained normal sensorimotor function. Love's posterior microdiscectomy has a disadvantage in that the operative field is limited. Careful surgical procedure was needed to avoid injury to nerve roots and the cauda equina in a tight L1-2 lumbar canal.

  18. Learning-assisted theorem proving with millions of lemmas☆

    PubMed Central

    Kaliszyk, Cezary; Urban, Josef

    2015-01-01

    Large formal mathematical libraries consist of millions of atomic inference steps that give rise to a corresponding number of proved statements (lemmas). Analogously to the informal mathematical practice, only a tiny fraction of such statements is named and re-used in later proofs by formal mathematicians. In this work, we suggest and implement criteria defining the estimated usefulness of the HOL Light lemmas for proving further theorems. We use these criteria to mine the large inference graph of the lemmas in the HOL Light and Flyspeck libraries, adding up to millions of the best lemmas to the pool of statements that can be re-used in later proofs. We show that in combination with learning-based relevance filtering, such methods significantly strengthen automated theorem proving of new conjectures over large formal mathematical libraries such as Flyspeck. PMID:26525678

  19. Improving Multi-Million Virtual Rank MPI Execution in

    SciTech Connect

    Perumalla, Kalyan S; Park, Alfred J

    2011-01-01

    (MUPI) is a parallel discrete event simulator designed for enabling software-based experimentation via simulated execution across a range of synthetic to unmodified parallel programs using the Message Passing Interface (MPI) with millions of tasks. Here, we report work in progress in improving the efficiency of . Among the issues uncovered are the scaling problems with implementing barriers and intertask message ordering. Preliminary performance shows the possibility of supporting hundreds of virtual MPI ranks per real processor core. Performance improvements of at least 2 are observed, and enable execution of benchmark MPI runs with over 16 million virtual ranks synchronized in a discrete event fashion on as few as 16,128 real cores of a Cray XT5.

  20. Berkeley Lab scientists develop criteria for $20 million energy challenge

    ScienceCinema

    Walker, Iain

    2016-07-12

    Berkeley Labs Iain Walker and his colleagues in environmental energy research helped the Siebel Foundation develop the criteria for its Energy Free Home Challenge, which comes with a $20 million global incentive prize. The Challenge is a competition to create a new generation of systems and technologies for practical homes that realize a net-zero, non-renewable energy footprint without increasing the cost of ownership. It is open to everyone everywhere — university teams to handymen and hobbyists.

  1. Sky Brightness Analysis using a Million GEODSS Observations

    NASA Astrophysics Data System (ADS)

    Mandeville, W. Jody; McLaughlin, Tim; Six, Steve; Hollm, Rick

    2012-09-01

    Brightness of the sky background due to lunar phase and location can dramatically affect the limiting magnitude of astronomical detectors. Formerly, theoretical models have attained limited data sets with 10-20% differences between model and observation. This paper compares and contrasts previous investigations with over a million data points collected from various GEODSS sites located around the world and attempts to refine predictive modeling of sky brightness for use in scheduling as well as modeling and simulation tools.

  2. Side Elevation, End Elevation, Cross Section, 1/2 Roof Plan, 1/2 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Side Elevation, End Elevation, Cross Section, 1/2 Roof Plan, 1/2 Reflected Plan, 1/2 Floor Plan, 1/2 Reflected Plan - Jack's Mill Covered Bridge, Spanning Henderson Creek, Oquawka, Henderson County, IL

  3. Energy tax price tag for CPI: $1. 2 billion, jobs, and production

    SciTech Connect

    Begley, R.

    1993-03-03

    If President Clinton's proposed energy tax had been fully in place last year, it would have cost the US chemical industry an additional $1.2 billion and 9,900 jobs, according to Chemical Manufacturers Association (CMA; Washington) estimates. It also would have driven output down 3% and prices up 5%, CMA says. Allen Lenz, CMA director/trade and economics, says the increase in production costs that would accompany the tax will not be shared by foreign competitors, cannot be neutralized with higher border taxes because of existing trade agreements, and provides another reason to move production offshore. Worse, the US chemical industry's generally impressive trade surplus declined by $2.5 billion last year, and a further drop is projected for this year. The margin of error gets thinner all the time as competition increases, Lenz says. We're not concerned only with the chemical industry, but the rest of US-based manufacturing because they taken half our output, he adds. One problem is the energy intensiveness of the chemical process industries-a CMA report says that 55% of the cost of producing ethylene glycol is energy related. And double taxation of such things as coproducts returned for credit to oil refineries could add up to $115 million/year, the report says.

  4. Ten million and one penguins, or, lessons learned from booting millions of virtual machines on HPC systems.

    SciTech Connect

    Minnich, Ronald G.; Rudish, Donald W.

    2009-01-01

    In this paper we describe Megatux, a set of tools we are developing for rapid provisioning of millions of virtual machines and controlling and monitoring them, as well as what we've learned from booting one million Linux virtual machines on the Thunderbird (4660 nodes) and 550,000 Linux virtual machines on the Hyperion (1024 nodes) clusters. As might be expected, our tools use hierarchical structures. In contrast to existing HPC systems, our tools do not require perfect hardware; that all systems be booted at the same time; and static configuration files that define the role of each node. While we believe these tools will be useful for future HPC systems, we are using them today to construct botnets. Botnets have been in the news recently, as discoveries of their scale (millions of infected machines for even a single botnet) and their reach (global) and their impact on organizations (devastating in financial costs and time lost to recovery) have become more apparent. A distinguishing feature of botnets is their emergent behavior: fairly simple operational rule sets can result in behavior that cannot be predicted. In general, there is no reducible understanding of how a large network will behave ahead of 'running it'. 'Running it' means observing the actual network in operation or simulating/emulating it. Unfortunately, this behavior is only seen at scale, i.e. when at minimum 10s of thousands of machines are infected. To add to the problem, botnets typically change at least 11% of the machines they are using in any given week, and this changing population is an integral part of their behavior. The use of virtual machines to assist in the forensics of malware is not new to the cyber security world. Reverse engineering techniques often use virtual machines in combination with code debuggers. Nevertheless, this task largely remains a manual process to get past code obfuscation and is inherently slow. As part of our cyber security work at Sandia National Laboratories

  5. Millions can be saved through better energy management in federal hospitals

    SciTech Connect

    Not Available

    1982-09-01

    A comparison of the energy savings achieved by hospitals of the Navy, Veterans Administration, and Indian Health service - all of which have energy conservation programs - with that of five non-federal hospitals having aggressive energy management programs indicated that these agencies could save between $16 million and $55 million more each year if additional energy-saving measures were adopted. The investment required to achieve these savings would be quickly recouped. GAO believes that additional energy-saving opportunities also exist at the Army and Air Force hospitals. Two important program elements - technical audits to identify cost-effective energy conservation measures and accountability to ensure that the measures are implemented - are generally missing or incomplete in federal hospitals' energy conservation efforts. By increasing emphasis on these elements, federal agencies could achieve many of the yet unrealized energy savings.

  6. [The Six Million Dollar Man: from fiction to reality].

    PubMed

    Langeveld, C H Kees

    2013-01-01

    The term 'bionic' has been in existence since 1958, but only gained general recognition from the television series 'The Six Million Dollar Man'. Following a crash, the central figure in this series - test pilot Steve Austin - has an eye, an arm and both legs replaced by prostheses which make him stronger and faster than a normal person. This story is based on the science fiction book 'Cyborg' by Martin Caidin. In the world of comic books and films there are a number of examples of people who are given superhuman powers by having technological gadgets built in. Although the latter is not yet possible, the bionic human has now become reality.

  7. MULTI - MILLION - TURN BEAM POSITION MONITORS FOR RHIC.

    SciTech Connect

    SATOGATA,T.CAMERON,P.CERNIGLIA,P.CUPOLO,J.DAWSON,CDEGEN,CMEAD,JVETTER,K

    2003-05-12

    During the RHIC 2003 run, two beam position monitors (BPMs) in each transverse plane in the RHIC blue ring were upgraded with high-capacity mezzanine cards. This upgrade provided these planes with the capability to digitize up to 128 million consecutive turns of RHIC beam, or almost 30 minutes of continuous beam centroid phase space evolution for a single RHIC bunch. This paper describes necessary hardware and software changes and initial system performance. We discuss early uses and results for diagnosis of coherent beam oscillations, turn-by-turn (TBT) acquisition through a RHIC acceleration ramp, and ac-dipole nonlinear dynamics studies.

  8. A Million-Second Chandra View of Cassiopeia A

    NASA Technical Reports Server (NTRS)

    Hwang, Una; Laming, J. Martin; Badenes, Carles; Berendse, Fred; Blondin, John; Cioffi, Denis; DeLaney, Tracey; Dewey, Daniel; Fesen, Robert; Flanagan, Kathryn A.

    2004-01-01

    We introduce a million-second observation of the supernova remnant Cassiopeia A with the Chandra X-ray Observatory. The bipolar structure of the Si-rich ejecta (NE jet and SW counterpart) is clearly evident in the new images, and their chemical similarity is confirmed by their spectra. These are most likely due to jets of ejecta as opposed to cavities in the circumstellar medium, since we can reject simple models for the latter. The properties of these jets and the Fe-rich ejecta will provide clues to the explosion of Cas A.

  9. 7 CFR 1.2 - Policy.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Policy. 1.2 Section 1.2 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Official Records § 1.2 Policy. (a) Agencies of USDA shall comply with the time limits set forth in the FOIA and in this subpart for responding to...

  10. 29 CFR 1.2 - Definitions. 1

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 1 2012-07-01 2012-07-01 false Definitions. 1 1.2 Section 1.2 Labor Office of the Secretary of Labor PROCEDURES FOR PREDETERMINATION OF WAGE RATES § 1.2 Definitions. 1 1 These definitions... Assistance Act of 1972. (e) The term Wage Determinations OnLine (WDOL) shall mean the Government Internet...

  11. 29 CFR 1.2 - Definitions. 1

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 1 2014-07-01 2013-07-01 true Definitions. 1 1.2 Section 1.2 Labor Office of the Secretary of Labor PROCEDURES FOR PREDETERMINATION OF WAGE RATES § 1.2 Definitions. 1 1 These definitions are... Assistance Act of 1972. (e) The term Wage Determinations OnLine (WDOL) shall mean the Government Internet...

  12. 29 CFR 1.2 - Definitions. 1

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 1 2011-07-01 2011-07-01 false Definitions. 1 1.2 Section 1.2 Labor Office of the Secretary of Labor PROCEDURES FOR PREDETERMINATION OF WAGE RATES § 1.2 Definitions. 1 1 These definitions... Assistance Act of 1972. (e) The term Wage Determinations OnLine (WDOL) shall mean the Government Internet...

  13. 29 CFR 1.2 - Definitions. 1

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 1 2013-07-01 2013-07-01 false Definitions. 1 1.2 Section 1.2 Labor Office of the Secretary of Labor PROCEDURES FOR PREDETERMINATION OF WAGE RATES § 1.2 Definitions. 1 1 These definitions... Assistance Act of 1972. (e) The term Wage Determinations OnLine (WDOL) shall mean the Government Internet...

  14. 11 CFR 1.2 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Definitions. 1.2 Section 1.2 Federal Elections FEDERAL ELECTION COMMISSION PRIVACY ACT § 1.2 Definitions. As defined in the Privacy Act of 1974 and for the purposes of this part, unless otherwise required by the context, the following terms shall...

  15. 45 CFR 1210.1-2 - Scope.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Scope. 1210.1-2 Section 1210.1-2 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE VISTA TRAINEE DESELECTION AND VOLUNTEER EARLY TERMINATION PROCEDURES General § 1210.1-2 Scope. (a) This part applies to all Trainees and...

  16. 45 CFR 1211.1-2 - Applicability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Applicability. 1211.1-2 Section 1211.1-2 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE VOLUNTEER GRIEVANCE PROCEDURES § 1211.1-2 Applicability. This part applies to all volunteers enrolled under part A of title I of the...

  17. 43 CFR 2812.1-2 - Contents.

    Code of Federal Regulations, 2010 CFR

    2006-10-01

    ... 43 Public Lands: Interior 2 2006-10-01 2006-10-01 false Contents. 2812.1-2 Section 2812.1-2 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT... Bay Revested Lands § 2812.1-2 Contents. (a) An individual applicant and each member of...

  18. 43 CFR 2812.1-2 - Contents.

    Code of Federal Regulations, 2010 CFR

    1997-10-01

    ... 43 Public Lands: Interior 2 1997-10-01 1997-10-01 false Contents. 2812.1-2 Section 2812.1-2 LAND RESOURCE MANAGEMENT (2000) TRAMROADS AND LOGGING ROADS Over O. and C. and Coos Bay Revested Lands § 2812.1-2 Contents. (a) An individual applicant and each member of any unincorporated association which...

  19. Rates of BRCA1/2 mutation testing among young survivors of breast cancer.

    PubMed

    Kehl, Kenneth L; Shen, Chan; Litton, Jennifer K; Arun, Banu; Giordano, Sharon H

    2016-01-01

    Guidelines in the United States recommend consideration of testing for mutations in the BRCA1 and BRCA2 genes for women diagnosed with breast cancer under age 45. Identification of mutations among survivors has implications for secondary prevention and familial risk reduction. Although only 10 % of breast cancers are diagnosed under age 45, there are approximately 2.8 million breast cancer survivors in the United States, such that the young survivor population likely numbers in the hundreds of thousands. However, little is known about genetic testing rates in this population. We assessed trends in BRCA1/2 testing among breast cancer survivors who were under age 45 at diagnosis and were treated from 2005 to 2012. Using insurance claims from a national database (MarketScan), we identified incident breast cancer cases among (1) women aged ≤40 and (2) women aged 41-45. We measured BRCA1/2 testing using Kaplan-Meier analysis and Cox proportional hazards models. Among 26,985 patients analyzed, BRCA1/2 testing rates increased with each year of diagnosis from 2005 to 2012 (P < 0.001). However, among women treated in earlier years, testing rates did not approach those of patients treated later, even after extended follow-up (median time from surgery to testing among patients treated in 2005, not reached; median time to testing among patients treated in 2012, 0.2 months for women aged ≤40 and 1.0 month for women aged 41-45). Women aged 41-45 had lower rates than women aged ≤40 throughout the analysis period (P < 0.001 for each year). BRCA1/2 testing rates among young women with incident breast cancer increased substantially in the last decade. However, most survivors treated in earlier years have never been tested. Our results demonstrate a need to better incorporate genetic counseling into survivorship and primary care for this population.

  20. Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years

    PubMed Central

    Crampton, James S.; Cody, Rosie D.; Levy, Richard; Harwood, David; McKay, Robert; Naish, Tim R.

    2016-01-01

    It is not clear how Southern Ocean phytoplankton communities, which form the base of the marine food web and are a crucial element of the carbon cycle, respond to major environmental disturbance. Here, we use a new model ensemble reconstruction of diatom speciation and extinction rates to examine phytoplankton response to climate change in the southern high latitudes over the past 15 My. We identify five major episodes of species turnover (origination rate plus extinction rate) that were coincident with times of cooling in southern high-latitude climate, Antarctic ice sheet growth across the continental shelves, and associated seasonal sea-ice expansion across the Southern Ocean. We infer that past plankton turnover occurred when a warmer-than-present climate was terminated by a major period of glaciation that resulted in loss of open-ocean habitat south of the polar front, driving non-ice adapted diatoms to regional or global extinction. These findings suggest, therefore, that Southern Ocean phytoplankton communities tolerate “baseline” variability on glacial–interglacial timescales but are sensitive to large-scale changes in mean climate state driven by a combination of long-period variations in orbital forcing and atmospheric carbon dioxide perturbations. PMID:27274061

  1. Almost a spider: a 305-million-year-old fossil arachnid and spider origins

    PubMed Central

    Garwood, Russell J.; Dunlop, Jason A.; Selden, Paul A.; Spencer, Alan R. T.; Atwood, Robert C.; Vo, Nghia T.; Drakopoulos, Michael

    2016-01-01

    Spiders are an important animal group, with a long history. Details of their origins remain limited, with little knowledge of their stem group, and no insights into the sequence of character acquisition during spider evolution. We describe a new fossil arachnid, Idmonarachne brasieri gen. et sp. nov. from the Late Carboniferous (Stephanian, ca 305–299 Ma) of Montceau-les-Mines, France. It is three-dimensionally preserved within a siderite concretion, allowing both laboratory- and synchrotron-based phase-contrast computed tomography reconstruction. The latter is a first for siderite-hosted fossils and has allowed us to investigate fine anatomical details. Although distinctly spider-like in habitus, this remarkable fossil lacks a key diagnostic character of Araneae: spinnerets on the underside of the opisthosoma. It also lacks a flagelliform telson found in the recently recognized, spider-related, Devonian–Permian Uraraneida. Cladistic analysis resolves our new fossil as sister group to the spiders: the spider stem-group comprises the uraraneids and I. brasieri. While we are unable to demonstrate the presence of spigots in this fossil, the recovered phylogeny suggests the earliest character to evolve on the spider stem-group is the secretion of silk. This would have been followed by the loss of a flagelliform telson, and then the ability to spin silk using spinnerets. This last innovation defines the true spiders, significantly post-dates the origins of silk, and may be a key to the group's success. The Montceau-les-Mines locality has previously yielded a mesothele spider (with spinnerets). Evidently, Late Palaeozoic spiders lived alongside Palaeozoic arachnid grades which approached the spider condition, but did not express the full suite of crown-group autapomorphies. PMID:27030415

  2. A unique coral biomineralization pattern has resisted 40 million years of major ocean chemistry change

    PubMed Central

    Stolarski, Jarosław; Bosellini, Francesca R.; Wallace, Carden C.; Gothmann, Anne M.; Mazur, Maciej; Domart-Coulon, Isabelle; Gutner-Hoch, Eldad; Neuser, Rolf D.; Levy, Oren; Shemesh, Aldo; Meibom, Anders

    2016-01-01

    Today coral reefs are threatened by changes to seawater conditions associated with rapid anthropogenic global climate change. Yet, since the Cenozoic, these organisms have experienced major fluctuations in atmospheric CO2 levels (from greenhouse conditions of high pCO2 in the Eocene to low pCO2 ice-house conditions in the Oligocene-Miocene) and a dramatically changing ocean Mg/Ca ratio. Here we show that the most diverse, widespread, and abundant reef-building coral genus Acropora (20 morphological groups and 150 living species) has not only survived these environmental changes, but has maintained its distinct skeletal biomineralization pattern for at least 40 My: Well-preserved fossil Acropora skeletons from the Eocene, Oligocene, and Miocene show ultra-structures indistinguishable from those of extant representatives of the genus and their aragonitic skeleton Mg/Ca ratios trace the inferred ocean Mg/Ca ratio precisely since the Eocene. Therefore, among marine biogenic carbonate fossils, well-preserved acroporid skeletons represent material with very high potential for reconstruction of ancient ocean chemistry. PMID:27302371

  3. Impacts and tectonism in Earth and moon history of the past 3800 million years

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1992-01-01

    The moon's surface, unlike the Earth's, displays a comparatively clear record of its past bombardment history for the last 3800 Myr, the time since active lunar tectonism under the massive premare bombardment ended. From Baldwin's (1987) tabulation of estimated ages for a representative sample of large lunar craters younger than 3800 Ma, six major cratering episodes can be discerned. These six bombardment episodes, which must have affected the Earth too, appear to match in time the six major episodes of orogenic tectonism on Earth, despite typical resolution errors of +/- 100 Myr and the great uncertainties of the two chronologies. Since more highly resolved events during the Cenozoic and Mesozoic Eras suggest the same correlation, it is possible that large impacts have influenced plate tectonics and other aspects of geologic history, perhaps by triggering flood basalt eruptions.

  4. Episodes of terrestrial geologic activity during the past 260 million years - A quantitative approach

    NASA Technical Reports Server (NTRS)

    Rampino, Michael R.; Caldeira, Ken

    1992-01-01

    Records of major geologic events of the past about 260 Myr including: biologic extinction events, ocean-anoxic and black-shale events, major changes in sea level, major evaporite (salt) deposits, continental flood-basalt eruptions, first-order discontinuities in sea-floor spreading, and major mountain building events, have been aggregated and analyzed with moving-window and spectral techniques that facilitate recognition of clustering and possible cyclicity. Significant clustering of events suggests a model in which changes in rates and directions of sea-floor spreading ('ridge jumps') are associated with episodic rifting, volcanism, mountain building, global sea level and changes in the composition of the earth's atmosphere via the carbon cycle. The geologic data formally show a statistically significant underlying periodicity of 26.6 Myr for the Mesozoic and Cenozoic. Phase information suggests that the most recent maximum of the cycle occurred with the last 9 Myr, and may be close to the present time.

  5. Metabolic dominance of bivalves predates brachiopod diversity decline by more than 150 million years.

    PubMed

    Payne, Jonathan L; Heim, Noel A; Knope, Matthew L; McClain, Craig R

    2014-05-22

    Brachiopods and bivalves feed in similar ways and have occupied the same environments through geological time, but brachiopods were far more diverse and abundant in the Palaeozoic whereas bivalves dominate the post-Palaeozoic, suggesting a transition in ecological dominance 250 Ma. However, diversity and abundance data alone may not adequately describe key changes in ecosystem function, such as metabolic activity. Here, we use newly compiled body size data for 6066 genera of bivalves and brachiopods to calculate metabolic rates and revisit this question from the perspective of energy use, finding that bivalves already accounted for a larger share of metabolic activity in Palaeozoic oceans. We also find that the metabolic activity of bivalves has increased by more than two orders of magnitude over this interval, whereas brachiopod metabolic activity has declined by more than 50%. Consequently, the increase in bivalve energy metabolism must have occurred via the acquisition of new food resources rather than through the displacement of brachiopods. The canonical view of a mid-Phanerozoic transition from brachiopod to bivalve dominance results from a focus on taxonomic diversity and numerical abundance as measures of ecological importance. From a metabolic perspective, the oceans have always belonged to the clams.

  6. Time-resolved 2-million-year-old supernova activity discovered in Earth's microfossil record.

    PubMed

    Ludwig, Peter; Bishop, Shawn; Egli, Ramon; Chernenko, Valentyna; Deneva, Boyana; Faestermann, Thomas; Famulok, Nicolai; Fimiani, Leticia; Gómez-Guzmán, José Manuel; Hain, Karin; Korschinek, Gunther; Hanzlik, Marianne; Merchel, Silke; Rugel, Georg

    2016-08-16

    Massive stars ([Formula: see text]), which terminate their evolution as core-collapse supernovae, are theoretically predicted to eject [Formula: see text] of the radioisotope (60)Fe (half-life 2.61 Ma). If such an event occurs sufficiently close to our solar system, traces of the supernova debris could be deposited on Earth. Herein, we report a time-resolved (60)Fe signal residing, at least partially, in a biogenic reservoir. Using accelerator mass spectrometry, this signal was found through the direct detection of live (60)Fe atoms contained within secondary iron oxides, among which are magnetofossils, the fossilized chains of magnetite crystals produced by magnetotactic bacteria. The magnetofossils were chemically extracted from two Pacific Ocean sediment drill cores. Our results show that the (60)Fe signal onset occurs around 2.6 Ma to 2.8 Ma, near the lower Pleistocene boundary, terminates around 1.7 Ma, and peaks at about 2.2 Ma.

  7. UNSATURATED ZONE CALCITE 813C EVIDENCE OF SOUTHERN NEVADA CLIMATES DURING THE PAST 9 MILLION YEARS

    SciTech Connect

    JOSEPH F. WHELAN AND RICHARD J. MOSCATI

    1998-01-26

    Yucca Mountain, Nevada, is presently the object of intense study as a potential permanent repository for the Nation's high-level radioactive wastes. The mountain consists of a thick sequence of volcanic tuffs in which the depth to the water table ranges from 500 to 700 meters below the land surface. This thick unsaturated zone (UZ), which would host the projected repository, coupled with the present-day arid to semi-arid environment, is considered a positive argument for the site. Evaluation of the site includes defining the relationship between climate variability, as the input function or driver of site- and regional-scale ground-water flow, and the possible transport and release of radionuclides. Secondary calcite and opal have been deposited in the UZ by meteoric waters that infiltrated through overlying soils and percolated through the tuffs. The oxygen isotopic composition ({delta}{sup 18}O values) of these minerals reflect contemporaneous meteoric waters and the {delta}{sup 13}C values reflect soil organic matter, and hence the resident plant community, at the time of infiltration (Whelan et al., 1994). Recent U/Pb age determinations of opal in these occurrences allows the {delta}{sup 13}C values of associated calcite to be used to reconstruct general climate variations during the past 9 M.y.

  8. Evidence for life on Earth before 3,800 million years ago.

    PubMed

    Mojzsis, S J; Arrhenius, G; McKeegan, K D; Harrison, T M; Nutman, A P; Friend, C R

    1996-11-07

    It is unknown when life first appeared on Earth. The earliest known microfossils (approximately 3,500 Myr before present) are structurally complex, and if it is assumed that the associated organisms required a long time to develop this degree of complexity, then the existence of life much earlier than this can be argued. But the known examples of crustal rocks older than 3,500 Myr have experienced intense metamorphism, which would have obliterated any fragile microfossils contained therein. It is therefore necessary to search for geochemical evidence of past biotic activity that has been preserved within minerals that are resistant to metamorphism. Here we report ion-microprobe measurements of the carbon-isotope composition of carbonaceous inclusions within grains of apatite (basic calcium phosphate) from the oldest known sediment sequences--a approximately 3,800-Myr-old banded iron formation from the Isua supracrustal belt, West Greenland, and a similar formation from the nearby Akilia island that is possibly older than 3,850 Myr. The carbon in the carbonaceous inclusions is isotopically light, indicative of biological activity; no known abiotic process can explain the data. Unless some unknown abiotic process exists which is able both to create such isotopically light carbon and then selectively incorporate it into apatite grains, our results provide evidence for the emergence of life on Earth by at least 3,800 Myr before present.

  9. 300 million years of basin evolution - the thermotectonic history of the Ukrainian Donbas Foldbelt

    NASA Astrophysics Data System (ADS)

    Spiegel, C.; Danisik, M.; Sachsenhofer, R.; Frisch, W.; Privalov, V.

    2009-04-01

    The Ukrainian-Russian Pripyat-Dniepr-Donets Basin is a large intracratonic rift structure formed during the Late Devonian. It is situated at the southern margin of the Precambrian East European Craton, adjacent to the Hercynian Tethyan belt in the Black Sea area and the Alpine Caucasus orogen. With a sediment thickness of more than 20 km, it is one of the deepest sedimentary basins on earth. The eastern part of the Pripyat-Dniepr-Donets Basin - called Donbas foldbelt - is strongly folded and inverted. Proposed models of basin evolution are often controversial and numerous issues are still a matter of speculation, particularly the erosion history and the timing of basin inversion. Basin inversion may have taken place during the Permian related to the Uralian orogeny, or in response to Alpine tectonics during the Late Cretaceous to Early Tertiary. We investigated the low-temperature thermal history of the Donbas Foldbelt and the adjacent Ukrainian shield by a combination of zircon fission track, apatite fission track and apatite (U-Th)/He thermochronology. Although apatite fission track ages of all sedimentary samples were reset shortly after deposition during the Carboniferous, we took advantage of the fact that samples contained kinetically variable apatites, which are sensitive to different temperatures. By using statistic-based component analysis incorporating physical properties of individual grains we identified several distinct age population, ranging from late Permian (~265 Ma) to the Late Cretaceous (70 Ma). We could thus constrain the thermal history of the Donbas Foldbelt and the adjacent basement during a ~300 Myr long time period. The Precambrian crystalline basement of the Ukrainian shield was affected by a Permo-Triassic thermal event associated with magmatic activity, which also strongly heated the sediments of the Donbas Foldbelt. The basement rocks cooled to near-surface conditions during the Early to Middle Triassic and since then was thermally stable. The basin margins started to cool during the Permo-Triassic whereas the central parts were residing or slowly cooling through the apatite partial annealing zone during the Jurassic and most of the Cretaceous and eventually cooled to near-surface conditions around the Cretaceous-Paleogene boundary. Our data show that Permian erosion was lower and Mesozoic erosion larger than generally assumed. Inversion and pop-up of the Donbas Foldbelt occurred in the Cretaceous and not in the Permian as previously thought. This is indicated by overall Cretaceous apatite fission track ages in the central parts of the basin.

  10. Million year old ice found under meter thick debris layer in Antarctica

    NASA Astrophysics Data System (ADS)

    Bibby, Theodore; Putkonen, Jaakko; Morgan, Daniel; Balco, Greg; Shuster, David L.

    2016-07-01

    Cosmogenic nuclide measurements associated with buried glacier ice in Ong Valley, in the Transantarctic Mountains, suggest the preservation of ancient ice. There are three glacial tills on the valley floor which have formed from the concentration of regolith contained within sublimating glacier ice. Two tills are less than 1 m thick and underlain by ice. Measurements of cosmogenic 10Be, 26Al, and 21Ne show that (i) the youngest buried ice unit and corresponding till are at least 11-13 ka, (ii) another ice unit and corresponding intermediate-age till are at least 1.1 Ma old under any circumstances and most likely older than 1.78 Ma, and (iii) the oldest till is at least 1.57 Ma and most likely greater than 2.63 Ma. These observations highlight the longevity of ice under thin debris layers and the potential to sample ancient ice for paleoclimate/paleoatmosphere information close to the present land surface.

  11. Impact of climate changes during the last 5 million years on groundwater in basement aquifers.

    PubMed

    Aquilina, Luc; Vergnaud-Ayraud, Virginie; Les Landes, Antoine Armandine; Pauwels, Hélène; Davy, Philippe; Pételet-Giraud, Emmanuelle; Labasque, Thierry; Roques, Clément; Chatton, Eliot; Bour, Olivier; Ben Maamar, Sarah; Dufresne, Alexis; Khaska, Mahmoud; Le Gal La Salle, Corinne; Barbecot, Florent

    2015-09-22

    Climate change is thought to have major effects on groundwater resources. There is however a limited knowledge of the impacts of past climate changes such as warm or glacial periods on groundwater although marine or glacial fluids may have circulated in basements during these periods. Geochemical investigations of groundwater at shallow depth (80-400 m) in the Armorican basement (western France) revealed three major phases of evolution: (1) Mio-Pliocene transgressions led to marine water introduction in the whole rock porosity through density and then diffusion processes, (2) intensive and rapid recharge after the glacial maximum down to several hundred meters depths, (3) a present-day regime of groundwater circulation limited to shallow depth. This work identifies important constraints regarding the mechanisms responsible for both marine and glacial fluid migrations and their preservation within a basement. It defines the first clear time scales of these processes and thus provides a unique case for understanding the effects of climate changes on hydrogeology in basements. It reveals that glacial water is supplied in significant amounts to deep aquifers even in permafrosted zones. It also emphasizes the vulnerability of modern groundwater hydrosystems to climate change as groundwater active aquifers is restricted to shallow depths.

  12. Places with Prime Contract Awards of $5 Million or More, Fiscal Year 1987.

    DTIC Science & Technology

    1987-01-01

    N 0~ N N~ ’-4 -4 P1 - , -- -4 N~ (’ 0 0 4 .4 -4 in c o c oocn cr- o o - o 0 00 0 N 0-1 0 " W wo w W(. 0 o N N C~f -4-,C,4 c 4 c - 0 ~~ ~ ( la C nC 0...0 . 0> P1 - (1, >- < LA00. 4 I - Z"- -Z "-L V) - wz.40~ Z. - -u = w c <A = 0~ WLA L - = OW LA V) c 4Z w OCLAt(/ CK <.Z LA c c him LU to F0 02W 4 OW...w m I-1- ... ..J 14 Li.)I. - cc Cd) D * P. 0L 1- ..) -j 40 OIL > 1- - 0 1-~ > " 1- Z0.)O mI 0-J l.’ I-. Mot,1 1-Il000 NCOON P1 -01-1f 0) a* Cmml. W0

  13. IMPRINT OF A 2 MILLION YEAR OLD SOURCE ON THE COSMIC-RAY ANISOTROPY

    SciTech Connect

    Savchenko, V.; Semikoz, D. V.; Kachelrieß, M.

    2015-08-20

    We study numerically the anisotropy of the cosmic-ray (CR) flux emitted by a single source calculating the trajectories of individual CRs. We show that the contribution of a single source to the observed anisotropy is determined solely by the fraction the source contributes to the total CR intensity, its age, and its distance and does not depend on the CR energy at late times. Therefore, the observation of a constant dipole anisotropy indicates that a single source dominates the CR flux in the corresponding energy range. A natural explanation for the plateau between 2–20 TeV observed in the CR anisotropy is thus the presence of a single, nearby source. For the source age of 2 Myr, as suggested by the explanation of the antiproton and positron data from PAMELA and AMS-02 through a local source, we determine the source distance as ∼200 pc. Combined with the contribution of the global CR sea calculated in the escape model, we can explain qualitatively the data for the dipole anisotropy. Our results suggest that the assumption of a smooth CR source distribution should be abandoned between ≃200 GeV and 1 PeV.

  14. Fifteen million years of evolution in the Oryza genus shows extensive gene family expansion.

    PubMed

    Jacquemin, Julie; Ammiraju, Jetty S S; Haberer, Georg; Billheimer, Dean D; Yu, Yeisoo; Liu, Liana C; Rivera, Luis F; Mayer, Klaus; Chen, Mingsheng; Wing, Rod A

    2014-04-01

    In analyzing gene families in the whole-genome sequences available for O. sativa (AA), O. glaberrima (AA), and O. brachyantha (FF), we observed large size expansions in the AA genomes compared to FF genomes for the super-families F-box and NB-ARC, and five additional families: the Aspartic proteases, BTB/POZ proteins (BTB), Glutaredoxins, Trypsin α-amylase inhibitor proteins, and Zf-Dof proteins. Their evolutionary dynamic was investigated to understand how and why such important size variations are observed between these closely related species. We show that expansions resulted from both amplification, largely by tandem duplications, and contraction by gene losses. For the F-box and NB-ARC gene families, the genes conserved in all species were under strong purifying selection while expanded orthologous genes were under more relaxed purifying selection. In F-box, NB-ARC, and BTB, the expanded groups were enriched in genes with little evidence of expression, in comparison with conserved groups. We also detected 87 loci under positive selection in the expanded groups. These results show that most of the duplicated copies in the expanded groups evolve neutrally after duplication because of functional redundancy but a fraction of these genes were preserved following neofunctionalization. Hence, the lineage-specific expansions observed between Oryza species were partly driven by directional selection.

  15. Atmospheric composition 1 million years ago from blue ice in the Allan Hills, Antarctica.

    PubMed

    Higgins, John A; Kurbatov, Andrei V; Spaulding, Nicole E; Brook, Ed; Introne, Douglas S; Chimiak, Laura M; Yan, Yuzhen; Mayewski, Paul A; Bender, Michael L

    2015-06-02

    Here, we present direct measurements of atmospheric composition and Antarctic climate from the mid-Pleistocene (∼1 Ma) from ice cores drilled in the Allan Hills blue ice area, Antarctica. The 1-Ma ice is dated from the deficit in (40)Ar relative to the modern atmosphere and is present as a stratigraphically disturbed 12-m section at the base of a 126-m ice core. The 1-Ma ice appears to represent most of the amplitude of contemporaneous climate cycles and CO2 and CH4 concentrations in the ice range from 221 to 277 ppm and 411 to 569 parts per billion (ppb), respectively. These concentrations, together with measured δD of the ice, are at the warm end of the field for glacial-interglacial cycles of the last 800 ky and span only about one-half of the range. The highest CO2 values in the 1-Ma ice fall within the range of interglacial values of the last 400 ka but are up to 7 ppm higher than any interglacial values between 450 and 800 ka. The lowest CO2 values are 30 ppm higher than during any glacial period between 450 and 800 ka. This study shows that the coupling of Antarctic temperature and atmospheric CO2 extended into the mid-Pleistocene and demonstrates the feasibility of discontinuously extending the current ice core record beyond 800 ka by shallow coring in Antarctic blue ice areas.

  16. Tracking Gradual Oxidation of Variably Altered MORB in the First Million Years

    NASA Astrophysics Data System (ADS)

    Wang, D.; Van der Voo, R.; Peacor, D. R.

    2002-05-01

    It is well established that titanomagnetite undergoes low temperature oxidation, but the time scale for this process is still poorly understood. A suite of five dredged ocean-floor basalt samples (cruise PHNX02), ranging in age between 200 and 800 ka, has been characterized in terms of maghemitization processes. The pillow fragments reveal discolored and altered zones along cracks, and subsamples have been studied across these fragments in a zone parallel to the outer pillow rims. This allows us to study the alteration without having to account for variable grain size. TEM studies of the discolored edges and the fresh, gray interior reveal that the latter have lower oxidation parameters (z ranging from 0.25 to 0.65) than the discolored zones where z exceeds 0.65 even for the youngest (200 ka) sample. The TEM (HOLZ-line) technique to determine z is preferred over the use of Curie temperatures, because the latter are clearly influenced by observed variations in Ti-content. Correlations between the z parameter and NRM (or Ms and Mrs) intensities are not straightforward, so that we cannot conclude that increased oxidation reduces magnetic intensities, as is commonly thought. We intend to explore whether the decrease in NRM with age up to some 20 Ma is possibly caused by other rock magnetic factors.

  17. Latitudinal signature of Earth's magnetic field variation over the last 5 million years

    NASA Astrophysics Data System (ADS)

    Harrison, Christopher G. A.

    2009-02-01

    In order to investigate the latitudinal effect of the geomagnetic field variation, a new data set consisting of virtual geomagnetic poles (VGPs) from all latitudes has been produced. Since the updated data set was limited to data with VGPs within 45° of the geographic poles, data from lava flows with low-latitude VGPs were added. More rigorous criteria were used to winnow the data. The data were divided into groups from different observation latitudes. In each group it was shown that the distribution of VGP latitudes could be described by a predominance of poles (average 82%) following a Fisher distribution with the rest following a distribution that would produce a uniform number of poles as a function of latitude. A distribution composed of two Fisher distributions also fit the data very well. For the case using a Fisher distribution plus a uniform distribution, the Fisher distribution changed such that the angular standard deviation (ASD) of VGPs from a set of observations taken at the equator is about 10° and the ASD at 60° observation latitude is about 19°. These results are similar to some results seeking to determine the ASD of VGPs as a function of observation latitude using other methods, which have been recently published, but there are also discrepancies. The results allow us to model inclination distributions as a function of observation latitude for comparison with data in which only the inclination is known, such as data from drill holes. It is shown that in order not to have doubt about the polarity of the inclination data, a drill hole has to be located at an absolute latitude greater than 27° for there to be less than a 5% error. This has major importance for the location of the "Mission to the MOHO" of the Integrated Ocean Drilling Program. The results also confirm that the sources of the nondipole field located in the outer core have to be more than twice as strong at high latitudes than at low latitudes so as to produce the observed increase in VGP scatter with observation latitude. The model of the secular variation proposed here is in no way a theory about how the secular variation happens, but it does allow those who wish to develop such a theory to have a model distribution with which to check their predictions.

  18. Traces of an ancient immune system – how an injured arthropod survived 465 million years ago

    PubMed Central

    Schoenemann, Brigitte; Clarkson, Euan N. K.; Høyberget, Magne

    2017-01-01

    This report of a severely injured trilobite from the Middle Ordovician (~465 Ma) accords with a number of similar observations of healed lesions observed in trilobites. The uniqueness of the specimen described here is that the character of the repair-mechanisms is reflected by the secondarily built structures, which form the new surface of the ruptured compound eye. Smooth, repaired areas inside the visual surface advert to a clotting principle, rather similar to those of today, and the way in which broken parts of the exoskeleton fused during restoration seem to simulate modern samples. The irregularity and variance of newly inserted visual units indicate the severity of the injury, which, most probably, was caused by a predatory attack, presumably by a cephalopod; these were most likely, the top predators of the Ordovician. Furthermore, the state of the moulted cephalon tells the dramatic struggle of an organism that lived in the Palaeozoic, to survive. In sum the specimen analysed here is evidence of an ancient clotting mechanism not dissimilar to those of today, rapidly preventing any exsanguination and the breakdown of osmoregulation of this marine arthropod. PMID:28074858

  19. 400 million years on six legs: on the origin and early evolution of Hexapoda.

    PubMed

    Grimaldi, David A

    2010-01-01

    Identifying the unambiguous sister group to the hexapods has been elusive. Traditional concepts include the Myriapoda (the Tracheata/Atelocerata hypothesis), but recent molecular studies consistently indicate it is the Crustacea, either in part or entirety (the Pancrustacea/Tetraconata hypothesis). The morphological evidence in support of Tracheata is reviewed, and most features are found to be ambiguous (i.e., losses, poorly known and surveyed structures, and probable convergences), though some appear to be synapomorphic, such as tentorial structure and the presence of styli and eversible vesicles. Other morphological features, particularly the structure of the eyes and nervous system, support Pancrustacea, as does consistent molecular evidence (which is reviewed and critiqued). Suggestions are made regarding hexapod-crustacean limb homologies. Relationships among basal (apterygote) hexapods are reviewed, and critical Paleozoic fossils are discussed. Despite the scarceness of Devonian hexapods, major lineages like Collembola and even dicondylic Insecta appeared in the Early Devonian; stem-group and putative Archaeognatha are known from the Carboniferous through Permian and the Late Devonian, respectively. Thus, the earliest divergences of hexapods were perhaps Late Silurian, which is considerably younger than several estimates made using molecular data.

  20. Metabolic dominance of bivalves predates brachiopod diversity decline by more than 150 million years

    PubMed Central

    Payne, Jonathan L.; Heim, Noel A.; Knope, Matthew L.; McClain, Craig R.

    2014-01-01

    Brachiopods and bivalves feed in similar ways and have occupied the same environments through geological time, but brachiopods were far more diverse and abundant in the Palaeozoic whereas bivalves dominate the post-Palaeozoic, suggesting a transition in ecological dominance 250 Ma. However, diversity and abundance data alone may not adequately describe key changes in ecosystem function, such as metabolic activity. Here, we use newly compiled body size data for 6066 genera of bivalves and brachiopods to calculate metabolic rates and revisit this question from the perspective of energy use, finding that bivalves already accounted for a larger share of metabolic activity in Palaeozoic oceans. We also find that the metabolic activity of bivalves has increased by more than two orders of magnitude over this interval, whereas brachiopod metabolic activity has declined by more than 50%. Consequently, the increase in bivalve energy metabolism must have occurred via the acquisition of new food resources rather than through the displacement of brachiopods. The canonical view of a mid-Phanerozoic transition from brachiopod to bivalve dominance results from a focus on taxonomic diversity and numerical abundance as measures of ecological importance. From a metabolic perspective, the oceans have always belonged to the clams. PMID:24671970

  1. Time-resolved 2-million-year-old supernova activity discovered in Earth's microfossil record

    NASA Astrophysics Data System (ADS)

    Ludwig, Peter; Bishop, Shawn; Egli, Ramon; Chernenko, Valentyna; Deneva, Boyana; Faestermann, Thomas; Famulok, Nicolai; Fimiani, Leticia; Gómez-Guzmán, José Manuel; Hain, Karin; Korschinek, Gunther; Hanzlik, Marianne; Merchel, Silke; Rugel, Georg

    2016-08-01

    Massive stars (M10MM≳10 M⊙), which terminate their evolution as core-collapse supernovae, are theoretically predicted to eject >10-5M>10-5M⊙ of the radioisotope 60Fe (half-life 2.61 Ma). If such an event occurs sufficiently close to our solar system, traces of the supernova debris could be deposited on Earth. Herein, we report a time-resolved 60Fe signal residing, at least partially, in a biogenic reservoir. Using accelerator mass spectrometry, this signal was found through the direct detection of live 60Fe atoms contained within secondary iron oxides, among which are magnetofossils, the fossilized chains of magnetite crystals produced by magnetotactic bacteria. The magnetofossils were chemically extracted from two Pacific Ocean sediment drill cores. Our results show that the 60Fe signal onset occurs around 2.6 Ma to 2.8 Ma, near the lower Pleistocene boundary, terminates around 1.7 Ma, and peaks at about 2.2 Ma.

  2. Early and Extended Helium Reionization over More Than 600 Million Years of Cosmic Time

    NASA Astrophysics Data System (ADS)

    Worseck, Gábor; Prochaska, J. Xavier; Hennawi, Joseph F.; McQuinn, Matthew

    2016-07-01

    We measure the effective optical depth of He ii Lyα absorption {τ }{eff,{He}{{II}}} at 2.3\\lt z\\lt 3.5 in 17 UV-transmitting quasars observed with UV spectrographs on the Hubble Space Telescope. The median {τ }{eff,{He}{{II}}} values increase gradually from 1.95 at z=2.7 to 5.17 at z=3.4, but with a strong sightline-to-sightline variance. Many ≃ 35 comoving Mpc regions of the z\\gt 3 intergalactic medium (IGM) remain transmissive ({τ }{eff,{He}{{II}}}\\lt 4), and the gradual trend with redshift appears consistent with density evolution of a fully reionized IGM. These modest optical depths imply average He ii fractions of {x}{He{{II}}}\\lt 0.01 and He ii ionizing photon mean free paths of ≃ 50 comoving Mpc at z≃ 3.4, thus requiring that a substantial volume of the helium in the universe was already doubly ionized at early times; this stands in conflict with current models of He ii reionization driven by luminous quasars. Along 10 sightlines we measure the coeval H i Lyα effective optical depths, allowing us to study the density dependence of {τ }{eff,{He}{{II}}} at z˜ 3. We establish that the dependence of {τ }{eff,{He}{{II}}} on increasing {τ }{eff,{{H}}{{I}}} is significantly shallower than expected from simple models of an IGM reionized in He ii. This requires higher He ii photoionization rates in overdense regions or underdense regions being not in photoionization equilibrium. Moreover, there are very large fluctuations in {τ }{eff,{He}{{II}}} at all {τ }{eff,{{H}}{{I}}} which greatly exceed the expectations from these simple models. These data present a distinct challenge to scenarios of He ii reionization—an IGM where He ii appears to be predominantly ionized at z≃ 3.4, and with a radiation field strength that may be correlated with the density field, but exhibits large fluctuations at all densities. Based on observations made with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with Program #11742. Archival HST data (#7575, 9350, 11528, 12178, 12249) were obtained from the Mikulski Archive for Space Telescopes (MAST). Several HST programs provided ancillary calibration data (#11860, 11895, 12414, 12423, 12716, 12775, 12870, 13108). Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and NASA; it was made possible by the generous financial support of the W.M. Keck Foundation. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under program IDs 166.A-0106, 071.A-0066 and 083.A-0421.

  3. Surprising flexibility in a conserved Hox transcription factor over 550 million years of evolution

    PubMed Central

    Heffer, Alison; Shultz, Jeffrey W.; Pick, Leslie

    2010-01-01

    Although metazoan body plans are remarkably diverse, the structure and function of many embryonic regulatory genes are conserved because large changes would be detrimental to development. However, the fushi tarazu (ftz) gene has changed dramatically during arthropod evolution from Hox-like to a pair-rule segmentation gene in Drosophila. Changes in both expression and protein sequence contributed to this new function: ftz expression switched from Hox-like to stripes and changes in Ftz cofactor interaction motifs led to loss of homeotic and gain of segmentation potential. Here, we reconstructed ftz changes in a rigorous phylogenetic context. We found that ftz did not simply switch from Hox-like to segmentation function; rather, ftz is remarkably labile, having undergone multiple changes in sequence and expression. The segmentation LXXLL motif was stably acquired in holometabolous insects after the appearance of striped expression in early insect lineages. The homeotic YPWM motif independently degenerated multiple times. These “degen-YPWMs” showed varying degrees of homeotic potential when expressed in Drosophila, suggesting variable loss of Hox function in different arthropods. Finally, the intensity of ftz Hox-like expression decreased to marginal levels in some crustaceans. We propose that decreased expression levels permitted ftz variants to arise and persist in populations without disadvantaging organismal development. This process, in turn, allowed evolutionary transitions in protein function, as weakly expressed “hopeful gene variants” were coopted into alternative developmental pathways. Our findings show that variation of a pleiotropic transcription factor is more extensive than previously imagined, suggesting that evolutionary plasticity may be widespread among regulatory genes. PMID:20921393

  4. Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years.

    PubMed

    Crampton, James S; Cody, Rosie D; Levy, Richard; Harwood, David; McKay, Robert; Naish, Tim R

    2016-06-21

    It is not clear how Southern Ocean phytoplankton communities, which form the base of the marine food web and are a crucial element of the carbon cycle, respond to major environmental disturbance. Here, we use a new model ensemble reconstruction of diatom speciation and extinction rates to examine phytoplankton response to climate change in the southern high latitudes over the past 15 My. We identify five major episodes of species turnover (origination rate plus extinction rate) that were coincident with times of cooling in southern high-latitude climate, Antarctic ice sheet growth across the continental shelves, and associated seasonal sea-ice expansion across the Southern Ocean. We infer that past plankton turnover occurred when a warmer-than-present climate was terminated by a major period of glaciation that resulted in loss of open-ocean habitat south of the polar front, driving non-ice adapted diatoms to regional or global extinction. These findings suggest, therefore, that Southern Ocean phytoplankton communities tolerate "baseline" variability on glacial-interglacial timescales but are sensitive to large-scale changes in mean climate state driven by a combination of long-period variations in orbital forcing and atmospheric carbon dioxide perturbations.

  5. Seven 365-Million-Year-Old Trilobites Moulting within a Nautiloid Conch

    NASA Astrophysics Data System (ADS)

    Zong, Rui-Wen; Fan, Ruo-Ying; Gong, Yi-Ming

    2016-10-01

    A nautiloid conch containing many disarticulated exoskeletons of Omegops cornelius (Phacopidae, Trilobita) was found in the Upper Devonian Hongguleleng Formation of the northwestern margin of the Junggar Basin, NW China. The similar number of cephala, thoraces and pygidia, unbroken thoraces, explicit exuviae, and lack of other macrofossils in the conch, indicate that at least seven individual trilobites had moulted within the nautiloid living chamber, using the vacant chamber of a dead nautiloid as a communal place for ecdysis. This exuvial strategy manifests cryptic behaviour of trilobites, which may have resulted from the adaptive evolution induced by powerful predation pressure, unstable marine environments, and competition pressure of organisms occupying the same ecological niche in the Devonian period. The unusual presence of several trilobites moulting within a nautiloid conch is possibly associated with social behaviours in face of a serious crisis. New materials in this study open a window for understanding the survival strategy of marine benthic organisms, especially predator-prey interactions and the behavioural ecology of trilobites in the middle Palaeozoic.

  6. New 1.5 million-year-old Homo erectus maxilla from Sangiran (Central Java, Indonesia).

    PubMed

    Zaim, Yahdi; Ciochon, Russell L; Polanski, Joshua M; Grine, Frederick E; Bettis, E Arthur; Rizal, Yan; Franciscus, Robert G; Larick, Roy R; Heizler, Matthew; Aswan; Eaves, K Lindsay; Marsh, Hannah E

    2011-10-01

    Sangiran (Solo Basin, Central Java, Indonesia) is the singular Homo erectus fossil locale for Early Pleistocene Southeast Asia. Sangiran is the source for more than 80 specimens in deposits with (40)Ar/(39)Ar ages of 1.51-0.9 Ma. In April 2001, we recovered a H. erectus left maxilla fragment (preserving P(3)- M(2)) from the Sangiran site of Bapang. The find spot lies at the base of the Bapang Formation type section in cemented gravelly sands traditionally called the Grenzbank Zone. Two meters above the find spot, pumice hornblende has produced an (40)Ar/(39)Ar age of 1.51 ± 0.08 Ma. With the addition of Bpg 2001.04, Sangiran now has five H. erectus maxillae. We compare the new maxilla with homologs representing Sangiran H. erectus, Zhoukoudian H. erectus, Western H. erectus (pooled African and Georgian specimens), and Homo habilis. Greatest contrast is with the Zhoukoudian maxillae, which appear to exhibit a derived pattern of premolar-molar relationships compared to Western and Sangiran H. erectus. The dental patterns suggest distinct demic origins for the earlier H. erectus populations represented at Sangiran and the later population represented at Zhoukoudian. These two east Asian populations, separated by 5000 km and nearly 800 k.yr., may have had separate origins from different African/west Eurasian populations.

  7. Conservation of transcription factor binding specificities across 600 million years of bilateria evolution

    PubMed Central

    Nitta, Kazuhiro R; Jolma, Arttu; Yin, Yimeng; Morgunova, Ekaterina; Kivioja, Teemu; Akhtar, Junaid; Hens, Korneel; Toivonen, Jarkko; Deplancke, Bart; Furlong, Eileen E M; Taipale, Jussi

    2015-01-01

    Divergent morphology of species has largely been ascribed to genetic differences in the tissue-specific expression of proteins, which could be achieved by divergence in cis-regulatory elements or by altering the binding specificity of transcription factors (TFs). The relative importance of the latter has been difficult to assess, as previous systematic analyses of TF binding specificity have been performed using different methods in different species. To address this, we determined the binding specificities of 242 Drosophila TFs, and compared them to human and mouse data. This analysis revealed that TF binding specificities are highly conserved between Drosophila and mammals, and that for orthologous TFs, the similarity extends even to the level of very subtle dinucleotide binding preferences. The few human TFs with divergent specificities function in cell types not found in fruit flies, suggesting that evolution of TF specificities contributes to emergence of novel types of differentiated cells. DOI: http://dx.doi.org/10.7554/eLife.04837.001 PMID:25779349

  8. Comment on "Bilaterian burrows and grazing behavior at >585 million years ago".

    PubMed

    Gaucher, Claudio; Poiré, Daniel G; Bossi, Jorge; Bettucci, Leda Sánchez; Beri, Ángeles

    2013-02-22

    Pecoits et al. (Reports, 29 June 2012, p. 1693) describe bilaterian trace fossils and assign them an Ediacaran age based on the age of a granite interpreted as intrusive. We argue that the granite is not intrusive but in fact represents the basement of the sedimentary succession. Moreover, we show that identical trace fossils occur in nearby Carboniferous-Permian glacigenic rocks.

  9. Response to comment on "Bilaterian burrows and grazing behavior at >585 million years ago".

    PubMed

    Pecoits, Ernesto; Konhauser, Kurt O; Aubet, Natalie R; Heaman, Larry M; Veroslavsky, Gerardo; Stern, Richard; Gingras, Murray K

    2013-02-22

    Gaucher et al. suggest that their field observations and petrographic analysis of one thin section do not support an Ediacaran age for the trace fossils-bearing strata of the Tacuarí Formation. We have strengthened our conclusion of an Ediacaran age for the Tacuarí Formation based on reassessment of new and previously presented field and petrographic evidence.

  10. Oxygen and Hydrogen Stable Isotope Composition of Eocene ( ~45 million year old) Fossil Tree Cellulose

    NASA Astrophysics Data System (ADS)

    Jahren, H.

    2001-05-01

    I report on \\delta18O and \\deltaD values gained from unusually old tree fossils, collected on Axel Heiberg Island of the Canadian High Arctic. A variety of workers have measured the δ ^{18}O value of cellulose and the δ D value of cellulose nitrate isolated from modern trees and compared it to various environmental parameters (esp. Epstein et al., 1977: 14 tree species sampled at 16 sites ranging from 18 \\deg to 62 \\deg North latitude; \\delta18O of cellulose ranged from +20 to +33 \\permil; \\deltaD of cellulose nitrate ranged from -181 to +18). To date the paleoenvironmental interpretations resulting from these studies have been restricted to application in recent and Quaternary earth history due to the lack of sufficiently preserved cellulose and tree ring structure in older tree fossils. An exception to this generalization are the middle Eocene (\\sim45 my old) fossil forests of Axel Heiberg Island, which contain abundant stumps, branches, twigs, cones and leaves of Metasequoia trees in exquisite preservational condition. These deciduous trees grew at a paleolatitude of 80 ° North, and endured prolonged periods of continuous daylight in the summer and continuous darkness in the winter, making the ecosystem completely unlike any forest community existing today. Fossil wood samples from the site have been slightly compressed, but otherwise exhibit minimal alteration: %C and % cellulose (by mass) are similar to modern Metasequoia wood. δ ^{18}O analyses on cellulose isolated from 14 fossil individuals has yielded the following results: range = +17 to +20 ‰ ; mean = +19 ‰ ; variability within an individual = 0.5 to 1.0 ‰ . In presentation, I will complement these results with δ D determinations on cellulose nitrate isolated from the same individuals, as well as from small plants presently growing in the arctic. I will also discuss the surprising result that Axel Heiberg fossil trees appear to have stable isotope composition as low or lower than trees growing in the most extremely cold environments found on earth today, in contrast to the fact that the middle Eocene has been conceived by some as the maximum of Mesozoic-early Cenozoic global tropicality, partially based upon the presence of abundant vegetation at high latitudes.

  11. Southern Ocean phytoplankton turnover in response to stepwise Antarctic cooling over the past 15 million years

    NASA Astrophysics Data System (ADS)

    Crampton, James S.; Cody, Rosie D.; Levy, Richard; Harwood, David; McKay, Robert; Naish, Tim R.

    2016-06-01

    It is not clear how Southern Ocean phytoplankton communities, which form the base of the marine food web and are a crucial element of the carbon cycle, respond to major environmental disturbance. Here, we use a new model ensemble reconstruction of diatom speciation and extinction rates to examine phytoplankton response to climate change in the southern high latitudes over the past 15 My. We identify five major episodes of species turnover (origination rate plus extinction rate) that were coincident with times of cooling in southern high-latitude climate, Antarctic ice sheet growth across the continental shelves, and associated seasonal sea-ice expansion across the Southern Ocean. We infer that past plankton turnover occurred when a warmer-than-present climate was terminated by a major period of glaciation that resulted in loss of open-ocean habitat south of the polar front, driving non-ice adapted diatoms to regional or global extinction. These findings suggest, therefore, that Southern Ocean phytoplankton communities tolerate “baseline” variability on glacial-interglacial timescales but are sensitive to large-scale changes in mean climate state driven by a combination of long-period variations in orbital forcing and atmospheric carbon dioxide perturbations.

  12. Reconstructing the anatomy of the 42-million-year-old fossil † Mengea tertiaria (Insecta, Strepsiptera)

    NASA Astrophysics Data System (ADS)

    Pohl, Hans; Wipfler, Benjamin; Grimaldi, David; Beckmann, Felix; Beutel, Rolf G.

    2010-09-01

    Fossilization in amber is unique in preserving specimens with microscopic fidelity; however, arthropod inclusions are rarely examined beyond the exoskeleton as this requires destructive sampling when traditional techniques are used. We report the first complete, digital 3D, non-destructive reconstruction of the anatomy of an insect fossil, a specimen of † Mengea tertiaria embedded in a 42-Ma Baltic amber. This was made possible using Synchrotron μ-CT. The species belongs to the stem group of the phylogenetically enigmatic and extremely specialized Strepsiptera. Most internal structures of the fossil are preserved, but small parts of the lumen had decayed due to incomplete infiltration of the resin. Data on internal organs provided additional information for resolving phylogenetic relationships. A sister group relationship between † Mengea and all extant lineages of the group was confirmed with characters previously not accessible. The newly gained information also yielded some insights in the biology of † Mengea and the early evolutionary history of Strepsiptera. The technique has a tremendous potential for a more accurate interpretation of diverse fossil arthropods preserved in ambers from 130 Ma to the present.

  13. One hundred million year old ergot: psychotropic compounds in the Cretaceous?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A fungal sclerotium similar to sclerotia of the genus Claviceps, commonly known as ergot, was found infecting a grass kernel in Early Cretaceous Myanmar amber. This represents the first fossil record of ergot dating as far back as the Cretaceous period. The fungus, described as Palaeoclaviceps para...

  14. Almost a spider: a 305-million-year-old fossil arachnid and spider origins.

    PubMed

    Garwood, Russell J; Dunlop, Jason A; Selden, Paul A; Spencer, Alan R T; Atwood, Robert C; Vo, Nghia T; Drakopoulos, Michael

    2016-03-30

    Spiders are an important animal group, with a long history. Details of their origins remain limited, with little knowledge of their stem group, and no insights into the sequence of character acquisition during spider evolution. We describe a new fossil arachnid, Idmonarachne brasierigen. et sp. nov. from the Late Carboniferous (Stephanian,ca 305-299 Ma) of Montceau-les-Mines, France. It is three-dimensionally preserved within a siderite concretion, allowing both laboratory- and synchrotron-based phase-contrast computed tomography reconstruction. The latter is a first for siderite-hosted fossils and has allowed us to investigate fine anatomical details. Although distinctly spider-like in habitus, this remarkable fossil lacks a key diagnostic character of Araneae: spinnerets on the underside of the opisthosoma. It also lacks a flagelliform telson found in the recently recognized, spider-related, Devonian-Permian Uraraneida. Cladistic analysis resolves our new fossil as sister group to the spiders: the spider stem-group comprises the uraraneids and I. brasieri While we are unable to demonstrate the presence of spigots in this fossil, the recovered phylogeny suggests the earliest character to evolve on the spider stem-group is the secretion of silk. This would have been followed by the loss of a flagelliform telson, and then the ability to spin silk using spinnerets. This last innovation defines the true spiders, significantly post-dates the origins of silk, and may be a key to the group's success. The Montceau-les-Mines locality has previously yielded a mesothele spider (with spinnerets). Evidently, Late Palaeozoic spiders lived alongside Palaeozoic arachnid grades which approached the spider condition, but did not express the full suite of crown-group autapomorphies.

  15. Changing sources of nutrients during four million years of ecosystem development

    NASA Astrophysics Data System (ADS)

    Chadwick, O. A.; Derry, L. A.; Vitousek, P. M.; Huebert, B. J.; Hedin, L. O.

    1999-02-01

    As soils develop in humid environments, rock-derived elements are gradually lost, and under constant conditions it seems that ecosystems should reach a state of profound and irreversible nutrient depletion. We show here that inputs of elements from the atmosphere can sustain the productivity of Hawaiian rainforests on highly weathered soils. Cations are supplied in marine aerosols and phosphorus is deposited in dust from central Asia, which is over 6,000km away.

  16. A 120 million years record of magmatism and crustal melting in the Kohistan Batholith

    NASA Astrophysics Data System (ADS)

    Schaltegger, U.; Frank, M.; Burg, J.-P.

    2003-04-01

    The Kohistan Arc Complex (KAC) in the Pakistani Himalaya is a volcanic arc terrane with a mantle-crust transition at its bottom and upper crustal volcano-sedimentary sequences above. The KAC features arc-type intrusives with oldest ages of c. 100 Ma, and a huge intrusion of gabbronorite at 85 Ma emplaced during a stage of intra-arc rifting (Schaltegger et al. 2002, Terra Nova 14, 461-468). The rift zone may have evolved into an intra-arc (or back-arc?) basin that persisted and remained marine until the Eocene (c. 50 Ma) i.e. after docking of the KAC against the Karakoram terrane in the north, which is reputed to be older than 75 Ma. The main part of the KAC is comprised of tonalites, diorites, granodiorites and granites that form the so-called Kohistan Batholith. U-Pb and Hf isotopic determinations of zircon from some of these plutons reveal the existence of a 154.0 +- 0.6 Ma old tonalite (compared to the Rb-Sr isochron age of 102 +- 12 Ma of Petterson &Windley, 1985) with an extremely high initial epsilon Hf value of +21. This rock intrudes volcanic units containing pillow basalts. It is thus tentatively interpreted as a tonalite produced by melting of oceanic lithosphere that has been melt-depleted during an ancient melting event. Other plutons are dated at 50 and 30 Ma. With an epsilon Hf around +10, they represent melting of an island-arc to MORB-type source. The 30 Ma-old leucogranite at the Indus confluence contains zircons with a 560 Ma inheritance, which is coupled to a lower epsilon Hf of +3-4, beside newly crystallized grains of 30 Ma with epsilon Hf=10. The Hf isotopes thus do not reveal any systematic change of the source composition with time, as it has been inferred from Sr and Nd isotopes. The Kohistan Batholith containing magmatic remnants of a pre-arc oceanic crust is thus demonstrated to be poly-episodic and composite. The magmatism, including 30 Ma old leucogranites, is derived from depleted mantle sources and does not contain detectable traces of melting of underplated Indian continental crust. Closure of the intra-/back-arc basin, and crustal thickening along the Dir Fault might be responsible for partial melting in the lower arc crust since the heat source cannot be the incoming, cold Indian lithosphere.

  17. Accretion rate of extraterrestrial matter: Iridium deposited over the last 70 million years

    NASA Technical Reports Server (NTRS)

    Kyte, Frank T.

    1988-01-01

    In order to quantify the accretion rate of extraterrestrial matter during the Cenozoic, Ir concentrations were measured in a continuous series of 450 samples across most of the length of piston core LL44-GPC3. LL44-GPC3 is a 25-meter-long, large-diameter piston core of abyssal clay from the central North Pacific. This core contains a nearly continuous record of sedimentation over the last 70 Ma, as this site migrated from a region near the Equator in the late Cretaceous to its present position north of Hawaii. The first-cut survey across the core is nearing completion, and all of the conclusions of the earlier study, in which was reported the concentrations of Ir, Co, and Sb across 9 meters of this core, remain unchanged. The only strongly enhanced Ir concentrations occur at the Cretaceous-Tertiary (K-T) boundary and outside the K-T boundary Ir correlates well with Co, a terrestrial element which is largely present in hydrogenous ferromanganese oxide precipitates from seawater. Concentrations of both elements appear to be inversely correlated with the sedimentation rate. Although the K-T Ir anomaly is unique in magnitude in this core, there are several small bumps in the Ir profile which may reflect smaller accretionary events. The most promising Ir enhancement was observed in a 30 cm section approximately 1 m below the K-T boundary. Preliminary data suggest deposition of an excess across this interval at a time estimate to be approximate 1 Ma before the K-T impact event, but there is insufficient evidence at present to prove that this reflects enhanced accretion of extraterrestrial matter. A detailed model is being prepared of the chemical record of sedimentation in this core using a combined database of 39 elements in approximately 450 samples across the Cenozoic. Preliminary working model indicates that the only sedimentary sources which contribute significantly to the Ir budget in this core are the hydrogenous precipitates and extraterrestrial particulates.

  18. Filling a 30 Million Year Gap: Radioisotopic Age Constraints for the Late Triassic Timescale

    NASA Astrophysics Data System (ADS)

    Irmis, R. B.; Mundil, R.

    2011-12-01

    The Triassic Period records a critical interval of Phanerozoic Earth history, including major paleoenvironmental changes in a greenhouse world, recovery from one mass extinction and the onset of another, and the origin of modern terrestrial ecosystems. Recent efforts have been instrumental in calibrating the timing of these events by producing numerous high resolution radioisotopic ages from Early and Middle Triassic marine strata that facilitate building of a robust 20 Ma chronostratigraphic framework. This contrasts starkly with the Late Triassic (Carnian, Norian, and Rhaetian stages), where ~30 Ma of the timescale is virtually uncalibrated by high-resolution radioisotopic data. This is the only interval of such long duration in the Mesozoic or Cenozoic that remains so poorly constrained by reliable absolute ages, despite the occurrence of major events such as the origin and early diversification of dinosaurs, major reef building episodes in marine ecosystems, key paleoenvironmental changes (e.g., Carnian Pluvial Event), and large extraterrestrial bolide impacts (e.g., Manicouagan). An additional challenge is that the biostratigraphically-defined marine timescale cannot be applied globally, so that other areas (e.g., New Zealand) have independent timescales that cannot be confidently correlated to classic Laurasian sections. All of these problems preclude formulating robust first-order hypotheses about the Late Triassic world. We present new CA-TIMS U-Pb zircon data from volcaniclastic units within both marine and terrestrial strata that aim at calibrating the timescale itself and as a result constrain the timing of some of these major events in Earth history. Several preliminary ages support the hypothesis that the Norian Stage was very long, ~20 Ma. Our new data from marine sequences in New Zealand demonstrate that the timescale divisions there do not correlate directly with biostratigraphic boundaries in the Tethys; specifically, the Ladinian-Carnian boundary is somewhere within the Kaihikuan biozone, and the lower Otamitan biozone is correlative with the mid-Norian. Our new data from the terrestrial Chinle Formation in the southwestern US demonstrate that all of this formation is Norian in age or later, younger than South American sequences it had previously been correlated with. This supports the hypothesis that the rise of dinosaurs was diachronous, occurring later in North America than in Argentina and Brazil. These new ages also constrain a major faunal turnover event in the middle Chinle Fm to the mid-Norian, close in age to the Manicouagan impact event. Correlation and calibration of these major events will be further strengthened by the unambiguous superposition provided by core samples, such as the forthcoming Colorado Plateau Coring Project.

  19. A unique coral biomineralization pattern has resisted 40 million years of major ocean chemistry change

    NASA Astrophysics Data System (ADS)

    Stolarski, Jarosław; Bosellini, Francesca R.; Wallace, Carden C.; Gothmann, Anne M.; Mazur, Maciej; Domart-Coulon, Isabelle; Gutner-Hoch, Eldad; Neuser, Rolf D.; Levy, Oren; Shemesh, Aldo; Meibom, Anders

    2016-06-01

    Today coral reefs are threatened by changes to seawater conditions associated with rapid anthropogenic global climate change. Yet, since the Cenozoic, these organisms have experienced major fluctuations in atmospheric CO2 levels (from greenhouse conditions of high pCO2 in the Eocene to low pCO2 ice-house conditions in the Oligocene-Miocene) and a dramatically changing ocean Mg/Ca ratio. Here we show that the most diverse, widespread, and abundant reef-building coral genus Acropora (20 morphological groups and 150 living species) has not only survived these environmental changes, but has maintained its distinct skeletal biomineralization pattern for at least 40 My: Well-preserved fossil Acropora skeletons from the Eocene, Oligocene, and Miocene show ultra-structures indistinguishable from those of extant representatives of the genus and their aragonitic skeleton Mg/Ca ratios trace the inferred ocean Mg/Ca ratio precisely since the Eocene. Therefore, among marine biogenic carbonate fossils, well-preserved acroporid skeletons represent material with very high potential for reconstruction of ancient ocean chemistry.

  20. A unique coral biomineralization pattern has resisted 40 million years of major ocean chemistry change.

    PubMed

    Stolarski, Jarosław; Bosellini, Francesca R; Wallace, Carden C; Gothmann, Anne M; Mazur, Maciej; Domart-Coulon, Isabelle; Gutner-Hoch, Eldad; Neuser, Rolf D; Levy, Oren; Shemesh, Aldo; Meibom, Anders

    2016-06-15

    Today coral reefs are threatened by changes to seawater conditions associated with rapid anthropogenic global climate change. Yet, since the Cenozoic, these organisms have experienced major fluctuations in atmospheric CO2 levels (from greenhouse conditions of high pCO2 in the Eocene to low pCO2 ice-house conditions in the Oligocene-Miocene) and a dramatically changing ocean Mg/Ca ratio. Here we show that the most diverse, widespread, and abundant reef-building coral genus Acropora (20 morphological groups and 150 living species) has not only survived these environmental changes, but has maintained its distinct skeletal biomineralization pattern for at least 40 My: Well-preserved fossil Acropora skeletons from the Eocene, Oligocene, and Miocene show ultra-structures indistinguishable from those of extant representatives of the genus and their aragonitic skeleton Mg/Ca ratios trace the inferred ocean Mg/Ca ratio precisely since the Eocene. Therefore, among marine biogenic carbonate fossils, well-preserved acroporid skeletons represent material with very high potential for reconstruction of ancient ocean chemistry.

  1. Porcine relaxin, a 500 million-year-old hormone? the tunicate Ciona intestinalis has porcine relaxin.

    PubMed

    Georges, D; Schwabe, C

    1999-07-01

    The fossil record of tunicates reaches back to the upper Cambrian period. Ascidians have mobile, tadpole-like juvenile forms with a notochord, which inspired the classification of tunicates as Urochordata, i.e., predecessors of vertebrates. The genome of the tunicate Ciona intestinalis contains a relaxin coding region that is organized like a mammalian gene, i.e., signal peptide, B-chain domain, connecting peptide domain, followed by the A-chain domain with a stop codon after cysteine A-22. RNA-derived cDNA encodes a relaxin that is identical to the circulating form of the porcine hormone. In contrast to the porcine gene, the ascidian gene has no intron in the C-peptide domain, and in that respect is similar to the bombyxin gene of the silkworm. During the spawning period, only enough relaxin could be extracted and isolated from gonads of C. intestinalis for a partial sequence analysis. Remarkable as it may be, these findings suggest that relaxin is identical in pigs, whales, and the tunicate C. intestinalis.

  2. A reconstruction of temperature, ice volume and atmospheric CO2 over the past 40 million years

    NASA Astrophysics Data System (ADS)

    Vutukuri, H. R.

    2012-02-01

    The central theme of this thesis is exploiting the directed self-assembly of both isotropic and anisotropic colloidal particles to achieve the fabrication of one-, two-, and three-dimensional complex colloidal structures using external electric fields and/or a simple in situ thermal annealing method. Colloids are typically defined as objects having at least one dimension in the size range of a few nanometers to several micrometers that form a dispersed phase when suspended in a continuum phase. As a result of Brownian motion, the colloidal particles are able to explore configurational space, and eventually reach the equilibrium configuration that minimizes the free energy. An important feature of the colloidal particles is the possibility of controlling the size, shape, and composition. The assembly of colloidal particles has long been a rich and continuously growing area of materials science, with great potential for a broad range of applications including electronics, optics, and biotechnology. Within this field, the bulk of the research has been devoted to studying the assembly of isotropic spherical particles. Recently, there has been growing interest in the design of more complex structures to see how such a change in microstructure could influence certain material properties, especially optical properties, but also to answer the demand for more realistic model systems for molecular analogues. In this thesis, we used external electric fields to impart anisotropy into systems consisting of both isotropic and an-isotropic particles. If there is a mismatch in permittivity between the particles and the suspending medium, the colloids acquire an induced dipole moment. A major advantage of this approach is that the interactions are tunable and fully reversible. Moreover, a large number of parameters can be used to control and tune particle interactions and subsequent self-assembly in AC electric fields, including field strength and frequency, particle shape, particle and solvent dielectric properties. Interestingly, the relatively simple anisotropic dipolar interaction already gives rise to several new phases in a uniaxial field. We developed methods to produce model systems that are essentially colloidal analogues of polymer chains in all three stiffness regimes that can be observed on a single particle level, even in concentrated systems without using molecular tracers. Moreover, we obtained control over the length, and the flexibility of the bead chains. We exploited our simple thermal sintering method further for bonding polymeric colloidal particles after they have been assembled into various three-dimensional structures. Next, we discussed the generality of our method by implementing this method to close and non-close packed structures. We used our thermal annealing method to synthesize more complex shape particles such as rhombic dodecahedron particles and also we discuss the stability of the particles. We controlled the lateral position of the strings of particles with micrometer-scale precision by a combination of structured wall and electric dipoles. We investigated the self-assembly of gold nano-sheets as a function of salt in electric fields. Finally, we studied the effect of external electric fields on the phase behavior of sharp-edged colloidal cubes using optical microscopy and Monte Carlo simulations.

  3. The First 40 Million Years of Circumstellar Disk Evolution: The Signature of Terrestrial Planet Formation

    NASA Astrophysics Data System (ADS)

    Meng, Huan Y. A.; Rieke, George H.; Su, Kate Y. L.; Gáspár, András

    2017-02-01

    We characterize the first 40 Myr of evolution of circumstellar disks through a unified study of the infrared properties of members of young clusters and associations with ages from 2 Myr up to ∼40 Myr: NGC 1333, NGC 1960, NGC 2232, NGC 2244, NGC 2362, NGC 2547, IC 348, IC 2395, IC 4665, Chamaeleon I, Orion OB1a and OB1b, Taurus, the β Pictoris Moving Group, ρ Ophiuchi, and the associations of Argus, Carina, Columba, Scorpius–Centaurus, and Tucana–Horologium. Our work features: (1) a filtering technique to flag noisy backgrounds; (2) a method based on the probability distribution of deflections, P(D), to obtain statistically valid photometry for faint sources; and (3) use of the evolutionary trend of transitional disks to constrain the overall behavior of bright disks. We find that the fraction of disks three or more times brighter than the stellar photospheres at 24 μm decays relatively slowly initially and then much more rapidly by ∼10 Myr. However, there is a continuing component until ∼35 Myr, probably due primarily to massive clouds of debris generated in giant impacts during the oligarchic/chaotic growth phases of terrestrial planets. If the contribution from primordial disks is excluded, the evolution of the incidence of these oligarchic/chaotic debris disks can be described empirically by a log-normal function with the peak at 12–20 Myr, including ∼13% of the original population, and with a post-peak mean duration of 10–20 Myr.

  4. Atmospheric composition 1 million years ago from blue ice in the Allan Hills, Antarctica

    PubMed Central

    Higgins, John A.; Kurbatov, Andrei V.; Spaulding, Nicole E.; Brook, Ed; Introne, Douglas S.; Chimiak, Laura M.; Yan, Yuzhen; Mayewski, Paul A.; Bender, Michael L.

    2015-01-01

    Here, we present direct measurements of atmospheric composition and Antarctic climate from the mid-Pleistocene (∼1 Ma) from ice cores drilled in the Allan Hills blue ice area, Antarctica. The 1-Ma ice is dated from the deficit in 40Ar relative to the modern atmosphere and is present as a stratigraphically disturbed 12-m section at the base of a 126-m ice core. The 1-Ma ice appears to represent most of the amplitude of contemporaneous climate cycles and CO2 and CH4 concentrations in the ice range from 221 to 277 ppm and 411 to 569 parts per billion (ppb), respectively. These concentrations, together with measured δD of the ice, are at the warm end of the field for glacial–interglacial cycles of the last 800 ky and span only about one-half of the range. The highest CO2 values in the 1-Ma ice fall within the range of interglacial values of the last 400 ka but are up to 7 ppm higher than any interglacial values between 450 and 800 ka. The lowest CO2 values are 30 ppm higher than during any glacial period between 450 and 800 ka. This study shows that the coupling of Antarctic temperature and atmospheric CO2 extended into the mid-Pleistocene and demonstrates the feasibility of discontinuously extending the current ice core record beyond 800 ka by shallow coring in Antarctic blue ice areas. PMID:25964367

  5. Maintenance of a Protein Structure in the Dynamic Evolution of TIMPs over 600 Million Years

    PubMed Central

    Nicosia, Aldo; Maggio, Teresa; Costa, Salvatore; Salamone, Monica; Tagliavia, Marcello; Mazzola, Salvatore; Gianguzza, Fabrizio; Cuttitta, Angela

    2016-01-01

    Deciphering the events leading to protein evolution represents a challenge, especially for protein families showing complex evolutionary history. Among them, TIMPs represent an ancient eukaryotic protein family widely distributed in the animal kingdom. They are known to control the turnover of the extracellular matrix and are considered to arise early during metazoan evolution, arguably tuning essential features of tissue and epithelial organization. To probe the structure and molecular evolution of TIMPs within metazoans, we report the mining and structural characterization of a large data set of TIMPs over approximately 600 Myr. The TIMPs repertoire was explored starting from the Cnidaria phylum, coeval with the origins of connective tissue, to great apes and humans. Despite dramatic sequence differences compared with highest metazoans, the ancestral proteins displayed the canonical TIMP fold. Only small structural changes, represented by an α-helix located in the N-domain, have occurred over the evolution. Both the occurrence of such secondary structure elements and the relative solvent accessibility of the corresponding residues in the three-dimensional structures raises the possibility that these sites represent unconserved element prone to accept variations. PMID:26957029

  6. Impact of climate changes during the last 5 million years on groundwater in basement aquifers

    PubMed Central

    Aquilina, Luc; Vergnaud-Ayraud, Virginie; Les Landes, Antoine Armandine; Pauwels, Hélène; Davy, Philippe; Pételet-Giraud, Emmanuelle; Labasque, Thierry; Roques, Clément; Chatton, Eliot; Bour, Olivier; Ben Maamar, Sarah; Dufresne, Alexis; Khaska, Mahmoud; La Salle, Corinne Le Gal; Barbecot, Florent

    2015-01-01

    Climate change is thought to have major effects on groundwater resources. There is however a limited knowledge of the impacts of past climate changes such as warm or glacial periods on groundwater although marine or glacial fluids may have circulated in basements during these periods. Geochemical investigations of groundwater at shallow depth (80–400 m) in the Armorican basement (western France) revealed three major phases of evolution: (1) Mio-Pliocene transgressions led to marine water introduction in the whole rock porosity through density and then diffusion processes, (2) intensive and rapid recharge after the glacial maximum down to several hundred meters depths, (3) a present-day regime of groundwater circulation limited to shallow depth. This work identifies important constraints regarding the mechanisms responsible for both marine and glacial fluid migrations and their preservation within a basement. It defines the first clear time scales of these processes and thus provides a unique case for understanding the effects of climate changes on hydrogeology in basements. It reveals that glacial water is supplied in significant amounts to deep aquifers even in permafrosted zones. It also emphasizes the vulnerability of modern groundwater hydrosystems to climate change as groundwater active aquifers is restricted to shallow depths. PMID:26392383

  7. Science from Kepler Collateral Data: 50 Kilosecond per Year from 13 Million Star?

    NASA Technical Reports Server (NTRS)

    Kolodziejczak, J. J.; Caldwell, D. A.

    2011-01-01

    As each Kepler frame is read out, light from each star in a CCD column accumulates in successive pixels as they wait for the next row to be read out. This accumulation is the same in the masked rows at the start of the readout and virtual rows at the end of the readout as it is in the science data. A range of these "smear" rows are added together for each long cadence and sent to the ground for calibration purposes. We will introduce and describe this smear collateral data, discuss and demonstrate its potential use for scientific studies exclusive of Kepler calibration,.

  8. Kids with ADHD Make 6.1 Million Doctor Visits a Year in U.S.

    MedlinePlus

    ... but in some settings there are far more boys than girls," Newcorn said. "The fact that these numbers are ... close to the accepted gender ratio suggests that girls with ADHD are being identified and treated. It's not only a disorder of boys." About 48 percent of visits for ADHD by ...

  9. Outstanding imprints of c. 200 million year old earthquakes in seafloor sediments

    NASA Astrophysics Data System (ADS)

    Homberg, Catherine; Schnyder, Johann; Borderie, Sandra; Raine, Rob

    2015-04-01

    Large earthquakes may trigger catastrophic and irreversible events, such as tsunamis, submarine landsides and intense in situ deformation of unlithified sediments. Historic to Recent earthquakes have produced similar phenomena, however, certain identification of sudden tectonic movements from the geological record and especially, detailed recording of their impact are limited. This study focuses on soft sediment deformation (SSD) in the largely-marine Triassic-Jurassic boundary strata of southwest Britain. The studied section is located at Pinhay Bay, in Devon, UK and the rocks represent deposition during a tectonically and climatically intriguing time. The freshwater to brackish and shallow marine deposits of the Penarth Group (Rhaetian - earliest Hettangian, Triassic-Jurassic) are exposed along the coastal cliffs and overlain by the deeper marine, shelf facies of the Lias Group (Hettangian and younger, Early Jurassic). Evidence of re-sedimentation and spectacular SSD exists at various levels in the section. It includes two networks of brittle normal faults, up to two metres long, within two specific units affected by fluidization. At some places, the fluidization is pronounced and only decameter- to metre-scale balls or lenses of the precursor sedimentary deposit (micritic limestone) remain in the center part of the unit. They are observed "floating" in a sedimentary breccia that postdates the re-transportation of the sedimentary particles. Convolute bedding, slumps, drops, small injective peaks and decimeter- to decameter-scale domes are also widespread. Within the defined 13 lithological units, a selection of the SSD deserved specific geometric measurements and thin sections for analysis at a microscopic scale. Our analyses demonstrated a genetic relation between the various SSD types. They can be explained to result from a series of earthquakes along neighboring N-S oriented faults, which bordered the sub-basins accumulating sediment during the Triassic - Early Jurassic. Based on this outstanding example, we proposed a sequential model for the deformation and disturbance of the seafloor subsurface sediments triggered by an earthquake. The sequence of deformation includes brittle failure, fluidization of the failed unit, plastic deformation, and sediment flow at designated places (e.g. close to the fault tips). We also discuss the roles of contrasting stiffness, shear strength, and thickness of the units on the sediment destabilization of freshly deposited sediments that are characterized by a prominent mechanical layering.

  10. Traces of an ancient immune system – how an injured arthropod survived 465 million years ago

    NASA Astrophysics Data System (ADS)

    Schoenemann, Brigitte; Clarkson, Euan N. K.; Høyberget, Magne

    2017-01-01

    This report of a severely injured trilobite from the Middle Ordovician (~465 Ma) accords with a number of similar observations of healed lesions observed in trilobites. The uniqueness of the specimen described here is that the character of the repair-mechanisms is reflected by the secondarily built structures, which form the new surface of the ruptured compound eye. Smooth, repaired areas inside the visual surface advert to a clotting principle, rather similar to those of today, and the way in which broken parts of the exoskeleton fused during restoration seem to simulate modern samples. The irregularity and variance of newly inserted visual units indicate the severity of the injury, which, most probably, was caused by a predatory attack, presumably by a cephalopod; these were most likely, the top predators of the Ordovician. Furthermore, the state of the moulted cephalon tells the dramatic struggle of an organism that lived in the Palaeozoic, to survive. In sum the specimen analysed here is evidence of an ancient clotting mechanism not dissimilar to those of today, rapidly preventing any exsanguination and the breakdown of osmoregulation of this marine arthropod.

  11. Youngest volcanism about 1 million years ago at Kahoolawe Island, Hawaii

    USGS Publications Warehouse

    Sano, H.; Sherrod, D.R.; Tagami, Takahiro

    2006-01-01

    Young volcanic deposits in Kahoolawe Island, cutting up through the caldera-filling lava, colluvium and talus in the west wall of Kanapou Bay, had long been stratigraphically considered the rejuvenated-stage products. New K-Ar ages, combined with magnetic polarity data, show that young volcanism was at about 0.98-1.04 Ma and indicate no substantial quiescence between the filling of the caldera and the young volcanism. This result, and the tholeiitic characteristics of the young deposits, suggest they are a component of late shield-stage volcanism. ?? 2005 Elsevier B.V. All rights reserved.

  12. The Rustenburg Layered Suite (Bushveld Complex) crystallised in less than 1.5 million years

    NASA Astrophysics Data System (ADS)

    Zeh, Armin; Ovtcharova, Maria; Wilson, Allan; Schaltegger, Urs

    2014-05-01

    The timing and crystallisation of the ca. 2.055 Ga old Rustenburg Layered Suite (RLS) of the Bushveld Complex is the subject of ongoing debate. The RLS represents one of the Earth's oldest large igneous provinces, and contains the world's largest reserves of PGE, chromium and vanadium. Previous high-precision U-Pb zircon dating indicated periodic crystallisation over an interval of 5.2 ± 0.79 Ma, with zircon crystallisation events at 2060.5 Ma, below the UG2 chromitite, and at 2055.3 Ma from the Merensky Reef (MR) upwards in the succession (Scoates & Friedman, 2008; Scoates et. al., 2012). Such a prolonged and periodic crystallisation history, however, contradicts field observations and petrological data, which rather require a relatively fast and continuous crystallisation process, periodically interrupted by new magma replenishment (Eales & Cawthorn, 1996; Cawthorn & Walraven, 1998). Here, we present new data from high-precision U-Pb dating, Ti-in-zircon thermometry, and mineral inclusion studies that support this latter interpretation. Our data indicate that zircon crystallised from highly fractionated, silica-saturated intercumulus melts at temperatures between 890 and 700°C most likely continuously from the base of the RLS (Marginal Zone) to the top (Upper Zone), within 0.92 ± 0.57 Ma, between 2055.81 ± 0.20 and 2054.89 ± 0.37 Ma. References Eales, H. V. & Cawthorn, R. G. (1996). The Bushveld Complex, in Layered Intrusions (ed. Cawthorn, R. G.) 181-229 (Elsevier Science, Amsterdam). Cawthorn, R. G. & Walraven, F. (1998). Emplacement and crystallization time for the Bushveld Complex. J. Petrol. 39, 1669-1687. Scoates, J. S. & Friedman, R. M. (2008). Precise age of the platiniferous Merensky Reef, Bushveld Complex, South Africa, by the U-Pb zircon chemical abrasion ID-TIMS technique. Econ. Geol. 103, 465-471. Scoates, J. S., Wall, C. J., Friedman, R. M., VanTongeren, J. A. & Mathez, E. A (2012). Age of the Bushveld Complex. Abstr. Goldschmidt Conference, Montreal, Canada, session 04G (2012).

  13. Infrared mapping resolves soft tissue preservation in 50 million year-old reptile skin.

    PubMed

    Edwards, N P; Barden, H E; van Dongen, B E; Manning, P L; Larson, P L; Bergmann, U; Sellers, W I; Wogelius, R A

    2011-11-07

    Non-destructive Fourier Transform InfraRed (FTIR) mapping of Eocene aged fossil reptile skin shows that biological control on the distribution of endogenous organic components within fossilized soft tissue can be resolved. Mapped organic functional units within this approximately 50 Myr old specimen from the Green River Formation (USA) include amide and sulphur compounds. These compounds are most probably derived from the original beta keratin present in the skin because fossil leaf- and other non-skin-derived organic matter from the same geological formation do not show intense amide or thiol absorption bands. Maps and spectra from the fossil are directly comparable to extant reptile skin. Furthermore, infrared results are corroborated by several additional quantitative methods including Synchrotron Rapid Scanning X-Ray Fluorescence (SRS-XRF) and Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS). All results combine to clearly show that the organic compound inventory of the fossil skin is different from the embedding sedimentary matrix and fossil plant material. A new taphonomic model involving ternary complexation between keratin-derived organic molecules, divalent trace metals and silicate surfaces is presented to explain the survival of the observed compounds. X-ray diffraction shows that suitable minerals for complex formation are present. Previously, this study would only have been possible with major destructive sampling. Non-destructive FTIR imaging methods are thus shown to be a valuable tool for understanding the taphonomy of high-fidelity preservation, and furthermore, may provide insight into the biochemistry of extinct organisms.

  14. Periodic Impact Cratering and Extinction Events Over the Last 260 Million Years

    NASA Technical Reports Server (NTRS)

    Rampino, Michael R.; Caldeira, Ken

    2015-01-01

    The claims of periodicity in impact cratering and biological extinction events are controversial. Anewly revised record of dated impact craters has been analyzed for periodicity, and compared with the record of extinctions over the past 260 Myr. A digital circular spectral analysis of 37 crater ages (ranging in age from 15 to 254 Myr ago) yielded evidence for a significant 25.8 +/- 0.6 Myr cycle. Using the same method, we found a significant 27.0 +/- 0.7 Myr cycle in the dates of the eight recognized marine extinction events over the same period. The cycles detected in impacts and extinctions have a similar phase. The impact crater dataset shows 11 apparent peaks in the last 260 Myr, at least 5 of which correlate closely with significant extinction peaks. These results suggest that the hypothesis of periodic impacts and extinction events is still viable.

  15. Infrared mapping resolves soft tissue preservation in 50 million year-old reptile skin

    PubMed Central

    Edwards, N. P.; Barden, H. E.; van Dongen, B. E.; Manning, P. L.; Larson, P. L.; Bergmann, U.; Sellers, W. I.; Wogelius, R. A.

    2011-01-01

    Non-destructive Fourier Transform InfraRed (FTIR) mapping of Eocene aged fossil reptile skin shows that biological control on the distribution of endogenous organic components within fossilized soft tissue can be resolved. Mapped organic functional units within this approximately 50 Myr old specimen from the Green River Formation (USA) include amide and sulphur compounds. These compounds are most probably derived from the original beta keratin present in the skin because fossil leaf- and other non-skin-derived organic matter from the same geological formation do not show intense amide or thiol absorption bands. Maps and spectra from the fossil are directly comparable to extant reptile skin. Furthermore, infrared results are corroborated by several additional quantitative methods including Synchrotron Rapid Scanning X-Ray Fluorescence (SRS-XRF) and Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS). All results combine to clearly show that the organic compound inventory of the fossil skin is different from the embedding sedimentary matrix and fossil plant material. A new taphonomic model involving ternary complexation between keratin-derived organic molecules, divalent trace metals and silicate surfaces is presented to explain the survival of the observed compounds. X-ray diffraction shows that suitable minerals for complex formation are present. Previously, this study would only have been possible with major destructive sampling. Non-destructive FTIR imaging methods are thus shown to be a valuable tool for understanding the taphonomy of high-fidelity preservation, and furthermore, may provide insight into the biochemistry of extinct organisms. PMID:21429928

  16. Intensified climate-driven exhumation along the South Himalayan Front since one million years ago

    NASA Astrophysics Data System (ADS)

    Yu, Xiangjiang; Ji, Jianqing; Wang, Fengyi; Zhong, Dalai

    2017-04-01

    This paper builds a database of apatite fission track (AFT) ages and thermal-modeling results covering the whole southern Tibetan Plateau, providing detailed information on the cooling and erosion process of the modern landscape evolution and comparing with the distribution of climatic factors. Large-scale AFT age distribution and thermal-history modeling results indicate extraordinarily intense erosion along the South Himalayan Front and relatively weak erosion in the interior of the plateau. AFT samples from different regions plot into different partitions on the elevation vs AFT age diagram, and there is an excellent coupling between AFT ages and climatic factors. Based on AFT thermal-history modeling results, an intensified erosion event since ∼1 Myr ago has been identified along the South Himalayan Front. The varied AFT ages along the South Himalayan Front are probably induced by differential intensity of erosion in the same cooling event rather than the time when the rapid cooling event began. Meanwhile, the spatiotemporal coupling of climatic factors and the intensified erosion belt suggests that climatic transition is the key factor dominating the rapid exhumation event since ∼1 Myr.

  17. Imprint of a 2 Million Year Old Source on the Cosmic-Ray Anisotropy

    NASA Astrophysics Data System (ADS)

    Savchenko, V.; Kachelrieß, M.; Semikoz, D. V.

    2015-08-01

    We study numerically the anisotropy of the cosmic-ray (CR) flux emitted by a single source calculating the trajectories of individual CRs. We show that the contribution of a single source to the observed anisotropy is determined solely by the fraction the source contributes to the total CR intensity, its age, and its distance and does not depend on the CR energy at late times. Therefore, the observation of a constant dipole anisotropy indicates that a single source dominates the CR flux in the corresponding energy range. A natural explanation for the plateau between 2-20 TeV observed in the CR anisotropy is thus the presence of a single, nearby source. For the source age of 2 Myr, as suggested by the explanation of the antiproton and positron data from PAMELA and AMS-02 through a local source, we determine the source distance as ˜200 pc. Combined with the contribution of the global CR sea calculated in the escape model, we can explain qualitatively the data for the dipole anisotropy. Our results suggest that the assumption of a smooth CR source distribution should be abandoned between ≃200 GeV and 1 PeV.

  18. Nd and Sr isotopic evolution of the oceans of the past 800 million years

    SciTech Connect

    Keto, L.S.

    1987-01-01

    This thesis comprises four related studies on the Nd and Sr isotopic composition of oceans through time. The first study uses Lower Paleozoic fossil samples of Europe and North America to establish that phosphatic fossils retain the distinct Nd isotopic signatures of paleoceans. These signatures may be used as tracers of paleoceanic water masses through time and consequently as tracers of paleogeography. The second study provides a framework for understanding and interpreting the Nd isotopic record of individual oceans as well as for determination of the mean oceanic isotopic compositions of Nd. Variations in individual ocean Nd isotopic compositions through time have implications for regional geology and paleoceanic circulation whereas the mean oceanic Nd isotopic compositions have implications for the global inputs to the oceans from the continents. The third study extends the record of well-defined /sup 87/Sr//sup 86/Sr values for seawater into the Late Proterozoic using carbonate samples of East Greenland and Svalbard. A thermal subsidence model is used to quantify the ages of these samples. Criterion for recognizing samples which have preserved /sup 87/Sr//sup 86/Sr seawater primary values are developed and the Sr and C isotopic records for paleoseawater of the past 1000 Ma are compared. The fourth study integrates the paleocean Nd and Sr isotopic records, as developed in the first parts of the thesis, into a model of the changing chemical and mass inputs to the oceans of the past 800 Ma.

  19. Evidence for Life on Earth before 3,800 Million Years Ago

    NASA Technical Reports Server (NTRS)

    Mojzsis, S. J.; Arrhenius, G.; McKeegan, K. D.; Harrison, T. M.; Nutman, A. P.; Friend, C. R. L.

    1996-01-01

    It is unknown when life first appeared on Earth. The earliest known microfossils (approx. 3,500 Myr before present) are structurally complex, and if it is assumed that the associated organisms required a long time to develop this degree of complexity, then the existence of life much earlier than this can be argued. But the known examples of crustal rocks older than approx. 3,500 Myr have experienced intense metamorphism, which would have obliterated any fragile microfossils contained therein. It is therefore necessary to search for geochemical evidence of past biotic activity that has been preserved within minerals that are resistant to metamorphism. Here we report ion-microprobe measurements of the carbon-isotope composition of carbonaceous inclusions within grains of apatite (basic calcium phosphate) from the oldest known sediment sequences a approx. 3,800 Myr-old banded iron formation from the Isua supracrustal belt, West Greenland, and a similar formation from the nearby Akilia island that is possibly older than 3,850 Myr. The carbon in the carbonaceous inclusions is isotopically light, indicative of biological activity; no known abiotic process can explain the data. Unless some unknown abiotic process exists which is able both to create such isotopically light carbon and then selectively incorporate it into apatite grains, our results provide evidence for the emergence of life on Earth by at least 3,800 Myr before present.

  20. The "Sudden Explosion" of Animal Fossils about 600 Million Years Ago: Why?

    ERIC Educational Resources Information Center

    Kaveski, Sharon; Margulis, Lynn

    1983-01-01

    Discusses the "sudden explosion" of animal fossils during the Cambrian era, suggesting that the "explosion" is a result of organic evolution, leading to remarkably preservable calcareous skeletons. Suggests that earlier organisms were soft-bodied and consequently were poorly preserved in the fossil record. (JN)

  1. Reproductive niche conservatism in the isolated New Zealand flora over 23 million years

    PubMed Central

    Conran, John G.; Lee, William G.; Lee, Daphne E.; Bannister, Jennifer M.; Kaulfuss, Uwe

    2014-01-01

    The temporal stability of plant reproductive features on islands has rarely been tested. Using flowers, fruits/cones and seeds from a well-dated (23 Ma) Miocene Lagerstätte in New Zealand, we show that across 23 families and 30 genera of forest angiosperms and conifers, reproductive features have remained constant for more than 20 Myr. Insect-, wind- and bird-pollinated flowers and wind- and bird-dispersed diaspores all indicate remarkable reproductive niche conservatism, despite widespread environmental and biotic change. In the past 10 Myr, declining temperatures and the absence of low-latitude refugia caused regional extinction of thermophiles, while orogenic processes steepened temperature, precipitation and nutrient gradients, limiting forest niches. Despite these changes, the palaeontological record provides empirical support for evidence from phylogeographical studies of strong niche conservatism within lineages and biomes. PMID:25319820

  2. A 400 million year carbon isotope record of pedogenic carbonate: Implications for paleoatmospheric carbon dioxide

    SciTech Connect

    Ekart, D.D.; Cerling, T.E.; Montanez, I.P.; Tabor, N.J.

    1999-12-01

    A 400 record of atmospheric carbon dioxide levels has been estimated by applying a CO{sub 2} paleobarometer to a database of 758 analyses of paleosol (fossil soil) carbonates. This database is a compilation of new data and previously published values from the literature. Many new analyses of Mesozoic paleosols are reported, an era poorly represented in the literature. Results indicate that large fluctuations in atmospheric carbon dioxide levels have occurred over the study interval, ranging from the current level up to ten times the current level. Declining pCO{sub 2} levels through the middle Paleozoic culminate in low levels in the Early Permian. An abrupt increase in pCO{sub 2} in the Early Permian is followed by a decrease prior to the Permo-Triassic boundary. Carbon dioxide levels increase through the Triassic to approx. 3,000 ppmV, a level maintained through the Jurassic period. Levels lowered through the Cretaceous, dropping to less than 1,000 ppmV prior to the Cretaceous-Tertiary boundary. Relatively low levels persisted throughout the Cenozoic, with some evidence of higher levels in the Eocene and Oligocene.

  3. Nocturnality in synapsids predates the origin of mammals by over 100 million years.

    PubMed

    Angielczyk, K D; Schmitz, L

    2014-10-22

    Nocturnality is widespread among extant mammals and often considered the ancestral behavioural pattern for all mammals. However, mammals are nested within a larger clade, Synapsida, and non-mammalian synapsids comprise a rich phylogenetic, morphological and ecological diversity. Even though non-mammalian synapsids potentially could elucidate the early evolution of diel activity patterns and enrich the understanding of synapsid palaeobiology, data on their diel activity are currently unavailable. Using scleral ring and orbit dimensions, we demonstrate that nocturnal activity was not an innovation unique to mammals but a character that appeared much earlier in synapsid history, possibly several times independently. The 24 Carboniferous to Jurassic non-mammalian synapsid species in our sample featured eye morphologies consistent with all major diel activity patterns, with examples of nocturnality as old as the Late Carboniferous (ca 300 Ma). Carnivores such as Sphenacodon ferox and Dimetrodon milleri, but also the herbivorous cynodont Tritylodon longaevus were likely nocturnal, whereas most of the anomodont herbivores are reconstructed as diurnal. Recognizing the complexity of diel activity patterns in non-mammalian synapsids is an important step towards a more nuanced picture of the evolutionary history of behaviour in the synapsid clade.

  4. Seven 365-Million-Year-Old Trilobites Moulting within a Nautiloid Conch

    PubMed Central

    Zong, Rui-Wen; Fan, Ruo-Ying; Gong, Yi-Ming

    2016-01-01

    A nautiloid conch containing many disarticulated exoskeletons of Omegops cornelius (Phacopidae, Trilobita) was found in the Upper Devonian Hongguleleng Formation of the northwestern margin of the Junggar Basin, NW China. The similar number of cephala, thoraces and pygidia, unbroken thoraces, explicit exuviae, and lack of other macrofossils in the conch, indicate that at least seven individual trilobites had moulted within the nautiloid living chamber, using the vacant chamber of a dead nautiloid as a communal place for ecdysis. This exuvial strategy manifests cryptic behaviour of trilobites, which may have resulted from the adaptive evolution induced by powerful predation pressure, unstable marine environments, and competition pressure of organisms occupying the same ecological niche in the Devonian period. The unusual presence of several trilobites moulting within a nautiloid conch is possibly associated with social behaviours in face of a serious crisis. New materials in this study open a window for understanding the survival strategy of marine benthic organisms, especially predator-prey interactions and the behavioural ecology of trilobites in the middle Palaeozoic. PMID:27703275

  5. Tapeworm eggs in a 270 million-year-old shark coprolite.

    PubMed

    Dentzien-Dias, Paula C; Poinar, George; de Figueiredo, Ana Emilia Q; Pacheco, Ana Carolina L; Horn, Bruno L D; Schultz, Cesar L

    2013-01-01

    Remains of parasites in vertebrates are rare from the Mesozoic and Paleozoic. Once most parasites that live in - or pass through - the gastrointestinal tract of vertebrates, fossil feces (coprolites) or even intestinal contents (enterolites) can eventually preserve their remains. Here we announce the discovery of a spiral shark coprolite from the Paleozoic bearing a cluster of 93 small oval-elliptical smooth-shelled structures, interpreted as eggs of a tapeworm.The eggs were found in a thin section of an elasmobranch coprolite. Most of the eggs are filled by pyrite and some have a special polar swelling (operculum), suggesting they are non-erupted eggs. One of the eggs contains a probable developing larva. The eggs are approximately 145-155 µm in length and 88-100 µm in width and vary little in size within the cluster. The depositional and morphological features of the eggs closely resemble those of cestodes. Not only do the individual eggs have features of extant tapeworms, but their deposition all together in an elongate segment is typical to modern tapeworm eggs deposited in mature segments (proglottids). This is the earliest fossil record of tapeworm parasitism of vertebrates and establishes a timeline for the evolution of cestodes. This discovery shows that the fossil record of vertebrate intestinal parasites is much older than was hitherto known and that the interaction between tapeworms and vertebrates occurred at least since the Middle-Late Permian.

  6. A palaeobiogeographic model for biotic diversification within Amazonia over the past three million years.

    PubMed

    Ribas, Camila C; Aleixo, Alexandre; Nogueira, Afonso C R; Miyaki, Cristina Y; Cracraft, Joel

    2012-02-22

    Many hypotheses have been proposed to explain high species diversity in Amazonia, but few generalizations have emerged. In part, this has arisen from the scarcity of rigorous tests for mechanisms promoting speciation, and from major uncertainties about palaeogeographic events and their spatial and temporal associations with diversification. Here, we investigate the environmental history of Amazonia using a phylogenetic and biogeographic analysis of trumpeters (Aves: Psophia), which are represented by species in each of the vertebrate areas of endemism. Their relationships reveal an unforeseen 'complete' time-slice of Amazonian diversification over the past 3.0 Myr. We employ this temporally calibrated phylogeny to test competing palaeogeographic hypotheses. Our results are consistent with the establishment of the current Amazonian drainage system at approximately 3.0-2.0 Ma and predict the temporal pattern of major river formation over Plio-Pleistocene times. We propose a palaeobiogeographic model for the last 3.0 Myr of Amazonian history that has implications for understanding patterns of endemism, the temporal history of Amazonian diversification and mechanisms promoting speciation. The history of Psophia, in combination with new geological evidence, provides the strongest direct evidence supporting a role for river dynamics in Amazonian diversification, and the absence of such a role for glacial climate cycles and refugia.

  7. Biomolecules preserved in ca. 168 million year old fossil conifer wood.

    PubMed

    Marynowski, Leszek; Otto, Angelika; Zatoń, Michał; Philippe, Marc; Simoneit, Bernd R T

    2007-03-01

    Biomarkers are widely known to occur in the fossil record, but the unaltered biomolecules are rarely reported from sediments older than Paleogene. Polar terpenoids, the natural products most resistant to degradation processes, were reported mainly from the Tertiary conifers, and the oldest known are Cretaceous in age. In this paper, we report the occurrence of relatively high concentrations of ferruginol derivatives and other polar diterpenoids, as well as their diagenetic products, in a conifer wood Protopodocarpoxylon from the Middle Jurassic of Poland. Thus, the natural product terpenoids reported in this paper are definitely the oldest polar biomolecules detected in geological samples. The extracted phenolic abietanes like ferruginol and its derivatives (6,7-dehydroferruginol, sugiol, 11,14-dioxopisiferic acid) are produced only by distinct conifer families (Cupressaceae s. l., Podocarpaceae and Araucariaceae), to which Protopodocarpoxylon could belong based on anatomical characteristics. Therefore, the natural product terpenoids are of great advantage in systematics of fossil plant remains older than Paleogene and lacking suitable anatomical preservation.

  8. Biomolecules preserved in ca. 168 million year old fossil conifer wood

    NASA Astrophysics Data System (ADS)

    Marynowski, Leszek; Otto, Angelika; Zatoń, Michał; Philippe, Marc; Simoneit, Bernd R. T.

    2007-03-01

    Biomarkers are widely known to occur in the fossil record, but the unaltered biomolecules are rarely reported from sediments older than Paleogene. Polar terpenoids, the natural products most resistant to degradation processes, were reported mainly from the Tertiary conifers, and the oldest known are Cretaceous in age. In this paper, we report the occurrence of relatively high concentrations of ferruginol derivatives and other polar diterpenoids, as well as their diagenetic products, in a conifer wood Protopodocarpoxylon from the Middle Jurassic of Poland. Thus, the natural product terpenoids reported in this paper are definitely the oldest polar biomolecules detected in geological samples. The extracted phenolic abietanes like ferruginol and its derivatives (6,7-dehydroferruginol, sugiol, 11,14-dioxopisiferic acid) are produced only by distinct conifer families (Cupressaceae s. l., Podocarpaceae and Araucariaceae), to which Protopodocarpoxylon could belong based on anatomical characteristics. Therefore, the natural product terpenoids are of great advantage in systematics of fossil plant remains older than Paleogene and lacking suitable anatomical preservation.

  9. One hundred million years of skin feeding? Extended parental care in a Neotropical caecilian (Amphibia: Gymnophiona).

    PubMed

    Wilkinson, Mark; Kupfer, Alexander; Marques-Porto, Rafael; Jeffkins, Hilary; Antoniazzi, Marta M; Jared, Carlos

    2008-08-23

    Maternal dermatophagy, the eating of maternal skin by offspring, is an unusual form of parental investment involving co-evolved specializations of both maternal skin and offspring dentition, which has been recently discovered in an African caecilian amphibian. Here we report the discovery of this form of parental care in a second, distantly related Neotropical species Siphonops annulatus, where it is characterized by the same syndrome of maternal and offspring specializations. The detailed similarities of skin feeding in different caecilian species provide strong evidence of its homology, implying its presence in the last common ancestor of these species. Biogeographic considerations, the separation of Africa and South American land masses and inferred timescales of amphibian diversification all suggest that skin feeding is an ancient form of parental care in caecilians, which has probably persisted in multiple lineages for more than 100 Myr. These inferences support the hypotheses that (i) maternal dermatophagy is widespread in oviparous direct-developing caecilians, and (ii) that viviparous caecilians that feed on the hypertrophied maternal oviduct evolved from skin-feeding ancestors. In addition to skin-feeding, young S. annulatus were observed to congregate around, and imbibe liquid exuded from, the maternal cloacal opening.

  10. Freezing of ridges and water networks preserves the Gamburtsev Subglacial Mountains for millions of years

    NASA Astrophysics Data System (ADS)

    Creyts, Timothy T.; Ferraccioli, Fausto; Bell, Robin E.; Wolovick, Michael; Corr, Hugh; Rose, Kathryn C.; Frearson, Nicholas; Damaske, Detlef; Jordan, Tom; Braaten, David; Finn, Carol

    2014-11-01

    Once an ice sheet grows beyond a critical thickness, the basal thermal regime favors melting and development of subglacial water networks. Subglacial water is necessary for bedrock erosion, but the exact mechanisms that lead to preservation of subglacial topography are unclear. Here we resolve the freezing mechanisms that lead to long-term, high-altitude preservation across the Gamburtsev Subglacial Mountains in East Antarctica. Analyses of a comprehensive geophysical data set reveal a large-scale water network along valley floors. The ice sheet often drives subglacial water up steep topography where it freezes along high ridges beneath thinner ice. Statistical tests of hypsometry show the Gamburtsevs resemble younger midlatitude mountains, indicating exceptional preservation. We conclude that the Gamburtsevs have been shielded from erosion since the latest Eocene (˜34 Ma). These freezing mechanisms likely account for the spatial and temporal patterns of erosion and preservation seen in other glaciated mountain ranges.

  11. Evidence for a 20° tilting of the Earth's rotation axis 110 million years ago

    NASA Astrophysics Data System (ADS)

    Prévot, Michel; Mattern, Estelle; Camps, Pierre; Daignières, Marc

    2000-07-01

    True polar wander (TPW), the shift of the Earth's rotation axis with respect to the entire globe, is most probably due to mass redistribution in the Earth's mantle as a result of convection. Using a new rigorously selected paleomagnetic database gathering only directions obtained from magmatic rocks, we find that TPW has been clearly intermittent over the last 200 Myr with two long periods of strict standstill from the present to 80 Ma and from approximately 150 to 200 Ma. A single period of shifting is observed, between 80 and about 150 Ma. This period culminates around 110 Ma in an 20° abrupt tilting during which an angular speed exceeding 5°/Myr (0.5 m/yr) may have been reached. Assuming that the time-averaged geomagnetic field is axial, our results indicate that the changes in the position of the rotation axis, and therefore in the inertia tensor of the Earth, are intermittent. We suggest that a major reorganization of the mass distribution in the Earth's mantle occurred in the Lower Cretaceous. This event, concomitant with plume hyperactivity at the Earth's surface and probable drastic changes at the core-mantle boundary attested by the inhibition of geomagnetic reversals, suggests unmixing of upper and lower mantle by avalanching of upper mantle material down to the core-mantle boundary. The astonishingly strict stability of the time-averaged position of the rotation axis before and after this episode of shifting implies the existence of some steady convection which does not modify the large-scale distribution of mass within the mantle. Given the intermittence of mantle avalanching, we suggest that these long periods of stability correspond to the temporary reestablishment of a basically two-layered convection system within the mantle.

  12. Fifty-five million years of Tibetan evolution recorded in the Indus Fan

    NASA Astrophysics Data System (ADS)

    Clift, Peter; Shimizu, Nobu; Layne, Graham; Gaedicke, Christoph; Schlter, H.-U.; Clark, Marin; Amjad, Shahid

    Although the Indus Fan is only about one-third of the volume of its giant neighbor in the Bay of Bengal, it is one of the largest sediment bodies in the ocean basins, totaling ˜5×106 km3. Its detrital sedimentary record is an important repository of information on the uplift and erosion of the western Himalaya. New seismic and provenance data from the Pakistan margin now suggest that the Indus River and fan system was initiated shortly after the India-Asia collision at ˜5 Ma. The modern Indus drainage basin is dominated by the high peaks of the Karakoram, Kohistan, and other tectonic units of the Indus Suture Zone rather than the High Himalaya. The Indus River, which rises in western Tibet near Mount Kailas, follows the Indus Suture Zone along strike before cutting orthogonally through the Himalaya to the Arabian Sea. The other tributaries to the Indus, such as the Chenab and Sutlej, do drain the crystalline High Himalayan range, but do so in an area where its topography is much reduced (Figure 1). In contrast, the Bengal Fans main feeder rivers, the Ganges and Brahmaputra, follow the High Himalaya along strike for much of the length of the orogen. In practice, this means that the Bengal Fan is swamped by the large volume of material derived from the rapidly unroofing High Himalaya [France-Lanord et al, 1993], while the Indus Fan is dominated by tectonic units adjacent to the suture zone, including western Tibet. This allows their erosional signal to be more readily isolated in the Indus Fan compared to in the Bengal.

  13. 200 million years of komatiite evolution in the Barberton Greenstone Belt, South Africa

    NASA Astrophysics Data System (ADS)

    Christoph, Robin; Arndt, Nick; Byerly, Gary; Puchtel, Igor; Blichert-Toft, Janne; Wilson, Allan

    2010-05-01

    Komatiites with complex and contrasting chemical compositions erupted throughout the 200 m.y. history of the Barberton greenstone belt in South Africa. The oldest well-preserved examples, from the ca. 3.5 Ga Komati Formation, display a range of volcanic structures, from thin differentiated spinifex-textured flows to much thicker flows or sills composed mainly of massive olivine cumulate. Pyroxene spinifex layers that cap the latter units indicate crystallization from komatiitic basaltic liquids. Although some rare, unusually coarse, vesicular, completely serpentinized units may have contained a small fraction of water, most of the flows are essentially anhydrous. Two geochemical types are present in the Komati Fm; Al-depleted komatiites with moderately enriched LREE and depleted HREE, and Al-undepleted komatiites with near-chondritic REE ratios. Komatiites from the 3.2 Ga Mendon and Weltevreden Fm display two patterns -Al-undepleted with near-chondritic REE ratios and Al-enriched with extremely low REE concentrations and marked depletion of LREE. In many units, both geochemical types are present. The Al- and HREE-depletion of Komati Fm magmas indicates that residual garnet was retained in the mantle source and their high MgO contents require that melting was at great depth. Up to 30% batch melting at 300 km depth is indicated; the high percentage of batch melting is possible because melt is neutrally buoyant at these depths. The Al-undepleted to enrichedmagmas formed by up to 50% cumulative fractional melting that terminated at shallower depth. The. presence of both types inseveral units points to complex dynamics in the mantle plumes that yielded these magmas. Epsilon Nd in all Barbertonkomatiites ranges from 0 to +2; epsilon Hf from +2 to +7; gamma Os from 0 to +3.7. The combination of fractionated REE, positive epsilon Nd and Hf, and near-chondritic Os in certain komatiites is attributed to differentiation of the komatiite sourcevery early in Earth history followed by fractionation during komatiite formation.

  14. A palaeobiogeographic model for biotic diversification within Amazonia over the past three million years

    PubMed Central

    Ribas, Camila C.; Aleixo, Alexandre; Nogueira, Afonso C. R.; Miyaki, Cristina Y.; Cracraft, Joel

    2012-01-01

    Many hypotheses have been proposed to explain high species diversity in Amazonia, but few generalizations have emerged. In part, this has arisen from the scarcity of rigorous tests for mechanisms promoting speciation, and from major uncertainties about palaeogeographic events and their spatial and temporal associations with diversification. Here, we investigate the environmental history of Amazonia using a phylogenetic and biogeographic analysis of trumpeters (Aves: Psophia), which are represented by species in each of the vertebrate areas of endemism. Their relationships reveal an unforeseen ‘complete’ time-slice of Amazonian diversification over the past 3.0 Myr. We employ this temporally calibrated phylogeny to test competing palaeogeographic hypotheses. Our results are consistent with the establishment of the current Amazonian drainage system at approximately 3.0–2.0 Ma and predict the temporal pattern of major river formation over Plio-Pleistocene times. We propose a palaeobiogeographic model for the last 3.0 Myr of Amazonian history that has implications for understanding patterns of endemism, the temporal history of Amazonian diversification and mechanisms promoting speciation. The history of Psophia, in combination with new geological evidence, provides the strongest direct evidence supporting a role for river dynamics in Amazonian diversification, and the absence of such a role f