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Sample records for 4-5 million years

  1. Iraq challenges sanctions, offers 4.5 million b/d developable capacity

    SciTech Connect

    Stauffer, T.R.

    1995-04-10

    The prospective oil deals of the century were unveiled last month in Baghdad at the unlikely venue of the first international oil conference in Iraq in decades. In a dramatic twist Iraq detailed 33 oil fields that are now open for joint development with foreign partners. The productive capacity of the listed fields totals some 4.5 million b/d, and the underlying proved reserves exceed 50 billion bbl--equal to more than US and Canadian reserves combined. Reversing its prior compulsive secretiveness concerning oil affairs, the government cleared at the highest level the proposal to publicize the available resources and to offer corroborative detail. ``Four and a half million b/d is an awful lot of oil,`` noted one foreign oilman who was loath to be quoted because his company feared possible reprisals in the US. The economic bait was both clear and enticing. Iraq chose the public forum to signal to the world the gains that could accrue to the first countries that break with the US over continuing the sanctions. The paper discusses the political impacts, the substantial offerings, exploitation costs, and bypassing sanctions.

  2. Early Number and Arithmetic Performance of Ecuadorian 4-5-Year-Olds

    ERIC Educational Resources Information Center

    Bojorque, Gina; Torbeyns, Joke; Moscoso, Jheni; Van Nijlen, Daniël; Verschaffel, Lieven

    2015-01-01

    This study aimed at (a) constructing a reliable and valid test to assess Ecuadorian 4-5-year olds' number and arithmetic skills; (b) providing empirical data on Ecuadorian 4-5-year olds' number and arithmetic skills; and (c) confronting these children's actual performances with the performances expected by national experts in this domain. We…

  3. Effectiveness of Multipurpose Unit Early Classroom Intervention Program for 4-5-Year-Old Children

    ERIC Educational Resources Information Center

    Celebioglu Morkoc, Ozlem; Aktan Acar, Ebru

    2014-01-01

    This research examined the effectiveness of Multipurpose Unit Early Classroom Intervention Program (MUECIP) prepared for 4-5-year-old (48-60 months) children whose development is at risk because of their families' socioeconomic conditions. The research adopted a preliminary test-final test control group trial model. The research participants…

  4. Ensemble Perception of Size in 4-5-Year-Old Children

    ERIC Educational Resources Information Center

    Sweeny, Timothy D.; Wurnitsch, Nicole; Gopnik, Alison; Whitney, David

    2015-01-01

    Groups of objects are nearly everywhere we look. Adults can perceive and understand the "gist" of multiple objects at once, engaging ensemble-coding mechanisms that summarize a group's overall appearance. Are these group-perception mechanisms in place early in childhood? Here, we provide the first evidence that 4-5-year-old children use…

  5. Sepsis After Cardiac Surgery Early in Infancy and Adverse 4.5-Year Neurocognitive Outcomes

    PubMed Central

    Sidhu, Naveen; Joffe, Ari R; Doughty, Paul; Vatanpour, Shabnam; Dinu, Irina; Alton, Gwen; Acton, Bryan; Robertson, Charlene M T

    2015-01-01

    Background We aimed to determine whether sepsis is associated with neurocognitive outcomes 4.5 years after congenital heart disease surgery in early infancy. Methods and Results A secondary analysis from a prospective inception cohort included all children having congenital heart disease surgery done at ≤6 weeks of age with cardiopulmonary bypass at the Western Canadian referral center from 1996 to 2009. Follow-up at the referral center determined the primary outcomes at 4.5 years with full-scale, performance, and verbal intelligence quotients on the Wechsler Preschool and Primary Scale of Intelligence. Perioperative variables were collected prospectively, and confirmation of blood culture–positive sepsis was done retrospectively. Multiple linear regression models for neurocognitive outcomes and multiple Cox proportional hazards regression for mortality were determined. Sepsis occurred in 97 of 502 patients (19%) overall and in 76 of 396 survivors (19%) with 4.5-year follow-up. By 4.5 years, there were 91 (18%) deaths, and 396 of 411 survivors (96%) had follow-up completed. Extracorporeal membrane oxygenation was associated with worse scores on all neurocognitive outcomes on multivariable regression; the association between extracorporeal membrane oxygenation and full-scale intelligence quotient had a regression coefficient of −13.6 (95% CI −21.3 to −5.9; P =0.001). Sepsis perioperatively was associated with performance and verbal intelligence quotients, with a trend for full-scale intelligence quotient (P =0.058) on multivariable regression. The regression coefficient for sepsis was strongest for performance intelligence quotient (−5.31; 95% CI −9.84 to −0.78; P =0.022). Sepsis was not but extracorporeal membrane oxygenation was associated with mortality by 4.5 years. Conclusions Perioperative sepsis and extracorporeal membrane oxygenation were associated with adverse neurocognitive outcomes on multivariable regression. Quality improvement to

  6. Rules for pluralization in African American English: Evidence from 4-, 5-, and 6-year-olds

    NASA Astrophysics Data System (ADS)

    Trent-Brown, Sonja A.

    2005-09-01

    This study investigated the African American English (AAE) forms produced by 4-, 5-, and 6-year-old children when pluralizing words ending in final consonant clusters. Participants were 105 child and 45 adult speakers of AAE. Speakers provided verbal responses to pictures of cartoon-like creatures with nonsense word names. Responses were recorded and presented to experienced listeners for language set and singular versus plural judgments. An acoustical analysis was conducted for comparison to the perceptual findings. Results suggest that although [s] inflection is nonobligatory in AAE, there are many instances in which it does occur. Variation in plural forms across final consonant clusters is discussed as well as other markers for pluralization in the absence of the [s] morpheme.

  7. Stereopsis Results at 4.5 Years of Age in the Infant Aphakia Treatment Study

    PubMed Central

    Hartmann, E. Eugenie; Stout, Ann U.; Lynn, Michael J.; Yen, Kimberly G.; Kruger, Stacey J.; Lambert, Scott R.

    2014-01-01

    Purpose To determine whether stereopsis of infants treated for monocular cataracts varies with the type of optical correction used. Design Randomized prospective clinical trial Methods The Infant Aphakia Treatment Study randomized 114 patients with unilateral cataracts at age 1 to 7 months to either primary intraocular lens (IOL) or contact lens correction. At 4.5 years of age a masked examiner assessed stereopsis on these patients using three different tests: 1) Frisby; 2) Randot Preschool; and 3) Titmus fly. Results Twenty-eight patients (25%) had a positive response to at least one of the stereopsis tests. There was no statistically significant difference in stereopsis between the two treatment groups. Frisby (contact lens, 6 (11%); IOL, 7 (13%); p=0.99), Randot (contact lens, 3 (6%); IOL, 1 (2%); p=0.62) or Titmus: (contact lens, 8 (15%); IOL, 13 (23%); p=0.34). The median age at surgery for patients with stereopsis was younger than for those without stereopsis (1.2 versus 2.4 months; p=0.002). The median visual acuity for patients with stereopsis was better than for those without stereopsis (20/40 vs. 20/252; p=0.0003). Conclusion The type of optical correction did not influence stereopsis outcomes. However, two other factors did: age at surgery and visual acuity in the treated eye at age 4.5 years. Early surgery for unilateral congenital cataract and the presence of visual acuity better than or equal to 20/40 appear to be more important than the type of initial optical correction used for the development of stereopsis. PMID:25261241

  8. 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

  9. Ensemble perception of size in 4-5-year-old children.

    PubMed

    Sweeny, Timothy D; Wurnitsch, Nicole; Gopnik, Alison; Whitney, David

    2015-07-01

    Groups of objects are nearly everywhere we look. Adults can perceive and understand the 'gist' of multiple objects at once, engaging ensemble-coding mechanisms that summarize a group's overall appearance. Are these group-perception mechanisms in place early in childhood? Here, we provide the first evidence that 4-5-year-old children use ensemble coding to perceive the average size of a group of objects. Children viewed a pair of trees, with each containing a group of differently sized oranges. We found that, in order to determine which tree had the larger oranges overall, children integrated the sizes of multiple oranges into ensemble representations. This pooling occurred rapidly, and it occurred despite conflicting information from numerosity, continuous extent, density, and contrast. An ideal observer analysis showed that although children's integration mechanisms are sensitive, they are not yet as efficient as adults'. Overall, our results provide a new insight into the way children see and understand the environment, and they illustrate the fundamental nature of ensemble coding in visual perception.

  10. Searching for Organics Preserved in 4.5 Billion Year Old Salt

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael E.; Fries, M.; Steele, A.; Bodnar, R.

    2012-01-01

    Our understanding of early solar system fluids took a dramatic turn a decade ago with the discovery of fluid inclusion-bearing halite (NaCl) crystals in the matrix of two freshly fallen brecciated H chondrite falls, Monahans and Zag. Both meteorites are regolith breccias, and contain xenolithic halite (and minor admixed sylvite -- KCl, crystals in their regolith lithologies. The halites are purple to dark blue, due to the presence of color centers (electrons in anion vacancies) which slowly accumulated as 40K (in sylvite) decayed over billions of years. The halites were dated by K-Ar, Rb-Sr and I-Xe systematics to be 4.5 billion years old. The "blue" halites were a fantastic discovery for the following reasons: (1) Halite+sylvite can be dated (K is in sylvite and will substitute for Na in halite, Rb substitutes in halite for Na, and I substitutes for Cl). (2) The blue color is lost if the halite dissolves on Earth and reprecipitates (because the newly-formed halite has no color centers), so the color serves as a "freshness" or pristinity indicator. (3) Halite frequently contains aqueous fluid inclusions. (4) Halite contains no structural oxygen, carbon or hydrogen, making them ideal materials to measure these isotopic systems in any fluid inclusions. (5) It is possible to directly measure fluid inclusion formation temperatures, and thus directly measure the temperature of the mineralizing aqueous fluid. In addition to these two ordinary chondrites halite grains have been reliably reported in several ureilites, an additional ordinary chondrite (Jilin), and in the carbonaceous chondrite (Murchison), although these reports were unfortunately not taken seriously. We have lately found additional fluid inclusions in carbonates in several additional carbonaceous chondrites. Meteoritic aqueous fluid inclusions are apparently relatively widespread in meteorites, though very small and thus difficult to analyze.

  11. Behavioral Profiles in 4-5 Year-Old Children: Normal and Pathological Variants

    ERIC Educational Resources Information Center

    Larsson, Jan-Olov; Bergman, Lars R.; Earls, Felton; Rydelius, Per-Anders

    2004-01-01

    Normal and psychopathological patterns of behavior symptoms in preschool children were described by a classification approach using cluster analysis. The behavior of 406 children, average age 4 years 9 months, from the general population was evaluated at home visits. Seven clusters were identified based on empirically defined dimensions:…

  12. Woodwaste saves Louisiana-Pacific $164 million a year

    SciTech Connect

    Not Available

    1981-11-01

    Louisiana Pacific is reported to be producing 74% of its total energy requirements from woodwaste. The company is saving the equivalent of more than five million barrels of oil a year with its waste conversion systems using bark, sawdust and sanderdust. The new generating facilities, scheduled to go online next year, will save an additional half-million barrels of oil a year. The company is already looking at new ways to further reduce its dependence on nonrenewable energy sources. One promising technology is wood gasification.

  13. Performance tests of 4-5 year old lithium sulphur dioxide batteries

    NASA Astrophysics Data System (ADS)

    Holland, C. R.; Williams, R. L.

    1983-09-01

    Tests of a new acoustic system in the spring of 1982, using radio frequency transmission of the data, required the Naval Ocean Research and Development Activity (NORDA) to reconsider the use of lithium battery technology. A request was made to the Navy Safety Office, Naval Sea Systems Command Code 06H, for permission to utilize lithium batteries in the R&D project and for permission to use existing lithium sulphur dioxide cells, which had been purchased in previous years. The safety office tentatively approved the intended useage but subject to a performance test and evaluation of a representative sample of the existing cells. In response to the NAVSEA direction, 32 cells were randomly chosen and subjected to forming and discharge tests. The cells, as a group, performed beyond expectations and provided energy in excess of the manufacturer's original specifications for these cells. All tests were performed without safety problems or any incidents. Similar cells from the same lot were subsequently used at sea in the R&D project and performed equally as well as those tested in the laboratory. This report documents the testing procedures used to evaluate 4 to 5 year old Li/SO2 cells and the test results achieved.

  14. Baseline Characteristics of the Infant Aphakia Treatment Study Population: Predicting Recognition Acuity at 4.5 Years of Age

    PubMed Central

    Hartmann, E. Eugenie; Lynn, Michael J.; Lambert, Scott R.

    2015-01-01

    Purpose. To identify patient baseline characteristics that predict recognition acuity at 4.5 years of age in the Infant Aphakia Treatment Study, a study of patients with monocular infantile cataracts. Methods. We analyzed baseline characteristics of the 114 infants enrolled in the Infant Aphakia Treatment Study to determine which were most predictive of visual outcome at 4.5 years of age. All infants underwent cataract surgery between 1 and 7 months of age. Monocular acuity was assessed at 4.5 years of age by a traveling examiner using the Amblyopia Treatment Study HOTV protocol. Results. Age at cataract surgery was weakly associated with visual acuity (Spearman rank correlation coefficient = 0.19, P = 0.041) with median visual acuity better among the younger patients (28–48 days: 0.50 logMAR, 49–210 days: 1.10 logMAR, P = 0.046). Patients from families with private insurance had significantly better median visual acuity (0.60 vs. 1.40 logMAR, P = 0.0004). No other baseline characteristic revealed a significant bivariate relationship with visual acuity. A multiple linear regression relating visual acuity to all baseline characteristics demonstrated that only the availability of private insurance was statistically significant, accounting for 12% of the variance. Conclusions. This analysis concurs with previous studies that early surgery is important for good visual outcomes in patients with unilateral infantile cataracts. The fact that only one baseline variable (private insurance) contributed to the multivariate analysis, accounting for 12% of the variance, suggests that predicting visual outcome for these patients is complicated at best, and cannot be estimated from baseline characteristics alone. (ClinicalTrials.gov number, NCT00212134.) PMID:25503455

  15. Characteristics of type I Gaucher disease associated with persistent thrombocytopenia after treatment with imiglucerase for 4-5 years.

    PubMed

    Hollak, Carla E M; Belmatoug, Nadia; Cole, J Alexander; Vom Dahl, Stephan; Deegan, Patrick B; Goldblatt, Jack; Rosenbloom, Barry; van Dussen, Laura; Tylki-Szymańska, Anna; Weinreb, Neal J; Zimran, Ari; Cappellini, Maria Domenica

    2012-08-01

    The characteristics of Gaucher disease (GD) associated with persistent thrombocytopenia despite imiglucerase enzyme therapy in type 1 GD (GD1) were investigated by retrospective analysis of International Collaborative Gaucher Group (ICGG) Registry data. The study involved 1016 GD1 patients with an intact spleen for whom date of diagnosis, therapy initiation, and platelet counts were known, and who received continuous imiglucerase therapy for 4 to 5 years. These patients were stratified by last platelet count: ≥ 120 × 10(9) /l (n = 772); ≥ 100 to <120 × 10(9) /l (n = 94); ≥ 80 to <100 × 10(9) /l (n = 80); and <80 × 10(9) /l (n = 70; 20 with <60 × 10(9) /l) and characterized by initial and cumulative average imiglucerase dose, body mass index, platelet count, anaemia, hepatomegaly, splenomegaly, and skeletal assessments at baseline and after 4-5 years of therapy. Statistically significant associations were found between persistent thrombocytopenia and baseline platelet count (<80 × 10(9) /l), splenomegaly, and anaemia (all P < 0·0001). After 4-5 years, statistically significant associations were found with splenomegaly (P < 0·0001), anaemia (P < 0·0001), white blood cell count (P = 0·049), hepatomegaly (P = 0·004) and bone pain (P = 0·035). Exponential platelet decay in relation to splenomegaly suggests that platelets increase only when spleen volume decreases substantially. PMID:22640238

  16. 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.

  17. 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.

  18. 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.

  19. Three million years of monsoon variability over the northern Sahara

    NASA Astrophysics Data System (ADS)

    Larrasoana, J. C.; Roberts, A. P.; Rohling, E. J.; Winklhofer, M.; Wehausen, R.

    2003-04-01

    We present a 3 million-year record of aeolian dust supply into the eastern Mediterranean Sea, based on hematite contents derived from magnetic properties of sediments form ODP Site 967. Our record has an average temporal resolution of ˜400~years. We deduce that the aeolian hematite in eastern Mediterranean sediments derived from eastern Algerian, Libyan, and western Egyptian lowlands located north of the central Saharan watershed (˜21o~N). We relate dust-flux minima to penetration of the African summer monsoon front to the north of the central Saharan watershed. This would have enhanced soil humidity and vegetation cover in the source regions, in agreement with results from "green Sahara" climate models. Our results indicate that this northward monsoon penetration occured pervasively during insolation maxima throughout the last 3 million years. As would be expected, this orbital precession-scale mechanism is modulated on both short (95 kyr) and long (406 kyr) eccentricity time scales. We also observe a strong expression of the 41-kyr obliquity cycle. There is a marked increase in sub-Milankovitch variability around the Mid-Pleistocene transition (˜0.95~Ma), which suggests a link between millennial-scale variability, including monsoon dynamics, and the size of the northern hemisphere ice sheets.

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

    PubMed

    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.

  1. 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

  2. A 40-million-year history of atmospheric CO(2).

    PubMed

    Zhang, Yi Ge; Pagani, Mark; Liu, Zhonghui; Bohaty, Steven M; Deconto, Robert

    2013-10-28

    The alkenone-pCO2 methodology has been used to reconstruct the partial pressure of ancient atmospheric carbon dioxide (pCO2) for the past 45 million years of Earth's history (Middle Eocene to Pleistocene epochs). The present long-term CO2 record is a composite of data from multiple ocean localities that express a wide range of oceanographic and algal growth conditions that potentially bias CO2 results. In this study, we present a pCO2 record spanning the past 40 million years from a single marine locality, Ocean Drilling Program Site 925 located in the western equatorial Atlantic Ocean. The trends and absolute values of our new CO2 record site are broadly consistent with previously published multi-site alkenone-CO2 results. However, new pCO2 estimates for the Middle Miocene are notably higher than published records, with average pCO2 concentrations in the range of 400-500 ppm. Our results are generally consistent with recent pCO2 estimates based on boron isotope-pH data and stomatal index records, and suggest that CO2 levels were highest during a period of global warmth associated with the Middle Miocene Climatic Optimum (17-14 million years ago, Ma), followed by a decline in CO2 during the Middle Miocene Climate Transition (approx. 14 Ma). Several relationships remain contrary to expectations. For example, benthic foraminiferal δ(18)O records suggest a period of deglaciation and/or high-latitude warming during the latest Oligocene (27-23 Ma) that, based on our results, occurred concurrently with a long-term decrease in CO2 levels. Additionally, a large positive δ(18)O excursion near the Oligocene-Miocene boundary (the Mi-1 event, approx. 23 Ma), assumed to represent a period of glacial advance and retreat on Antarctica, is difficult to explain by our CO2 record alone given what is known of Antarctic ice sheet history and the strong hysteresis of the East Antarctic Ice Sheet once it has grown to continental dimensions. We also demonstrate that in the

  3. 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.

  4. 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.

  5. Nearly 10 Million U.S. Adults Considered Suicide Last Year

    MedlinePlus

    ... 160979.html Nearly 10 Million U.S. Adults Considered Suicide Last Year Rates at historically high levels -- up ... 10 million U.S. adults seriously thought about committing suicide last year, federal health officials reported Thursday. Rates ...

  6. Atmospheric carbon dioxide concentrations over the past 60 million years.

    PubMed

    Pearson, P N; Palmer, M R

    2000-08-17

    Knowledge of the evolution of atmospheric carbon dioxide concentrations throughout the Earth's history is important for a reconstruction of the links between climate and radiative forcing of the Earth's surface temperatures. Although atmospheric carbon dioxide concentrations in the early Cenozoic era (about 60 Myr ago) are widely believed to have been higher than at present, there is disagreement regarding the exact carbon dioxide levels, the timing of the decline and the mechanisms that are most important for the control of CO2 concentrations over geological timescales. Here we use the boron-isotope ratios of ancient planktonic foraminifer shells to estimate the pH of surface-layer sea water throughout the past 60 million years, which can be used to reconstruct atmospheric CO2 concentrations. We estimate CO2 concentrations of more than 2,000 p.p.m. for the late Palaeocene and earliest Eocene periods (from about 60 to 52 Myr ago), and find an erratic decline between 55 and 40 Myr ago that may have been caused by reduced CO2 outgassing from ocean ridges, volcanoes and metamorphic belts and increased carbon burial. Since the early Miocene (about 24 Myr ago), atmospheric CO2 concentrations appear to have remained below 500 p.p.m. and were more stable than before, although transient intervals of CO2 reduction may have occurred during periods of rapid cooling approximately 15 and 3 Myr ago.

  7. 470-Million-year-old black corals from China

    NASA Astrophysics Data System (ADS)

    Baliński, Andrzej; Sun, Yuanlin; Dzik, Jerzy

    2012-08-01

    Phosphatic (possibly secondarily phosphatised) remains of antipatharian coralla, previously unknown in the fossil record, occur abundantly in the early Ordovician Fenxiang Formation in the Hubei Province, southern China. Probably two species (and genera) are represented, which differ in spinosity of branches. The more spinose one, Sinopathes reptans, has its lateral spines bearing regular, longitudinally arranged costellae. The early Floian geological age of this finding, about 470 Ma, supports predictions on the timing of anthozoan phylogeny derived from the molecular phylogenetic evidence. Black corals (Antipatharia) are basal to the scleractinians in the Hexacorallia clade, being more derived than sea anemones and the Zoantharia. Based on calibration of the molecular clock with Mesozoic data, the first split of lineages within the scleractinian hexacorals was proposed to take place approximately 425 million years ago. This implies that the origin of Antipatharia should precede this date. They have not been known in the fossil record because of unmineralised skeleton composed primarily of laminar chitin complexed with a protein. Unlike all recent species, the encrusting basal part of the colony dominated in the Ordovician ones and only occasionally erect branches developed, rather chaotically ramified. This presumably plesiomorphic trait seems consistent with ancient geological age and suggests that some problematic fossils from the Late Cambrian may be their, even less-derived, relatives.

  8. 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.

  9. 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.

  10. 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. PMID:20237472

  11. Depression Strikes Nearly 3 Million U.S. Teens a Year

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159763.html Depression Strikes Nearly 3 Million U.S. Teens a Year ... million U.S. teens suffered a major bout of depression, a new government report shows. "Adolescence is a ...

  12. 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…

  13. Father-Child Interaction: Associations with Self-Control and Aggression among 4.5-Year-Olds

    ERIC Educational Resources Information Center

    Meece, Darrell; Robinson, Cheryl Malone

    2014-01-01

    Examined correlates of positive father caregiving and harsh control among 721 (350 girls) four-year-old children through analysis of NICHD Study of Early Child Care data and 7050 (3450 girls) four-year-old children through analysis of Early Childhood Longitudinal Study-Birth Cohort data. Findings from both samples suggest that, for both boys and…

  14. Genetic Influences in Different Aspects of Language Development: The Etiology of Language Skills in 4.5-Year-Old Twins

    ERIC Educational Resources Information Center

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

    2005-01-01

    The genetic and environmental etiologies of diverse aspects of language ability and disability, including articulation, phonology, grammar, vocabulary, and verbal memory, were investigated in a U.K. sample of 787 pairs of 4.5-year-old same-sex and opposite-sex twins. Moderate genetic influence was found for all aspects of language in the normal…

  15. ENERGY EXPENDITURE AND INTAKE COMPARISONS IN CHILEAN CHILDREN 4-5 YEARS ATTENDING DAY-CARE CENTRES.

    PubMed

    Salazar, Gabriela; Vásquez, Fabián; Rodríguez, Maria P; Andrade, Ana M; Anziani, Maria A; Vio, Fernando; Coward, Williams

    2015-09-01

    Introducción: el método del agua doblemente marcada (ADM) tiene una precisión del 1% y en un mismo sujeto es de 5-8%, dependiendo de la edad y el entorno del sujeto. La evaluación de la ingesta energética es propensa a errores (> 15-20%), dependiendo del método utilizado. Objetivo: cuantificar los errores metodológicos del ADM en niños de 4-5 años que podrían afectar la comparación con la ingesta de energía. Métodos: el gasto de energía (GTE, por ADM), se evaluó durante 14 días en 18 preescolares, asistentes a guarderías infantiles. La ingesta energética se determinó mediante un método combinado: pesaje de alimentos durante los días de la semana y registro después de salir del centro (17 horas en adelante), además de un recordatorio de 24 horas, durante un día del fin de semana. Resultados: el promedio individual del gasto energético total fue 1373 ± 177 kcal y la ingesta de energía (1409 ± 161 kcal). La diferencia global entre la ingesta y el gasto fue 42,9 kcal/día. El error de medición del GET explicó una variación del 2,4%, entre ambas mediciones, y el espacio de dilución de isótopos fue 1030 ± 0.010, confirmando el valor utilizado en los estudios de adultos. Conclusiones: los datos de GET fueron similares a otros estudios realizados en niños en edad preescolar. La pequeña diferencia encontrada entre la ingesta y el gasto energético se puede atribuir a la metodología de la ingesta de energía aplicada, la dieta homogénea en los centros de atención, durante los días de la semana, y el bajo error metodológico del ADM.

  16. Extensive 200-million-year-Old continental flood basalts of the central atlantic magmatic province

    PubMed

    Marzoli; Renne; Piccirillo; Ernesto; Bellieni; De Min A

    1999-04-23

    The Central Atlantic Magmatic Province (CAMP) is defined by tholeiitic basalts that crop out in once-contiguous parts of North America, Europe, Africa, and South America and is associated with the breakup of Pangea. 40Ar/39Ar and paleomagnetic data indicate that CAMP magmatism extended over an area of 2.5 million square kilometers in north and central Brazil, and the total aerial extent of the magmatism exceeded 7 million square kilometers in a few million years, with peak activity at 200 million years ago. The magmatism coincided closely in time with a major mass extinction at the Triassic-Jurassic boundary.

  17. Extensive 200-million-year-Old continental flood basalts of the central atlantic magmatic province

    PubMed

    Marzoli; Renne; Piccirillo; Ernesto; Bellieni; De Min A

    1999-04-23

    The Central Atlantic Magmatic Province (CAMP) is defined by tholeiitic basalts that crop out in once-contiguous parts of North America, Europe, Africa, and South America and is associated with the breakup of Pangea. 40Ar/39Ar and paleomagnetic data indicate that CAMP magmatism extended over an area of 2.5 million square kilometers in north and central Brazil, and the total aerial extent of the magmatism exceeded 7 million square kilometers in a few million years, with peak activity at 200 million years ago. The magmatism coincided closely in time with a major mass extinction at the Triassic-Jurassic boundary. PMID:10213679

  18. Almost 2 Million U.S. Kids Get Concussions a Year

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_159465.html Almost 2 Million U.S. Kids Get Concussions a Year: Study ... MONDAY, June 20, 2016 (HealthDay News) -- Close to 2 million U.S. children and teens may suffer concussions ...

  19. 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.

  20. Ice elevation and erosion rates over the past 10 million years from the interior of West Antarctica.

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.; Ackert, R. P.; Pope, A.

    2008-12-01

    The West Antarctic Ice Sheet (WAIS), the only marine-based ice sheet, is susceptible to rapid collapse in response to increasing air and sea temperatures. Remote sensing and satellite based altimetry indicate rapid thinning and retreat of many outlet glaciers. However, the present day net mass balance of the WAIS remains uncertain. Geologic evidence can be utilized to probe the past behavior of the WAIS in order to better understand its response to global warming. We will present cosmogenic 21Ne and 10Be data in bedrock surfaces from the Ohio Range, part of the Transantarctic Mountains and located near the present day ice divide of the WAIS. Our cosmogenic data provides the first constraints on the long-term history of the ice sheet from the interior of the continent. We find that ice elevation over the past 10 million years in the interior of West Antarctica never exceeded 150m above present day ice levels. In addition, surfaces only 35 m above present day ice levels have suffered no prolonged ice cover over the past 4-5 million years. We find that compared to the past 5 million years, interior ice elevations were at its highest level during the last glaciation. This observation supports the hypothesis that decreasing temperatures since the Pliocene led to a decrease in basal slip and consequent increase in ice elevations. Finally, the cosmogenic 21Ne and 10Be data constrain erosion rates in the granite and sandstone bedrocks from the Ohio Range to between 0.09 m/Myrs to 0.35 m/Myrs over the past 10 million years. These erosion rates from the interior of the continent are extremely low, but comparable to those from the Antarctic Dry Valleys over the same time period. Therefore, a stable landform has existed over a large area of the Antarctic continent since the Late Miocene, probably because of a persistent cold hyperarid climate.

  1. 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.

  2. Dynamic stabilization for L4-5 spondylolisthesis: comparison with minimally invasive transforaminal lumbar interbody fusion with more than 2 years of follow-up.

    PubMed

    Kuo, Chao-Hung; Chang, Peng-Yuan; Wu, Jau-Ching; Chang, Hsuan-Kan; Fay, Li-Yu; Tu, Tsung-Hsi; Cheng, Henrich; Huang, Wen-Cheng

    2016-01-01

    OBJECTIVE In the past decade, dynamic stabilization has been an emerging option of surgical treatment for lumbar spondylosis. However, the application of this dynamic construct for mild spondylolisthesis and its clinical outcomes remain uncertain. This study aimed to compare the outcomes of Dynesys dynamic stabilization (DDS) with minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for the management of single-level spondylolisthesis at L4-5. METHODS This study retrospectively reviewed 91 consecutive patients with Meyerding Grade I spondylolisthesis at L4-5 who were managed with surgery. Patients were divided into 2 groups: DDS and MI-TLIF. The DDS group was composed of patients who underwent standard laminectomy and the DDS system. The MI-TLIF group was composed of patients who underwent MI-TLIF. Clinical outcomes were evaluated by visual analog scale for back and leg pain, Oswestry Disability Index, and Japanese Orthopaedic Association scores at each time point of evaluation. Evaluations included radiographs and CT scans for every patient for 2 years after surgery. RESULTS A total of 86 patients with L4-5 spondylolisthesis completed the follow-up of more than 2 years and were included in the analysis (follow-up rate of 94.5%). There were 64 patients in the DDS group and 22 patients in the MI-TLIF group, and the overall mean follow-up was 32.7 months. Between the 2 groups, there were no differences in demographic data (e.g., age, sex, and body mass index) or preoperative clinical evaluations (e.g., visual analog scale back and leg pain, Oswestry Disability Index, and Japanese Orthopaedic Association scores). The mean estimated blood loss of the MI-TLIF group was lower, whereas the operation time was longer compared with the DDS group (both p < 0.001). For both groups, clinical outcomes were significantly improved at 6, 12, 18, and 24 months after surgery compared with preoperative clinical status. Moreover, there were no differences between the 2

  3. A 26-Year-Old Female with Systemic Mastocytosis with Associated Myeloid Neoplasm with Eosinophilia and Abnormalities of PDGFRB, t(4;5)(q21;q33).

    PubMed

    Brown, Laura E; Zhang, Da; Persons, Diane L; Yacoub, Abdulraheem; Ponnala, Shivani; Cui, Wei

    2016-01-01

    Various translocations involving the PDGFRB gene are identified in myeloid neoplasms. However, the PRKG2/PDGFRB fusion gene associated with t(4;5)(q21;q33) has previously been reported in only 3 patients. We present the case of a 26-year-old woman with microcytic anemia, basophilia, thrombocytosis, and massive splenomegaly, who was found to have systemic mastocytosis and associated clonal hematological non-mast cell lineage disease (SM-AHNMD), with myeloid neoplasm with PRKG2/PDGFRB rearrangement. Initial findings included basophilia (37%, 4.1 k/μL), hypercellular marrow with eosinophilia, and increased and atypical megakaryocytes, suggestive of myeloproliferative neoplasm. Additional studies revealed large clusters of CD25 positive mast cells, fulfilling the criteria for the diagnosis of systemic mastocytosis. Consistent with prior reports of this translocation, our patient has responded well to imatinib. This case, in conjunction with others in the literature, suggests a possible connection between t(4;5)(q21;q33) PRKG2/PDGFRB and systemic mastocytosis and highlights their favorable response to imatinib. PMID:27648315

  4. A 26-Year-Old Female with Systemic Mastocytosis with Associated Myeloid Neoplasm with Eosinophilia and Abnormalities of PDGFRB, t(4;5)(q21;q33)

    PubMed Central

    Persons, Diane L.; Ponnala, Shivani

    2016-01-01

    Various translocations involving the PDGFRB gene are identified in myeloid neoplasms. However, the PRKG2/PDGFRB fusion gene associated with t(4;5)(q21;q33) has previously been reported in only 3 patients. We present the case of a 26-year-old woman with microcytic anemia, basophilia, thrombocytosis, and massive splenomegaly, who was found to have systemic mastocytosis and associated clonal hematological non-mast cell lineage disease (SM-AHNMD), with myeloid neoplasm with PRKG2/PDGFRB rearrangement. Initial findings included basophilia (37%, 4.1 k/μL), hypercellular marrow with eosinophilia, and increased and atypical megakaryocytes, suggestive of myeloproliferative neoplasm. Additional studies revealed large clusters of CD25 positive mast cells, fulfilling the criteria for the diagnosis of systemic mastocytosis. Consistent with prior reports of this translocation, our patient has responded well to imatinib. This case, in conjunction with others in the literature, suggests a possible connection between t(4;5)(q21;q33) PRKG2/PDGFRB and systemic mastocytosis and highlights their favorable response to imatinib. PMID:27648315

  5. 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.

  6. Developmental change in the acuity of the "Number Sense": The Approximate Number System in 3-, 4-, 5-, and 6-year-olds and adults.

    PubMed

    Halberda, Justin; Feigenson, Lisa

    2008-09-01

    Behavioral, neuropsychological, and brain imaging research points to a dedicated system for processing number that is shared across development and across species. This foundational Approximate Number System (ANS) operates over multiple modalities, forming representations of the number of objects, sounds, or events in a scene. This system is imprecise and hence differs from exact counting. Evidence suggests that the resolution of the ANS, as specified by a Weber fraction, increases with age such that adults can discriminate numerosities that infants cannot. However, the Weber fraction has yet to be determined for participants of any age between 9 months and adulthood, leaving its developmental trajectory unclear. Here we identify the Weber fraction of the ANS in 3-, 4-, 5-, and 6-year-old children and in adults. We show that the resolution of this system continues to increase throughout childhood, with adultlike levels of acuity attained surprisingly late in development. PMID:18793076

  7. Long-Term Effects of the Life Skills Program IPSY on Substance Use: Results of a 4.5-Year Longitudinal Study.

    PubMed

    Weichold, Karina; Blumenthal, Anja

    2016-01-01

    This study investigated the long-term effectiveness of a Life Skills program with regard to use and proneness to legal and illicit drug use across a 4.5-year study interval. The universal school-based Life Skills program IPSY (Information + Psychosocial Competence = Protection) against adolescent substance use was implemented over 3 years (basic program in grade 5 and booster sessions in grades 6 and 7). Over the same time period, it was evaluated based on a longitudinal quasi-experimental design with intervention and control group, including two follow-up assessments after program completion [six measurement points; N (T1) = 1657 German students; M age (T1) = 10.5 years]. Applying an HLM approach, results showed that participation in IPSY had a significant effect on the frequency of smoking, and proneness to illicit drug use, across the entire study period. In addition, shorter-term effects were found for the frequency of alcohol use in that intervention effects were evident until the end of program implementation but diminished 2 years later. Thus, IPSY can be deemed an effective intervention against tobacco use and proneness to and use of illicit drugs during adolescence; however, further booster sessions may be necessary in later adolescence to enhance youths' resistance skills when alcohol use becomes highly normative among peers. PMID:26202801

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Aerobic microbial respiration in 86-million-year-old deep-sea red clay.

    PubMed

    Røy, Hans; Kallmeyer, Jens; Adhikari, Rishi Ram; Pockalny, Robert; Jørgensen, Bo Barker; D'Hondt, Steven

    2012-05-18

    Microbial communities can subsist at depth in marine sediments without fresh supply of organic matter for millions of years. At threshold sedimentation rates of 1 millimeter per 1000 years, the low rates of microbial community metabolism in the North Pacific Gyre allow sediments to remain oxygenated tens of meters below the sea floor. We found that the oxygen respiration rates dropped from 10 micromoles of O(2) liter(-1) year(-1) near the sediment-water interface to 0.001 micromoles of O(2) liter(-1) year(-1) at 30-meter depth within 86 million-year-old sediment. The cell-specific respiration rate decreased with depth but stabilized at around 10(-3) femtomoles of O(2) cell(-1) day(-1) 10 meters below the seafloor. This result indicated that the community size is controlled by the rate of carbon oxidation and thereby by the low available energy flux. PMID:22605778

  13. Reorganization of the western Himalayan river system after five million years ago.

    PubMed

    Clift, Peter D; Blusztajn, Jerzy

    2005-12-15

    Uplift of mountains driven by tectonic forces can influence regional climate as well as regional drainage patterns, which in turn control the discharge of eroded sediment to the ocean. But the nature of the interactions between tectonic forces, climate and drainage evolution remains contested. Here we reconstruct the erosional discharge from the Indus river over the past 30 million years using seismic reflection data obtained from drill core samples from the Arabian Sea and neodymium isotope data. We find that the source of the Indus sediments was dominated by erosion within and north of the Indus suture zone until five million years ago; after that, the river began to receive more erosional products from Himalayan sources. We propose that this change in the erosional pattern is caused by a rerouting of the major rivers of the Punjab into the Indus, which flowed east into the Ganges river before that time. Seismic reflection profiles from the Indus fan suggest high mass accumulation rates during the Pleistocene epoch partly driven by increased drainage to the Indus river after five million years ago and partly by faster erosion linked to a stronger monsoon over the past four million years. Our isotope stratigraphy for the Indus fan provides strong evidence for a significant change in the geometry of western Himalayan river systems in the recent geologic past.

  14. [Children's health. 40. Unacceptable that 14 million children die every year].

    PubMed

    Bergqvist, L P

    1987-10-01

    The 40th annual report of the UN Children's Emergency Fund (UNICEF) states that about 7 million of the 14 million children who die throughout the world each year could be saved by modern methods of health care and food supply. UNICEF's executive director James Grant points out that 40 years ago little international attention was given to mass death from starvation, but today any such crisis attracts the mass media, and people and governments act to avoid mass death. Undernourishment and epidemics continue to threaten the world's children and more than 280,000 children die from these causes each week. Even with the crises of the past two years in Africa there have been more deaths among children in India and Pakistan than in all of Africa's 46 countries together. Existing knowledge on cheap methods of improving the health of children in underdeveloped countries is sufficient to save at least 7 million children's lives each year. Many millions more could have a normal growth with better information on replacements on mother's milk, vaccinations and access to supplies of water, sugar, and salt for oral rehydration therapy. Just as important are the new technologies of the communications revolution which is taking place in underdeveloped countries. Most homes have a radio, and televisions are available in most villages and in many small communities there are schools and health workers.

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

    PubMed

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

    2012-10-01

    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. PMID:22738438

  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

    2011-08-18

    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. Global motion perception is independent from contrast sensitivity for coherent motion direction discrimination and visual acuity in 4.5-year-old children

    PubMed Central

    Chakraborty, Arijit; Anstice, Nicola S.; Jacobs, Robert J.; Paudel, Nabin; LaGasse, Linda L.; Lester, Barry M.; Wouldes, Trecia A.; Harding, Jane E.; Thompson, Benjamin

    2015-01-01

    Global motion processing depends on a network of brain regions that includes extrastriate area V5 in the dorsal visual stream. For this reason, psychophysical measures of global motion perception have been used to provide a behavioural measure of dorsal stream function. This approach assumes that global motion is relatively independent of visual functions that arise earlier in the visual processing hierarchy such as contrast sensitivity and visual acuity. We tested this assumption by assessing the relationships between global motion perception, contrast sensitivity for coherent motion direction discrimination (henceforth referred to as contrast sensitivity) and habitual visual acuity in a large group of 4.5-year-old children (n = 117). The children were born at risk of abnormal neurodevelopment because of prenatal drug exposure or risk factors for neonatal hypoglycaemia. Motion coherence thresholds, a measure of global motion perception, were assessed using random dot kinematograms. The contrast of the stimuli was fixed at 100% and coherence was varied. Contrast sensitivity was measured using the same stimuli by fixing motion coherence at 100% and varying dot contrast. Stereoacuity was also measured. Motion coherence thresholds were not correlated with contrast sensitivity or visual acuity. However, lower (better) motion coherence thresholds were correlated with finer stereoacuity (rho=0.38, p=0.004). Contrast sensitivity and visual acuity were also correlated (rho= −0.26, p=0.004) with each other. These results indicate that global motion perception for high contrast stimuli is independent of contrast sensitivity and visual acuity and can be used to assess motion integration mechanisms in children. PMID:26318529

  18. Time use differences in activity participation among children 4-5 years old with and without the risk of developing conduct problems.

    PubMed

    Yu, Mong-Lin; Ziviani, Jenny; Baxter, Janeen; Haynes, Michele

    2012-01-01

    Conduct problems in childhood are associated with the way in which children engage in daily activities. Research, to date, on conduct problems in relation to time use has primarily focused on school aged children and their participation in discrete activities such as watching TV and sport. The purpose of the present study is to determine if children at risk of developing conduct problems have different activity patterns compared to those not at risk. Specifically aspects of time use which concern involvement in activities that provide physical exertion, structure, rest and social engagement were examined. Data for this investigation were drawn from the Longitudinal Study of Australian Children (Wave 1) and focused on 4936 children aged 4-5 years. Findings indicate that children at risk of developing conduct problems spend significantly more time in: physical activities such as "riding a bike", and "in the company of adults only" than children not at risk of developing conduct problems but less time "with peers under adult supervision". Gender differences were also found in the same activities with boys participating in more "bike riding" and activities "without peers under adult supervision" than girls. Young children generally participated in more physical activities and spend more time "with peers while supervised by adults" on weekend days, and more time in "structured activities" and "in the company of adults only" on weekdays. These findings are discussed in respect of the potentially risky nature of physical activity choice and the contribution of adult supervision in the context of peer group participation for children at risk of developing conduct problems.

  19. Climate sensitivity constrained by CO2 concentrations over the past 420 million years.

    PubMed

    Royer, Dana L; Berner, Robert A; Park, Jeffrey

    2007-03-29

    A firm understanding of the relationship between atmospheric carbon dioxide concentration and temperature is critical for interpreting past climate change and for predicting future climate change. A recent synthesis suggests that the increase in global-mean surface temperature in response to a doubling of the atmospheric carbon dioxide concentration, termed 'climate sensitivity', is between 1.5 and 6.2 degrees C (5-95 per cent likelihood range), but some evidence is inconsistent with this range. Moreover, most estimates of climate sensitivity are based on records of climate change over the past few decades to thousands of years, when carbon dioxide concentrations and global temperatures were similar to or lower than today, so such calculations tend to underestimate the magnitude of large climate-change events and may not be applicable to climate change under warmer conditions in the future. Here we estimate long-term equilibrium climate sensitivity by modelling carbon dioxide concentrations over the past 420 million years and comparing our calculations with a proxy record. Our estimates are broadly consistent with estimates based on short-term climate records, and indicate that a weak radiative forcing by carbon dioxide is highly unlikely on multi-million-year timescales. We conclude that a climate sensitivity greater than 1.5 degrees C has probably been a robust feature of the Earth's climate system over the past 420 million years, regardless of temporal scaling.

  20. 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.

  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. PMID:24631241

  3. 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.

  4. A tropical rainforest in Colorado 1.4 million years after the Cretaceous-Tertiary boundary.

    PubMed

    Johnson, Kirk R; Ellis, Beth

    2002-06-28

    An extremely diverse lower Paleocene (64.1 million years ago) fossil leaf site from Castle Rock, Colorado, contains fossil litter that is similar to the litter of extant equatorial rainforests. The presence of a high-diversity tropical rainforest is unexpected, because other Paleocene floras are species-poor, a feature generally attributed to the Cretaceous-Tertiary (K-T) extinction. The site occurs on the margin of the Denver Basin in synorogenic sedimentary rocks associated with the rise of the Laramide Front Range. Orographic conditions caused by local topography, combined with equable climate, appear to have allowed for the establishment of rainforests within 1.4 million years of the K-T boundary.

  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. 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.

  7. Conservation of plastid sequences in the plant nuclear genome for millions of years facilitates endosymbiotic evolution.

    PubMed

    Rousseau-Gueutin, Mathieu; Ayliffe, Michael A; Timmis, Jeremy N

    2011-12-01

    The nuclear genome of eukaryotes contains large amounts of cytoplasmic organelle DNA (nuclear integrants of organelle DNA [norgs]). The recent sequencing of many mitochondrial and chloroplast genomes has enabled investigation of the potential role of norgs in endosymbiotic evolution. In this article, we describe a new polymerase chain reaction-based method that allows the identification and evolutionary study of recent and older norgs in a range of eukaryotes. We tested this method in the genus Nicotiana and obtained sequences from seven nuclear integrants of plastid DNA (nupts) totaling 25 kb in length. These nupts were estimated to have been transferred 0.033 to 5.81 million years ago. The spectrum of mutations present in the potential protein-coding sequences compared with the noncoding sequences of each nupt revealed that nupts evolve in a nuclear-specific manner and are under neutral evolution. Indels were more frequent in noncoding regions than in potential coding sequences of former chloroplastic DNA, most probably due to the presence of a higher number of homopolymeric sequences. Unexpectedly, some potential protein-coding sequences within the nupts still contained intact open reading frames for up to 5.81 million years. These results suggest that chloroplast genes transferred to the nucleus have in some cases several millions of years to acquire nuclear regulatory elements and become functional. The different factors influencing this time frame and the potential role of nupts in endosymbiotic gene transfer are discussed.

  8. 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.

  9. Filamentous microfossils in a 3,235-million-year-old volcanogenic massive sulphide deposit.

    PubMed

    Rasmussen, B

    2000-06-01

    The record of Archaean microfossils is sparse. Of the few bona fide fossil assemblages, most are from shallow-water settings, and they are typically associated with laminated, stromatolitic sedimentary rocks. Microfossils from deep-sea hydrothermal systems have not been reported in Precambrian rocks (> 544 million years old), although thermophilic microbes are ubiquitous in modern sea-floor hydrothermal settings, and apparently have the most ancient lineages. Here, I report the discovery of pyritic filaments, the probable fossil remains of thread-like microorganisms, in a 3,235-million-year-old deep-sea volcanogenic massive sulphide deposit from the Pilbara Craton of Australia. From their mode of occurrence, the micro-organisms were probably thermophilic chemotropic prokaryotes, which inhabited sub-sea-floor hydrothermal environments. They represent the first fossil evidence for microbial life in a Precambrian submarine thermal spring system, and extend the known range of submarine hydrothermal biota by more than 2,700 million years. Such environments may have hosted the first living systems on Earth, consistent with proposals for a thermophilic origin of life.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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. PMID:24653037

  16. 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

  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. PMID:24519010

  18. 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.

  19. 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.

  20. 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

    2013-01-01

    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

  1. 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.

  2. 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. PMID:17758107

  3. 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.

  4. 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.

  5. Bayesian hierarchical regression analysis of variations in sea surface temperature change over the past million years

    NASA Astrophysics Data System (ADS)

    Snyder, Carolyn W.

    2016-09-01

    Statistical challenges often preclude comparisons among different sea surface temperature (SST) reconstructions over the past million years. Inadequate consideration of uncertainty can result in misinterpretation, overconfidence, and biased conclusions. Here I apply Bayesian hierarchical regressions to analyze local SST responsiveness to climate changes for 54 SST reconstructions from across the globe over the past million years. I develop methods to account for multiple sources of uncertainty, including the quantification of uncertainty introduced from absolute dating into interrecord comparisons. The estimates of local SST responsiveness explain 64% (62% to 77%, 95% interval) of the total variation within each SST reconstruction with a single number. There is remarkable agreement between SST proxy methods, with the exception of Mg/Ca proxy methods estimating muted responses at high latitudes. The Indian Ocean exhibits a muted response in comparison to other oceans. I find a stable estimate of the proposed "universal curve" of change in local SST responsiveness to climate changes as a function of sin2(latitude) over the past 400,000 years: SST change at 45°N/S is larger than the average tropical response by a factor of 1.9 (1.5 to 2.6, 95% interval) and explains 50% (35% to 58%, 95% interval) of the total variation between each SST reconstruction. These uncertainty and statistical methods are well suited for application across paleoclimate and environmental data series intercomparisons.

  6. 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. PMID:26628271

  7. 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.

  8. 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

    2016-02-01

    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. PMID:26776738

  9. 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.

  10. luxS in bacteria isolated from 25- to 40-million-year-old amber.

    PubMed

    Santiago-Rodriguez, Tasha M; Patrício, Ana R; Rivera, Jessica I; Coradin, Mariel; Gonzalez, Alfredo; Tirado, Gabriela; Cano, Raúl J; Toranzos, Gary A

    2014-01-01

    Interspecies bacterial communication is mediated by autoinducer-2, whose synthesis depends on luxS. Due to the apparent universality of luxS (present in more than 40 bacterial species), it may have an ancient origin; however, no direct evidence is currently available. We amplified luxS in bacteria isolated from 25- to 40-million-year-old amber. The phylogenies and molecular clocks of luxS and the 16S rRNA gene from ancient and extant bacteria were determined as well. Luminescence assays using Vibrio harveyi BB170 aimed to determine the activity of luxS. While the phylogeny of luxS was very similar to that of extant Bacillus spp., amber isolates exhibited unique 16S rRNA gene phylogenies. This suggests that luxS may have been acquired by horizontal transfer millions of years ago. Molecular clocks of luxS suggest slow evolutionary rates, similar to those of the 16S rRNA gene and consistent with a conserved gene. Dendograms of the 16S rRNA gene and luxS show two separate clusters for the extant and ancient bacteria, confirming the uniqueness of the latter group.

  11. The dynamics of LTR retrotransposon accumulation across 25 million years of panicoid grass evolution.

    PubMed

    Estep, M C; DeBarry, J D; Bennetzen, J L

    2013-02-01

    Sample sequence analysis was employed to investigate the repetitive DNAs that were most responsible for the evolved variation in genome content across seven panicoid grasses with >5-fold variation in genome size and different histories of polyploidy. In all cases, the most abundant repeats were LTR retrotransposons, but the particular families that had become dominant were found to be different in the Pennisetum, Saccharum, Sorghum and Zea lineages. One element family, Huck, has been very active in all of the studied species over the last few million years. This suggests the transmittal of an active or quiescent autonomous set of Huck elements to this lineage at the founding of the panicoids. Similarly, independent recent activity of Ji and Opie elements in Zea and of Leviathan elements in Sorghum and Saccharum species suggests that members of these families with exceptional activation potential were present in the genome(s) of the founders of these lineages. In a detailed analysis of the Zea lineage, the combined action of several families of LTR retrotransposons were observed to have approximately doubled the genome size of Zea luxurians relative to Zea mays and Zea diploperennis in just the last few million years. One of the LTR retrotransposon amplification bursts in Zea may have been initiated by polyploidy, but the great majority of transposable element activations are not. Instead, the results suggest random activation of a few or many LTR retrotransposons families in particular lineages over evolutionary time, with some families especially prone to future activation and hyper-amplification.

  12. The dynamics of LTR retrotransposon accumulation across 25 million years of panicoid grass evolution

    PubMed Central

    Estep, M C; DeBarry, J D; Bennetzen, J L

    2013-01-01

    Sample sequence analysis was employed to investigate the repetitive DNAs that were most responsible for the evolved variation in genome content across seven panicoid grasses with >5-fold variation in genome size and different histories of polyploidy. In all cases, the most abundant repeats were LTR retrotransposons, but the particular families that had become dominant were found to be different in the Pennisetum, Saccharum, Sorghum and Zea lineages. One element family, Huck, has been very active in all of the studied species over the last few million years. This suggests the transmittal of an active or quiescent autonomous set of Huck elements to this lineage at the founding of the panicoids. Similarly, independent recent activity of Ji and Opie elements in Zea and of Leviathan elements in Sorghum and Saccharum species suggests that members of these families with exceptional activation potential were present in the genome(s) of the founders of these lineages. In a detailed analysis of the Zea lineage, the combined action of several families of LTR retrotransposons were observed to have approximately doubled the genome size of Zea luxurians relative to Zea mays and Zea diploperennis in just the last few million years. One of the LTR retrotransposon amplification bursts in Zea may have been initiated by polyploidy, but the great majority of transposable element activations are not. Instead, the results suggest random activation of a few or many LTR retrotransposons families in particular lineages over evolutionary time, with some families especially prone to future activation and hyper-amplification. PMID:23321774

  13. 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.

  14. 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. PMID:26080428

  15. 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

  16. Sand residence times of one million years in the Namib Sand Sea from cosmogenic nuclides

    NASA Astrophysics Data System (ADS)

    Vermeesch, P.; Fenton, C. R.; Kober, F.; Wiggs, G. F. S.; Bristow, C. S.; Xu, S.

    2010-12-01

    The Namib Sand Sea is one of the world's oldest and largest sand deserts, yet little is known about the source of the sand in this, or other large deserts. In particular, it is unclear whether the sand is derived from local sediment or comes from remote sources. The relatively uniform appearance of dune sands and low compositional variability within dune fields make it difficult to address this question. Here we combine cosmogenic-nuclide measurements and geochronological techniques to assess the provenance and migration history of sand grains in the Namib Sand Sea. We use U-Pb geochronology of detrital zircons to show that the primary source of sand is the Orange River at the southern edge of the Namib desert. Our burial ages obtained from measurements of the cosmogenic nuclides 10Be, 26Al and 21Ne suggest that the residence time of sand within the sand sea is at least one million years. We therefore conclude that, despite large climatic changes in the Namib region associated with Quaternary glacial-interglacial cycles, the area currently occupied by the Namib Sand Sea has never been entirely devoid of sand during the past million years.

  17. 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. PMID:27621451

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

    PubMed Central

    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.

    2015-01-01

    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. PMID:26080428

  19. 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

  20. Two modes of change in Southern Ocean productivity over the past million years.

    PubMed

    Jaccard, S L; Hayes, C T; Martínez-García, A; Hodell, D A; Anderson, R F; Sigman, D M; Haug, G H

    2013-03-22

    Export of organic carbon from surface waters of the Antarctic Zone of the Southern Ocean decreased during the last ice age, coinciding with declining atmospheric carbon dioxide (CO(2)) concentrations, signaling reduced exchange of CO(2) between the ocean interior and the atmosphere. In contrast, in the Subantarctic Zone, export production increased into ice ages coinciding with rising dust fluxes, thus suggesting iron fertilization of subantarctic phytoplankton. Here, a new high-resolution productivity record from the Antarctic Zone is compiled with parallel subantarctic data over the past million years. Together, they fit the view that the combination of these two modes of Southern Ocean change determines the temporal structure of the glacial-interglacial atmospheric CO(2) record, including during the interval of "lukewarm" interglacials between 450 and 800 thousand years ago.

  1. Natural variability of Greenland climate, vegetation, and ice volume during the past million years.

    PubMed

    de Vernal, Anne; Hillaire-Marcel, Claude

    2008-06-20

    The response of the Greenland ice sheet to global warming is a source of concern notably because of its potential contribution to changes in the sea level. We demonstrated the natural vulnerability of the ice sheet by using pollen records from marine sediment off southwest Greenland that indicate important changes of the vegetation in Greenland over the past million years. The vegetation that developed over southern Greenland during the last interglacial period is consistent with model experiments, suggesting a reduced volume of the Greenland ice sheet. Abundant spruce pollen indicates that boreal coniferous forest developed some 400,000 years ago during the "warm" interval of marine isotope stage 11, providing a time frame for the development and decline of boreal ecosystems over a nearly ice-free Greenland. PMID:18566284

  2. 3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya.

    PubMed

    Harmand, Sonia; Lewis, Jason E; Feibel, Craig S; Lepre, Christopher J; Prat, Sandrine; Lenoble, Arnaud; Boës, Xavier; Quinn, Rhonda L; Brenet, Michel; Arroyo, Adrian; Taylor, Nicholas; Clément, Sophie; Daver, Guillaume; Brugal, Jean-Philip; Leakey, Louise; Mortlock, Richard A; Wright, James D; Lokorodi, Sammy; Kirwa, Christopher; Kent, Dennis V; Roche, Hélène

    2015-05-21

    Human evolutionary scholars have long supposed that the earliest stone tools were made by the genus Homo and that this technological development was directly linked to climate change and the spread of savannah grasslands. New fieldwork in West Turkana, Kenya, has identified evidence of much earlier hominin technological behaviour. We report the discovery of Lomekwi 3, a 3.3-million-year-old archaeological site where in situ stone artefacts occur in spatiotemporal association with Pliocene hominin fossils in a wooded palaeoenvironment. The Lomekwi 3 knappers, with a developing understanding of stone's fracture properties, combined core reduction with battering activities. Given the implications of the Lomekwi 3 assemblage for models aiming to converge environmental change, hominin evolution and technological origins, we propose for it the name 'Lomekwian', which predates the Oldowan by 700,000 years and marks a new beginning to the known archaeological record. PMID:25993961

  3. Length of the current interglacial period and interglacial intervals of the last million years

    NASA Astrophysics Data System (ADS)

    Dergachev, V. A.

    2015-12-01

    It was ascertained that the long-term cyclical oscillations of the global climate of the Earth between glacial and interglacial states for the last million years respond to cyclical oscillations of the orbital parameters of the Earth. Cold glacial states with a period of approximately 100 ka give way to shorter intervals of warming of around 10-12 ka long. The current interglacial period—the so-called Holocene—started on Earth roughly 10 ka ago. The length of the current interglacial period and the causes of the climate change over the last approximately 50 years arouse sharp debates connected with the growing anthropogenic emission of greenhouse gases. To estimate the length of the current interglacial period, interglacial intervals near ~400 (MIS-11) and ~800 (MIS-19) ka are analyzed as its probable analogs.

  4. 3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya.

    PubMed

    Harmand, Sonia; Lewis, Jason E; Feibel, Craig S; Lepre, Christopher J; Prat, Sandrine; Lenoble, Arnaud; Boës, Xavier; Quinn, Rhonda L; Brenet, Michel; Arroyo, Adrian; Taylor, Nicholas; Clément, Sophie; Daver, Guillaume; Brugal, Jean-Philip; Leakey, Louise; Mortlock, Richard A; Wright, James D; Lokorodi, Sammy; Kirwa, Christopher; Kent, Dennis V; Roche, Hélène

    2015-05-21

    Human evolutionary scholars have long supposed that the earliest stone tools were made by the genus Homo and that this technological development was directly linked to climate change and the spread of savannah grasslands. New fieldwork in West Turkana, Kenya, has identified evidence of much earlier hominin technological behaviour. We report the discovery of Lomekwi 3, a 3.3-million-year-old archaeological site where in situ stone artefacts occur in spatiotemporal association with Pliocene hominin fossils in a wooded palaeoenvironment. The Lomekwi 3 knappers, with a developing understanding of stone's fracture properties, combined core reduction with battering activities. Given the implications of the Lomekwi 3 assemblage for models aiming to converge environmental change, hominin evolution and technological origins, we propose for it the name 'Lomekwian', which predates the Oldowan by 700,000 years and marks a new beginning to the known archaeological record.

  5. 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. PMID:19097484

  6. Cross-Scale Modelling of Subduction from Minute to Million of Years Time Scale

    NASA Astrophysics Data System (ADS)

    Sobolev, S. V.; Muldashev, I. A.

    2015-12-01

    Subduction is an essentially multi-scale process with time-scales spanning from geological to earthquake scale with the seismic cycle in-between. Modelling of such process constitutes one of the largest challenges in geodynamic modelling today.Here we present a cross-scale thermomechanical model capable of simulating the entire subduction process from rupture (1 min) to geological time (millions of years) that employs elasticity, mineral-physics-constrained non-linear transient viscous rheology and rate-and-state friction plasticity. The model generates spontaneous earthquake sequences. The adaptive time-step algorithm recognizes moment of instability and drops the integration time step to its minimum value of 40 sec during the earthquake. The time step is then gradually increased to its maximal value of 5 yr, following decreasing displacement rates during the postseismic relaxation. Efficient implementation of numerical techniques allows long-term simulations with total time of millions of years. This technique allows to follow in details deformation process during the entire seismic cycle and multiple seismic cycles. We observe various deformation patterns during modelled seismic cycle that are consistent with surface GPS observations and demonstrate that, contrary to the conventional ideas, the postseismic deformation may be controlled by viscoelastic relaxation in the mantle wedge, starting within only a few hours after the great (M>9) earthquakes. Interestingly, in our model an average slip velocity at the fault closely follows hyperbolic decay law. In natural observations, such deformation is interpreted as an afterslip, while in our model it is caused by the viscoelastic relaxation of mantle wedge with viscosity strongly varying with time. We demonstrate that our results are consistent with the postseismic surface displacement after the Great Tohoku Earthquake for the day-to-year time range. We will also present results of the modeling of deformation of the

  7. 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

  8. 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. PMID:23562520

  9. Discovery of some 400 million year-old sensory structures in the compound eyes of trilobites.

    PubMed

    Schoenemann, Brigitte; Clarkson, Euan N K

    2013-01-01

    Fossilised arthropod compound eyes have frequently been described. Among the oldest known are those from the lower Cambrian of the Chengjiang Lagerstätte (China, c 525 Ma). All these compound eyes, though often excellently preserved, however, represent just the outer shells, because soft tissues, or even individual cells, usually do not fossilise. Using modern techniques, including μct-scanning and synchrotron radiation analysis we present the discovery of the sensory cell system of compound eyes, belonging to trilobites around 400 million years old, which allows their description and analysis. They are interpreted as forming part of an apposition-like ommatidium, which is a basic functional type of compound eye present in arthropods of today. Considered in greater detail, it is similar to the compound eye of the horseshoe crab Limulus, generally regarded as a 'living fossil', which probably retained this ancient basal system successfully until today. PMID:23492459

  10. 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

  11. Continuously growing rodent molars result from a predictable quantitative evolutionary change over 50 million years

    PubMed Central

    Mushegyan, Vagan; Eronen, Jussi T.; Lawing, A. Michelle; Sharir, Amnon; Janis, Christine; Jernvall, Jukka; Klein, Ophir D.

    2015-01-01

    Summary The fossil record is widely informative about evolution, but fossils are not systematically used to study the evolution of stem cell-driven renewal. Here, we examined evolution of the continuous growth (hypselodonty) of rodent molar teeth, which is fuelled by the presence of dental stem cells. We studied occurrences of 3500 North American rodent fossils, ranging from 50 million years ago (mya) to 2 mya. We examined changes in molar height to determine if evolution of hypselodonty shows distinct patterns in the fossil record, and we found that hypselodont taxa emerged through intermediate forms of increasing crown height. Next, we designed a Markov simulation model, which replicated molar height increases throughout the Cenozoic, and, moreover, evolution of hypselodonty. Thus, by extension, the retention of the adult stem-cell niche appears to be a predictable quantitative rather than a stochastic qualitative process. Our analyses predict that hypselodonty will eventually become the dominant phenotype. PMID:25921530

  12. 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. PMID:26790001

  13. 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. PMID:25674696

  14. 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.

  15. 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.

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

    PubMed

    Gani, M Royhan; Gani, Nahid D

    2011-01-01

    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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. The Lake Towuti Drilling Project: A New, 1-Million Year Record of Indo-Pacific Hydroclimate

    NASA Astrophysics Data System (ADS)

    Russell, J. M.; Bijaksana, S.; Vogel, H.; Melles, M.; Crowe, S.; Fajar, S. J.; Hasberg, A. K.; Ivory, S.; Kallmeyer, J.; Kelly, C. S.; Kirana, K. H.; Morlock, M.; Tamuntuan, G. H.; Wicaksono, S. A.

    2015-12-01

    ­The Indo-Pacific region plays an integral role in the Earth's climate system. Changes in local insolation, greenhouse gas concentrations, ice volume, and local sea level are each hypothesized to exert a dominant control on Indo-Pacific hydroclimate variations through the Pleistocene, yet existing records from the region are generally short and exhibit fundamental differences in orbital-scale patterns that limit our understanding of the regional climate responses to these global forcings. New paleoclimate records spanning multiple glacial-interglacial cycles are therefore required to document the region's hydroclimatic response to the full range of global climate boundary conditions observed during the late Quaternary. Lake Towuti is located in central Indonesia and is the only known terrestrial sedimentary archive in the region that spans multiple glacial-interglacial cycles. From May - July, 2015, the Towuti Drilling Project, consisting of nearly 40 scientists from eight countries, recovered over 1,000 meters of new sediment core from Lake Towuti. This includes cores though the entire sediment column to bedrock, which likely provide a >1-million-year records of regional hydroclimate. On-site borehole and sediment core logging data document major shifts in sediment composition, including transitions from lake clays to peats, calcareous sediments, and gravels. These data show excellent agreement with major lithological transitions recorded in seismic reflection data, and indicate large changes in lake levels and hydroclimate through the late Quaternary. Prior work on Lake Towuti indicated a dominant control by global ice volume on regional hydroclimate, a hypothesis we aim to test through the analysis of these new cores. This presentation will review existing records from the region and show the first long geochemical and sedimentological records from Lake Towuti to understand orbital-scale hydrologic change during the last ~1 million years.

  3. 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.

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

    PubMed

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

    2005-06-01

    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. PMID:15944701

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

    PubMed Central

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

    2014-01-01

    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. PMID:25253458

  6. 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

  7. 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

  8. Time-varying geomagnetic field models: tools for studying millennial to million year secular variation

    NASA Astrophysics Data System (ADS)

    Constable, Catherine

    2010-05-01

    Global reconstructions of past geomagnetic field behavior draw on community efforts to gather reliable, well-dated paleomagnetic records. The number and spatial distribution of such records is continually improving and a range of model reconstructions have been used to assess temporal variations in geomagnetic dipole moment. On millennial time scales increasingly detailed images of the field are recovered which hint at the recurrence of prominent features like those mapped in the historical field (e.g., high latitude flux lobes and the South Atlantic Magnetic Anomaly). From lower resolution million-year models it is possible to infer the presence, if not the details, of changing non axial-dipole field structures, and to analyze the nature of temporal variations in the axial dipole moment. Such views are inevitably fuzzy representations of the real field, limited in both temporal and spatial resolution. Sharpening the image is desirable, but ongoing efforts to do so will ultimately remain restricted by data distribution, uncertainties, and finite age control. Progress in understanding long term geomagnetic secular variation requires an acute awareness of both limitations and value of such models and an ability to test specific hypotheses rather than relying on the accuracy of the resulting maps. One approach is to analyze a time varying model of a specific paleofield attribute. PADM2M is a recent reconstruction of paleomagnetic axial dipole moment variations for the past 2 million years which shows a persistent asymmetry in the growth and decay of the axial dipole moment on time scales longer than 10 kyr; overall the growth rate for the axial dipole is significantly larger than the decay rate. This feature is not limited to times when the field is reversing, suggesting that the asymmetry may reflect fundamental physical processes underlying the paleosecular variation. The longer decay cycle may suggest periods with a major contribution from diffusive processes

  9. 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

  10. Increasing negativity of age stereotypes across 200 years: evidence from a database of 400 million words.

    PubMed

    Ng, Reuben; Allore, Heather G; Trentalange, Mark; Monin, Joan K; Levy, Becca R

    2015-01-01

    Scholars argue about whether age stereotypes (beliefs about old people) are becoming more negative or positive over time. No previous study has systematically tested the trend of age stereotypes over more than 20 years, due to lack of suitable data. Our aim was to fill this gap by investigating whether age stereotypes have changed over the last two centuries and, if so, what may be associated with this change. We hypothesized that age stereotypes have increased in negativity due, in part, to the increasing medicalization of aging. This study applied computational linguistics to the recently compiled Corpus of Historical American English (COHA), a database of 400 million words that includes a range of printed sources from 1810 to 2009. After generating a comprehensive list of synonyms for the term elderly for these years from two historical thesauri, we identified 100 collocates (words that co-occurred most frequently with these synonyms) for each of the 20 decades. Inclusion criteria for the collocates were: (1) appeared within four words of the elderly synonym, (2) referred to an old person, and (3) had a stronger association with the elderly synonym than other words appearing in the database for that decade. This yielded 13,100 collocates that were rated for negativity and medicalization. We found that age stereotypes have become more negative in a linear way over 200 years. In 1880, age stereotypes switched from being positive to being negative. In addition, support was found for two potential explanations. Medicalization of aging and the growing proportion of the population over the age of 65 were both significantly associated with the increase in negative age stereotypes. The upward trajectory of age-stereotype negativity makes a case for remedial action on a societal level.

  11. Increasing Negativity of Age Stereotypes across 200 Years: Evidence from a Database of 400 Million Words

    PubMed Central

    Ng, Reuben; Allore, Heather G.; Trentalange, Mark; Monin, Joan K.; Levy, Becca R.

    2015-01-01

    Scholars argue about whether age stereotypes (beliefs about old people) are becoming more negative or positive over time. No previous study has systematically tested the trend of age stereotypes over more than 20 years, due to lack of suitable data. Our aim was to fill this gap by investigating whether age stereotypes have changed over the last two centuries and, if so, what may be associated with this change. We hypothesized that age stereotypes have increased in negativity due, in part, to the increasing medicalization of aging. This study applied computational linguistics to the recently compiled Corpus of Historical American English (COHA), a database of 400 million words that includes a range of printed sources from 1810 to 2009. After generating a comprehensive list of synonyms for the term elderly for these years from two historical thesauri, we identified 100 collocates (words that co-occurred most frequently with these synonyms) for each of the 20 decades. Inclusion criteria for the collocates were: (1) appeared within four words of the elderly synonym, (2) referred to an old person, and (3) had a stronger association with the elderly synonym than other words appearing in the database for that decade. This yielded 13,100 collocates that were rated for negativity and medicalization. We found that age stereotypes have become more negative in a linear way over 200 years. In 1880, age stereotypes switched from being positive to being negative. In addition, support was found for two potential explanations. Medicalization of aging and the growing proportion of the population over the age of 65 were both significantly associated with the increase in negative age stereotypes. The upward trajectory of age-stereotype negativity makes a case for remedial action on a societal level. PMID:25675438

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Virtual dissection and lifestyle of a 165 -million-year-old female polychelidan lobster.

    PubMed

    Jauvion, Clément; Audo, Denis; Charbonnier, Sylvain; Vannier, Jean

    2016-03-01

    Polychelidan lobsters are fascinating crustaceans that were known as fossils before being discovered in the deep-sea. They differ from other crustaceans by having four to five pairs of claws. Although recent palaeontological studies have clarified the systematics and phylogeny of the group, the biology of extant polychelidans and--first of all--their anatomy are poorly documented. Numerous aspects of the evolutionary history of the group remain obscure, in particular, how and when polychelidans colonized the deep-sea and became restricted to it. Surprisingly, the biology of extant polychelidans and the anatomy of all species, fossil and recent, are poorly documented. Here, X-ray microtomography (XTM), applied to an exceptionally well-preserved specimen from the La Voulte Lagerstätte, reveals for the first time vital aspects of the external and internal morphology of Voulteryon parvulus (Eryonidae), a 165-million-year-old polychelidan: 1) its mouthparts (maxillae and maxillipeds), 2) its digestive tract and 3) its reproductive organs. Comparisons with dissected specimens clearly identify this specimen as a female with mature ovaries. This set of new information offers new insights into the feeding and reproductive habits of Mesozoic polychelidans. Contrasting with other Jurassic polychelidans that lived in shallow-water environments, V. parvulus spawned in, and probably inhabited, relatively deep-water environments, as do the survivors of the group.

  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. 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.

  20. 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

  1. Conservation of ethylene as a plant hormone over 450 million years of evolution.

    PubMed

    Ju, Chuanli; Van de Poel, Bram; Cooper, Endymion D; Thierer, James H; Gibbons, Theodore R; Delwiche, Charles F; Chang, Caren

    2015-01-08

    Land plants evolved more than 450 million years ago from a lineage of freshwater charophyte green algae(1). The extent to which plant signalling systems existed before the evolutionary transition to land is unknown. Although charophytes occupy a key phylogenetic position for elucidating the origins of such signalling systems(2-4), there is a paucity of sequence data for these organisms(5,6). Here we carry out de novo transcriptomics of five representative charophyte species, and find putative homologues for the biosynthesis, transport, perception and signalling of major plant hormones. Focusing on the plant hormone ethylene, we provide evidence that the filamentous charophyte Spirogyra pratensis possesses an ethylene hormone system homologous to that in plants. Spirogyra produces ethylene and exhibits a cell elongation response to ethylene. Spirogyra ethylene-signalling homologues partially rescue mutants of the angiosperm Arabidopsis thaliana and respond post-translationally to ethylene when expressed in plant cells, indicative of unambiguously homologous ethylene-signalling pathways in Spirogyra and Arabidopsis. These findings imply that the common aquatic ancestor possessed this pathway prior to the colonization of land and that cell elongation was possibly an ancestral ethylene response. This highlights the importance of charophytes for investigating the origins of fundamental plant processes.

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

    PubMed

    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

  3. Cross-amplification and validation of SNPs conserved over 44 million years between seals and dogs.

    PubMed

    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

  4. Neurotrophic activities of trk receptors conserved over 600 million years of evolution.

    PubMed

    Beck, Gad; Munno, David W; Levy, Zehava; Dissel, Helga M; Van-Minnen, Jan; Syed, Naweed I; Fainzilber, Mike

    2004-07-01

    The trk family of receptor tyrosine kinases is crucial for neuronal survival in the vertebrate nervous system, however both C. elegans and Drosophila lack genes encoding trks or their ligands. The only invertebrate representative of this gene family identified to date is Ltrk from the mollusk Lymnaea. Did trophic functions of trk receptors originate early in evolution, or were they an innovation of the vertebrates? Here we show that the Ltrk gene conserves a similar exon/intron order as mammalian trk genes in the region encoding defined extracellular motifs, including one exon encoding a putative variant immunoglobulin-like domain. Chimeric receptors containing the intracellular and transmembrane domains of Ltrk undergo ligand-induced autophosphorylation followed by MAP kinase activation in transfected cells. The chimeras are internalized similarly to TrkA in PC12 cells, and their stimulation leads to differentiation and neurite extension. Knock-down of endogenous Ltrk expression compromises outgrowth and survival of Lymnaea neurons cultured in CNS-conditioned medium. Thus, Ltrk is required for neuronal survival, suggesting that trophic activities of the trk receptor family originated before the divergence of molluscan and vertebrate lineages approximately 600 million years ago.

  5. Forty million years of mutualism: Evidence for Eocene origin of the yucca-yucca moth association

    PubMed Central

    Pellmyr, Olle; Leebens-Mack, James

    1999-01-01

    The obligate mutualism between yuccas and yucca moths is a major model system for the study of coevolving species interactions. Exploration of the processes that have generated current diversity and associations within this mutualism requires robust phylogenies and timelines for both moths and yuccas. Here we establish a molecular clock for the moths based on mtDNA and use it to estimate the time of major life history events within the yucca moths. Colonization of yuccas had occurred by 41.5 ± 9.8 million years ago (Mya), with rapid life history diversification and the emergence of pollinators within 0–6 My after yucca colonization. A subsequent burst of diversification 3.2 ± 1.8 Mya coincided with evolution of arid habitats in western North America. Derived nonpollinating cheater yucca moths evolved 1.26 ± 0.96 Mya. The estimated age of the moths far predates the host fossil record, but is consistent with suggested host age based on paleobotanical, climatological, biogeographical, and geological data, and a tentative estimation from an rbcL-based molecular clock for yuccas. The moth data are used to establish three alternative scenarios of how the moths and plants have coevolved. They yield specific predictions that can be tested once a robust plant phylogeny becomes available. PMID:10430916

  6. 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

  7. Quantitative estimates of changes in marine and terrestrial primary productivity over the past 300 million years

    PubMed Central

    Beerling, D. J.

    1999-01-01

    Changes in marine primary production over geological time have influenced a network of global biogeochemical cycles with corresponding feedbacks on climate. However, these changes continue to remain largely unquantified because of uncertainties in calculating global estimates from sedimentary palaeoproductivity indicators. I therefore describe a new approach to the problem using a mass balance analysis of the stable isotopes (18O/16O) of oxygen with modelled O2 fluxes and isotopic exchanges by terrestrial vegetation for 300, 150, 100 and 50 million years before present, and the treatment of the Earth as a closed system, with respect to the cycling of O2. Calculated in this way, oceanic net primary productivity was low in the Carboniferous but high (up to four times that of modern oceans) during the Late Jurassic, mid-Cretaceous and early Eocene greenhouse eras with a greater requirement for key nutrients. Such a requirement would be compatible with accelerated rates of continental weathering under the greenhouse conditions of the Mesozoic and early Tertiary. These results indicate possible changes in the strength of a key component of the oceanic carbon (organic and carbonate) pump in the geological past, with a corresponding feedback on atmospheric CO2 and climate, and provide an improved framework for understanding the role of ocean biota in the evolution of the global biogeochemical cycles of C, N and P.

  8. 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.

  9. 70 million years of coastal upwelling in California; source rocks and paleoceanography

    SciTech Connect

    Fonseca, C.

    1996-12-31

    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.

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

    PubMed

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

    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.

  11. Multiple Reversals of Bill Length over 1.7 Million Years in a Hawaiian Bird Lineage.

    PubMed

    Freed, Leonard A; Medeiros, Matthew C I; Cann, Rebecca L

    2016-03-01

    Evolutionary change has been documented over geological time, but reversals in morphology, from an ancestral state to a derived state and back again, tend to be rare. Multiple reversals along the same lineage are even rarer. We use the chronology of the Hawaiian Islands and an avian example, the Hawaiian honeycreeper 'amakihi (Hemignathus spp.) lineage, which originated on the oldest main island of Kaua'i 1.7 million years ago, to examine the process of sequential reversals in bill length. We document three single and two multiple reversals of bill length on six main islands from oldest to youngest, consistent with the phylogeny of the lineage. Longer bills occur on islands with endemic species, including phylogenetically relevant outgroups, that may compete with or dominate the 'amakihi. On islands without those species, the 'amakihi had shorter bills of similar length. Both types of reversals in morphology in this lineage integrate microevolutionary processes with macroevolution in the adaptive radiation of Hawaiian honeycreepers. PMID:26913948

  12. 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.

  13. Ancestry Influences the Fate of Duplicated Genes Millions of Years After Polyploidization of Clawed Frogs (Xenopus)

    PubMed Central

    Evans, Ben J.

    2007-01-01

    Allopolyploid species form through the fusion of two differentiated genomes and, in the earliest stages of their evolution, essentially all genes in the nucleus are duplicated. Because unique mutations occur in each ancestor prior to allopolyploidization, duplicate genes in these species potentially are not interchangeable, and this could influence their genetic fates. This study explores evolution and expression of a simple duplicated complex—a heterodimer between RAG1 and RAG2 proteins in clawed frogs (Xenopus). Results demonstrate that copies of RAG1 degenerated in different polyploid species in a phylogenetically biased fashion, predominately in only one lineage of closely related paralogs. Surprisingly, as a result of an early deletion of one RAG2 paralog, it appears that in many species RAG1/RAG2 heterodimers are composed of proteins that were encoded by unlinked paralogs. If the tetraploid ancestor of extant species of Xenopus arose through allopolyploidization and if recombination between paralogs was rare, then the genes that encode functional RAG1 and RAG2 proteins in many polyploid species were each ultimately inherited from different diploid progenitors. These observations are consistent with the notion that ancestry can influence the fate of duplicate genes millions of years after duplication, and they uncover a dimension of natural selection in allopolyploid genomes that is distinct from other genetic phenomena associated with polyploidization or segmental duplication. PMID:17435227

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

    PubMed

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

    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. PMID:27092007

  15. 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. PMID:26729865

  16. Virtual dissection and lifestyle of a 165 -million-year-old female polychelidan lobster.

    PubMed

    Jauvion, Clément; Audo, Denis; Charbonnier, Sylvain; Vannier, Jean

    2016-03-01

    Polychelidan lobsters are fascinating crustaceans that were known as fossils before being discovered in the deep-sea. They differ from other crustaceans by having four to five pairs of claws. Although recent palaeontological studies have clarified the systematics and phylogeny of the group, the biology of extant polychelidans and--first of all--their anatomy are poorly documented. Numerous aspects of the evolutionary history of the group remain obscure, in particular, how and when polychelidans colonized the deep-sea and became restricted to it. Surprisingly, the biology of extant polychelidans and the anatomy of all species, fossil and recent, are poorly documented. Here, X-ray microtomography (XTM), applied to an exceptionally well-preserved specimen from the La Voulte Lagerstätte, reveals for the first time vital aspects of the external and internal morphology of Voulteryon parvulus (Eryonidae), a 165-million-year-old polychelidan: 1) its mouthparts (maxillae and maxillipeds), 2) its digestive tract and 3) its reproductive organs. Comparisons with dissected specimens clearly identify this specimen as a female with mature ovaries. This set of new information offers new insights into the feeding and reproductive habits of Mesozoic polychelidans. Contrasting with other Jurassic polychelidans that lived in shallow-water environments, V. parvulus spawned in, and probably inhabited, relatively deep-water environments, as do the survivors of the group. PMID:26577513

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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. PMID:27324847

  2. Conserved metallomics in two insect families evolving separately for a hundred million years.

    PubMed

    Rempoulakis, Polychronis; Afshar, Negar; Osorio, Beatriz; Barajas-Aceves, Martha; Szular, Joanna; Ahmad, Sohel; Dammalage, Thilakasiri; Tomas, Ulysses Sto; Nemny-Lavy, Esther; Salomon, Mor; Vreysen, Marc J B; Nestel, David; Missirlis, Fanis

    2014-12-01

    Μetal cofactors are required for enzymatic catalysis and structural stability of many proteins. Physiological metal requirements underpin the evolution of cellular and systemic regulatory mechanisms for metal uptake, storage and excretion. Considering the role of metal biology in animal evolution, this paper asks whether metal content is conserved between different fruit flies. A similar metal homeostasis was previously observed in Drosophilidae flies cultivated on the same larval medium. Each species accumulated in the order of 200 µg iron and zinc and approximately ten-fold less manganese and copper per gram dry weight of the adult insect. In this paper, data on the metal content in fourteen species of Tephritidae, which are major agricultural pests worldwide, are presented. These fruit flies can be polyphagous (e.g., Ceratitis capitata) or strictly monophagous (e.g., Bactrocera oleae) or oligophagous (e.g., Anastrepha grandis) and were maintained in the laboratory on five distinct diets based on olive oil, carrot, wheat bran, zucchini and molasses, respectively. The data indicate that overall metal content and distribution between the Tephritidae and Drosophilidae species was similar. Reduced metal concentration was observed in B. oleae. Feeding the polyphagous C. capitata with the diet of B. oleae resulted in a significant quantitative reduction of all metals. Thus, dietary components affect metal content in some Tephritidae. Nevertheless, although the evidence suggests some fruit fly species evolved preferences in the use or storage of particular metals, no metal concentration varied in order of magnitude between these two families of Diptera that evolved independently for over 100 million years. PMID:25298233

  3. 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.

  4. 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

  5. Curiously modern DNA for a "250 million-year-old" bacterium.

    PubMed

    Nickle, David C; Learn, Gerald H; Rain, Matthew W; Mullins, James I; Mittler, John E

    2002-01-01

    Studies of ancient DNA have attracted considerable attention in scientific journals and the popular press. Several of the more extreme claims for ancient DNA have been questioned on biochemical grounds (i.e., DNA surviving longer than expected) and evolutionary grounds (i.e., nucleotide substitution patterns not matching theoretical expectations for ancient DNA). A recent letter to Nature from Vreeland et al. (2000), however, tops all others with respect to age and condition of the specimen. These researchers extracted and cultured a bacterium from an inclusion body from what they claim is a 250 million-year (Myr)-old salt crystal. If substantiated, this observation could fundamentally alter views about bacterial physiology, ecology and evolution. Here we report on molecular evolutionary analyses of the 16S rDNA from this specimen. We find that 2-9-3 differs from a modern halophile, Salibacillus marismortui, by just 3 unambiguous bp in 16S rDNA, versus the approximately 59 bp that would be expected if these bacteria evolved at the same rate as other bacteria. We show, using a Poisson distribution, that unless it can be shown that S. marismortui evolves 5 to 10 times more slowly than other bacteria for which 16S rDNA substitution rates have been established, Vreeland et al.'s claim would be rejected at the 0.05 level. Also, a molecular clock test and a relative rates test fail to substantiate Vreeland et al.'s claim that strain 2-9-3 is a 250-Myr-old bacterium. The report of Vreeland et al. thus falls into a long series of suspect ancient DNA studies.

  6. 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. PMID:26324909

  7. 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

  8. 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

  9. 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.

  10. Conserved metallomics in two insect families evolving separately for a hundred million years.

    PubMed

    Rempoulakis, Polychronis; Afshar, Negar; Osorio, Beatriz; Barajas-Aceves, Martha; Szular, Joanna; Ahmad, Sohel; Dammalage, Thilakasiri; Tomas, Ulysses Sto; Nemny-Lavy, Esther; Salomon, Mor; Vreysen, Marc J B; Nestel, David; Missirlis, Fanis

    2014-12-01

    Μetal cofactors are required for enzymatic catalysis and structural stability of many proteins. Physiological metal requirements underpin the evolution of cellular and systemic regulatory mechanisms for metal uptake, storage and excretion. Considering the role of metal biology in animal evolution, this paper asks whether metal content is conserved between different fruit flies. A similar metal homeostasis was previously observed in Drosophilidae flies cultivated on the same larval medium. Each species accumulated in the order of 200 µg iron and zinc and approximately ten-fold less manganese and copper per gram dry weight of the adult insect. In this paper, data on the metal content in fourteen species of Tephritidae, which are major agricultural pests worldwide, are presented. These fruit flies can be polyphagous (e.g., Ceratitis capitata) or strictly monophagous (e.g., Bactrocera oleae) or oligophagous (e.g., Anastrepha grandis) and were maintained in the laboratory on five distinct diets based on olive oil, carrot, wheat bran, zucchini and molasses, respectively. The data indicate that overall metal content and distribution between the Tephritidae and Drosophilidae species was similar. Reduced metal concentration was observed in B. oleae. Feeding the polyphagous C. capitata with the diet of B. oleae resulted in a significant quantitative reduction of all metals. Thus, dietary components affect metal content in some Tephritidae. Nevertheless, although the evidence suggests some fruit fly species evolved preferences in the use or storage of particular metals, no metal concentration varied in order of magnitude between these two families of Diptera that evolved independently for over 100 million years.

  11. Adaptive evolution of voltage-gated sodium channels: The first 800 million years

    PubMed Central

    Zakon, Harold H.

    2012-01-01

    Voltage-gated Na+-permeable (Nav) channels form the basis for electrical excitability in animals. Nav channels evolved from Ca2+ channels and were present in the common ancestor of choanoflagellates and animals, although this channel was likely permeable to both Na+ and Ca2+. Thus, like many other neuronal channels and receptors, Nav channels predated neurons. Invertebrates possess two Nav channels (Nav1 and Nav2), whereas vertebrate Nav channels are of the Nav1 family. Approximately 500 Mya in early chordates Nav channels evolved a motif that allowed them to cluster at axon initial segments, 50 million years later with the evolution of myelin, Nav channels “capitalized” on this property and clustered at nodes of Ranvier. The enhancement of conduction velocity along with the evolution of jaws likely made early gnathostomes fierce predators and the dominant vertebrates in the ocean. Later in vertebrate evolution, the Nav channel gene family expanded in parallel in tetrapods and teleosts (∼9 to 10 genes in amniotes, 8 in teleosts). This expansion occurred during or after the late Devonian extinction, when teleosts and tetrapods each diversified in their respective habitats, and coincided with an increase in the number of telencephalic nuclei in both groups. The expansion of Nav channels may have allowed for more sophisticated neural computation and tailoring of Nav channel kinetics with potassium channel kinetics to enhance energy savings. Nav channels show adaptive sequence evolution for increasing diversity in communication signals (electric fish), in protection against lethal Nav channel toxins (snakes, newts, pufferfish, insects), and in specialized habitats (naked mole rats). PMID:22723361

  12. 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

  13. 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. PMID:21149686

  14. 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.

  15. Identifying concerted evolution and gene conversion in mammalian gene pairs lasting over 100 million years

    PubMed Central

    Carson, Andrew R; Scherer, Stephen W

    2009-01-01

    Background Concerted evolution occurs in multigene families and is characterized by stretches of homogeneity and higher sequence similarity between paralogues than between orthologues. Here we identify human gene pairs that have undergone concerted evolution, caused by ongoing gene conversion, since at least the human-mouse divergence. Our strategy involved the identification of duplicated genes with greater similarity within a species than between species. These genes were required to be present in multiple mammalian genomes, suggesting duplication early in mammalian divergence. To eliminate genes that have been conserved due to strong purifying selection, our analysis also required at least one intron to have retained high sequence similarity between paralogues. Results We identified three human gene pairs undergoing concerted evolution (BMP8A/B, DDX19A/B, and TUBG1/2). Phylogenetic investigations reveal that in each case the duplication appears to have occurred prior to eutherian mammalian radiation, with exactly two paralogues present in all examined species. This indicates that all three gene duplication events were established over 100 million years ago. Conclusion The extended duration of concerted evolution in multiple distant lineages suggests that there has been prolonged homogenization of specific segments within these gene pairs. Although we speculate that selection for homogenization could have been utilized in order to maintain crucial homo- or hetero- binding domains, it remains unclear why gene conversion has persisted for such extended periods of time. Through these analyses, our results demonstrate additional examples of a process that plays a definite, although unspecified, role in molecular evolution. PMID:19583854

  16. Early problematic eating behaviours are associated with lower fruit and vegetable intake and less dietary variety at 4-5 years of age. A prospective analysis of three European birth cohorts.

    PubMed

    Oliveira, A; Jones, L; de Lauzon-Guillain, B; Emmett, P; Moreira, P; Charles, M A; Lopes, C

    2015-09-14

    Problematic eating behaviours during early childhood could be mediators of poor dietary habits. This study aims to prospectively relate early eating behaviours with fruit and vegetable (F&V) intake and a healthy diet variety score of children aged between 4 and 5 years. Eating behaviours were assessed in three European birth cohorts (Generation XXI from Portugal, ALSPAC from the UK and EDEN from France) at 4-6, 12-15, 24 and 48-54 months of age, based on the child's feeding difficulties, mother's perception of child's poor eating (eating small quantities at each meal, not eating enough or needing to be stimulated to eat), food refusal and difficulties in the establishment of daily food routines. Daily servings of F&V (>1 v. ≤1 serving/d, except in Generation XXI: >3 v. ≤3) and the Healthy Plate Variety Score (categorised by the median score of each sample) were calculated using FFQ. Associations were tested by logistic regressions adjusted for maternal age, education, smoking during pregnancy, any breast-feeding and the child's z-score BMI at 4-5 years of age. Children with more feeding difficulties, poor eating, food refusal/neophobia and difficulties in establishing a daily routine at 12-15, 24 and 48-54 months of age had in general lower F&V intake at 4-5 years of age. The association with vegetables was slightly stronger than with fruits. These early feeding problems were also inversely associated with the variety score at 4-5 years of age, particularly when eating behaviours were reported after 12-15 months of age. A better understanding of these early feeding difficulties may help define strategies to increase the dietary quality in children. PMID:26195187

  17. Early problematic eating behaviours are associated with lower fruit and vegetable intake and less dietary variety at 4-5 years of age. A prospective analysis of three European birth cohorts.

    PubMed

    Oliveira, A; Jones, L; de Lauzon-Guillain, B; Emmett, P; Moreira, P; Charles, M A; Lopes, C

    2015-09-14

    Problematic eating behaviours during early childhood could be mediators of poor dietary habits. This study aims to prospectively relate early eating behaviours with fruit and vegetable (F&V) intake and a healthy diet variety score of children aged between 4 and 5 years. Eating behaviours were assessed in three European birth cohorts (Generation XXI from Portugal, ALSPAC from the UK and EDEN from France) at 4-6, 12-15, 24 and 48-54 months of age, based on the child's feeding difficulties, mother's perception of child's poor eating (eating small quantities at each meal, not eating enough or needing to be stimulated to eat), food refusal and difficulties in the establishment of daily food routines. Daily servings of F&V (>1 v. ≤1 serving/d, except in Generation XXI: >3 v. ≤3) and the Healthy Plate Variety Score (categorised by the median score of each sample) were calculated using FFQ. Associations were tested by logistic regressions adjusted for maternal age, education, smoking during pregnancy, any breast-feeding and the child's z-score BMI at 4-5 years of age. Children with more feeding difficulties, poor eating, food refusal/neophobia and difficulties in establishing a daily routine at 12-15, 24 and 48-54 months of age had in general lower F&V intake at 4-5 years of age. The association with vegetables was slightly stronger than with fruits. These early feeding problems were also inversely associated with the variety score at 4-5 years of age, particularly when eating behaviours were reported after 12-15 months of age. A better understanding of these early feeding difficulties may help define strategies to increase the dietary quality in children.

  18. 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…

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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.

  4. Global tectonics since the breakup of Pangea 180 million years ago: evolution maps and lithospheric budget

    NASA Astrophysics Data System (ADS)

    Weijermars, Ruud

    Pangea, the Earth's youngest single supercontinent, broke up 180 million years ago. Tectonic plates were subsequently formed by dispersal of the continental fragments and accretion of new oceanic lithosphere. The configurations of all the major lithospheric plates at 0, 20, 65, 95, 140, 180 Ma BP are reconstructed on six globes of the Earth, each with a radius of 10 cm. It appears that plate boundaries maintain a remarkably close fit on model globes of constant radii if the reconstructions include the recovery of subducted spreading patterns. This is illustrated with maps in equatorial orthographic, oblique orthographic and transverse Hammer-Aitoff projections. The snug fit of the tectonic plates at every tested time since the breakup of Pangea 180 Ma BP is consistent with the theory of plate tectonics on a non-expanding Earth and contradicts rapidly expanding Earth models. The areas of oceanic lithosphere produced and consumed during the past 180 Ma BP are estimated from surface measurements of the globes reconstructed on the basis of particular assumptions. These measurements suggest a consistent increase in the production rate of oceanic lithosphere during the past 140 Ma. It was decided to revise the assumptions and see if alternative reconstructions of the ancient spreading patterns on the floors of the Tethys and Eo-Pacific oceans could avoid implying an increase of lithospheric production rates with time. This appeared to be possible. The revised maps suggest that ophiolites older than 180 Ma BP may have been obducted in Cenozoic collision zones of the Himalayas, Andes, Rockies, and the western part of the Banda Arc (Timor, New Guinea). Estimates of the ocean floor production and consumption budget appear to be quite similar for both map series, and only the possible ranges are summarized here, time averaged for the past 180 Ma. World-wide production and consumption of oceanic lithosphere appears to have varied between 2.6 and 3.5 km 2 a -1 at most. The mean

  5. 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

  6. 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.

  7. 2,4,5-Trichlorophenol

    Integrated Risk Information System (IRIS)

    2,4,5 - Trichlorophenol ; CASRN 95 - 95 - 4 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

  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

    2015-01-01

    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

  9. 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

  10. Conservation of Plastid Sequences in the Plant Nuclear Genome for Millions of Years Facilitates Endosymbiotic Evolution1[W][OA

    PubMed Central

    Rousseau-Gueutin, Mathieu; Ayliffe, Michael A.; Timmis, Jeremy N.

    2011-01-01

    The nuclear genome of eukaryotes contains large amounts of cytoplasmic organelle DNA (nuclear integrants of organelle DNA [norgs]). The recent sequencing of many mitochondrial and chloroplast genomes has enabled investigation of the potential role of norgs in endosymbiotic evolution. In this article, we describe a new polymerase chain reaction-based method that allows the identification and evolutionary study of recent and older norgs in a range of eukaryotes. We tested this method in the genus Nicotiana and obtained sequences from seven nuclear integrants of plastid DNA (nupts) totaling 25 kb in length. These nupts were estimated to have been transferred 0.033 to 5.81 million years ago. The spectrum of mutations present in the potential protein-coding sequences compared with the noncoding sequences of each nupt revealed that nupts evolve in a nuclear-specific manner and are under neutral evolution. Indels were more frequent in noncoding regions than in potential coding sequences of former chloroplastic DNA, most probably due to the presence of a higher number of homopolymeric sequences. Unexpectedly, some potential protein-coding sequences within the nupts still contained intact open reading frames for up to 5.81 million years. These results suggest that chloroplast genes transferred to the nucleus have in some cases several millions of years to acquire nuclear regulatory elements and become functional. The different factors influencing this time frame and the potential role of nupts in endosymbiotic gene transfer are discussed. PMID:22034627

  11. Remarkable morphological stasis in an extant vertebrate despite tens of millions of years of divergence.

    PubMed

    Lavoué, Sébastien; Miya, Masaki; Arnegard, Matthew E; McIntyre, Peter B; Mamonekene, Victor; Nishida, Mutsumi

    2011-04-01

    The relationship between genotypic and phenotypic divergence over evolutionary time varies widely, and cases of rapid phenotypic differentiation despite genetic similarity have attracted much attention. Here, we report an extreme case of the reverse pattern--morphological stasis in a tropical fish despite massive genetic divergence. We studied the enigmatic African freshwater butterfly fish (Pantodon buchholzi), whose distinctive morphology earns it recognition as a monotypic family. We sequenced the mitochondrial genome of Pantodon from the Congo basin and nine other osteoglossomorph taxa for comparison with previous mitogenomic profiles of Pantodon from the Niger basin and other related taxa. Pantodon populations form a monophyletic group, yet their mitochondrial coding sequences differ by 15.2 per cent between the Niger and Congo basins. The mitogenomic divergence time between these populations is estimated to be greater than 50 Myr, and deep genetic divergence was confirmed by nuclear sequence data. Among six sister-group comparisons of osteoglossomorphs, Pantodon exhibits the slowest rate of morphological divergence despite a level of genetic differentiation comparable to both species-rich (e.g. Mormyridae) and species-poor (e.g. Osteoglossidae) families. Morphological stasis in these two allopatric lineages of Pantodon offers a living vertebrate model for investigating phenotypic stability over millions of generations in the face of profound fluctuations in environmental conditions.

  12. 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.

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

    PubMed

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

    1981-06-26

    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 x 10(6) years with an initial (143)Nd/(144)Nd ratio of 0.50798 +/- 0.00007. This age contrasts with the rubidium-strontium age of 3200 x 10(6) 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 x l0(6) years ago.

  14. 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. PMID:16195457

  15. 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.

  16. 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

  17. Exotic minerals in 3,500 million year old rocks: Evidence for large meteorite impacts

    NASA Technical Reports Server (NTRS)

    Byerly, G. R.; Lowe, D. R.; Asaro, F.

    1988-01-01

    A relatively small area of mountainous terrain in southern Africa provides scientists from all over the world a look at what the surface of the earth was like three and a half billion years ago. The Barberton Mountains lie astride the borders of the Republic of South Africa, Mozambique, and the Kingdom of Swaziland. The discovery of several widely distributed deposits that were likely formed by major terrestrial impacts of large extraterrestrial bodies during this early period of earth's history is reported. The Barberton impact deposits are being studied by electron microscopy. The impact deposits were examined for minerals that show the effects of shock metamorphism or compositions unusual in terrestrial rocks.

  18. 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. PMID:27324846

  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. More than half a million older Californians fell repeatedly in the past year.

    PubMed

    Wallace, Steven P

    2014-11-01

    Falls are the leading injury-related cause of death and of medical care use among Californians ages 65 and over. In 2012, there were 1,819 deaths due to falls among older Californians. More than 72,000 hospitalizations were caused by fall injuries among older adults during that year, along with more than 185,000 emergency department (ED) visits. The medical costs alone of falls in the state have been estimated to be over $2 billion annually. Those who have fallen more than once are at the highest risk of injury and further falls. Data from the 2011-2012 California Health Interview Survey show that 12.6 percent of older Californians, or 556,000 individuals, had fallen more than once during the past year. Very few of those experiencing multiple falls discussed how to reduce their risk with a health professional. This policy brief details the characteristics of older Californians who have repeated falls, their health care use, and the actions they can take to reduce the risk of future falls. It also provides policy suggestions for reducing the risk of falls among older Californians and decreasing the costs to the medical care system.

  3. Is there 1 million-year old ice near Dome C, Antarctica?

    NASA Astrophysics Data System (ADS)

    Parrenin, Frédéric; Blankenship, Donald D.; Cavitte, Marie G. P.; Chappellaz, Jérôme; Fischer, Hubertus; Gagliardini, Olivier; Gillet-Chaulet, Fabien; Masson-Delmotte, Valérie; Passalacqua, Olivier; Ritz, Catherine; Siegert, Martin J.; Young, Duncan

    2015-04-01

    Ice sheets provide exceptional archives of past changes in polar climate, regional environment and global atmospheric composition. The oldest deep ice drilled in Antarctica has been retrieved at EPICA Dome C (Antarctica), reaching 800,000 years. Retrieving an older paleoclimatic record from Antarctica is one of the biggest challenges of the ice core community. Here, we use a combination of internal layers identified with airborne radar and ice-flow modeling to estimate the age of basal ice along two transects across the Dome C summit. Based on the age of the bottom ic eat EDC, we find a geothermal heat flux of 66.8 mW/m2. Assuming the same geothermal heat flux all along both transects, we identify a region located only ~40 km from the dome on a bedrock relilef where the estimated basal melting is small or inexistant. As a result, basal age is estimated to be >1,500,000 years. However, this oldest ice hot spot disappears if the geothermal heat flux is only 5 mW/m2 higher than at EDC. Our work also demonstrates the utility of combining radar layering with ice flow modelling to accurately represent the true nature of ice flow in the center of large ice sheets.

  4. Thirty Years, One Million Spectra: Public Access to the SAO Spectral Archives

    NASA Astrophysics Data System (ADS)

    Mink, J.; Moran, S.

    2015-09-01

    Over the last 30 years, the SAO Telescope Data Center has reduced and archived over 1,000,000 spectra, consisting of 287,000 spectra from five high dispersion Echelle spectrographs and 717,000 spectra from four low dispersion spectrographs, across three telescopes. 151,000 spectra from six instruments are currently online and publicly available, covering many interesting objects in the northern sky, including most of the galaxies in the Updated Zwicky Catalog which are reachable through NED or Simbad. A majority of the high dispersion spectra will soon be made public, as will more data from the MMT multi-fiber spectrographs. Many objects in the archive have multiple spectra over time, which make them a valuable resource for archival time-domain studies. We are now developing a system to make all of the public spectra more easily searchable and viewable through the Virtual Observatory.

  5. 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

  6. Sound strategies: the 65-million-year-old battle between bats and insects.

    PubMed

    Conner, William E; Corcoran, Aaron J

    2012-01-01

    The intimate details regarding the coevolution of bats and moths have been elucidated over the past 50 years. The bat-moth story began with the evolution of bat sonar, an exquisite ultrasonic system for tracking prey through the night sky. Moths countered with ears tuned to the high frequencies of bat echolocation and with evasive action through directed turns, loops, spirals, drops, and power dives. Some bat species responded by moving the frequency and intensity of their echolocation cries away from the peak sensitivity of moth ears, and the arms race was on. Tiger moths countered by producing anti-bat sounds. Do the sounds advertise moth toxicity, similar to the bright coloration of butterflies; do they startle the bat, giving the moth a momentary advantage in their aerobatic battle; or do they jam the sonar of the bat? The answer is yes. They do all and more in different situations and in different species. Any insect that flies at night must deal with bat predation. Beetles, mantids, true crickets, mole crickets, katydids, green lacewings, and locusts have anti-bat strategies, and we have just scratched the surface. In an exciting new twist, researchers are taking the technologies developed in the laboratory back into the field, where they are poised to appreciate the full richness of this remarkable predator-prey interaction. PMID:21888517

  7. Sound strategies: the 65-million-year-old battle between bats and insects.

    PubMed

    Conner, William E; Corcoran, Aaron J

    2012-01-01

    The intimate details regarding the coevolution of bats and moths have been elucidated over the past 50 years. The bat-moth story began with the evolution of bat sonar, an exquisite ultrasonic system for tracking prey through the night sky. Moths countered with ears tuned to the high frequencies of bat echolocation and with evasive action through directed turns, loops, spirals, drops, and power dives. Some bat species responded by moving the frequency and intensity of their echolocation cries away from the peak sensitivity of moth ears, and the arms race was on. Tiger moths countered by producing anti-bat sounds. Do the sounds advertise moth toxicity, similar to the bright coloration of butterflies; do they startle the bat, giving the moth a momentary advantage in their aerobatic battle; or do they jam the sonar of the bat? The answer is yes. They do all and more in different situations and in different species. Any insect that flies at night must deal with bat predation. Beetles, mantids, true crickets, mole crickets, katydids, green lacewings, and locusts have anti-bat strategies, and we have just scratched the surface. In an exciting new twist, researchers are taking the technologies developed in the laboratory back into the field, where they are poised to appreciate the full richness of this remarkable predator-prey interaction.

  8. First identification of natural products from the African medicinal plant Zamioculcas zamiifolia - A drought resistant survivor through millions of years.

    PubMed

    Le Moullec, Angharad; Juvik, Ole Johan; Fossen, Torgils

    2015-10-01

    Zamioculcas zamiifolia, an unusually drought resistant medicinal plant native to tropical east Africa and subtropical southeast Africa, including the countries Kenya, Malawi, Mozambique, South-Africa, Tanzania and Zimbabwe, is described as a living fossil which may have evolved as early as 42 million years ago. It belongs to the notoriously toxic family Araceae giving it, through association, a reputation for being toxic; despite little or no systematic evidence exists to support this claim. As an ancient plant it has sustained substantial climate changes and attacks from millions of generations of pathogenic microorganisms, which encouraged search for novel natural products from this source. Seven natural products have been characterized from leaves and petioles of Z. zamiifolia, including the novel main compound of the leaves, apigenin 6-C-(6″-(3-hydroxy-3-methyl-glutaroyl)-ß-glucopyranoside). The structure determinations were based on extensive use of 2D NMR spectroscopic techniques and high-resolution mass spectrometry. Initial toxicological experiment on extracts from Z. zamiifolia using brine shrimp lethality assay did not indicate lethality to the shrimps providing disproving evidence for the assumption of Z. zamiifolia's toxic character.

  9. First identification of natural products from the African medicinal plant Zamioculcas zamiifolia - A drought resistant survivor through millions of years.

    PubMed

    Le Moullec, Angharad; Juvik, Ole Johan; Fossen, Torgils

    2015-10-01

    Zamioculcas zamiifolia, an unusually drought resistant medicinal plant native to tropical east Africa and subtropical southeast Africa, including the countries Kenya, Malawi, Mozambique, South-Africa, Tanzania and Zimbabwe, is described as a living fossil which may have evolved as early as 42 million years ago. It belongs to the notoriously toxic family Araceae giving it, through association, a reputation for being toxic; despite little or no systematic evidence exists to support this claim. As an ancient plant it has sustained substantial climate changes and attacks from millions of generations of pathogenic microorganisms, which encouraged search for novel natural products from this source. Seven natural products have been characterized from leaves and petioles of Z. zamiifolia, including the novel main compound of the leaves, apigenin 6-C-(6″-(3-hydroxy-3-methyl-glutaroyl)-ß-glucopyranoside). The structure determinations were based on extensive use of 2D NMR spectroscopic techniques and high-resolution mass spectrometry. Initial toxicological experiment on extracts from Z. zamiifolia using brine shrimp lethality assay did not indicate lethality to the shrimps providing disproving evidence for the assumption of Z. zamiifolia's toxic character. PMID:26385196

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. A major meteorite impact on the Earth 65 million years ago: evidence from the cretaceous-tertiary boundary clay.

    PubMed

    Ganapathy, R

    1980-08-22

    Evidence for a major meteorite impact on the earth 65 million years ago is shown by the presence of meteoritic debris in the "fish clay" from Denmark representing the Cretaceous-Tertiary boundary. Noble metals (iridium, osmium, gold, platinum, rhenium, ruthenium, palladium, nickel, and cobalt), which are sensitive indicators of meteorites and are normally depleted on the terrestrial surface by factors of 10(4) to 10(2) relative to cosmic abundances, are enriched in this boundary clay by factors of 5 to 100 over the expected abundances. With the exception of rhenium, all the enriched noble metals in the clay are present in cosmic proportions, indicating that the impacting celestial body had not undergone gross chemical differentiation. The major extinction of life on the earth at the end of the Cretaceous Period may be related to the meteorite impact.

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

    PubMed

    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

  16. 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

  17. 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.

  18. 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. PMID:26565453

  19. Two-level systems and boson peak remain stable in 110-million-year-old amber glass.

    PubMed

    Pérez-Castañeda, Tomás; Jiménez-Riobóo, Rafael J; Ramos, Miguel A

    2014-04-25

    The two most prominent and ubiquitous features of glasses at low temperatures, namely the presence of tunneling two-level systems and the so-called boson peak in the reduced vibrational density of states, are shown to persist essentially unchanged in highly stabilized glasses, contrary to what was usually envisaged. Specifically, we have measured the specific heat of 110 million-year-old amber samples from El Soplao (Spain), both at very low temperatures and around the glass transition Tg. In particular, the amount of two-level systems, assessed at the lowest temperatures, was surprisingly found to be exactly the same for the pristine hyperaged amber as for the, subsequently, partially and fully rejuvenated samples.

  20. Two-level systems and boson peak remain stable in 110-million-year-old amber glass.

    PubMed

    Pérez-Castañeda, Tomás; Jiménez-Riobóo, Rafael J; Ramos, Miguel A

    2014-04-25

    The two most prominent and ubiquitous features of glasses at low temperatures, namely the presence of tunneling two-level systems and the so-called boson peak in the reduced vibrational density of states, are shown to persist essentially unchanged in highly stabilized glasses, contrary to what was usually envisaged. Specifically, we have measured the specific heat of 110 million-year-old amber samples from El Soplao (Spain), both at very low temperatures and around the glass transition Tg. In particular, the amount of two-level systems, assessed at the lowest temperatures, was surprisingly found to be exactly the same for the pristine hyperaged amber as for the, subsequently, partially and fully rejuvenated samples. PMID:24815658

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

    PubMed

    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

  2. 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).

  3. 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.

  4. 19 CFR 4.5 - Government vessels.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Government vessels. 4.5 Section 4.5 Customs Duties... VESSELS IN FOREIGN AND DOMESTIC TRADES Arrival and Entry of Vessels § 4.5 Government vessels. (a) No... that is the property of, the U.S. Department of Defense (DoD) will be treated as a Government...

  5. 19 CFR 4.5 - Government vessels.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Government vessels. 4.5 Section 4.5 Customs Duties... VESSELS IN FOREIGN AND DOMESTIC TRADES Arrival and Entry of Vessels § 4.5 Government vessels. (a) No... that is the property of, the U.S. Department of Defense (DoD) will be treated as a Government...

  6. 19 CFR 4.5 - Government vessels.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Government vessels. 4.5 Section 4.5 Customs Duties... VESSELS IN FOREIGN AND DOMESTIC TRADES Arrival and Entry of Vessels § 4.5 Government vessels. (a) No... that is the property of, the U.S. Department of Defense (DoD) will be treated as a Government...

  7. 19 CFR 4.5 - Government vessels.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Government vessels. 4.5 Section 4.5 Customs Duties... VESSELS IN FOREIGN AND DOMESTIC TRADES Arrival and Entry of Vessels § 4.5 Government vessels. (a) No... that is the property of, the U.S. Department of Defense (DoD) will be treated as a Government...

  8. 19 CFR 4.5 - Government vessels.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Government vessels. 4.5 Section 4.5 Customs Duties... VESSELS IN FOREIGN AND DOMESTIC TRADES Arrival and Entry of Vessels § 4.5 Government vessels. (a) No... that is the property of, the U.S. Department of Defense (DoD) will be treated as a Government...

  9. High-resolution reconstruction of Arctic paleoclimate derived from 53 million year old kimberlite-hosted Metasequoia wood

    NASA Astrophysics Data System (ADS)

    Walker, J. J.; Halfar, J.; Schulze, D.; Gedalof, Z.; Moore, G. W. K.

    2009-04-01

    The recovery of exceptionally well preserved Eocene wood from kimberlite pipes in the Lac de Gras region of the Northwest Territories, Canada, has allowed for the characterization of the local temperature and hydrologic patterns on an annual scale for this arctic ecosystem (present day latitude: 64 deg N). Wood fragments of ancient Metasequoia sp. trees mixed into the crater facies during kimberlite emplacement were recovered from the Ekati and Diavik diamond mines. Wood recovered from the Ekati "Panda" pipe, which has been dated using Rb-Sr age determination at 53.3 +/- 0.6 million years, is unique in that it exhibits extremely low vitrinite reflectance values, comparable to that of modern near-surface peats. The implication is that the wood has undergone minimal thermal or compressional alteration, thus preserving the geochemical signatures originally formed during growth. Ring width measurements representing over 100 years of climate data show congruence between multiple samples, thus enabling the development of a floating master chronology. Patterns contained in this chronology are of particular interest as the early Eocene was characterized by a period of unusual warming that has been compared to modern day climate change. Wood cellulose does not exchange atoms with its surroundings after formation, making it an ideal candidate for stable isotope analysis once it has been separated from associated whole-wood components. A robotic micromilling device was used to collect whole wood samples of latewood from annual tree rings. The α-cellulose in the samples will be isolated and analyzed for δ13C and δ18O, generating a 34-year floating chronology that can be used to reconstruct decadal scale temperature and humidity patterns. Successful application of this technique suggests that a longer Eocene chronology, using additional wood samples recovered from the Panda pipe as well as samples from neighbouring pipes in the Lac de Gras region, can be developed.

  10. A 2.3 Million Year Lacustrine Record of Orbital Forcing from the Devonian of Northern Scotland

    NASA Astrophysics Data System (ADS)

    Andrews, Steven; Cornwell, David; Trewin, Nigel; Hartley, Adrian; Archer, Stuart

    2015-04-01

    Detailed sedimentological examination of well exposed onshore sections through the continental Middle Devonian succession of northern Scotland have been augmented with offshore well data to allow the construction of a continuous 2.3 million year record of orbital forcing. The Middle Devonian of Northern Scotland comprises a succession of cyclic lacustrine deposits. The onshore exposures of this succession, although well exposed, are disrupted by faulting. Hand held gamma logging of onshore exposures has allowed direct ties to be made to adjacent offshore well data which provides a continuous record through the lacustrine succession. Further onshore sections, shown to be representative of those identified in the offshore data, help define the orbital periodicities influencing sedimentation and furthermore, provide insights in to the response of the lacustrine system through time. Periodicities reflecting the Precessional (19 886 years) and Eccentricity (100 000 years) cycles are shown to be dominant by the direct measurement and extrapolation of depositional rates in well exposed sections as well as the analysis of ratios between primary and, modulating, secondary cycles. The demonstration of a robust link between gamma log response and lithology in the onshore cycles allows the offshore data to be to be interrogated for evidence of the long term climatic forcing of sedimentation. Fourier analysis has confirmed the presence of regular cycles throughout the succession which vary in thickness similarly to the onshore records. Variations in cycle thickness and symmetry are related to a trend from an underfilled to a balanced fill lacustrine basin. Of further importance is the period of each cycle during which lacustrine conditions, and therefore lake level controlled accommodation, existed.

  11. 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.

  12. Extreme host plant conservatism during at least 20 million years of host plant pursuit by oak gallwasps.

    PubMed

    Stone, Graham N; Hernandez-Lopez, Antonio; Nicholls, James A; di Pierro, Erica; Pujade-Villar, Juli; Melika, George; Cook, James M

    2009-04-01

    Diversification of insect herbivores is often associated with coevolution between plant toxins and insect countermeasures, resulting in a specificity that restricts host plant shifts. Gall inducers, however, bypass plant toxins and the factors influencing host plant associations in these specialized herbivores remain unclear. We reconstructed the evolution of host plant associations in Western Palaearctic oak gallwasps (Cynipidae: Cynipini), a species-rich lineage of specialist herbivores on oak (Quercus). (1) Bayesian analyses of sequence data for three genes revealed extreme host plant conservatism, with inferred shifts between major oak lineages (sections Cerris and Quercus) closely matching the minimum required to explain observed diversity. It thus appears that the coevolutionary demands of gall induction constrain host plant shifts, both in cases of mutualism (e.g., fig wasps, yucca moths) and parasitism (oak gallwasps). (2) Shifts between oak sections occurred independently in sexual and asexual generations of the gallwasp lifecycle, implying that these can evolve independently. (3) Western Palaearctic gallwasps associated with sections Cerris and Quercus diverged at least 20 million years ago (mya), prior to the arrival of oaks in the Western Palaearctic from Asia 5-7 mya. This implies an Asian origin for Western Palaearctic gallwasps, with independent westwards range expansion by multiple lineages.

  13. 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.

  14. 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.

  15. Changes in ectomycorrhizal fungal community composition and declining diversity along a 2-million-year soil chronosequence.

    PubMed

    Albornoz, Felipe E; Teste, François P; Lambers, Hans; Bunce, Michael; Murray, Dáithí C; White, Nicole E; Laliberté, Etienne

    2016-10-01

    Ectomycorrhizal (ECM) fungal communities covary with host plant communities along soil fertility gradients, yet it is unclear whether this reflects changes in host composition, fungal edaphic specialization or priority effects during fungal community establishment. We grew two co-occurring ECM plant species (to control for host identity) in soils collected along a 2-million-year chronosequence representing a strong soil fertility gradient and used soil manipulations to disentangle the effects of edaphic properties from those due to fungal inoculum. Ectomycorrhizal fungal community composition changed and richness declined with increasing soil age; these changes were linked to pedogenesis-driven shifts in edaphic properties, particularly pH and resin-exchangeable and organic phosphorus. However, when differences in inoculum potential or soil abiotic properties among soil ages were removed while host identity was held constant, differences in ECM fungal communities and richness among chronosequence stages disappeared. Our results show that ECM fungal communities strongly vary during long-term ecosystem development, even within the same hosts. However, these changes could not be attributed to short-term fungal edaphic specialization or differences in fungal inoculum (i.e. density and composition) alone. Rather, they must reflect longer-term ecosystem-level feedback between soil, vegetation and ECM fungi during pedogenesis. PMID:27480679

  16. 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

  17. Seventy-five-million-year-old tropical tetra-like fish from Canada tracks Cretaceous global warming.

    PubMed

    Newbrey, M G; Murray, A M; Wilson, M V H; Brinkman, D B; Neuman, A G

    2009-11-01

    Newly discovered fossil fish material from the Cretaceous Dinosaur Park Formation of Alberta, Canada, documents the presence of a tropical fish in this northern area about 75 million years ago (Ma). The living relatives of this fossil fish, members of the Characiformes including the piranha and neon tetras, are restricted to tropical and subtropical regions, being limited in their distribution by colder temperatures. Although characiform fossils are known from Cretaceous through to Cenozoic deposits, none has been reported previously from North America. The modern distribution of characiforms in Mexico and southern Texas in the southernmost United States is believed to have been the result of a relatively recent colonization less than 12 Ma. The new Canadian fossils document the presence of these fish in North America in the Late Cretaceous, a time of significantly warmer global temperatures than now. Global cooling after this time apparently extirpated them from the northern areas and these fishes only survived in more southern climes. The lack of early Cenozoic characiform fossils in North America suggests that marine barriers prevented recolonization during warmer times, unlike in Europe where Eocene characiform fossils occur during times of global warmth.

  18. 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.

  19. Seventy-five-million-year-old tropical tetra-like fish from Canada tracks Cretaceous global warming

    PubMed Central

    Newbrey, M. G.; Murray, A. M.; Wilson, M. V. H.; Brinkman, D. B.; Neuman, A. G.

    2009-01-01

    Newly discovered fossil fish material from the Cretaceous Dinosaur Park Formation of Alberta, Canada, documents the presence of a tropical fish in this northern area about 75 million years ago (Ma). The living relatives of this fossil fish, members of the Characiformes including the piranha and neon tetras, are restricted to tropical and subtropical regions, being limited in their distribution by colder temperatures. Although characiform fossils are known from Cretaceous through to Cenozoic deposits, none has been reported previously from North America. The modern distribution of characiforms in Mexico and southern Texas in the southernmost United States is believed to have been the result of a relatively recent colonization less than 12 Ma. The new Canadian fossils document the presence of these fish in North America in the Late Cretaceous, a time of significantly warmer global temperatures than now. Global cooling after this time apparently extirpated them from the northern areas and these fishes only survived in more southern climes. The lack of early Cenozoic characiform fossils in North America suggests that marine barriers prevented recolonization during warmer times, unlike in Europe where Eocene characiform fossils occur during times of global warmth. PMID:19675010

  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. PMID:15148598

  1. 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.

  2. 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.

  3. "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. PMID:26484593

  4. Early hominid dental pathology: interproximal caries in 1.5 million-year-old Paranthropus robustus from Swartkrans.

    PubMed

    Grine, F E; Gwinnett, A J; Oaks, J H

    1990-01-01

    Carious lesions on the mesial and distal aspects of a RM1 of a young adult 'robust' australopithecine. Paranthropus robustus, are described. The specimen is from Member 1 sediments of the Swartkrans cave, which are dated to between about 1.8 and 1.5 million years before present. The mesial lesion, located cervically, had progressed further than the two distal lesions, which were situated along the cervix and in the enamel of the interproximal contact facet. This is the third specimen of P. robustus to be discovered with dental caries, but the other two cases were associated with occlusal and buccal enamel hypoplasia. Caries is present in less than about 3.0% of the approx. 116-128 P. robustus specimens at Swartkrans, and this incidence is noticeably lower than in the small Homo erectus sample from the same site. While this difference may simply be a sampling artefact, it may reflect dietary differences between these two synchronic and presumably sympatric early hominid species. PMID:2196866

  5. SeizAlert could give patients 4.5 hour warning of seizure

    SciTech Connect

    Dr. Lee Hively and Kara Kruse

    2009-01-16

    One percent of Americans, 3 million people, suffer from epilepsy. And their lives are about to be dramatically changed by scientists at Oak Ridge National Laboratory. For 15 years, Dr. Lee Hively has been working on "SeizAlert", a seizure-detecting device that resembles a common PDA. "It allows us to analyze scalp brain waves and give us up to 4.5 hours' forewarning of that event," he said. With the help of partner Kara Kruse, he's now able to help patients predict the previously unpredictable.

  6. SeizAlert could give patients 4.5 hour warning of seizure

    ScienceCinema

    Dr. Lee Hively and Kara Kruse

    2016-07-12

    One percent of Americans, 3 million people, suffer from epilepsy. And their lives are about to be dramatically changed by scientists at Oak Ridge National Laboratory. For 15 years, Dr. Lee Hively has been working on "SeizAlert", a seizure-detecting device that resembles a common PDA. "It allows us to analyze scalp brain waves and give us up to 4.5 hours' forewarning of that event," he said. With the help of partner Kara Kruse, he's now able to help patients predict the previously unpredictable.

  7. 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.

  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. PMID:24153304

  9. 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

  10. 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. PMID:27194702

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 43 CFR 4150.4-5 - Sale.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Sale. 4150.4-5 Section 4150.4-5 Public... Grazing Use § 4150.4-5 Sale. If the livestock are not redeemed on or before the date and time fixed for their sale, they shall be offered at public sale to the highest bidder by the authorized officer...

  19. 43 CFR 4150.4-5 - Sale.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Sale. 4150.4-5 Section 4150.4-5 Public... Grazing Use § 4150.4-5 Sale. If the livestock are not redeemed on or before the date and time fixed for their sale, they shall be offered at public sale to the highest bidder by the authorized officer...

  20. 43 CFR 4150.4-5 - Sale.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Sale. 4150.4-5 Section 4150.4-5 Public... Grazing Use § 4150.4-5 Sale. If the livestock are not redeemed on or before the date and time fixed for their sale, they shall be offered at public sale to the highest bidder by the authorized officer...

  1. 43 CFR 4150.4-5 - Sale.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Sale. 4150.4-5 Section 4150.4-5 Public... Grazing Use § 4150.4-5 Sale. If the livestock are not redeemed on or before the date and time fixed for their sale, they shall be offered at public sale to the highest bidder by the authorized officer...

  2. Cape Wanbrow: A stack of Surtseyan-style volcanoes built over millions of years in the Waiareka-Deborah volcanic field, New Zealand

    NASA Astrophysics Data System (ADS)

    Moorhouse, B. L.; White, J. D. L.; Scott, J. M.

    2015-06-01

    Volcanic fields typically include many small, monogenetic, volcanoes formed by single eruptions fed by short-lived magma plumbing systems that solidify after eruption. The Cape Wanbrow coastline of the northeast Otago region in the South Island of New Zealand exposes an Eocene-Oligocene intraplate basaltic field that erupted in Surtseyan style onto a submerged continental shelf, and the stratigraphy of Cape Wanbrow suggests that eruptions produced multiple volcanoes whose edifices overlapped within a small area, but separated by millions of years. The small Cape Wanbrow highland is shown to include the remains of 6 volcanoes that are distinguished by discordant to locally concordant inter-volcano contacts marked by biogenic accumulations or other slow-formed features. The 6 volcanoes contain several lithofacies associations: (a) the dominantly pyroclastic E1 comprising well-bedded tuff and lapilli-tuff, emplaced by traction-dominated unsteady, turbulent high-density currents; (b) E2, massive to diffusely laminated block-rich tuff deposited by grain-dominant cohesionless debris flows; (c) E3, broadly cross-stratified tuff with local lenses of low- to high-angle cross-stratification which was deposited by either subaerial pyroclastic currents or subaqueously by unstable antidune- and chute-and-pool-forming supercritical flows; (d) E4, very-fine- to medium-grained tuff deposited by turbidity currents; (e) E5, bedded bioclast-rich tuff with increasing glaucony content upward, emplaced by debris flows; (f) E6, pillow lava and inter-pillow bioclastic sediment; and (g) E7, hyaloclastite breccia. These lithofacies associations aid interpretation of the eruptive evolution of each separate volcano, which in turn grew and degraded during build-up of the overall volcanic pile. Sedimentary processes played a prominent role in the evolution of the volcanic pile with both syn- and post-eruptive re-mobilization of debris from the growing pile of primary pyroclastic deposits of

  3. 28 CFR 4.5 - Character endorsements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 1 2013-07-01 2013-07-01 false Character endorsements. 4.5 Section 4.5 Judicial Administration DEPARTMENT OF JUSTICE PROCEDURE GOVERNING APPLICATIONS FOR CERTIFICATES OF... reputation in his community or in his circle of business or social acquaintances. Each letter or other...

  4. 28 CFR 4.5 - Character endorsements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 1 2014-07-01 2014-07-01 false Character endorsements. 4.5 Section 4.5 Judicial Administration DEPARTMENT OF JUSTICE PROCEDURE GOVERNING APPLICATIONS FOR CERTIFICATES OF... reputation in his community or in his circle of business or social acquaintances. Each letter or other...

  5. Downsizing the pelagic carbonate factory: Impacts of calcareous nannoplankton evolution on carbonate burial over the past 17 million years

    NASA Astrophysics Data System (ADS)

    Suchéras-Marx, Baptiste; Henderiks, Jorijntje

    2014-12-01

    Cenozoic deep-sea carbonates ("calcareous oozes") are predominantly biogenic in origin and offer detailed records of the evolution of calcifying plankton groups, such as coccolithophores and foraminifera. The size and abundance of calcifying plankton determine the strength of the calcium carbonate "pump" in the open ocean, which acts as a short-term source of CO2, while the burial of pelagic carbonates serves as a long-term sink of carbon. Here, we show how the macroevolutionary size decrease in calcareous nannoplankton (coccoliths and calcareous nannoliths) has affected burial rates of calcareous ooze over the past 17 million years. We quantified nannofossil carbonate burial rates (g CaCO3/m2/yr) at five DSDP/ODP sites in the Atlantic, Indian, and Western Pacific oceans. The proportion of nannofossil-dominated fine fraction carbonate (< 38 μm) and its mass accumulation rates were regionally and temporally variable, but our combined data reveal globally consistent long-term trends. Mean nannofossil carbonate mass decreased about four-fold between 9 and 4 Ma, but this had little or only minor impact on the burial of pelagic carbonate until ~ 4 Ma. After ~ 4 Ma, when small-sized coccolith-bearing species prevailed, nannofossil carbonate burial rates decreased by one order of magnitude to the lowest values during the Pleistocene. In contrast, mass accumulation rates of the foraminifera-dominated > 38 μm fraction remained stable over the past 17 Myr. This suggests that changes in the deposition of calcareous ooze were primarily driven by calcareous nannoplankton, and that foraminifera did not compensate for the lower nannofossil-carbonate accumulation rates since the Pliocene. Despite a deepening of the lysocline over the past 4 Myr, global pelagic carbonate mass accumulation likely decreased. Whether, or how, this may relate to changes in weathering or other components within the long-term carbonate cycle remains unclear. Explanations for the macroevolutionary size

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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. PMID:23404127

  11. 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

  12. Impact of large atmospheric CO2 decline on marine life and sedimentation 375-325 million years ago

    NASA Astrophysics Data System (ADS)

    Riding, R.

    2010-12-01

    Mass Extinctions, widespread deposition of black shale and carbonate mud mounds, and decline in atmospheric CO2 occurred during the Late Devonian-Early Mississippian (LDEM), 375-325 million years ago. These at first sight unrelated events can be linked by the response of phytoplankton to reduced CO2 supply. pCO2 declined from >10 to <5 times present atmospheric level (PAL). In experiments, reduction on this scale induces CO2-concentrating mechanisms (CCMs) in present-day cyanobacteria. CCMs act to maintain photosynthesis, but also have effects that parallel LDEM events. First, by helping to overcome carbon limitation, CCMs increase primary productivity, promoting bloom conditions, anoxia and black shale accumulation. Second, so long as carbonate saturation state is sufficiently elevated, cyanobacterial CCMs also promote water-column precipitation of fine-grained CaCO3 (whitings) due to active import of HCO3- raising pH adjacent to cells. Intense whitings would provide a sustained source of fine-grained carbonate for mud mound formation. Third, by affecting the success of other phytoplankton in which CCMs are less well-developed or lacking, CCM induction by cyanobacteria could have promoted Late Devonian acritarch extinction. It is also possible that toxic blooms of cyanobacteria, generated by CCMs, contributed to Late Devonian extinction of very shallow water reef and other communities. Further evidence consistent with CCM induction and proliferation of planktic cyanobacteria during the LDEM includes increases in cyanobacterial biomarkers, cyanobacterial sheath-calcification, and δ13C isotope values. Carbonate mud mound abundance increased in the Late Devonian, reaching its Paleozoic acme in the Early Mississippian. The source of this mud and its unusual abundance at this time has defied resolution. It has been suggested that the carbonate mud was largely precipitated in situ on the mounds. However,this mechanism is inconsistent with bedded mound structure, leaves

  13. Earth's eccentricity cycles and Indian Summer Monsoon variability over the past 2 million years: Evidence from deep-sea benthic foraminifer

    NASA Astrophysics Data System (ADS)

    Gupta, Anil K.; Dhingra, Hitesh; Mélice, Jean-Luc; Anderson, David M.

    Spectral analysis of a Uvigerina proboscidea time series from DSDP Site 214 using the Lomb-Scargle method for unevenly sampled data, exhibits two dominant power peaks at 412 and 94 kyrs over the last 2 million years, which correspond to the Earth's eccentricity cycles. The results indicate that the SW monsoon varied at about 100 kyr and 400 kyr periodicities within Earth's eccentricity domain (Milankovitch range) over the past 2 million years. Wavelet transform analysis reveals the non-stationary nature of monsoon upwelling over this interval. The amplitude of the 400 kyr cycle in the U. proboscidea time series began to increase at ∼900 kyrs as has also been observed in few recent studies. We do not see a strong relation between eccentricity highs and intense summer monsoons over the studied interval.

  14. 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

  15. 1,2,4,5-Tetrachlorobenzene

    Integrated Risk Information System (IRIS)

    1,2,4,5 - Tetrachlorobenzene ; CASRN 95 - 94 - 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 Nonca

  16. Imprint of Climate Variability on Mesozoic Fossil Tree Rings: Evidences of Solar Activity Signals on Environmental Records Around 200 Million Years Ago?

    NASA Astrophysics Data System (ADS)

    Prestes, A.; Rigozo, N. R.; Nordemann, D. J. R.; Echer, E.; Vieira, L. E. A.; Souza Echer, M. P.; Wrasse, C. M.; Guarnieri, F. L.

    2014-08-01

    Evidence of the solar activity modulation of the Earth's climate has been observed on several parameters, from decadal to millennial time scales. Several proxies have been used to reconstruct the paleoclimate as well as the solar activity. The paleoclimate reconstructions are based on direct and/or indirect effects of global and regional climate conditions. The solar activity reconstructions are based on the production of the 14C isotope due to the interaction of cosmic ray flux and the Earth's atmosphere. Because trees respond to climate conditions and store 14C, they have been used as proxies for both for climate and solar activity reconstructions. The imprints of solar activity cycles dating back to 10,000 years ago have been observed on tree-ring samples using 14C data, and those dating back to 20 million years ago have been analyzed using fossil tree-growth rings. All this corresponds to the Cenozoic era. However, solar activity imprints on tree rings from earlier than that era have not been investigated yet. In this work, we showed that tree rings from the Mesozoic Era (of ~200 million years ago) recorded 11- and 22-year cycles, which may be related to solar activity cycles, and that were statistically significant at the 95 % confidence level. The fossil wood was collected in the southern region of Brazil. Our analysis of the fossils' tree-ring width series power spectra showed characteristics similar to the modern araucaria tree, with a noticeable decadal periodicity. Assuming that the Earth's climate responds to solar variability and that responses did not vary significantly over the last ~200 million years, we conclude that the solar-climate connection was likely present during the Mesozoic era.

  17. 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.

  18. 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T)

    Integrated Risk Information System (IRIS)

    2,4,5 - Trichlorophenoxyacetic acid ( 2,4,5 - T ) ; CASRN 93 - 76 - 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

  19. 2(2,4,5-Trichlorophenoxy) propionic acid (2,4,5-TP)

    Integrated Risk Information System (IRIS)

    2 ( 2,4,5 - Trichlorophenoxy ) propionic acid ( 2,4,5 - TP ) ; CASRN 93 - 72 - 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 ( Hea

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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. PMID:26644580

  5. 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. PMID:26690569

  6. The last ~1 million years of carbonatite volcanism in northern Tanzania; last gasp of a decaying rift?

    NASA Astrophysics Data System (ADS)

    Jones, A.

    2003-04-01

    Continued monitoring of volcanic activity at Oldoinyo Lengai for the last ~35 years suggests that this central volcano has become a highly evolved low temperature/low volume carbonatite-nephelinite system. The sustained intermingling of silicate and carbonatitic eruptions for most of this volcano's history contrasts sharply with the two-stage sequential development of neighbouring Kerimasi (nephelinite then carbonatite). The footprint of the older Kerimasi volcano is effected by active faulting of earlier flood lavas along the west rift wall. The mineralogy, petrology and geochemistry of both volcanos generally conform with the LeBas model of carbonatite-nephelinite volcanism for the eastern arm of the EAR. However, their overall differences in bulk chemistry suggest that their ~15 km horizontal separation at the surface, reflects compositional heterogeneity of the mantle source over a similar length scale. This is consistent with primary melt segregation at relatively shallow mantle depths, and crustal delivery along pipe-like conduits with minimal lateral transport. The surrounding rift valley floor is pock-marked with numerous small volcanic structures, such as tuff cones, craters and minor lava flows. The ages of these minor volcanos are bracketed by the two larger central volcanos, and also contain both carbonatite and alkaline silicate magmas; they extend the compositional range and suggest deeper sources for periodic small volume primary melilitite magmas. Their xenolith populations are consistent with an extended history of metasomatised mantle peridotites characterised by increasing amphibole, mica, and clinopyroxene at the expense of orthopyroxene. Megacrysts and cumulate-textured xenoliths are also consistent with repeated occupation of vertical conduits and local sidewall crystallisation at depths close to the Moho. Overall, the recent volcanic activity represents highly evolved small volume batches of mantle melts with high carbonate and CO2, and

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. A perspective on 10-years HTS experience at the Walter and Eliza Hall Institute of Medical Research - eighteen million assays and counting.

    PubMed

    Lackovic, Kurt; Lessene, Guillaume; Falk, Hendrik; Leuchowius, Karl-Johan; Baell, Jonathan; Street, Ian

    2014-03-01

    The Walter and Eliza Hall Institute of Medical Research (WEHI) is Australia's longest serving medical research institute. WEHI's High Throughput Screening (HTS) Facility was established in 2003 with $5 million of infrastructure funds invested by WEHI, and the Victorian State Government's Strategic Technology Initiative through Bio21 Australia Ltd. The Facility was Australia's first truly academic HTS facility and was one of only a handful operating in publicly funded institutions worldwide at that time. The objectives were to provide access to enabling HTS technologies, such as assay design, liquid handling automation, compound libraries and expertise to promote translation of basic research in a national setting that has a relatively young biotech sector and does not have a big Pharma research presence. Ten years on and the WEHI HTS Facility has participated in over 92 collaborative projects, generated over 18 million data points, and most importantly, projects that began in the Facility have been commercialized successfully (due to strong ties with Business Development and emphasis on intellectual property management) and now have molecules progressing in clinical trials.

  13. Quantitative restoration of 1 million years of crustal extension in the Gulf of Corinth rift, central Greece

    NASA Astrophysics Data System (ADS)

    Mann, P.; Dowla, N.

    2013-12-01

    The Gulf of Corinth (GOC) rifted zone of central Greece is accessible for both marine seismic data acquisition and onland field studies and has been the focus of many types of active rift research for the past 50 years. The purpose of this study is to: 1) compile all existing marine seismic reflection data from the GOC and geologic map data from adjacent onland rifts exposed south of the GOC; 2) create four digitized dip direction cross sections crossing the western (1) and central (3) GOC that included major faults and sedimentary sequences extracted from compiled onland and offshore data; 3) use 2D-MOVE software to restore these present-day cross sections to their undeformed state, adhering to line length and area balancing structural geology principles; 4) compare calculated extension amounts to previous structural studies that proposed extensional amounts using other methods. Previous work in the GOC region has led to controversies in the following topics which all impact how we construct present-day cross sections: 1) whether normal faults in the GOC sole onto a low-angle detachment or are thick-skinned faults extending deep into the crust; previous microearthquake surveys of seismogenic normal faults of the western GOC support the existence of a low-angle detachment whose fault dip and depth to detachment were used for our cross sections; 2) the listric versus planar shapes of normal faults; deep-penetration marine seismic data supports the presence of listric fault shapes with dips extending to depths of 10 km; and 3) the age of pre- and syn-rift sediments in the GOC and onland rifts to the south; we followed the age estimates of Taylor et al. (2011) for a two-stage rift history with Stage 1 from 1 Ma-700 ka and Stage 2 from 700 ka to present. Results from the four restored cross sections include: 1) the narrow, 1.35-km-wide marine strait of the western GOC exhibits the least amount of extension (1.8 km) with the oldest normal faults initiating south of GOC

  14. Synthesis of 2-vinyl-3,4,5-trichlorothiophene and 3,4,5-trichlorothenyl acrylates

    SciTech Connect

    Akopyan, A.N.; Saakyan, A.A.; Gavalyan, V.B.; Smbatyan, A.G.; Darbinyan, E.G.

    1988-12-20

    Preparative methods were developed for the production of 2-vinyl-3,4,5-trichlorothiophene from 2-chloromethyl-3,4,5-trichlorothiophene by the Wittig reaction of a two-phase system and by catalytic dehydration of 2-(/alpha/-hydroxyethyl)-3,4,5-trichlorothiophene. In reaction with an aqueous solution of formaldehyde in the two-phase water-chloroform system in the presence of sodium carbonate 3,4,5-trichloroenyltrihenylphosphonoium chloride gives vinylthiophene (I) with an almost quantitative yield (93-95%). The process takes place under mild conditions (40/degree/C) and without a specially added phase-transfer catalyst, since the role of latter is evidently played by the phosphonium salt itself. 2-(/alpha/-Hydroxylethyl)-3,4,5-trichlorothiophene is formed by the reduction of the ketone (III) with sodium borohydride in methanol at 40/degree/C with a yield of 87%. The dehydration of the alcohol takes place at 180-200/degree/C in the presence of potassium bisulfate. The methods developed for the production of 2-vinylthiophene can be recommended as preparative methods on account of their simplicity, mild conditions, and high yields.

  15. Microstructural examination of irradiated V-(4-5%)Cr-(4-5%)Ti.

    SciTech Connect

    Gelles, D. S.

    1998-05-04

    Microstructural examination results are reported for two heats of V-(4-5%) Cr-(4-5%)Ti irradiated in the EBR-II X530 experiment to 4.5 dpa at {approximately}400 C to provide an understanding of the microstructural evolution that may be associated with degradation of mechanical properties. Fine precipitates were observed in high density intermixed with small defect clusters for all conditions examined following the irradiation. The irradiation-induced precipitation does not appear to be affected by preirradiation heat treatment at 950-1125 C. There was no evidence for a significant density of large (diameter >10 nm) dislocation loops or network dislocations. Analytical investigations successfully demonstrated that the precipitates were enriched in titanium, depleted in vanadium and contained no nitrogen. These results are discussed in terms of future alloy development options.

  16. Thermophysical and mechanical properties of V-(4-5)%Cr-(4-5)%Ti alloys

    SciTech Connect

    Zinkle, S.J.

    1998-03-01

    Solid solution V-Cr-Ti alloys exhibit a good combination of high thermal conductivity, adequate tensile strength, and low thermal expansion. The key thermophysical and mechanical properties for V-(4-5)%Cr-(4-5)%Ti alloys are summarized in this report. Some of these data are available in the ITER Materials Properties Handbook (IMPH), whereas other data have been collected from recent studies. The IMPH is updated regularly, and should be used as the reference point for design calculations whenever possible.

  17. Tensile properties of V-(4-5)Cr-(4-5)Ti alloys

    SciTech Connect

    Chung, H.M.; Nowicki, L.; Busch, D.; Smith, D.L.

    1996-04-01

    The current focus of the U.S program of research on V-base alloys is on V-(4-5)Cr(4-5)Ti that contains 500-1000 wppm Si. in this paper, we present experimental results on baseline tensile properties of two laboratory-scale heats of this alloy and of a 500-kg production heat of V-4Cr-4Ti (heat 832665) that were measured at 23-700 C. Both the production- and laboratory scale heats of the reference alloy V-4Cr-4Ti exhibited excellent tensile properties at temperatures up to {approx}650{degrees}C.

  18. Microstructural examination of V-(4-5%) Cr-(4-5%)Ti irradiated in X530

    SciTech Connect

    Gelles, D.S.; Chung, H.M.

    1997-08-01

    Microstructural examination results are reported for two heats of V-(4-5%)Cr-(4-5%)Ti irradiated in the X530 experiment to {approximately}400{degrees}C to provide an understanding of the microstructural evolution that may be associated with degradation of mechanical properties. Fine precipitates were observed in high density intermixed with small defect clusters for all conditions examined following the irradiation. The irradiation-induced precipitation does not appear to be affected by preirradiation heat treatment at 950-1125{degrees}C. There was no evidence for a significant density of large (diameter >10 nm) dislocation loops or network dislocations.

  19. 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.

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

    PubMed

    Kasting, J F

    1984-12-01

    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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Microstructural examination of irradiated V-(4-5%)Cr-(4-5%)Ti

    SciTech Connect

    Gelles, D.S.; Rice, P.M.; Zinkle, S.J.; Chung, H.M.

    1998-03-01

    Microstructural examination results are reported for two heats of V-(4-5%)Cr-(4-5%)Ti irradiated in the EBR-II X530 experiment to {approximately}4 dpa at {approximately}400 C to provide an understanding of the microstructural evolution that may be associated with degradation of mechanical properties. Fine precipitates were observed in high density intermixed with small defect clusters for all conditions examined following the irradiation. The irradiation-induced precipitation does not appear to b affected by preirradiation heat treatment at 950--1125 C. There was no evidence for a significant density of large (diameter >10 nm) dislocation loops or network dislocations. Analytical investigators successfully demonstrated that the precipitates were enriched in titanium, depleted in vanadium and contained no nitrogen.

  6. Regional diversity patterns in African bovids, hyaenids, and felids during the past 3 million years: the role of taphonomic bias and implications for the evolution of Paranthropus

    NASA Astrophysics Data System (ADS)

    Patterson, David B.; Faith, J. Tyler; Bobe, René; Wood, Bernard

    2014-07-01

    Reconstructing patterns of Plio-Pleistocene mammalian faunal exchange between eastern and southern Africa may help us to better understand patterns of evolution within the hominin clade. However, differences in geological context, taphonomic history and collection methods, as well as a lack of a precise chronology in one of the regions, complicate attempts to compare the faunas of the two regions, but access to new comprehensive datasets encouraged us to re-examine this critical time period in the African paleontological record. In this study, we examine the biogeographic histories of three terrestrial African mammalian families whose fossil records span the past 3 million years to test hypotheses related to the evolutionary history of the hominin genus Paranthropus. We used presence/absence data for 117 species from 38 genera within the family Bovidae and 34 species from 15 genera within the families Hyaenidae and Felidae from 52 eastern African and 40 southern African fossil localities. These assemblages were placed into 500 ka time slices and compared at both the genus and species level using the Jaccard index of faunal similarity. Our findings indicate that sampling biases have more effect on the patterns of interchange between eastern and southern African Bovidae than they do the patterns of interchange seen in the Hyaenidae and Felidae. However, even when these biases are taken into account there are persistent differences in the degree of interchange within and between these families. These findings suggest that mammalian groups (including hominins) can have very different histories of exchange between eastern and southern Africa over the past 3 million years. There is no a priori reason why any of the three families we examined is a suitable proxy for the eastern and southern African hyper-megadont and megadont hominin taxa presently included in Paranthropus, but of the three we suggest that the Bovidae is likely to come closest to being an appropriate

  7. Coeval 40Ar/39Ar Ages of 65.0 Million Years Ago from Chicxulub Crater Melt Rock and Cretaceous-Tertiary Boundary Tektites.

    PubMed

    Swisher, C C; Grajales-Nishimura, J M; Montanari, A; Margolis, S V; Claeys, P; Alvarez, W; Renne, P; Cedillo-Pardoa, E; Maurrasse, F J; Curtis, G H; Smit, J; McWilliams, M O

    1992-08-14

    (40)Ar/(39)Ar dating of drill core samples of a glassy melt rock recovered from beneath a massive impact breccia contained within the 180-kilometer subsurface Chicxulub crater in Yucatán, Mexico, has yielded 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 (40)Ar/(39)Ar 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 (40)Ar/(39)Ar ages, in conjunction with geochemical and petrological similarities, strengthen the recent 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.

  8. 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.; Edwards, Nicholas P.; Sellers, William I.; Bergmann, Uwe; Sokaras, Dimosthenis; Alonso-Mori, Roberto; Ignatyev, Konstantin; van Veelen, Arjen; et al

    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

  9. 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.

  10. 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.

  11. 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. PMID:27097031

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  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. PMID:27194696

  20. 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

    2015-01-01

    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

  1. Coeval 40Ar/39Ar Ages of 65.0 Million Years Ago from Chicxulub Crater Melt Rock and Cretaceous-Tertiary Boundary Tektites.

    PubMed

    Swisher, C C; Grajales-Nishimura, J M; Montanari, A; Margolis, S V; Claeys, P; Alvarez, W; Renne, P; Cedillo-Pardoa, E; Maurrasse, F J; Curtis, G H; Smit, J; McWilliams, M O

    1992-08-14

    (40)Ar/(39)Ar dating of drill core samples of a glassy melt rock recovered from beneath a massive impact breccia contained within the 180-kilometer subsurface Chicxulub crater in Yucatán, Mexico, has yielded 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 (40)Ar/(39)Ar 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 (40)Ar/(39)Ar ages, in conjunction with geochemical and petrological similarities, strengthen the recent 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. PMID:17789640

  2. A New Method for Reconstructing Sea-Level and Deep-Sea-Temperature Variability over the Past 5.3 Million Years

    NASA Astrophysics Data System (ADS)

    Rohling, E. J.

    2014-12-01

    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 (d18O) 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. We have recently presented 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. A serious of caveats applies to this new method, especially in older times of its application, as is always the case with new methods. Independent validation exercises are needed to elucidate where consistency exists, and where solutions drift away from each other. A key observation from our new method is that a large temporal offset existed 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. This observation relies on relative changes within the dataset, which are more robust than absolute values. I will discuss our method and its main caveats and avenues for improvement.

  3. Degradation of 4,5-dichloroguaiacol by soil microorganisms.

    PubMed

    González, B; Brezny, R; Herrera, M; Joyce, T W

    1995-09-01

    No microorganisms could be isolated from chemostats or from a soil column fed with 4,5-dichloroguaiacol as the only carbon source. If guaiacol was added to chemostats with 4,5-dichloroguaiacol, either soil microbial consortia or guaiacol-degrading bacteria could dechlorinate the 4,5-dichloroguaiacol provided it was <0.2MM. A microbial consortium from farm soil removed 4,5-dichloroguaiacol under aerobic or anoxic conditions, with or without chlorolignin. Dichlorocatechol was the only 4,5-dichloroguaiacol-derived metabolite detected. In aerobic incubations, 4,5-dichlorocatechol was further degraded whereas under anoxic conditions it accumulated. PMID:24414909

  4. 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.

  5. 45 CFR 4.5 - Effect of regulations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 1 2011-10-01 2011-10-01 false Effect of regulations. 4.5 Section 4.5 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION SERVICE OF PROCESS § 4.5 Effect of regulations. The regulations in this part are intended solely to identify Department officials who...

  6. 12 CFR 4.5 - District and field offices.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false District and field offices. 4.5 Section 4.5... EXAMINERS Organization and Functions § 4.5 District and field offices. (a) District offices. Each district... Dakota, Utah, Washington, Wyoming, and Guam. (b) Field offices and duty stations. Field offices and...

  7. 10 CFR 4.5 - Communications and reports.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Communications and reports. 4.5 Section 4.5 Energy NUCLEAR... FINANCIAL ASSISTANCE FROM THE COMMISSION General Provisions § 4.5 Communications and reports. Except as otherwise indicated, communications and reports relating to this part may be sent to the NRC by...

  8. 10 CFR 4.5 - Communications and reports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Communications and reports. 4.5 Section 4.5 Energy NUCLEAR... FINANCIAL ASSISTANCE FROM THE COMMISSION General Provisions § 4.5 Communications and reports. Except as otherwise indicated, communications and reports relating to this part may be sent to the NRC by...

  9. 10 CFR 4.5 - Communications and reports.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Communications and reports. 4.5 Section 4.5 Energy NUCLEAR... FINANCIAL ASSISTANCE FROM THE COMMISSION General Provisions § 4.5 Communications and reports. Except as otherwise indicated, communications and reports relating to this part may be sent to the NRC by...

  10. 10 CFR 4.5 - Communications and reports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Communications and reports. 4.5 Section 4.5 Energy NUCLEAR... FINANCIAL ASSISTANCE FROM THE COMMISSION General Provisions § 4.5 Communications and reports. Except as otherwise indicated, communications and reports relating to this part may be sent to the NRC by...

  11. 10 CFR 4.5 - Communications and reports.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Communications and reports. 4.5 Section 4.5 Energy NUCLEAR... FINANCIAL ASSISTANCE FROM THE COMMISSION General Provisions § 4.5 Communications and reports. Except as otherwise indicated, communications and reports relating to this part may be sent to the NRC by...

  12. 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

  13. 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. PMID:23522822

  14. 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.

  15. First hominine remains from a ~1.0 million year old bone bed at Cornelia-Uitzoek, Free State Province, South Africa.

    PubMed

    Brink, James S; Herries, Andy I R; Moggi-Cecchi, Jacopo; Gowlett, John A J; Bousman, C Britt; Hancox, John P; Grün, Rainer; Eisenmann, Vera; Adams, Justin W; Rossouw, Lloyd

    2012-09-01

    We report here on evidence of early Homo around 1.0 Ma (millions of years ago) in the central plains of southern Africa. The human material, a first upper molar, was discovered during the systematic excavation of a densely-packed bone bed in the basal part of the sedimentary sequence at the Cornelia-Uitzoek fossil vertebrate locality. We dated this sequence by palaeomagnetism and correlated the bone bed to the Jaramillo subchron, between 1.07 and 0.99 Ma. This makes the specimen the oldest southern African hominine remains outside the dolomitic karst landscapes of northern South Africa. Cornelia-Uitzoek is the type locality of the Cornelian Land Mammal Age. The fauna contains an archaic component, reflecting previous biogeographic links with East Africa, and a derived component, suggesting incipient southern endemism. The bone bed is considered to be the result of the bone collecting behaviour of a large predator, possibly spotted hyaenas. Acheulian artefacts are found in small numbers within the bone bed among the fossil vertebrates, reflecting the penecontemporaneous presence of people in the immediate vicinity of the occurrence. The hominine tooth was recovered from the central, deeper part of the bone bed. In size, it clusters with southern African early Homo and it is also morphologically similar. We propose that the early Homo specimen forms part of an archaic component in the fauna, in parallel with the other archaic faunal elements at Uitzoek. This supports an emergent pattern of archaic survivors in the southern landscape at this time, but also demonstrates the presence of early Homo in the central plains of southern Africa, beyond the dolomitic karst areas. PMID:22840572

  16. 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

  17. 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

  18. 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

  19. Synthesis and biological activity of substituted-4,5,6,7-tetrahydrothieno pyridines: a review.

    PubMed

    Sangshetti, Jaiprakash N; Zambare, Abhay S; Khan, Firoz A Kalam; Gonjari, Indrajeet; Zaheer, Zahid

    2014-01-01

    4,5,6,7-Tetrahydrothieno pyridine is an important class of heterocyclic nucleus. Various 4,5,6,7-tetrahydrothieno pyridine derivatives have been synthesized and evaluated for various biological activities in different models with desired findings. Some analogs have shown potent biological activities and may be considered as lead molecule for the development of future drugs. Number of drug molecules are available in the market and many molecules are in clinical development containing 4,5,6,7-tetrahydrothieno pyridine nucleus as an important core. This review is an attempt to organize the chemical and biological aspects of 4,5,6,7-tetrahydrothieno pyridine analogs reported in last 20 year to till date. Review mainly focuses on the important role of the core in synthesis of drug or drug intermediates giving emphasis on synthetic schemes and biological activities of the different 4,5,6,7-tetrahydrothieno pyridine analogs. PMID:25373848

  20. Elimination of 2,4,5,2',4',5'-hexachlorobiphenyl by the purple sea urchin, Strongylocentrotus purpuratus, following single exposure

    SciTech Connect

    Tjeerdema, R.S.; Jacobs, R.S.

    1987-06-01

    Understanding the fate of a single PCB isomer in a resident species may aid in assessing the risk to the marine community. Therefore, the elimination of 2,4,5,2',4',5'-hexachlorobiphenyl (HCBP) by the purple sea urchin, Strongylocentrotus purpuratus, following a single exposure, was investigated. The purple sea urchin was chosen because of its economic importance and ability to proliferate in certain polluted conditions. Single exposure may best mimic the effects of intermittent oceanic incineration or disposal, and 2,4,5,2',4',5'-HCBP was chosen due to its presence in common PCB mixtures and high chlorine content, thus strong lipophilicity.

  1. 43 CFR 2650.4-5 - National forest lands.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false National forest lands. 2650.4-5 Section... Selections: Generally § 2650.4-5 National forest lands. Every conveyance which includes lands within the boundaries of a national forest shall, as to such lands, contain reservations that: (a) Until December...

  2. 43 CFR 2650.4-5 - National forest lands.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false National forest lands. 2650.4-5 Section... Selections: Generally § 2650.4-5 National forest lands. Every conveyance which includes lands within the boundaries of a national forest shall, as to such lands, contain reservations that: (a) Until December...

  3. 43 CFR 2650.4-5 - National forest lands.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false National forest lands. 2650.4-5 Section... Selections: Generally § 2650.4-5 National forest lands. Every conveyance which includes lands within the boundaries of a national forest shall, as to such lands, contain reservations that: (a) Until December...

  4. 43 CFR 2650.4-5 - National forest lands.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false National forest lands. 2650.4-5 Section... Selections: Generally § 2650.4-5 National forest lands. Every conveyance which includes lands within the boundaries of a national forest shall, as to such lands, contain reservations that: (a) Until December...

  5. 11 CFR 4.5 - Categories of exemptions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... individual. (b) Whenever a request is made which involves access to records described in 11 CFR 4.5(a)(7... Federal Elections FEDERAL ELECTION COMMISSION PUBLIC RECORDS AND THE FREEDOM OF INFORMATION ACT § 4.5... Officer, Federal Election Commission, 999 E Street, NW., Washington, DC 20463, and shall indicate...

  6. 43 CFR 1610.4-5 - Formulation of alternatives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Formulation of alternatives. 1610.4-5 Section 1610.4-5 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR GENERAL MANAGEMENT (1000) PLANNING, PROGRAMMING, BUDGETING...

  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. 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).

  9. RCP4.5: A Pathway for Stabilization of Radiative Forcing by 2100

    SciTech Connect

    Thomson, Allison M.; Calvin, Katherine V.; Smith, Steven J.; Kyle, G. Page; Volke, April C.; Patel, Pralit L.; Delgado Arias, Sabrina; Bond-Lamberty, Benjamin; Wise, Marshall A.; Clarke, Leon E.; Edmonds, James A.

    2011-07-29

    Representative Concentration Pathway (RCP) 4.5 is a scenario that stabilizes radiative forcing at 4.5 W m{sup -2} in the year 2100 without ever exceeding that value. Simulated with the Global Change Assessment Model (GCAM), RCP4.5 includes long-term, global emissions of greenhouse gases, short-lived species, and land-use-land-cover in a global economic framework. RCP4.5 was updated from earlier GCAM scenarios to incorporate historical emissions and land cover information common to the RCP process and follows a cost-minimizing pathway to reach the target radiative forcing. The imperative to limit emissions in order to reach this target drives changes in the energy system, including shifts to electricity, to lower emissions energy technologies and to the deployment of carbon capture and geologic storage technology. In addition, the RCP4.5 emissions price also applies to land use emissions; as a result, forest lands expand from their present day extent. The simulated future emissions and land use were downscaled from the regional simulation to a grid to facilitate transfer to climate models. While there are many alternative pathways to achieve a radiative forcing level of 4.5 W m{sup -2}, the application of the RCP4.5 provides a common platform for climate models to explore the climate system response to stabilizing the anthropogenic components of radiative forcing.

  10. Nuclear Ptdlns(3,4,5)P3 signaling: an ongoing story.

    PubMed

    Déléris, Paul; Gayral, Stéphanie; Breton-Douillon, Monique

    2006-06-01

    Phosphatidylinositol 3,4,5-trisphosphate (Ptdlns(3,4,5)P(3)) is linked to a variety of cellular functions, such as growth, cell survival, and differentiation. Ptdlns(3,4,5)P(3) is primarily synthesized by class I phosphoinositide 3-kinases and its hydrolysis by two 3-phosphoinositide 3-phosphatases, PTEN and SHIP proteins, leads to the production of two other second messengers, Ptdlns(4,5)P(2) and Ptdlns(3,4)P(2), respectively. Evidence accumulated over the last years strongly suggest that Ptdlns(3,4,5)P(3) is an important component of signaling pathway operating within the nucleus. Moreover, recent advances indicated that nuclear translocation of cell surface receptors could activate nuclear phosphoinositide 3-kinase suggesting a new mode of signal transduction. The aim of this review is intended to summarize the state of our knowledge on nuclear Ptdlns(3,4,5)P(3) and its metabolizing enzymes, and to highlight the emerging roles for intranuclear Ptdlns(3,4,5)P(3). PMID:16645993

  11. New 4,5-dichlorophthalhydrazidate-bridged chained coordination polymers

    SciTech Connect

    Jin, Juan; Wu, Di; Jia, Ming-Jun; Peng, Yu; Yu, Jie-Hui; Wang, Yu-Chang; Xu, Ji-Qing

    2011-03-15

    The hydrothermal self-assemblies of Pb{sup 2+}/Cd{sup 2+} salt, 4,5-dichlorophthalic acid (dcpha), N{sub 2}H{sub 4}.H{sub 2}O together with 1,10-phenanthroline.H{sub 2}O (phen) or 2,2'-bipyridine (bpy) generated two new monoacylhydrazidate-bridged 1-D chained coordination polymers [Pb{sub 2}(DCPTH){sub 4}(phen){sub 2}] 1 and [Cd{sub 3}(DCPTH){sub 2}(dcph){sub 2}(bpy){sub 2}] 2 (DCPTH=4,5-dichlorophthalhydrazidate, dcph=4,5-dichlorophthalate). The monoacylhydrazidate ligand DCPTH originated from the hydrothermal in situ acylation reaction between dcpha and N{sub 2}H{sub 4}.H{sub 2}O. In compound 1, two types of coordination modes for DCPTH are found, which link alternately the Pb(II) centers into a 1-D chain structure of compound 1 with ancillary phen molecules. In compound 2, DCPTH and dcph as the mixed bridges extend the Cd(II) centers into a 1-D chain structure of compound 2 with auxiliary bpy molecules. DCPTH in compound 2 shows a different coordination mode from those observed in compound 1. -- Graphical abstract: By applying the in situ acylation reaction between 4,5-diclorophthalic acid and N{sub 2}H{sub 4}.H{sub 2}O, two 4,5-dichlorophthalhydrazidate-bridged chained compounds [Pb{sub 2}(DCPTH){sub 4}(phen){sub 2}] and [Cd{sub 3}(DCPTH){sub 2}(dcph){sub 2}(bpy){sub 2}] (4,5-dichlorophthalhydrazidate=DCPTH, and dcph=4,5-dichlorophthalate) were hydrothermally synthesized. Display Omitted Research highlights: > In this article, we first reported the preparations and structural characterization of two examples of 4,5-dichlorophthalhydrazidate-bridged chained coordination polymers [Pb{sub 2}(DCPTH){sub 4}(phen){sub 2}] 1 and [Cd{sub 3}(DCPTH){sub 2}(dcph){sub 2}(bpy){sub 2}] 2. 4,5-dichlorophthalhydrazidate derived from the hydrothermal in situ acylation reactions between 4,5-dichlorophthalic acid and N{sub 2}H{sub 4}.H{sub 2}O. > In this article, a simple method to judge whether the polycarboxylic acid precursors have acylated into the acylhydrazidate ligands is

  12. 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. PMID:24750196

  13. 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.

  14. 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

  15. 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.

  16. 13. PRATT STREET BULKHEAD: SECTIONS 2, 3, 4, 5, AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. PRATT STREET BULKHEAD: SECTIONS 2, 3, 4, 5, AND 6, DRAWER 10, PLAN NO. 1, 1 IN. = 15 FT. AND 1/2 IN. = 1 FT., APRIL 25, 1906, DRAWING SHOWS DESIGN FOR PRATT STREET BULKHEAD BETWEEN PIERS - Baltimore Inner Harbor, Pier 5, South of Pratt Street between Market Place & Concord Street, Baltimore, Independent City, MD

  17. 2,2\\',4,4\\',5-Pentabromodiphenyl ether (BDE-99)

    Integrated Risk Information System (IRIS)

    2,2 ' , 4,4 ' , 5 - Pentabromodiphenyl ether ( BDE - 99 ) ; CASRN 60348 - 60 - 9 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 ( Hea

  18. 4.5 Doses to Patients in Diagnostics

    NASA Astrophysics Data System (ADS)

    Noßke, D.; Mattsson, S.; Johansson, L.

    This document is part of Subvolume A 'Fundamentals and Data in Radiobiology, Radiation Biophysics, Dosimetry and Medical Radiological Protection' of Volume 7 'Medical Radiological Physics' of Landolt-Börnstein - Group VIII 'Advanced Materials and Technologies'. It contains the Section '4.5 Doses to Patients in Diagnostics' of the Chapter '4 Dosimetry in Nuclear Medicine Diagnosis and Therapy' with the contents:

  19. 37 CFR 4.5 - Notice by publication.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... COMMERCE GENERAL COMPLAINTS REGARDING INVENTION PROMOTERS § 4.5 Notice by publication. If the copy of the complaint that is mailed to the invention promoter is returned undelivered, then the USPTO will primarily... in the Official Gazette and/or the Federal Register. The invention promoter will be given 30...

  20. 11 CFR 4.5 - Categories of exemptions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... individual. (b) Whenever a request is made which involves access to records described in 11 CFR 4.5(a)(7... functions, or causing substantial harm to the competitive position of the person, firm, partnership... intelligence investigation, information furnished by a confidential source; (v) Would disclose techniques...

  1. 11 CFR 4.5 - Categories of exemptions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... individual. (b) Whenever a request is made which involves access to records described in 11 CFR 4.5(a)(7... functions, or causing substantial harm to the competitive position of the person, firm, partnership... intelligence investigation, information furnished by a confidential source; (v) Would disclose techniques...

  2. 41 CFR 51-4.5 - Violations by nonprofit agencies.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Violations by nonprofit... Public Contracts COMMITTEE FOR PURCHASE FROM PEOPLE WHO ARE BLIND OR SEVERELY DISABLED 4-NONPROFIT AGENCIES § 51-4.5 Violations by nonprofit agencies. (a) Any alleged violations of these regulations by...

  3. CURRICULUM GUIDE FOR SCIENCE, GRADES 4-5-6.

    ERIC Educational Resources Information Center

    GRAHAM, KATHRYN A.; AND OTHERS

    COURSE CONTENT, ACTIVITIES, AND REFERENCE INFORMATION FOR TEACHING SCIENCE IN GRADES 4, 5, AND 6 ARE INCLUDED IN THIS VOLUME. INTRODUCTORY REMARKS RELATE TO AN APPROACH TO TEACHING SCIENCE AND THE GENERAL OBJECTIVES OF THE SCIENCE PROGRAM. THE FIVE UNITS INCLUDED FOR GRADE 4 ARE (1) INSECTS AND SPIDERS, (2) LIVING THINGS OF SIMILAR AREAS, (3) THE…

  4. Heat treatment effects on tensile properties of V-(4-5) wt.% Cr-(4-5) wt.% Ti alloys

    SciTech Connect

    Natesan, K.; Soppet, W.K.

    1997-08-01

    Effects of thermomechanical treatments on microstructures and mechanical properties are of interest for long term application of V-Cr-Ti alloys in fusion reactor systems. Influence of thermal annealing at 1050{degrees}C on stress/strain behavior, maximum engineering strength, and uniform and total elongation were evaluated. The results show that multiple annealing has minimal effect on the tensile properties of V-(4-5)Cr-(4-5)Ti alloys tested at room temperature and at 500{degrees}C.

  5. A 20 million year record of planktic foraminiferal B/Ca ratios: Systematics and uncertainties in pCO 2 reconstructions

    NASA Astrophysics Data System (ADS)

    Tripati, Aradhna K.; Roberts, Christopher D.; Eagle, Robert A.; Li, Gaojun

    2011-05-01

    We use new and published data representing a 20 million long record to discuss the systematics of interpreting planktic foraminiferal B/Ca ratios. B/Ca-based reconstructions of seawater carbonate chemistry and atmospheric pCO 2 assume that the incorporation of boron into foraminiferal tests can be empirically described by an apparent partition coefficient, KD={B/Ca}/{B(OH4-/HCO)} ( Hemming and Hanson, 1992). It has also been proposed that there is a species-specific relationship between K D and temperature ( Yu et al., 2007). As we discuss, although these relationships may be robust, there remain significant uncertainties over the controls on boron incorporation into foraminifera. It is difficult to be certain that the empirically defined correlation between temperature and K D is not simply a result of covariance of temperature and other hydrographic variables in the ocean, including carbonate system parameters. There is also some evidence that K D may be affected by solution [HCO3-]/[CO32-] ratios (i.e., pH), or by [CO32-]. In addition, the theoretical basis for the definition of K D and for a temperature control on K D is of debate. We also discuss the sensitivity of pCO 2 reconstructions to different K D-temperature calibrations and seawater B/Ca. If a K D-temperature calibration is estimated using ice core pCO 2 values between 0 and 200 ka, B/Ca ratios can be used to reasonably approximate atmospheric pCO 2 between 200 and 800 ka; however, the absolute values of pCO 2 calculated are sensitive to the choice of K D-temperature relationship. For older time periods, the absolute values of pCO 2 are also dependent on the evolution of seawater B concentrations. However, we find that over the last 20 Ma, reconstructed changes in declining pCO 2 across the Mid-Pleistocene Transition, Pliocene glacial intensification, and the Middle Miocene Climate Transition are supported by the B/Ca record even if a constant coretop K D is used, or different K D

  6. A CURRICULUM GUIDE IN FOREIGN LANGUAGE--FRENCH IN GRADES 4, 5, AND 6.

    ERIC Educational Resources Information Center

    LUTZ, STEVEN; AND OTHERS

    THIS CURRICULUM GUIDE FOR A FRENCH FLES PROGRAM, FEATURING EDUCATIONAL TELEVISION IN COMBINATION WITH CLASSROOM INSTRUCTION BY LANGUAGE SPECIALISTS, REFLECTS FIVE YEARS' EXPERIENCE WITH THE PROGRAM IN PRINCE GEORGE'S COUNTY, MARYLAND. THE PROGRAM FOR GRADES 4, 5, AND 6 DESCRIBED IN THIS GUIDE HAS BEEN EVALUATED, IMPROVED, AND IMPLEMENTED AT THE…

  7. The NIF 4.5-m nTOF Detectors

    SciTech Connect

    Moran, M J; Bond, E J; Clancy, T J; Eckart, M J; Khater, H Y; Glebov, V Y

    2012-05-07

    The first several campaigns of laser fusion experiments at the National Ignition Facility (NIF) included a family of high-sensitivity scintillator/photodetector neutron-time-of-flight (nTOF) detectors for measuring DD and DT neutron yields. The detectors provided consistent neutron yield benchmarks from below 1E9 (DD) to nearly 1E15 (DT). The detectors demonstrated DT yield measurement precisions better than 5%, but the absolute accuracy relies on cross calibration with independent measurements of absolute neutron yield. The 4.5-m nTOF data have provided a useful testbed for testing improvements in nTOF data processing, especially with respect to improving the accuracies of the detector impulse response functions. The resulting improvements in data analysis methods have produced more accurate results. In summary, results from the NIF 4.5-m nTOF detectors have provided consistent measurements of DD and DT neutron yields from laser-fusion implosions.

  8. 4.5 Meter high level waste canister study

    SciTech Connect

    Calmus, R. B.

    1997-10-01

    The Tank Waste Remediation System (TWRS) Storage and Disposal Project has established the Immobilized High-Level Waste (IBLW) Storage Sub-Project to provide the capability to store Phase I and II BLW products generated by private vendors. A design/construction project, Project W-464, was established under the Sub-Project to provide the Phase I capability. Project W-464 will retrofit the Hanford Site Canister Storage Building (CSB) to accommodate the Phase I I-ILW products. Project W-464 conceptual design is currently being performed to interim store 3.0 m-long BLW stainless steel canisters with a 0.61 in diameter, DOE is considering using a 4.5 in canister of the same diameter to reduce permanent disposal costs. This study was performed to assess the impact of replacing the 3.0 in canister with the 4.5 in canister. The summary cost and schedule impacts are described.

  9. 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.

  10. 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.

  11. 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

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

    PubMed

    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

  13. 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

  14. A 33 million-year record of Late Triassic pCO2 reflects fundamental control of the carbon-cycle by changes in continental distribution

    NASA Astrophysics Data System (ADS)

    Schaller, M. F.; Wright, J. D.; Kent, D. V.

    2012-12-01

    A ~33 My continuous record of pCO2 spanning the Late Triassic to Earliest Jurassic, based on paleosols from the eastern North American Newark rift basin, shows high pCO2 values near 4500 ± 1400 ppm (at S(z) = 3000 ± 1000 ppm) in the late Carnian, decreasing to ~2000 ± 700 ppm by the late Rhaetian, just before the eruption of the Central Atlantic Magmatic Province. These data are consistent with the model results of Godderis et al. (2008), who predict falling pCO2 through the Late Triassic as a result of the progressive increase in continental area in the tropical humid belt due to Pangea's slow northward transect. In detail, pCO2 in the Newark corresponds closely to the rate of Northward movement of the Pangean supercontinent, as determined from paleolatitude reconstructions on the Newark Basin Coring Project Cores (Kent and Tauxe, Science, 2005). These observations are more consistent with a weathering-forced driver for long-term variability in atmospheric pCO2 than with the results of simpler mass-balance models (e.g., GEOCARB, and others based on the BLAG hypothesis), wherein trends in pCO2 are forced by changes in the rate of ocean crust production and do not incorporate the effects of dynamical continental geography and lithology. Therefore, we contend that continental weathering rates, which are fundamental expressions of the composition and changing distribution of continental surface area, tightly control the 10^7-year secular changes in pCO2 observed in the Late Triassic. These findings therefore indicate that paleogeography and the rates of change in continental distributions (and lithology) could be the primary driver of Earth's climate on long timescales.

  15. Coupled carbon-isotope records from the Cenomanian of SE France: a six-million year record of mid-Cretaceous pCO2 change?

    NASA Astrophysics Data System (ADS)

    Jarvis, I.; Gröcke, D. R.; Lignum, J.; Trabucho Alexandre, J.; Kennedy, W. J.; Gale, A. S.

    2012-04-01

    The Late Cretaceous (99.6 - 65.5 Ma) provides perhaps the best example of how the Earth System may function under long-term extreme greenhouse conditions. Rapidly rising global temperatures indicate that we are heading 'back to the Cretaceous' within a few hundred years, so a better understanding of this time interval is essential. The Upper Cretaceous of the Vocontian Basin, SE France, provides excellent reference sections for studying the Cenomanian stage (99.6 - 93.6 Ma), a period of rapidly rising eustatic sea level and dramatic global warming. In the vicinity of Vergons, a >400 m thick Cenomanian succession is developed in hemipelagic and pelagic facies. Rhythmically bedded calcareous muds and marls with ~40% CaCO3 in the Upper Albian, pass up into an interbedded marl - limestone succession with rising carbonate contents through the Cenomanian, into thin marls and thick limestones with >80% CaCO3 in the Lower Turonian. Ammonites, inoceramid bivalves, planktonic foraminifera, organic walled dinoflagellate cysts (dinocysts) and calcareous nannofossils provide a basis for subdividing and dating the succession. The carbonate fraction is dominated by calcareous nannofossils; organic matter is overwhelmingly of marine origin, with palynomorphs assemblages yielding abundant dinocysts. Organic matter contents (TOC) fall from ~1% in the Upper Albian to ~ 0.08% in the Lower Turonian, but the 10 m-thick Cenomanian-Turonian boundary (CTB) interval, the Niveau Thomel, contains black shales with up to 3.5% TOC, the regional representation of Oceanic Anoxic Event 2 (OAE2). Sections (500 m) have been logged, macrofossil occurrences recorded, and samples taken every 0.5 - 1 m for microfossil, isotopic and elemental geochemistry. This paper focuses on paired carbon stable-isotope chemostratigraphic records (δ13C) in coexisting bulk carbonate (δ13Ccarb) and bulk organic matter (δ13Corg) fractions. The δ13Ccarb record from Vergons may be correlated at high-resolution to

  16. Vibration Free 4.5 K Sorption Cooler

    NASA Astrophysics Data System (ADS)

    Burger, J. F.; Holland, H. J.; Meijer, R. J.; Sirbi, A.; ter Brake, H. J. M.

    2008-03-01

    At the University of Twente, a breadboard 4.5 K sorption cooler was developed under ESA contract. It has no moving parts and, therefore, is essentially vibration-free. Moreover, it has the potential of a very long life. This cooler is a favorite option for missions such as ESA's Darwin mission, which is a future space interferometer consisting of a few free flying telescopes and a central beam combiner. Because of the optics involved, hardly any vibration can be tolerated. The cooler consists of a hydrogen stage cooling from 80 K to 14.5 K and a helium stage establishing 10 mW at 4.5 K. Both stages use micro-porous activated carbon as the adsorption material. The two cooler stages need 8 W of input power and are heat sunk at two passive radiators at temperatures of about 50 and 80 K. We developed and built a demonstrator of the helium stage. In the paper, the design, realization and tests of this demonstrator cooler are reviewed.

  17. 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

  18. 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

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

    2012-04-01

    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.

  19. 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.

  20. Million object spectrograph

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.; Ritter, Joseph M.

    2008-07-01

    A new class of astronomical telescope with a primary objective grating (POG) has been studied as an alternative to mirrors. Nineteenth century POG telescopes suffered from low resolution and ambiguity of overlapping spectra as well as background noise. The present design uses a conventional secondary spectrograph to disambiguate all objects while enjoying a very wide instantaneous field-of-view, up to 40°. The POG competes with mirrors, in part, because diffraction gratings provide the very chromatic dispersion that mirrors defeat. The resulting telescope deals effectively with long-standing restrictions on multiple object spectrographs (MOS). The combination of a POG operating in the first-order, coupled to a spectrographic astronomical telescope, isolates spectra from all objects in the free spectral range of the primary. First disclosed as a concept in year 2002, a physical proof-of-principle is now reported. The miniature laboratory model used a 50 mm plane grating primary and was able to disambiguate between objects appearing at angular resolutions of 55 arcseconds and spectral spacings of 0.15 nm. Astronomical performance is a matter of increasing instrument size. A POG configured according to our specifications has no moving parts during observations and is extensible to any length that can be held flat to tolerances approaching float glass. The resulting telescope could record over one million spectra per night of objects in a line of right ascension. The novel MOS does not require pre-imaging to start acquisition of uncharted star fields. Problems are anticipated in calibration and integration time. We propose means to ameliorate them.

  1. Multiresistant Salmonella enterica serovar 4,[5],12:i:- in Europe: a new pandemic strain?

    PubMed

    Hopkins, K L; Kirchner, M; Guerra, B; Granier, S A; Lucarelli, C; Porrero, M C; Jakubczak, A; Threlfall, E J; Mevius, D J

    2010-06-03

    A marked increase in the prevalence of S. enterica serovar 4,[5],12:i:- with resistance to ampicillin, streptomycin, sulphonamides and tetracyclines (R-type ASSuT) has been noted in food-borne infections and in pigs/pig meat in several European countries in the last ten years. One hundred and sixteen strains of S. enterica serovar 4,[5],12:i:- from humans, pigs and pig meat isolated in England and Wales, France, Germany, Italy, Poland, Spain and the Netherlands were further subtyped by phage typing, pulsed-field gel electrophoresis and multilocus variable number tandem repeat analysis to investigate the genetic relationship among strains. PCR was performed to identify the fljB flagellar gene and the genes encoding resistance to ampicillin, streptomycin, sulphonamides and tetracyclines. Class 1 and 2 integrase genes were also sought. Results indicate that genetically related serovar 4,[5],12:i:- strains of definitive phage types DT193 and DT120 with ampicillin, streptomycin, sulphonamide and tetracycline resistance encoded by blaTEM, strA-strB, sul2 and tet(B) have emerged in several European countries, with pigs the likely reservoir of infection. Control measures are urgently needed to reduce spread of infection to humans via the food chain and thereby prevent the possible pandemic spread of serovar 4,[5],12:i:- of R-type ASSuT as occurred with S. Typhimurium DT104 during the 1990s.

  2. Software for the Canadian Advanced Nanospace eXperiment-4/5 (CanX-4/-5) Mission

    NASA Astrophysics Data System (ADS)

    Leonard, Matthew Leigh

    The CanX-4 and CanX-5 mission currently under development at The University of Toronto Institute for Aerospace Studies Space Flight Laboratory UTIAS/SFL is a challenging formation flying technology demonstration. Its requirements of sub-metre control accuracy have yet to be realized with nanosatellites. Many large technical challenges must be addressed in order to ensure the success of the CanX-4/5 mission. This includes the development of software for an intersatellite communication system, integration and optimization of key formation flying algorithms onto the Payload On-Board Computer as well as the development of a Hardware-In-The-Loop simulator for full on-orbit mission simulations. This thesis will provide background knowledge of the Space Flight Laboratory and its activities, the CanX-4/5 mission, and finally highlight the authors contributions to overcoming each of these technical challenges and ensuring the success of the CanX-4 and CanX-5 mission.

  3. 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.

  4. 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.

  5. 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

  6. Stimulation of the faecal excretion of 2,4,5,2',4',5'-hexachlorobiphenyl in rats by squalane.

    PubMed

    Richter, E; Schäfer, S G; Fichtl, B

    1983-06-01

    Faecal excretion of 2,4,5,2',4',5'-hexachlorobiphenyl (6-CB) was followed for 19 weeks in rats fed a control diet, or a squalane-supplemented diet, for up to 17 weeks. In 3 d after a single oral dose of 8 mg/kg of 6-CB, 20% dose was excreted in faeces as unchanged 6-CB, which probably represents that not-absorbed. From day 4 to 133 only an additional 2-4% dose was excreted in faeces by control animals. Addition of 8% squalane to the diet 2, 6 and 15 weeks after dosing resulted in a five-fold increase of daily 6-CB excretion in faeces independent of the time of beginning the treatment. Total excretion of 6-CB in faeces from day 4 to 133 was 3.6, 6-7 and 9.3% dose after 4, 13 and 17 weeks of squalane treatment, respectively. No adverse effects of long-term squalane treatment on body-weight gain, feed efficiency and organ weights were observed. Plasma cholesterol and triglycerides were significantly lowered. Independent of the duration of treatment, the livers of rats fed the squalane-supplemented diet contained 40-50 micrograms/g squalane. Within the limits of detection no squalane could be found in lungs, kidneys, abdominal fat, spleen and blood. It is concluded that 6-CB elimination can be enhanced by oral treatment with squalane even a long time after uptake of the poison. As there was no alteration in the tissue distribution of 6-CB, the 6-CB excreted after squalane treatment probably originates from all tissues.

  7. How to Steal a Million Stars?

    NASA Astrophysics Data System (ADS)

    2006-02-01

    perturbed, the smallest stars being ripped away. "We estimate that Messier 12 lost four times as many stars as it still has", said Francesco Paresce. "That is, roughly one million stars must have been ejected into the halo of our Milky Way." The total remaining lifetime of Messier 12 is predicted to be about 4.5 billion years, i.e. about a third of its present age. This is very short compared to the typical expected globular cluster's lifetime, which is about 20 billion years. The same team of astronomers had found in 1999, another example of a globular cluster that lost a large fraction of its original content (see ESO PR 04/99). The scientists hope to discover and study many more clusters like these, since catching clusters while being disrupted should clarify the dynamics of the process that shaped the halo of our home galaxy, the Milky Way. High resolution images and their captions are available on this page. A press release on this is also issued by INAF in Italian and is available at www.inaf.it/comunicati_stampa/cs070206/Inaf-04-06.html.

  8. 4.5-kW Hall Effect Thruster Evaluated

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    2000-01-01

    As part of an Interagency Agreement with the Air Force Research Lab (AFRL), a space simulation test of a Russian SPT 140 Hall Effect Thruster was completed in September 1999 at Vacuum Facility 6 at the NASA Glenn Research Center at Lewis Field. The thruster was subjected to a three-part test sequence that included thrust and performance characterization, electromagnetic interference, and plume contamination. SPT 140 is a 4.5-kW thruster developed under a joint agreement between AFRL, Atlantic Research Corp, and Space Systems/Loral, and was manufactured by the Fakal Experimental Design Bureau of Russia. All objectives were satisfied, and the thruster performed exceptionally well during the 120-hr test program, which comprised 33 engine firings. The Glenn testing provided a critical contribution to the thruster development effort, and the large volume and high pumping speed of this vacuum facility was key to the test s success. The low background pressure (1 10 6 torr) provided a more accurate representation of space vacuum than is possible in most vacuum chambers. The facility had been upgraded recently with new cryogenic pumps and sputter shielding to support the active electric propulsion program at Glenn. The Glenn test team was responsible for all test support equipment, including the thrust stand, power supplies, data acquisition, electromagnetic interference measurement equipment, and the contamination measurement system.

  9. The Valiant 77 Million.

    ERIC Educational Resources Information Center

    Conroy, Jr., William G.

    1980-01-01

    Approximately two-thirds of the population depends on one-third of the population for survival. The valiant 77 million constitute the full-time work force in the United States. The conflict between excellence and equality weakens the development of a maximally productive work force. (JN)

  10. VLF study of low magnitude Earthquakes (4.5

    NASA Astrophysics Data System (ADS)

    Wolbang, Daniel; Biernat, Helfried; Schwingenschuh, Konrad; Eichelberger, Hans; Prattes, Gustav; Besser, Bruno; Boudjada, Mohammed; Rozhnoi, Alexander; Solovieva, Maria; Biagi, Pier Francesco; Friedrich, Martin

    2014-05-01

    In the course of the European VLF/LF radio receiver network (International Network for Frontier Research on Earthquake Precursors, INFREP), radio signals in the frequency range from 10-50 kilohertz are received, continuously recorded (temporal resolution 20 seconds) and analyzed in the Graz/Austria knot. The radio signals are generated by dedicated distributed transmitters and detected by INFREP receivers in Europe. In case the signal is crossing an earthquake preparation zone, we are in principle able to detect seismic activity if the signal to noise ratio is high enough. The requirements to detect a seismic event with the radio link methods are given by the magnitude M of the Earthquake (EQ), the EQ preparation zone and the Fresnel zone. As pointed out by Rozhnoi et al. (2009), the VLF methods are suitable for earthquakes M>5.0. Furthermore, the VLF/LF radio link gets only disturbed if it is crossing the EQ preparation zone which is described by Molchanov et al. (2008). In the frame of this project I analyze low seismicity EQs (M≤5.6) in south/eastern Europe in the time period 2011-2013. My emphasis is on two seismic events with magnitudes 5.6 and 4.8 which we are not able to adequately characterize using our single parameter VLF method. I perform a fine structure analysis of the residua of various radio links crossing the area around the particular 2 EQs. Depending on the individual paths not all radio links are crossing the EQ preparation zone directly, so a comparative study is possible. As a comparison I analyze with the same method the already good described EQ of L'Aquila/Italy in 2009 with M=6.3 and radio links which are crossing directly the EQ preparation zone. In the course of this project we try to understand in more detail why it is so difficult to detect EQs with 4.5

  11. Poloidal monochromatic pulsations in Pc4-5 range observed in the Earth magnetosphere

    NASA Astrophysics Data System (ADS)

    Belakhovsky, Vladimir

    Poloidal monochromatic pulsations in Pc4-5 range observed in the Earth magnetosphere Belakhovsky V.B.1, Pilipenko V.A.2 1 - Polar Geophysical Institute, Apatity, Russia 2 - Institute of Physics of the Earth, Moscow, Russia Monochromatic geomagnetic pulsations in the Pc4-5 frequency range in the morning sector for some events in 2007-2008 years were studied using GOES, THEMIS, and ETS spacecrafts. The satellite observations showed that these pulsations are a poloidal-type fundamental mode of Alfven field line oscillations with the dominant radial and field-aligned magnetic components. The observed pulsations are small-scale in azimuthal direction; it excited during the low geomagnetic activity and are quite similar to Pg type pulsations. Contrary to typical Pg, these pulsations practically cannot be seen on the CARISMA magnetometers. The observed magnetic pulsations were accompanied by the simultaneous pulsations in the fluxes of energetic electrons and protons, as seen by LANL satellites with a great modulation depth. A strong increase of the electron density in the magnetosphere was found before the onset of the geomagnetic pulsations. As seen by THEMIS satellites these pulsations propagate in sunward direction, i.e. in the direction of electron drift in the morning sector. We suppose that the injection of energetic electrons may be responsible for the excitation of the poloidal Pc4-5 pulsations at the morning flank of the magnetosphere, though specific excitation mechanism is still unknown.

  12. How Long Is a Piece of String? 4.5 Billion Years Perhaps!

    ERIC Educational Resources Information Center

    Russell, Terry; McGuigan, Linda

    2014-01-01

    As reported in an earlier article (Russell and McGuigan, 2014), with Nuffield Foundation support, the authors of this article have been exploring with a group of primary teachers the teaching and learning of evolution and inheritance, focusing on conceptual progression. The new National Curriculum for England requires learners to access knowledge…

  13. Phosphorylation of the rat Ins(1,4,5)P₃ receptor at T930 within the coupling domain decreases its affinity to Ins(1,4,5)P₃.

    PubMed

    Haun, Shirley; Sun, Lu; Hubrack, Satanay; Yule, David; Machaca, Khaled

    2012-01-01

    The Ins(1,4,5)P 3 receptor acts as a central hub for Ca ( 2+) signaling by integrating multiple signaling modalities into Ca ( 2+) release from intracellular stores downstream of G-protein and tyrosine kinase-coupled receptor stimulation. As such, the Ins(1,4,5)P 3 receptor plays fundamental roles in cellular physiology. The regulation of the Ins(1,4,5)P 3 receptor is complex and involves protein-protein interactions, post-translational modifications, allosteric modulation, and regulation of its sub-cellular distribution. Phosphorylation has been implicated in the sensitization of Ins(1,4,5)P 3-dependent Ca ( 2+) release observed during oocyte maturation. Here we investigate the role of phosphorylation at T-930, a residue phosphorylated specifically during meiosis. We show that a phosphomimetic mutation at T-930 of the rat Ins(1,4,5)P 3 receptor results in decreased Ins(1,4,5)P 3-dependent Ca ( 2+) release and lowers the Ins(1,4,5)P 3 binding affinity of the receptor. These data, coupled to the sensitization of Ins(1,4,5)P 3-dependent Ca ( 2+) release during meiosis, argue that phosphorylation within the coupling domain of the Ins(1,4,5)P 3 receptor acts in a combinatorial fashion to regulate Ins(1,4,5)P 3 receptor function.

  14. [Phenotypic and molecular characteristics of Salmonella enterica serotype 1,4, [5] ,12:i:--a review].

    PubMed

    Yang, Xiaojuan; Wu, Qingping; Zhang, Jumei; Guo, Weipeng

    2014-11-01

    Salmonella enterica serotype 1, 4, [5 ], 12: i:- ( Salmonella 1, 4, [5], 12: i:-), an emerging serotype antigenically related to Salmonella Typhimurium (1,4, [5], 12 : i:1,2) but lacking the second phase flagellar antigen, has been frequently detected in many countries over the last 10 years. Nowadays it seems to be one of the major serotypes responsible for human salmonellosis cases worldwide. In addition, multidrug resistance is quite common in Salmonella 1, 4, [5],12:i:-, the two major clones (labelled as Spanish and European clones) show multidrug resistance to four or more unrelated classes of antimicrobials mediated by plasmids or chromosome. Some resistance determinants including bla(TEM), bla(CTX-M(-1), aac(3)-IV, aadA2, cmlA1, sul1, sul2, dfrA12, strA-strB, tet (A) and tet (B) have been found in these multidrug resistance strains. The genomic characterization of 1,4, [5] ,12:i:- isolates suggests that this serovar is likely to gather several clones or strains that have independently emerged from S. Typhimurium, and have changed through multiple independent events involving different clonal groups. In later study, emphasis should be paid on development of rapid and precise detection methods and study of pathogenic and resistance mechanisms of Salmonella 1,4, [5] ,12:i:-.

  15. A map of dust reddening to 4.5 kpc from Pan-STARRS1

    SciTech Connect

    Schlafly, E. F.; Rix, H.-W.; Martin, N. F.; Green, G.; Finkbeiner, D. P.; Jurić, M.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E. A.; Morgan, J. S.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.; Draper, P. W.; Metcalfe, N.; Price, P. A.; Stubbs, C. W.

    2014-07-01

    We present a map of the dust reddening to 4.5 kpc derived from Pan-STARRS1 stellar photometry. The map covers almost the entire sky north of declination –30° at a resolution of 7'-14', and is based on the estimated distances and reddenings to more than 500 million stars. The technique is designed to map dust in the Galactic plane, where many other techniques are stymied by the presence of multiple dust clouds at different distances along each line of sight. This reddening-based dust map agrees closely with the Schlegel et al. (SFD) far-infrared emission-based dust map away from the Galactic plane, and the most prominent differences between the two maps stem from known limitations of SFD in the plane. We also compare the map with Planck, finding likewise good agreement in general at high latitudes. The use of optical data from Pan-STARRS1 yields reddening uncertainty as low as 25 mmag E(B – V).

  16. Molecular determinants of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) binding to transient receptor potential V1 (TRPV1) channels.

    PubMed

    Poblete, Horacio; Oyarzún, Ingrid; Olivero, Pablo; Comer, Jeffrey; Zuñiga, Matías; Sepulveda, Romina V; Báez-Nieto, David; González Leon, Carlos; González-Nilo, Fernando; Latorre, Ramón

    2015-01-23

    Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) has been recognized as an important activator of certain transient receptor potential (TRP) channels. More specifically, TRPV1 is a pain receptor activated by a wide range of stimuli. However, whether or not PI(4,5)P2 is a TRPV1 agonist remains open to debate. Utilizing a combined approach of mutagenesis and molecular modeling, we identified a PI(4,5)P2 binding site located between the TRP box and the S4-S5 linker. At this site, PI(4,5)P2 interacts with the amino acid residues Arg-575 and Arg-579 in the S4-S5 linker and with Lys-694 in the TRP box. We confirmed that PI(4,5)P2 behaves as a channel agonist and found that Arg-575, Arg-579, and Lys-694 mutations to alanine reduce PI(4,5)P2 binding affinity. Additionally, in silico mutations R575A, R579A, and K694A showed that the reduction in binding affinity results from the delocalization of PI(4,5)P2 in the binding pocket. Molecular dynamics simulations indicate that PI(4,5)P2 binding induces conformational rearrangements of the structure formed by S6 and the TRP domain, which cause an opening of the lower TRPV1 channel gate.

  17. Molecular Determinants of Phosphatidylinositol 4,5-Bisphosphate (PI(4,5)P2) Binding to Transient Receptor Potential V1 (TRPV1) Channels*

    PubMed Central

    Poblete, Horacio; Oyarzún, Ingrid; Olivero, Pablo; Comer, Jeffrey; Zuñiga, Matías; Sepulveda, Romina V.; Báez-Nieto, David; González Leon, Carlos; González-Nilo, Fernando; Latorre, Ramón

    2015-01-01

    Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) has been recognized as an important activator of certain transient receptor potential (TRP) channels. More specifically, TRPV1 is a pain receptor activated by a wide range of stimuli. However, whether or not PI(4,5)P2 is a TRPV1 agonist remains open to debate. Utilizing a combined approach of mutagenesis and molecular modeling, we identified a PI(4,5)P2 binding site located between the TRP box and the S4-S5 linker. At this site, PI(4,5)P2 interacts with the amino acid residues Arg-575 and Arg-579 in the S4-S5 linker and with Lys-694 in the TRP box. We confirmed that PI(4,5)P2 behaves as a channel agonist and found that Arg-575, Arg-579, and Lys-694 mutations to alanine reduce PI(4,5)P2 binding affinity. Additionally, in silico mutations R575A, R579A, and K694A showed that the reduction in binding affinity results from the delocalization of PI(4,5)P2 in the binding pocket. Molecular dynamics simulations indicate that PI(4,5)P2 binding induces conformational rearrangements of the structure formed by S6 and the TRP domain, which cause an opening of the lower TRPV1 channel gate. PMID:25425643

  18. Ion channel regulation by phosphoinositides analyzed with VSPs-PI(4,5)P2 affinity, phosphoinositide selectivity, and PI(4,5)P2 pool accessibility.

    PubMed

    Rjasanow, Alexandra; Leitner, Michael G; Thallmair, Veronika; Halaszovich, Christian R; Oliver, Dominik

    2015-01-01

    The activity of many proteins depends on the phosphoinositide (PI) content of the membrane. E.g., dynamic changes of the concentration of PI(4,5)P2 are cellular signals that regulate ion channels. The susceptibility of a channel to such dynamics depends on its affinity for PI(4,5)P2. Yet, measuring affinities for endogenous PIs has not been possible directly, but has relied largely on the response to soluble analogs, which may not quantitatively reflect binding to native lipids. Voltage-sensitive phosphatases (VSPs) turn over PI(4,5)P2 to PI(4)P when activated by depolarization. In combination with voltage-clamp electrophysiology VSPs are useful tools for rapid and reversible depletion of PI(4,5)P2. Because cellular PI(4,5)P2 is resynthesized rapidly, steady state PI(4,5)P2 changes with the degree of VSP activation and thus depends on membrane potential. Here we show that titration of endogenous PI(4,5)P2 with Ci-VSP allows for the quantification of relative PI(4,5)P2 affinities of ion channels. The sensitivity of inward rectifier and voltage-gated K(+) channels to Ci-VSP allowed for comparison of PI(4,5)P2 affinities within and across channel subfamilies and detected changes of affinity in mutant channels. The results also reveal that VSPs are useful only for PI effectors with high binding specificity among PI isoforms, because PI(4,5)P2 depletion occurs at constant overall PI level. Thus, Kir6.2, a channel activated by PI(4,5)P2 and PI(4)P was insensitive to VSP. Surprisingly, despite comparable PI(4,5)P2 affinity as determined by Ci-VSP, the Kv7 and Kir channel families strongly differed in their sensitivity to receptor-mediated depletion of PI(4,5)P2. While Kv7 members were highly sensitive to activation of PLC by Gq-coupled receptors, Kir channels were insensitive even when PI(4,5)P2 affinity was lowered by mutation. We hypothesize that different channels may be associated with distinct pools of PI(4,5)P2 that differ in their accessibility to PLC and VSPs.

  19. Ion channel regulation by phosphoinositides analyzed with VSPs—PI(4,5)P2 affinity, phosphoinositide selectivity, and PI(4,5)P2 pool accessibility

    PubMed Central

    Rjasanow, Alexandra; Leitner, Michael G.; Thallmair, Veronika; Halaszovich, Christian R.; Oliver, Dominik

    2015-01-01

    The activity of many proteins depends on the phosphoinositide (PI) content of the membrane. E.g., dynamic changes of the concentration of PI(4,5)P2 are cellular signals that regulate ion channels. The susceptibility of a channel to such dynamics depends on its affinity for PI(4,5)P2. Yet, measuring affinities for endogenous PIs has not been possible directly, but has relied largely on the response to soluble analogs, which may not quantitatively reflect binding to native lipids. Voltage-sensitive phosphatases (VSPs) turn over PI(4,5)P2 to PI(4)P when activated by depolarization. In combination with voltage-clamp electrophysiology VSPs are useful tools for rapid and reversible depletion of PI(4,5)P2. Because cellular PI(4,5)P2 is resynthesized rapidly, steady state PI(4,5)P2 changes with the degree of VSP activation and thus depends on membrane potential. Here we show that titration of endogenous PI(4,5)P2 with Ci-VSP allows for the quantification of relative PI(4,5)P2 affinities of ion channels. The sensitivity of inward rectifier and voltage-gated K+ channels to Ci-VSP allowed for comparison of PI(4,5)P2 affinities within and across channel subfamilies and detected changes of affinity in mutant channels. The results also reveal that VSPs are useful only for PI effectors with high binding specificity among PI isoforms, because PI(4,5)P2 depletion occurs at constant overall PI level. Thus, Kir6.2, a channel activated by PI(4,5)P2 and PI(4)P was insensitive to VSP. Surprisingly, despite comparable PI(4,5)P2 affinity as determined by Ci-VSP, the Kv7 and Kir channel families strongly differed in their sensitivity to receptor-mediated depletion of PI(4,5)P2. While Kv7 members were highly sensitive to activation of PLC by Gq-coupled receptors, Kir channels were insensitive even when PI(4,5)P2 affinity was lowered by mutation. We hypothesize that different channels may be associated with distinct pools of PI(4,5)P2 that differ in their accessibility to PLC and VSPs. PMID

  20. Synthesis of pyrimido[4,5-c]azepine- and pyrimido[4,5-c]oxepine-based γ-secretase modulators.

    PubMed

    Wu, Yong-Jin; Zhang, Yunhui; Toyn, Jeremy H; Macor, John E; Thompson, Lorin A

    2016-03-15

    This Letter describes an efficient ring-closing metathesis approach to 2-chloro-4-amino-pyrimido[4,5-c]azepines and 2-chloro-4-amino-pyrimido[4,5-c]oxepines. These chlorides were applied to the synthesis of several potent γ-secretase modulators (GSMs). PMID:26898338

  1. 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

  2. Million-Dollar Baby

    ERIC Educational Resources Information Center

    Drozdowski, Mark J.

    2007-01-01

    In this article, the author shares his experiences as a fund-raiser. He shares that fund-raising has normally two "busy seasons": (1) In December, when folks scurry to make year-end gifts in order to realize tax benefits the following April; and (2) In June 30, the end of the fiscal year. This year was a memorable year for him and his fund-raising…

  3. EVALUATION OF THE COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODEL VERSION 4.5: UNCERTAINTIES AND SENSITIVITIES IMPACTING MODEL PERFORMANCE: PART II - PARTICULATE MATTER

    EPA Science Inventory

    This paper presents an analysis of the CMAQ v4.5 model performance for particulate matter and its chemical components for the simulated year 2001. This is part two is two part series of papers that examines the model performance of CMAQ v4.5.

  4. Desulfotomaculum spp.and Methanobacterium spp. Dominate a 4-5 km Deep Fault

    SciTech Connect

    Moser, Duane P.; Gihring, Thomas M.; Brockman, Fred J.; Fredrickson, Jim K.; Balkwill, David L.; Dollhopf, M E.; Lollar, B S.; Pratt, Lisa; Boice, E.; Southam, G; Wanger, Greg; Baker, Brett; Pfiffner, S; Lin, L; Onstott, T C.

    2005-12-01

    Sulfidic, 54-60 C, 3 to 30 million year old meteoric water stably Alkaline, sulfidic, 54 to 60 C, 4 to 53 million-year-old meteoric water emanating from a borehole intersecting quartzite-hosted fractures >3.3 km beneath the surface supported a microbial community dominated by a bacterial species affiliated with Desulfotomaculum spp. and an archaeal species related to Methanobacterium spp. The geochemical homogeneity over the 650-m length of the borehole, the lack of dividing cells, and the absence of these microorganisms in mine service water support an indigenous origin for the microbial community. The coexistence of these two microorganisms is consistent with a limiting flux of inorganic carbon and SO4 2 in the presence of high pH, high concentrations of H2 and CH4, and minimal free energy for autotrophic methanogenesis. Sulfide isotopic compositions were highly enriched, consistent with microbial SO4 2 reduction under hydrologic isolation. An analogous microbial couple and similar abiogenic gas chemistry have been reported recently for hydrothermal carbonate vents of the Lost City near the Mid-Atlantic Ridge (D. S. Kelly et al., Science 307:1428-1434, 2005), suggesting that these features may be common to deep subsurface habitats (continental and marine) bearing this geochemical signature. The geochemical setting and microbial communities described here are notably different from microbial ecosystems reported for shallower continental subsurface environments.

  5. 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…

  6. Control of diverse subcellular processes by a single multi-functional lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2].

    PubMed

    Kolay, Sourav; Basu, Urbashi; Raghu, Padinjat

    2016-06-15

    Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is a multi-functional lipid that regulates several essential subcellular processes in eukaryotic cells. In addition to its well-established function as a substrate for receptor-activated signalling at the plasma membrane (PM), it is now recognized that distinct PI(4,5)P2 pools are present at other organelle membranes. However, a long-standing question that remains unresolved is the mechanism by which a single lipid species, with an invariant functional head group, delivers numerous functions without loss of fidelity. In the present review, we summarize studies that have examined the molecular processes that shape the repertoire of PI(4,5)P2 pools in diverse eukaryotes. Collectively, these studies indicate a conserved role for lipid kinase isoforms in generating functionally distinct pools of PI(4,5)P2 in diverse metazoan species. The sophistication underlying the regulation of multiple functions by PI(4,5)P2 is also shaped by mechanisms that regulate its availability to enzymes involved in its metabolism as well as molecular processes that control its diffusion at nanoscales in the PM. Collectively, these mechanisms ensure the specificity of PI(4,5)P2 mediated signalling at eukaryotic membranes.

  7. A pollen-based biome reconstruction over the last 3.562 million years in the Far East Russian Arctic - new insights into climate-vegetation relationships at the regional scale

    NASA Astrophysics Data System (ADS)

    Tarasov, P. E.; Andreev, A. A.; Anderson, P. M.; Lozhkin, A. V.; Leipe, C.; Haltia, E.; Nowaczyk, N. R.; Wennrich, V.; Brigham-Grette, J.; Melles, M.

    2013-12-01

    The recent and fossil pollen data obtained under the frame of the multi-disciplinary international El'gygytgyn Drilling Project represent a unique archive, which allows the testing of a range of pollen-based reconstruction approaches and the deciphering of changes in the regional vegetation and climate. In the current study we provide details of the biome reconstruction method applied to the late Pliocene and Quaternary pollen records from Lake El'gygytgyn. All terrestrial pollen taxa identified in the spectra from Lake El'gygytgyn were assigned to major vegetation types (biomes), which today occur near the lake and in the broader region of eastern and northern Asia and, thus, could be potentially present in this region during the past. When applied to the pollen spectra from the middle Pleistocene to present, the method suggests (1) a predominance of tundra during the Holocene, (2) a short interval during the marine isotope stage (MIS) 5.5 interglacial distinguished by cold deciduous forest, and (3) long phases of taiga dominance during MIS 31 and, particularly, MIS 11.3. These two latter interglacials seem to be some of the longest and warmest intervals in the study region within the past million years. During the late Pliocene-early Pleistocene interval (i.e., ~3.562-2.200 Ma), there is good correspondence between the millennial-scale vegetation changes documented in the Lake El'gygytgyn record and the alternation of cold and warm marine isotope stages, which reflect changes in the global ice volume and sea level. The biome reconstruction demonstrates changes in the regional vegetation from generally warmer/wetter environments of the earlier (i.e., Pliocene) interval towards colder/drier environments of the Pleistocene. The reconstruction indicates that the taxon-rich cool mixed and cool conifer forest biomes are mostly characteristic of the time prior to MIS G16, whereas the tundra biome becomes a prominent feature starting from MIS G6. These results

  8. Foreclosed: Two Million Homeless Students and Counting

    ERIC Educational Resources Information Center

    McKibben, Sarah

    2009-01-01

    This article reports that according to First Focus, a bipartisan advocacy organization for children and families, a predicted two million children will lose their homes over the next two years because of the foreclosure crisis. From an economy deep in recession, an entirely new population of homeless students has emerged. And with job losses at…

  9. Update on the Million Solar Roofs Initiative

    SciTech Connect

    Herig, C.

    1999-05-09

    The Million Solar Roofs Initiative, announced by the President in June of 1997, spans a period of twelve years and intends to increase domestic deployment of solar technologies. This paper presents an overview of the development of the initiative and significant activities to date.

  10. 3,4,5-Trichloroaniline nephrotoxicity in vitro: potential role of free radicals and renal biotransformation.

    PubMed

    Racine, Christopher; Ward, Dakota; Anestis, Dianne K; Ferguson, Travis; Preston, Deborah; Rankin, Gary O

    2014-11-13

    Chloroanilines are widely used in the manufacture of drugs, pesticides and industrial intermediates. Among the trichloroanilines, 3,4,5-trichloroaniline (TCA) is the most potent nephrotoxicant in vivo. The purpose of this study was to examine the nephrotoxic potential of TCA in vitro and to determine if renal biotransformation and/or free radicals contributed to TCA cytotoxicity using isolated renal cortical cells (IRCC) from male Fischer 344 rats as the animal model. IRCC (~4 million cells/mL; 3 mL) were incubated with TCA (0, 0.1, 0.25, 0.5 or 1.0 mM) for 60-120 min. In some experiments, IRCC were pretreated with an antioxidant or a cytochrome P450 (CYP), flavin monooxygenase (FMO), cyclooxygenase or peroxidase inhibitor prior to incubation with dimethyl sulfoxide (control) or TCA (0.5 mM) for 120 min. At 60 min, TCA did not induce cytotoxicity, but induced cytotoxicity as early as 90 min with 0.5 mM or higher TCA and at 120 min with 0.1 mM or higher TCA, as evidenced by increased lactate dehydrogenase (LDH) release. Pretreatment with the CYP inhibitor piperonyl butoxide, the cyclooxygenase inhibitor indomethacin or the peroxidase inhibitor mercaptosuccinate attenuated TCA cytotoxicity, while pretreatment with FMO inhibitors or the CYP inhibitor metyrapone had no effect on TCA nephrotoxicity. Pretreatment with an antioxidant (α-tocopherol, glutathione, ascorbate or N-acetyl-L-cysteine) also reduced or completely blocked TCA cytotoxicity. These results indicate that TCA is directly nephrotoxic to IRCC in a time and concentration dependent manner. Bioactivation of TCA to toxic metabolites by CYP, cyclooxygenase and/or peroxidase contributes to the mechanism of TCA nephrotoxicity. Lastly, free radicals play a role in TCA cytotoxicity, although the exact nature of the origin of these radicals remains to be determined.

  11. 3,4,5-Trichloroaniline Nephrotoxicity in Vitro: Potential Role of Free Radicals and Renal Biotransformation

    PubMed Central

    Racine, Christopher; Ward, Dakota; Anestis, Dianne K.; Ferguson, Travis; Preston, Deborah; Rankin, Gary O.

    2014-01-01

    Chloroanilines are widely used in the manufacture of drugs, pesticides and industrial intermediates. Among the trichloroanilines, 3,4,5-trichloroaniline (TCA) is the most potent nephrotoxicant in vivo. The purpose of this study was to examine the nephrotoxic potential of TCA in vitro and to determine if renal biotransformation and/or free radicals contributed to TCA cytotoxicity using isolated renal cortical cells (IRCC) from male Fischer 344 rats as the animal model. IRCC (~4 million cells/mL; 3 mL) were incubated with TCA (0, 0.1, 0.25, 0.5 or 1.0 mM) for 60–120 min. In some experiments, IRCC were pretreated with an antioxidant or a cytochrome P450 (CYP), flavin monooxygenase (FMO), cyclooxygenase or peroxidase inhibitor prior to incubation with dimethyl sulfoxide (control) or TCA (0.5 mM) for 120 min. At 60 min, TCA did not induce cytotoxicity, but induced cytotoxicity as early as 90 min with 0.5 mM or higher TCA and at 120 min with 0.1 mM or higher TCA, as evidenced by increased lactate dehydrogenase (LDH) release. Pretreatment with the CYP inhibitor piperonyl butoxide, the cyclooxygenase inhibitor indomethacin or the peroxidase inhibitor mercaptosuccinate attenuated TCA cytotoxicity, while pretreatment with FMO inhibitors or the CYP inhibitor metyrapone had no effect on TCA nephrotoxicity. Pretreatment with an antioxidant (α-tocopherol, glutathione, ascorbate or N-acetyl-l-cysteine) also reduced or completely blocked TCA cytotoxicity. These results indicate that TCA is directly nephrotoxic to IRCC in a time and concentration dependent manner. Bioactivation of TCA to toxic metabolites by CYP, cyclooxygenase and/or peroxidase contributes to the mechanism of TCA nephrotoxicity. Lastly, free radicals play a role in TCA cytotoxicity, although the exact nature of the origin of these radicals remains to be determined. PMID:25402648

  12. PI(4,5)P2-binding effector proteins for vesicle exocytosis

    PubMed Central

    Martin, Thomas F. J.

    2014-01-01

    PI(4,5)P2 participates directly in priming and possibly fusion steps of Ca2+-triggered vesicle exocytosis. High concentration nanodomains of PI(4,5)P2 reside on the plasma membrane of neuroendocrine cells. A subset of vesicles that co-localize with PI(4,5)P2 domains appear to undergo preferential exocytosis in stimulated cells. PI(4,5)P2 directly regulates vesicle exocytosis by recruiting and activating PI(4,5)P2-binding proteins that regulate SNARE protein function including CAPS, Munc13-1/2, synaptotagmin-1, and other C2 domain-containing proteins. These PI(4,5)P2 effector proteins are coincidence detectors that engage in multiple interactions at vesicle exocytic sites. The SNARE protein syntaxin-1 also binds to PI(4,5)P2, which promotes clustering, but an activating role for PI(4,5)P2 in syntaxin-1 function remains to be fully characterized. Similar principles underlie polarized constitutive vesicle fusion mediated in part by the PI(4,5)P2-binding subunits of the exocyst complex (Sec3, Exo70). Overall, focal vesicle exocytosis occurs at sites landmarked by PI(4,5)P2, which serves to recruit and/or activate multifunctional PI(4,5)P2-binding proteins. PMID:25280637

  13. Determination of mass changes in phosphatidylinositol 4,5-bisphosphate and evidence for agonist-stimulated metabolism of inositol 1,4,5-trisphosphate in airway smooth muscle.

    PubMed Central

    Chilvers, E R; Batty, I H; Challiss, R A; Barnes, P J; Nahorski, S R

    1991-01-01

    Stimulation of muscarinic receptors in bovine tracheal smooth muscle (BTSM) causes a sustained increase in muscle tone, but a transient increase in the second messenger Ins(1,4,5)P3. To examine whether this brief increase in Ins(1,4,5)P3 mass results from transient formation or is due to agonist-stimulation of Ins(1,4,5)P3 metabolism, we have studied the relationship between mass changes in PtdIns(4,5)P2 and Ins(1,4,5)P3 accumulation, and changes in [3H]InsP3, [3H]PtdIns, [3H]PtdInsP1 and [3H]PtdInsP2 in carbachol-stimulated myo-[3H]inositol-prelabelled BTSM slices. Carbachol (0.1 mM) caused a rapid transient increase in Ins(1,4,5)P3 concentration (basal, 12.9 +/- 0.8 pmol/mg of protein; 5 s carbachol treatment, 27.1 +/- 1.5 pmol/mg of protein), with values returning to basal levels by 30 s, but a sustained accumulation of total [3H]InsP3s, with [3H]Ins(1,3,4)P3 being the predominant isomer present at later time points. In contrast, PtdIns(4,5)P2 mass, determined by radioreceptor assay of Ins(1,4,5)P3 in desalted alkaline hydrolysates of acidified chloroform/methanol tissue extracts, declined rapidly (basal, 941 +/- 22 pmol/mg of protein; 120 s carbachol, 365 +/- 22 pmol/mg of protein; t1/2 14 s) and remained at this new steady-state level for at least 20 min in the continued presence of carbachol. Addition of 10 microM-atropine 2 min after carbachol caused a prompt return of PtdIns(4,5)P2 concentration to prestimulated values (t1/2 210 s). Ongoing resynthesis of PtdIns(4,5)P2 after carbachol stimulation was demonstrated in [3H]inositol-labelled tissue by observing a persistent increase in the specific radioactivity of [3H]PtdInsP2, shown to be exclusively [3H]PtdIns(4,5)P2, over a 10 min period. These findings strongly suggest the occurrence of persistent receptor-mediated increases in PtdIns(4,5)P2 hydrolysis and Ins(1,4,5)P3 formation which, in conjunction with the transient accumulation of Ins(1,4,5)P3 observed, provide evidence that regulation of the

  14. n-3 polyunsaturated fatty acids suppress CD4(+) T cell proliferation by altering phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] organization.

    PubMed

    Hou, Tim Y; Barhoumi, Rola; Fan, Yang-Yi; Rivera, Gonzalo M; Hannoush, Rami N; McMurray, David N; Chapkin, Robert S

    2016-01-01

    The mechanisms by which n-3 polyunsaturated fatty acids (n-3 PUFA), abundant in fish oil, exert their anti-inflammatory effects have not been rigorously defined. We have previously demonstrated that n-3 PUFA decrease the amount of phosphatidylinositol-(4,5)-bisphosphate, [PI(4,5)P2], in CD4(+) T cells, leading to suppressed actin remodeling upon activation. Since discrete pools of PI(4,5)P2 exist in the plasma membrane, we determined whether n-3 PUFA modulate spatial organization of PI(4,5)P2 relative to raft and non-raft domains. We used Förster resonance energy transfer (FRET) to demonstrate that lipid raft mesodomains in the plasma membrane of CD4(+) T cells enriched in n-3 PUFA display increased co-clustering of Lck(N10) and LAT(ΔCP), markers of lipid rafts. CD4(+) T cells enriched in n-3 PUFA also exhibited a depleted plasma membrane non-raft PI(4,5)P2 pool as detected by decreased co-clustering of Src(N15), a non-raft marker, and PH(PLC-δ), a PI(4,5)P2 reporter. Incubation with exogenous PI(4,5)P2 rescued the effects on the non-raft PI(4,5)P2 pool, and reversed the suppression of T cell proliferation in CD4(+) T cells enriched with n-3 PUFA. Furthermore, CD4(+) T cells isolated from mice fed a 4% docosahexaenoic acid (DHA)-enriched diet exhibited a decrease in the non-raft pool of PI(4,5)P2, and exogenous PI(4,5)P2 reversed the suppression of T cell proliferation. Finally, these effects were not due to changes to post-translational lipidation, since n-3 PUFA did not alter the palmitoylation status of signaling proteins. These data demonstrate that n-3 PUFA suppress T cell proliferation by altering plasma membrane topography and the spatial organization of PI(4,5)P2.

  15. 1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

    PubMed Central

    Mielgo, Antonia

    2016-01-01

    Summary Asymmetric catalysis represents a very powerful tool for the synthesis of enantiopure compounds. In this context the main focus has been directed not only to the search for new efficient chiral catalysts, but also to the development of efficient pronucleophiles. This review highlights the utility and first examples of 1H-imidazol-4(5H)-ones and thiazol-4(5H)-ones as pronucleophiles in catalytic asymmetric reactions. PMID:27340482

  16. Flood of June 4-5, 2002, in the Maquoketa River Basin, east-central Iowa

    USGS Publications Warehouse

    Eash, David A.

    2004-01-01

    Severe flooding occurred on June 4-5, 2002, in the Maquoketa River Basin in Delaware, Dubuque, Jackson, and Jones Counties, following thunderstorm activity over east-central Iowa. The rain gage at Cascade, Iowa, recorded a 14-hour rainfall of 6.0 inches at noon on June 4. Radar indications estimated as much as 8 to 10 inches of rain fell in the upper-middle part of the Maquoketa River Basin. Peak discharges on the Maquoketa River at Monticello of 47,500 cubic feet per second (recurrence interval estimated to be greater than 500 years as computed using flood-estimation equations developed by the U.S. Geological Survey), and at the Maquoketa River near Maquoketa streamflow-gaging station of 47,900 cubic feet per second (recurrence interval about 50 years), were determined for the flood. The peak discharge of the 2002 flood is nearly equal that of the 1944 flood (48,000 cubic feet per second), the largest flood on record in the Maquoketa River Basin. The 2002 flood is the largest known flood in the North Fork Maquoketa River Basin. A peak discharge of 22,600 cubic feet per second (recurrence interval about 110 years) was determined for the flood at the North Fork Maquoketa River near Fulton gaging station. Information about the basin and flood history, the 2002 thunderstorms and associated flooding, and a profile of high-water marks are presented for selected reaches along the Maquoketa and North Fork Maquoketa Rivers.

  17. NMR investigation of the binding between human profilin I and inositol 1,4,5-triphosphate, the soluble headgroup of phosphatidylinositol 4,5-bisphosphate.

    PubMed

    Richer, Sarah M; Stewart, Nichole K; Tomaszewski, John W; Stone, Martin J; Oakley, Martha G

    2008-12-23

    Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) is involved in the regulation of the actin cytoskeleton through interactions with a number of actin-binding proteins. We present here NMR titration experiments that monitor the interaction between the cytoskeletal protein profilin and inositol 1,4,5-triphosphate (IP(3)), the headgroup of PI(4,5)P(2). These experiments probe the interaction directly, at equilibrium, and with profilin in its native state. We show the binding between profilin and IP(3) can readily be observed at high concentrations, even though profilin does not bind to IP(3) under physiological conditions. Moreover, the titration data using wild-type profilin and an R88L mutant support the existence of at least three headgroup binding sites on profilin, consistent with previous experimentation with intact PI(4,5)P(2). This work suggests that various soluble inositol ligands can serve as effective probes to facilitate in vitro studies of PI-binding proteins that require membrane surfaces for high-affinity binding.

  18. Specific receptor for inositol-1,4,5-trisphosphate in permeabilized rabbit neutrophils

    SciTech Connect

    Bradford, P.G.; Spat, A.; Rubin, R.P.

    1986-03-05

    Neutrophil chemotaxis and degranulation are resultant, in part, from the mobilization of intracellular calcium by inositol-1,4,5-trisphosphate ((1,4,5)IP/sub 3/), one of the products of chemoattractant-stimulated phospholipase C activity. High specific activity (ca. 40 Ci/mmol) (/sup 32/P)(1,4,5)IP/sub 3/ was prepared from (..gamma..-/sup 32/P)ATP-labeled human erythrocyte ghosts and was used in binding assays with saponin-permeabilized rabbit peritoneal neutrophils. At 4/sup 0/C and in the presence of inhibitors of the IP/sub 3/ 5-phosphomonoesterase, (/sup 32/P)(1,4,5)IP/sub 3/ rapidly associated with a specific binding component which saturated within 60s. Nonspecific binding, taken as the residual binding in the presence of 10 ..mu..M (1,4,5)IP/sub 3/, was 15% of the total. No specific binding was detected using intact cells. The specific binding to permeable cells was reversible (t/sup 1/2/ approx. 60s) and could be inhibited in a dose-dependent manner by (1,4,5)IP/sub 3/ (EC/sub 50/ = 30 nM) and by other calcium mobilizing inositol phosphates ((2,4,5)IP/sub 3/) but not by inactive analogs ((1,4)IP/sub 2/, (4,5)IP/sub 2/, (1)IP). The dose-responses of (1,4,5)IP/sub 3/ and (2,4,5)IP/sub 3/ in inhibiting (/sup 32/P)(1,4,5)IP/sub 3/ specific binding correlated well with their abilities to release Ca/sup 2 +/ from nonmitochondrial vesicular stores in the same preparation of cells, suggesting that the authors have identified the physiological receptor for (1,4,5)IP/sub 3/.

  19. Coordination chemistry and applications of versatile 4,5-diazafluorene derivatives.

    PubMed

    Annibale, Vincent T; Song, Datong

    2016-01-01

    This perspective review will examine the coordination chemistry and applications of metal complexes of 4,5-diazafluorene derivatives. The versatile derivatives of 4,5-diazafluorene can serve multiple roles, and display a number of coordination modes. The ambidentate derivatives with multiple coordination sites can allow for the syntheses of coordination polymers, multimetallic, and macrocyclic complexes. In addition, certain 4,5-diazafluorene derivatives can serve as spectator ligands to support reactivity at the metal centre, or as reactive actor ligands engaging in atypical reactivity patterns. The applications of metal complexes of 4,5-diazafluorene derivatives in catalysis, photochemistry and photophysics, as well as in bioinorganic chemistry are also surveyed.

  20. Inositol 1,4,5-trisphosphate receptor subtypes differentially recognize regioisomers of D-myo-inositol 1,4,5-trisphosphate.

    PubMed Central

    Hirata, M; Takeuchi, H; Riley, A M; Mills, S J; Watanabe, Y; Potter, B V

    1997-01-01

    The Ins(1,4,5)P3 regioisomers, Ins(1,4,6)P3 and Ins(1,3,6)P3, which can mimic the 1,4,5-arrangement on the inositol ring of Ins(1,4,5)P3, were examined for Ca2+ release by using four types of saponin-permeabilized cell possessing various abundances of receptor subtypes, with special reference to the relation of potency to receptor subtype. Ins(1,4,6)P3 and Ins(1,3,6)P3 were weak agonists in rat basophilic leukaemic cells (RBL cells), which possess predominantly subtype II receptors, with respective potencies of 1/200 and less than 1/500 that of Ins(1,4,5)P3 [the EC50 values were 0.2, 45 and more than 100 microM for Ins(1,4,5)P3, Ins(1,4,6)P3 and Ins(1,3,6)P3 respectively]. Similar rank order potencies were also evaluated for the displacement of [3H]Ins(1,4,5)P3 bound to RBL cell membranes by these regioisomers. However, they caused Ca2+ release from GH3 rat pituitary cells possessing predominantly subtype I receptors more potently; Ins(1,4,6)P3 and Ins(1,3,6)P3 evoked release at respective concentrations of only one-third and one-twentieth that of Ins(1,4,5)P3 (the EC50 values were 0.4, 1.2 and 8 microM for Ins(1,4,5)P3, Ins(1,4,6)P3 and Ins(1,3,6)P3 respectively). In COS-1 African green-monkey kidney cells, with the relative abundances of 37% of the subtype II and of 62% of the subtype III receptor, potencies of 1/40 and approx. 1/200 for Ins(1, 4,6)P3 and Ins(1,3,6)P3 respectively were exhibited relative to Ins(1,4,5)P3 (the EC50 values were 0.4, 15 and approx. 80 microM for Ins(1,4,5)P3, Ins(1,4,6)P3 and Ins(1,3,6)P3 respectively). In HL-60 human leukaemic cells, in spite of the dominant presence of subtype I receptors (71%), similar respective potencies to those seen with COS-1 cells were exhibited (the EC50 values were 0.3, 15 and approx. 100 microM for Ins(1,4,5)P3, Ins(1,4,6)P3 and Ins(1,3,6)P3 respectively). These results indicate that these regioisomers are the first ligands that distinguish between receptor subtypes; the present observations are of

  1. The environmental impact of 4(5)-methylbenzotriazole from aircraft deicing operations

    NASA Astrophysics Data System (ADS)

    Cornell, Jeffrey Scott

    2002-01-01

    Hundreds of millions of gallons of aircraft deicer fluid (ADF) are applied to aircraft and runway surfaces annually. Recently public and regulatory attention has forced the air transport industry and military aviation community to examine the environmental impacts of aircraft deicing operations (ADOs), and to seek a balance between flight safety and environmental impact. Little data exists which is useful to evaluate the impact of ADF additives. 4(5)-methylbenzotriazole (MeBT) is used in a variety of industrial and commercial fluids to inhibit metal corrosion; it is a standard additive to most common ADF (approx. 0.5%). This MeBT component is actually a mixture of two isomers: 4-methylbenzotriazole (4-MeBT) and 5-methylbenzotriazole (5-MeBT). A significant amount of MeBT enters the natural environment through aircraft deicing operations. Research was conducted to address important data gaps impacting the ability to assess the environmental impact of MeBT and ADOs. Matrixed toxicity studies were conducted to determine the effect of different additives on ADF ecotoxicity. Aerobic liquid batch-fed microcosms were employed to investigate how MeBT affects the toxicity of wastewater containing ADF, describe how MeBT affects the aerobic biodegradation of propylene glycol (PG), and determine the biodegradability of MeBT. Field samples from contaminated areas were collected and analyzed for comparison. Cell energy production and electron transport assays were conducted to determine if MeBT was capable of disrupting oxidative phosphorylation via uncoupling, as its chemical structure would suggest. MicrotoxRTM studies indicated MeBT was toxic to test bacteria below 10 mg/L. C. dubia and P. promelas , however, were less sensitive to MeBT than bacteria but more sensitive to other ADF additives. The effect of MeBT on PG biodegradation was complex and concentration-dependent. Cell yield and PG biodegradation rates generally decreased with increasing reactor MeBT concentration

  2. Zodiacal Exoplanets in Time (ZEIT). I. A Neptune-sized Planet Orbiting an M4.5 Dwarf in the Hyades Star Cluster

    NASA Astrophysics Data System (ADS)

    Mann, Andrew W.; Gaidos, Eric; Mace, Gregory N.; Johnson, Marshall C.; Bowler, Brendan P.; LaCourse, Daryll; Jacobs, Thomas L.; Vanderburg, Andrew; Kraus, Adam L.; Kaplan, Kyle F.; Jaffe, Daniel T.

    2016-02-01

    Studying the properties of young planetary systems can shed light on how the dynamics and structure of planets evolve during their most formative years. Recent K2 observations of nearby young clusters (10-800 Myr) have facilitated the discovery of such planetary systems. Here we report the discovery of a Neptune-sized planet transiting an M4.5 dwarf (K2-25) in the Hyades cluster (650-800 Myr). The light curve shows a strong periodic signal at 1.88 days, which we attribute to spot coverage and rotation. We confirm that the planet host is a member of the Hyades by measuring the radial velocity of the system with the high-resolution near-infrared spectrograph Immersion Grating Infrared Spectrometer. This enables us to calculate a distance based on K2-25's kinematics and membership to the Hyades, which in turn provides a stellar radius and mass to ≃5%-10%, better than what is currently possible for most Kepler M dwarfs (12%-20%). We use the derived stellar density as a prior on fitting the K2 transit photometry, which provides weak constraints on eccentricity. Utilizing a combination of adaptive optics imaging and high-resolution spectra, we rule out the possibility that the signal is due to a bound or background eclipsing binary, confirming the transits’ planetary origin. K2-25b has a radius ({3.43}-0.31+0.95 R⊕) much larger than older Kepler planets with similar orbital periods (3.485 days) and host-star masses (0.29 M⊙). This suggests that close-in planets lose some of their atmospheres past the first few hundred million years. Additional transiting planets around the Hyades, Pleiades, and Praesepe clusters from K2 will help confirm whether this planet is atypical or representative of other close-in planets of similar age.

  3. 24 CFR 4.5 - Notice and documentation of assistance subject to section 102(a).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Notice and documentation of assistance subject to section 102(a). 4.5 Section 4.5 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development HUD REFORM ACT Accountability in the Provision of HUD...

  4. 44 CFR 4.5 - What is the Administrator's obligation with respect to Federal interagency coordination?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true What is the Administrator's obligation with respect to Federal interagency coordination? 4.5 Section 4.5 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL...

  5. 44 CFR 4.5 - What is the Administrator's obligation with respect to Federal interagency coordination?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false What is the Administrator's obligation with respect to Federal interagency coordination? 4.5 Section 4.5 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL...

  6. 44 CFR 4.5 - What is the Administrator's obligation with respect to Federal interagency coordination?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 false What is the Administrator's obligation with respect to Federal interagency coordination? 4.5 Section 4.5 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL...

  7. 44 CFR 4.5 - What is the Administrator's obligation with respect to Federal interagency coordination?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false What is the Administrator's obligation with respect to Federal interagency coordination? 4.5 Section 4.5 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL...

  8. 44 CFR 4.5 - What is the Administrator's obligation with respect to Federal interagency coordination?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false What is the Administrator's obligation with respect to Federal interagency coordination? 4.5 Section 4.5 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL...

  9. [Raoultella planticola, a new strain degrading 2,4,5-trichlorophenoxyacetic acid].

    PubMed

    Zharikova, N V; Markusheva, T V; Galkin, E G; Korobov, V V; Zhurenko, E Iu; Sitdikova, L R; Kolganova, T V; Kuznetsov, B B; Turova, T P

    2006-01-01

    A new strain that degrades the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) was isolated from soil, which was exposed to factors related to the petrochemical industry. According to its physiological, biochemical, cultural, and morphological traits, together with the sequence of the 16S rRNA gene, the strain was identified as Raoultella planticola 33-4ch. The strain could consume 2,4,5-T as a sole source of carbon and energy. The amount of 2,4,5-T in the culture medium decreased by 51% after five days of incubation. Raoultella planticola 33-4ch consumes 2,4,5-T to produce 4-chlorophenoxyacetic, phenoxyacetic, and 3-methyl-2,6-dioxo-4-hexenoic acids.

  10. Phenanthro[4,5-fgh]quinoxaline-Fused Subphthalocyanines: Synthesis, Structure, and Spectroscopic Characterization.

    PubMed

    Pan, Houhe; Liu, Wenbo; Wang, Chiming; Wang, Kang; Jiang, Jianzhuang

    2016-07-01

    A series of four phenanthro[4,5-fgh]quinoxaline-fused subphthalocyanine derivatives 0-3 containing zero, one, two, and three phenanthro[4,5-fgh]quinoxaline moieties, respectively, were isolated from the mixed cyclotrimerization reaction of 2,9-di-tert-butylphenanthro[4,5-fgh]quinoxaline-5,6-dicarbonitrile with 4,5-bis(2,6-diisopropylphenoxy)phthalonitrile and characterized by a series of spectroscopic methods including MALDI-TOF mass, (1) H NMR, electronic absorption, magnetic circular dichroism (MCD), and fluorescence spectroscopy. The molecular structures for the compounds 0 and 2 were clearly revealed on the basis of single-crystal X-ray diffraction analysis. Their electrochemical properties were also studied by cyclic voltammetry. In particular, theoretical calculations in combination with the electronic absorption and electrochemical analyses revealed the significant influence of the fused-phenanthro[4,5-fgh]quinoxaline units on the electronic structures.

  11. Natural selection for 2,4,5-trichlorophenoxyacetic acid mineralizing bacteria in agent orange contaminated soil.

    PubMed

    Rice, J F; Menn, F M; Hay, A G; Sanseverino, J; Sayler, G S

    2005-12-01

    Agent Orange contaminated soils were utilized in direct enrichment culture studies to isolate 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 2,4-dichlorophenoxyacetic acid (2,4-D) mineralizing bacteria. Two bacterial cultures able to grow at the expense of 2,4,5-T and/or 2,4-D were isolated. The 2,4,5-T degrading culture was a mixed culture containing two bacteria, Burkholderia species strain JR7B2 and Burkholderia species strain JR7B3. JR7B3 was able to metabolize 2,4,5-T as the sole source of carbon and energy, and demonstrated the ability to affect metabolism of 2,4-D to a lesser degree. Strain JR7B3 was able to mineralize 2,4,5-T in pure culture and utilized 2,4,5-T in the presence of 0.01% yeast extract. Subsequent characterization of the 2,4-D degrading culture showed that one bacterium, Burkholderia species strain JRB1, was able to utilize 2,4-D as a sole carbon and energy source in pure culture. Polymerase chain reaction (PCR) experiments utilizing known genetic sequences from other 2,4-D and 2,4,5-T degrading bacteria demonstrated that these organisms contain gene sequences similar to tfdA, B, C, E, and R (Strain JRB1) and the tftA, C, and E genes (Strain JR7B3). Expression analysis confirmed that tftA, C, and E and tfdA, B, and C were transcribed during 2,4,5-T and 2,4-D dependent growth, respectively. The results indicate a strong selective pressure for 2,4,5-T utilizing strains under field condition. PMID:15865343

  12. Natural selection for 2,4,5-trichlorophenoxyacetic acid mineralizing bacteria in agent orange contaminated soil.

    PubMed

    Rice, J F; Menn, F M; Hay, A G; Sanseverino, J; Sayler, G S

    2005-12-01

    Agent Orange contaminated soils were utilized in direct enrichment culture studies to isolate 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 2,4-dichlorophenoxyacetic acid (2,4-D) mineralizing bacteria. Two bacterial cultures able to grow at the expense of 2,4,5-T and/or 2,4-D were isolated. The 2,4,5-T degrading culture was a mixed culture containing two bacteria, Burkholderia species strain JR7B2 and Burkholderia species strain JR7B3. JR7B3 was able to metabolize 2,4,5-T as the sole source of carbon and energy, and demonstrated the ability to affect metabolism of 2,4-D to a lesser degree. Strain JR7B3 was able to mineralize 2,4,5-T in pure culture and utilized 2,4,5-T in the presence of 0.01% yeast extract. Subsequent characterization of the 2,4-D degrading culture showed that one bacterium, Burkholderia species strain JRB1, was able to utilize 2,4-D as a sole carbon and energy source in pure culture. Polymerase chain reaction (PCR) experiments utilizing known genetic sequences from other 2,4-D and 2,4,5-T degrading bacteria demonstrated that these organisms contain gene sequences similar to tfdA, B, C, E, and R (Strain JRB1) and the tftA, C, and E genes (Strain JR7B3). Expression analysis confirmed that tftA, C, and E and tfdA, B, and C were transcribed during 2,4,5-T and 2,4-D dependent growth, respectively. The results indicate a strong selective pressure for 2,4,5-T utilizing strains under field condition.

  13. 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)

  14. CRAC channel is inhibited by neomycin in a Ptdlns(4,5)P2-independent manner.

    PubMed

    Huang, Kun; Wang, Xuemei; Liu, Yanjun; Zhao, Yi

    2015-03-01

    Depletion of intracellular Ca(2+) stores evokes store-operated Ca(2+) entry through the Ca(2+) release-activated Ca(2+) (CRAC) channels. In this study, we found that the store-operated Ca(2+) entry was inhibited by neomycin, an aminoglycoside that strongly binds phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). Patch clamp recordings revealed that neomycin blocked the CRAC currents reconstituted by co-expression of Orai1 and Stim1 in HEK293 cells. Using a rapamycin-inducible PtdIns(4,5)P2-specific phosphatase (Inp54p) system to manipulate the PtdIns(4,5)P2 in the plasma membrane, we found that the CRAC current was not altered by PtdIns(4,5)P2 depletion. This result suggests that PtdIns(4,5)P2 is not required for CRAC channel activity, and thereby, neomycin inhibits CRAC channels in a manner that is independent of neomycin-PtdIns(4,5)P2 binding.

  15. Phosphatidylinositol 4,5-bisphosphate rescues TRPM4 channels from desensitization.

    PubMed

    Zhang, Zheng; Okawa, Haruhisa; Wang, Yuanyuan; Liman, Emily R

    2005-11-25

    TRPM4 is a Ca(2+)-activated nonselective cation channel that regulates membrane potential in response to intracellular Ca(2+) signaling. In lymphocytes it plays an essential role in shaping the pattern of intracellular Ca(2+) oscillations that lead to cytokine secretion. To better understand its role in this and other physiological processes, we investigated mechanisms by which TRPM4 is regulated. TRPM4 was expressed in ChoK1 cells, and currents were measured in excised patches. Under these conditions, TRPM4 currents were activated by micromolar concentrations of cytoplasmic Ca(2+) and progressively desensitized. Here we show that desensitization can be explained by a loss of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) from the channels. Poly-l-lysine, a PI(4,5)P(2) scavenger, caused rapid desensitization, whereas MgATP, at concentrations that activate lipid kinases, promoted recovery of TRPM4 currents. Application of exogenous PI(4,5)P(2) to the intracellular surface of the patch restored the properties of TRPM4 currents. Our results suggest that PI(4,5)P(2) acts to uncouple channel opening from changes in the transmembrane potential, allowing current activation at physiological voltages. These data argue that hydrolysis of PI(4,5)P(2) underlies desensitization of TRPM4 and support the idea that PI(4,5)P(2) is a general regulator for the gating of TRPM ion channels. PMID:16186107

  16. Chemical accessibility of the 4.5S RNA in spinach chloroplast ribosomes.

    PubMed Central

    Kumagai, I; Bartsch, M; Subramanian, A R; Erdmann, V A

    1983-01-01

    We have examined the accessibility to diethylpyrocarbonate of spinach chloroplast 4.5S ribosomal RNA when free and when it is part of the ribosomal structure. The modifications in free 4.5S RNA were found mostly in single-stranded regions of the secondary structure model proposed in our previous paper (Kumagai, I. et al. (1982) J.B.C. 257, 12924-28): adenines at positions 17, 19, 33, 36, 54, 55, 60, 64, 68, 72, 77, 86 and 87 were identified as the reactive residues. On the other hand, in 4.5S RNA in 70S ribosomes or 50S subunits, adenine 33 was exclusively modified, and its reactivity was much higher than in free 4.5S RNA. This highly accessible A33 of spinach 4.5S RNA is located within a characteristic seven nucleotide sequence, which is found in the 4.5S rRNAs from spinach, tobacco and a fern but deleted in 4.5S RNAs from maize and wheat. Images PMID:6828382

  17. Mouse nucleolin binds to 4.5S RNAH, a small noncoding RNA

    SciTech Connect

    Hirose, Yutaka Harada, Fumio

    2008-01-04

    4.5S RNAH is a rodent-specific small noncoding RNA that exhibits extensive homology to the B1 short interspersed element. Although 4.5S RNAH is known to associate with cellular poly(A)-terminated RNAs and retroviral genomic RNAs, its function remains unclear. In this study, we analyzed 4.5S RNAH-binding proteins in mouse nuclear extracts using gel mobility shift and RNA-protein UV cross-linking assays. We found that at least nine distinct polypeptides (p170, p110, p93, p70, p48, p40, p34, p20, and p16.5) specifically interacted with 4.5S RNAHin vitro. Using anti-La antibody, p48 was identified as mouse La protein. To identify the other 4.5S RNAH-binding proteins, we performed expression cloning from a mouse cDNA library and obtained cDNA clones derived from nucleolin mRNA. We identified p110 as nucleolin using nucleolin-specific antibodies. UV cross-linking analysis using various deletion mutants of nucleolin indicated that the third of four tandem RNA recognition motifs is a major determinant for 4.5S RNAH recognition. Immunoprecipitation of nucleolin from the subcellular fractions of mouse cell extracts revealed that a portion of the endogenous 4.5S RNAH was associated with nucleolin and that this complex was located in both the nucleoplasm and nucleolus.

  18. Smooth muscle length-dependent PI(4,5)P2 synthesis and paxillin tyrosine phosphorylation.

    PubMed

    Sul, D; Baron, C B; Broome, R; Coburn, R F

    2001-07-01

    We studied effects of increasing the length of porcine trachealis muscle on 5.5 microM carbachol (CCh)-evoked phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] synthesis and other parameters of phosphatidylinositol (PI) turnover. PI(4,5)P2 resynthesis rates in muscle held at 1.0 optimal length (L(o)), measured over the first 6 min of CCh stimulation, were 140 +/- 12 and 227 +/- 14% of values found in muscle held at 0.5 L(o) and in free-floating muscle, respectively. Time-dependent changes in cellular masses of PI(4,5)P2, PI, and phosphatidic acid, and PI resynthesis rates, were also altered by the muscle length at which contraction occurred. In free-floating muscle, CCh did not evoke increases in tyrosine-phosphorylated paxillin (PTyr-paxillin), an index of beta1-integrin signaling; however, there were progressive increases in PTyr-paxillin in muscle held at 0.5 and 1.0 L(o) during contraction, which correlated with increases in PI(4,5)P2 synthesis rates. These data indicate that PI(4,5)P2 synthesis rates and other parameters of CCh-stimulated inositol phospholipid turnover are muscle length-dependent and provide evidence that supports the hypothesis that length-dependent beta1-integrin signals may exert control on CCh-activated PI(4,5)P2 synthesis.

  19. Is inositol (1,3,4,5)-tetrakisphosphate a new second messenger

    SciTech Connect

    Hansen, C.A.; Williamson, J.R.

    1986-05-01

    Hormone-stimulated hydrolysis of inositol (Ins) lipids results in the rapid formation of Ins(1,4,5)P/sub 3/, the second messenger for intracellular Ca/sup 2 +/ mobilization. Recently, a more polar inositol phosphate, Ins(1,3,4,5)P/sub 4/ as well as its probable hydrolysis product Ins(1,3,4)P/sub 3/ have been reported to accumulate in carbachol-stimulated brain slices. Vasopressin addition to hepatocytes prelabeled with (/sup 3/H)-Ins also showed a rapid increase of Ins(1,3,4,5)P/sub 4/, which was similar to that of Ins(1,4,5)P/sub 3/, while the accumulation of Ins(1,3,4)P/sub 3/ was slower. In order to examine whether Ins(1,3,4,5)P/sub 4/ has any functional effects on Ca/sup 2 +/ homeostasis, it was synthesized enzymatically from (/sup 3/H)-Ins(1,4,5)P/sub 3/ using a partially purified phosphoinositol kinase activity from rat brain cortex. (/sup 3/H)-labeled inositol phosphates were separated by anion exchange chromatography and analyzed by HPLC using ammonium formate/phosphoric acid gradient elution. Preliminary experiments indicate that Ins(1,3,4,5)P/sub 4/ up to 10 ..mu..M does not release Ca/sup 2 +/ from vesicular pools in saponin-permeabilized hepatocytes. It has a slight inhibitory effect on Ins(1,4,5)P/sub 3/-induced Ca/sup 2 +/ release. The effect of Ins(1,3,4,5)P/sub 4/ on plasma membrane Ca/sup 2 +/ fluxes are presently being investigated.

  20. Molecular target sizes of inositol 1,4,5-trisphosphate receptors in liver and cerebellum.

    PubMed Central

    Nunn, D L; Potter, B V; Taylor, C W

    1990-01-01

    Ins(1,4,5)P3 is the intracellular messenger that mediates the effects of many cell-surface receptors on intracellular Ca2+ stores. Although radioligand-binding studies have identified high-affinity Ins(1,4,5)P3-binding sites in many tissues, these have not yet been convincingly shown to be the receptors that mediate Ca2+ mobilization, nor is it clear whether there are differences in these binding sites between tissues. Here we report that Ins(1,4,5)P3 binds to a single class of high-affinity sites in both permeabilized hepatocytes (KD = 7.8 +/- 1.1 nM) and cerebellar membranes (KD = 6.5 +/- 2.4 nM), and provide evidence that these are unlikely to reflect binding to either of the enzymes known to metabolize Ins(1,4,5)P3. Furthermore, the rank order of potency of synthetic inositol phosphate analogues in displacing specifically bound Ins(1,4,5)P3 is the same as their rank order of potency in stimulating mobilization of intracellular Ca2+ stores, suggesting that the Ins(1,4,5)P3-binding site may be the physiological receptor. Radiation inactivation of the Ins(1,4,5)P3-binding sites of liver and cerebellum reveals that they have similar molecular target sizes: 257 +/- 36 kDa in liver and 258 +/- 20 kDa in cerebellum. We conclude that an Ins(1,4,5)P3-binding protein with a molecular target size of about 260 kDa is probably the receptor that mediates Ca2+ mobilization in hepatocytes, and our limited data provide no evidence to distinguish this from the cerebellar Ins(1,4,5)P3-binding protein. PMID:2154187

  1. Energetic Trinitro- and Fluorodinitroethyl Ethers of 1,2,4,5-Tetrazines.

    PubMed

    Chavez, David E; Parrish, Damon A; Mitchell, Lauren

    2016-07-18

    Several new energetic ethyl ethers of 1,2,4,5-tetrazine have been synthesized. These molecules display good thermal stability, good oxygen balance, and high densities. Included in these studies are a 2,2,2-trinitroethoxy 1,2,4,5-tetrazine and two fluorodinitroethoxy 1,2,4,5-tetrazines. One of these compounds was converted into the di-N-oxide derivative. The sensitivity of these materials towards destructive stimuli was determined, and overall the materials show promising energetic performance properties.

  2. 2,4,5,2',4',5'-Hexachlorobiphenyl-lipoprotein (LDL, HDL, VLDL) interaction and induced lipidosis in cultured skin fibroblasts

    SciTech Connect

    Kling, D.; Becker, M.M.; Kruth, H.S.; Gamble, W.

    1984-06-01

    2,4,5,2',4',5'-Hexachlorobiphenyl (HCB) induced cytoplasmic inclusions and lipidosis in normal (AG1437) and hypercholesterolemic (GM488) human skin fibroblasts. Quantitative and qualitative microscopic fluorescence analysis showed that the cytoplasmic inclusions are formed as early as 3 hr after treatment with HCB. The inclusions contain lipids but no detectable nonesterified cholesterol or cholesteryl ester. High density lipoproteins (HDL), low density lipoproteins (LDL), and very low density lipoproteins (VLDL) facilitate the apparent uptake of HCB by skin fibroblasts. HDL and LDL appeared to reverse the induction of cytoplasmic inclusions and lipidosis when cells were pretreated with HCB, the HCB was removed from media, and the cells were incubated with LDL or HDL. The results suggest that lipoproteins participate in the uptake and egress of HCB from skin fibroblasts.

  3. Processable, high temperature polymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and bis-dienes

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.

    1988-01-01

    1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene reacts with various anthracene end-capped polyimide oligomers to form Diels-Alder cycloaddition copolymers. The polymers are soluble in common organic solvents, and have molecular weights of approximately 21,000 to 32,000. These resins exhibit lower weight loss in air than in nitrogen. This is suggested to be due to dehydration (loss of water ranges from 2 to 5 percent) at temperatures of 390 to 400 C to give thermooxidatively stable pentiptycene units along the polymer backbone. Because of their high softening points and good thermooxidative stability, the polymers have potential as processable, matrix resins for high temperature composite applications.

  4. Addition polymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and Bis-dienes: Processable resins for high temperature application

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.

    1987-01-01

    1,4,5,8-Tetrahydro-1,4;5,8-diepoxyanthracene reacts with various anthracene endcapped polyimide oligomers to form Diels-Alder cycloaddition copolymers. The polymers are soluble in common organic solvents, and have molecular weights of approximately 21,000 to 32,000. Interestingly, these resins appear to be more stable in air then in nitrogen. This is shown to be due to a unique dehydration (loss of water ranges from 2 to 5 percent) at temperatures of 390 to 400 C to give thermo-oxidatively stable pentiptycene units along the polymer backbone. Because of their high softening points and good thermo-oxidative stability, the polymers have potential as processible, matrix resins for high temperature composite applications.

  5. c-Fos-activated synthesis of nuclear phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P₂] promotes global transcriptional changes.

    PubMed

    Ferrero, Gabriel O; Renner, Marianne L; Gil, Germán A; Rodríguez-Berdini, Lucia; Caputto, Beatriz L

    2014-08-01

    c-Fos is a well-recognized member of the AP-1 (activator protein-1) family of transcription factors. In addition to this canonical activity, we previously showed that cytoplasmic c-Fos activates phospholipid synthesis through a mechanism independent of its genomic AP-1 activity. c-Fos associates with particular enzymes of the lipid synthesis pathway at the endoplasmic reticulum and increases the Vmax of the reactions without modifying the Km values. This lipid synthesis activation is associated with events of differentiation and proliferation that require high rates of membrane biogenesis. Since lipid synthesis also occurs in the nucleus, and different phospholipids have been assigned transcription regulatory functions, in the present study we examine if c-Fos also acts as a regulator of phospholipid synthesis in the nucleus. Furthermore, we examine if c-Fos modulates transcription through its phospholipid synthesis activator capacity. We show that nuclear-localized c-Fos associates with and activates PI4P5K (phosphatidylinositol-4-monophosphate 5-kinase), but not with PI4KIIIβ (type IIIβ phosphatidylinositol 4-kinase) thus promoting PtdIns(4,5)P₂ (phosphatidylinositol 4,5-bisphosphate) formation, which, in turn, promotes transcriptional changes. We propose c-Fos as a key regulator of nuclear PtdIns(4,5)P₂ synthesis in response to growth signals that results in c-Fos-dependent transcriptional changes promoted by the newly synthesized lipids.

  6. 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.

  7. Calcium Promotes the Formation of Syntaxin 1 Mesoscale Domains through Phosphatidylinositol 4,5-Bisphosphate*

    PubMed Central

    Platen, Mitja; Junius, Meike; Diederichsen, Ulf; Schaap, Iwan A. T.; Honigmann, Alf; Jahn, Reinhard; van den Bogaart, Geert

    2016-01-01

    Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is a minor component of total plasma membrane lipids, but it has a substantial role in the regulation of many cellular functions, including exo- and endocytosis. Recently, it was shown that PI(4,5)P2 and syntaxin 1, a SNARE protein that catalyzes regulated exocytosis, form domains in the plasma membrane that constitute recognition sites for vesicle docking. Also, calcium was shown to promote syntaxin 1 clustering in the plasma membrane, but the molecular mechanism was unknown. Here, using a combination of superresolution stimulated emission depletion microscopy, FRET, and atomic force microscopy, we show that Ca2+ acts as a charge bridge that specifically and reversibly connects multiple syntaxin 1/PI(4,5)P2 complexes into larger mesoscale domains. This transient reorganization of the plasma membrane by physiological Ca2+ concentrations is likely to be important for Ca2+-regulated secretion. PMID:26884341

  8. Synthesis and structure-activity relationships of 2-alkylidenethiazolidine-4,5-diones as antibiotic agents.

    PubMed

    Albrecht, Uwe; Gördes, Dirk; Schmidt, Enrico; Thurow, Kerstin; Lalk, Michael; Langer, Peter

    2005-07-15

    2-Alkylidenethiazolidine-4,5-diones were prepared by novel one-pot cyclizations of arylacetonitriles with isothiocyanates and ethyl 2-chloro-2-oxoacetate. The products show antibiotic activity against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus.

  9. Signal-dependent Hydrolysis of Phosphatidylinositol 4,5-Bisphosphate without Activation of Phospholipase C

    PubMed Central

    Lev, Shaya; Katz, Ben; Tzarfaty, Vered; Minke, Baruch

    2012-01-01

    In Drosophila, a phospholipase C (PLC)-mediated signaling cascade, couples photo-excitation of rhodopsin to the opening of the transient receptor potential (TRP) and TRP-like (TRPL) channels. A lipid product of PLC, diacylglycerol (DAG), and its metabolites, polyunsaturated fatty acids (PUFAs) may function as second messengers of channel activation. However, how can one separate between the increase in putative second messengers, change in pH, and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) depletion when exploring the TRPL gating mechanism? To answer this question we co-expressed the TRPL channels together with the muscarinic (M1) receptor, enabling the openings of TRPL channels via G-protein activation of PLC. To dissect PLC activation of TRPL into its molecular components, we used a powerful method that reduced plasma membrane-associated PI(4,5)P2 in HEK cells within seconds without activating PLC. Upon the addition of a dimerizing drug, PI(4,5)P2 was selectively hydrolyzed in the cell membrane without producing DAG, inositol trisphosphate, or calcium signals. We show that PI(4,5)P2 is not an inhibitor of TRPL channel activation. PI(4,5)P2 hydrolysis combined with either acidification or application of DAG analogs failed to activate the channels, whereas PUFA did activate the channels. Moreover, a reduction in PI(4,5)P2 levels or inhibition of DAG lipase during PLC activity suppressed the PLC-activated TRPL current. This suggests that PI(4,5)P2 is a crucial substrate for PLC-mediated activation of the channels, whereas PUFA may function as the channel activator. Together, this study defines a narrow range of possible mechanisms for TRPL gating. PMID:22065576

  10. Phosphatidylinositol 4,5-bisphosphate-dependent regulation of the output in lobster olfactory receptor neurons.

    PubMed

    Bobkov, Yuriy V; Pezier, Adeline; Corey, Elizabeth A; Ache, Barry W

    2010-05-01

    Transient receptor potential (TRP) channels often play a role in sensory transduction, including chemosensory transduction. TRP channels, a common downstream target of phosphoinositide (PI) signaling, can be modulated by exogenous phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] and/or diacylglycerol (DAG). Lobster olfactory receptor neurons (ORNs) express a TRP-related, non-selective, calcium/magnesium-permeable, sodium/calcium-gated cation (SGC) channel. Here we report that PIs regulate the function of the calcium-activated form of the lobster channel. Sequestering of endogenous PI(4,5)P2, either with an anti-PI(4,5)P2 antibody or by electrostatic screening with polyvalent cations, blocks the channel. Exogenous PI(3,4,5)P3 activates the channel independently of intracellular sodium and/or calcium. Exogenous non-hydrolysable DAG analogs fail to change the gating parameters of the channel, suggesting the channel is insensitive to DAG. Electrophysiological recording from lobster ORNs in situ using a panel of pharmacological tools targeting the key components of both PI and DAG metabolism (phospholipase C, phosphoinositide 4-kinase and DAG kinase) extend these findings to the intact ORN. PI(4,5)P2 depletion suppresses both the odorant-evoked discharge and whole-cell current of the cells, and does so possibly independently of DAG production. Collectively, our results argue that PIs can regulate output in lobster ORNs, at least in part through their action on the lobster SGC channel.

  11. The nitration pattern of energetic 3,6-diamino-1,2,4,5-tetrazine derivatives containing azole functional groups.

    PubMed

    Aizikovich, A; Shlomovich, A; Cohen, A; Gozin, M

    2015-08-21

    One of the successful strategies for the design of promising new energetic materials is the incorporation of both fuel and oxidizer moieties into the same molecule. Therefore, during recent years, synthesis of various nitro-azole derivatives, as compounds with a more balanced oxygen content, has become very popular. In the framework of this effort, we studied nitration of N(3),N(6)-bis(1H-tetrazol-5-yl)-1,2,4,5-tetrazine-3,6-diamine (BTATz; ) and its alkylated derivative N(3),N(6)-bis(2-methyl-2H-tetrazol-5-yl)-1,2,4,5-tetrazine-3,6-diamine , using a (15)N-labeled nitration agent and monitoring and analyzing products of these reactions by (15)N NMR. It was seen that the nitration of both compounds takes place only on the exocyclic ("bridging") secondary amine groups. Possible tetranitro derivative isomers N,N'-(1,2,4,5-tetrazine-3,6-diyl)bis(N-(1-nitro-1H-tetrazol-5-yl)-nitramide) and N,N'-(1,2,4,5-tetrazine-3,6-diyl)bis(N-(2-nitro-2H-tetrazol-5-yl)nitramide) , both of which have OB = 0% and calculated VODs of 9790 and 9903 m s(-1), respectively, could not be observed in the reaction mixtures, during the in situ(15)N NMR monitoring of nitration of , using (15)N-labeled nitrating agents. Following a similar strategy, a new analog of BTATz - N(3),N(6)-Bis(1H-1,2,4-triazol-5-yl)-1,2,4,5-tetrazine-3,6-diamine was obtained and its nitration was studied. The reaction of with a HNO3-Ac2O nitration mixture resulted in the formation of a new N(3),N(6)-bis(3-nitro-1H-1,2,4-triazol-5-yl)-1,2,4,5-tetrazine-3,6-diamine derivative in a moderate yield. Structures and properties of (in the form of its perchlorate salt, ) and were measured by FTIR, multinuclear NMR, MS, DSC and X-ray crystallography. It is important to note that compound exhibits exothermic decomposition at 302 °C (DSC) and >353 N (sensitivity to friction), making it a highly-promising thermally-insensitive energetic material for further development.

  12. Analysis and risk assessment of 4(5)-methylimidazole in brown colored foods and beverages.

    PubMed

    Lee, Sumin; Lee, Kwang-Geun

    2016-01-01

    In this study, the 4(5)-methylimidazole (4(5)-MI) levels in various 144 brown coloured foods and beverages were determined. The brown coloured foods and beverages were 62 processed sauces, 40 coffee, 9 caramel syrups, 18 red ginseng juice and 15 Japanese apricot fruit juice. The amount of 4(5)-MI in brewed coffee (1821.3 ng/g) was the highest level among the samples. The 4(5)-MI concentration in processed sauce (47.6 ng/g) was the lowest level among the samples. The levels of 4(5)-MI in various samples were found as follows: 47.6-1748.5 ng/g in processed sauces, 64.1-1821.3 ng/g in commercial coffee, 115.5-491.9 ng/g in caramel syrups, 91.0-854.1 ng/g in red ginseng juice and 137.6-587.4 ng/g in Japanese apricot fruit juice. Based on the 4(5)-MI levels, the estimated daily intake (EDI) and chronic daily intake (CDI) were calculated. EDI and CDI of red ginseng juice was the highest among all samples, and they were 1618.6 and 1256.8 ng/kg bw/day, respectively.

  13. Analysis and risk assessment of 4(5)-methylimidazole in brown colored foods and beverages.

    PubMed

    Lee, Sumin; Lee, Kwang-Geun

    2016-01-01

    In this study, the 4(5)-methylimidazole (4(5)-MI) levels in various 144 brown coloured foods and beverages were determined. The brown coloured foods and beverages were 62 processed sauces, 40 coffee, 9 caramel syrups, 18 red ginseng juice and 15 Japanese apricot fruit juice. The amount of 4(5)-MI in brewed coffee (1821.3 ng/g) was the highest level among the samples. The 4(5)-MI concentration in processed sauce (47.6 ng/g) was the lowest level among the samples. The levels of 4(5)-MI in various samples were found as follows: 47.6-1748.5 ng/g in processed sauces, 64.1-1821.3 ng/g in commercial coffee, 115.5-491.9 ng/g in caramel syrups, 91.0-854.1 ng/g in red ginseng juice and 137.6-587.4 ng/g in Japanese apricot fruit juice. Based on the 4(5)-MI levels, the estimated daily intake (EDI) and chronic daily intake (CDI) were calculated. EDI and CDI of red ginseng juice was the highest among all samples, and they were 1618.6 and 1256.8 ng/kg bw/day, respectively. PMID:26653824

  14. NT4/5 mutant mice have deficiency in gustatory papillae and taste bud formation.

    PubMed

    Liebl, D J; Mbiene, J P; Parada, L F

    1999-09-15

    Neurotrophins are key determinants for controlling the survival of peripheral neurons during development. Brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT4/5) exert their action through a common trkB receptor but independently support gustatory sensory neurons. To assess the role of NT4/5 during development, we examined the postnatal development and maintenance of fungiform taste buds in mice carrying a deletion of NT4/5. The absence of NT4/5 results in embryonic deficits in gustatory innervation and a reduced number of fungiform papillae at birth. No degenerative deficits of fungiform papillae were observed for the first 3 weeks of postnatal development. However, these remaining fungiform papillae were smaller in appearance and many did not contain taste pores. By postnatal day 60, there was 63% decrease in the number of fungiform papillae, and remaining papillae were smaller in size or modified into filiform-like spines. These papillae had either no taste bud or a taste bud with a reduced number of taste cells compared to controls. These findings demonstrate that the NT4/5 gene functions in the maintenance of fungiform gustatory papillae and raises the possibility for an earlier role in development. PMID:10479455

  15. BIOTRANSFORMATION OF TRANS-4,5-DIHYDROXY-4,5-DIHYDROBENZO[A]PYRENE TO BENZO[A]PYRENE-BIS-DIOLS AND DNA ADDUCTS BY INDUCED RAT LIVER MICROSOMES

    EPA Science Inventory

    The biotransformation of (+)-trans-4,5-dihydroxy-4,5-dihydrobenzo[a]pyrene trans-B[a]P-4,5-diol), the K-region dihydrodiol of B[a]P, by B-naphthoflavone (BNF)-induced rat liver microsomes was studied. Trans-B[a]P-4,5-diol was metabolized to six major products as characterized by...

  16. Mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) and mixtures of 2,4-D and 2,4,5-trichlorophenoxyacetic acid by Phanerochaete chrysosporium

    SciTech Connect

    Yadav, J.S.; Reddy, C.A. )

    1993-09-01

    2,4-dichloropheonxyacetic Acid (2,4-D) is one of the most commonly used phenoxyalkanoic herbicides for selective control of weeds and for defoliation. Since these toxic chemical are manufactured and used each year in massive quantities, effective handling of their production wastes and the contaminated environment is needed. A number of bacterial general are known to degrade 2,4-D, but no naturally occuring bacterium is know to be capable of mineralizing 2,4,5-trichlorophenoxyacetic acid. Mutual inhibition of degradation has been reported when 2,4-D and 2,4,5-T are presented in a mixture to degrading bacteria. This paper investigates the ability of Pseudomonas chrysosporium to mineralize 2,4-D individually and in combination with 2,4,5-T. Results indicate that P. chrysosporium effectively mineralizes 2,4-D alone as well as in combination with 2,4,5-T. 31 refs., 4 figs., 1 tab.

  17. Maturational regulation of inositol 1,4,5-trisphosphate metabolism in rabbit airway smooth muscle.

    PubMed Central

    Rosenberg, S M; Berry, G T; Yandrasitz, J R; Grunstein, M M

    1991-01-01

    Airway reactivity has been shown to vary with age; however, the mechanism(s) underlying this process remain unidentified. To elucidate the role of ontogenetic changes in phosphoinositide-linked signal transduction, we examined whether age-related differences in tracheal smooth muscle (TSM) contractility to carbachol (CCh) are associated with developmental changes in the production and metabolism of the second messenger, inositol 1,4,5-trisphosphate (Ins (1,4,5)P3). In TSM segments isolated from 2-wk-old and adult rabbits, both the maximal isometric contractile force and sensitivity (i.e., -logED50) to CCh (10(-10)-10(-4) M) were significantly greater in the immature vs. adult tissues (P less than 0.001). Similarly, Ins(1,4,5)P3 accumulation elicited by either receptor-coupled stimulation with CCh (10(-10)-10(-4) M) or post-receptor-mediated guanine nucleotide binding protein activation of permeabilized TSM with GTP gamma S (100 microM) was also significantly enhanced in 2-wk-old vs. adult TSM. Measurement of the activities of the degradative enzymes for Ins(1,4,5)P3 demonstrated that: (a) mean +/- SE maximal Ins(1,4,5)P3 3'-kinase activity was significantly reduced in the immature vs. adult TSM (i.e., approximately 71.7 +/- 6.0 vs. 137.8 +/- 10.0 pmol/min per mg protein, respectively; P less than 0.005); (b) by contrast, maximal Ins(1,4,5)P3 5'-phosphatase activity was significantly increased in the immature vs. adult TSM (i.e., 27.9 +/- 1.2 vs. 15.6 +/- 1.5 nmol/min per mg protein, respectively; P less than 0.001); and (c) the Km values for Ins(1,4,5)P3 5'-phosphatase were 14- and 19-fold greater than those for Ins(1,4,5)P3 3'-kinase in the 2-wk-old and adult TSM, respectively. Collectively, the findings suggest that the age-related decrease in agonist-induced rabbit TSM contractility is associated with a diminution in Ins(1,4,5)P3 accumulation which is attributed, at least in part, to ontogenetic changes in the relative activities of the degradative enzymes for

  18. 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…

  19. Strain rate dependence of the tensile properties of V-(4--5%)Cr-(4--5%)Ti irradiated in EBR-II and HFBR

    SciTech Connect

    Zinkle, S.J.; Snead, L.L.; Robertson, J.P.; Rowcliffe, A.F.

    1998-03-01

    Elevated temperature tensile tests performed on V-(405)Cr-(4-5)Ti indicate that the yield stress increases with increasing strain rate for irradiation and test temperatures near 200 C, and decreases with increasing strain rate for irradiation and test temperatures near 400 C. This observation is in qualitative agreement with the temperature-dependent strain rate effects observed on unirradiated specimens, and implies that some interstitial solute remains free to migrate in irradiated specimens. Additional strain rate data at different temperatures are needed.

  20. 40 CFR 180.465 - 4-(Dichloroacetyl)-1-oxa-4-azaspiro[4.5]decane.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ingredient (safener) in or on the following raw agricultural commodities: Commodity 1 Parts per million Corn, field, forage 0.005 Corn, field, grain 0.005 Corn, field, stover 0.005 Corn, pop, grain 0.005 Corn,...

  1. 40 CFR 180.465 - 4-(Dichloroacetyl)-1-oxa-4-azaspiro[4.5]decane.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ingredient (safener) in or on the following raw agricultural commodities: Commodity 1 Parts per million Corn, field, forage 0.005 Corn, field, grain 0.005 Corn, field, stover 0.005 Corn, pop, grain 0.005 Corn,...

  2. 40 CFR 180.465 - 4-(Dichloroacetyl)-1-oxa-4-azaspiro[4.5]decane.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ingredient (safener) in or on the following raw agricultural commodities: Commodity 1 Parts per million Corn, field, forage 0.005 Corn, field, grain 0.005 Corn, field, stover 0.005 Corn, pop, grain 0.005 Corn,...

  3. 40 CFR 180.465 - 4-(Dichloroacetyl)-1-oxa-4-azaspiro[4.5]decane.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ingredient (safener) in or on the following raw agricultural commodities: Commodity 1 Parts per million Corn, field, forage 0.005 Corn, field, grain 0.005 Corn, field, stover 0.005 Corn, pop, grain 0.005 Corn,...

  4. PTEN interaction with tethered bilayer lipid membranes containing PI(4,5)P2

    NASA Astrophysics Data System (ADS)

    Moldovan, R.; Shenoy, S.; Shekhar, P.; Kalinowski, A.; Gericke, A.; Heinrich, F.; Loesche, M.

    2009-03-01

    Synthetic lipid membrane models are frequently used for the study of biophysical processes at cell membranes. We use a robust membrane model, the tethered bilayer lipid membrane (tBLM), based on a (C14)2-(PEO)6-thiol anchor, WC14 [1]. Such membranes can be prepared to contain single phospholipids or complex lipid mixtures [2], including functional lipids involved in cell signaling, such as the highly charged phosphatidylinositol phosphates (PIPs). To study the interaction between the tumor suppressor PTEN (phosphatase and tensin homologue deleted on chromosome 10) and model membranes we have incorporated phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) in tBLMs and use fluorescence correlation spectroscopy (FCS), neutron reflectometry (NR) and surface plasmon resonance (SPR) for their characterization. NR shows that tBLMs formed with PI(4,5)P2 are complete. FCS of labeled PI(4,5)P2 shows that diffusion occurs at the time scale characteristic of membrane-incorporated lipid. Finally, SPR shows specific binding of PTEN to the model membrane thus confirming the incorporation of PI(4,5)P2 into the tBLM. [1] McGillivray et al, Biointerphases 2, 21-33 (2007) [2] Heinrich et al, Langmuir, submitted

  5. The first 1-alkyl-3-perfluoroalkyl-4,5- dimethyl-1,2,4-triazolium salts.

    PubMed

    Xue, Hong; Twamley, Brendan; Shreeve, Jean'ne M

    2004-02-20

    Syntheses of quaternary 1-alkyl-3-perfluoroalkyl-4,5-dimethyl-1,2,4-triazolium iodides have led to a variety of new quaternary salts via metathesis reactions. 1,4,5-Trimethyl-3-trifluoro-methyl-1,2,4-triazolium iodide (6) with LiN(SO(2)CF(3))(2), KSO(3)CF(3), AgClO(4), AgBF(4); 1-(3-fluoropropyl)-3-trifluoromethyl-4,5-dimethyl-1,2,4-triazolium iodide (7) with LiN(SO(2)CF(3))(2); and 1,4,5-trimethyl-3-perfluorooctyl-1,2,4-triazolium iodide (8) with LiN(SO(2)CF(3))(2), AgClO(4), AgBF(4) gave excellent yields of new thermally stable and relatively low melting quaternary salts. The structure of 1,4,5-trimethyl-3-perfluorooctyl-1,2,4-triazolium tetrafluoroborate (11c) was confirmed by single-crystal X-ray analysis. Although the molecular weight of 11c (cation) is 3-fold greater than that of the 3-trifluoromethyl derivative 9d, its melting point is 32 degrees C lower.

  6. Physical chemistry of binary organic eutectic and monotectic alloys; 1,2,4,5-tetrachlorobenzene-β-naphthol and 1,2,4,5-tetramethylbenzene-succinonitrile systems

    NASA Astrophysics Data System (ADS)

    Rai, U. S.; Pandey, Pinky; Rai, R. N.

    2000-12-01

    Phase diagrams of 1,2,4,5-tetrachlorobenzene-β-naphthol and 1,2,4,5-tetramethylbenzene-succinonitrile systems which are organic analogues of a nonmetal-nonmetal and a nonmetal-metal system, respectively, show the formation of a simple eutectic (melting point 103.7°C) with 0.71 mole fraction of β-naphthol in the former case and a monotectic (melting point 76.0°C) with 0.07 mole fraction of succinonitrile and a eutectic (melting point 52.5°C) with 0.97 mole fraction of succinonitrile in the latter case. The growth behaviour of the pure components, the eutectics and the monotectic studied by measuring the rate of movement of the solid-liquid interface in a capillary, suggests that the data obey the Hillig-Turnbull equation, v= u(Δ T) n, where v is the growth velocity, Δ T is the undercooling and u and n are constants depending on the nature of the materials involved. From the values of enthalpy of fusion determined by the DSC method using Mettler DSC-4000 system, entropy of fusion, interfacial energy, enthalpy of mixing and excess thermodynamic functions were calculated. The optical microphotographs of pure components and polyphase materials show their characteristic features.

  7. Compatibility study of trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin (TNAD) with some energetic components and inert materials.

    PubMed

    Yan, Qi-Long; Xiao-Jiang, Li; La-Ying, Zhang; Ji-Zhen, Li; Hong-Li, Li; Zi-Ru, Liu

    2008-12-30

    The compatibility of trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin (TNAD) with some energetic components and inert materials of solid propellants was studied by using the pressure DSC method where, cyclotetramethylenetetranitroamine (HMX), cyclotrimethylenetrinitramine (RDX), 1,4-dinitropiperazine (DNP), 1.25/1-NC/NG mixture, lead 3-nitro-1,2,4-triazol-5-onate (NTO-Pb), aluminum powder (Al, particle size=13.6microm) and N-nitrodihydroxyethylaminedinitrate (DINA) were used as energetic components and polyethylene glycol (PEG), polyoxytetramethylene-co-oxyethylene (PET), addition product of hexamethylene diisocyanate and water (N-100), 2-nitrodianiline (2-NDPA), 1,3-dimethyl-1,3-diphenyl urea (C2), carbon black (C.B.), aluminum oxide (Al2O3), cupric 2,4-dihydroxy-benzoate (beta-Cu), cupric adipate (AD-Cu) and lead phthalate (phi-Pb) were used as inert materials. It was concluded that the binary systems of TNAD with NTO-Pb, RDX, PET and Al powder are compatible, and systems of TNAD with DINA and HMX are slightly sensitive, and with 2-NDPA, phi-Pb, beta-Cu, AD-Cu and Al2O3 are sensitive, and with PEG, N-100, C2 and C.B. are incompatible. The impact and friction sensitivity data of the TNAD and TNAD in combination with the other energetic materials under present study was also obtained, and there was no consequential affiliation between sensitivity and compatibility.

  8. Room-temperature fracture in V-(4-5)Cr-(4-5)Ti tensile specimens irradiated in Fusion-1 BOR-60 experiment

    SciTech Connect

    Gazda, J.; Meshii, M.; Tsai, H.

    1998-09-01

    Specimens of V-(4-5)Cr-(4-5)Ti alloys were irradiated to {approx}18 dpa at 320 C in the Fusion-1 capsule inserted into the BOR-60 reactor. Tensile tests at 23 C indicated dramatic yield strength increase (>300%), lack of work hardening, and minimal (<1%) total elongations. SEM analysis of fracture and side surfaces were conducted to determine reduction in are and the mode of fracture. The reduction of area was negligible. All but one specimen failed by a combination of ductile shear deformation and cleavage crack growth. Transgranular cleavage cracks were initiated by stress concentrations at the tips of the shear bands. In side-view observations, evidence was found of slip bands typically associated with dislocation channeling. No differences due to pre-irradiation heat treatment and heat-to-heat composition variations were detected. The only deviation from this behavior was found in V-4Cr-4Ti-B alloy, which failed in the grip portion by complete cleavage cracking.

  9. Synthesis, antitumor, and antibacterial activity of bis[4,5-diarylimidazol-2-ylidene]methane derivatives.

    PubMed

    Liu, Wukun; Chen, Xiaohua; Gust, Ronald

    2012-07-01

    Cationic [bis(1,3-diethyl-4,5-diarylimidazol-2-ylidene)]Au(I) bromide complexes have demonstrated considerable potential as new antitumor agents. In order to investigate whether the gold is crucial for the antitumor activity, the imidazole ligands were connected by a methylene bridge. Biological evaluation revealed that bis[1,3-diethyl-4,5-diarylimidazol-2-ylidene]methane compounds exhibited growth inhibition effects against mammary (MCF-7 and MDA-MB 231) and colon (HT-29) carcinoma cell lines. In comparison with gold complexes, the methylene derivatives showed drastically reduced cell growth inhibitory properties. However, the growth of bacteria was significantly inhibited by bis[1,3-diethyl-4,5-bis(4-methoxyphenyl)imidazol-2-ylidene]methane dibromide (4) and opens a new application of this compound type.

  10. Aromatic fluorine compounds. II. 1,2,4,5-Tetrafluorobenzene and related compounds

    USGS Publications Warehouse

    Finger, G.C.; Reed, F.H.; Burness, D.M.; Fort, D.M.; Blough, R.R.

    1951-01-01

    The synthesis and properties of 1,2,4,5-tetrafluorobenzene and a group of bromofluoro and chlorofluorobenzenes with a predominating 1,2,4,5-structure are described. Flash point and surface tension data for the fluorinated benzenes and the influence of chlorine substitution upon these values were studied. Under nitration conditions, 1,2,4,5-tetrafluorobenzene will not form a nitro derivative, but will undergo a preferential 1,4-fluorine displacement-oxidation mechanism to give 2,5-difluoro-1,4-benzoquinone. Diazotization reactions on 2-nitro-3,4,6-trifluoroaniline reveal that the nitro group or a fluorine atom in the 4- or 6-position may become labilized, under certain conditions, and undergo replacement.

  11. ULTRACOOL FIELD BROWN DWARF CANDIDATES SELECTED AT 4.5 {mu}m

    SciTech Connect

    Eisenhardt, Peter R. M.; Griffith, Roger L.; Stern, Daniel; Mainzer, Amy; Wright, Edward L.; Ghez, A. M.; Konopacky, Quinn; Ashby, Matthew L. N.; Brodwin, Mark; Brown, Michael J. I.; Bussmann, R. S.; Dey, Arjun; Glikman, Eilat; Gonzalez, Anthony H.; Vollbach, David; Kirkpatrick, J. Davy; Wright, Shelley A.

    2010-06-15

    We have identified a sample of cool field brown dwarf candidates using IRAC data from the Spitzer Deep, Wide-Field Survey (SDWFS). The candidates were selected from 400,000 SDWFS sources with [4.5] {<=} 18.5 mag and were required to have [3.6] - [4.5] {>=} 1.5 and [4.5] - [8.0] {<=} 2.0 on the Vega system. The first color requirement selects objects redder than all but a handful of presently known brown dwarfs with spectral classes later than T7, while the second eliminates 14 probable reddened active galactic nuclei (AGNs). Optical detection of four of the remaining 18 sources implies they are likely also AGNs, leaving 14 brown dwarf candidates. For two of the brightest candidates (SDWFS J143524.44+335334.6 and SDWFS J143222.82+323746.5), the spectral energy distributions including near-infrared detections suggest a spectral class of {approx}T8. The proper motion is <0.''25 yr{sup -1}, consistent with expectations for a luminosity-inferred distance of >70 pc. The reddest brown dwarf candidate (SDWFS J143356.62+351849.2) has [3.6] - [4.5] = 2.24 and H - [4.5] > 5.7, redder than any published brown dwarf in these colors, and may be the first example of the elusive Y-dwarf spectral class. Models from Burrows et al. predict that larger numbers of cool brown dwarfs should be found for a Chabrier mass function. Suppressing the model [4.5] flux by a factor of 2, as indicated by previous work, brings the Burrows models and observations into reasonable agreement. The recently launched Wide-field Infrared Survey Explorer will probe a volume {approx}40x larger and should find hundreds of brown dwarfs cooler than T7.

  12. Phosphatidylinositol(4,5)bisphosphate and Phosphatidylinositol(4)phosphate in Plant Tissues 1

    PubMed Central

    Irvine, R. F.; Letcher, A. J.; Lander, D. J.; Drøbak, B. K.; Dawson, A. P.; Musgrave, A.

    1989-01-01

    Pea (Pisum sativum) leaf discs or swimming suspensions of Chlamydomonas eugametos were radiolabeled with [3H]myo-inositol or [32P]Pi and the lipids were extracted, deacylated, and their glycerol moieties removed. The resulting inositol trisphosphate and bisphosphate fractions were examined by periodate degradation, reduction and dephosphorylation, or by incubation with human red cell membranes. Their likely structures were identified as d-myo-inositol(1,4,5)trisphosphate and d-myo-inositol(1,4,)-bisphosphate. It is concluded that plants contain phosphatidylinositol(4)phosphate and phosphatidylinositol(4,5)bisphosphate; no other polyphosphoinositides were detected. PMID:16666637

  13. Regulation of voltage-gated potassium channels by PI(4,5)P2

    PubMed Central

    Kruse, Martin; Hammond, Gerald R.V.

    2012-01-01

    Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) regulates activities of numerous ion channels including inwardly rectifying potassium (Kir) channels, KCNQ, TRP, and voltage-gated calcium channels. Several studies suggest that voltage-gated potassium (KV) channels might be regulated by PI(4,5)P2. Wide expression of KV channels in different cells suggests that such regulation could have broad physiological consequences. To study regulation of KV channels by PI(4,5)P2, we have coexpressed several of them in tsA-201 cells with a G protein–coupled receptor (M1R), a voltage-sensitive lipid 5-phosphatase (Dr-VSP), or an engineered fusion protein carrying both lipid 4-phosphatase and 5-phosphatase activity (pseudojanin). These tools deplete PI(4,5)P2 with application of muscarinic agonists, depolarization, or rapamycin, respectively. PI(4,5)P2 at the plasma membrane was monitored by Förster resonance energy transfer (FRET) from PH probes of PLCδ1 simultaneously with whole-cell recordings. Activation of Dr-VSP or recruitment of pseudojanin inhibited KV7.1, KV7.2/7.3, and Kir2.1 channel current by 90–95%. Activation of M1R inhibited KV7.2/7.3 current similarly. With these tools, we tested for potential PI(4,5)P2 regulation of activity of KV1.1/KVβ1.1, KV1.3, KV1.4, and KV1.5/KVβ1.3, KV2.1, KV3.4, KV4.2, KV4.3 (with different KChIPs and DPP6-s), and hERG/KCNE2. Interestingly, we found a substantial removal of inactivation for KV1.1/KVβ1.1 and KV3.4, resulting in up-regulation of current density upon activation of M1R but no changes in activity upon activating only VSP or pseudojanin. The other channels tested except possibly hERG showed no alteration in activity in any of the assays we used. In conclusion, a depletion of PI(4,5)P2 at the plasma membrane by enzymes does not seem to influence activity of most tested KV channels, whereas it does strongly inhibit members of the KV7 and Kir families. PMID:22851677

  14. Phosphatidylinositol(4,5)bisphosphate and phosphatidylinositol(4)phosphate in plant tissues. [Pisum sativum

    SciTech Connect

    Irvine, R.F.; Letcher, A.J.; Lander, D.J. ); Dawson, A.P. ); Musgrave, A. ); Drobak, B.K. )

    1989-03-01

    Pea (Pisum sativum) leaf discs or swimming suspensions of Chlamydomonas eugametos were radiolabeled with ({sup 3}H)myo-inositol or ({sup 32}P)Pi and the lipids were extracted, deacylated, and their glycerol moieties removed. The resulting inositol trisphosphate and bisphosphate fractions were examined by periodate degradation, reduction and dephosphorylation, or by incubation with human red cell membranes. Their likely structures were identified as D-myo-inositol(1,4,5)trisphosphate and D-myo-inositol(1,4,)-bisphosphate. It is concluded that plants contain phosphatidylinositol(4)phosphate and phosphatidylinositol(4,5)bisphosphate; no other polyphosphoinositides were detected.

  15. Characteristics of 2,4,5,2',4',5'-hexachlorobiphenyl distribution among lipoproteins in vitro. [Rats and human whole blood, plasma, and lipoprotein fractions

    SciTech Connect

    Vomachka, M.S.; Vodicnik, M.J.; Lech, J.J.

    1983-09-01

    The uptake, distribution, and transfer of 2,4,5,2',4',5'-hexachlorobiphenyl (6-CB) were examined in vitro with human and rat whole blood, plasma, and lipoprotein fractions. 6-CB distribution between plasma and erythrocytes as well as among lipoproteins was determined following sedimentation of erythrocytes and ultracentrifugal fractionation of plasma. In both rat and human whole blood, 70 to 75% of 6-CB partitioned into plasma and 25 to 30% into erythrocytes. The uptake of 6-CB into plasma was extremely rapid and the rate of uptake was found to be dependent upon temperature. The distribution of 6-CB among lipoproteins was relatively homogeneous with 20 to 30% being distributed in very low-density lipoproteins (VLDL, d . 0.95-1.006 g/ml), 15 to 20% in low-density lipoproteins (LDL, d . 1.006-1.063 g/ml), and 15 to 25% in high-density lipoproteins (HDL, d . 1.063-1.21 g/ml). Over 25% of 6-CB was found in the remaining bottom fraction. In addition, each isolated fraction when incubated alone with 6-CB was shown capable of uptake. The relative proportion of 6-CB among the lipoproteins was independent of the level taken up by plasma. 6-CB was also found to transfer among lipoproteins. This exchange of 6-CB proved to be dependent upon the concentrations of both protein and triacylglycerol in the incubations. Two proteins in the bottom fraction (Bf), albumin and a steroid binding globulin, were capable of competing with the lipoproteins for 6-CB uptake.

  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.

    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.

  17. Physical Education, Junior Division: Grades 4, 5, 6. Curriculum J.5.

    ERIC Educational Resources Information Center

    Ontario Dept. of Education, Toronto.

    This manual was prepared to give teachers assistance in carrying out programs in physical education in grades 4, 5, and 6. Because many schools have space and equipment deficiencies, some emphasis has been placed on improvisation and the fullest possible use of available space and equipment. The manual is divided into two sections: organization…

  18. Synthesis of inositol phosphate-based competitive antagonists of inositol 1,4,5-trisphosphate receptors.

    PubMed

    Konieczny, Vera; Stefanakis, John G; Sitsanidis, Efstratios D; Ioannidou, Natalia-Anastasia T; Papadopoulos, Nikolaos V; Fylaktakidou, Konstantina C; Taylor, Colin W; Koumbis, Alexandros E

    2016-02-28

    Inositol 1,4,5-trisphosphate receptors (IP3Rs) are intracellular Ca(2+) channels that are widely expressed in animal cells, where they mediate the release of Ca(2+) from intracellular stores evoked by extracellular stimuli. A diverse array of synthetic agonists of IP3Rs has defined structure-activity relationships, but existing antagonists have severe limitations. We combined analyses of Ca(2+) release with equilibrium competition binding to IP3R to show that (1,3,4,6)IP4 is a full agonist of IP3R1 with lower affinity than (1,4,5)IP3. Systematic manipulation of this meso-compound via a versatile synthetic scheme provided a family of dimeric analogs of 2-O-butyryl-(1,3,4,6)IP4 and (1,3,4,5,6)IP5 that compete with (1,4,5)IP3 for binding to IP3R without evoking Ca(2+) release. These novel analogs are the first inositol phosphate-based competitive antagonists of IP3Rs with affinities comparable to that of the only commonly used competitive antagonist, heparin, the utility of which is limited by off-target effects.

  19. 60. MISSISSIPPI, NOXUBEE CO. MACON MAHORNER' S BRIDGE, 1884, 4.5 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    60. MISSISSIPPI, NOXUBEE CO. MACON MAHORNER' S BRIDGE, 1884, 4.5 miles S on McLeod-Shuqualak road. Bottom of swing span and top of center pier. Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  20. 2,2\\',4,4\\',5,5\\'-Hexabromodiphenyl ether (BDE-153)

    Integrated Risk Information System (IRIS)

    2,2 ' , 4,4 ' , 5,5 ' - Hexabromodiphenyl ether ( BDE - 153 ) ; CASRN 68631 - 49 - 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 (

  1. 2,2\\',3,3\\',4,4\\',5,5\\',6,6\\'-Decabromodiphenyl ether (BDE-209)

    Integrated Risk Information System (IRIS)

    2,2 ' , 3,3 ' , 4,4 ' , 5,5 ' , 6,6 ' - Decabromodiphenyl ether ( BDE - 209 ) ; CASRN 1163 - 19 - 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

  2. The Role of PI(3,4,5)P3 Signaling During Axonal Growth Cone Chemotaxis

    NASA Astrophysics Data System (ADS)

    Henle, Steven J.

    Development of the nervous system is a remarkably complex process that involves the birth of billions of neurons leading to the formation of trillions of synapses. Many biological programs underlie the formation of a functional nervous system. I focused on trying to understand the process by which a newly formed axon navigates a series of signals in the environment that guide it to a synaptic partner. At the tip of the extending neurite is a conical expansion known as the growth cone that primarily is responsible for performing this pathfinding process. In order to do so it senses the environment, and induces a program of intracellular signaling that in turn leads to directed axon extension. My work has focused on understanding this signaling machinery. I have aimed to understand the role the phosphoinositde PI(3,4,5)P3 due to the critical role it plays in amoeboid chemotaxis. I discovered that PI(3,4,5)P3 and its downstream kinase Akt define the leading edge during growth cone chemotaxis and lead to activation of a TRP (Transient Receptor Potential) channel. Furthermore, I found that the PI(3,4,5)P3 phosphatase PTEN appears to be exclusively linked to guiding growth cone migration in response to a gradient of chemorepellent. Taken together my data demonstrate that PI(3,4,5)P3 functions as a key instructive mediator of growth cone chemotaxis.

  3. Preparation of 3,3'-azobis(6-amino-1,2,4,5-tetrazine)

    DOEpatents

    Hiskey, Michael A.; Chavez, David E.; Naud, Darren

    2002-01-01

    The compound of the structure ##STR1## where a, b, c, d and e are 0 or 1 and a+b+c+d+e is from 0 to 5 is disclosed together with the species 3,3'-azobis(6-amino-1,2,4,5-tetrazine) and a process of preparing such compounds.

  4. Characterization of Ffh of Mycobacterium tuberculosis and its interaction with 4.5S RNA.

    PubMed

    Palaniyandi, Kannan; Veerasamy, Malini; Narayanan, Sujatha

    2012-10-12

    Signal recognition particle (SRP) mediates targeting of proteins to appropriate cellular compartments, which is an important process in all living organisms. In prokaryotes, SRP consists of Ffh, a protein, and 4.5S RNA that recognizes signal peptide emerging from ribosomes. The SRP (Ffh) of one the most successful intracellular pathogen, Mycobacterium tuberculosis, has been investigated with respect to biochemical properties. In the present study, Ffh of M. tuberculosis was overexpressed and was confirmed to be a GTPase using thin layer chromatography and malachite green assay. The GTP binding ability was confirmed by GTP overlay assay. The 4.5S RNA sequence of M. tuberculosis was synthesized by in vitro transcription assay. The interaction between Ffh and 4.5S RNA was confirmed by overlay assay and RNA gel shift assay. The results show that the biochemical properties of M. tuberculosis Ffh have been conserved, and this is the first report that shows the interaction of components of SRP in M. tuberculosis, namely Ffh protein and 4.5S RNA.

  5. Mathematics Pentathlon. A Manual of Directions and Official Tournament Rules. Division III. Grades 4-5.

    ERIC Educational Resources Information Center

    del Regato, John C.; And Others

    The Mathematics Pentathlon is a tournament of mathematics games held each spring since 1979 to promote the development of mathematical concepts and skills while fostering interaction among the educational community. There are five games in each of four divisions, for grades K-1, 2-3, 4-5, and 6-7. The focus is on active problem solving and…

  6. Bifunctional Ag/C3N4.5 composite nanobelts for photocatalysis and antibacterium.

    PubMed

    Lei, Renbo; Jian, Jikang; Zhang, Zhihua; Song, Bo; Wu, Rong

    2016-09-30

    Multiple functions can be achieved in carbon nitride-based composite nanomaterials by tuning their components and structures. Here, we report on a large-scale synthesis of novel bifunctional Ag/C3N4.5 composite nanobelts (CNBs) with efficient photocatalytic and antibacterial activity. The Ag/C3N4.5 CNBs were synthesized in high yield by a two-step route including a homogeneous precipitation process and a subsequent calcination treatment. The structural, morphological, compositional, and spectroscopic characterizations revealed that the Ag/C3N4.5 CNBs are composed of N-deficient melem ultrathin nanobelts and crystalline Ag nanoparticles attached to the surface of the nanobelts with good contact. The band gap of the Ag/C3N4.5 CNBs is determined to be about 3.04 eV. The efficient photocatalytic and antibacterial activities of the composite nanomaterials are verified by testing the degradation of Rhodamine B (RhB) and the inhibition zone to bacterium E. coli. The work provides a facile route to bifunctional carbon nitride-based composites with potential applications in the fields of the environment and biology.

  7. Netscape Communicator 4.5. Volume I: The Basic Functions of the Navigator Component.

    ERIC Educational Resources Information Center

    Gallo, Gail; Wichowski, Chester P.

    This first of two guides on Netscape Communicator 4.5 contains six lessons on the basic functions of the Navigator component. Lesson 1 covers terminology and methods to connect to the World Wide Web, hardware needed, and a Netscape Communicator overview. Lesson 2 introduces the Navigator window, toolbars, and menus, and how to change the default…

  8. Priming 4.5-Month-Old Infants to Use Height Information by Enhancing Retrieval

    ERIC Educational Resources Information Center

    Wang, Su-hua

    2011-01-01

    How do infants select and use information that is relevant to the task at hand? Infants treat events that involve different spatial relations as distinct, and their selection and use of object information depends on the type of event they encounter. For example, 4.5-month-olds consider information about object height in occlusion events, but…

  9. Strand I: Physical Health. Sensory Perception. Health Curriculum Materials Grades 4, 5, 6.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of Elementary Curriculum Development.

    GRADES OR AGES: Grades 4, 5, and 6. SUBJECT MATTER: Sensory perceptions, the organs involved, and eye and hearing care. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is divided into six different sectional steps organized around a gradual, ascending understanding of the sense organs. OBJECTIVES AND ACTIVITIES: The material is divided into…

  10. Fragmentation of silicon nuclei at 4. 5 A GeV/c

    SciTech Connect

    Ahmad, T.; Irfan, M. )

    1991-11-30

    1024 interactions caused by 4.5 A GeV/c {sup 28}Si in emulsion are studied. In this paper result on the mean free path is discussed and compared with the corresponding results obtained for the interactions initiated by other projectiles. Multiplicity distributions for Z = 1, 2 and {ge}3 fragments are also investigated.

  11. 17 CFR 275.206(4)-5 - Political contributions by certain investment advisers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... investment adviser that has reported on its annual updating amendment to Form ADV (17 CFR 279.1) that it has... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Political contributions by....206(4)-5 Political contributions by certain investment advisers. (a) Prohibitions. As a...

  12. 17 CFR 275.206(4)-5 - Political contributions by certain investment advisers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... investment adviser that has reported on its annual updating amendment to Form ADV (17 CFR 279.1) that it has... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Political contributions by....206(4)-5 Political contributions by certain investment advisers. (a) Prohibitions. As a...

  13. 17 CFR 275.206(4)-5 - Political contributions by certain investment advisers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... investment adviser that has reported on its annual updating amendment to Form ADV (17 CFR 279.1) that it has... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Political contributions by....206(4)-5 Political contributions by certain investment advisers. (a) Prohibitions. As a...

  14. 17 CFR 275.206(4)-5 - Political contributions by certain investment advisers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... investment adviser that has reported on its annual updating amendment to Form ADV (17 CFR 279.1) that it has... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Political contributions by....206(4)-5 Political contributions by certain investment advisers. (a) Prohibitions. As a...

  15. Synthetic studies towards Zetekitoxin AB: preparation of 4,5-epi-11-hydroxy-saxitoxinol

    PubMed Central

    Pearson, Aaron D.; Williams, Robert M.

    2014-01-01

    A concise synthesis of 4,5-epi-11-hydroxy-saxitoxinol utilizing D-ribose to direct an asymmetric Mannich reaction. This approach allows many modes of reactivity, which can be used to access various analogs of saxitoxin. PMID:25313264

  16. Bifunctional Ag/C3N4.5 composite nanobelts for photocatalysis and antibacterium

    NASA Astrophysics Data System (ADS)

    Lei, Renbo; Jian, Jikang; Zhang, Zhihua; Song, Bo; Wu, Rong

    2016-09-01

    Multiple functions can be achieved in carbon nitride-based composite nanomaterials by tuning their components and structures. Here, we report on a large-scale synthesis of novel bifunctional Ag/C3N4.5 composite nanobelts (CNBs) with efficient photocatalytic and antibacterial activity. The Ag/C3N4.5 CNBs were synthesized in high yield by a two-step route including a homogeneous precipitation process and a subsequent calcination treatment. The structural, morphological, compositional, and spectroscopic characterizations revealed that the Ag/C3N4.5 CNBs are composed of N-deficient melem ultrathin nanobelts and crystalline Ag nanoparticles attached to the surface of the nanobelts with good contact. The band gap of the Ag/C3N4.5 CNBs is determined to be about 3.04 eV. The efficient photocatalytic and antibacterial activities of the composite nanomaterials are verified by testing the degradation of Rhodamine B (RhB) and the inhibition zone to bacterium E. coli. The work provides a facile route to bifunctional carbon nitride-based composites with potential applications in the fields of the environment and biology.

  17. Low-molecular-weight (4.5S) ribonucleic acid in higher-plant chloroplast ribosomes.

    PubMed Central

    Whitfeld, P R; Leaver, C J; Bottomley, W; Atchison, B

    1978-01-01

    A species of RNA that migrates on 10% (w/v) polyacrylamide gels between 5S and 4S RNA was detected in spinach chloroplasts. This RNA (referred to as 4.5 S RNA) was present in amounts equimolar to the 5S RNA and its molecular weight was estimated to be approx. 33 000. Fractionation of the chloroplast components showed that the 4.5S RNA was associated with the 50 S ribosomal subunit and that it could be removed by washing the ribosomes with a buffer containing 0.01 M-EDTA and 0.5 M-KCl. It did not appear to be a cleavage product of the labile 23 S RNA of spinach chloroplast ribosomes. When 125I-labelled 4.5 S RNA was hybridized to fragments of spinach chloroplast DNA produced by SmaI restriction endonuclease, a single fragment (mol.wt. 1.15 times 10(6)) became labelled. The same DNA fragment also hybridized to chloroplast 5 S RNA and part of the 23 S RNA. It was concluded that the coding sequence for 4.5 S RNA was part of, or immediately adjacent to, the rRNA-gene region in chloroplast DNA . A comparable RNA species was observed in chloroplasts of tobacco and pea leaves. Images Fig. 8. PMID:743229

  18. 42 CFR 4.5 - Use of materials from the collections.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... materials directly to health-sciences professionals. An individual wishing a loan of library materials must... NATIONAL LIBRARY OF MEDICINE § 4.5 Use of materials from the collections. (a) Unrestricted materials... any interested person only in facilities provided by the Library for this purpose. The Director...

  19. Lymphocele formation after anterior lumbar interbody fusion at L4-5. Case report.

    PubMed

    Pee, Yong Hun; Kim, Ki Joon; Choi, Young-Geun; Jeon, Sang Hyeop; Park, Jong Dae; Lee, Sang-Ho

    2007-11-01

    In this report, the authors present the case of patient with a lymphocele in the retroperitoneal area following anterior lumbar interbody fusion at L4-5. A lymphocele is a rare complication of spinal operations, especially lower lumbar spinal surgeries. The authors discuss this complicating factor and describe its features and treatments.

  20. Synthesis and antifungal activity of natural product-based 6-alkyl-2 3 4 5-tetrahydropyridines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven 6-alkyl-2,3,4,5-tetrahydropyridines (5a–5g) that mimic the natural products piperideines that were recently identified in the fire ant venom have been synthesized. Compounds 5c–5g with the C-6 alkyl chain lengths from C14 to C18 showed varying degrees of antifungal activities, with 5e (6-hexa...