Science.gov

Sample records for fourteen billion years

  1. Fourteen years in resistance.

    PubMed

    Livermore, David M

    2012-04-01

    Resistance trends have changed greatly over the 14 years (1997-2011) whilst I was Director of the UK Antibiotic Resistance Monitoring and Reference Laboratory (ARMRL). Meticillin-resistant Staphylococcus aureus (MRSA) first rose, then fell with improved infection control, although with the decline of one major clone beginning before these improvements. Resistant pneumococci too have declined following conjugate vaccine deployment. If the situation against Gram-positive pathogens has improved, that against Gram-negatives has worsened, with the spread of (i) quinolone- and cephalosporin-resistant Enterobacteriaceae, (ii) Acinetobacter with OXA carbapenemases, (iii) Enterobacteriaceae with biochemically diverse carbapenemases and (iv) gonococci resistant to fluoroquinolones and, latterly, cefixime. Laboratory, clinical and commercial aspects have also changed. Susceptibility testing is more standardised, with pharmacodynamic breakpoints. Treatments regimens are more driven by guidelines. The industry has fewer big profitable companies and more small companies without sales income. There is good and bad here. The quality of routine susceptibility testing has improved, but its speed has not. Pharmacodynamics adds science, but over-optimism has led to poor dose selection in several trials. Guidelines discourage poor therapy but concentrate selection onto a diminishing range of antibiotics, threatening their utility. Small companies are more nimble, but less resilient. Last, more than anything, the world has changed, with the rise of India and China, which account for 33% of the world's population and increasingly provide sophisticated health care, but also have huge resistance problems. These shifts present huge challenges for the future of chemotherapy and for the edifice of modern medicine that depends upon it. PMID:22386741

  2. 29 CFR 570.119 - Fourteen-year minimum.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Fourteen-year minimum. 570.119 Section 570.119 Labor... Provisions of the Fair Labor Standards Act of 1938, as Amended Oppressive Child Labor § 570.119 Fourteen-year... orders lowering the age minimum to 14 years where he or she finds that such employment is confined...

  3. 29 CFR 779.507 - Fourteen-year minimum.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Fourteen-year minimum. 779.507 Section 779.507 Labor... § 779.507 Fourteen-year minimum. (a) Prohibited occupations. With respect to employment in occupations... the age minimum to 14 years where he finds that such employment is confined to periods which will...

  4. 29 CFR 779.507 - Fourteen-year minimum.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Fourteen-year minimum. 779.507 Section 779.507 Labor... § 779.507 Fourteen-year minimum. (a) Prohibited occupations. With respect to employment in occupations... the age minimum to 14 years where he finds that such employment is confined to periods which will...

  5. 29 CFR 570.119 - Fourteen-year minimum.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Fourteen-year minimum. 570.119 Section 570.119 Labor... Provisions of the Fair Labor Standards Act of 1938, as Amended Oppressive Child Labor § 570.119 Fourteen-year... orders lowering the age minimum to 14 years where he or she finds that such employment is confined...

  6. 29 CFR 570.119 - Fourteen-year minimum.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Fourteen-year minimum. 570.119 Section 570.119 Labor... Provisions of the Fair Labor Standards Act of 1938, as Amended Oppressive Child Labor § 570.119 Fourteen-year... orders lowering the age minimum to 14 years where he or she finds that such employment is confined...

  7. 29 CFR 779.507 - Fourteen-year minimum.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Fourteen-year minimum. 779.507 Section 779.507 Labor... § 779.507 Fourteen-year minimum. (a) Prohibited occupations. With respect to employment in occupations... the age minimum to 14 years where he finds that such employment is confined to periods which will...

  8. First Fourteen Years of Lake Mead

    USGS Publications Warehouse

    Thomas, Harold E.

    1954-01-01

    This circular summarizes the results of recent studies of Lake Mead and its environs. Area-capacity tables, prepared on the basis of a hydrographic survey of the lake in 1948-49, show that the capacity of the reservoir was reduced 4.9 percent during the first 14 years after Hoover Dam was completed, but the usable capacity was reduced only 3.2 percent. Practically all of this reduction was caused by accumulation of sediment in the reservoir. Studies of inflow and outflow indicate that the reservoir has a total storage capacity about 12 percent greater than that shown by the area-capacity table, because of 'bank' storage, or ground-water storage in the bottom and sides of the reservoir. Thus the total capacity in 1949 was greater than the quantity shown by the original area-capacity table, even though large quantities of sediment had been deposited in the reservoir during the 14 years. According to computations of the volume and weight of the accumulated sediment, about 2,000 million tons were deposited in the reservoir by the Colorado River in 14 years; this is within 2 percent of the amount calculated from measurements of the suspended sediment carried by the in flowing rivers. It is estimated that the sediment capacity of the reservoir, when filled to the level of the permanent spillway crest, is about 75,000 million tons. The sediment contributed by the Colorado River averages about 45 percent sand and 55 percent silt and clay. If the sediment carried by the river in the years 1926-50 represents the long-term average rate of accumulation in Lake Mead, it will be a century before the sediment at the dam reaches the level of the lowest gates in the intake towers, and more than 4 centuries before the reservoir is filled with sediment to the level of the permanent spillway crest. The rate of sedimentation since the first year of Lake Mead (1935) has been about 20 percent lower, and if that rate continues in the future, the life of the reservoir will be

  9. Fourteen Years of Atomic Hydrogen from SABER

    NASA Astrophysics Data System (ADS)

    Hunt, L. A.; Mlynczak, M. G.

    2015-12-01

    We present results for atomic hydrogen in the mesopause region (80-100 km) derived from measurements made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the TIMED satellite. SABER has been measuring the vertical distribution of infrared radiation emitted by various atmospheric gases for nearly 14 years, providing important information about chemical species, including atomic oxygen, atomic hydrogen, ozone and hydroxyl; temperature; and the radiation budget in the upper atmosphere. The methodology for the derivation of daytime and nighttime concentrations and volume mixing ratios will be presented. Zonal mean and global average daytime and nighttime concentrations of H, which demonstrate excellent agreement between 87 and 95 km, have been calculated and the results are compared with observations from the Solar Mesosphere Explorer (SME) satellite made nearly 30 years ago. Variability over the course of the SABER mission will be shown, including the apparent inverse dependence on the solar cycle, which stems from the temperature dependence of various reaction rate coefficients for H photochemistry. Results for H near solar max will be compared for Solar Cycles 23 and 24.

  10. Fourteen years of resonance of Vanguard orbits

    NASA Technical Reports Server (NTRS)

    Wagner, C. A.

    1975-01-01

    Tracking of Vanguard 3 and the Vanguard 2 rocket with Baker-Nunn cameras and the U.S. Navy's Space Surveillance (radio interferometer) system over a 14 year period revealed resonant fluctuations of up to 0.035 deg in inclination (peak to peak). Six geopotential terms (lumped coefficients) of 11th order and three of 22nd order were measured using orbit inclinations derived from this tracking record. The terms of 11th order are significantly smaller than Kaula's rule. (The lumped coefficients are sensitive to geopotential effects as high as 37th degree.) These observed terms are compatible with a recent 27-satellite geopotential solution whose formal coefficient errors are increased by a factor of 3.3.

  11. 29 CFR 779.507 - Fourteen-year minimum.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Fourteen-year minimum. 779.507 Section 779.507 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS THE FAIR LABOR STANDARDS ACT AS APPLIED TO RETAILERS OF GOODS OR SERVICES...

  12. 29 CFR 779.507 - Fourteen-year minimum.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... RETAILERS OF GOODS OR SERVICES Other Provisions Which May Affect Retail Enterprises Child Labor Provisions... to other specified limits. Under the provisions of Child Labor Regulations, subpart C (§§ 570.31... 29 Labor 3 2014-07-01 2014-07-01 false Fourteen-year minimum. 779.507 Section 779.507...

  13. 29 CFR 570.119 - Fourteen-year minimum.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Fourteen-year minimum. 570.119 Section 570.119 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS CHILD LABOR REGULATIONS, ORDERS AND STATEMENTS OF INTERPRETATION General Statements of Interpretation of the Child Labor Provisions of the Fair...

  14. Atmospheric oxygenation three billion years ago.

    PubMed

    Crowe, Sean A; Døssing, Lasse N; Beukes, Nicolas J; Bau, Michael; Kruger, Stephanus J; Frei, Robert; Canfield, Donald E

    2013-09-26

    It is widely assumed that atmospheric oxygen concentrations remained persistently low (less than 10(-5) times present levels) for about the first 2 billion years of Earth's history. The first long-term oxygenation of the atmosphere is thought to have taken place around 2.3 billion years ago, during the Great Oxidation Event. Geochemical indications of transient atmospheric oxygenation, however, date back to 2.6-2.7 billion years ago. Here we examine the distribution of chromium isotopes and redox-sensitive metals in the approximately 3-billion-year-old Nsuze palaeosol and in the near-contemporaneous Ijzermyn iron formation from the Pongola Supergroup, South Africa. We find extensive mobilization of redox-sensitive elements through oxidative weathering. Furthermore, using our data we compute a best minimum estimate for atmospheric oxygen concentrations at that time of 3 × 10(-4) times present levels. Overall, our findings suggest that there were appreciable levels of atmospheric oxygen about 3 billion years ago, more than 600 million years before the Great Oxidation Event and some 300-400 million years earlier than previous indications for Earth surface oxygenation. PMID:24067713

  15. Thirteen billion years in half an hour

    NASA Astrophysics Data System (ADS)

    Bassett, Bruce A.

    2005-10-01

    We take a high-speed tour of the approximately thirteen billion-year history of our universe focusing on unsolved mysteries and the key events that have sculpted and shaped it - from inflation in the first split second to the dark energy which is currently causing the expansion of the cosmos to accelerate.

  16. Circadian biology: a 2.5 billion year old clock.

    PubMed

    Loudon, Andrew S I

    2012-07-24

    A recent study suggests that circadian clocks may have evolved at the time of the Great Oxidation Event 2.5 billion years ago in order to drive detoxification of reactive oxygen species. PMID:22835791

  17. Fourteen Years of the Hubble Space Telescope's Advanced Camera for Surveys : Calibration Update

    NASA Astrophysics Data System (ADS)

    Grogin, Norman A.; HST Advanced Camera for Surveys Instrument Team

    2016-06-01

    The Advanced Camera for Surveys (ACS) has been a workhorse HST imager for over fourteen years, subsequent to its Servicing Mission 3B installation in 2002. The once defunct ACS Wide Field Channel (WFC) has now been operating considerably longer (>7yrs) since its Servicing Mission 4 repair than it had originally operated (<5yrs) prior to its 2007 failure. Despite the accumulating radiation damage to the WFC CCDs during their long stay in low Earth orbit, ACS continues to be heavily exploited by the HST community as both a prime and a parallel detector. Conspicuous recent examples include the HST Multi-cycle Treasury programs, and the ongoing HST Frontier Fields (HFF) program.We review recent developments in ACS calibration that enable the continued high performance of this instrument, including both the Wide Field Channel (WFC) and the Solar Blind Channel (WFC). Highlights include: 1) redefined WFC subarray modes to allow for more consistent high-fidelity calibration; 2) LED post-flashing the WFC darks to compensate for worsening WFC charge-transfer efficiency (CTE); 3) long term hot- and warm-pixel WFC stability analyses; and 4) refined characterization of the extended SBC point spread function and long-term SBC flatfield stability.

  18. Conservation of protein structure over four billion years.

    PubMed

    Ingles-Prieto, Alvaro; Ibarra-Molero, Beatriz; Delgado-Delgado, Asuncion; Perez-Jimenez, Raul; Fernandez, Julio M; Gaucher, Eric A; Sanchez-Ruiz, Jose M; Gavira, Jose A

    2013-09-01

    Little is known about the evolution of protein structures and the degree of protein structure conservation over planetary time scales. Here, we report the X-ray crystal structures of seven laboratory resurrections of Precambrian thioredoxins dating up to approximately four billion years ago. Despite considerable sequence differences compared with extant enzymes, the ancestral proteins display the canonical thioredoxin fold, whereas only small structural changes have occurred over four billion years. This remarkable degree of structure conservation since a time near the last common ancestor of life supports a punctuated-equilibrium model of structure evolution in which the generation of new folds occurs over comparatively short periods and is followed by long periods of structural stasis. PMID:23932589

  19. Conservation of protein structure over four billion years

    PubMed Central

    Ingles-Prieto, Alvaro; Ibarra-Molero, Beatriz; Delgado-Delgado, Asuncion; Perez-Jimenez, Raul; Fernandez, Julio M.; Gaucher, Eric A.; Sanchez-Ruiz, Jose M.; Gavira, Jose A.

    2013-01-01

    SUMMARY Little is known with certainty about the evolution of protein structures in general and the degree of protein structure conservation over planetary time scales in particular. Here we report the X-ray crystal structures of seven laboratory resurrections of Precambrian thioredoxins dating back up to ~4 billion years before present. Despite considerable sequence differences compared with extant enzymes, the ancestral proteins display the canonical thioredoxin fold while only small structural changes have occurred over 4 billion years. This remarkable degree of structure conservation since a time near the last common ancestor of life supports a punctuated-equilibrium model of structure evolution in which the generation of new folds occurs over comparatively short periods of time and is followed by long periods of structural stasis. PMID:23932589

  20. Galaxy Evolution over the Last Eight Billion Years

    NASA Astrophysics Data System (ADS)

    Zhu, Guangtun; Blanton, M. R.; Hogg, D. W.; Eisenstein, D. J.; Coil, A. L.; Cool, R. J.; Moustakas, J.; Wong, K. C.

    2011-01-01

    We study galaxy evolution over the last eight billion years with large, deep galaxy surveys, PRIMUS, SDSS and DEEP2. Galaxies have changed dramatically over this period of time. The global star formation rate has declined by roughly an order-of-magnitude. Red galaxies have grown substantially in number and mass. Blue galaxies have faded and grown redder as their star formation rate dropped. I demonstrate these evolutionary features with new results from these surveys. I also introduce PRIMUS, the largest faint galaxy survey to date. We have measured 140,000 robust redshifts to the depths of i (AB) 23 up to z 1, covering 9.1 square degrees of the sky. I show that with the existing deep multi-wavelength imaging in PRIMUS fields we are able to study the evolution in greater detail and investigate proposed physical mechanisms responsible for the evolution.

  1. Orbital forcing of climate 1.4 billion years ago.

    PubMed

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

    2015-03-24

    Fluctuating climate is a hallmark of Earth. As one transcends deep into Earth time, however, both the evidence for and the causes of climate change become difficult to establish. We report geochemical and sedimentological evidence for repeated, short-term climate fluctuations from the exceptionally well-preserved ∼1.4-billion-year-old Xiamaling Formation of the North China Craton. We observe two patterns of climate fluctuations: On long time scales, over what amounts to tens of millions of years, sediments of the Xiamaling Formation record changes in geochemistry consistent with long-term changes in the location of the Xiamaling relative to the position of the Intertropical Convergence Zone. On shorter time scales, and within a precisely calibrated stratigraphic framework, cyclicity in sediment geochemical dynamics is consistent with orbital control. In particular, sediment geochemical fluctuations reflect what appear to be orbitally forced changes in wind patterns and ocean circulation as they influenced rates of organic carbon flux, trace metal accumulation, and the source of detrital particles to the sediment. PMID:25775605

  2. Orbital forcing of climate 1.4 billion years ago

    PubMed Central

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

    2015-01-01

    Fluctuating climate is a hallmark of Earth. As one transcends deep into Earth time, however, both the evidence for and the causes of climate change become difficult to establish. We report geochemical and sedimentological evidence for repeated, short-term climate fluctuations from the exceptionally well-preserved ∼1.4-billion-year-old Xiamaling Formation of the North China Craton. We observe two patterns of climate fluctuations: On long time scales, over what amounts to tens of millions of years, sediments of the Xiamaling Formation record changes in geochemistry consistent with long-term changes in the location of the Xiamaling relative to the position of the Intertropical Convergence Zone. On shorter time scales, and within a precisely calibrated stratigraphic framework, cyclicity in sediment geochemical dynamics is consistent with orbital control. In particular, sediment geochemical fluctuations reflect what appear to be orbitally forced changes in wind patterns and ocean circulation as they influenced rates of organic carbon flux, trace metal accumulation, and the source of detrital particles to the sediment. PMID:25775605

  3. 3.5 billion years of reshaped Moho, southern Africa

    NASA Astrophysics Data System (ADS)

    Stankiewicz, Jacek; de Wit, Maarten

    2013-12-01

    According to some previous studies, Archean continental crust is, on global average, apparently thinner than Proterozoic crust. Subsequently, the validity of this statement has been questioned. To provide an additional perspective on this issue, we present analyses of Moho signatures derived from recent seismic data along swaths 2000 km in length across southern Africa and its flanking ocean. The imaged crust has a near continuous age range between ca. 0.1 and 3.7 billion years, and the seismic data allow direct comparison of Moho depths between adjacent Archean, Proterozoic and Phanerozoic crust. We find no simple secular change in depth to Moho over this time period. In contrast, there is significant variation in depth to Moho beneath both Archean and Proterozoic crust; Archean crust of southern Africa displays as much crustal diversity in thickness as the adjacent Proterozoic crust. The Moho beneath all crustal provinces that we have analysed has been severely altered by tectono-metamorphic and igneous processes, in many cases more than once, and cannot provide unequivocal data for geodynamic models dealing with secular changes in continental crust formation. These results and conclusions are similar to those documented along ca. 2000 km swaths across the Canadian Shield recorded by Lithoprobe. Tying the age and character of the Precambrian crust of southern Africa to their depth diversities is clearly related to manifold processes of tectono-thermal ‘surgery’ subsequent to their origin, the details of which are still to be resolved, as they are in most Precambrian terranes. Reconstructing pristine Moho of the early Earth therefore remains a formidable challenge. In South Africa, better knowledge of ‘fossilised’ Archean crustal sections ‘turned-on-edge’, such as at the Vredefort impact crater (for the continental crust), and from the Barberton greenstone belt (for oceanic crust) is needed to characterize potential pristine Archean Moho transitions.

  4. Bilateral angiosarcoma of the breast in a fourteen-year-old child.

    PubMed

    van Geel, Albertus N; den Bakker, Michael A

    2009-01-01

    Malignant vascular tumors are rare and angiosarcomas of the breast in patients under 21 years of age are exceedingly uncommon. In this report an angiosarcoma in the breast of a 14-year-old girl is described. She died nine months after mastectomy with recurrent disease in the bones and the contralateral breast. The etiology of most primary angiosarcomas is unknown. Secondary angiosarcomas can develop after radiotherapy and chronic lymphedema. The histology of this angiosarcoma is illustrated. PMID:21139917

  5. Fourteen Thousand Solar Systems and Growing: Results From the Starchitect Online Game at One Year

    NASA Astrophysics Data System (ADS)

    Harold, J. B.

    2015-12-01

    Starchitect (www.starchitect.net) is an online, end-to-end stellar and planetary evolution game designed to teach players about a variety of astronomy and planetary topics. Supported by NASA and NSF, and developed at the National Center for Interactive Learning at the Space Science Institute, the game uses the "sporadic play" model of games such as Farmville, where players might only take actions a few times a day, but continue playing for months. This framework is a natural fit for teaching about the evolution of stars and planets. Starchitect's systems evolve at a million years a minute, so that while massive stars will supernova almost immediately, lower mass stars like our sun will live for weeks of game time, possibly evolving life before passing through a red giant stage and ending their lives as white dwarfs. The game has now been live for over a year, playable both on Facebook and externally, and over 14,000 solar systems have been created by over 11,000 players. Since the game itself is heavily instrumented we now have access to a wealth of data that can be used to examine how people are playing the game and what tasks they are successfully engaging with. Through an embedded quiz game we are even in the position to assess the prior knowledge of our audience and execute pre/post assessments tied to game play. This paper will briefly describe the game and its educational strategies, then summarize some of our current results.

  6. Fourteen-year experience of prenatal diagnosis of thalassemia in Iran.

    PubMed

    Najmabadi, Hossein; Ghamari, Alireza; Sahebjam, Farhad; Kariminejad, Roxana; Hadavi, Valeh; Khatibi, Talayeh; Samavat, Ashraf; Mehdipour, Elaheh; Modell, Bernadette; Kariminejad, Mohammand Hassan

    2006-01-01

    For 14 years, Iranian scientists have worked to develop a national thalassemia prevention program. Although historically abortion was considered unacceptable in Iran, intensive consultations led to the clerical approval of induced abortion in cases with beta-thalassemia major in 1997, and a nationwide prevention program with screening, counseling and prenatal diagnosis (PND) networks has been developed. This paper reports the experience from one of the two national PND reference laboratories. As one of the oldest reference laboratories, we performed a total of 906 PND in 360 couples at risk for thalassemia from 1990 to 2003. Direct and indirect mutation detection methods were applied for all cases. In total, 22 mutations were tested routinely, and an additional 30 rare mutations were identified. 208 fetuses were found to be normal, 215 fetuses had beta-thalassemia major, and 435 fetuses were carriers of the trait. In 40 cases, we only defined one allele. In 8 cases, we were unable to provide any diagnosis, corresponding to 0.9%. Our data support the functionality of the Iranian beta-thalassemia prevention program. The success of this system in Iran, a multiethnic and Islamic-based country, would mean that it might be applied as an adaptive system for neighboring and other Islamic countries. PMID:16612059

  7. Fourteen years follow up after Lisfranc fracture-dislocation: functional and radiological results.

    PubMed

    Marín-Peña, Oliver R; Viloria Recio, Fernando; Sanz Gómez, Tomas; Larrainzar Garijo, Ricardo

    2012-12-01

    Injuries to the Lisfranc joint have a high potential for chronic disability. Posttraumatic arthritis remains the most common complication but not all patients who develop degenerative radiographic changes are symptomatic. A cohort of 32 patients with a Lisfranc fracture dislocation was reviewed. Initial reduction and secondary displacement were measured by the Myerson scale. Radiographic evidence of osteoarthritis (OA) was also investigated. Long-term radiographical data were classified as good, fair or poor results. Functional outcome was measured using several different scales. Mean follow up was 14 years. Seventeen patients with anatomic close reduction but instability were treated with closed reduction and K-wire fixation followed by cast immobilisation. Eight patients with stable anatomic close reduction were treated with closed reduction and cast. Seven patients with unacceptable closed reduction were treated with open reduction and K-wire stabilisation. The analysis of radiological long-term data showed 15 patients with good results, 8 with fair results and 9 with poor results. Final mean AOFAS score was 91.7/100. There was no statistically significant difference between overall PFS scores and different type of treatment, Hardcastle long-term radiological scores or Hardcastle type of fracture (p >0.05). Overall, there was a poor association between the extent of radiological arthritis and clinical scores. We advocate that for the evaluation of long-term outcome of these injuries functional parameters should be the focus of assessment, instead of radiological changes. PMID:23622999

  8. 1. Fourteen Years Of Diffuse CO2 Monitoring At Cerro Negro Volcano, Nicaragua

    NASA Astrophysics Data System (ADS)

    Barrancos Martinez, Jose; Melián, Gladys; Ibarra, Martha; Álvarez, Julio; Rodríguez, Fátima; Nolasco, Dácil; Padilla, Germán; Calvo, David; Dionis, Samara; Padrón, Eleazar; Hernández, Iñigo; Hernández, Pedro A.; Pérez, Nemesio M.; Muñoz, Angélica

    2013-04-01

    7. Cerro Negro is an active basaltic volcano belonging to the active Central American Volcanic Belt, which includes a 1,100 Km long chain of 41 active volcanoes from Guatemala to Panama. Cerro Negro first erupted in 1850 and has experienced 21 eruptive eruptions with inter eruptive average periods between 7 and 9 years. Since the last eruption occurred on 5 August 1999, with erupted lava flows and ash clouds together with gas emissions, a collaborative research program between INETER and ITER was established for monitoring diffuse CO2 emissions from this volcano. Until 2012, twelve soil CO2 emission surveys covering an area of 0,6 km2 have been performed by means of the accumulation chamber method to evaluate the spatial and temporal variations of CO2 degassing rate in relation to the eruptive cycle of Cerro Negro. A total diffuse CO2 emission output of 1,869 t•d-1 was estimated for the 1999 survey; just 3 months after the 1999 eruption which can be considered within the post-eruptive phase. For the April, 2002 and March, 2008 surveys, considered within the inter-eruptive phase, a clear decreasing tendency on the total diffuse CO2 output was observed, with estimates of 431 and 10 t•d-1, respectively, except a small increment in 2004, to 256 t d-1, associated with an anomalous seismic activity. The higher anomalies are located around the crater of 1995 and 1999. An increasing on the total CO2 emission has been observed, from December 2008 to February 2011, with total diffuse CO2 output estimates from 12 t•d-1 to 43 t•d-1, respectively. These temporal variations show a close relationship between diffuse CO2 emission and the eruptive cycle at Cerro Negro. This relationship indicates that monitoring CO2 emission is an important geochemical tool for the volcanic surveillance at Cerro Negro. References: (1) Rodríguez et al. (2009) AGU Fall Meeting 2009. EOS, AGU,V21-2017 . (2) Padilla et al. (2008). IV Reunión de la Red Española de Volcanología, Almagro 2008

  9. A SWIRE Picture is Worth Billions of Years

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: SWIRE View of Distant Galaxies [figure removed for brevity, see original site] [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 2Figure 3 Figure 4

    These spectacular images, taken by the Spitzer Wide-area Infrared Extragalactic (SWIRE) Legacy project, encapsulate one of the primary objectives of the Spitzer mission: to connect the evolution of galaxies from the distant, or early, universe to the nearby, or present day, universe.

    The Tadpole galaxy (main image) is the result of a recent galactic interaction in the local universe. Although these galactic mergers are rare in the universe's recent history, astronomers believe that they were much more common in the early universe. Thus, SWIRE team members will use this detailed image of the Tadpole galaxy to help understand the nature of the 'faint red-orange specks' of the early universe.

    The larger picture (figure 2) depicts one-sixteenth of the SWIRE survey field called ELAIS-N1. In this image, the bright blue sources are hot stars in our own Milky Way, which range anywhere from 3 to 60 times the mass of our Sun. The fainter green spots are cooler stars and galaxies beyond the Milky Way whose light is dominated by older stellar populations. The red dots are dusty galaxies that are undergoing intense star formation. The faintest specks of red-orange are galaxies billions of light-years away in the distant universe.

    Figure 3 features an unusual ring-like galaxy called CGCG 275-022. The red spiral arms indicate that this galaxy is very dusty and perhaps undergoing intense star formation. The star-forming activity could have been initiated by a near head-on collision with another galaxy.

    The most distant galaxies that SWIRE is able to detect are revealed in a zoom of deep space (figure 4). The colors in this feature represent the same objects as those in the larger field image of ELAIS

  10. Dynamics of Tree Species Composition in Temperate Mountains of South Korea over Fourteen Years using 880 Permanent Plots

    NASA Astrophysics Data System (ADS)

    Lee, B.; Kim, H. S.; Park, J.; Moon, M.; Cho, S.; Ryu, D.; Wynn, K. Z.; Park, J.

    2014-12-01

    The structure of forest and diversity of tree species in temperate mountains have been influenced by changing climate conditions as well as successional changes. To understand how tree species composition and stand structure change across temperate mountains, the species composition, size, and environmental information were collected over the past fourteen years in 880 quadrats of 20 m x 50 m of woodland communities distributed across Jiri and Baekoon Mountains, South Korea. The preliminary investigation on variations of tree species revealed that overall composition of tree species increased in terms of both diversity and biomass growth of tree species, reflecting fast and wide changes in temperate forests of Korea. Among dominant trees, the Quercus mongolica, Styrax japonicu, and Acer pseudosieboldianum recorded the highest increase in stand density, implying the most prosperous species under current conditions, while the species of Quercus variabilis and Fraxinus mandshurica appeared as fast declining species in the number. In terms of biomass growth of dominant species, the Stewartia pseudocamellia showed the largest increase of biomass, followed by Quercus serrata and Quercus mongolica., while the Fraxinus mandshurica appeared to have a rapid decline, followed by Alnus japonica and Quercus dentata. Overall, the fast change of composition in tree species is clear and further analysis to clarify the reasons for such fast and species-specific changes is underway especially to separate the effect of successional change and climate change.

  11. 3.4-Billion-year-old biogenic pyrites from Barberton, South Africa: sulfur isotope evidence

    NASA Technical Reports Server (NTRS)

    Ohmoto, H.; Kakegawa, T.; Lowe, D. R.

    1993-01-01

    Laser ablation mass spectroscopy analyses of sulfur isotopic compositions of microscopic-sized grains of pyrite that formed about 3.4 billion years ago in the Barberton Greenstone Belt, South Africa, show that the pyrite formed by bacterial reduction of seawater sulfate. These data imply that by about 3.4 billion years ago sulfate-reducing bacteria had become active, the oceans were rich in sulfate, and the atmosphere contained appreciable amounts (>>10(-13) of the present atmospheric level) of free oxygen.

  12. 3.4-Billion-year-old biogenic pyrites from Barberton, South Africa: sulfur isotope evidence.

    PubMed

    Ohmoto, H; Kakegawa, T; Lowe, D R

    1993-10-22

    Laser ablation mass spectroscopy analyses of sulfur isotopic compositions of microscopic-sized grains of pyrite that formed about 3.4 billion years ago in the Barberton Greenstone Belt, South Africa, show that the pyrite formed by bacterial reduction of seawater sulfate. These data imply that by about 3.4 billion years ago sulfate-reducing bacteria had become active, the oceans were rich in sulfate, and the atmosphere contained appreciable amounts (>10(-13) of the present atmospheric level) of free oxygen. PMID:11539502

  13. 3. 4-billion-year-old biogenic pyrites from Barberton, South Africa: Sulfur isotope evidence

    SciTech Connect

    Ohmoto, H.; Kakegawa, T. ); Lowe, D.R. )

    1993-10-22

    Laser ablation mass spectroscopy analysis of sulfur isotopic compositions of microscopic-sized grains of pyrite that formed about 3.4 billion years ago in the Barberton Greenstone Belt, South Africa, show that the pyrite formed by bacterial reduction of seawater sulfate. These data imply that by about 3.4 billion years ago sulfate-reducing bacteria had become active, the oceans were rich in sulfate, and the atmosphere contained appreciable amounts (> > 10[sup [minus]13] of the present atmospheric level) of free oxygen.

  14. Spatial variability in oceanic redox structure 1.8billion years ago

    NASA Astrophysics Data System (ADS)

    Poulton, Simon W.; Fralick, Philip W.; Canfield, Donald E.

    2010-07-01

    The evolution of ocean chemistry during the Proterozoic eon (2.5-0.542 billion years ago) is thought to have played a central role in both the timing and rate of eukaryote evolution. The timing of the deposition of iron formations implies that, early in the Earth's history, oceans were predominantly anoxic and rich in dissolved iron. However, global deposition of iron formations ceased about 1.84 billion years ago. This termination indicates a major upheaval in ocean chemistry, but the precise nature of this change remains debated. Here we use iron and sulphur systematics to reconstruct oceanic redox conditions from the 1.88- to 1.83-billion-year-old Animikie group from the Superior region, North America. We find that surface waters were oxygenated, whereas at mid-depths, anoxic and sulphidic (euxinic) conditions extended over 100km from the palaeoshoreline. The spatial extent of euxinia varied through time, but deep ocean waters remained rich in dissolved iron. Widespread euxinia along continental margins would have removed dissolved iron from the water column through the precipitation of pyrite, which would have reduced the supply of dissolved iron and resulted in the global cessation of the deposition of `Superior-type' iron formations. We suggest that incursions of sulphide from the mid-depths into overlying oxygenated surface waters may have placed severe constraints on eukaryotic evolution.

  15. The First Billion Years: The Growth of Galaxies in the Reionization Epoch

    NASA Astrophysics Data System (ADS)

    Illingworth, Garth

    2015-08-01

    Detection and measurement of the earliest galaxies in the first billion years only became possible after the Hubble Space Telescope was updated in 2009 with the infrared WFC3/IR camera during Shuttle servicing mission SM4. The first billion years is a fascinating epoch, not just because of the earliest galaxies known from about 450 Myr after the Big Bang, but also because it encompasses the reionization epoch that peaked around z~9, as Planck has recently shown, and ended around redshift z~6 at 900 Myr. Before 2009 just a handful of galaxies were known in the reionization epoch at z>6. But within the last 5 years, with the first HUDF09 survey, the HUDF12, CANDELS and numerous other surveys on the GOODS and CANDELS fields, as well as detections from the cluster lensing programs like CLASH and the Frontier Fields, the number of galaxies at redshifts 7-10 has exploded, with some 700 galaxies being found and characterized. The first billion years was a period of extraordinary growth in the galaxy population with rapid growth in the star formation rate density and global mass density in galaxies. Spitzer observations in the infrared of these Hubble fields are establishing masses as well as giving insights into the nature and timescales of star formation from the very powerful emission lines being revealed by the Spitzer IRAC data. I will discuss what we understand about the growth of galaxies in this epoch from the insights gained from remarkable deep fields like the XDF, as well as the wide-area GOODS/CANDELS fields, the detection of unexpectedly luminous galaxies at redshifts 8-10, the impact of early galaxies on reionization, confirmation of a number of galaxies at z~7-8 from ground-based spectroscopic measurements, and the indications of a change in the growth of the star formation rate around 500 Myr. The first billion years was a time of dramatic growth and change in the early galaxy population.

  16. Fourteen Years of Diverse Annual No-Till Cropping in Washington’s Winter Wheat – Summer Fallow Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have completed the 14th year of a cropping systems experiment to evaluate diverse annual (i.e., no summer fallow) cropping systems using no-till as an alternative to tillage-intensive winter wheat (Triticum aestivum L.) – summer fallow (WW-SF). Soft white and hard white classes of winter and spri...

  17. The Impact of Timing of Puberty on Psychosomatic Symptoms among Fourteen- to Sixteen-Year-Old Finnish Girls.

    ERIC Educational Resources Information Center

    Aro, Hillevi; Taipale, Vappu

    1987-01-01

    Studied whether pubertal age affects reports of psychosomatic symptoms among 14- to 16-year-old girls. Considered whether differences in dating and alcohol use might be mediating factors in the relation between pubertal age and psychosomatic symptoms. Subjects were 935 Finnish eighth-grade pupils who completed questionnaires three times during a…

  18. Electron microscopy reveals unique microfossil preservation in 1 billion-year-old lakes

    NASA Astrophysics Data System (ADS)

    Saunders, M.; Kong, C.; Menon, S.; Wacey, D.

    2014-06-01

    Electron microscopy was applied to the study of 1 billion-year-old microfossils from northwest Scotland in order to investigate their 3D morphology and mode of fossilization. 3D-FIB-SEM revealed high quality preservation of organic cell walls with only minor amounts of post-mortem decomposition, followed by variable degrees of morphological alteration (folding and compression of cell walls) during sediment compaction. EFTEM mapping plus SAED revealed a diverse fossilizing mineral assemblage including K-rich clay, Fe-Mg-rich clay and calcium phosphate, with each mineral occupying specific microenvironments in proximity to carbonaceous microfossil cell walls.

  19. Triploblastic animals more than 1 billion years ago: trace fossil evidence from india

    PubMed

    Seilacher; Bose; Pfluger

    1998-10-01

    Some intriguing bedding plane features that were observed in the Mesoproterozoic Chorhat Sandstone are biological and can be interpreted as the burrows of wormlike undermat miners (that is, infaunal animals that excavated tunnels underneath microbial mats). These burrows suggest that triploblastic animals existed more than a billion years ago. They also suggest that the diversification of animal designs proceeded very slowly before the appearance of organisms with hard skeletons, which was probably the key event in the Cambrian evolutionary explosion, and before the ecological changes that accompanied that event. PMID:9756480

  20. Fourteen Years of Pond Monitoring in Boreal Plain, northern Alberta, Canada: The effects of climate variability and harvesting practices

    NASA Astrophysics Data System (ADS)

    Abnizova, A.; Devito, K. J.; Petrone, R. M.

    2013-12-01

    Western Boreal forest of Canada is experiencing rapid increase in rates of cumulative impacts of disturbance for resource extraction, climate change and forest fires. To understand their sensitivity and response to multi-decadal natural and anthropogenic disturbances a long-term (1998-2013) and extensive pond ecosystem monitoring has been conducted on the Boreal Plains at the Utikuma Region Study Area (URSA) (56o N, 115o W). Hydrological, chemical and nutrient data were collected along a forest-peatland-pond transect in a paired catchment aspen harvest study in the area underlain by fine-grained till moraines glacial deposits. The aims of this study were (1) to identify the main characteristics in pond hydrologic regime, specifically water level dynamics, both seasonally and between years; (2) to identify factors controlling variation in measured hydro-chemistry and nutrients; and (3) to provide evidence on how water quality conditions in the ponds are changing on long (multi-year to decadal) time scales in response to harvesting practices and climatic trends during wet and dry cycles. No difference in pond or catchment hydrologic and hydro-chemical response was observed between harvested and reference sites pre- or post- harvesting. Wetland and pond waters were not affected by the harvesting practices due to lack of hydrologic connectivity between pond and forest systems. The hydrologic relationship between forestlands and open-water wetlands is a response in their water balance differences driven by their storage characteristics. Temporal trends in ponds' water levels, chemical and nutrient concentrations during the 14 year record were most closely related to relative connectivity to groundwater systems and flow direction in response to climatic cycles and vegetation water use and were the most useful parameters for characterizing duration and type of connectivity during wet and dry cycles. Using empirical relationships from such long-term monitoring, this study

  1. The evolution in the stellar mass of brightest cluster galaxies over the past 10 billion years

    NASA Astrophysics Data System (ADS)

    Bellstedt, Sabine; Lidman, Chris; Muzzin, Adam; Franx, Marijn; Guatelli, Susanna; Hill, Allison R.; Hoekstra, Henk; Kurinsky, Noah; Labbe, Ivo; Marchesini, Danilo; Marsan, Z. Cemile; Safavi-Naeini, Mitra; Sifón, Cristóbal; Stefanon, Mauro; van de Sande, Jesse; van Dokkum, Pieter; Weigel, Catherine

    2016-08-01

    Using a sample of 98 galaxy clusters recently imaged in the near infra-red with the ESO NTT, WIYN and WHT telescopes, supplemented with 33 clusters from the ESO archive, we measure how the stellar mass of the most massive galaxies in the universe, namely Brightest Cluster Galaxies (BCG), increases with time. Most of the BCGs in this new sample lie in the redshift range $0.2billion years ago to the present epoch is broadly consistent with recent semi-analytic and semi-empirical models. As in other recent studies, tentative evidence indicates that the stellar mass growth rate of BCGs may be slowing in the past 3.5 billion years. Further work in collecting larger samples, and in better comparing observations with theory using mock images is required if a more detailed comparison between the models and the data is to be made.

  2. The evolution in the stellar mass of Brightest Cluster Galaxies over the past 10 billion years

    NASA Astrophysics Data System (ADS)

    Bellstedt, Sabine; Lidman, Chris; Muzzin, Adam; Franx, Marijn; Guatelli, Susanna; Hill, Allison R.; Hoekstra, Henk; Kurinsky, Noah; Labbe, Ivo; Marchesini, Danilo; Marsan, Z. Cemile; Safavi-Naeini, Mitra; Sifón, Cristóbal; Stefanon, Mauro; van de Sande, Jesse; van Dokkum, Pieter; Weigel, Catherine

    2016-05-01

    Using a sample of 98 galaxy clusters recently imaged in the near infra-red with the ESO NTT, WIYN and WHT telescopes, supplemented with 33 clusters from the ESO archive, we measure how the stellar mass of the most massive galaxies in the universe, namely Brightest Cluster Galaxies (BCG), increases with time. Most of the BCGs in this new sample lie in the redshift range 0.2 < z < 0.6, which has been noted in recent works to mark an epoch over which the growth in the stellar mass of BCGs stalls. From this sample of 132 clusters, we create a subsample of 102 systems that includes only those clusters that have estimates of the cluster mass. We combine the BCGs in this subsample with BCGs from the literature, and find that the growth in stellar mass of BCGs from 10 billion years ago to the present epoch is broadly consistent with recent semi-analytic and semi-empirical models. As in other recent studies, tentative evidence indicates that the stellar mass growth rate of BCGs may be slowing in the past 3.5 billion years. Further work in collecting larger samples, and in better comparing observations with theory using mock images is required if a more detailed comparison between the models and the data is to be made.

  3. A massive galaxy in its core formation phase three billion years after the Big Bang.

    PubMed

    Nelson, Erica; van Dokkum, Pieter; Franx, Marijn; Brammer, Gabriel; Momcheva, Ivelina; Schreiber, Natascha Förster; da Cunha, Elisabete; Tacconi, Linda; Bezanson, Rachel; Kirkpatrick, Allison; Leja, Joel; Rix, Hans-Walter; Skelton, Rosalind; van der Wel, Arjen; Whitaker, Katherine; Wuyts, Stijn

    2014-09-18

    Most massive galaxies are thought to have formed their dense stellar cores in early cosmic epochs. Previous studies have found galaxies with high gas velocity dispersions or small apparent sizes, but so far no objects have been identified with both the stellar structure and the gas dynamics of a forming core. Here we report a candidate core in the process of formation 11 billion years ago, at redshift z = 2.3. This galaxy, GOODS-N-774, has a stellar mass of 100 billion solar masses, a half-light radius of 1.0 kiloparsecs and a star formation rate of solar masses per year. The star-forming gas has a velocity dispersion of 317 ± 30 kilometres per second. This is similar to the stellar velocity dispersions of the putative descendants of GOODS-N-774, which are compact quiescent galaxies at z ≈ 2 (refs 8-11) and giant elliptical galaxies in the nearby Universe. Galaxies such as GOODS-N-774 seem to be rare; however, from the star formation rate and size of this galaxy we infer that many star-forming cores may be heavily obscured, and could be missed in optical and near-infrared surveys. PMID:25162527

  4. The evolution in the stellar mass of brightest cluster galaxies over the past 10 billion years

    NASA Astrophysics Data System (ADS)

    Bellstedt, Sabine; Lidman, Chris; Muzzin, Adam; Franx, Marijn; Guatelli, Susanna; Hill, Allison R.; Hoekstra, Henk; Kurinsky, Noah; Labbe, Ivo; Marchesini, Danilo; Marsan, Z. Cemile; Safavi-Naeini, Mitra; Sifón, Cristóbal; Stefanon, Mauro; van de Sande, Jesse; van Dokkum, Pieter; Weigel, Catherine

    2016-08-01

    Using a sample of 98 galaxy clusters recently imaged in the near-infrared with the European Southern Observatory (ESO) New Technology Telescope, WIYN telescope and William Herschel Telescope, supplemented with 33 clusters from the ESO archive, we measure how the stellar mass of the most massive galaxies in the universe, namely brightest cluster galaxies (BCGs), increases with time. Most of the BCGs in this new sample lie in the redshift range 0.2 < z < 0.6, which has been noted in recent works to mark an epoch over which the growth in the stellar mass of BCGs stalls. From this sample of 132 clusters, we create a subsample of 102 systems that includes only those clusters that have estimates of the cluster mass. We combine the BCGs in this subsample with BCGs from the literature, and find that the growth in stellar mass of BCGs from 10 billion years ago to the present epoch is broadly consistent with recent semi-analytic and semi-empirical models. As in other recent studies, tentative evidence indicates that the stellar mass growth rate of BCGs may be slowing in the past 3.5 billion years. Further work in collecting larger samples, and in better comparing observations with theory using mock images, is required if a more detailed comparison between the models and the data is to be made.

  5. States' Spending on Colleges Rises 19 Pct. in 2 Years, Nears $31-Billion for'85-86.

    ERIC Educational Resources Information Center

    Evangelauf, Jean

    1985-01-01

    The U.S. states' expenditures to nearly $31 billion in tax money mark a continuing recovery in support for higher education. Shaping this year's appropriations levels were concerns about tuition and efforts to promote economic development. (MLW)

  6. Missing billions.

    PubMed

    Conly, S

    1997-01-01

    This article discusses funding of population programs that support the Cairo International Conference on Population and Development's Plan of Action. The Plan of Action calls for a quadrupling of annual financial commitments for population programs to $17 billion by the year 2000 and $22 billion by 2015. The increased expenditures would cover the increased demand for services from unmet need and population growth. Donor countries are expected to increase their share from the current 25% to about 33%, or $5.7 billion by the year 2000. The estimates are in 1993 constant dollars. $17 billion is less than the $40 billion that is spent worldwide on playing golf. During 1993-94, general donor support increased to $1.2 billion. Denmark, Germany, Japan, the Netherlands, the United Kingdom, and the United States increased their support. The United States doubled its support for population programs during 1992-95 to $583 million. During 1996-97 the US Congress cut funding back to the 1995 level. France, Italy, Spain, Belgium, and Austria have lagged in support for population programs in the present and the past. Equal burden sharing would require the US to increase funding to $1.9 billion. Developed country assistance declined to the lowest share of combined gross national product since 1970. This shifts the burden to multilateral sources. The European Union is committed to increasing its funding, and the World Bank increased funding for population and reproductive health to about $600 million in 1996 from $424 million in 1994. Bangladesh, China, India, Indonesia, Mexico, South Africa, and Turkey spent 85% of all government expenditures on family planning in developing countries. External donors in Africa are the main support of family planning. Private consumers in Latin America pay most of the costs of family planning. External assistance will be needed for some time. PMID:12321013

  7. Extraterrestrial demise of banded iron formations 1.85 billion years ago

    USGS Publications Warehouse

    Slack, J.F.; Cannon, W.F.

    2009-01-01

    In the Lake Superior region of North America, deposition of most banded iron formations (BIFs) ended abruptly 1.85 Ga ago, coincident with the oceanic impact of the giant Sudbury extraterrestrial bolide. We propose a new model in which this impact produced global mixing of shallow oxic and deep anoxic waters of the Paleoproterozoic ocean, creating a suboxic redox state for deep seawater. This suboxic state, characterized by only small concentrations of dissolved O2 (???1 ??M), prevented transport of hydrothermally derived Fe(II) from the deep ocean to continental-margin settings, ending an ???1.1 billion-year-long period of episodic BIF mineralization. The model is supported by the nature of Precambrian deep-water exhalative chemical sediments, which changed from predominantly sulfide facies prior to ca. 1.85 Ga to mainly oxide facies thereafter. ?? 2009 Geological Society of America.

  8. Star Formation in Galaxy Clusters Over the Past 10 Billion Years

    NASA Astrophysics Data System (ADS)

    Tran, Kim-Vy

    2012-01-01

    Galaxy clusters are the largest gravitationally bound systems in the universe and include the most massive galaxies in the universe; this makes galaxy clusters ideal laboratories for disentangling the nature versus nurture aspect of how galaxies evolve. Understanding how galaxies form and evolve in clusters continues to be a fundamental question in astronomy. The ages and assembly histories of galaxies in rich clusters test both stellar population models and hierarchical formation scenarios. Is star formation in cluster galaxies simply accelerated relative to their counterparts in the lower density field, or do cluster galaxies assemble their stars in a fundamentally different manner? To answer this question, I review multi-wavelength results on star formation in galaxy clusters from Coma to the most distant clusters yet discovered at look-back times of 10 billion years (z 2).

  9. A change in the geodynamics of continental growth 3 billion years ago.

    PubMed

    Dhuime, Bruno; Hawkesworth, Chris J; Cawood, Peter A; Storey, Craig D

    2012-03-16

    Models for the growth of continental crust rely on knowing the balance between the generation of new crust and the reworking of old crust throughout Earth's history. The oxygen isotopic composition of zircons, for which uranium-lead and hafnium isotopic data provide age constraints, is a key archive of crustal reworking. We identified systematic variations in hafnium and oxygen isotopes in zircons of different ages that reveal the relative proportions of reworked crust and of new crust through time. Growth of continental crust appears to have been a continuous process, albeit at variable rates. A marked decrease in the rate of crustal growth at ~3 billion years ago may be linked to the onset of subduction-driven plate tectonics. PMID:22422979

  10. Geodynamo, solar wind, and magnetopause 3.4 to 3.45 billion years ago.

    PubMed

    Tarduno, John A; Cottrell, Rory D; Watkeys, Michael K; Hofmann, Axel; Doubrovine, Pavel V; Mamajek, Eric E; Liu, Dunji; Sibeck, David G; Neukirch, Levi P; Usui, Yoichi

    2010-03-01

    Stellar wind standoff by a planetary magnetic field prevents atmospheric erosion and water loss. Although the early Earth retained its water and atmosphere, and thus evolved as a habitable planet, little is known about Earth's magnetic field strength during that time. We report paleointensity results from single silicate crystals bearing magnetic inclusions that record a geodynamo 3.4 to 3.45 billion years ago. The measured field strength is approximately 50 to 70% that of the present-day field. When combined with a greater Paleoarchean solar wind pressure, the paleofield strength data suggest steady-state magnetopause standoff distances of < or = 5 Earth radii, similar to values observed during recent coronal mass ejection events. The data also suggest lower-latitude aurora and increases in polar cap area, as well as heating, expansion, and volatile loss from the exosphere that would have affected long-term atmospheric composition. PMID:20203044

  11. Atmospheric carbon dioxide: a driver of photosynthetic eukaryote evolution for over a billion years?

    PubMed Central

    Beerling, David J.

    2012-01-01

    Exciting evidence from diverse fields, including physiology, evolutionary biology, palaeontology, geosciences and molecular genetics, is providing an increasingly secure basis for robustly formulating and evaluating hypotheses concerning the role of atmospheric carbon dioxide (CO2) in the evolution of photosynthetic eukaryotes. Such studies span over a billion years of evolutionary change, from the origins of eukaryotic algae through to the evolution of our present-day terrestrial floras, and have relevance for plant and ecosystem responses to future global CO2 increases. The papers in this issue reflect the breadth and depth of approaches being adopted to address this issue. They reveal new discoveries pointing to deep evidence for the role of CO2 in shaping evolutionary changes in plants and ecosystems, and establish an exciting cross-disciplinary research agenda for uncovering new insights into feedbacks between biology and the Earth system. PMID:22232760

  12. IRON AND {alpha}-ELEMENT PRODUCTION IN THE FIRST ONE BILLION YEARS AFTER THE BIG BANG

    SciTech Connect

    Becker, George D.; Carswell, Robert F.; Sargent, Wallace L. W.; Rauch, Michael E-mail: acalver@ast.cam.ac.uk E-mail: mr@obs.carnegiescience.edu

    2012-01-10

    We present measurements of carbon, oxygen, silicon, and iron in quasar absorption systems existing when the universe was roughly one billion years old. We measure column densities in nine low-ionization systems at 4.7 < z < 6.3 using Keck, Magellan, and Very Large Telescope optical and near-infrared spectra with moderate to high resolution. The column density ratios among C II, O I, Si II, and Fe II are nearly identical to sub-damped Ly{alpha} systems (sub-DLAs) and metal-poor ([M/H] {<=} -1) DLAs at lower redshifts, with no significant evolution over 2 {approx}< z {approx}< 6. The estimated intrinsic scatter in the ratio of any two elements is also small, with a typical rms deviation of {approx}< 0.1 dex. These facts suggest that dust depletion and ionization effects are minimal in our z > 4.7 systems, as in the lower-redshift DLAs, and that the column density ratios are close to the intrinsic relative element abundances. The abundances in our z > 4.7 systems are therefore likely to represent the typical integrated yields from stellar populations within the first gigayear of cosmic history. Due to the time limit imposed by the age of the universe at these redshifts, our measurements thus place direct constraints on the metal production of massive stars, including iron yields of prompt supernovae. The lack of redshift evolution further suggests that the metal inventories of most metal-poor absorption systems at z {approx}> 2 are also dominated by massive stars, with minimal contributions from delayed Type Ia supernovae or winds from asymptotic giant branch stars. The relative abundances in our systems broadly agree with those in very metal-poor, non-carbon-enhanced Galactic halo stars. This is consistent with the picture in which present-day metal-poor stars were potentially formed as early as one billion years after the big bang.

  13. An anoxic, Fe(II)-rich, U-poor ocean 3.46 billion years ago

    NASA Astrophysics Data System (ADS)

    Li, Weiqiang; Czaja, Andrew D.; Van Kranendonk, Martin J.; Beard, Brian L.; Roden, Eric E.; Johnson, Clark M.

    2013-11-01

    The oxidation state of the atmosphere and oceans on the early Earth remains controversial. Although it is accepted by many workers that the Archean atmosphere and ocean were anoxic, hematite in the 3.46 billion-year-old (Ga) Marble Bar Chert (MBC) from Pilbara Craton, NW Australia has figured prominently in arguments that the Paleoarchean atmosphere and ocean was fully oxygenated. In this study, we report the Fe isotope compositions and U concentrations of the MBC, and show that the samples have extreme heavy Fe isotope enrichment, where δ56Fe values range between +1.5‰ and +2.6‰, the highest δ56Fe values for bulk samples yet reported. The high δ56Fe values of the MBC require very low levels of oxidation and, in addition, point to a Paleoarchean ocean that had high aqueous Fe(II) contents. A dispersion/reaction model indicates that O2 contents in the photic zone of the ocean were less than 10-3 μM, which suggests that the ocean was essentially anoxic. An independent test of anoxic conditions is provided by U-Th-Pb isotope systematics, which show that U contents in the Paleoarchean ocean were likely below 0.02 ppb, two orders-of-magnitude lower than the modern ocean. Collectively, the Fe and U data indicate a reduced, Fe(II)-rich, U-poor environment in the Archean oceans at 3.46 billion years ago. Given the evidence for photosynthetic communities provided by broadly coeval stromatolites, these results suggests that an important photosynthetic pathway in the Paleoarchean oceans may have been anoxygenic photosynthetic Fe(II) oxidation.

  14. 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.

  15. Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone

    NASA Astrophysics Data System (ADS)

    Lowenstern, J. B.; Evans, W. C.; Bergfeld, D.; Hunt, A. G.

    2014-02-01

    Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the rise of continents. The hydrothermal system at Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio, commonly cited as evidence for a deep mantle source for the Yellowstone hotspot. However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by α-decay of uranium and thorium. Here we show, by combining gas emission rates with chemistry and isotopic analyses, that crustal helium-4 emission rates from Yellowstone exceed (by orders of magnitude) any conceivable rate of generation within the crust. It seems that helium has accumulated for (at least) many hundreds of millions of years in Archaean (more than 2.5 billion years old) cratonic rocks beneath Yellowstone, only to be liberated over the past two million years by intense crustal metamorphism induced by the Yellowstone hotspot. Our results demonstrate the extremes in variability of crustal helium efflux on geologic timescales and imply crustal-scale open-system behaviour of helium in tectonically and magmatically active regions.

  16. Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone

    USGS Publications Warehouse

    Lowenstern, Jacob B.; Evans, William C.; Bergfeld, D.; Hunt, Andrew G.

    2014-01-01

    Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the rise of continents1. The hydrothermal system at Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio, commonly cited as evidence for a deep mantle source for the Yellowstone hotspot2. However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by α-decay of uranium and thorium. Here we show, by combining gas emission rates with chemistry and isotopic analyses, that crustal helium-4 emission rates from Yellowstone exceed (by orders of magnitude) any conceivable rate of generation within the crust. It seems that helium has accumulated for (at least) many hundreds of millions of years in Archaean (more than 2.5 billion years old) cratonic rocks beneath Yellowstone, only to be liberated over the past two million years by intense crustal metamorphism induced by the Yellowstone hotspot. Our results demonstrate the extremes in variability of crustal helium efflux on geologic timescales and imply crustal-scale open-system behaviour of helium in tectonically and magmatically active regions.

  17. Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone.

    PubMed

    Lowenstern, J B; Evans, W C; Bergfeld, D; Hunt, A G

    2014-02-20

    Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the rise of continents. The hydrothermal system at Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio, commonly cited as evidence for a deep mantle source for the Yellowstone hotspot. However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by α-decay of uranium and thorium. Here we show, by combining gas emission rates with chemistry and isotopic analyses, that crustal helium-4 emission rates from Yellowstone exceed (by orders of magnitude) any conceivable rate of generation within the crust. It seems that helium has accumulated for (at least) many hundreds of millions of years in Archaean (more than 2.5 billion years old) cratonic rocks beneath Yellowstone, only to be liberated over the past two million years by intense crustal metamorphism induced by the Yellowstone hotspot. Our results demonstrate the extremes in variability of crustal helium efflux on geologic timescales and imply crustal-scale open-system behaviour of helium in tectonically and magmatically active regions. PMID:24553240

  18. Galaxy evolution. Evidence for mature bulges and an inside-out quenching phase 3 billion years after the Big Bang.

    PubMed

    Tacchella, S; Carollo, C M; Renzini, A; Förster Schreiber, N M; Lang, P; Wuyts, S; Cresci, G; Dekel, A; Genzel, R; Lilly, S J; Mancini, C; Newman, S; Onodera, M; Shapley, A; Tacconi, L; Woo, J; Zamorani, G

    2015-04-17

    Most present-day galaxies with stellar masses ≥10(11) solar masses show no ongoing star formation and are dense spheroids. Ten billion years ago, similarly massive galaxies were typically forming stars at rates of hundreds solar masses per year. It is debated how star formation ceased, on which time scales, and how this "quenching" relates to the emergence of dense spheroids. We measured stellar mass and star-formation rate surface density distributions in star-forming galaxies at redshift 2.2 with ~1-kiloparsec resolution. We find that, in the most massive galaxies, star formation is quenched from the inside out, on time scales less than 1 billion years in the inner regions, up to a few billion years in the outer disks. These galaxies sustain high star-formation activity at large radii, while hosting fully grown and already quenched bulges in their cores. PMID:25883353

  19. Cooling and exhumation of continents at billion-year time scales

    NASA Astrophysics Data System (ADS)

    Blackburn, T.; Bowring, S. A.; Perron, T.; Mahan, K. H.; Dudas, F. O.

    2011-12-01

    The oldest rocks on Earth are preserved within the continental lithosphere, where assembled fragments of ancient orogenic belts have survived erosion and destruction by plate tectonic and surface processes for billions of years. Though the rate of orogenic exhumation and erosion has been measured for segments of an orogenic history, it remains unclear how these exhumation rates have changed over the lifetime of any terrane. Because the exhumation of the lithospheric surface has a direct effect on the rate of heat loss within the lithosphere, a continuous record of lithosphere exhumation can be reconstructed through the use of thermochronology. Thermochronologic studies have typically employed systems sensitive to cooling at temperatures <300 °C, such as the (U-Th)/He and 40Ar/39Ar systems. This largely restricts their application to measuring cooling in rocks from the outer 10 km of the Earth's crust, resulting in a thermal history that is controlled by either upper crustal flexure and faulting and/or isotherm inflections related to surface topography. Combining these biases with the uplift, erosion and recycling of these shallow rocks results in a poor preservation potential of any long-term record. Here, an ancient and long-term record of lithosphere exhumation is constructed using U-Pb thermochronology, a geochronologic system sensitive to cooling at temperatures found at 20-50 km depth (400-650 °C). Lower crustal xenoliths provide material that resided at these depths for billions of years or more, recording a thermal history that is buried deep enough to remain insensitive to upper crustal deformation and instead is dominated by the vertical motions of the continents. We show how this temperature-sensitive system can produce a long-term integrated measure of continental exhumation and erosion. Preserved beneath Phanerozoic sedimentary rocks within Montana, USA, the Great Falls Tectonic Zone formed when two Archean cratons, the Wyoming Province and Medicine

  20. Rapid oxygenation of Earth's atmosphere 2.33 billion years ago.

    PubMed

    Luo, Genming; Ono, Shuhei; Beukes, Nicolas J; Wang, David T; Xie, Shucheng; Summons, Roger E

    2016-05-01

    Molecular oxygen (O2) is, and has been, a primary driver of biological evolution and shapes the contemporary landscape of Earth's biogeochemical cycles. Although "whiffs" of oxygen have been documented in the Archean atmosphere, substantial O2 did not accumulate irreversibly until the Early Paleoproterozoic, during what has been termed the Great Oxygenation Event (GOE). The timing of the GOE and the rate at which this oxygenation took place have been poorly constrained until now. We report the transition (that is, from being mass-independent to becoming mass-dependent) in multiple sulfur isotope signals of diagenetic pyrite in a continuous sedimentary sequence in three coeval drill cores in the Transvaal Supergroup, South Africa. These data precisely constrain the GOE to 2.33 billion years ago. The new data suggest that the oxygenation occurred rapidly-within 1 to 10 million years-and was followed by a slower rise in the ocean sulfate inventory. Our data indicate that a climate perturbation predated the GOE, whereas the relationships among GOE, "Snowball Earth" glaciation, and biogeochemical cycling will require further stratigraphic correlation supported with precise chronologies and paleolatitude reconstructions. PMID:27386544

  1. Half a billion years of good weather: Gaia or good luck?

    NASA Astrophysics Data System (ADS)

    Waltham, Dave

    2007-06-01

    For the past 550 million years, Earth has had a relatively stable climate, with average global temperatures generally fluctuating by less than 10°C from the present value of around 15°C. In the preceding 4 billion years, temperature fluctuations were almost an order of magnitude greater. One explanation for climate stability is that the biosphere evolves to maintain optimum conditions for life (the Gaia hypothesis). But this stability could also result from luck and, without such good fortune, conditions on Earth would have been unsuitable for the evolution of complex life: anthropic selection, in other words. One element of such good luck concerns the climatic impact of the Moon; the properties of the Earth-Moon system only just allow a stable rotation axis for the Earth (considered a prerequisite for climate stability and the evolution of complex life). Axial stability also requires Jupiter and Saturn to be widely spaced, offering a test of the rarity or otherwise of the solar system arrangement among exoplanet systems. Gravitational microlensing surveys should allow this to be tested within a decade.

  2. Constraints on the first billion years of the geodynamo from paleointensity studies of zircons

    NASA Astrophysics Data System (ADS)

    Tarduno, John; Cottrell, Rory; Davis, William

    2014-05-01

    Several lines of reasoning, including new ideas on core thermal conductivity, suggest that onset of a strong geomagnetic field might have been delayed by one billion years (or more) after the lunar forming event. Here we extend the Proterozoic/Archean to Paleoarchean record of the geomagnetic field constrained by single crystal paleointensity (SCP) analyses (Tarduno et al., Science, 2010) to older times using zircons containing minute magnetic inclusions. Specifically, we focus on samples from the Jack Hills (Yilgarn Craton, Western Australia). We employ a CO2 laser demagnetization system and a small bore (6.3 mm) 3-component DC SQUID magnetometer; the latter offers the highest currently available moment resolution. Sample age is analyzed using SHRIMP U-Pb geochronology. Preliminary data support the presence of a relatively strong Paleoarchean field produced by a core dynamo, extending the known record by at least 100 million years, to approximately 3.55 Ga. These data only serve to exacerbate the apparent problem posed by the presence of a Paleoarchean dynamo. Alternative dynamo driving mechanisms, or efficient core/lowermost mantle heat loss processes unique to the Paleoarchean (and older times) might have been at work. We will discuss these processes, and our efforts to study even older Eoarchean-Hadean zircons.

  3. A redox-stratified ocean 3.2 billion years ago

    NASA Astrophysics Data System (ADS)

    Satkoski, Aaron M.; Beukes, Nicolas J.; Li, Weiqiang; Beard, Brian L.; Johnson, Clark M.

    2015-11-01

    Before the Great Oxidation Event (GOE) 2.4-2.2 billion years ago it has been traditionally thought that oceanic water columns were uniformly anoxic due to a lack of oxygen-producing microorganisms. Recently, however, it has been proposed that transient oxygenation of shallow seawater occurred between 2.8 and 3.0 billion years ago. Here, we present a novel combination of stable Fe and radiogenic U-Th-Pb isotope data that demonstrate significant oxygen contents in the shallow oceans at 3.2 Ga, based on analysis of the Manzimnyama Banded Iron Formation (BIF), Fig Tree Group, South Africa. This unit is exceptional in that proximal, shallow-water and distal, deep-water facies are preserved. When compared to the distal, deep-water facies, the proximal samples show elevated U concentrations and moderately positive δ56Fe values, indicating vertical stratification in dissolved oxygen contents. Confirmation of oxidizing conditions using U abundances is robustly constrained using samples that have been closed to U and Pb mobility using U-Th-Pb geochronology. Although redox-sensitive elements have been commonly used in ancient rocks to infer redox conditions, post-depositional element mobility has been rarely tested, and U-Th-Pb geochronology can constrain open- or closed-system behavior. The U abundances and δ56Fe values of the Manzimnyama BIF suggest the proximal, shallow-water samples record precipitation under stronger oxidizing conditions compared to the distal deeper-water facies, which in turn indicates the existence of a discrete redox boundary between deep and shallow ocean waters at this time; this work, therefore, documents the oldest known preserved marine redox gradient in the rock record. The relative enrichment of O2 in the upper water column is likely due to the existence of oxygen-producing microorganisms such as cyanobacteria. These results provide a new approach for identifying free oxygen in Earth's ancient oceans, including confirming the age of redox

  4. The Star Formation History of the Universe over the Past Eight Billion Years

    NASA Astrophysics Data System (ADS)

    Zhu, Guangtun

    How galaxies such as our own Milky Way formed and evolved remains a mystery. There are two general approaches in galaxy formation and evolution studies. One is to infer formation histories via archaeological investigations of galaxies at low redshift, in the local Universe. The other is to study galaxy formation and evolution in action by observing faint distant galaxies, the ancestors of local galaxies, in the more distant and younger Universe, at higher redshift. I employ the first approach to study the formation of elliptical galaxies, the most massive galaxies in the Universe. I investigate the stellar content of 1923 elliptical galaxies, the largest high-fidelity sample in the local Universe, as a function of stellar mass and environment. I infer their star formation histories, finding that isolated low-mass elliptical galaxies formed their stars slightly later than their counterparts in galaxy clusters. I measure the cosmic star formation rate (SFR) density at redshift z ˜ 1, when the Universe was eight billion years younger. The cosmic SFR density measures how many stars are being formed per unit volume of the Universe. I show that galaxies were more actively forming stars eight billion years ago than they are at present, by roughly an order of magnitude. The reason why galaxies are so much less active at present remains unknown, partly due to the small sample size of distant galaxies observed previously. To improve the sample size, we have completed a new galaxy survey, the Prism Multi-object Survey (PRIMUS). We have observed ˜ 120, 000 galaxies spanning distances from the local Universe to redshift z ˜ 1. We specifically targeted fields with existing multi-wavelength data in the X-ray, ultraviolet, optical, and infrared. The large sample and multi-wavelength data allow precise statistical studies of galaxy evolution since z ˜1. As a preliminary result from PRIMUS, I show that 15% of galaxies that appear to lack star formation in the optical actually

  5. The First Billion Years project: dark matter haloes going from contraction to expansion and back again

    NASA Astrophysics Data System (ADS)

    Davis, Andrew J.; Khochfar, Sadegh; Dalla Vecchia, Claudio

    2014-09-01

    We study the effect of baryons on the inner dark matter profile of the first galaxies using the First Billion Years simulation between z = 16 and 6 before secular evolution sets in. Using a large statistical sample from two simulations of the same volume and cosmological initial conditions, one with and one without baryons, we are able to directly compare haloes with their baryon-free counterparts, allowing a detailed study of the modifications to the dark matter density profile due to the presence of baryons during the first billion years of galaxy formation. For each of the ≈5000 haloes in our sample (3 × 107 M⊙ ≤ Mtot ≤ 5 × 109 M⊙), we quantify the impact of the baryons using η, defined as the ratio of dark matter mass enclosed in 100 pc in the baryonic run to its counterpart without baryons. During this epoch of rapid growth of galaxies, we find that many haloes of these first galaxies show an enhancement of dark matter in the halo centre compared to the baryon-free simulation, while many others show a deficit. We find that the mean value of η is close to unity, but there is a large dispersion, with a standard deviation of 0.677. The enhancement is cyclical in time and tracks the star formation cycle of the galaxy; as gas falls to the centre and forms stars, the dark matter moves in as well. Supernova (SN) feedback then removes the gas, and the dark matter again responds to the changing potential. We study three physical models relating the motion of baryons to that of the dark matter: adiabatic contraction, dynamical friction, and rapid outflows. We find that dynamical friction plays only a very minor role, while adiabatic contraction and the rapid outflows due to feedback describe well the enhancement (or decrement) of dark matter. For haloes which show significant decrements of dark matter in the core, we find that to remove the dark matter requires an energy input between 1051 and 1053 erg. For our SN feedback proscription, this requires as a

  6. Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes.

    PubMed

    Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D

    2014-01-01

    Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments. PMID:25068404

  7. A large neutral fraction of cosmic hydrogen a billion years after the Big Bang.

    PubMed

    Wyithe, J Stuart B; Loeb, Abraham

    2004-02-26

    The fraction of ionized hydrogen left over from the Big Bang provides evidence for the time of formation of the first stars and quasar black holes in the early Universe; such objects provide the high-energy photons necessary to ionize hydrogen. Spectra of the two most distant known quasars show nearly complete absorption of photons with wavelengths shorter than the Lyman alpha transition of neutral hydrogen, indicating that hydrogen in the intergalactic medium (IGM) had not been completely ionized at a redshift of z approximately 6.3, about one billion years after the Big Bang. Here we show that the IGM surrounding these quasars had a neutral hydrogen fraction of tens of per cent before the quasar activity started, much higher than the previous lower limits of approximately 0.1 per cent. Our results, when combined with the recent inference of a large cumulative optical depth to electron scattering after cosmological recombination therefore suggest the presence of a second peak in the mean ionization history of the Universe. PMID:14985754

  8. Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon.

    PubMed

    Bell, Elizabeth A; Boehnke, Patrick; Harrison, T Mark; Mao, Wendy L

    2015-11-24

    Evidence of life on Earth is manifestly preserved in the rock record. However, the microfossil record only extends to ∼ 3.5 billion years (Ga), the chemofossil record arguably to ∼ 3.8 Ga, and the rock record to 4.0 Ga. Detrital zircons from Jack Hills, Western Australia range in age up to nearly 4.4 Ga. From a population of over 10,000 Jack Hills zircons, we identified one >3.8-Ga zircon that contains primary graphite inclusions. Here, we report carbon isotopic measurements on these inclusions in a concordant, 4.10 ± 0.01-Ga zircon. We interpret these inclusions as primary due to their enclosure in a crack-free host as shown by transmission X-ray microscopy and their crystal habit. Their δ(13)CPDB of -24 ± 5‰ is consistent with a biogenic origin and may be evidence that a terrestrial biosphere had emerged by 4.1 Ga, or ∼ 300 My earlier than has been previously proposed. PMID:26483481

  9. Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes

    NASA Astrophysics Data System (ADS)

    Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D.

    2014-07-01

    Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments.

  10. A Massive Galaxy in Its Core Formation Phase Three Billion Years After the Big Bang

    NASA Technical Reports Server (NTRS)

    Nelson, Erica; van Dokkum, Pieter; Franx, Marijn; Brammer, Gabriel; Momcheva, Ivelina; Schreiber, Natascha M. Forster; da Cunha, Elisabete; Tacconi, Linda; Bezanson, Rachel; Kirkpatrick, Allison; Leja, Joel; Rix, Hans-Walter; Skelton, Rosalind; van der Wel, Arjen; Whitaker, Katherine; Wuyts, Stijn

    2014-01-01

    Most massive galaxies are thought to have formed their dense stellar cores at early cosmic epochs. However, cores in their formation phase have not yet been observed. Previous studies have found galaxies with high gas velocity dispersions or small apparent sizes but so far no objects have been identified with both the stellar structure and the gas dynamics of a forming core. Here we present a candidate core in formation 11 billion years ago, at z = 2.3. GOODS-N-774 has a stellar mass of 1.0 × 10 (exp 11) solar mass, a half-light radius of 1.0 kpc, and a star formation rate of 90 (sup +45 / sub -20) solar mass/yr. The star forming gas has a velocity dispersion 317 plus or minus 30 km/s, amongst the highest ever measured. It is similar to the stellar velocity dispersions of the putative descendants of GOODS-N-774, compact quiescent galaxies at z is approximately equal to 2 (exp 8-11) and giant elliptical galaxies in the nearby Universe. Galaxies such as GOODS-N-774 appear to be rare; however, from the star formation rate and size of the galaxy we infer that many star forming cores may be heavily obscured, and could be missed in optical and near-infrared surveys.

  11. Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon

    PubMed Central

    Bell, Elizabeth A.; Harrison, T. Mark; Mao, Wendy L.

    2015-01-01

    Evidence of life on Earth is manifestly preserved in the rock record. However, the microfossil record only extends to ∼3.5 billion years (Ga), the chemofossil record arguably to ∼3.8 Ga, and the rock record to 4.0 Ga. Detrital zircons from Jack Hills, Western Australia range in age up to nearly 4.4 Ga. From a population of over 10,000 Jack Hills zircons, we identified one >3.8-Ga zircon that contains primary graphite inclusions. Here, we report carbon isotopic measurements on these inclusions in a concordant, 4.10 ± 0.01-Ga zircon. We interpret these inclusions as primary due to their enclosure in a crack-free host as shown by transmission X-ray microscopy and their crystal habit. Their δ13CPDB of −24 ± 5‰ is consistent with a biogenic origin and may be evidence that a terrestrial biosphere had emerged by 4.1 Ga, or ∼300 My earlier than has been previously proposed. PMID:26483481

  12. Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon

    DOE PAGESBeta

    Bell, Elizabeth A.; Boehnke, Patrick; Harrison, T. Mark; Mao, Wendy L.

    2015-10-19

    Here, evidence of life on Earth is manifestly preserved in the rock record. However, the microfossil record only extends to ~3.5 billion years (Ga), the chemofossil record arguably to ~3.8 Ga, and the rock record to 4.0 Ga. Detrital zircons from Jack Hills, Western Australia range in age up to nearly 4.4 Ga. From a population of over 10,000 Jack Hills zircons, we identified one >3.8-Ga zircon that contains primary graphite inclusions. Here, we report carbon isotopic measurements on these inclusions in a concordant, 4.10 ± 0.01-Ga zircon. We interpret these inclusions as primary due to their enclosure in amore » crack-free host as shown by transmission X-ray microscopy and their crystal habit. Their δ13CPDB of –24 ± 5‰ is consistent with a biogenic origin and may be evidence that a terrestrial biosphere had emerged by 4.1 Ga, or ~300 My earlier than has been previously proposed.« less

  13. Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon

    SciTech Connect

    Bell, Elizabeth A.; Boehnke, Patrick; Harrison, T. Mark; Mao, Wendy L.

    2015-10-19

    Here, evidence of life on Earth is manifestly preserved in the rock record. However, the microfossil record only extends to ~3.5 billion years (Ga), the chemofossil record arguably to ~3.8 Ga, and the rock record to 4.0 Ga. Detrital zircons from Jack Hills, Western Australia range in age up to nearly 4.4 Ga. From a population of over 10,000 Jack Hills zircons, we identified one >3.8-Ga zircon that contains primary graphite inclusions. Here, we report carbon isotopic measurements on these inclusions in a concordant, 4.10 ± 0.01-Ga zircon. We interpret these inclusions as primary due to their enclosure in a crack-free host as shown by transmission X-ray microscopy and their crystal habit. Their δ13CPDB of –24 ± 5‰ is consistent with a biogenic origin and may be evidence that a terrestrial biosphere had emerged by 4.1 Ga, or ~300 My earlier than has been previously proposed.

  14. Rapid oxygenation of Earth’s atmosphere 2.33 billion years ago

    PubMed Central

    Luo, Genming; Ono, Shuhei; Beukes, Nicolas J.; Wang, David T.; Xie, Shucheng; Summons, Roger E.

    2016-01-01

    Molecular oxygen (O2) is, and has been, a primary driver of biological evolution and shapes the contemporary landscape of Earth’s biogeochemical cycles. Although “whiffs” of oxygen have been documented in the Archean atmosphere, substantial O2 did not accumulate irreversibly until the Early Paleoproterozoic, during what has been termed the Great Oxygenation Event (GOE). The timing of the GOE and the rate at which this oxygenation took place have been poorly constrained until now. We report the transition (that is, from being mass-independent to becoming mass-dependent) in multiple sulfur isotope signals of diagenetic pyrite in a continuous sedimentary sequence in three coeval drill cores in the Transvaal Supergroup, South Africa. These data precisely constrain the GOE to 2.33 billion years ago. The new data suggest that the oxygenation occurred rapidly—within 1 to 10 million years—and was followed by a slower rise in the ocean sulfate inventory. Our data indicate that a climate perturbation predated the GOE, whereas the relationships among GOE, “Snowball Earth” glaciation, and biogeochemical cycling will require further stratigraphic correlation supported with precise chronologies and paleolatitude reconstructions. PMID:27386544

  15. A billion years of environmental stability and the emergence of eukaryotes: new data from northern Australia.

    PubMed

    Brasier, M D; Lindsay, J F

    1998-06-01

    Carbon isotopes through 6km of fully cored drill holes in 1.7 to 1.5 Ga carbonates of the Mount Isa and McArthur basins, Australia (which host the earliest known eukaryote biomarkers) provide the most comprehensive and best-dated delta 13C stratigraphy yet obtained from such ancient rocks. Both basins reveal remarkably stable temporal delta 13C trends (mean of -0.6% +/- 2% PDB [Peedee belemnite]) and confirm the impression of delta 13C stasis between 2.0 and 1.0 Ga, which, together with other evidence, suggest a prolonged period of stability in crustal dynamics, redox state of surface environments, and planetary climate. This delta 13C stasis is consistent with great stability in the carbon cycle controlled, we suggest, by P limitation of primary productivity. Recent evidence shows that P depletion is a major factor in obligate associations between photosymbionts and host cells. We argue that a billion years of stability in the carbon and nutrient cycles may have been the driving force that propelled prokaryotes toward photosymbiosis and the emergence of the autotrophic eukaryote cell. PMID:11541449

  16. The formation of submillimetre-bright galaxies from gas infall over a billion years.

    PubMed

    Narayanan, Desika; Turk, Matthew; Feldmann, Robert; Robitaille, Thomas; Hopkins, Philip; Thompson, Robert; Hayward, Christopher; Ball, David; Faucher-Giguère, Claude-André; Kereš, Dušan

    2015-09-24

    Submillimetre-bright galaxies at high redshift are the most luminous, heavily star-forming galaxies in the Universe and are characterized by prodigious emission in the far-infrared, with a flux of at least five millijanskys at a wavelength of 850 micrometres. They reside in haloes with masses about 10(13) times that of the Sun, have low gas fractions compared to main-sequence disks at a comparable redshift, trace complex environments and are not easily observable at optical wavelengths. Their physical origin remains unclear. Simulations have been able to form galaxies with the requisite luminosities, but have otherwise been unable to simultaneously match the stellar masses, star formation rates, gas fractions and environments. Here we report a cosmological hydrodynamic galaxy formation simulation that is able to form a submillimetre galaxy that simultaneously satisfies the broad range of observed physical constraints. We find that groups of galaxies residing in massive dark matter haloes have increasing rates of star formation that peak at collective rates of about 500-1,000 solar masses per year at redshifts of two to three, by which time the interstellar medium is sufficiently enriched with metals that the region may be observed as a submillimetre-selected system. The intense star formation rates are fuelled in part by the infall of a reservoir gas supply enabled by stellar feedback at earlier times, not through major mergers. With a lifetime of nearly a billion years, our simulations show that the submillimetre-bright phase of high-redshift galaxies is prolonged and associated with significant mass buildup in early-Universe proto-clusters, and that many submillimetre-bright galaxies are composed of numerous unresolved components (for which there is some observational evidence). PMID:26399829

  17. Searching for the birthplaces of open clusters with ages of several billion years

    NASA Astrophysics Data System (ADS)

    Acharova, I. A.; Shevtsova, E. S.

    2016-01-01

    We discuss the possibility of finding the birthplaces of open clusters (OC) with ages of several billion years. The proposed method is based on the comparison of the results of the chemical evolution modeling of the Galactic disk with the parameters of the cluster. Five OCs older than 7 Gyr are known: NGC6791, BH176, Collinder 261, Berkeley 17, and Berkeley 39. The oxygen and iron abundances in NGC6791 and the oxygen abundance in BH176 are twice the solar level, the heavy-element abundances in other clusters are close to the corresponding solar values. According to chemical evolution models, at the time of the formation of the objects considered the regions where the oxygen and iron abundances reached the corresponding levels extended out to 5 kpc from the Galactic center.At present time theOCs considered are located several kpc from the Galactic center. Some of these clusters are located extremely high, about 1 kpc above the disk midplane, i.e., they have been subject to some mechanism that has carried them into orbits uncharacteristic of this type of objects. It follows from a comparison with the results of chemical evolution that younger clusters with ages of 4-5 Gyr, e.g., NGC1193,M67, and others, may have formed in a broad range of Galactocentric distances. Their large heights above the disk midplane is sufficient to suggest that these clusters have moved away from their likely birthplaces. Clusters are carried far away from the Galactic disk until the present time: about 40 clusters with ages from 0 to 2 Gyr are observed at heights ranging from 300 to 750 pc.

  18. The First Billion Years project: the escape fraction of ionizing photons in the epoch of reionization

    NASA Astrophysics Data System (ADS)

    Paardekooper, Jan-Pieter; Khochfar, Sadegh; Dalla Vecchia, Claudio

    2015-08-01

    Protogalaxies forming in low-mass dark matter haloes are thought to provide the majority of ionizing photons needed to reionize the Universe, due to their high escape fractions of ionizing photons. We study how the escape fraction in high-redshift galaxies relates to the physical properties of the halo in which the galaxies form, by computing escape fractions in more than 75 000 haloes between redshifts 27 and 6 that were extracted from the First Billion Years project, high-resolution cosmological hydrodynamical simulations of galaxy formation. We find that the main constraint on the escape fraction is the gas column density in a radius of 10 pc around the stellar populations, causing a strong mass dependence of the escape fraction. The lower potential well in haloes with M200 ≲ 108 M⊙ results in low column densities that can be penetrated by radiation from young stars (age <5 Myr). In haloes with M200 ≳ 108 M⊙ supernova feedback is important, but only ˜30 per cent of the haloes in this mass range have an escape fraction higher than 1 per cent. We find a large range of escape fractions in haloes with similar properties, caused by different distributions of the dense gas in the halo. This makes it very hard to predict the escape fraction on the basis of halo properties and results in a highly anisotropic escape fraction. The strong mass dependence, the large spread and the large anisotropy of the escape fraction may strongly affect the topology of reionization and is something current models of cosmic reionization should strive to take into account.

  19. A sawtooth-like timeline for the first billion years of lunar bombardment

    NASA Astrophysics Data System (ADS)

    Morbidelli, A.; Marchi, S.; Bottke, W. F.; Kring, D. A.

    2012-11-01

    We revisit the early evolution of the Moon's bombardment. Our work combines modeling (based on plausible projectile sources and their dynamical decay rates) with constraints from the lunar crater record, radiometric ages of the youngest lunar basins, and the abundance of highly siderophile elements in the lunar crust and mantle. We deduce that the evolution of the impact flux did not decline exponentially over the first billion years of lunar history, but also there was no prominent and narrow impact spike ˜3.9Gy ago, unlike that typically envisioned in the lunar cataclysm scenario. Instead, we show the timeline of the lunar bombardment has a sawtooth-like profile, with an uptick in the impact flux near ˜4.1Gy ago. The impact flux at the beginning of this weaker cataclysm was 5-10 times higher than the immediately preceding period. The Nectaris basin should have been one of the first basins formed at the sawtooth. We predict the bombardment rate since ˜4.1Gy ago declined slowly and adhered relatively close to classic crater chronology models (Neukum and Ivanov, 1994). Overall we expect that the sawtooth event accounted for about one-fourth of the total bombardment suffered by the Moon since its formation. Consequently, considering that ˜12-14 basins formed during the sawtooth event, we expect that the net number of basins formed on the Moon was ˜45-50. From our expected bombardment timeline, we derived a new and improved lunar chronology suitable for use on pre-Nectarian surface units. According to this chronology, a significant portion of the oldest lunar cratered terrains has an age of 4.38-4.42 Gyr. Moreover, the largest lunar basin, South Pole Aitken, is older than 4.3 Gy, and therefore was not produced during the lunar cataclysm.

  20. Switching To Less-Expensive Blindness Drug Could Save Medicare Part B $18 Billion Over A Ten-Year Period

    PubMed Central

    Hutton, DW; Newman-Casey, PA; Tavag, M; Zacks, DN; Stein, JD

    2014-01-01

    The biologic drugs bevacizumab and ranibizumab have revolutionized treatment of diabetic macular edema and macular degeneration, leading causes of blindness. Ophthalmologic use of these drugs has increased, now accounting for roughly one-sixth of the Medicare Part B drug budget. Ranibizumab and bevacizumab have similar efficacy and potentially minor differences in adverse event rates, but at $2,023 per dose, ranibizumab costs forty times more than bevacizumab. Using modeling methods, we predict ten-year (2010–2020) population-level costs and health benefits of using bevacizumab and ranibizumab. Our results show that if all patients were treated with the less-expensive bevacizumab instead of current usage patterns, Medicare Part B, patients, and the health care system would save $18 billion, $4.6 billion, and $29 billion, respectively. Altering patterns of use with these therapies by encouraging bevacizumab use and hastening approval of biosimilar therapies would dramatically reduce spending without substantially affecting patient outcomes. PMID:24889941

  1. Evidence for Oxygenic Photosynthesis Half a Billion Years Before the Great Oxidation Event

    NASA Astrophysics Data System (ADS)

    Planavsky, Noah; Reinhard, Chris; Asael, Dan; Lyons, Tim; Hofmann, Axel; Rouxel, Olivier

    2014-05-01

    Despite detailed investigations over the past 50 years, there is still intense debate about when oxygenic photosynthesis evolved. Current estimates span over a billion years of Earth history, ranging from prior to 3.7 Ga, the age of the oldest sedimentary rocks, to 2.4-2.3 Ga, coincident with the rise of atmospheric oxygen ("The Great Oxidation Event" or GOE). As such, a new, independent perspective is needed. We will provide such a perspective herein by using molybdenum (Mo) isotopes in a novel way to track the onset of manganese(II)oxidation and thus biological oxygen production. The oxidation of Mn(II) in modern marine setting requires free dissolved oxygen. Mn is relatively unique in its environmental specificity for oxygen as an electron acceptor among the redox-sensitive transition metals, many of which, like Fe, can be oxidized under anoxic conditions either through a microbial pathway and/or with alternative oxidants such as nitrate. There are large Mo isotope fractionations associated with the sorption of Mo (as a polymolybdate complex) onto Mn-oxyhydroxides, with an approximately -2.7‰ fractionation in d98Mo associated with Mo sorption onto Mn-oxyhydroxides (e.g., birnessite, vernadite). In contrast, sorption of Mo onto the Fe-oxyhydroxide (e.g., ferrihydrite) results in a fractionation of only -1.1‰ or less. Because of this difference in Mo isotope fractionation, Mo isotope values should become lighter with increasing Mn content, if Mn oxidation occurred during deposition and is an important vector of Mo transfer to the sediment. We find a strong positive correlation between d98Mo values and Fe/Mn ratios in iron formations deposited before and after the Great Oxidation Event. Most strikingly, Mo isotope data and Fe/Mn ratios correlate over a 2.5‰ range in d98Mo values in the Mn-rich (0.1 - 6%) iron formation of the 2.95 Ga Sinqeni Formation, South Africa. The large isotopic shifts occur over a relatively thin (3 meter thick) horizon, reflecting

  2. $17 billion needed for population programme to year 2000: Dr. Nafis Sadik launches State of World Population Report.

    PubMed

    1995-01-01

    Dr. Nafis Sadik, Executive Director of the United Nations Population Fund (UNFPA), in her address on July 11 to the Foreign Press Association in London on the occasion of the release of the "1995 State of the World Population Report," stated that governments needed to invest in people, and that the estimated amount needed to reduce population numbers in developing countries was $17 billion for the year 2000. Two-thirds of the cost would be supplied by the developing countries. She said that coordinating population policies globally through such documents as the Programme of Action from the Cairo Conference would aid in slowing population growth. World population, currently 5.7 billion, is projected to reach 7.1-7.83 billion in 2015 and 7.9-11.9 billion in 2050. She also noted that certain conditions faced by women bear upon unsustainable population growth. The cycle of poverty continues in developing countries because very young mothers, who face higher risks in pregnancy and childbirth than those who delay childbearing until after the age of 20, are less likely to continue their education, more likely to have lower-paying jobs, and have a higher rate of separation and divorce. The isolation of women from widespread political participation and the marginalization of women's concerns from mainstream topics has resulted in ineffective family planning programs, including prevention of illness or impairment related to pregnancy or childbirth. Women, in most societies, cannot fully participate in economic and public life, have limited access to positions of influence and power, have narrower occupational choices and lower earnings than men, and must struggle to reconcile activities outside the home with their traditional roles. Sustainable development can only be achieved when social development expands opportunities for individuals (men and women), and their families, empowering them in the attainment of their social, economic, political, and cultural aspirations. PMID

  3. Fourteen Times the Earth

    NASA Astrophysics Data System (ADS)

    2004-08-01

    light years away. This solar-like star is located in the southern constellation Ara (the Altar) and is bright enough (5th magnitude) to be observed with the unaided eye. Mu Arae was already known to harbour a Jupiter-sized planet with a 650 days orbital period. Previous observations also hinted at the presence of another companion (a planet or a star) much further away. The new measurements obtained by the astronomers on this object, combined with data from other teams confirm this picture. But as François Bouchy, member of the team, states: "Not only did the new HARPS measurements confirm what we previously believed to know about this star but they also showed that an additional planet on short orbit was present. And this new planet appears to be the smallest yet discovered around a star other than the sun. This makes mu Arae a very exciting planetary system." "Listening" to the star ESO PR Photo 25b/04 ESO PR Photo 25b/04 Observed Velocity Variation of mu Arae [Preview - JPEG: 440 x 400 pix - 98k] [Normal - JPEG: 879 x 800 pix - 230k] ESO PR Photo 25c/04 ESO PR Photo 25c/04 Velocity Variation of mu Arae Observed by HARPS [Preview - JPEG: 460 x 400 pix - 90k] [Normal - JPEG: 919 x 800 pix - 215k] Captions: ESO PR Photo 25b/04 shows the measurements of the radial velocity of the star mu Arae obtained by HARPS on the ESO 3.6m telescope at La Silla (green triangles), CORALIE on the Swiss Leonhard Euler 1.2m telescope also on La Silla (red dots) and UCLES on the Anglo-Australian Telescope (blue circles). The solid line shows the best fit to the measurements, assuming the existence of two planets and an additional long-period companion. The fact that the line happens to have a given width is related to the existence of the newly found short period planet. The data shown span the interval from July 1998 to August 2004. ESO PR Photo 25c/04 illustrates the high-quality radial velocity measurements obtained with HARPS. Here also, the solid line shows the best fit to the

  4. Fourteen Times the Earth

    NASA Astrophysics Data System (ADS)

    2004-08-01

    light years away. This solar-like star is located in the sout

  5. A spin-down clock for cool stars from observations of a 2.5-billion-year-old cluster.

    PubMed

    Meibom, Søren; Barnes, Sydney A; Platais, Imants; Gilliland, Ronald L; Latham, David W; Mathieu, Robert D

    2015-01-29

    The ages of the most common stars--low-mass (cool) stars like the Sun, and smaller--are difficult to derive because traditional dating methods use stellar properties that either change little as the stars age or are hard to measure. The rotation rates of all cool stars decrease substantially with time as the stars steadily lose their angular momenta. If properly calibrated, rotation therefore can act as a reliable determinant of their ages based on the method of gyrochronology. To calibrate gyrochronology, the relationship between rotation period and age must be determined for cool stars of different masses, which is best accomplished with rotation period measurements for stars in clusters with well-known ages. Hitherto, such measurements have been possible only in clusters with ages of less than about one billion years, and gyrochronology ages for older stars have been inferred from model predictions. Here we report rotation period measurements for 30 cool stars in the 2.5-billion-year-old cluster NGC 6819. The periods reveal a well-defined relationship between rotation period and stellar mass at the cluster age, suggesting that ages with a precision of order 10 per cent can be derived for large numbers of cool Galactic field stars. PMID:25539085

  6. A spin-down clock for cool stars from observations of a 2.5-billion-year-old cluster

    NASA Astrophysics Data System (ADS)

    Meibom, Søren; Barnes, Sydney A.; Platais, Imants; Gilliland, Ronald L.; Latham, David W.; Mathieu, Robert D.

    2015-01-01

    The ages of the most common stars--low-mass (cool) stars like the Sun, and smaller--are difficult to derive because traditional dating methods use stellar properties that either change little as the stars age or are hard to measure. The rotation rates of all cool stars decrease substantially with time as the stars steadily lose their angular momenta. If properly calibrated, rotation therefore can act as a reliable determinant of their ages based on the method of gyrochronology. To calibrate gyrochronology, the relationship between rotation period and age must be determined for cool stars of different masses, which is best accomplished with rotation period measurements for stars in clusters with well-known ages. Hitherto, such measurements have been possible only in clusters with ages of less than about one billion years, and gyrochronology ages for older stars have been inferred from model predictions. Here we report rotation period measurements for 30 cool stars in the 2.5-billion-year-old cluster NGC 6819. The periods reveal a well-defined relationship between rotation period and stellar mass at the cluster age, suggesting that ages with a precision of order 10 per cent can be derived for large numbers of cool Galactic field stars.

  7. An age difference of two billion years between a metal-rich and a metal-poor globular cluster.

    PubMed

    Hansen, B M S; Kalirai, J S; Anderson, J; Dotter, A; Richer, H B; Rich, R M; Shara, M M; Fahlman, G G; Hurley, J R; King, I R; Reitzel, D; Stetson, P B

    2013-08-01

    Globular clusters trace the formation history of the spheroidal components of our Galaxy and other galaxies, which represent the bulk of star formation over the history of the Universe. The clusters exhibit a range of metallicities (abundances of elements heavier than helium), with metal-poor clusters dominating the stellar halo of the Galaxy, and higher-metallicity clusters found within the inner Galaxy, associated with the stellar bulge, or the thick disk. Age differences between these clusters can indicate the sequence in which the components of the Galaxy formed, and in particular which clusters were formed outside the Galaxy and were later engulfed along with their original host galaxies, and which were formed within it. Here we report an absolute age of 9.9 ± 0.7 billion years (at 95 per cent confidence) for the metal-rich globular cluster 47 Tucanae, determined by modelling the properties of the cluster's white-dwarf cooling sequence. This is about two billion years younger than has been inferred for the metal-poor cluster NGC 6397 from the same models, and provides quantitative evidence that metal-rich clusters like 47 Tucanae formed later than metal-poor halo clusters like NGC 6397. PMID:23903747

  8. Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels

    NASA Astrophysics Data System (ADS)

    Som, Sanjoy M.; Buick, Roger; Hagadorn, James W.; Blake, Tim S.; Perreault, John M.; Harnmeijer, Jelte P.; Catling, David C.

    2016-06-01

    How the Earth stayed warm several billion years ago when the Sun was considerably fainter is the long-standing problem of the `faint young Sun paradox'. Because of negligible O2 and only moderate CO2 levels in the Archaean atmosphere, methane has been invoked as an auxiliary greenhouse gas. Alternatively, pressure broadening in a thicker atmosphere with a N2 partial pressure around 1.6-2.4 bar could have enhanced the greenhouse effect. But fossilized raindrop imprints indicate that air pressure 2.7 billion years ago (Gyr) was below twice modern levels and probably below 1.1 bar, precluding such pressure enhancement. This result is supported by nitrogen and argon isotope studies of fluid inclusions in 3.0-3.5 Gyr rocks. Here, we calculate absolute Archaean barometric pressure using the size distribution of gas bubbles in basaltic lava flows that solidified at sea level ~2.7 Gyr in the Pilbara Craton, Australia. Our data indicate a surprisingly low surface atmospheric pressure of Patm = 0.23 +/- 0.23 (2σ) bar, and combined with previous studies suggests ~0.5 bar as an upper limit to late Archaean Patm. The result implies that the thin atmosphere was rich in auxiliary greenhouse gases and that Patm fluctuated over geologic time to a previously unrecognized extent.

  9. Tracing the effects of an enormous meteorite impact 3 billion years ago

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-07-01

    The most well-known and popularized meteorite impact occurred 65 million years ago and left behind the Chicxulub crater, a feature more than 110 miles in diameter. Dust kicked up by the impact, which lingered in the atmosphere for years, may have helped kill all the nonavian dinosaurs along with three quarters of the world's plant and animal species.

  10. A Record Year at the Federal Trough: Colleges Feast on $1.67-Billion in Earmarks.

    ERIC Educational Resources Information Center

    Brainard, Jeffrey; Southwick, Ron

    2001-01-01

    Discusses how for fiscal year 2001, Congress earmarked more money for federal projects for specific colleges than ever before. It provided a 60 percent increase over the previous year, although such earmarks have drawn criticism as wasteful and harmful to merit-based competition for funds. Includes a list of top recipients of "pork." (EV)

  11. The Archean Dongwanzi ophiolite complex, North China craton: 2.505-billion-year-old oceanic crust and mantle.

    PubMed

    Kusky, T M; Li, J H; Tucker, R D

    2001-05-11

    We report a thick, laterally extensive 2505 +/- 2.2-million-year-old (uranium-lead ratio in zircon) Archean ophiolite complex in the North China craton. Basal harzburgite tectonite is overlain by cumulate ultramafic rocks, a mafic-ultramafic transition zone of interlayered gabbro and ultramafic cumulates, compositionally layered olivine-gabbro and pyroxenite, and isotropic gabbro. A sheeted dike complex is rooted in the gabbro and overlain by a mixed dike-pillow lava section, chert, and banded iron formation. The documentation of a complete Archean ophiolite implies that mechanisms of oceanic crustal accretion similar to those of today were in operation by 2.5 billion years ago at divergent plate margins and that the temperature of the early mantle was not extremely elevated, as compared to the present-day temperature. Plate tectonic processes similar to those of the present must also have emplaced the ophiolite in a convergent margin setting. PMID:11349144

  12. States' Tax Funds for Colleges Top $28-Billion, Up 16 Pct. in 2 Years.

    ERIC Educational Resources Information Center

    Evangelauf, Jean

    1984-01-01

    The results of an annual national survey of state appropriations for higher education are analyzed and discussed and it is suggested that the 16 percent increase in a two-year period may mark the beginning of a recovery for tax support of higher education. (MSE)

  13. Plate tectonics 2.5 billion years ago - Evidence at Kolar, south India

    NASA Technical Reports Server (NTRS)

    Krogstad, E. J.; Hanson, G. N.; Balakrishnan, S.; Rajamani, V.; Mukhopadhyay, D. K.

    1989-01-01

    The Archean Kolar Schist Belt, south India, is a suture zone where two gneiss terranes and at least two amphibolite terranes with distinct histories were accreted. Amphibolites from the eastern and western sides of the schist belt have distinct incompatible element and isotopic characteristics suggesting that their volcanic protoliths were derived from different mantle sources. The amphibolite and gneiss terranes were juxtaposed by horizontal compression and shearing between 2530 and 2420 million years ago (Ma) along a zone marked by the Kolar Schist Belt. This history of accretion of discrete crustal terranes resembles those of Phanerozoic convergent margins and thus suggests that plate tectonics operated on earth by 2500 Ma.

  14. 1.8 Billion Years of Detrital Zircon Recycling Calibrates a Refractory Part of Earth's Sedimentary Cycle.

    PubMed

    Hadlari, Thomas; Swindles, Graeme T; Galloway, Jennifer M; Bell, Kimberley M; Sulphur, Kyle C; Heaman, Larry M; Beranek, Luke P; Fallas, Karen M

    2015-01-01

    Detrital zircon studies are providing new insights on the evolution of sedimentary basins but the role of sedimentary recycling remains largely undefined. In a broad region of northwestern North America, this contribution traces the pathway of detrital zircon sand grains from Proterozoic sandstones through Phanerozoic strata and argues for multi-stage sedimentary recycling over more than a billion years. As a test of our hypothesis, integrated palynology and detrital zircon provenance provides clear evidence for erosion of Carboniferous strata in the northern Cordillera as a sediment source for Upper Cretaceous strata. Our results help to calibrate Earth's sedimentary cycle by showing that recycling dominates sedimentary provenance for the refractory mineral zircon. PMID:26658165

  15. Constraint on a varying proton-electron mass ratio 1.5 billion years after the big bang.

    PubMed

    Bagdonaite, J; Ubachs, W; Murphy, M T; Whitmore, J B

    2015-02-20

    A molecular hydrogen absorber at a lookback time of 12.4 billion years, corresponding to 10% of the age of the Universe today, is analyzed to put a constraint on a varying proton-electron mass ratio, μ. A high resolution spectrum of the J1443+2724 quasar, which was observed with the Very Large Telescope, is used to create an accurate model of 89 Lyman and Werner band transitions whose relative frequencies are sensitive to μ, yielding a limit on the relative deviation from the current laboratory value of Δμ/μ=(-9.5 ± 5.4(stat)± 5.3(syst))×10(-6). PMID:25763949

  16. 1.8 Billion Years of Detrital Zircon Recycling Calibrates a Refractory Part of Earth’s Sedimentary Cycle

    PubMed Central

    Hadlari, Thomas; Swindles, Graeme T.; Galloway, Jennifer M.; Bell, Kimberley M.; Sulphur, Kyle C.; Heaman, Larry M.; Beranek, Luke P.; Fallas, Karen M.

    2015-01-01

    Detrital zircon studies are providing new insights on the evolution of sedimentary basins but the role of sedimentary recycling remains largely undefined. In a broad region of northwestern North America, this contribution traces the pathway of detrital zircon sand grains from Proterozoic sandstones through Phanerozoic strata and argues for multi-stage sedimentary recycling over more than a billion years. As a test of our hypothesis, integrated palynology and detrital zircon provenance provides clear evidence for erosion of Carboniferous strata in the northern Cordillera as a sediment source for Upper Cretaceous strata. Our results help to calibrate Earth's sedimentary cycle by showing that recycling dominates sedimentary provenance for the refractory mineral zircon. PMID:26658165

  17. Taking out one billion tones of carbon: the magic of China's 11thFive-Year Plan

    SciTech Connect

    Lin, Jiang; Zhou, Nan; Levine, Mark D.; Fridley, David

    2007-05-01

    China's 11th Five-Year Plan (FYP) sets an ambitious targetfor energy-efficiency improvement: energy intensity of the country sgross domestic product (GDP) should be reduced by 20 percent from 2005 to2010 (NDRC, 2006). This is the first time that a quantitative and bindingtarget has been set for energy efficiency, and signals a major shift inChina's strategic thinking about its long-term economic and energydevelopment. The 20 percent energy intensity target also translates intoan annual reduction of over one billion tons of CO2 by 2010, making theChinese effort one of most significant carbon mitigation effort in theworld today. While it is still too early to tell whether China willachieve this target, this paper attempts to understand the trend inenergy intensity in China and to explore a variety of options towardmeeting the 20 percent target using a detailed endues energymodel.

  18. Taking out 1 billion tons of CO2: The magic of China's 11th Five-Year Plan?

    SciTech Connect

    Zhou, Nan; Lin, Jiang; Zhou, Nan; Levine, Mark; Fridley, David

    2007-07-01

    China's 11th Five-Year Plan (FYP) sets an ambitious target for energy-efficiency improvement: energy intensity of the country's gross domestic product (GDP) should be reduced by 20% from 2005 to 2010 (NDRC, 2006). This is the first time that a quantitative and binding target has been set for energy efficiency, and signals a major shift in China's strategic thinking about its long-term economic and energy development. The 20% energy intensity target also translates into an annual reduction of over 1.5 billion tons of CO2 by 2010, making the Chinese effort one of most significant carbon mitigation effort in the world today. While it is still too early to tell whether China will achieve this target, this paper attempts to understand the trend in energy intensity in China and to explore a variety of options toward meeting the 20% target using a detailed end-use energy model.

  19. Hematite formation by oxygenated groundwater more than 2.76 billion years ago

    NASA Astrophysics Data System (ADS)

    Kato, Yasuhiro; Suzuki, Katsuhiko; Nakamura, Kentaro; Hickman, Arthur H.; Nedachi, Munetomo; Kusakabe, Minoru; Bevacqua, David C.; Ohmoto, Hiroshi

    2009-02-01

    Geoscientific drilling in the Marble Bar area of the Pilbara Craton, Western Australia, resulted in the discovery of locally abundant hematite in Archean basalts ~ 200 m below the present land surface. The hematized basalts occurring along a bedding-parallel shear zone are cross-cut by pyrite veinlets (< 3 mm in width) and contain euhedral pyrite grains (10-500 µm in diameter) with sharp crystal edges, indicating that the hematite formed before the pyrite. We have dated the pyrite in the veinlets at 2.763 ± 0.016 Ga using the Re-Os method. Therefore, the hematite formed prior to 2.763 Ga. The basalts containing the hematite belong to the Apex Basalt of the Warrawoona Group, and were erupted onto the Archean seafloor at 3.46 Ga. Due to 2.9 Ga orogenic deformation and subsequent deep erosion, the Apex Basalt was exposed at the surface of a continental landmass prior to 2.77 Ga. Sometime in the period between ~ 2.9 Ga and 2.77 Ga, the basalt section we describe was less than 200 m below the Late Archean land surface, and within range of groundwater percolation through the shear zone in the basalts. Geological, mineralogical and geochemical lines of evidence strongly suggest that the infiltration of O 2-rich groundwater through the bedding-parallel shear in the basalts formed hematite prior to 2.76 Ga, and hence oxygenated surface environments, at least localized and/or short-lived, emerged more than 300 million years before the widely accepted Great Oxidation Event during 2.45 and 2.32 Ga.

  20. 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

  1. 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

  2. Decimetre-scale multicellular eukaryotes from the 1.56-billion-year-old Gaoyuzhuang Formation in North China.

    PubMed

    Zhu, Shixing; Zhu, Maoyan; Knoll, Andrew H; Yin, Zongjun; Zhao, Fangchen; Sun, Shufen; Qu, Yuangao; Shi, Min; Liu, Huan

    2016-01-01

    Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635-541 million years (Myr)), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1,560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossils have statistically regular linear to lanceolate shapes up to 30 cm long and nearly 8 cm wide, suggesting that the Gaoyuzhuang fossils record benthic multicellular eukaryotes of unprecedentedly large size. Syngenetic fragments showing closely packed ∼10 μm cells arranged in a thick sheet further reinforce the interpretation. Comparisons with living thalloid organisms suggest that these organisms were photosynthetic, although their phylogenetic placement within the Eukarya remains uncertain. The new fossils provide the strongest evidence yet that multicellular eukaryotes with decimetric dimensions and a regular developmental program populated the marine biosphere at least a billion years before the Cambrian Explosion. PMID:27186667

  3. The controversial “Cambrian” fossils of the Vindhyan are real but more than a billion years older

    PubMed Central

    Bengtson, Stefan; Belivanova, Veneta; Rasmussen, Birger; Whitehouse, Martin

    2009-01-01

    The age of the Vindhyan sedimentary basin in central India is controversial, because geochronology indicating early Proterozoic ages clashes with reports of Cambrian fossils. We present here an integrated paleontologic–geochronologic investigation to resolve this conundrum. New sampling of Lower Vindhyan phosphoritic stromatolitic dolomites from the northern flank of the Vindhyans confirms the presence of fossils most closely resembling those found elsewhere in Cambrian deposits: annulated tubes, embryo-like globules with polygonal surface pattern, and filamentous and coccoidal microbial fabrics similar to Girvanella and Renalcis. None of the fossils, however, can be ascribed to uniquely Cambrian or Ediacaran taxa. Indeed, the embryo-like globules are not interpreted as fossils at all but as former gas bubbles trapped in mucus-rich cyanobacterial mats. Direct dating of the same fossiliferous phosphorite yielded a Pb–Pb isochron of 1,650 ± 89 (2σ) million years ago, confirming the Paleoproterozoic age of the fossils. New U–Pb geochronology of zircons from tuffaceous mudrocks in the Lower Vindhyan Porcellanite Formation on the southern flank of the Vindhyans give comparable ages. The Vindhyan phosphorites provide a window of 3-dimensionally preserved Paleoproterozoic fossils resembling filamentous and coccoidal cyanobacteria and filamentous eukaryotic algae, as well as problematic forms. Like Neoproterozoic phosphorites a billion years later, the Vindhyan deposits offer important new insights into the nature and diversity of life, and in particular, the early evolution of multicellular eukaryotes. PMID:19416859

  4. Decimetre-scale multicellular eukaryotes from the 1.56-billion-year-old Gaoyuzhuang Formation in North China

    PubMed Central

    Zhu, Shixing; Zhu, Maoyan; Knoll, Andrew H.; Yin, Zongjun; Zhao, Fangchen; Sun, Shufen; Qu, Yuangao; Shi, Min; Liu, Huan

    2016-01-01

    Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635–541 million years (Myr)), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1,560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossils have statistically regular linear to lanceolate shapes up to 30 cm long and nearly 8 cm wide, suggesting that the Gaoyuzhuang fossils record benthic multicellular eukaryotes of unprecedentedly large size. Syngenetic fragments showing closely packed ∼10 μm cells arranged in a thick sheet further reinforce the interpretation. Comparisons with living thalloid organisms suggest that these organisms were photosynthetic, although their phylogenetic placement within the Eukarya remains uncertain. The new fossils provide the strongest evidence yet that multicellular eukaryotes with decimetric dimensions and a regular developmental program populated the marine biosphere at least a billion years before the Cambrian Explosion. PMID:27186667

  5. A large population of galaxies 9 to 12 billion years back in the history of the Universe.

    PubMed

    Le Fèvre, O; Paltani, S; Arnouts, S; Charlot, S; Foucaud, S; Ilbert, O; McCracken, H J; Zamorani, G; Bottini, D; Garilli, B; Le Brun, V; Maccagni, D; Picat, J P; Scaramella, R; Scodeggio, M; Tresse, L; Vettolani, G; Zanichelli, A; Adami, C; Bardelli, S; Bolzonella, M; Cappi, A; Ciliegi, P; Contini, T; Franzetti, P; Gavignaud, I; Guzzo, L; Iovino, A; Marano, B; Marinoni, C; Mazure, A; Meneux, B; Merighi, R; Pellò, R; Pollo, A; Pozzetti, L; Radovich, M; Zucca, E; Arnaboldi, M; Bondi, M; Bongiorno, A; Busarello, G; Gregorini, L; Lamareille, F; Mathez, G; Mellier, Y; Merluzzi, P; Ripepi, V; Rizzo, D

    2005-09-22

    To understand the evolution of galaxies, we need to know as accurately as possible how many galaxies were present in the Universe at different epochs. Galaxies in the young Universe have hitherto mainly been identified using their expected optical colours, but this leaves open the possibility that a significant population remains undetected because their colours are the result of a complex mix of stars, gas, dust or active galactic nuclei. Here we report the results of a flux-limited I-band survey of galaxies at look-back times of 9 to 12 billion years. We find 970 galaxies with spectroscopic redshifts between 1.4 and 5. This population is 1.6 to 6.2 times larger than previous estimates, with the difference increasing towards brighter magnitudes. Strong ultraviolet continua (in the rest frame of the galaxies) indicate vigorous star formation rates of more than 10-100 solar masses per year. As a consequence, the cosmic star formation rate representing the volume-averaged production of stars is higher than previously measured at redshifts of 3 to 4. PMID:16177783

  6. A One Billion Year Martian Climate Model: The Importance of Seasonally Resolved Polar Caps and the Role of Wind

    NASA Technical Reports Server (NTRS)

    Armstrong, J. C.; Leovy, C. B.; Quinn, T. R.; Haberle, R. M.; Schaeffer, J.

    2003-01-01

    Wind deflation and deposition are powerful agents of surface change in the present Mars climate regime. Recent studies indicate that, while the distribution of regions of potential deflation (or erosion) and deposition is remarkably insensitive to changes in orbital parameters (obliquity, timing of perihelion passage, etc.), rates of aeolian surface modification may be highly sensitive to these parameters even if the atmospheric mass remains constant. But previous work suggested the atmospheric mass is likely to be sensitive to obliquity, especially if a significant mass of carbon dioxide can be stored in the regolith or deposited in the form of massive polar caps. Deflation and erosion are highly sensitive to surface pressure, so feedback between orbit variations and surface pressure can greatly enhance the sensitivity of aeolian modification rates to orbital parameters. We used statistics derived from a 1 Gyr orbital integration of the spin axis of Mars, coupled with 3D general circulation models (GCMs) at a variety of orbital conditions and pressures, to explore this feedback. We also employed a seasonally resolved 1D energy balance model to illuminate the gross characteristics of the longterm atmospheric evolution, wind erosion and deposition over one billion years. We find that seasonal polar cycles have a critical influence on the ability for the regolith to release CO2 at high obliquities, and find that the atmospheric CO2 actually decreases at high obliquities due to the cooling effect of polar deposits at latitudes where seasonal caps form. At low obliquity, the formation of massive, permanent polar caps depends critically on the values of the frost albedo, A(sub frost), and frost emissivity, E(sub frost). Using our 1D model with values of A(sub frost) = 0.67 and E(sub frost) = 0.55, matched to the NASA Ames GCM results, we find that permanent caps only form at low obliquities (< 10 degrees). Thus, contrary to expectations, the Martian atmospheric pressure

  7. Evidence from massive siderite beds for a CO2-rich atmosphere before approximately 1.8 billion years ago

    NASA Technical Reports Server (NTRS)

    Ohmoto, Hiroshi; Watanabe, Yumiko; Kumazawa, Kazumasa

    2004-01-01

    It is generally thought that, in order to compensate for lower solar flux and maintain liquid oceans on the early Earth, methane must have been an important greenhouse gas before approximately 2.2 billion years (Gyr) ago. This is based upon a simple thermodynamic calculation that relates the absence of siderite (FeCO3) in some pre-2.2-Gyr palaeosols to atmospheric CO2 concentrations that would have been too low to have provided the necessary greenhouse effect. Using multi-dimensional thermodynamic analyses and geological evidence, we show here that the absence of siderite in palaeosols does not constrain atmospheric CO2 concentrations. Siderite is absent in many palaeosols (both pre- and post-2.2-Gyr in age) because the O2 concentrations and pH conditions in well-aerated soils have favoured the formation of ferric (Fe3+)-rich minerals, such as goethite, rather than siderite. Siderite, however, has formed throughout geological history in subsurface environments, such as euxinic seas, where anaerobic organisms created H2-rich conditions. The abundance of large, massive siderite-rich beds in pre-1.8-Gyr sedimentary sequences and their carbon isotope ratios indicate that the atmospheric CO2 concentration was more than 100 times greater than today, causing the rain and ocean waters to be more acidic than today. We therefore conclude that CO2 alone (without a significant contribution from methane) could have provided the necessary greenhouse effect to maintain liquid oceans on the early Earth.

  8. Sulfur isotopes of organic matter preserved in 3.45-billion-year-old stromatolites reveal microbial metabolism.

    PubMed

    Bontognali, Tomaso R R; Sessions, Alex L; Allwood, Abigail C; Fischer, Woodward W; Grotzinger, John P; Summons, Roger E; Eiler, John M

    2012-09-18

    The 3.45-billion-year-old Strelley Pool Formation of Western Australia preserves stromatolites that are considered among the oldest evidence for life on Earth. In places of exceptional preservation, these stromatolites contain laminae rich in organic carbon, interpreted as the fossil remains of ancient microbial mats. To better understand the biogeochemistry of these rocks, we performed microscale in situ sulfur isotope measurements of the preserved organic sulfur, including both Δ(33)S and . This approach allows us to tie physiological inference from isotope ratios directly to fossil biomass, providing a means to understand sulfur metabolism that is complimentary to, and independent from, inorganic proxies (e.g., pyrite). Δ(33)S values of the kerogen reveal mass-anomalous fractionations expected of the Archean sulfur cycle, whereas values show large fractionations at very small spatial scales, including values below -15‰. We interpret these isotopic patterns as recording the process of sulfurization of organic matter by H(2)S in heterogeneous mat pore-waters influenced by respiratory S metabolism. Positive Δ(33)S anomalies suggest that disproportionation of elemental sulfur would have been a prominent microbial process in these communities. PMID:22949693

  9. Sulfur isotopes of organic matter preserved in 3.45-billion-year-old stromatolites reveal microbial metabolism

    PubMed Central

    Bontognali, Tomaso R. R.; Sessions, Alex L.; Allwood, Abigail C.; Fischer, Woodward W.; Grotzinger, John P.; Summons, Roger E.; Eiler, John M.

    2012-01-01

    The 3.45-billion-year-old Strelley Pool Formation of Western Australia preserves stromatolites that are considered among the oldest evidence for life on Earth. In places of exceptional preservation, these stromatolites contain laminae rich in organic carbon, interpreted as the fossil remains of ancient microbial mats. To better understand the biogeochemistry of these rocks, we performed microscale in situ sulfur isotope measurements of the preserved organic sulfur, including both Δ33S and . This approach allows us to tie physiological inference from isotope ratios directly to fossil biomass, providing a means to understand sulfur metabolism that is complimentary to, and independent from, inorganic proxies (e.g., pyrite). Δ33S values of the kerogen reveal mass-anomalous fractionations expected of the Archean sulfur cycle, whereas values show large fractionations at very small spatial scales, including values below -15‰. We interpret these isotopic patterns as recording the process of sulfurization of organic matter by H2S in heterogeneous mat pore-waters influenced by respiratory S metabolism. Positive Δ33S anomalies suggest that disproportionation of elemental sulfur would have been a prominent microbial process in these communities. PMID:22949693

  10. Mobile hydrocarbon microspheres from >2-billion-year-old carbon-bearing seams in the South African deep subsurface.

    PubMed

    Wanger, G; Moser, D; Hay, M; Myneni, S; Onstott, T C; Southam, G

    2012-11-01

    By ~2.9 Ga, the time of the deposition of the Witwatersrand Supergroup, life is believed to have been well established on Earth. Carbon remnants of the microbial biosphere from this time period are evident in sediments from around the world. In the Witwatersrand Supergroup, the carbonaceous material is often concentrated in seams, closely associated with the gold deposits and may have been a mobile phase 2 billion years ago. Whereas today the carbon in the Witwatersrand Supergroup is presumed to be immobile, hollow hydrocarbon spheres ranging in size from <1 μm to >50 μm were discovered emanating from a borehole drilled through the carbon-bearing seams suggesting that a portion of the carbon may still be mobile in the deep subsurface. ToF-SIMS and STXM analyses revealed that these spheres contain a suite of alkane, alkenes, and aromatic compounds consistent with the described organic-rich carbon seams within the Witwatersrand Supergroup's auriferous reef horizons. Analysis by electron microscopy and ToF-SIMS, however, revealed that these spheres, although most likely composed of biogenic carbon and resembling biological organisms, do not retain any true structural, that is, fossil, information and were formed by an abiogenic process. PMID:22901282

  11. The thesis of stages fourteen years later

    NASA Astrophysics Data System (ADS)

    Beeby, C. E.

    1980-12-01

    The author indicates the changes and additions he would make to his book ` The Quality of Education in Developing Countries' (1966) if he were re-writing it in 1980. He would make clearer that his primary interest is in a continuum of change, the process of growth of a school system, and that the `stages' are only a convenient non-mathematical artifact to make the thesis more useful to administrators and planners. In the light of more recent developments and experiences, he now gives new stress to the pluralism of objectives at the stage of Meaning, and discusses the political, social, cultural and financial reasons why a country may choose not to take the difficult step from stage III to stage IV. Recent forms of alternative education, particularly those embodying plans for lifelong education, offer some hope of bypassing his thesis of stages. More consideration is given to constraints other than that of teacher qualification, though the difficulty of changing the skills, habits, attitudes and purposes in the teaching profession remain the chief obstacle to qualitative growth. Particular attention is paid to `crash' programmes where processes that are, by their very nature, successive are compressed into simultaneous or almost simultaneous ones. Some implications of the thesis of stages for teacher training are briefly dealt with. Regarding the application of the thesis to secondary education, he maintains that a better model of growth would be one based on the capacity of secondary education to respond to the changing economic and social demands of the community. Finally, he suggests three methods of testing his hypotheses and pleads that more consideration be given to building up a body of educational, theory based on the experience of developing countries over the past three decades.

  12. Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints.

    PubMed

    Som, Sanjoy M; Catling, David C; Harnmeijer, Jelte P; Polivka, Peter M; Buick, Roger

    2012-04-19

    According to the 'Faint Young Sun' paradox, during the late Archaean eon a Sun approximately 20% dimmer warmed the early Earth such that it had liquid water and a clement climate. Explanations for this phenomenon have invoked a denser atmosphere that provided warmth by nitrogen pressure broadening or enhanced greenhouse gas concentrations. Such solutions are allowed by geochemical studies and numerical investigations that place approximate concentration limits on Archaean atmospheric gases, including methane, carbon dioxide and oxygen. But no field data constraining ground-level air density and barometric pressure have been reported, leaving the plausibility of these various hypotheses in doubt. Here we show that raindrop imprints in tuffs of the Ventersdorp Supergroup, South Africa, constrain surface air density 2.7 billion years ago to less than twice modern levels. We interpret the raindrop fossils using experiments in which water droplets of known size fall at terminal velocity into fresh and weathered volcanic ash, thus defining a relationship between imprint size and raindrop impact momentum. Fragmentation following raindrop flattening limits raindrop size to a maximum value independent of air density, whereas raindrop terminal velocity varies as the inverse of the square root of air density. If the Archaean raindrops reached the modern maximum measured size, air density must have been less than 2.3 kg m(-3), compared to today's 1.2 kg m(-3), but because such drops rarely occur, air density was more probably below 1.3 kg m(-3). The upper estimate for air density renders the pressure broadening explanation possible, but it is improbable under the likely lower estimates. Our results also disallow the extreme CO(2) levels required for hot Archaean climates. PMID:22456703

  13. Legius syndrome in fourteen families.

    PubMed

    Denayer, Ellen; Chmara, Magdalena; Brems, Hilde; Kievit, Anneke Maat; van Bever, Yolande; Van den Ouweland, Ans M W; Van Minkelen, Rick; de Goede-Bolder, Arja; Oostenbrink, Rianne; Lakeman, Phillis; Beert, Eline; Ishizaki, Takuma; Mori, Tomoaki; Keymolen, Kathelijn; Van den Ende, Jenneke; Mangold, Elisabeth; Peltonen, Sirkku; Brice, Glen; Rankin, Julia; Van Spaendonck-Zwarts, Karin Y; Yoshimura, Akihiko; Legius, Eric

    2011-01-01

    Legius syndrome presents as an autosomal dominant condition characterized by café-au-lait macules with or without freckling and sometimes a Noonan-like appearance and/or learning difficulties. It is caused by germline loss-of-function SPRED1 mutations and is a member of the RAS-MAPK pathway syndromes. Most mutations result in a truncated protein and only a few inactivating missense mutations have been reported. Since only a limited number of patients has been reported up until now, the full clinical and mutational spectrum is still unknown. We report mutation data and clinical details in fourteen new families with Legius syndrome. Six novel germline mutations are described. The Trp31Cys mutation is a new pathogenic SPRED1 missense mutation. Clinical details in the 14 families confirmed the absence of neurofibromas, and Lisch nodules, and the absence of a high prevalence of central nervous system tumors. We report white matter T2 hyperintensities on brain MRI scans in 2 patients and a potential association between postaxial polydactyly and Legius syndrome. PMID:21089071

  14. Legius Syndrome in Fourteen Families

    PubMed Central

    Denayer, Ellen; Chmara, Magdalena; Brems, Hilde; Kievit, Anneke Maat; van Bever, Yolande; Van den Ouweland, Ans MW; Van Minkelen, Rick; de Goede-Bolder, Arja; Oostenbrink, Rianne; Lakeman, Phillis; Beert, Eline; Ishizaki, Takuma; Mori, Tomoaki; Keymolen, Kathelijn; Van den Ende, Jenneke; Mangold, Elisabeth; Peltonen, Sirkku; Brice, Glen; Rankin, Julia; Van Spaendonck-Zwarts, Karin Y; Yoshimura, Akihiko; Legius, Eric

    2011-01-01

    Legius syndrome presents as an autosomal dominant condition characterized by café-au-lait macules with or without freckling and sometimes a Noonan-like appearance and/or learning difficulties. It is caused by germline loss-of-function SPRED1 mutations and is a member of the RAS-MAPK pathway syndromes. Most mutations result in a truncated protein and only a few inactivating missense mutations have been reported. Since only a limited number of patients has been reported up until now, the full clinical and mutational spectrum is still unknown. We report mutation data and clinical details in fourteen new families with Legius syndrome. Six novel germline mutations are described. The Trp31Cys mutation is a new pathogenic SPRED1 missense mutation. Clinical details in the 14 families confirmed the absence of neurofibromas, and Lisch nodules, and the absence of a high prevalence of central nervous system tumors. We report white matter T2 hyperintensities on brain MRI scans in 2 patients and a potential association between postaxial polydactyly and Legius syndrome. © 2010 Wiley-Liss, Inc. PMID:21089071

  15. Deposition of 1.88-billion-year-old iron formations as a consequence of rapid crustal growth.

    PubMed

    Rasmussen, Birger; Fletcher, Ian R; Bekker, Andrey; Muhling, Janet R; Gregory, Courtney J; Thorne, Alan M

    2012-04-26

    Iron formations are chemical sedimentary rocks comprising layers of iron-rich and silica-rich minerals whose deposition requires anoxic and iron-rich (ferruginous) sea water. Their demise after the rise in atmospheric oxygen by 2.32 billion years (Gyr) ago has been attributed to the removal of dissolved iron through progressive oxidation or sulphidation of the deep ocean. Therefore, a sudden return of voluminous iron formations nearly 500 million years later poses an apparent conundrum. Most late Palaeoproterozoic iron formations are about 1.88 Gyr old and occur in the Superior region of North America. Major iron formations are also preserved in Australia, but these were apparently deposited after the transition to a sulphidic ocean at 1.84 Gyr ago that should have terminated iron formation deposition, implying that they reflect local marine conditions. Here we date zircons in tuff layers to show that iron formations in the Frere Formation of Western Australia are about 1.88 Gyr old, indicating that the deposition of iron formations from two disparate cratons was coeval and probably reflects global ocean chemistry. The sudden reappearance of major iron formations at 1.88 Gyr ago--contemporaneous with peaks in global mafic-ultramafic magmatism, juvenile continental and oceanic crust formation, mantle depletion and volcanogenic massive sulphide formation--suggests deposition of iron formations as a consequence of major mantle activity and rapid crustal growth. Our findings support the idea that enhanced submarine volcanism and hydrothermal activity linked to a peak in mantle melting released large volumes of ferrous iron and other reductants that overwhelmed the sulphate and oxygen reservoirs of the ocean, decoupling atmospheric and seawater redox states, and causing the return of widespread ferruginous conditions. Iron formations formed on clastic-starved coastal shelves where dissolved iron upwelled and mixed with oxygenated surface water. The

  16. Dipolar geomagnetic field and low orbital obliquity during the last two billion years: Evidence from paleomagnetism of evaporite basins

    NASA Astrophysics Data System (ADS)

    Evans, D. A.

    2006-05-01

    Paleomagnetism of climatically sensitive sedimentary rock types, such as glacial deposits and evaporites, can test the uniformitarianism of ancient geomagnetic fields and paleoclimatic zones. Precambrian glacial deposits laid down in near-equatorial paleomagnetic latitudes indicate a paleoclimatic paradox that can be explained either by Snowball Earth episodes, or high orbital obliquity, or dramatically non-uniformitarian geomagnetic fields. Here I present the first global paleomagnetic compilation of the Earth's entire basin-scale evaporite record. Evaporation exceeds precipitation in today's subtropical desert belts, generally within a zone of 15-35° from the equator. Assuming a geocentric axial dipole (GAD) magnetic field for Cenozoic- Mesozoic time, evaporite basins of the past 250 Myr have a volume-weighted mean paleolatitude of 23±4°, also squarely within the subtropics. Carboniferous-Permian evaporites have an indistinguishable weighted-mean paleolatitude of 22±4°, which does not change significantly when recently hypothesized octupolar field components are included in the calculations. Early Paleozoic (including late Ediacaran) evaporites are lower-latitude (weighted mean 10±5°), but detailed analyses of individual examples show this cannot be attributed solely to nondipolar field components or sedimentary inclination biases; the cause may be due to particular paleogeographic effects on regional tropical climates, or incomplete sampling by the paleomagnetic data. Proterozoic (pre-Ediacaran) evaporite basins have a volume- weighted mean inclination of 33±4°, which would correspond to a mean paleolatitude of 18±3° for a pure GAD field. This latter mean is indistinguishable, within error, from the Cenozoic-Mesozoic mean and demonstrates the success of the GAD model as a first-order description of the geomagnetic field for the last two billion years. Also, general circulation climate models of a high-obliquity Earth predict either no strong zonal

  17. The Kepler Cluster Study: rotation period measurements for cool stars in the 2.5 billion year open cluster NGC 6819

    NASA Astrophysics Data System (ADS)

    Meibom, Soren; Barnes, Sydney A.; Platais, Imants; Gilliland, Ronald L.; Latham, David W.; Mathieu, Robert D.; Kepler Science Team, Kepler Science Operations Center

    2015-01-01

    The Kepler Cluster Study (KeCS) is a program to measure stellar rotation periods and search for planets around members of open star clusters within the field of view of NASA's Kepler mission. We present here the latest results from KeCS - measurements of stellar rotation periods in the 2.5 billion year open cluster NGC 6819 - and discuss their implications for a technique (gyrochronology) to determine stellar ages from stellar rotation.

  18. Exceptional preservation of aragonite in a circa 3.3 billion year old microbial mat from the Barberton greenstone belt, South Africa

    NASA Astrophysics Data System (ADS)

    Westall, Frances; Cavalazzi, Barbara; Lemelle, Laurence; Marrochhi, Yves; Rouzaud, Jean-Noel; Simionovici, Alexandre; Andreazza, Caroline; Foucher, Frédéric; Thiel, Volker; Hofmann, Axel

    2010-05-01

    Exceptional preservation of aragonite in a circa 3.3 billion year old microbial mat from the Barberton greenstone belt, South Africa Frances Westall, Barbara Cavalazzi, Laurence Lemelle, Yves Marrocchi, Jean-Noël Rouzaud, Alexandre Simionovici, Murielle Salomé, Smail Mostefaoui, Caroline Andreazza, Frédéric Foucher, Jan Toporski, Andrea Jauss, Volker Thiel, Axel Hofmann, Anders Meibom, François Robert Aragonite occurs as a biologically-formed mineral precipitate within modern calcifying microbial mats. It is, however, rarely preserved in the geological record because, as one of the least stable polymorphs of calcium carbonate, it readily converts to calcite in present environmental conditions at the Earth's surface. In an in situ investigation at the micro- to nanometer-scale, we show that 5-10 nm sized nanocrystals of aragonite are preserved within the organic framework of a partially calcified microbial mat from the ~ 3.3 billion year-old Josefsdal Chert in the Barberton greenstone belt, South Africa. Transformation of the aragonite to calcite was blocked by a combination of chemical inhibitors within the crystal lattice, organic molecules coating the nanocrystals and, in particular, to the precocious permeation of the mat by hydrothermal silica. Apart from its exceptional preservation for 3.3 billion years, the identification of aragonite in the Josefsdal microbial mat is the earliest evidence for in situ calcification of a microbial mat. Furthermore, the indications of associated sulphur-reducing bacteria (SRB) activity with calcification strongly support a photosynthetic origin for the mat. This is the most direct evidence for photosynthesis in early Archaean rocks.

  19. Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia

    PubMed Central

    Christian, Daniel; Wacey, David; Hazen, Robert M.

    2013-01-01

    Abstract Microbially induced sedimentary structures (MISS) result from the response of microbial mats to physical sediment dynamics. MISS are cosmopolitan and found in many modern environments, including shelves, tidal flats, lagoons, riverine shores, lakes, interdune areas, and sabkhas. The structures record highly diverse communities of microbial mats and have been reported from numerous intervals in the geological record up to 3.2 billion years (Ga) old. This contribution describes a suite of MISS from some of the oldest well-preserved sedimentary rocks in the geological record, the early Archean (ca. 3.48 Ga) Dresser Formation, Western Australia. Outcrop mapping at the meter to millimeter scale defined five sub-environments characteristic of an ancient coastal sabkha. These sub-environments contain associations of distinct macroscopic and microscopic MISS. Macroscopic MISS include polygonal oscillation cracks and gas domes, erosional remnants and pockets, and mat chips. Microscopic MISS comprise tufts, sinoidal structures, and laminae fabrics; the microscopic laminae are composed of primary carbonaceous matter, pyrite, and hematite, plus trapped and bound grains. Identical suites of MISS occur in equivalent environmental settings through the entire subsequent history of Earth including the present time. This work extends the geological record of MISS by almost 300 million years. Complex mat-forming microbial communities likely existed almost 3.5 billion years ago. Key Words: Archean—Biofilms—Microbial mats—Early Earth—Evolution. Astrobiology 13, 1103–1124. PMID:24205812

  20. Microbially induced sedimentary structures recording an ancient ecosystem in the ca. 3.48 billion-year-old Dresser Formation, Pilbara, Western Australia.

    PubMed

    Noffke, Nora; Christian, Daniel; Wacey, David; Hazen, Robert M

    2013-12-01

    Microbially induced sedimentary structures (MISS) result from the response of microbial mats to physical sediment dynamics. MISS are cosmopolitan and found in many modern environments, including shelves, tidal flats, lagoons, riverine shores, lakes, interdune areas, and sabkhas. The structures record highly diverse communities of microbial mats and have been reported from numerous intervals in the geological record up to 3.2 billion years (Ga) old. This contribution describes a suite of MISS from some of the oldest well-preserved sedimentary rocks in the geological record, the early Archean (ca. 3.48 Ga) Dresser Formation, Western Australia. Outcrop mapping at the meter to millimeter scale defined five sub-environments characteristic of an ancient coastal sabkha. These sub-environments contain associations of distinct macroscopic and microscopic MISS. Macroscopic MISS include polygonal oscillation cracks and gas domes, erosional remnants and pockets, and mat chips. Microscopic MISS comprise tufts, sinoidal structures, and laminae fabrics; the microscopic laminae are composed of primary carbonaceous matter, pyrite, and hematite, plus trapped and bound grains. Identical suites of MISS occur in equivalent environmental settings through the entire subsequent history of Earth including the present time. This work extends the geological record of MISS by almost 300 million years. Complex mat-forming microbial communities likely existed almost 3.5 billion years ago. PMID:24205812

  1. Recrystallized Granite Surface Fissures Of Wasatch Range, Produced Not Later Than 1/4 Billion Years Ago.

    NASA Astrophysics Data System (ADS)

    McDonald, K. L.

    2002-04-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, i.e., Mount T-W-M^1,6,7 Bonanza Pk.-Midway,^2 Little Cottonwood and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atm. interface, estab. that they resulted from high thermal gradients and not passages of earthquake waves.^4 Magma chambers formed, solidified during Permo-Carboniferous Ice Age (roughly 1/3...1/4 billion yr ago), a time interval preceding extrusion of Rocky Mts., 10^8 yr ago, and while fluid, some belched lava flows^5 extending over its reservoir walls to run hundreds of m. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock^7 to reach Earth's surface, so that a pluton containing large amounts of dross (Fe-ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure^3. Recryst. fissures, reaching depths of perhaps 100 m, had initial fractures near time of solidification of top portion of magma chamber, while still hot (<= 1600^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, rain water, stream flow over granite surface, partial coverage by ocean, etc., during P-C ice age - when region of Wasatch Range existed at sea level, S. L. Valley being covered entirely by ocean water and region east of Wasatch Boul. rising gently above Pac. Ocean to elev. of possibly 500-1000 ft, say, at a distance of 10-15 mi to e, as implied by Chinese wall of limestone on Grandeur Pk, another in Neff's Canyon running e from n ridge of her 9200 ft saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w, in S.L. Valley. This existed prior to regional uplift (of similar topog.) of over 4000 ft. Details of how earthquake waves form an epicenter from which propagate 2 stress fields in diam. opp. directions to open up, by a few m, surface granite to form a

  2. Recrystallized Granite Surface Fissures of Wasatch Range Produced Not Later Than 1/4Billion Years Ago

    NASA Astrophysics Data System (ADS)

    McDonald, Keith

    2000-11-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, i.e., Mount T-W-M, (K.L. McDonald, Bul. A.P.S., 32 (4), 1124),(37 (5), 1256-7),(38 (1), 740) Bonanza Pk.-Midway,(35 (9), 2132) Little Cottonwood and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atm. interface, estab that they resulted from high thermal gradients and not passages of earthquake waves.(33 (9), 1982-2) Magma chambers formed, solidified during Permo- Carboniferous Ice Age (roughly 1/3...1/4 billion yr ago), a time interval preceding extrusion, pf Rocky Mts., 10^8 yr ago, and while fluid, some belched lava flows(36 (9), 2466) extending over its reservoir walls to run hundreds of m. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock(38 (1), 740) to reach Earth's surface, so that a pluton containing large amounts of dross (Fe ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure.(33 (3), 485) Recryst. fissures, reaching depths of perhaps 100 m, had initial fractures near time of solidification of top portion of magma chamber, while still hot (<< 1600 ^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, rain water, stream flow over granite surface, partial coverage by ocean, etc., during P-C ice age -- when region of Wasatch Range existed at sea level, S.L. Valley being covered entrely by ocean water and region of Wasatch Boul. rising gently above Pac. Ocean to elev. of possibly 500-1000 ft, say, at a dist. of 10-15 mi to e, as implied by Chinese Wall of limestone on Grandeur Pk, another in Neff's Canyon running e from n ridge of her 9200 ft saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w., in S.L. Valley. This existed prior to regional uplift (of similar topog.) of over 4000 ft. Details of how earthquake waves form an

  3. Recrystallized Granite Surface Fissures Of The Wasatch Range, Produced Not Later Than 1/4 Billion Years Ago

    NASA Astrophysics Data System (ADS)

    McDonald, Keith L.

    2000-05-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, namely, Mount Tuscarora-Wolverine-Millicent,^1,6,7 Bonanza Peak-Midway,^2 Little Cottonwood Canyon and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atmosphere interface, establish that they resulted from high thermal gradients rather than passages of earthquake waves. Magma chambers formed, solidified during Permo-Caroniferous Ice Age(roughly, 1/3...1/4 billion yr ago, a time interval preceding period of extrusion of Rocky Mountains, 10^8 yr ago), and while fluid, belched lava flows^5 extending over its reservoir walls to run hundred of meters. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock^7 to reach Earth's surface so that a pluton containing large amounts of dross(Fe-ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure.^3 Such recrystallized fissures, reaching depths of perhaps 100 m, have initial fractures near time of solidification of their uppermost portion of magma chamber while still hot(<= 1600^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, cold water contacts due to rain, stream flow over granite surface, partial coverage by ocean, etc., wherever heat sinks might occur, during P-C ice age--when region of Wasatch Range existed at sea level, Salt Lake Valley being covered entirely by ocean water and region east of Wasatch Bouleuard rising gently above Pacific Ocean to elevations of possibly 500-1000 ft, say, at a distance of 10-15 mi to east. This fact is implied by Chinese Wall of white limestone on Grandeur Peak, unequivocally, and similarly another in Neff's Canyon running e. from n. ridge of 9200 ft. saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w., in Salt Lake Valley. This existed prior to regional

  4. State Funds for Higher Education Total $34-Billion; 11-Pct. Biennial Rise Equals Lowest in 29 Years.

    ERIC Educational Resources Information Center

    Jaschik, Scott

    1987-01-01

    Tight state budgets and regional economic difficulties have prompted a sharp drop in the rate that state appropriations for higher education have increased over the past two years. New England fares well while farm and oil states suffer. (MLW)

  5. Fourteen characteristics of effective leaders in dentistry.

    PubMed

    Christensen, Gordon J

    2004-01-01

    Leadership can be learned, especially through careful observation of effective leaders. Fourteen characteristics of effective leaders in the dental office and in organized dentistry are discussed. These include: positive mental attitude, faith, goals in life, organization, time management, interdependency and synergy, consistency, communication, self-renewal, empathy and humility, creativity, personal responsibility and drive, ability to say no, and charisma. PMID:15948488

  6. Two-phase increase in the maximum size of life over 3.5 billion years reflects biological innovation and environmental opportunity

    PubMed Central

    Payne, Jonathan L.; Boyer, Alison G.; Brown, James H.; Finnegan, Seth; Kowalewski, Michał; Krause, Richard A.; Lyons, S. Kathleen; McClain, Craig R.; McShea, Daniel W.; Novack-Gottshall, Philip M.; Smith, Felisa A.; Stempien, Jennifer A.; Wang, Steve C.

    2009-01-01

    The maximum size of organisms has increased enormously since the initial appearance of life >3.5 billion years ago (Gya), but the pattern and timing of this size increase is poorly known. Consequently, controls underlying the size spectrum of the global biota have been difficult to evaluate. Our period-level compilation of the largest known fossil organisms demonstrates that maximum size increased by 16 orders of magnitude since life first appeared in the fossil record. The great majority of the increase is accounted for by 2 discrete steps of approximately equal magnitude: the first in the middle of the Paleoproterozoic Era (≈1.9 Gya) and the second during the late Neoproterozoic and early Paleozoic eras (0.6–0.45 Gya). Each size step required a major innovation in organismal complexity—first the eukaryotic cell and later eukaryotic multicellularity. These size steps coincide with, or slightly postdate, increases in the concentration of atmospheric oxygen, suggesting latent evolutionary potential was realized soon after environmental limitations were removed. PMID:19106296

  7. From the Cover: Sulfur isotopes of organic matter preserved in 3.45-billion-year-old stromatolites reveal microbial metabolism

    NASA Astrophysics Data System (ADS)

    Bontognali, Tomaso R. R.; Sessions, Alex L.; Allwood, Abigail C.; Fischer, Woodward W.; Grotzinger, John P.; Summons, Roger E.; Eiler, John M.

    2012-09-01

    The 3.45-billion-year-old Strelley Pool Formation of Western Australia preserves stromatolites that are considered among the oldest evidence for life on Earth. In places of exceptional preservation, these stromatolites contain laminae rich in organic carbon, interpreted as the fossil remains of ancient microbial mats. To better understand the biogeochemistry of these rocks, we performed microscale in situ sulfur isotope measurements of the preserved organic sulfur, including both Δ33S and . This approach allows us to tie physiological inference from isotope ratios directly to fossil biomass, providing a means to understand sulfur metabolism that is complimentary to, and independent from, inorganic proxies (e.g., pyrite). Δ33S values of the kerogen reveal mass-anomalous fractionations expected of the Archean sulfur cycle, whereas values show large fractionations at very small spatial scales, including values below -15‰. We interpret these isotopic patterns as recording the process of sulfurization of organic matter by H2S in heterogeneous mat pore-waters influenced by respiratory S metabolism. Positive Δ33S anomalies suggest that disproportionation of elemental sulfur would have been a prominent microbial process in these communities.

  8. Spend Billions and They Will Come

    ERIC Educational Resources Information Center

    Fox, Bette-Lee

    2004-01-01

    People look at one billion dollars in one of two ways: if it is the result of the long, hard effort of years of fundraising, they rejoice; if it signifies an astronomical budget deficit, they cringe. How, then, should people respond as a community to reaching the $1 billion mark ($1,242,436,438, to be exact) in this year's spending for public…

  9. Lamellar magnetism and exchange bias in billion-year-old titanohematite with nanoscale ilmenite exsolution lamellae: I. mineral and magnetic characterization

    NASA Astrophysics Data System (ADS)

    McEnroe, S. A.; Robinson, Peter; Miyajima, Nobuyoshi; Fabian, Karl; Dyar, Darby; Sklute, Elizabeth

    2016-04-01

    Recent high-resolution aeromagnetic surveys in South Norway have revealed numerous remanent anomalies over Mesoproterozoic metamorphic rocks. Studies on the nature of the minerals that are the remanent carriers has led to discoveries of titanohematite samples with unusual magnetic properties caused by nanoscale exsolution lamellae with their related lamellar magnetism. Here we focus on a rock unit dominated by quartz-plagioclase-biotite granulite containing titanohematite grains with a strong lattice-preferred orientation parallel to regional foliation. When samples with their natural remanent magnetization (NRM), acquired nearly 1 billion years ago, are cooled to 10 K and hysteresis loops measured, these loops show bi-modal exchange bias caused by the magnetism induced within the ilmenite by antiferromagnetic coupling with the adjacent lamellar NRM. By contrast when the samples are cooled in a strong magnetic field (1.5 Tesla), this results in unimodal lamellar magnetism, and, below the TN of ilmenite it adopts a consistent negative orientation, giving rise to unimodal negative exchange bias of >500 mT. The results presented here cover the chemical and magnetic properties, Mossbauer results and transmission electron microscopy of the titanohematite and ilmenite lamellae. Initial magnetic experiments indicated the shifts found in the exchange-bias experiments were directly related to the orientation of the sample to the applied field and the initial state of the NRM. In most samples with these unusual magnetic properties, ilmenite lamellae could not be seen in an optical or a scanning electron microscope. However magnetic experiments gave proof of the presence of ilmenite, later confirmed by Mössbauer spectroscopy. Several attempts were made to identify ilmenite in TEM studies, finally successful in showing ilmenite lamellae parallel to (001) of hematite with thicknesses ˜1.2 to 1.7 nm and aspect ratios 7-13. Here we compare new TEM images and the magnetic

  10. Stable Isotope Geochemistry of Extremely Well-Preserved 2.45-Billion-Year-Old Hydrothermal Systems in the Vetreny Belt, Baltic Shield: Insights into Paleohydrosphere

    NASA Astrophysics Data System (ADS)

    Zakharov, D. O.; Bindeman, I. N.

    2015-12-01

    The early Paleoproterozoic was an eventful period in the Earth's history. The first portions of free oxygen emerged in the atmosphere, Snowball Earth glaciations happened several times and the first supercontinent broke up due to extensive rifting. These events should have affected the stable isotopic composition of the hydrosphere. In this study, we use rocks that were altered in underwater hydrothermal systems to investigate the stable isotopic composition of the hydrosphere 2.39-2.45 billion years ago (hereinafter, Ga). Extremely low-δ18O (down to -27.5‰ SMOW) rocks from 2.39 Ga metamorphosed subglacial hydrothermal systems of the Belomorian belt, Baltic Shield formed at near-equatorial latitudes suggesting a Snowball (or Slushball) Earth glaciation. These results motivated us to look at temporally and geographically close hydrothermal systems from the unmetamorhposed 2.45 Ga Vetreny Belt rift. The length of the rift is 250 km and it is composed of high-Mg basalts, mafic-ultramafic intrusions and sedimentary successions. We examined several localities of high-Mg basalt flows that include astonishingly fresh pillow lavas, often with preserved volcanic glass, eruptive breccias, and hydrothermal alteration zones. Collected samples serve a great textural evidence of water-rock interaction that occurred in situ while basalts were cooling. The preliminary results from coexisting quartz and epidote (T, D18O=311°C), and from coexisting calcite and quartz (T, D18O=190°C) yield values of δ18O of involved water between -1.6 and -0.9 ‰. The values of δ13C in calcites vary between -4.0 and -2.3 ‰. It is likely that hydrothermal fluids operated in the Vetreny Belt rift were derived from seawater that is no different from modern oceanic water in terms of δ18O. Apparently, the rift was a Paleoproterozoic analog of the modern Red Sea, filled with oceanic water. The result is important because the Vetreny Belt rift predates the onset of Snowball Earth glaciation at 2

  11. Lamellar magnetism and exchange bias in billion-year-old titanohematite with nanoscale ilmenite exsolution lamellae: I. Mineral and magnetic characterization

    NASA Astrophysics Data System (ADS)

    McEnroe, Suzanne A.; Robinson, Peter; Miyajima, Nobuyoshi; Fabian, Karl; Dyar, Darby; Sklute, Elizabeth

    2016-07-01

    Recent high-resolution aeromagnetic surveys in South Norway have revealed numerous remanent anomalies over Mesoproterozoic metamorphic rocks. Studies on the nature of the minerals that are the remanent carriers has led to discoveries of titanohematite samples with unusual magnetic properties caused by nanoscale exsolution lamellae with their related lamellar magnetism. Here we focus on a rock unit dominated by quartz-plagioclase-biotite granulite containing titanohematite grains with a strong lattice-preferred orientation parallel to regional foliation. When samples with their natural remanent magnetization (NRM), acquired nearly 1 billion years ago, are cooled to 10 K and hysteresis loops measured, these loops show bi-modal exchange bias caused by the magnetism induced within the ilmenite by antiferromagnetic coupling with the adjacent lamellar NRM. By contrast when the samples are cooled in a strong magnetic field (1.5 Tesla), this results in unimodal lamellar magnetism, and, below the TN of ilmenite it adopts a consistent negative orientation, giving rise to unimodal negative exchange bias of >500 mT. The results presented here cover the chemical and magnetic properties, Mossbauer results and transmission electron microscopy of the titanohematite and ilmenite lamellae. Initial magnetic experiments indicated the shifts found in the exchange-bias experiments were directly related to the orientation of the sample to the applied field and the initial state of the NRM. In most samples with these unusual magnetic properties, ilmenite lamellae could not be seen in an optical or a scanning electron microscope. However magnetic experiments gave proof of the presence of ilmenite, later confirmed by Mössbauer spectroscopy. Several attempts were made to identify ilmenite in TEM studies, finally successful in showing ilmenite lamellae parallel to (001) of hematite with thicknesses ˜1.2 to 1.7 nm and aspect ratios 7-13. Here we compare new TEM images and the magnetic

  12. GPM Science Status Fourteen Months after Launch

    NASA Astrophysics Data System (ADS)

    Skofronick Jackson, Gail; Huffman, George

    2015-04-01

    Water is fundamental to life on Earth. Knowing where and how much rain and snow falls globally is vital to understanding how weather and climate impact both our environment and Earth's water and energy cycles, including effects on agriculture, fresh water availability, and responses to natural disasters. The Global Precipitation Measurement (GPM) Mission, launched February 27, 2014, is an international satellite mission to unify and advance precipitation measurements from a constellation of research and operational sensors to provide "next-generation" precipitation products. The joint NASA-JAXA GPM Core Observatory serves as the cornerstone and anchor to unite the constellation radiometers. The GPM Core Observatory carries a Ku/Ka-band Dual-frequency Precipitation Radar (DPR) and a multi-channel (10-183 GHz) GPM Microwave Radiometer (GMI). Furthermore, since light rain and falling snow account for a significant fraction of precipitation occurrence in middle and high latitudes, the GPM instruments extend the capabilities of the TRMM sensors to detect falling snow, measure light rain, and provide, for the first time, quantitative estimates of microphysical properties of precipitation particles. As a science mission with integrated application goals, GPM is designed to (1) advance precipitation measurement capability from space through combined use of active and passive microwave sensors, (2) advance the knowledge of the global water/energy cycle and freshwater availability through better description of the space-time variability of global precipitation, and (3) improve weather, climate, and hydrological prediction capabilities through more accurate and frequent measurements of instantaneous precipitation rates and time-integrated rainfall accumulation. Since launch, the instruments have been collecting outstanding precipitation data. New scientific insights resulting from these fourteen months of GPM data, an overview of the GPM mission concept and science activities

  13. Medicare Spends Billions on Chronic Kidney Disease, Study Finds

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_158020.html Medicare Spends Billions on Chronic Kidney Disease, Study Finds ... affects nearly 14 percent of Americans and costs Medicare billions of dollars a year, a new study ...

  14. Fourteen Years of Bt Cotton Advances IPM in Arizona

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pink bollworm, Pectinophora gossypiella (Saunders) first invaded Arizona in 1926 and has been a key pest of cotton since the early 1960’s. A broad range of tactics have been developed to manage this pest including a variety of cultural methods, mating disruption via pheromones, sterile insect re...

  15. 29 CFR 570.119 - Fourteen-year minimum.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS CHILD LABOR REGULATIONS, ORDERS AND STATEMENTS OF INTERPRETATION General Statements of Interpretation of the Child Labor Provisions of the Fair Labor Standards Act of 1938, as Amended Oppressive Child Labor § 570.119...

  16. Nine billion or bust?

    NASA Astrophysics Data System (ADS)

    nerd, nerd; Pepperday, Mike; Szautner, a. a. z.

    2014-02-01

    In reply to a review of Tony Ryan and Steve McKevitt's book Project Sunshine, which explores ways in which the Earth could support a future population of nine billion people (Letting the sunshine in, November 2013 pp50-51, http://ow.ly/r0FTM).

  17. ANALYSIS OF CARBON MONOXIDE EXPOSURE FOR FOURTEEN CITIES USING HAPEM-MS3 (FINAL TECHNICAL REPORT)

    EPA Science Inventory

    This report describes results and findings of applying the Hazardous Air Pollutant Exposure Model (HAPEM) for mobile sources, Version 3. This version is formally known as HAPEM-MS3. The application is to fourteen urban areas for calendar year 1990. The urban areas modeled inclu...

  18. Where Have All the Billions Gone?

    ERIC Educational Resources Information Center

    Leask, Linda; And Others

    1987-01-01

    Providing a basis to help Alaskans determine future spending levels and priorities, this report traces how the state spent more than $26 billion in general funds from fiscal years 1981 through 1986 before oil prices crashed and brought state revenues tumbling down with them. Figures indicate that cumulative general fund expenditures over the…

  19. Ultra-dense billion year memory chip

    SciTech Connect

    2009-01-01

    This video shows an iron nanoparticle shuttle moving through a carbon nanotube in the presence of a low voltage electrical current. The shuttles position inside the tube can function as a high-density nonvolatile memory element. (Courtesy of /Zettl Research Group, Lawrence Berkeley National Laboratory and University of California at Berkeley.)

  20. Palaeoclimates: the first two billion years

    PubMed Central

    Kasting, James F; Ono, Shuhei

    2006-01-01

    Earth's climate during the Archaean remains highly uncertain, as the relevant geologic evidence is sparse and occasionally contradictory. Oxygen isotopes in cherts suggest that between 3.5 and 3.2 Gyr ago (Ga) the Archaean climate was hot (55–85 °C); however, the fact that these cherts have experienced only a modest amount of weathering suggests that the climate was temperate, as today. The presence of diamictites in the Pongola Supergroup and the Witwatersrand Basin of South Africa suggests that by 2.9 Ga the climate was glacial. The Late Archaean was relatively warm; then glaciation (possibly of global extent) reappeared in the Early Palaeoproterozoic, around 2.3–2.4 Ga. Fitting these climatic constraints with a model requires high concentrations of atmospheric CO2 or CH4, or both. Solar luminosity was 20–25% lower than today, so elevated greenhouse gas concentrations were needed just to keep the mean surface temperature above freezing. A rise in O2 at approximately 2.4 Ga, and a concomitant decrease in CH4, provides a natural explanation for the Palaeoproterozoic glaciations. The Mid-Archaean glaciations may have been caused by a drawdown in H2 and CH4 caused by the origin of bacterial sulphate reduction. More work is needed to test this latter hypothesis. PMID:16754607

  1. Palaeoclimates: the first two billion years.

    PubMed

    Kasting, James F; Ono, Shuhei

    2006-06-29

    Earth's climate during the Archaean remains highly uncertain, as the relevant geologic evidence is sparse and occasionally contradictory. Oxygen isotopes in cherts suggest that between 3.5 and 3.2 Gyr ago (Ga) the Archaean climate was hot (55-85 degrees C); however, the fact that these cherts have experienced only a modest amount of weathering suggests that the climate was temperate, as today. The presence of diamictites in the Pongola Supergroup and the Witwatersrand Basin of South Africa suggests that by 2.9 Ga the climate was glacial. The Late Archaean was relatively warm; then glaciation (possibly of global extent) reappeared in the Early Palaeoproterozoic, around 2.3-2.4 Ga. Fitting these climatic constraints with a model requires high concentrations of atmospheric CO2 or CH4, or both. Solar luminosity was 20-25% lower than today, so elevated greenhouse gas concentrations were needed just to keep the mean surface temperature above freezing. A rise in O2 at approximately 2.4 Ga, and a concomitant decrease in CH4, provides a natural explanation for the Palaeoproterozoic glaciations. The Mid-Archaean glaciations may have been caused by a drawdown in H2 and CH4 caused by the origin of bacterial sulphate reduction. More work is needed to test this latter hypothesis. PMID:16754607

  2. Four billion people facing severe water scarcity.

    PubMed

    Mekonnen, Mesfin M; Hoekstra, Arjen Y

    2016-02-01

    Freshwater scarcity is increasingly perceived as a global systemic risk. Previous global water scarcity assessments, measuring water scarcity annually, have underestimated experienced water scarcity by failing to capture the seasonal fluctuations in water consumption and availability. We assess blue water scarcity globally at a high spatial resolution on a monthly basis. We find that two-thirds of the global population (4.0 billion people) live under conditions of severe water scarcity at least 1 month of the year. Nearly half of those people live in India and China. Half a billion people in the world face severe water scarcity all year round. Putting caps to water consumption by river basin, increasing water-use efficiencies, and better sharing of the limited freshwater resources will be key in reducing the threat posed by water scarcity on biodiversity and human welfare. PMID:26933676

  3. Four billion people facing severe water scarcity

    PubMed Central

    Mekonnen, Mesfin M.; Hoekstra, Arjen Y.

    2016-01-01

    Freshwater scarcity is increasingly perceived as a global systemic risk. Previous global water scarcity assessments, measuring water scarcity annually, have underestimated experienced water scarcity by failing to capture the seasonal fluctuations in water consumption and availability. We assess blue water scarcity globally at a high spatial resolution on a monthly basis. We find that two-thirds of the global population (4.0 billion people) live under conditions of severe water scarcity at least 1 month of the year. Nearly half of those people live in India and China. Half a billion people in the world face severe water scarcity all year round. Putting caps to water consumption by river basin, increasing water-use efficiencies, and better sharing of the limited freshwater resources will be key in reducing the threat posed by water scarcity on biodiversity and human welfare. PMID:26933676

  4. The nonprofit sector's $100 billion opportunity.

    PubMed

    Bradley, Bill; Jansen, Paul; Silverman, Les

    2003-05-01

    Imagine what an extra $100 billion a year could do for philanthropic and other nonprofit institutions. According to a new study, the nonprofit sector could free that amount--maybe even more--by making five changes in the way it operates. The study asked two central questions: Does the sector's money flow from its source to its ultimate use as efficiently and effectively as possible? If not, where are the big opportunities to increase social benefit? According to former senator Bill Bradley and McKinsey's Paul Jansen and Les Silverman, nonprofits could save roughly $25 billion a year by changing the way they raise funds. By distributing funds more quickly, they could put an extra $30 billion to work. Organizations could generate more than $60 billion a year by streamlining and restructuring the way in which they provide services and by reducing administrative costs. And they could free up even more money--an amount impossible to estimate--by better allocating funds among service providers. The authors admit that making those changes won't be easy. The nonprofit world, historically seen as a collection of locally focused charities, has become an enormous sector, but it lacks the managerial processes and incentives that help keep the for-profit world on track. And when the baby boomers start to retire in less than a decade, public budgets will be squeezed even more than they are today. If the nonprofit sector is to help the nation cope with the stresses ahead, it must become more efficient and challenge its traditional concepts of stewardship. PMID:12747166

  5. Congress Gives Colleges a Billion-Dollar Bonanza.

    ERIC Educational Resources Information Center

    Brainard, Jeffrey; Southwick, Ron

    2000-01-01

    Reports that Congress has earmarked a record amount of money (more than $1 billion) for projects involving specific colleges in the 2000 fiscal year. Notes that such "pork-barrel" spending has tripled since 1996. Charts show trends in earmarks since 1989, year 2000 earmarks by agency, the top 20 recipients of earmarked grants, and ranking of…

  6. Endemic Cardiovascular Diseases of the Poorest Billion.

    PubMed

    Kwan, Gene F; Mayosi, Bongani M; Mocumbi, Ana O; Miranda, J Jaime; Ezzati, Majid; Jain, Yogesh; Robles, Gisela; Benjamin, Emelia J; Subramanian, S V; Bukhman, Gene

    2016-06-14

    The poorest billion people are distributed throughout the world, though most are concentrated in rural sub-Saharan Africa and South Asia. Cardiovascular disease (CVD) data can be sparse in low- and middle-income countries beyond urban centers. Despite this urban bias, CVD registries from the poorest countries have long revealed a predominance of nonatherosclerotic stroke, hypertensive heart disease, nonischemic and Chagas cardiomyopathies, rheumatic heart disease, and congenital heart anomalies, among others. Ischemic heart disease has been relatively uncommon. Here, we summarize what is known about the epidemiology of CVDs among the world's poorest people and evaluate the relevance of global targets for CVD control in this population. We assessed both primary data sources, and the 2013 Global Burden of Disease Study modeled estimates in the world's 16 poorest countries where 62% of the population are among the poorest billion. We found that ischemic heart disease accounted for only 12% of the combined CVD and congenital heart anomaly disability-adjusted life years (DALYs) in the poorest countries, compared with 51% of DALYs in high-income countries. We found that as little as 53% of the combined CVD and congenital heart anomaly burden (1629/3049 DALYs per 100 000) was attributed to behavioral or metabolic risk factors in the poorest countries (eg, in Niger, 82% of the population among the poorest billion) compared with 85% of the combined CVD and congenital heart anomaly burden (4439/5199 DALYs) in high-income countries. Further, of the combined CVD and congenital heart anomaly burden, 34% was accrued in people under age 30 years in the poorest countries, while only 3% is accrued under age 30 years in high-income countries. We conclude although the current global targets for noncommunicable disease and CVD control will help diminish premature CVD death in the poorest populations, they are not sufficient. Specifically, the current framework (1) excludes deaths of

  7. Human fatalities from wild elephant attacks--a study of fourteen cases.

    PubMed

    Das, Sobhan Kr; Chattopadhyay, Saurabh

    2011-05-01

    Human-wild elephant conflicts are frequently reported from various parts of the country. Encroaching of animal habitat by human civilization is a primary reason for this. The present study comprises of fourteen autopsy cases conducted at the department of Forensic Medicine, B.S Medical College, Bankura, West Bengal, India over a period of three years. The study attempts to find out the nature of injuries caused by wild elephant attack and the common factors contributing to human-wild elephant conflict so that vulnerable population can be cautioned to avoid conflicts. A distinct seasonal as well as diurnal variation of attack incidences was noted. Attacks were sudden and unprovoked. Killer elephants were wild tuskers in all the cases. Victims were from the low socioeconomic group and the cause of death was due to trampling on the vital organs like chest and head. PMID:21550563

  8. Colleges' Billion-Dollar Campaigns Feel the Economy's Sting

    ERIC Educational Resources Information Center

    Masterson, Kathryn

    2009-01-01

    The economy's collapse has caught up with the billion-dollar campaign. In the past 12 months, the amount of money raised by a dozen of the colleges engaged in higher education's biggest fund-raising campaigns fell 32 percent from the year before. The decline, which started before the worst of the recession, has forced colleges to postpone…

  9. Life with Four Billion Atoms

    SciTech Connect

    Knight, Thomas

    2013-04-10

    Today it is commonplace to design and construct single silicon chips with billions of transistors. These are complex systems, difficult (but possible) to design, test, and fabricate. Remarkably, simple living systems can be assembled from a similar number of atoms, most of them in water molecules. In this talk I will present the current status of our attempts at full understanding and complexity reduction of one of the simplest living systems, the free-living bacterial species Mesoplasma florum. This 400 nm diameter cell thrives and replicates every 40 minutes with a genome of only 800 kilobases. Our recent experiments using transposon gene knockouts identified 354 of 683 annotated genes as inessential in laboratory culture when inactivated individually. While a functional redesigned genome will certainly not remove all of those genes, this suggests that roughly half the genome can be removed in an intentional redesign. I will discuss our recent knockout results and methodology, and our future plans for Genome re-engineering using targeted knock-in/knock-out double recombination; whole cell metabolic models; comprehensive whole cell metabolite measurement techniques; creation of plug-and-play metabolic modules for the simplified organism; inherent and engineered biosafety control mechanisms. This redesign is part of a comprehensive plan to lay the foundations for a new discipline of engineering biology. Engineering biological systems requires a fundamentally different viewpoint from that taken by the science of biology. Key engineering principles of modularity, simplicity, separation of concerns, abstraction, flexibility, hierarchical design, isolation, and standardization are of critical importance. The essence of engineering is the ability to imagine, design, model, build, and characterize novel systems to achieve specific goals. Current tools and components for these tasks are primitive. Our approach is to create and distribute standard biological parts

  10. Countdown to Six Billion Teaching Kit.

    ERIC Educational Resources Information Center

    Zero Population Growth, Inc., Washington, DC.

    This teaching kit features six activities focused on helping students understand the significance of the world population reaching six billion for our society and our environment. Featured activities include: (1) History of the World: Part Six Billion; (2) A Woman's Place; (3) Baby-O-Matic; (4) Earth: The Apple of Our Eye; (5) Needs vs. Wants; and…

  11. Eight billion asteroids in the Oort cloud

    NASA Astrophysics Data System (ADS)

    Shannon, Andrew; Jackson, Alan P.; Veras, Dimitri; Wyatt, Mark

    2015-01-01

    The Oort cloud is usually thought of as a collection of icy comets inhabiting the outer reaches of the Solar system, but this picture is incomplete. We use simulations of the formation of the Oort cloud to show that ˜4 per cent of the small bodies in the Oort cloud should have formed within 2.5 au of the Sun, and hence be ice-free rock-iron bodies. If we assume that these Oort cloud asteroids have the same size distribution as their cometary counterparts, the Large Synoptic Survey Telescope should find roughly a dozen Oort cloud asteroids during 10 years of operations. Measurement of the asteroid fraction within the Oort cloud can serve as an excellent test of the Solar system's formation and dynamical history. Oort cloud asteroids could be of particular concern as impact hazards as their high mass density, high impact velocity, and low visibility make them both hard to detect and hard to divert or destroy. However, they should be a rare class of object, and we estimate globally catastrophic collisions should only occur about once per billion years.

  12. Initial Costs vs. Operational Costs. A Study of Building Improvement Projects in Fourteen Schools in the School District of Greenville County, South Carolina.

    ERIC Educational Resources Information Center

    Chan, Tak Cheung

    To determine whether initial facility improvement costs were paid back by the reduced operational costs resulting from the improvement projects, this study examined the relationship between initial costs and operational costs of fourteen school buildings improved during the 1978-79 school year in Greenville County, South Carolina. With energy…

  13. Thermal Transfer Compared To The Fourteen Other Imaging Technologies

    NASA Astrophysics Data System (ADS)

    O'Leary, John W.

    1989-07-01

    A quiet revolution in the world of imaging has been underway for the past few years. The older technologies of dot matrix, daisy wheel, thermal paper and pen plotters have been increasingly displaced by laser, ink jet and thermal transfer. The net result of this revolution is improved technologies that afford superior imaging, quiet operation, plain paper usage, instant operation, and solid state components. Thermal transfer is one of the processes that incorporates these benefits. Among the imaging application for thermal transfer are: 1. Bar code labeling and scanning. 2. New systems for airline ticketing, boarding passes, reservations, etc. 3. Color computer graphics and imaging. 4. Copying machines that copy in color. 5. Fast growing communications media such as facsimile. 6. Low cost word processors and computer printers. 7. New devices that print pictures from video cameras or television sets. 8. Cameras utilizing computer chips in place of film.

  14. Thyroid Follicular Carcinoma in a Fourteen-year-old Girl with Graves’ Disease

    PubMed Central

    Kojima-Ishii, Kanako; Ihara, Kenji; Ohkubo, Kazuhiro; Matsuo, Terumichi; Toda, Naoko; Yamashita, Hiroyuki; Kono, Shinji; Hara, Toshiro

    2014-01-01

    Abstract Here we present the case of a 14-yr-old girl who developed thyroid follicular carcinoma accompanied by Graves’ disease. She was diagnosed with Graves’ disease at 10 yr of age and soon achieved a euthyroid state after starting treatment. When she was 13 yr of age, her hyperthyroidism and goiter worsened despite medical therapy. Multiple nodules were found in her enlarged thyroid gland by ultrasonography. Her serum Tg level seemed within the normal range. She underwent near-total thyroidectomy for control of thyroid function. Histopathological study demonstrated that multiple oxyphilic follicular neoplasms were surrounded by the thyroid tissue compatible with Graves’ disease. Capsular invasion was identified in one of the nodules, and thus the histological diagnosis was minimally invasive follicular carcinoma. She did not have signs suggesting metastasis, and has had no relapse for 18 mo after the operation. Although some previous studies showed a high prevalence of thyroid cancer with an aggressive nature in adult patients with Graves’ disease, few reports about thyroid cancer accompanied by Graves’ disease are available in children. The present case, however, suggests that careful investigation is needed when we detect thyroid nodules or progressive thyroid enlargement, especially in children with Graves’ disease. PMID:24790388

  15. Semiclosed thromboendoarterectomy on femoro-popliteal tract revisited after a fourteen years experience on 595 cases.

    PubMed

    Vercellio, G; Castelli, P; Coletti, M; Carlesi, R; Agrifoglio, G

    1986-01-01

    In the seventies atherosclerotic femoropopliteal lesions were extensively treated by means of retrograde semiclosed thromboendarterectomy (FP-TEA) an analytic follow-up of cases, until 1980, induced the modification of the indications to FP-TEA. Currently the FP-TEA technique is only employed for patients at the 2nd Fontaine's stage with disabling claudication (generally less than 100 mt) with a good distal run-off (at least 2 tibial vessels patent). The report deals with a series of 595 cases operated in the period January 1971-December 1984. In 45% of cases FP-TEA was associated with a proximal revascularization. In an attempt to focus on the factors that may influence the outcome, the patients operated in 1976, 1980, 1984, were assessed and the results related to clinical stage, angiographic pattern and postoperative treatment. PMID:3721758

  16. Herbicide treatment effects on properties of mountain big sagebrush soils after fourteen years

    NASA Technical Reports Server (NTRS)

    Burke, I. C.; Reiners, W. A.; Sturges, D. L.; Matson, P. A.

    1987-01-01

    The effects of sagebrush conversion on the soil properties of a high-elevation portion of the Western Intermountain Sagebrush Steppe (West, 1983) are described. Changes were found in only a few soil chemical properties after conversion to grassland. It was found that surface concentrations of N were lower under grass vegetation than under undisturbed vegetation. Undershrub net N mineralization rates were higher under shrubs in the sagebrush vegetation than under former shrubs in the grass vegetation.

  17. The Women's Life-Paths Study: Role-Innovation over Fourteen Years. Symposium Papers.

    ERIC Educational Resources Information Center

    Tangri, Sandra S.; And Others

    Four symposium papers report the results of a longitudinal study of career development and life changes for a sample of 1,967 female college graduates in the Michigan Student Study who were studied in 1967, 1970 and 1981. The first of the papers, entitled "Where Are They Now? Career Outcomes for the Original Role-Innovators," by Sandra S. Tangri,…

  18. A Billion Is How Big?

    ERIC Educational Resources Information Center

    Gough, John

    2008-01-01

    Place-value is a central, powerful mathematical concept. From the earliest years of school, students focus on developing strong understanding of the ideas, notation and computational use. Many times, however, they get as far as thousands and then resort to waving their hands--at least until they start a far more advanced and abstract treatment of…

  19. Ubiquitous Supercritical Wing Design Cuts Billions in Fuel Costs

    NASA Technical Reports Server (NTRS)

    2015-01-01

    A Langley Research Center engineer’s work in the 1960s and ’70s to develop a wing with better performance near the speed of sound resulted in a significant increase in subsonic efficiency. The design was shared with industry. Today, Renton, Washington-based Boeing Commercial Airplanes, as well as most other plane manufacturers, apply it to all their aircraft, saving the airline industry billions of dollars in fuel every year.

  20. Gaia: how to map a billion stars with a billion pixels

    NASA Astrophysics Data System (ADS)

    de Bruijne, J. H. J.

    2008-07-01

    Gaia, ESA's ambitious star-mapper mission due for launch late-2011, will provide multi-epoch micro-arcsecond astrometric and milli-magnitude photometric data for the brightest one billion objects in the sky, down to at least magnitude 20. Spectroscopic data will simultaneously be collected for the subset of the brightest 100 million stars, down to about magnitude 17. This massive data volume will allow astronomers to reconstruct the structure, evolution and formation history of the Milky Way. It will also revolutionize studies of the solar system and stellar physics and will contribute to diverse research areas, ranging from extra-solar planets to general relativity. Underlying Gaia's scientific harvest will lie in a Catalogue, built on the fundamental space-based measurements. During the 5-year nominal operational lifetime, Gaia's payload, with its CCD mosaic containing 1 billion pixels, will autonomously detect all objects of interest and observe them throughout their passage of the focal plane. This paper discusses the workings of the Gaia instrument, details its payload, and discusses in depth how the scientific measurements will be collected. It addresses issues like maintenance of the scanning law, on-board data processing, the detection and confirmation of objects (single and multiple stars), the detection and rejection of cosmic rays and solar protons, the fundamental science measurements themselves composed of windows of CCD samples (pixels), and special strategies employed to maximize the science return for moving (i.e., solar-system) objects. The paper also explains how an on-board priority scheme will ensure catalogue completeness down to the faintest magnitudes possible, despite the limited ground-station availability and the enormous data volume that will be sent to the ground.

  1. If 1 in 10 U.S. Smokers Quits, $63 Billion Saved

    MedlinePlus

    ... nih.gov/medlineplus/news/fullstory_158758.html If 1 in 10 U.S. Smokers Quits, $63 Billion Saved ... money. That's because health care costs plummet just one year after stopping, new research shows. A 10 ...

  2. Billion shot flashlamp for spaceborne lasers

    NASA Technical Reports Server (NTRS)

    Richter, Linda; Schuda, Felix; Degnan, John

    1990-01-01

    A billion-shot flashlamp developed under a NASA contract for spaceborne laser missions is presented. Lifetime-limiting mechanisms are identified and addressed. Two energy loadings of 15 and 44 Joules were selected for the initial accelerated life testing. A fluorescence-efficiency test station was used for measuring the useful-light output degradation of the lamps. The design characteristics meeting NASA specifications are outlined. Attention is focused on the physical properties of tungsten-matrix cathodes, the chemistry of dispenser cathodes, and anode degradation. It is reported that out of the total 83 lamps tested in the program, 4 lamps reached a billion shots and one lamp is beyond 1.7 billion shots, while at 44 Joules, 4 lamps went beyond 100 million shots and one lamp reached 500 million shots.

  3. Discovering the Meaning of Unity of Purpose: A Case Study of Fourteen Accelerated Schools.

    ERIC Educational Resources Information Center

    Davidson, Betty M.; Dell, Geralyn L.

    This paper presents findings of a study that examined how teachers restructuring schools came to understand the meaning of the term "unity of purpose." Fourteen Louisiana schools, comprised primarily of high-risk student populations, implemented the accelerated-schools model of restructuring. The accelerated school model is based on three…

  4. Contemporary "Hoisan-wa" Language Maintenance in Northern California: Evidence from Fourteen Frog Story Narratives

    ERIC Educational Resources Information Center

    Leung, Genevieve

    2012-01-01

    This article explores uninvestigated issues in Cantonese and "Hoisan-wa" language maintenance from an ethnic Chinese diaspora point of view. Data come from a larger study looking at Frog Story narratives from 140 Cantonese-English bilingual children in California. Fourteen of these children were found to display uniquely "Hoisan-wa" phonology and…

  5. Spherule beds 3.47-3.24 billion years old in the Barberton Greenstone Belt, South Africa: a record of large meteorite impacts and their influence on early crustal and biological evolution.

    PubMed

    Lowe, Donald R; Byerly, Gary R; Kyte, Frank T; Shukolyukov, Alexander; Asaro, Frank; Krull, Alexandra

    2003-01-01

    Four layers, S1-S4, containing sand-sized spherical particles formed as a result of large meteorite impacts, occur in 3.47-3.24 Ga rocks of the Barberton Greenstone Belt, South Africa. Ir levels in S3 and S4 locally equal or exceed chondritic values but in other sections are at or only slightly above background. Most spherules are inferred to have formed by condensation of impact-produced rock vapor clouds, although some may represent ballistically ejected liquid droplets. Extreme Ir abundances and heterogeneity may reflect element fractionation during spherule formation, hydraulic fractionation during deposition, and/or diagenetic and metasomatic processes. Deposition of S1, S2, and S3 was widely influenced by waves and/or currents interpreted to represent impact-generated tsunamis, and S1 and S2 show multiple graded layers indicating the passage of two or more wave trains. These tsunamis may have promoted mixing within a globally stratified ocean, enriching surface waters in nutrients for biological communities. S2 and S3 mark the transition from the 300-million-year-long Onverwacht stage of predominantly basaltic and komatiitic volcanism to the late orogenic stage of greenstone belt evolution, suggesting that regional and possibly global tectonic reorganization resulted from these large impacts. These beds provide the oldest known direct record of terrestrial impacts and an opportunity to explore their influence on early life, crust, ocean, and atmosphere. The apparent presence of impact clusters at 3.26-3.24 Ga and approximately 2.65-2.5 Ga suggests either spikes in impact rates during the Archean or that the entire Archean was characterized by terrestrial impact rates above those currently estimated from the lunar cratering record. PMID:12804363

  6. Spherule Beds 3.47-3.24 Billion Years Old in the Barberton Greenstone Belt, South Africa: A Record of Large Meteorite Impacts and Their Influence on Early Crustal and Biological Evolution

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    Four layers, S1-S4, containing sand-sized spherical particles formed as a result of large meteorite impacts, occur in 3.47-3.24 Ga rocks of the Barberton Greenstone Belt, South Africa. Ir levels in S3 and S4 locally equal or exceed chondritic values but in other sections are at or only slightly above background. Most spherules are inferred to have formed by condensation of impact-produced rock vapor clouds, although some may represent ballistically ejected liquid droplets. Extreme Ir abundances and heterogeneity may reflect element fractionation during spherule formation, hydraulic fractionation during deposition, and/or diagenetic and metasomatic processes. Deposition of S1, S2, and S3 was widely influenced by waves and/or currents interpreted to represent impact-generated tsunamis, and S1 and S2 show multiple graded layers indicating the passage of two or more wave trains. These tsunamis may have promoted mixing within a globally stratified ocean, enriching surface waters in nutrients for biological communities. S2 and S3 mark the transition from the 300-million-year-long Onverwacht stage of predominantly basaltic and komatiitic volcanism to the late orogenic stage of greenstone belt evolution, suggesting that regional and possibly global tectonic reorganization resulted from these large impacts. These beds provide the oldest known direct record of terrestrial impacts and an opportunity to explore their influence on early life, crust, ocean, and atmosphere. The apparent presence of impact clusters at 3.26-3.24 Ga and approx. 2.65-2.5 Ga suggests either spikes in impact rates during the Archean or that the entire Archean was characterized by terrestrial impact rates above those currently estimated from the lunar cratering record.

  7. Two-billion-year-old nuclear reactors: Nature goes fission

    SciTech Connect

    Curtis, D.B.

    1992-12-31

    Once it was thought that the isotopic composition of natural uranium was invariant. It was thus surprising in 1972 when French scientists observed small but significant deficiencies of the minor isotope {sup 235}U in uranium ore. Subsequent investigations traced the isotopically anomalous material to the Oklo mine in the African Republic of Gabon. In the mine, cubic-dekametre-sized pods of rock were found to contain extraordinary concentrations of uranium, as much as 65%, with as little as half the normal isotopic abundance of {sup 235}U. In these rocks, neodymium was found to be deficient in the premordial isotope {sup 142}Nd and enriched in the fission-produced isotopes {sup 143-150}Nd. The presence of fission products was unambiguous evidence that the {sup 235}U deficiencies were the result of sustained nuclear fission. Within the heart of the natural reactors, the fission densities were on the order of 10{sup 20} fissions/cm{sup 3}, producing hundreds of megajoules of energy and tens of microwatts of power per gram of rock. Nature had forestalled man`s great discovery of energy production by nuclear fission.

  8. The Yatela gold deposit: 2 billion years in the making

    NASA Astrophysics Data System (ADS)

    Hein, K. A. A.; Matsheka, I. R.; Bruguier, O.; Masurel, Q.; Bosch, D.; Caby, R.; Monié, P.

    2015-12-01

    Gold mineralisation in the Yatela Main gold mine is hosted in a saprolitic residuum situated above Birimian supracrustal rocks, and at depth. The supracrustal rocks comprise metamorphosed calcitic and dolomitic marbles that were intruded by diorite (2106 ± 10 Ma, 207Pb/206Pb), and sandstone-siltstone-shale sequences (youngest detrital zircon population dated at 2139 ± 6 Ma). In-situ gold-sulphide mineralisation is associated with hydrothermal activity synchronous to emplacement of the diorite and forms a sub-economic resource; however, the overlying saprolitic residuum hosts economic gold mineralisation in friable lateritized palaeosols and aeolian sands (loess). Samples of saprolitic residuum were studied to investigate the morphology and composition of gold grains as a proxy for distance from source (and possible exploration vector) because the deposit hosts both angular and detrital gold suggesting both proximal and distal sources. U-Pb geochronology of detrital zircons also indicated a proximal and distal source, with the age spectra giving Archaean (2.83-3.28 Ga), and Palaeoproterozoic (1.95-2.20 Ga) to Neoproterozoic (1.1-1.8 Ga) zircons in the Yatela depocentre. The 1.1-1.8 Ga age spectrum restricts the maximum age for the first deposition of the sedimentary units in the Neoproterozoic, or during early deposition in the Taoudeni Basin. Models for formation of the residuum include distal and proximal sources for detritus into the depocentre, however, it is more likely that material was sourced locally and included recycled material. The creation of a deep laterite weathering profile and supergene enrichment of the residuum probably took place during the mid-Cretaceous-early Tertiary.

  9. Teledesic pushes $9-billion, 900-satellite system

    NASA Astrophysics Data System (ADS)

    1994-03-01

    Teledesic Corp. is seeking FCC approval to deploy a communication satellite system, costing $9 billion and using more than 900 satellites in low Earth orbit. This system would provide telephone and broadband data service to remote areas and developing countries. The two major stockholders in Teledesic are William Gates (of Microsoft Corp.) and Craig McCaw (of McCaw Cellular Communications). Each satellite would act as a node in a packet-switching network. The satellites would provide continuous global coverage.

  10. Effects of Fourteen-Day Bed Rest on Trunk Stabilizing Functions in Aging Adults

    PubMed Central

    Sarabon, Nejc; Rosker, Jernej

    2015-01-01

    Bed rest has been shown to have detrimental effects on structural and functional characteristics of the trunk muscles, possibly affecting trunk and spinal stability. This is especially important in populations such as aging adults with often altered trunk stabilizing functions. This study examined the effects of a fourteen-day bed rest on anticipatory postural adjustments and postural reflex responses of the abdominal wall and back muscles in sixteen adult men. Postural activation of trunk muscles was measured using voluntary quick arm movement and sudden arm loading paradigm. Measurements were conducted prior to the bed rest, immediately after, and fourteen days after the bed rest. Immediately after the bed rest, latencies of anticipatory postural adjustments showed significant shortening, especially for the obliquus internus and externus muscles. After a fourteen-day recuperation period, anticipatory postural adjustments reached a near to complete recovery. On the contrary, reactive response latencies increased from pre-bed-rest to both post-bed-rest measurement sessions. Results indicate an important effect of bed rest on stabilizing functions of the trunk muscles in elderly adults. Moreover, there proved to be a significant deterioration of postural reactive responses that outlasted the 14-day post-bed-rest rehabilitation. PMID:26601104

  11. LLNL's Big Science Capabilities Help Spur Over $796 Billion in U.S. Economic Activity Sequencing the Human Genome

    SciTech Connect

    Stewart, Jeffrey S.

    2015-07-28

    LLNL’s successful history of taking on big science projects spans beyond national security and has helped create billions of dollars per year in new economic activity. One example is LLNL’s role in helping sequence the human genome. Over $796 billion in new economic activity in over half a dozen fields has been documented since LLNL successfully completed this Grand Challenge.

  12. Delivering on Obama's renewables promise will cost billions

    SciTech Connect

    2009-04-15

    For wind energy in the eastern half of the U.S., costs would be $50 billion to $80 billion for transmission lines, in addition to the $700 billion to $1.1 trillion to build the wind farms to generate power.

  13. Simulating Billion-Task Parallel Programs

    SciTech Connect

    Perumalla, Kalyan S; Park, Alfred J

    2014-01-01

    In simulating large parallel systems, bottom-up approaches exercise detailed hardware models with effects from simplified software models or traces, whereas top-down approaches evaluate the timing and functionality of detailed software models over coarse hardware models. Here, we focus on the top-down approach and significantly advance the scale of the simulated parallel programs. Via the direct execution technique combined with parallel discrete event simulation, we stretch the limits of the top-down approach by simulating message passing interface (MPI) programs with millions of tasks. Using a timing-validated benchmark application, a proof-of-concept scaling level is achieved to over 0.22 billion virtual MPI processes on 216,000 cores of a Cray XT5 supercomputer, representing one of the largest direct execution simulations to date, combined with a multiplexing ratio of 1024 simulated tasks per real task.

  14. Billions for biodefense: federal agency biodefense funding, FY2001-FY2005.

    PubMed

    Schuler, Ari

    2004-01-01

    Over the past several years, the United States government has spent substantial resources on preparing the nation against a bioterrorist attack. This article analyzes the civilian biodefense funding by the federal government from fiscal years 2001 through 2005, specifically analyzing the budgets and allocations for biodefense at the Department of Health and Human Services, the Department of Homeland Security, the Department of Defense, the Department of Agriculture, the Environmental Protection Agency, the National Science Foundation, and the Department of State. In total, approximately $14.5 billion has been funded for civilian biodefense through FY2004, with an additional $7.6 billion in the President's budget request for FY2005. PMID:15225402

  15. Relations of fine-root morphology on (137)Cs uptake by fourteen Brassica species.

    PubMed

    Aung, Han Phyo; Aye, Yi Swe; Mensah, Akwasi Dwira; Omari, Richard Ansong; Djedidi, Salem; Oikawa, Yosei; Ohkama-Ohtsu, Naoko; Yokoyama, Tadashi; Bellingrath-Kimura, Sonoko Dorothea

    2015-12-01

    Fourteen Brassica species consisting of seven leafy vegetables and seven root vegetables were examined for (137)Cs uptake differences in relation to their fine-root morphological characters. A pot experiment was conducted from November 2014 to February 2015 in a Phytroton using a contaminated soil of Fukushima prefecture. Leafy vegetables showed bigger root diameters, larger root surface area and larger root volume. Consequently, leafy vegetables had higher (137)Cs uptake compared to root vegetables. Among the three fine-root parameters, only root surface area was observed as a significant contributing factor to higher (137)Cs uptake in terms of transfer factor (TF, dry weight basis). Kakina exhibited higher (137)Cs TF value (0.20) followed by Chinese cabbage (0.18) and mizuna (0.17). Lower TF values were observed in turnip (0.059), rutabaga (Kitanoshou) (0.062) and radish (Ha daikon) (0.064). PMID:26355648

  16. Polyphenol content and antioxidant activity of fourteen wild edible fruits from Burkina Faso.

    PubMed

    Lamien-Meda, Aline; Lamien, Charles Euloge; Compaoré, Moussa M Y; Meda, Roland N T; Kiendrebeogo, Martin; Zeba, Boukare; Millogo, Jeanne F; Nacoulma, Odile G

    2008-01-01

    A total of fourteen (14) species of wild edible fruits from Burkina Faso were analyzed for their phenolic and flavonoid contents, and their antioxidant activities using the DPPH, FRAP and ABTS methods. The data obtained show that the total phenolic and total flavonoid levels were significantly higher in the acetone than in the methanol extracts.Detarium microcarpum fruit had the highest phenolic and the highest flavonoid content,followed by that of Adansonia digitata, Ziziphus mauritiana, Ximenia americana and Lannea microcarpa. Significant amounts of total phenolics were also detected in the other fruit species in the following order of decreasing levels: Tamarindus indica > Sclerocaryabirrea > Dialium guineense > Gardenia erubescens > Diospyros mespiliformis > Parkiabiglobosa > Ficus sycomorus > Vitellaria paradoxa. Detarium microcarpum fruit also showed the highest antioxidant activity using the three antioxidant assays. Fruits with high antioxidant activities were also found to possess high phenolic and flavonoid contents. There was a strong correlation between total phenolic and flavonoid levels and antioxidant activities. PMID:18463567

  17. Review of the Berosus Leach of Venezuela (Coleoptera, Hydrophilidae, Berosini) with description of fourteen new species.

    PubMed

    Oliva, Adriana; Short, Andrew E Z

    2012-01-01

    The species of the water scavenger beetle genus Berosus Leach occurring in Venezuela are reviewed. Thirty-six species are recorded, including fifteen new species, fourteen of which are described here as new: Berosus araguasp. n., Berosus asymmetricussp. n., Berosus capanaparosp. n., Berosus castaneussp. n., Berosus corozosp. n., Berosus ebeninussp. n., Berosus garciaisp. n., Berosus humeralissp. n., Berosus jolyisp. n., Berosus llanensissp. n., Berosus megaphallussp. n., Berosus ornaticollissp. n., Berosus repertussp. n., and Berosus tramidrumsp. n. The fifteenth new species, known from a single female, is left undescribed pending the collection of males. Twelve species are recorded from Venezuela for the first time: Berosus ambogynus Mouchamps, Berosus consobrinus Knisch, Berosus elegans Knisch, Berosus geayi d'Orchymont, Berosus ghanicus d'Orchymont, Berosus guyanensis Queney, Berosus holdhausi Knisch, Berosus marquardti Knisch, Berosus olivae Queney, Berosus reticulatus Knisch, Berosus wintersteineri Knisch, and Berosus zimmermanni Knisch. PMID:22811607

  18. Fourteen new species of Heterospilus Haliday (Hymenoptera, Braconidae: Doryctinae) from Brazil.

    PubMed

    Chiletto, Bo; Penteado-Dias, Am

    2016-01-01

    Fourteen new species of the genus Heterospilus Haliday found in semideciduous mesophilic forest areas at São Paulo State, Brazil are described. They are: Heterospilus ayewai sp. n., H. caetetus sp. n., H. fernandesi sp. n., H. fiorelinii sp. n., H. granulosus sp. n., H. homalos sp. n., H. intervalesi sp. n., H. japi sp.n., H. meloi sp. n., H. mesopleuron sp. n., H. periotoi sp. n., H. riveroni sp. n., H. sormusi sp. n., and H. virginensis sp. n. Heterospilus species are characterized by the sculpturation of the vertex: granulate, striate, rugose, or smooth, without sculpturation. All specimens of Heterospilus in this study are in the species group with a smooth, unsculptured vertex. PMID:27470859

  19. Review of the Berosus Leach of Venezuela (Coleoptera, Hydrophilidae, Berosini) with description of fourteen new species

    PubMed Central

    Oliva, Adriana; Short, Andrew E. Z.

    2012-01-01

    Abstract The species of the water scavenger beetle genus Berosus Leach occurring in Venezuela are reviewed. Thirty-six species are recorded, including fifteen new species, fourteen of which are described here as new: Berosus aragua sp. n., Berosus asymmetricus sp. n., Berosus capanaparo sp. n., Berosus castaneus sp. n., Berosus corozo sp. n., Berosus ebeninus sp. n., Berosus garciai sp. n., Berosus humeralis sp. n., Berosus jolyi sp. n., Berosus llanensis sp. n., Berosus megaphallus sp. n., Berosus ornaticollis sp. n., Berosus repertus sp. n., and Berosus tramidrum sp. n. The fifteenth new species, known from a single female, is left undescribed pending the collection of males. Twelve species are recorded from Venezuela for the first time: Berosus ambogynus Mouchamps, Berosus consobrinus Knisch, Berosus elegans Knisch, Berosus geayi d’Orchymont, Berosus ghanicus d’Orchymont, Berosus guyanensis Queney, Berosus holdhausi Knisch, Berosus marquardti Knisch, Berosus olivae Queney, Berosus reticulatus Knisch, Berosus wintersteineri Knisch, and Berosus zimmermanni Knisch. PMID:22811607

  20. Fourteen polymorphic microsatellite markers for the threatened Arnica montana (Asteraceae)1

    PubMed Central

    Duwe, Virginia K.; Ismail, Sascha A.; Buser, Andres; Sossai, Esther; Borsch, Thomas; Muller, Ludo A. H.

    2015-01-01

    • Premise of the study: Microsatellite markers were developed to investigate population genetic structure in the threatened species Arnica montana. • Methods and Results: Fourteen microsatellite markers with di-, tetra-, and hexanucleotide repeat motifs were developed for A. montana using 454 pyrosequencing without and with library-enrichment methods, resulting in 56,545 sequence reads and 14,467 sequence reads, respectively. All loci showed a high level of polymorphism, with allele numbers ranging from four to 11 in five individuals from five populations (25 samples) and an expected heterozygosity ranging from 0.192 to 0.648 across the loci. • Conclusions: This set of microsatellite markers is the first one described for A. montana and will facilitate conservation genetic applications as well as the understanding of phylogeographic patterns in this species. PMID:25606354

  1. Uranium in Canada: A billion dollar industry

    SciTech Connect

    Ruzicka, V. )

    1989-12-01

    In 1988, Canada maintained its position as the world's leading producer of uranium with an output of more than 12,400 MT of uranium in concentrates, worth $1.1 billion Canadian. As domestic requirements represent only 15% of current Canadian production, most of the output was exported. With current implementation of the Canada/US Free Trade Agreement, the US has become Canada's major uranium export customer. With a large share of the world's known uranium resources, Canada remains the focus of international uranium exploration activity. In 1988, the uranium exploration expenditures in Canada exceeded $58 million Canadian. The principal exploration targets were deposits associated with Proterozoic unconformities in Saskatchewan and Northwest Territories, particularly those in the Athabasca and Thelon basin regions of the Canadian Shield. Major attention was also paid to polymetallic deposits in which uranium is associated with precious metals, such as gold and platinum group elements. Conceptual genetic models for these deposit types represent useful tools to guide exploration.

  2. Agroecohydrology: Key to Feeding 9 Billion?

    NASA Astrophysics Data System (ADS)

    Herrick, J.

    2011-12-01

    Agricultural production necessary to feed 9 billion people in 2050 depends on increased production on existing croplands, and expanding onto 'marginal' lands. A high proportion of these lands are marginal because they are too steep or too dry to reliably support crop production. These same characteristics increase their susceptibility to accelerated erosion, leading (for most soil profiles) to further reductions in plant available water as infiltration and soil profile water holding capacity decline. Sustaining production on these marginal lands will require careful land use planning. In this paper, we present a land use planning framework that integrates 4 elements: (1) potential production (based on soil profile characteristics), (2) edaphic, topographic and climatic limitations to production, (3) soil resistance to degradation, and (4) resilience. This framework expands existing land capability classification systems through the integration of biophysical feedbacks and thresholds. State and transition models, similar to those currently applied to rangelands in the United States and other countries, are used to organize and communicate knowledge about the sustainability of different land use changes and management actions at field to regional scales. This framework emphasizes hydrologic characteristics of soil profiles and landscapes over fertility because fertility declines are more easily addressed through increased inputs. The presentation will conclude with a discussion of how research in ecohydrology can be more effectively focused to support sustainable food production in the context of increasingly rapid social and economic changes throughout the world.

  3. NOAA Budget Increases to $4.1 Billion, But Some Key Items Are Reduced

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2008-02-01

    The Bush administration has proposed a US$4.1 billion budget for fiscal year (FY) 2009 for the U.S. National Oceanic and Atmospheric Administration (NOAA). The proposed budget, which would be the agency's largest ever, is $202.6 million, or 5.2%, above the FY 2008 enacted budget. By topping $4 billion and the amount Congress passed for FY 2008, the budget proposal crosses into ``a new threshold,'' according Navy Vice Admiral Conrad Lautenbacher, undersecretary of commerce for oceans and atmosphere and NOAA administrator.

  4. Nitrogen, phosphorus, and potassium requirements to support a multi-billion gallon biofuel industry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To accomplish the goals for biofuel and bioenergy production, 1 billion tons of biomass will need to be produced annually by the year 2030. Crop production data from a joint study by the U.S. Department of Energy (US DOE) and the U.S. Department of Agriculture (USDA) demonstrated how this goal could...

  5. Universities Report $1.8-Billion in Earnings on Inventions in 2011

    ERIC Educational Resources Information Center

    Blumenstyk, Goldie

    2012-01-01

    Universities and their inventors earned more than $1.8-billion from commercializing their academic research in the 2011 fiscal year, collecting royalties from new breeds of wheat, from a new drug for the treatment of HIV, and from longstanding arrangements over enduring products like Gatorade. Northwestern University earned the most of any…

  6. Cancer costs projected to reach at least $158 billion in 2020

    Cancer.gov

    Based on growth and aging of the U.S. population, medical expenditures for cancer in the year 2020 are projected to reach at least $158 billion (in 2010 dollars) – an increase of 27 percent over 2010. If newly developed tools for cancer diagnosis, treatme

  7. US Physician Practices Spend More Than $15.4 Billion Annually To Report Quality Measures.

    PubMed

    Casalino, Lawrence P; Gans, David; Weber, Rachel; Cea, Meagan; Tuchovsky, Amber; Bishop, Tara F; Miranda, Yesenia; Frankel, Brittany A; Ziehler, Kristina B; Wong, Meghan M; Evenson, Todd B

    2016-03-01

    Each year US physician practices in four common specialties spend, on average, 785 hours per physician and more than $15.4 billion dealing with the reporting of quality measures. While much is to be gained from quality measurement, the current system is unnecessarily costly, and greater effort is needed to standardize measures and make them easier to report. PMID:26953292

  8. Economic toll of AIDS put at $10 billion in Canada.

    PubMed

    1996-11-29

    John McCallum, Chief economist at the Royal Bank of Canada, announced that AIDS has cost the nation's economy $10 billion since 1981. These calculations included losses in both direct medical care and human capital. This monetary figure is expected to rise to $36 billion by 2010. An estimated 42,500 to 45,000 Canadians are infected with HIV. PMID:11364044

  9. Evaluation of carcinogenic potential of the herbicide glyphosate, drawing on tumor incidence data from fourteen chronic/carcinogenicity rodent studies.

    PubMed

    Greim, Helmut; Saltmiras, David; Mostert, Volker; Strupp, Christian

    2015-03-01

    Abstract Glyphosate, an herbicidal derivative of the amino acid glycine, was introduced to agriculture in the 1970s. Glyphosate targets and blocks a plant metabolic pathway not found in animals, the shikimate pathway, required for the synthesis of aromatic amino acids in plants. After almost forty years of commercial use, and multiple regulatory approvals including toxicology evaluations, literature reviews, and numerous human health risk assessments, the clear and consistent conclusions are that glyphosate is of low toxicological concern, and no concerns exist with respect to glyphosate use and cancer in humans. This manuscript discusses the basis for these conclusions. Most toxicological studies informing regulatory evaluations are of commercial interest and are proprietary in nature. Given the widespread attention to this molecule, the authors gained access to carcinogenicity data submitted to regulatory agencies and present overviews of each study, followed by a weight of evidence evaluation of tumor incidence data. Fourteen carcinogenicity studies (nine rat and five mouse) are evaluated for their individual reliability, and select neoplasms are identified for further evaluation across the data base. The original tumor incidence data from study reports are presented in the online data supplement. There was no evidence of a carcinogenic effect related to glyphosate treatment. The lack of a plausible mechanism, along with published epidemiology studies, which fail to demonstrate clear, statistically significant, unbiased and non-confounded associations between glyphosate and cancer of any single etiology, and a compelling weight of evidence, support the conclusion that glyphosate does not present concern with respect to carcinogenic potential in humans. PMID:25716480

  10. Evaluation of carcinogenic potential of the herbicide glyphosate, drawing on tumor incidence data from fourteen chronic/carcinogenicity rodent studies

    PubMed Central

    Greim, Helmut; Saltmiras, David; Mostert, Volker; Strupp, Christian

    2015-01-01

    Abstract Glyphosate, an herbicidal derivative of the amino acid glycine, was introduced to agriculture in the 1970s. Glyphosate targets and blocks a plant metabolic pathway not found in animals, the shikimate pathway, required for the synthesis of aromatic amino acids in plants. After almost forty years of commercial use, and multiple regulatory approvals including toxicology evaluations, literature reviews, and numerous human health risk assessments, the clear and consistent conclusions are that glyphosate is of low toxicological concern, and no concerns exist with respect to glyphosate use and cancer in humans. This manuscript discusses the basis for these conclusions. Most toxicological studies informing regulatory evaluations are of commercial interest and are proprietary in nature. Given the widespread attention to this molecule, the authors gained access to carcinogenicity data submitted to regulatory agencies and present overviews of each study, followed by a weight of evidence evaluation of tumor incidence data. Fourteen carcinogenicity studies (nine rat and five mouse) are evaluated for their individual reliability, and select neoplasms are identified for further evaluation across the data base. The original tumor incidence data from study reports are presented in the online data supplement. There was no evidence of a carcinogenic effect related to glyphosate treatment. The lack of a plausible mechanism, along with published epidemiology studies, which fail to demonstrate clear, statistically significant, unbiased and non-confounded associations between glyphosate and cancer of any single etiology, and a compelling weight of evidence, support the conclusion that glyphosate does not present concern with respect to carcinogenic potential in humans. PMID:25716480

  11. [Determination of U, Th and Tl in fourteen Chinese traditional medicines by microwave digestion-ICP-MS].

    PubMed

    Sun, Wei-Min; Xue, Da-Fang; Li, Hong; Liu, Hui; Teng, Wen-Feng

    2009-01-01

    Fourteen Chinese traditional medicines were digested by microwave digestion, which are generally applied to treat tumor in clinic, and the contents of U, Th and Tl in the fourteen Chinese traditional medicines were determined by inductively coupled plasma mass spectrometry (ICP-MS), and the results show that the change ranges of the elements contents were: 0.005 153-0.1534 microg x g(-1) for U; 0.03501-0.4628 microg x g(-1) for Th; 0.00143-1.600 microg x g(-1) for Tl. The contents of U, Th and Tl in the fourteen Chinese traditional medicines were low, and not with one accord. The determination results of the fourteen Chinese traditional medicines were analyzed by SPSS 11.5, and the results show that there were not significant deviations(p>0.05) of the contents of U, Th and Tl between the medicine of treating the toxifying disease with poisonous agents and the medicines of heat-clearing. The study indicates that inductively coupled plasma mass spectrometry (ICP-MS) is a quick, accurate, sensitive method to determine the contents of U, Th and Tl in Chinese traditional medicine, and the results of this study provide reference data for using Chinese traditional medicine safely in clinic and developing Chinese traditional medicine. PMID:19385252

  12. Evaluation of humidity, cloud and precipitation predicted by fourteen MAP D-PHASE mesocale models

    NASA Astrophysics Data System (ADS)

    Polade, Suraj; Ament, Felix

    2010-05-01

    Precipitation is the final component of the atmospheric part of hydrological cycle. Consequently, all model errors in this complex process chain are accumulated in quantitative precipitation forecasts. Furthermore, many parts of forecasting system can cause errors: poor model formulations, inaccurate initial or boundary data, limited grid resolution etc. We will demonstrate how a multivariate verification of fourteen different mesoscale forecasting systems can be used to disentangle this multitude of effects and to identify specific model deficits. The models forecasts were collected in summer 2007 during the forecast demonstration experiment MAP D-PHASE in the Alpine region and comprise both results from convection permitting high-resolution models as well as systems with parameterized deep convection. The observational basis to evaluate these models is obtained from the remote-sensing observations gathered during general observation period (GOP) of the German research program on quantitative precipitation forecasts. Analyses of integrated water vapour (IWV) content, cloud cover and precipitation rate are performed for the summer 2007 over the southern Germany. By analyzing which type of models show similar error structures, it is possible to decide whether the resolution, the model formulation or the initial conditions have a dominant impact on the model error. Particular attention is paid to the representation of the diurnal cycle in all considered quantities. This reveals the great impact of introducing a dry bias by the assimilation of day time radiosondes: There is a significant loss of IWV, a reduction in low and high cloud cover, also sudden decrease of precipitation at 1200 UTC. Finally, we will discuss the added value of using high resolution convection permitting models and of implementing a rapid update cycle of model initialization.

  13. Expression of fourteen novel obesity-related genes in zucker diabetic fatty rats

    PubMed Central

    2012-01-01

    Background Genome-wide association studies (GWAS) are useful to reveal an association between single nucleotide polymorphisms and different measures of obesity. A multitude of new loci has recently been reported, but the exact function of most of the according genes is not known. The aim of our study was to start elucidating the function of some of these genes. Methods We performed an expression analysis of fourteen genes, namely BDNF, ETV5, FAIM2, FTO, GNPDA2, KCTD15, LYPLAL1, MCR4, MTCH2, NEGR1, NRXN3, TMEM18, SEC16B and TFAP2B, via real-time RT-PCR in adipose tissue of the kidney capsule, the mesenterium and subcutaneum as well as the hypothalamus of obese Zucker diabetic fatty (ZDF) and Zucker lean (ZL) rats at an age of 22 weeks. Results All of our target genes except for SEC16B showed the highest expression in the hypothalamus. This suggests a critical role of these obesity-related genes in the central regulation of energy balance. Interestingly, the expression pattern in the hypothalamus showed no differences between obese ZDF and lean ZL rats. However, LYPLAL1, TFAP2B, SEC16B and FAIM2 were significantly lower expressed in the kidney fat of ZDF than ZL rats. NEGR1 was even lower expressed in subcutaneous and mesenterial fat, while MTCH2 was higher expressed in the subcutaneous and mesenterial fat of ZDF rats. Conclusion The expression pattern of the investigated obesity genes implies for most of them a role in the central regulation of energy balance, but for some also a role in the adipose tissue itself. For the development of the ZDF phenotype peripheral rather than central mechanisms of the investigated genes seem to be relevant. PMID:22553958

  14. Harnessing Energy from the Sun for Six Billion People

    SciTech Connect

    Daniel Nocera

    2011-09-12

    Daniel Nocera, a Massachusetts Institute of Technology professor whose recent research focuses on solar-powered fuels, presents a Brookhaven Science Associates Distinguished Lecture, titled "Harnessing Energy from the Sun for Six Billion People -- One at a Time."

  15. NASA Now Minute: Earth and Space Science: 100 Billion Planets

    NASA Video Gallery

    Stephen Kane, co-author of the article, “Study Shows Our Galaxy has 100Billion Planets” reveals details about this incredible study explainsjust how common planets are in our Milky Way galaxy...

  16. Harnessing Energy from the Sun for Six Billion People

    ScienceCinema

    Daniel Nocera

    2013-07-19

    Daniel Nocera, a Massachusetts Institute of Technology professor whose recent research focuses on solar-powered fuels, presents a Brookhaven Science Associates Distinguished Lecture, titled "Harnessing Energy from the Sun for Six Billion People -- One at a Time."

  17. Academic Pork Barrel Tops $2-Billion for the First Time.

    ERIC Educational Resources Information Center

    Brainard, Jeffrey; Borrego, Anne Marie

    2003-01-01

    Describes how, despite the growing budget deficit, Congress directed a record $2 billion to college projects in 2003, many of them dealing with security and bioterrorism. Includes data tables on the earmarks. (EV)

  18. Multi-Billion Shot, High-Fluence Exposure of Cr(4+): YAG Passive Q-Switch

    NASA Technical Reports Server (NTRS)

    Stephen, Mark A.; Dallas, Joseph L.; Afzal, Robert S.

    1997-01-01

    NASA's Goddard Space Flight Center is developing the Geoscience Laser Altimeter System (GLAS) employing a diode pumped, Q-Switched, ND:YAG laser operating at 40 Hz repetition rate. To meet the five-year mission lifetime goal, a single transmitter would accumulate over 6.3 billion shots. Cr(4+):YAG is a promising candidate material for passively Q-switching the laser. Historically, the performance of saturable absorbers has degraded over long-duration usage. To measure the multi-billion shot performance of Cr(4+):YAG, a passively Q-switched GLAS-like oscillator was tested at an accelerated repetition rate of 500 Hz. The intracavity fluence was calculated to be approximately 2.5 J/cm(exp 2). The laser was monitored autonomously for 165 days. There was no evidence of change in the material optical properties during the 7.2 billion shot test.. All observed changes in laser operation could be attributed to pump laser diode aging. This is the first demonstration of multi-billion shot exposure testing of Cr(4+):YAG in this pulse energy regime

  19. Hydroelectric dams need billions for rehab

    SciTech Connect

    Carr, F.H.; Soast, A.

    1993-01-11

    Many of the Corps of Engineers older hydroelectric dams will require major rehabilitation over the next ten years. Preventive maintenance, repair work, and major rehabilitation of the Corp's hydro dams in inadequate because the revenue generated by sales of electricity, by law, is returned to the Treasury. Most multimillion dollar rehabilitation projects require specific approval for funding by Congress and securing it is a long and difficult process. It is hoped the funding problem will soon be addressed by the Clinton administration. Already, nearly one-sixth of the 2,154 Mw of hydro is unavailable because with hydro units are either out of service or operating at less than full capacity.

  20. Food and population: beyond five billion.

    PubMed

    Hendry, P

    1988-04-01

    The developing countries, with about 3/4 of the world's population, account for less than 1/2 of the production of major food crops. The Third World's per capita food production of 260 kilograms in 1983 was only 1/3 of that in the developed countries. Yet China and India, the most populous countries in the world, have cut fertility rates and moved to food self-sufficiency. An illustration of the food/population dynamic is that although production of food staples in North Africa and the Middle East is projected to expand at about the same rate as that of Asia, about 2.9% annually, owing to a much more rapid rate of population increase, they will achieve only a 0.2% increase in output per person per year, compared with a 1.4% annual growth rate in Asia. In the longer term, higher dietary levels per capita for a world population double that of the present would imply at least a tripling of demand for dietary staples. But more intensive cultivation would place natural resources, many already degraded, under much greater stress. Balancing population, food, and resources for sustained survival is a continual process. The principle cause of hunger and malnutrition is poverty; it is more determinative of nutritional status than aggregate food production. PMID:12341721

  1. Winglets Save Billions of Dollars in Fuel Costs

    NASA Technical Reports Server (NTRS)

    2010-01-01

    The upturned ends now featured on many airplane wings are saving airlines billions of dollars in fuel costs. Called winglets, the drag-reducing technology was advanced through the research of Langley Research Center engineer Richard Whitcomb and through flight tests conducted at Dryden Flight Research Center. Seattle-based Aviation Partners Boeing -- a partnership between Aviation Partners Inc., of Seattle, and The Boeing Company, of Chicago -- manufactures Blended Winglets, a unique design featured on Boeing aircraft around the world. These winglets have saved more than 2 billion gallons of jet fuel to date, representing a cost savings of more than $4 billion and a reduction of almost 21.5 million tons in carbon dioxide emissions.

  2. The BIA As Banker: "Trust" Is Hard When Billions Disappear.

    ERIC Educational Resources Information Center

    Johansen, Bruce E.

    1997-01-01

    The federal government's trust responsibility toward Native Americans involves protection of their lands, resources, and right to self-government and provision of services (including education). However, the Bureau of Indian Affairs has misplaced billions of dollars owed Native American individuals and tribes and now faces class-action litigation.…

  3. Bill and Melinda Gates Pledge $1-Billion for Minority Scholarships.

    ERIC Educational Resources Information Center

    Monaghan, Peter; Lederman, Douglas; van der Werf, Martin; Pulley, John

    1999-01-01

    Reports on a $1 billion dollar grant from Bill and Melinda Gates to send 20,000 low-income minority students to college. The Gates Millenium Scholars Program will require students to demonstrate financial need and maintain a 3.0 grade point average in college. A list of the largest private gifts to higher education since 1967 is also provided. (DB)

  4. Marine Gastrotricha of the Near East: 1. Fourteen new species of Macrodasyida and a redescription of Dactylopodola agadasys Hochberg, 2003.

    PubMed

    Hummon, William D

    2011-01-01

    The near eastern geographical region is almost devoid of reports of macrodasyidan gastrotrichs, the exceptions themselves being part of this study. Here, as Part 1 are described fourteen new Macrodasyida from countries of the Near East (Cyprus, Egypt and Israel, representing both the Mediterranean and the Red Seas), and a redescription of the previously described Dactylopodolidae: Dactylopodola agadasys Hochberg, 2002. The new species are: Cephalodasyidae (2) - Cephalodasys dolichosomus; Cephalodasys saegailus; Dactylopodolidae (1) Dendrodasys rubomarinus; Macrodasyidae (5) - Macrodasys imbricatus; Macrodasys macrurus; Macrodasys nigrocellus; Macrodasys scleracrus; Urodasys toxostylus; Thaumastodermatidae(4) - Tetranchyroderma corallium; Tetranchyroderma rhopalotum; Tetranchyroderma sinaiensis; Tetranchyroderma xenodactylum; Turbanellidae(2) - Paraturbanella levantia; Turbanella erythrothalassia - spp. n. PMID:21594074

  5. Marine Gastrotricha of the Near East: 1. Fourteen new species of Macrodasyida and a redescription of Dactylopodola agadasys Hochberg, 2003

    PubMed Central

    Hummon, William D.

    2011-01-01

    Abstract The near eastern geographical region is almost devoid of reports of macrodasyidan gastrotrichs, the exceptions themselves being part of this study. Here, as Part 1 are described fourteen new Macrodasyida from countries of the Near East (Cyprus, Egypt and Israel, representing both the Mediterranean and the Red Seas), and a redescription of the previously described Dactylopodolidae: Dactylopodola agadasys Hochberg, 2002. The new species are: Cephalodasyidae (2) - Cephalodasys dolichosomus; Cephalodasys saegailus; Dactylopodolidae (1) Dendrodasys rubomarinus; Macrodasyidae (5) - Macrodasys imbricatus; Macrodasys macrurus; Macrodasys nigrocellus; Macrodasys scleracrus; Urodasys toxostylus; Thaumastodermatidae(4) - Tetranchyroderma corallium; Tetranchyroderma rhopalotum; Tetranchyroderma sinaiensis; Tetranchyroderma xenodactylum; Turbanellidae(2) - Paraturbanella levantia; Turbanella erythrothalassia - spp. n. PMID:21594074

  6. Severe Obesity In Adults Cost State Medicaid Programs Nearly $8 Billion In 2013.

    PubMed

    Wang, Y Claire; Pamplin, John; Long, Michael W; Ward, Zachary J; Gortmaker, Steven L; Andreyeva, Tatiana

    2015-11-01

    Efforts to expand Medicaid while controlling spending must be informed by a deeper understanding of the extent to which the high medical costs associated with severe obesity (having a body mass index of [Formula: see text] or higher) determine spending at the state level. Our analysis of population-representative data indicates that in 2013, severe obesity cost the nation approximately $69 billion, which accounted for 60 percent of total obesity-related costs. Approximately 11 percent of the cost of severe obesity was paid for by Medicaid, 30 percent by Medicare and other federal health programs, 27 percent by private health plans, and 30 percent out of pocket. Overall, severe obesity cost state Medicaid programs almost $8 billion a year, ranging from $5 million in Wyoming to $1.3 billion in California. These costs are likely to increase following Medicaid expansion and enhanced coverage of weight loss therapies in the form of nutrition consultation, drug therapy, and bariatric surgery. Ensuring and expanding Medicaid-eligible populations' access to cost-effective treatment for severe obesity should be part of each state's strategy to mitigate rising obesity-related health care costs. PMID:26526251

  7. A 17-billion-solar-mass black hole in a group galaxy with a diffuse core.

    PubMed

    Thomas, Jens; Ma, Chung-Pei; McConnell, Nicholas J; Greene, Jenny E; Blakeslee, John P; Janish, Ryan

    2016-04-21

    Quasars are associated with and powered by the accretion of material onto massive black holes; the detection of highly luminous quasars with redshifts greater than z = 6 suggests that black holes of up to ten billion solar masses already existed 13 billion years ago. Two possible present-day 'dormant' descendants of this population of 'active' black holes have been found in the galaxies NGC 3842 and NGC 4889 at the centres of the Leo and Coma galaxy clusters, which together form the central region of the Great Wall--the largest local structure of galaxies. The most luminous quasars, however, are not confined to such high-density regions of the early Universe; yet dormant black holes of this high mass have not yet been found outside of modern-day rich clusters. Here we report observations of the stellar velocity distribution in the galaxy NGC 1600--a relatively isolated elliptical galaxy near the centre of a galaxy group at a distance of 64 megaparsecs from Earth. We use orbit superposition models to determine that the black hole at the centre of NGC 1600 has a mass of 17 billion solar masses. The spatial distribution of stars near the centre of NGC 1600 is rather diffuse. We find that the region of depleted stellar density in the cores of massive elliptical galaxies extends over the same radius as the gravitational sphere of influence of the central black holes, and interpret this as the dynamical imprint of the black holes. PMID:27049949

  8. Identification of a Testis-Enriched Heat Shock Protein and Fourteen Members of Hsp70 Family in the Swamp Eel

    PubMed Central

    He, Yan; Luo, Majing; Yi, Minhan; Sheng, Yue; Cheng, Yibin; Zhou, Rongjia; Cheng, Hanhua

    2013-01-01

    Background Gonad differentiation is one of the most important developmental events in vertebrates. Some heat shock proteins are associated with gonad development. Heat shock protein 70 (Hsp70) in the teleost fish and its roles in sex differentiation are poorly understood. Methods and Findings We have identified a testis-enriched heat shock protein Hspa8b2 in the swamp eel using Western blot analysis and Mass Spectrometry (MS). Fourteen Hsp70 family genes were further identified in this species based on transcriptome information. The phylogenetic tree of Hsp70 family was constructed using the Maximum Likelihood method and their expression patterns in the swamp eel gonads were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Conclusion There are fourteen gene members in the Hsp70 family in the swamp eel genome. Hsp70 family, particularly Hspa8, has expanded in the species. One of the family members Hspa8b2 is predominantly expressed in testis of the swamp eel. PMID:23750249

  9. BLINK: Billion Lines INdexing in a clicK

    NASA Astrophysics Data System (ADS)

    Kamennoff, N.; Foucaud, S.; Reybier, S.; Tsai, M.-F.; Tang, C.-H.

    2012-09-01

    The coming generation of sky surveys are going to provide measurements for properties of a number of objects like never have been reached before. Astronomical databases will have to deal with requests on several billions of entries at once, and therefore a new computational framework is vital for the next generation of Data-Centers. As part of the efforts linked to the setting up of the Taiwan Extragalactic Astronomical Data Center (TWEA-DC), Billion Lines INdexing in a clicK (BLINK) is developed to satisfy this role. BLINK is a framework that aims to ease access to large amount of data and share analysis software amongst users. BLINK is also designed to be parallelized and distributed on large amount of heterogeneous resources. BLINK will propose at first a very fast indexing algorithm and cross-matching capability, enabling to gather multiwavelength information of large chunk of the sky in a very limited period of time.

  10. Synthetic, Spectroscopic and Biocidal Aspects of Heterobimetallic Complexes Comprising Platinum(II) and a Group Four or Fourteen Element

    PubMed Central

    Sharma, Kripa

    2000-01-01

    Heterobimetallic complexes with varying amines have been synthesized by the reaction of [Pt(C2H8N2)2]Cl2 with group four or fourteen organometallic dichlorides, viz., R2MCl2 and Cp2M'Cl2 in a 1:2 molar ratio in MeOH (where M=Si or Sn, M'= Ti or Zr and R=Ph or Me). These complexes have been characterized by elemental analysis, molecular weight determinations, magnetic measurements, conductance, IR, 1H NMR and electronic spectra. The spectral data suggest a square planar geometry for all the complexes. Conductivity data suggest that they behave as electrolytes. These monometallic precursors along with their complexes have been screened in vitro against a number of pathogenic fungi and bacteria to assess their growth inhibiting potential. PMID:18475917

  11. Fourteen new species, one new genus, and eleven new country or state records for New World Lamiinae (Coleoptera, Cerambycidae).

    PubMed

    Martins, Ubirajara R; Santos-Silva, Antonio; Galileo, Maria Helena M

    2015-01-01

    Fourteen new species and one new genus are described from the New World in Lamiinae (Coleoptera: Cerambycidae): Bisaltes (Bisaltes) lingafelteri sp. nov., Trestonia skelleyi sp. nov. and Psapharochrus langeri sp. nov. from Bolivia; Eupogonius azteca sp. nov., Aegomorphus mexicanus sp. nov., Lamacoscylus albatus sp. nov., Lamacoscylus obscurus sp. nov. and Piruanycha wappesi sp. nov. from Mexico; Dolichestola egeri sp. nov. and Wappesellus cavus gen. nov., sp. nov. from Brazil (Rondônia); Scleronotus virgatus sp. nov. from Venezuela; Oreodera casariae sp. nov. from Panama; Alampyris bicolor sp. nov. from Costa Rica; and Emphytoeciosoma flava sp. nov. from Peru. Additionally, eleven new country/state records are established in Lamiinae: three for Peru; three for Bolivia; one for Mexico; one for Uruguay; and two for Brazil (Rondônia) (state records). Bisaltes (Bisaltes) lingafelteri, Eupogonius azteca, Aegomorphus mexicanus, Lamacoscylus albatus, Lamacoscylus obscurus, Piruanycha wappesi, Scleronotus virgatus, Alampyris bicolor, Emphytoeciosoma flava and Wappesellus are included in new or known keys. PMID:26249940

  12. [Analysis of fourteen French national programmes on physical activity and sports as determinants of health from 2001 to 2006].

    PubMed

    Bréchat, Pierre-Henri; Vogel, Thomas; Berthel, Marc; Kaltenbach, Georges; Le Divenah, Aude; Segouin, Christophe; Rymer, Roland; Lonsdorfer, Jean

    2009-01-01

    Physical activity and sports are considered as one of the determinants of health. The aim of this study is to review the rationale for the formulation of this public health issue and its integration in national action plans. The study shows that fourteen national programmes were drafted and implemented between 2001 and 2006 by seven institutions. The research methodology was based on crossing data obtained from semi-directed interviews and documents regarding the design, implementation and follow-up of these programmes. For the conditions of the success, the fourteen actions scored an average of 175.0 +/- 66.9 out of 300%. Public health actors and professionals must be given more opportunities to involve themselves and engage in developing stronger relationships and linkages, in particular with the institutional and community settings. In general, the most invested parts of a programme are the structural and operational aspects of activities. Six significant points surfaced from the study: consideration of drug use as an addictive behaviour; recognition of the psychological stress of professional athletes; acknowledgment of youth as being at high risk for doping behaviour; integration of the concept that physical activity and sports must take the benefit/risk perspective into account; and the necessity to promote health. Through the exchange of numerous local and regional experiences, an optimisation of their synergistic connections was made possible on a continuum extending from "health promotion through physical activity and sports" to "prevention of drug-use and doping behaviours". Professionals have been able to develop actions in the above-mentioned domains across this continuum that have, to date, remained isolated. Proposals are made to strengthen these dynamics. Other health determinants and public health priorities could be investigated with the same methodology. PMID:19425524

  13. Billion particle linac simulations for future light sources

    SciTech Connect

    Ryne, R. D.; Venturini, M.; Zholents, A. A.; Qiang, J.

    2008-09-25

    In this paper we report on multi-physics, multi-billion macroparticle simulation of beam transport in a free electron laser (FEL) linac for future light source applications. The simulation includes a self-consistent calculation of 3D space-charge effects, short-range geometry wakefields, longitudinal coherent synchrotron radiation (CSR) wakefields, and detailed modeling of RF acceleration and focusing. We discuss the need for and the challenges associated with such large-scale simulation. Applications to the study of the microbunching instability in an FEL linac are also presented.

  14. Fourteen Writing Strategies

    ERIC Educational Resources Information Center

    Turner, Thomas; Broemmel, Amy

    2006-01-01

    Any science teacher who wants his or her students to be engaged in real science is going to engage them in real science writing. Writing in science should begin with clear, imaginative writing purposes and stimuli that are then scaffolded in such a way that students are able to find an organizational structure for their writing. Writing fluency is…

  15. A 17-billion-solar-mass black hole in a group galaxy with a diffuse core

    NASA Astrophysics Data System (ADS)

    Thomas, Jens; Ma, Chung-Pei; McConnell, Nicholas J.; Greene, Jenny E.; Blakeslee, John P.; Janish, Ryan

    2016-04-01

    Quasars are associated with and powered by the accretion of material onto massive black holes; the detection of highly luminous quasars with redshifts greater than z = 6 suggests that black holes of up to ten billion solar masses already existed 13 billion years ago. Two possible present-day ‘dormant’ descendants of this population of ‘active’ black holes have been found in the galaxies NGC 3842 and NGC 4889 at the centres of the Leo and Coma galaxy clusters, which together form the central region of the Great Wall—the largest local structure of galaxies. The most luminous quasars, however, are not confined to such high-density regions of the early Universe; yet dormant black holes of this high mass have not yet been found outside of modern-day rich clusters. Here we report observations of the stellar velocity distribution in the galaxy NGC 1600—a relatively isolated elliptical galaxy near the centre of a galaxy group at a distance of 64 megaparsecs from Earth. We use orbit superposition models to determine that the black hole at the centre of NGC 1600 has a mass of 17 billion solar masses. The spatial distribution of stars near the centre of NGC 1600 is rather diffuse. We find that the region of depleted stellar density in the cores of massive elliptical galaxies extends over the same radius as the gravitational sphere of influence of the central black holes, and interpret this as the dynamical imprint of the black holes.

  16. Scalable in-memory RDFS closure on billions of triples.

    SciTech Connect

    Goodman, Eric L.; Mizell, David

    2010-06-01

    We present an RDFS closure algorithm, specifically designed and implemented on the Cray XMT supercomputer, that obtains inference rates of 13 million inferences per second on the largest system configuration we used. The Cray XMT, with its large global memory (4TB for our experiments), permits the construction of a conceptually straightforward algorithm, fundamentally a series of operations on a shared hash table. Each thread is given a partition of triple data to process, a dedicated copy of the ontology to apply to the data, and a reference to the hash table into which it inserts inferred triples. The global nature of the hash table allows the algorithm to avoid a common obstacle for distributed memory machines: the creation of duplicate triples. On LUBM data sets ranging between 1.3 billion and 5.3 billion triples, we obtain nearly linear speedup except for two portions: file I/O, which can be ameliorated with the additional service nodes, and data structure initialization, which requires nearly constant time for runs involving 32 processors or more.

  17. Polymorphisms in Epigenetic and Meat Quality Related Genes in Fourteen Cattle Breeds and Association with Beef Quality and Carcass Traits

    PubMed Central

    Liu, Xuan; Usman, Tahir; Wang, Yachun; Wang, Zezhao; Xu, Xianzhou; Wu, Meng; Zhang, Yi; Zhang, Xu; Li, Qiang; Liu, Lin; Shi, Wanhai; Qin, Chunhua; Geng, Fanjun; Wang, Congyong; Tan, Rui; Huang, Xixia; Liu, Airong; Wu, Hongjun; Tan, Shixin; Yu, Ying

    2015-01-01

    Improvement for carcass traits related to beef quality is the key concern in beef production. Recent reports found that epigenetics mediates the interaction of individuals with environment and nutrition. The present study was designed to analyze the genetic effect of single nucleotide polymorphisms (SNPs) in seven epigenetic-related genes (DNMT1, DNMT3a, DNMT3b, DNMT3L, Ago1, Ago2, and HDAC5) and two meat quality candidate genes (CAPN1 and PRKAG3) on fourteen carcass traits related to beef quality in a Snow Dragon beef population, and also to identify SNPs in a total of fourteen cattle populations. Sixteen SNPs were identified and genotyped in 383 individuals sampled from the 14 cattle breeds, which included 147 samples from the Snow Dragon beef population. Data analysis showed significant association of 8 SNPs within 4 genes related to carcass and/or meat quality traits in the beef populations. SNP1 (13154420A>G) in exon 17 of DNMT1 was significantly associated with rib-eye width and lean meat color score (p<0.05). A novel SNP (SNP4, 76198537A>G) of DNMT3a was significantly associated with six beef quality traits. Those individuals with the wild-type genotype AA of DNMT3a showed an increase in carcass weight, chilled carcass weight, flank thicknesses, chuck short rib thickness, chuck short rib score and in chuck flap weight in contrast to the GG genotype. Five out of six SNPs in DNMT3b gene were significantly associated with three beef quality traits. SNP15 (45219258C>T) in CAPN1 was significantly associated with chuck short rib thickness and lean meat color score (p<0.05). The significant effect of SNP15 on lean meat color score individually and in combination with each of other 14 SNPs qualify this SNP to be used as potential marker for improving the trait. In addition, the frequencies of most wild-type alleles were higher than those of the mutant alleles in the native and foreign cattle breeds. Seven SNPs were identified in the epigenetic-related genes. The SNP

  18. Federal Library Committee Annual Report, Fiscal Year 1971.

    ERIC Educational Resources Information Center

    Cylke, Frank Kurt

    The efforts of the Secretarial Work Groups during fiscal year 1971 are described. Three research projects were funded and one is pending. Fourteen publications were issued by, for, or in cooperation with the Federal Library Committee. (AB)

  19. The continuing cost of privatization: extra payments to Medicare Advantage plans jump to $11.4 billion in 2009.

    PubMed

    Biles, Brian; Pozen, Jonah; Guterman, Stuart

    2009-05-01

    The Medicare Modernization Act of 2003 explicitly increased Medicare payments to private Medicare Advantage (MA) plans. As a result, MA plans have, for the past six years, been paid more for their enrollees than they would be expected to cost in traditional fee-for-service Medicare. Payments to MA plans in 2009 are projected to be 13 percent greater than the corresponding costs in traditional Medicare--an average of $1,138 per MA plan enrollee, for a total of $11.4 billion. Although the extra payments are used to provide enrollees additional benefits, those benefits are not available to all beneficiaries-- but they are financed by general program funds. If payments to MA plans were instead equal to the spending level under traditional Medicare, the more than $150 billion in savings over 10 years could be used to finance improved benefits for the low-income elderly and disabled, or for expanding health-insurance coverage. PMID:19449498

  20. $75 Billion in Formula Grants Failed to Drive Reform. Can $5 Billion in Competitive Grants Do the Job? Education Stimulus Watch. Special Report 2

    ERIC Educational Resources Information Center

    Smarick, Andy

    2009-01-01

    In early 2009, Congress passed and President Barack Obama signed into law the American Recovery and Reinvestment Act (ARRA), the federal government's nearly $800 billion stimulus legislation. According to key members of Congress and the Obama administration, the education portions of the law, totaling about $100 billion, were designed both to…

  1. Anti-bacterial activity and brine shrimp lethality bioassay of methanolic extracts of fourteen different edible vegetables from Bangladesh

    PubMed Central

    Ullah, M. Obayed; Haque, Mahmuda; Urmi, Kaniz Fatima; Zulfiker, Abu Hasanat Md.; Anita, Elichea Synthi; Begum, Momtaj; Hamid, Kaiser

    2013-01-01

    Objective To investigate the antibacterial and cytotoxic activity of fourteen different edible vegetables methanolic extract from Bangladesh. Methods The antibacterial activity was evaluated using disc diffusion assay method against 12 bacteria (both gram positive and gram negative). The plant extracts were also screened for cytotoxic activity using the brine shrimp lethality bioassay method and the lethal concentrations (LC50) were determined at 95% confidence intervals by analyzing the data on a computer loaded with “Finney Programme”. Results All the vegetable extracts showed low to elevated levels of antibacterial activity against most of the tested strains (zone of inhibition=5-28 mm). The most active extract against all bacterial strains was from Xanthium indicum which showed remarkable antibacterial activity having the diameter of growth inhibition zone ranging from 12 to 28 mm followed by Alternanthera sessilis (zone of inhibition=6-21 mm). All extracts exhibited considerable general toxicity towards brine shrimps. The LC50 value of the tested extracts was within the range of 8.447 to 60.323 µg/mL with respect to the positive control (vincristine sulphate) which was 0.91 µg/mL. Among all studied extracts, Xanthium indicum displayed the highest cytotoxic effect with LC50 value of 8.447 µg/mL. Conclusions The results of the present investigation suggest that most of the studied plants are potentially good source of antibacterial and anticancer agents. PMID:23570009

  2. Parametrization and Classification of 20 Billion LSST Objects: Lessons from SDSS

    SciTech Connect

    Ivezic, Z.; Axelrod, T.; Becker, A.C.; Becla, J.; Borne, K.; Burke, David L.; Claver, C.F.; Cook, K.H.; Connolly, A.; Gilmore, D.K.; Jones, R.L.; Juric, M.; Kahn, Steven M.; Lim, K-T.; Lupton, R.H.; Monet, D.G.; Pinto, P.A.; Sesar, B.; Stubbs, Christopher W.; Tyson, J.Anthony; /UC, Davis

    2011-11-10

    The Large Synoptic Survey Telescope (LSST) will be a large, wide-field ground-based system designed to obtain, starting in 2015, multiple images of the sky that is visible from Cerro Pachon in Northern Chile. About 90% of the observing time will be devoted to a deep-wide-fast survey mode which will observe a 20,000 deg{sup 2} region about 1000 times during the anticipated 10 years of operations (distributed over six bands, ugrizy). Each 30-second long visit will deliver 5{sigma} depth for point sources of r {approx} 24.5 on average. The co-added map will be about 3 magnitudes deeper, and will include 10 billion galaxies and a similar number of stars. We discuss various measurements that will be automatically performed for these 20 billion sources, and how they can be used for classification and determination of source physical and other properties. We provide a few classification examples based on SDSS data, such as color classification of stars, color-spatial proximity search for wide-angle binary stars, orbital-color classification of asteroid families, and the recognition of main Galaxy components based on the distribution of stars in the position-metallicity-kinematics space. Guided by these examples, we anticipate that two grand classification challenges for LSST will be (1) rapid and robust classification of sources detected in difference images, and (2) simultaneous treatment of diverse astrometric and photometric time series measurements for an unprecedentedly large number of objects.

  3. As its R D budget nears $2 billion Bayer rethinks priorities

    SciTech Connect

    Rotman, D.

    1993-03-17

    With a planned 1993 research and development budget of roughly DM3.2 billion ($1.95 billion), Bayer (Leverkusen) is the industry's biggest R D spender. But while the German giant lays out a healthy 7% of sales on R D, caution is clearly replacing the heady spending spurts of several years ago. And faced with an increasingly rigorous corporate business restructuring, Bayer - like others in the chemical industry - is rethinking its R D strategies. While Bayer's R D stress is clearly on life sciences, the company remains bullish on certain new materials, particularly inorganics. It has developed several engineering ceramics for use in automotive engines, with the most advanced - a silicon nitride - being road tested in Mercedes models. [open quotes]We have the materials and know their properties,[close quotes] says Hauke Fuerstenwerth, Bayer's head of R D coordination. The challenge now, he says, is to demonstrate a commercially attractive process for large-scale production. Bayer is also pursuing new silicon wafer technology. Already in small-scale production, the firm is testing an amorphous silicon that is intended to be far cheaper than existing crystalline silicon wafers, while maintaining suitable properties for applications such as solar collectors.

  4. Bigger, Better Catalog Unveils Half a Billion Celestial Objects

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These frames are samples from the photographic sky surveys, which have been digitized by a technical team at the Space Telescope Science Institute to support the Hubble Space Telescope operations. The team processed these images to create a new astronomical catalog, called the Guide Star Catalog II. This project was undertaken by the Space Telescope Science Institute as an upgrade to an earlier sky survey and catalog (DSS-I and GSC-I), initially done to provide guide stars for pointing the Hubble Space Telescope. By virtue of its sheer size, the DSS-II and GSC-II have many research applications for both professional and amateur astronomers. [Top] An example from the DSS-II shows the Rosette Nebula, (originally photographed by the Palomar Observatory) as digitized in the DSS-I (left) and DSS-II (right). The DSS-II includes views of the sky at both red and blue wavelengths, providing invaluable color information on about one billion deep-sky objects. [Bottom] This blow-up of the inset box in the raw DSS-I scan shows examples of the GSC-I and the improved GSC-II catalogs. Astronomers extracted the stars from the scanned plate of the Rosette and listed them in the catalogs. The new GSC-II catalog provides the colors, positions, and luminosities of nearly half a billion stars -- over 20 times as many as the original GSC-I. The GSC-II contains information on stars as dim as the 19th magnitude. Credit: NASA, the DSS-II and GSC-II Consortia (with images from the Palomar Observatory-STScI Digital Sky Survey of the northern sky, based on scans of the Second Palomar Sky Survey are copyright c 1993-1999 by the California Institute of Technology)

  5. Fatty acid composition of fourteen seashore mallow (Kosteletzkya pentacarpos) seed oil accessions collected from the Atlantic and Gulf coasts of the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seashore mallow (Kosteletzkya pentacarpos) is a flowering perennial halophytic herb belonging to the family Malvaceae that is found in marshes along the Atlantic and Gulf coasts of the United States. Fourteen accessions were collected from wild populations along the Atlantic (n = 8) and Gulf (n = 6)...

  6. A Powerful Toolkit for Synthetic Biology: Over 3.8 Billion Years of Evolution

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.

    2010-01-01

    The combination of evolutionary with engineering principles will enhance synthetic biology. Conversely, synthetic biology has the potential to enrich evolutionary biology by explaining why some adaptive space is empty, on Earth or elsewhere. Synthetic biology, the design and construction of artificial biological systems, substitutes bio-engineering for evolution, which is seen as an obstacle. But because evolution has produced the complexity and diversity of life, it provides a proven toolkit of genetic materials and principles available to synthetic biology. Evolution operates on the population level, with the populations composed of unique individuals that are historical entities. The source of genetic novelty includes mutation, gene regulation, sex, symbiosis, and interspecies gene transfer. At a phenotypic level, variation derives from regulatory control, replication and diversification of components, compartmentalization, sexual selection and speciation, among others. Variation is limited by physical constraints such as diffusion, and chemical constraints such as reaction rates and membrane fluidity. While some of these tools of evolution are currently in use in synthetic biology, all ought to be examined for utility. A hybrid approach of synthetic biology coupled with fine-tuning through evolution is suggested

  7. 3.5 billion years of glass bioalteration: Volcanic rocks as a basis for microbial life?

    NASA Astrophysics Data System (ADS)

    Staudigel, Hubert; Furnes, Harald; McLoughlin, Nicola; Banerjee, Neil R.; Connell, Laurie B.; Templeton, Alexis

    2008-08-01

    Alteration textures in volcanic glass from the seafloor fall into two classes, one suggestive of abiotic/diffusive hydration and chemical exchange, and another likely to be caused by microbial, cavity-forming, congruent dissolution. Glass bioalteration is common in submarine lavas throughout the world's ocean, dominant in the upper 300 m of the oceanic crust, and found in all well-preserved ophiolites and greenstone belts dating back to 3.5 Ga. It may yield a significant fraction of the global biomass and geochemical fluxes and is relevant to the development of the earliest life on Earth. We present a critical review concerning these glass bioalteration textures and present new data on their microchemical environment. We explore arguments for their biogenicity and further develop the prevalent model for their formation by relating corrosion morphology to the mechanism of microbial dissolution. Biological alteration produces conspicuous micron-scale granular and tubular textures. Granular glass alteration is well explained by colonizing microbes that selectively dissolve the glass in their contact area, forming a sponge-like interconnected network of micron-sized cavities along glass surfaces. Tubular alteration meanwhile, is more likely to be caused by filamentous cell extensions in a process similar to fungal tunneling of soil feldspars and marine carbonates. While we see clear functional similarities to fungal dissolution behavior, we do not know whether fungal or prokaryotic organisms are involved. However, this functional constraint may eventually help to identify potential microbes responsible for these features, potentially including eukaryotic or prokaryotic organisms. Yet, we caution that these organisms may be difficult to identify and to study, because they are likely to be sparsely distributed, slow growing, and difficult to cultivate.

  8. The First Billion Years project: proto-galaxies reionizing the Universe

    NASA Astrophysics Data System (ADS)

    Paardekooper, Jan-Pieter; Khochfar, Sadegh; Dalla Vecchia, Claudio

    2013-02-01

    The contribution of stars in galaxies to cosmic reionization depends on the star formation history in the Universe, the abundance of galaxies during reionization, the escape fraction of ionizing photons and the clumping factor of the intergalactic medium. We compute the star formation rate and clumping factor during reionization in a cosmological volume using a high-resolution hydrodynamical simulation. We post-process the output with detailed radiative transfer simulations to compute the escape fraction of ionizing photons. Together, this gives us the opportunity to assess the contribution of galaxies to reionization self-consistently. The strong mass and redshift dependence of the escape fraction indicates that reionization occurred between z = 15 and 10 and was mainly driven by proto-galaxies forming in dark matter haloes with masses between 107 and 108 M⊙. More massive galaxies that are rare at these redshifts and have significantly lower escape fractions contribute less photons to the reionization process than the more-abundant low-mass galaxies. Star formation in the low-mass haloes is suppressed by radiative feedback from reionization, therefore these proto-galaxies only contribute when the part of the Universe they live in is still neutral. After z ˜ 10, massive galaxies become more abundant and provide most of the ionizing photons. In addition, we find that Population III stars are too short-lived and not frequent enough to have a major contribution to reionization. Although the stellar component of the proto-galaxies that produce the bulk of ionizing photons during reionization is too faint to be detected by the James Webb Space Telescope (JWST), these sources are brightest in the Hα and Lyα recombination lines, which will likely be detected by JWST in deep surveys.

  9. The violent youth of bright and massive cluster galaxies and their maturation over 7 billion years

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Lemaux, B. C.; Lubin, L. M.; Gal, R. R.; Kocevski, D. D.; Rumbaugh, N.; Squires, G.

    2014-07-01

    In this study, we investigate the formation and evolution mechanisms of the brightest cluster galaxies (BCGs) over cosmic time. At high redshift (z ˜ 0.9), we selected BCGs and most massive cluster galaxies (MMCGs) from the Cl1604 supercluster and compared them to low-redshift (z ˜ 0.1) counterparts drawn from the MCXC meta-catalogue, supplemented by Sloan Digital Sky Survey imaging and spectroscopy. We observed striking differences in the morphological, colour, spectral, and stellar mass properties of the BCGs/MMCGs in the two samples. High-redshift BCGs/MMCGs were, in many cases, star-forming, late-type galaxies, with blue broad-band colours, properties largely absent amongst the low-redshift BCGs/MMCGs. The stellar mass of BCGs was found to increase by an average factor of 2.51 ± 0.71 from z ˜ 0.9 to z ˜ 0.1. Through this and other comparisons, we conclude that a combination of major merging (mainly wet or mixed) and in situ star formation are the main mechanisms which build stellar mass in BCGs/MMCGs. The stellar mass growth of the BCGs/MMCGs also appears to grow in lockstep with both the stellar baryonic and total mass of the cluster. Additionally, BCGs/MMCGs were found to grow in size, on average, a factor of ˜3, while their average Sérsic index increased by ˜0.45 from z ˜ 0.9 to z ˜ 0.1, also supporting a scenario involving major merging, though some adiabatic expansion is required. These observational results are compared to both models and simulations to further explore the implications on processes which shape and evolve BCGs/MMCGs over the past ˜7 Gyr.

  10. The Violent Youth of Bright and Massive Cluster Galaxies and their Maturation over 7 Billion Years

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Lemaux, B.; Lubin, L. M.; Gal, R. R.; Kocevski, D. D.; Rumbaugh, N.; Squires, G.

    2014-12-01

    In this talk, I will present recent research on the formation and evolution mechanisms of the brightest cluster galaxies (BCGs) over cosmic time. At high redshift (z˜0.9) we selected BCGs and most massive cluster galaxies (MMCGs) from the Cl1604 supercluster and compared to low-redshift (z˜0.1) counterparts drawn from the MCXC meta-catalog and supplemented by SDSS imaging and spectroscopy. We observed striking differences in the morphological, color, spectral, and stellar mass properties of the BCGs/MMCGs in the two samples. High-redshift BCGs/MMCGs were, in many cases, star-forming, late-type galaxies, with blue broadband colors, properties largely absent amongst the low-redshift BCGs/MMCGs. The stellar mass of BCGs was found to increase by an average factor of 2.51±0.71 from z˜0.9 to z˜0.1. Through this and other comparisons we conclude that a combination of major merging (mainly wet or mixed) and in situ star formation are the main mechanisms which build stellar mass in BCGs/MMCGs. The stellar mass growth of the BCGs/MMCGs also appears to grow in lockstep with both the stellar baryonic and total mass of the cluster. Additionally, BCGs/MMCGs were found to grow in size, on average, a factor of ˜3 while their average Sérsic index increased by ˜0.45 from z˜0.9 to z˜0.1, also supporting a scenario involving major merging, though some adiabatic expansion is required. These observational results are compared to both models and simulations to further explore the implications on processes which shape and evolve BCGs/MMCGs over the past ˜7 Gyr.

  11. Three billion years of crustal evolution in eastern Canada: Constraints from receiver functions

    NASA Astrophysics Data System (ADS)

    Petrescu, L.; Bastow, I. D.; Darbyshire, F. A.; Gilligan, A.; Bodin, T.; Menke, W.; Levin, V.

    2016-02-01

    The geological record of SE Canada spans more than 2.5 Ga, making it a natural laboratory for the study of crustal formation and evolution over time. We estimate the crustal thickness, Poisson's ratio, a proxy for bulk crustal composition, and shear velocity (Vs) structure from receiver functions at a network of seismograph stations recently deployed across the Archean Superior Craton, the Proterozoic Grenville, and the Phanerozoic Appalachian provinces. The bulk seismic crustal properties and shear velocity structure reveal a correlation with tectonic provinces of different ages: the post-Archean crust becomes thicker, faster, more heterogeneous, and more compositionally evolved. This secular variation pattern is consistent with a growing consensus that crustal growth efficiency increased at the end of the Archean. A lack of correlation among elevation, Moho topography, and gravity anomalies within the Proterozoic belt is better explained by buoyant mantle support rather than by compositional variations driven by lower crustal metamorphic reactions. A ubiquitous ˜20 km thick high-Vs lower crustal layer is imaged beneath the Proterozoic belt. The strong discontinuity at 20 km may represent the signature of extensional collapse of an orogenic plateau, accommodated by lateral crustal flow. Wide anorthosite massifs inferred to fractionate from a mafic mantle source are abundant in Proterozoic geology and are underlain by high-Vs lower crust and a gradational Moho. Mafic underplating may have provided a source for these intrusions and could have been an important post-Archean process stimulating mafic crustal growth in a vertical sense.

  12. Black Hole Growth and Host Galaxy Co-Evolution Over 8 Billion Years of Cosmic Time

    NASA Astrophysics Data System (ADS)

    Simmons, Brooke D.

    Although much progress has been made in the investigation of the co-evolution of black holes and galaxies, the nature of AGN accretion triggers and AGN-host feedback remain open questions. Using samples of hard X-ray selected, moderate-luminosity AGN and their host galaxies from 0.25 < z < 2.67 in the GOODS deep multi-wavelength survey fields, this thesis assesses the growth rates and histories of these black holes, and uses their host galaxy morphologies and colors to test the applicability of established quasar-triggering models to lower-powered AGN. The analysis includes simulations of over 50,000 AGN+host galaxy images to assess the reliability of AGN-host decomposition, as well as a new technique to separate the spectral energy distribution of an obscured AGN from its dominant host galaxy. Moderate-luminosity AGN span a range of growth rates but are typically in a phase of slow growth (with ≈ 80% of the sample growing at less than 10% of the Eddington limit) with relatively high black hole masses (≈ 75% of the sample has MBH > 5 × 107 M⊙ , implying that they must have been growing at higher rates in the past in order to grow to the masses we observe. Additionally, a significant fraction of the host galaxies of moderate-luminosity AGN are disk-dominated: at the highest redshifts of the sample more than half of the host galaxies have at least 80% of their optical light from a disk. A further one-quarter to one-third of the sample (depending on redshift) has a significant disk contribution, with a stronger, but likely not dominant, bulge. Because major mergers both form bulges and destroy disks, this result indicates that models requiring major mergers to trigger the growth of black holes do not describe the majority of AGN. The range of both black hole growth rates and host galaxy colors and morphologies in the sample imply that secular processes are important to the growth of moderate-luminosity AGN, which collectively comprise a substantial fraction of the overall black hole growth in the universe.

  13. 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…

  14. Connecting galaxy and supermassive black hole growth during the last 8 billion years

    NASA Astrophysics Data System (ADS)

    Juneau, Stephanie

    It has become increasingly clear that a complete picture of galaxy evolution requires a better understanding of the role of Active Galactic Nuclei (AGN). In particular, they could be responsible for regulating star formation and galaxy growth via feedback processes. There are also competing views about the main modes of stellar growth and supermassive black hole growth in galaxies that need to be resolved. With high infrared luminosities (thus star formation rates) and a frequent occurrence of AGN, galaxies selected in the far-infrared wavebands form an ideal sample to search for a connection between AGN and star formation. The first part of this thesis contains a detailed analysis of the molecular gas properties of nearby infrared luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs). We find that the enhanced molecular gas density in the most IR-luminous systems can be explained by major galaxy mergers, and that AGN are more likely to reside in higher-density systems. While the frequent concurrence of AGN and galaxy mergers in ULIRGs was already established, this work provides a coherent framework that explains trends observed with five molecular gas tracers with a broad range of critical densities, and a comparison with simulations that reproduce observed molecular line ratios without invoking AGN-induced chemistry. The second part of the thesis presents an analysis of the AGN content of intermediate redshift galaxies (0.3 < z < 1). However, identifying complete AGN samples at these redshift is challenging because it is difficult to find X-ray weak or absorbed AGN. To alleviate this problem, we developed the Mass-Excitation (MEx) diagram, which is applicable out to redshift of ˜ 1 with existing optical spectra. It improves the overall AGN census by detecting AGN that are missed in even the most sensitive X-ray surveys. The new diagnostic was used to study the concurrence of star formation and AGN in 70 micron-selected galaxies from the Far-Infrared Deep Extragalactic Legacy survey. When multiple AGN diagnostics are combined, we find not only a high AGN fraction in FIR-selected galaxies (as high as for nearby FIR-selected galaxies), but a high incidence of X-ray absorbed AGN. These findings may have considerable implications for current views about the main mode of AGN growth.

  15. Atmospheric carbon dioxide concentrations before 2.2 billion years ago

    NASA Technical Reports Server (NTRS)

    Rye, R.; Kuo, P. H.; Holland, H. D.

    1995-01-01

    The composition of the Earth's early atmosphere is a subject of continuing debate. In particular, it has been suggested that elevated concentrations of atmospheric carbon dioxide would have been necessary to maintain normal surface temperatures in the face of lower solar luminosity in early Earth history. Fossil weathering profiles, known as palaeosols, have provided semi-quantitative constraints on atmospheric oxygen partial pressure (pO2) before 2.2 Gyr ago. Here we use the same well studied palaeosols to constrain atmospheric pCO2 between 2.75 and 2.2 Gyr ago. The observation that iron lost from the tops of these profiles was reprecipitated lower down as iron silicate minerals, rather than as iron carbonate, indicates that atmospheric pCO2 must have been less than 10(-1.4) atm--about 100 times today's level of 360 p.p.m., and at least five times lower than that required in one-dimensional climate models to compensate for lower solar luminosity at 2.75 Gyr. Our results suggest that either the Earth's early climate was much more sensitive to increases in pCO2 than has been thought, or that one or more greenhouse gases other than CO2 contributed significantly to the atmosphere's radiative balance during the late Archaean and early Proterozoic eons.

  16. The Universe as Viewed from Star Forming Galaxies over the Past Ten Billion Years

    NASA Astrophysics Data System (ADS)

    Ly, Chun; Malkan, M.; Lee, J. C.; Kashikawa, N.; Hayashi, M.; Motohara, K.; Subaru Deep Field Collaboration; NEWFIRM Narrow-band H-alpha Survey Team

    2010-01-01

    In this dissertation talk, I will discuss my work to provide improved constraints on the star formation history of the universe by (1) using narrow-band filters to identify galaxies to z 2.2 and (2) extending the Lyman break technique to z=1.5-3. These techniques efficiently isolate a large population of star-forming galaxies and enable measurement of the star formation rate via emission line and ultraviolet indicators. With the SDF team, we have conducted a narrow-band optical survey which yields a sample of 5000 galaxies within 0.25 square degree to z 1.5 detected by H-alpha, [OIII], or [OII]. Diagnostics based on broad-band optical colors are developed to resolve ambiguities in emission-line identification. In addition, with the NEWFIRM H-alpha team, we are working to extend optical studies into the near-infrared with NEWFIRM. We target H-alpha emitting galaxies at z 0.8 and z 2.2, which probes a critical period in the history of the universe during which much of the star formation has occurred. The NEWFIRM H-alpha survey covers over 1 square degree. A total of 300 H-alpha emitting galaxies at z 0.8 has been identified for 60% of the survey volume. Preliminary results from the NEWFIRM H-alpha Survey will be discussed. Spectroscopy for both narrow-band surveys reveals a high reliability of the technique: contamination at the few percent level. Finally, I will describe the first Lyman break survey to select star-forming galaxies at z 2 (limiting magnitude of 27 AB), using deep, wide GALEX near-ultraviolet imaging. A total of 7000 LBGs was identified in 0.25 square degree. Spectroscopy indicates that the success of identifying z 2 galaxies is 80%. I will also compare different z 2 photometric techniques (BzK, DRG, BX/BM) to provide a more comprehensive view of the galaxy population, including dusty star-forming galaxies. The comparison reveals a good but imperfect ( 50%) overlap, indicating that these photometric techniques are complementary.

  17. THE CHEMICAL EVOLUTION OF STAR-FORMING GALAXIES OVER THE LAST 11 BILLION YEARS

    SciTech Connect

    Zahid, H. Jabran; Kewley, Lisa J.; Geller, Margaret J.; Hwang, Ho Seong; Fabricant, Daniel G.; Kurtz, Michael J.

    2013-07-10

    We calculate the stellar mass-metallicity relation at five epochs ranging to z {approx} 2.3. We quantify evolution in the shape of the mass-metallicity relation as a function of redshift; the mass-metallicity relation flattens at late times. There is an empirical upper limit to the gas-phase oxygen abundance in star-forming galaxies that is independent of redshift. From examination of the mass-metallicity relation and its observed scatter, we show that the flattening at late times is a consequence of evolution in the stellar mass where galaxies enrich to this empirical upper metallicity limit; there is also evolution in the fraction of galaxies at a fixed stellar mass that enrich to this limit. The stellar mass where metallicities begin to saturate is {approx}0.7 dex smaller in the local universe than it is at z {approx} 0.8.

  18. 3.5 billion years of glass bioalteration: Volcanic rocks as a basis for microbial life?

    SciTech Connect

    Staudigel, H.; Furnes, H.; McLoughlin, N.; Banerjee, N.R.; Connell, L.B.; Templeton, A.

    2009-04-07

    Alteration textures in volcanic glass from the seafloor fall into two classes, one suggestive of abiotic/diffusive hydration and chemical exchange, and another likely to be caused by microbial, cavity-forming, congruent dissolution. Glass bioalteration is common in submarine lavas throughout the world's ocean, dominant in the upper 300 m of the oceanic crust, and found in all well-preserved ophiolites and greenstone belts dating back to 3.5 Ga. It may yield a significant fraction of the global biomass and geochemical fluxes and is relevant to the development of the earliest life on Earth. We present a critical review concerning these glass bioalteration textures and present new data on their microchemical environment. We explore arguments for their biogenicity and further develop the prevalent model for their formation by relating corrosion morphology to the mechanism of microbial dissolution. Biological alteration produces conspicuous micron-scale granular and tubular textures. Granular glass alteration is well explained by colonizing microbes that selectively dissolve the glass in their contact area, forming a sponge-like interconnected network of micron-sized cavities along glass surfaces. Tubular alteration meanwhile, is more likely to be caused by filamentous cell extensions in a process similar to fungal tunneling of soil feldspars and marine carbonates. While we see clear functional similarities to fungal dissolution behavior, we do not know whether fungal or prokaryotic organisms are involved. However, this functional constraint may eventually help to identify potential microbes responsible for these features, potentially including eukaryotic or prokaryotic organisms. Yet, we caution that these organisms may be difficult to identify and to study, because they are likely to be sparsely distributed, slow growing, and difficult to cultivate.

  19. On the origin, evolution, and nature of programmed cell death: a timeline of four billion years.

    PubMed

    Ameisen, J C

    2002-04-01

    Programmed cell death is a genetically regulated process of cell suicide that is central to the development, homeostasis and integrity of multicellular organisms. Conversely, the dysregulation of mechanisms controlling cell suicide plays a role in the pathogenesis of a wide range of diseases. While great progress has been achieved in the unveiling of the molecular mechanisms of programmed cell death, a new level of complexity, with important therapeutic implications, has begun to emerge, suggesting (i) that several different self-destruction pathways may exist and operate in parallel in our cells, and (ii) that molecular effectors of cell suicide may also perform other functions unrelated to cell death induction and crucial to cell survival. In this review, I will argue that this new level of complexity, implying that there may be no such thing as a 'bona fide' genetic death program in our cells, might be better understood when considered in an evolutionary context. And a new view of the regulated cell suicide pathways emerges when one attempts to ask the question of when and how they may have become selected during evolution, at the level of ancestral single-celled organisms. PMID:11965491

  20. Oxidative Weathering of Earth's Surface 3.7 Billion Years ago? - A Chromium Isotope Perspective

    NASA Astrophysics Data System (ADS)

    Frei, R.; Crowe, S.; Bau, M.; Polat, A.; Fowle, D. A.; Døssing, L. N.

    2015-12-01

    The Great Oxidation Event signals the first large-scale oxygenation of the atmosphere roughly 2.4 Gyr ago. Geochemical signals diagnostic of oxidative weathering, however, extend as far back as 3.3-2.9 Gyr ago. 3.8-3.7 Gyr old rocks from Isua, Greenland stand as a deep time outpost, recording information on Earth's earliest surface chemistry and the low oxygen primordial biosphere. We find positive Cr isotope values (average δ53Cr = +0.05 +/- 0.10 permil; δ53Cr = (53Cr/52Cr)sample/(53Cr/52Cr)SRM 979 - 1) x 1000, where SRM 979 denotes Standard Reference Material 979 in both the Fe and Si-rich mesobands of 7 compositionally distinct quartz-magnetite and magnesian banded iron formation (BIF) samples collected from the eastern portion of the Isua BIF (Western Greenland). These postively fractioned Cr isotopes, relative to the igneous silicate Earth reservoir, in metamorphosed BIFs from Isua indicate oxidative Cr cycling 3.8-3.7 Gyr ago. We also examined the distribution of U, which is immobile in its reduced state but mobile when it is oxidized. Elevated U/Th ratios (mean U/Th ratio of 0.70 ± 0.29) in these BIFs relative to the contemporary crust, also signal oxidative mobilization of U. We suggest that reactive oxygen species (ROS) accumulated in Earth's surface environment inducing the oxidative weathering of rocks during the deposition of the Isua BIFs. The precise threshold atmospheric O2 concentrations for the induction of Cr isotope fractionation remain uncertain, but we argue that our data are consistent with the very low levels of oxygen or other ROS indicated by other proxies. Importantly, any trace of Cr that cycled through redox reactions on land would tend both to be heavy, and to mobilize into the contemporaneous run-off more readily than Cr weathered directly as Cr(III). Once having reached the oceans, this fractionated Cr would have been stripped from seawater by Fe (oxy)hydroxides formed during the deposition of BIFs from low oxygen oceans. The reactive oxygen species recorded in Isua sediments may also have been sufficient to support aerobic metabolisms, which are known to occur in extant bacteria at oxygen concentrations as low as 10-8 atm.

  1. Geomagnetic field strength 3.2 billion years ago recorded by single silicate crystals.

    PubMed

    Tarduno, John A; Cottrell, Rory D; Watkeys, Michael K; Bauch, Dorothy

    2007-04-01

    The strength of the Earth's early geomagnetic field is of importance for understanding the evolution of the Earth's deep interior, surface environment and atmosphere. Palaeomagnetic and palaeointensity data from rocks formed near the boundary of the Proterozoic and Archaean eons, some 2.5 Gyr ago, show many hallmarks of the more recent geomagnetic field. Reversals are recorded, palaeosecular variation data indicate a dipole-dominated morphology and available palaeointensity values are similar to those from younger rocks. The picture before 2.8 Gyr ago is much less clear. Rocks of the Archaean Kaapvaal craton (South Africa) are among the best-preserved, but even they have experienced low-grade metamorphism. The variable acquisition of later magnetizations by these rocks is therefore expected, precluding use of conventional palaeointensity methods. Silicate crystals from igneous rocks, however, can contain minute magnetic inclusions capable of preserving Archaean-age magnetizations. Here we use a CO2 laser heating approach and direct-current SQUID magnetometer measurements to obtain palaeodirections and intensities from single silicate crystals that host magnetite inclusions. We find 3.2-Gyr-old field strengths that are within 50 per cent of the present-day value, indicating that a viable magnetosphere sheltered the early Earth's atmosphere from solar wind erosion. PMID:17410173

  2. SCORCH I: The Galaxy-Halo Connection in the First Billion Years

    NASA Astrophysics Data System (ADS)

    Trac, Hy; Cen, Renyue; Mansfield, Philip

    2015-11-01

    SCORCH (Simulations and Constructions of the Reionization of Cosmic Hydrogen) is a new project to study the Epoch of Reionization (EoR). In this first paper, we probe the connection between observed high-redshift galaxies and simulated dark matter halos to better understand the primary source of ionizing radiation. High-resolution N-body simulations are run to quantify the abundance of dark matter halos as a function of mass M, accretion rate \\dot{M}, and redshift z. A new fit for the halo mass function dn/dM is ≈20% more accurate at the high-mass end. A novel approach is used to fit the halo accretion rate function {dn}/d\\dot{M} in terms of the halo mass function. Abundance matching against the observed galaxy luminosity function is used to estimate the luminosity-mass relation and the luminosity-accretion-rate relation. The inferred star formation efficiency is not monotonic with M nor \\dot{M}, but reaches a maximum value at a characteristic mass ˜ 2× {10}11 {M}⊙ and a characteristic accretion rate ˜ 6× {10}2 {M}⊙ {{{yr}}}-1 at z ≈ 6. We find a universal EoR luminosity-accretion-rate relation and construct a fiducial model for the galaxy luminosity function. The Schechter parameters evolve such that {φ }\\star decreases, {M}\\star is fainter, and α is steeper at higher redshifts. We forecast for the upcoming James Webb Space Telescope and show that with apparent magnitude limit {m}{{AB}}≈ 31 (32), it can observe ≳ 11 (24) unlensed galaxies per square degree per unit redshift at least down to {M}\\star at z ≲ 13 (14).

  3. Plutonium-244 fission tracks - Evidence in a lunar rock 3.95 billion years old.

    NASA Technical Reports Server (NTRS)

    Hutcheon, I. D.; Price, P. B.

    1972-01-01

    Tracks attributed to the spontaneous fission of plutonium-244 and of uranium-238 were detected in a large whitlockite crystal in the lunar breccia 14321 from the Fra Mauro formation. For a track-retention age of 3.95 b.y., the number of plutonium tracks relative to the number of uranium tracks is 0.51 plus or minus 0.15, provided that the rock was not heavily neutron-irradiated 3.95 b.y. ago.

  4. Martian impact cratering rate over the last 3 billions years derived from layered ejecta craters dating

    NASA Astrophysics Data System (ADS)

    Lagain, Anthony; Bouley, Sylvain; Costard, François; Baratoux, David

    2016-04-01

    All chronology models used in dating planetary surfaces are based on the lunar chronology system. The cratering density of the Moon has been calibrated with absolute ages from Apollo lunar samples. However, there are no lunar samples between 3 Gy and 800 My and only four samples have been dated between 800 My and present. Therefore, the evolution of the cratering rate after the LHB and before 3 Gy is well constrained. The cratering rate between 3 Gy and present has been assumed to be constant [1, 2]. Nevertheless, this assumption is challenged by the analysis of the geological record, such as the frequency of landslide on Mars as a function of time [3, 4]. It is therefore necessary to re-examine the validity of this assumption and place constraints on the cratering rate since the last 3 Gy. For this purpose, we study the rate of impact cratering using small craters on a set of 53 layered ejecta craters larger than 5 km in diameter in Acidalia Planitia, Mars. LECs larger than 5km have large enough surfaces to date their formation by counting craters larger than 100m present on their blankets. Furthermore, limits of their ejecta blankets are clearly defined by a terminal bead. In order to determine the crater emplacement ages, we have applied the methodology dating described in our previous study [6] on all ejecta layers. Errors on measured ages were calculated following [7]. The age of the study area is 2.8±0.2 Gy. Our crater counts on distal ejecta blankets reveal ages younger than the age of the surrounding surface, as expected. It is essential to take into account errors on measured ages. The statistical sample used to build this emplacement frequency distribution and our dating methodology are sufficiently reliable to deduce that a constant impact cratering rate over the last 3 Gy is not a correct approximation. The excessive number of craters emplaced 1Gy ago compared to the cratering rate used suggests a decreased impact cratering rate over the last 1Gy and the presence of one or several peaks of cratering rate (possibly associated with disruption events in the asteroid belt ?). This study confirms that the assumption of a constant cratering rate for the last 3 Gy should be revised. References: [1] Hartmann W.K. (1973) JGR, 78:4096-4116. [2] Hartmann W.K. and Neukum G. (2001) Sp. Sci. Reviews, 96:165-194. [3] Hartmann W.K. (2007). Icarus, 189:274-278. [4] Quantin C. et al. (2007) Icarus, 186:1-10. [5] Hartmann W.K. (2005) Icarus, 174:294-320. [6] Lagain A. et al. (2015) LPS XLVI, Abstract #1920. [7] Levine J. et al. (2005) GRL, 32:L15201.

  5. Gusev Crater Paleolake: Two-Billion Years of Martian Geologic, (and Biologic?) History

    NASA Technical Reports Server (NTRS)

    Cabrol, N. A.; Grin, E. A.; Landheim, R.; Greeley, R.; Kuzmin, R.; McKay, C. P.

    1998-01-01

    Ancient Martian lakes are sites where the climatological, chemical, and possibly biological history of the planet has been recorded. Their potential to keep this global information in their sedimentary deposits, potential only shared with the polar layered-deposits, designates them as the most promising targets for the ongoing exploration of Mars in terms of science return and global knowledge about Mars evolution. Many of the science priority objectives of the Surveyor Program can be met by exploring ancient Martian lake beds. Among martian paleolakes, lakes in impact craters represent probably the most favorable sites to explore. Though highly destructive events when they occur, impacts may have provided in time a significant energy source for life, by generating heat, and at the contact of water and/or ice, deep hydrothermal systems, which are considered as favorable environments for life. In addition, impact crater lakes are changing environments, from thermally driven systems at the very first stage of their formation, to cold ice-protected potential oases in the more recent Martian geological times. Thus, they are plausible sites to study the progression of diverse microbiologic communities.

  6. Detection of Pristine Gas Two Billion Years After the Big Bang

    NASA Astrophysics Data System (ADS)

    Fumagalli, Michele; O'Meara, John M.; Prochaska, J. Xavier

    2011-12-01

    In the current cosmological model, only the three lightest elements were created in the first few minutes after the Big Bang; all other elements were produced later in stars. To date, however, heavy elements have been observed in all astrophysical environments. We report the detection of two gas clouds with no discernible elements heavier than hydrogen. These systems exhibit the lowest heavy-element abundance in the early universe, and thus are potential fuel for the most metal-poor halo stars. The detection of deuterium in one system at the level predicted by primordial nucleosynthesis provides a direct confirmation of the standard cosmological model. The composition of these clouds further implies that the transport of heavy elements from galaxies to their surroundings is highly inhomogeneous.

  7. A powerful toolkit for synthetic biology: Over 3.8 billion years of evolution.

    PubMed

    Rothschild, Lynn J

    2010-04-01

    The combination of evolutionary with engineering principles will enhance synthetic biology. Conversely, synthetic biology has the potential to enrich evolutionary biology by explaining why some adaptive space is empty, on Earth or elsewhere. Synthetic biology, the design and construction of artificial biological systems, substitutes bio-engineering for evolution, which is seen as an obstacle. But because evolution has produced the complexity and diversity of life, it provides a proven toolkit of genetic materials and principles available to synthetic biology. Evolution operates on the population level, with the populations composed of unique individuals that are historical entities. The source of genetic novelty includes mutation, gene regulation, sex, symbiosis, and interspecies gene transfer. At a phenotypic level, variation derives from regulatory control, replication and diversification of components, compartmentalization, sexual selection and speciation, among others. Variation is limited by physical constraints such as diffusion, and chemical constraints such as reaction rates and membrane fluidity. While some of these tools of evolution are currently in use in synthetic biology, all ought to be examined for utility. A hybrid approach of synthetic biology coupled with fine-tuning through evolution is suggested. PMID:20349441

  8. Detection of pristine gas two billion years after the Big Bang.

    PubMed

    Fumagalli, Michele; O'Meara, John M; Prochaska, J Xavier

    2011-12-01

    In the current cosmological model, only the three lightest elements were created in the first few minutes after the Big Bang; all other elements were produced later in stars. To date, however, heavy elements have been observed in all astrophysical environments. We report the detection of two gas clouds with no discernible elements heavier than hydrogen. These systems exhibit the lowest heavy-element abundance in the early universe, and thus are potential fuel for the most metal-poor halo stars. The detection of deuterium in one system at the level predicted by primordial nucleosynthesis provides a direct confirmation of the standard cosmological model. The composition of these clouds further implies that the transport of heavy elements from galaxies to their surroundings is highly inhomogeneous. PMID:22075722

  9. Could organic matter have been preserved on Mars for 3.5 billion years?

    NASA Technical Reports Server (NTRS)

    Kanavarioti, Anastassia; Mancinelli, Rocco L.

    1990-01-01

    About 3.5 Gyr ago, when it is thought that Mars and earth had similar climates, biological evolution on earth had made considerable progress, such that life was abundant. It is therefore surmised that prior to this time period, the advent of chemical evolution and subsequent origin of life occurred on earth and may have occurred on Mars. Analysis for organic compounds in the soil buried beneath the Martian surface may yield useful information regarding the occurrence of chemical evolution and possibly biological evolution. Calculations based on the stability of amino acids lead to the conclusion that remnants of these compounds, if they existed on Mars 3.5 Gyr ago, might have been preserved buried beneath the surface oxidizing layer. For example, if phenylalanine, an amino acid of average stability, existed on Mars 3.5 Gyr ago, then 1.6 percent would remain buried today. Martian soil may exist from remnants of meteoritic and cometary bombardment, assuming that 1 percent of the organics survived impact.

  10. ON THE LAST 10 BILLION YEARS OF STELLAR MASS GROWTH IN STAR-FORMING GALAXIES

    SciTech Connect

    Leitner, Samuel N.

    2012-02-01

    The star formation rate-stellar mass relation (SFR-M{sub *}) and its evolution (i.e., the SFR main sequence) describe the growth rate of galaxies of a given stellar mass and at a given redshift. Assuming that present-day star-forming galaxies (SFGs) were always star forming in the past, these growth rate observations can be integrated to calculate average star formation histories (SFHs). Using this Main Sequence Integration (MSI) approach, we trace present-day massive SFGs back to when they were 10%-20% of their current stellar mass. The integration is robust throughout those epochs: the SFR data underpinning our calculations are consistent with the evolution of stellar mass density in this regime. Analytic approximations to these SFHs are provided. Integration-based results reaffirm previous suggestions that current SFGs formed virtually all of their stellar mass at z < 2. It follows that massive galaxies observed at z > 2 are not the typical progenitors of SFGs today. We also check MSI-based SFHs against those inferred from analysis of the fossil record-from spectral energy distributions (SEDs) of SFGs in the Sloan Digital Sky Survey and color-magnitude diagrams (CMDs) of resolved stars in dwarf irregular galaxies. Once stellar population age uncertainties are accounted for, the main sequence is in excellent agreement with SED-based SFHs (from VESPA). Extrapolating SFR main sequence observations to dwarf galaxies, we find differences between MSI results and SFHs from CMD analysis of Advanced Camera for Surveys Nearby Galaxy Survey Treasury and Local Group galaxies. Resolved dwarfs appear to grow much slower than main sequence trends imply, and also slower than slightly higher mass SED-analyzed galaxies. This difference may signal problems with SFH determinations, but it may also signal a shift in star formation trends at the lowest stellar masses.