Science.gov

Sample records for questionable impact origin

  1. A glass spherule of questionable impact origin from the Apollo 15 landing site: Unique target mare basalt

    USGS Publications Warehouse

    Ryder, G.; Delano, J.W.; Warren, P.H.; Kallemeyn, G.W.; Dalrymple, G.B.

    1996-01-01

    A 6 mm-diameter dark spherule, 15434,28, from the regolith on the Apennine Front at the Apollo 15 landing site has a homogeneous glass interior with a 200 ??m-thick rind of devitrified or crystallized melt. The rind contains abundant small fragments of Apollo 15 olivine-normative mare basalt and rare volcanic Apollo 15 green glass. The glass interior of the spherule has the chemical composition, including a high FeO content and high CaO/Al2O3, of a mare basalt. Whereas the major element and Sc, Ni, and Co abundances are similar to those of low-Ti mare basalts, the incompatible elements and Sr abundances are similar to those of high-Ti mare basalts. The relative abundance patterns of the incompatible trace elements are distinct from any other lunar mare basalts or KREEP; among these distinctions are a much steeper slope of the heavy rare earth elements. The 15434,28 glass has abundances of the volatile element Zn consistent with both impact glasses and crystalline mare basalts, but much lower than in glasses of mare volcanic origin. The glass contains siderophile elements such as Ir in abundances only slightly higher than accepted lunar indigenous levels, and some, such as Au, are just below such upper limits. The age of the glass, determined by the 40Ar/39Ar laser incremental heating technique, is 1647 ?? 11 Ma (2 ??); it is expressed as an age spectrum of seventeen steps over 96% of the 39Ar released, unusual for an impact glass. Trapped argon is negligible. The undamaged nature of the sphere demonstrates that it must have spent most of its life buried in regolith; 38Ar cosmic ray exposure data suggest that it was buried at less than 2m but more than a few centimeters if a single depth is appropriate. That the spherule solidified to a glass is surprising; for such a mare composition, cooling at about 50??C s-1 is required to avoid crystallization, and barely attainable in such a large spherule. The low volatile abundances, slightly high siderophile abundances, and

  2. A Glass Spherule of Questionable Impact Origin from the Apollo 15 Landing Site: Unique Target Mare Basalt

    NASA Technical Reports Server (NTRS)

    Ryder, Graham; Delano, John W.; Warren, Paul H.; Kallemeyn, Gregory W.; Dalrymple, G. Brent

    1996-01-01

    A 6 mm-diameter dark spherule, 15434,28, from the regolith on the Apennine Front at the Apollo 15 landing site has a homogeneous glass interior with a 200 microns-thick rind of devitrified or crystallized melt. The rind contains abundant small fragments of Apollo 15 olivine-normative mare basalt and rare volcanic Apollo 15 green glass. The glass interior of the spherule has the chemical composition, including a high FeO content and high CaO/Al2O3, of a mare basalt. Whereas the major element and Sc, Ni, and Co abundances are similar to those of low-Ti mare basalts, the incompatible elements and Sr abundances are similar to those of high-Ti mare basaits. The relative abundance patterns of the incompatible trace elements are distinct from any other lunar mare basalts or KREEP; among these distinctions are a much steeper slope of the heavy rare earth elements. The 15434,28 glass has abundances of the volatile element Zn consistent with both impact glasses and crystalline mare basalts, but much lower than in glasses of mare volcanic origin. The glass contains siderophile elements such as Ir in abundances only slightly higher than accepted lunar indigenous levels, and some, such as Au, are just below such upper limits. The age of the glass, determined by the Ar-40/Ar-39 laser incremental heating technique, is 1647 +/- 11 Ma (2 sigma); it is expressed as an age spectrum of seventeen steps over 96% of the Ar-38 released, unusual for an impact glass. Trapped argon is negligible. The undamaged nature of the sphere demonstrates that it must have spent most of its life buried in regolith; Ar-38 cosmic ray exposure data suggest that it was buried at less than 2m but more than a few centimeters if a single depth is appropriate. That the spherule solidified to a glass is surprising; for such a mare composition, cooling at about 50 C/s is required to avoid crystallization, and barely attainable in such a large spherule. The low volatile abundances, slightly high siderophile

  3. Open Questions on the Origin of Eukaryotes.

    PubMed

    López-García, Purificación; Moreira, David

    2015-11-01

    Despite recent progress, the origin of the eukaryotic cell remains enigmatic. It is now known that the last eukaryotic common ancestor was complex and that endosymbiosis played a crucial role in eukaryogenesis at least via the acquisition of the alphaproteobacterial ancestor of mitochondria. However, the nature of the mitochondrial host is controversial, although the recent discovery of an archaeal lineage phylogenetically close to eukaryotes reinforces models proposing archaea-derived hosts. We argue that, in addition to improved phylogenomic analyses with more comprehensive taxon sampling to pinpoint the closest prokaryotic relatives of eukaryotes, determining plausible mechanisms and selective forces at the origin of key eukaryotic features, such as the nucleus or the bacterial-like eukaryotic membrane system, is essential to constrain existing models.

  4. Open questions on the origin of eukaryotes

    PubMed Central

    López-García, Purificación; Moreira, David

    2015-01-01

    Despite recent progress, the origin of the eukaryotic cell remains enigmatic. It is now known that the last eukaryotic common ancestor was complex and that endosymbiosis played a crucial role in eukaryogenesis at least via the acquisition of the alphaproteobacterial ancestor of mitochondria. However, the nature of the mitochondrial host is controversial, although the recent discovery of an archaeal lineage phylogenetically close to eukaryotes reinforces models proposing archaea-derived hosts. We argue that, in addition to improved phylogenomic analyses with more comprehensive taxon sampling to pinpoint the closest prokaryotic relatives of eukaryotes, determining plausible mechanisms and selective forces at the origin of key eukaryotic features, such as the nucleus or the bacterial-like eukaryotic membrane system, is essential to constrain existing models. PMID:26455774

  5. Impact Origin of the Moon?

    NASA Astrophysics Data System (ADS)

    Asphaug, Erik

    2014-05-01

    Earth formed in a series of giant impacts, and the last one made the Moon. This idea, an edifice of post-Apollo science, can explain the Moon's globally melted silicate composition, its lack of water and iron, and its anomalously large mass and angular momentum. But the theory is seriously called to question by increasingly detailed geochemical analysis of lunar rocks. Lunar samples should be easily distinguishable from Earth, because the Moon derives mostly from the impacting planet, in standard models of the theory. But lunar rocks are the same as Earth in O, Ti, Cr, W, K, and other species, to measurement precision. Some regard this as a repudiation of the theory; others say it wants a reformation. Ideas put forward to salvage or revise it are evaluated, alongside their relationships to past models and their implications for planet formation and Earth.

  6. Impact origin of the Moon

    SciTech Connect

    Slattery, W.L.

    1998-12-31

    A few years after the Apollo flights to the Moon, it became clear that all of the existing theories on the origin of the Moon would not satisfy the growing body of constraints which appeared with the data gathered by the Apollo flights. About the same time, researchers began to realize that the inner (terrestrial) planets were not born quietly -- all had evidences of impacts on their surfaces. This fact reinforced the idea that the planets had formed by the accumulation of planetesimals. Since the Earth`s moon is unique among the terrestrial planets, a few researchers realized that perhaps the Moon originated in a singular event; an event that was quite probable, but not so probable that one would expect all the terrestrial planets to have a large moon. And thus was born the idea that a giant impact formed the Moon. Impacts would be common in the early solar system; perhaps a really large impact of two almost fully formed planets of disparate sizes would lead to material orbiting the proto-earth, a proto-moon. This idea remained to be tested. Using a relatively new, but robust, method of doing the hydrodynamics of the collision (Smoothed-Particle Hydrodynamics), the author and his colleagues (W. Benz, Univ. of Arizona, and A.G.W. Cameron, Harvard College Obs.) did a large number of collision simulations on a supercomputer. The author found two major scenarios which would result in the formation of the Moon. The first was direct formation; a moon-sized object is boosted into orbit by gravitational torques. The second is when the orbiting material forms a disk, which, with subsequent evolution can form the Moon. In either case the physical and chemical properties of the newly formed Moon would very neatly satisfy the physical and chemical constraints of the current Moon. Also, in both scenarios the surface of the Earth would be quite hot after the collision. This aspect remains to be explored.

  7. New answers prompt new questions regarding cell of origin

    PubMed Central

    De Marzo, Angelo M.; Nelson, William G.; Bieberich, Charles J.; Yegnasubramanian, Srinivasan

    2015-01-01

    Controversies remain regarding the precise cell type from which prostate cancers originate. In the last 2 years, two separate studies have arrived at apparently conflicting models for the cell type involved in prostate cancer initiation. However, these results are not mutually exclusive: there are potential solutions, and alternative views on the initiating cell derivation of prostate tumors also exist. PMID:21139640

  8. Question 1: origin of life and the living state.

    PubMed

    Kauffman, Stuart

    2007-10-01

    The aim of this article is to discuss four topics: First, the origin of molecular reproduction. Second, the origin of agency - the capacity of a system to act on its own behalf. Agency is a stunning feature of human and some wider range of life. Third, to discuss a still poorly articulated feature of life noticed by the philosopher Immanuel Kant over 200 years ago: A self propagating organization of process. We have no theory for this aspect of life, yet it is central to life. Fourth, I will discuss constraints, as in Schroedinger's aperiodic crystal (Schroedinger E, What is life? The physical aspect of the living cell, 1944), as information, part of the total non-equilibrium union of matter, energy, work, work cycles, constraints, and information that appear to comprise the living state.

  9. Question 1: Origin of Life and the Living State

    NASA Astrophysics Data System (ADS)

    Kauffman, Stuart

    2007-10-01

    The aim of this article is to discuss four topics: First, the origin of molecular reproduction. Second, the origin of agency the capacity of a system to act on its own behalf. Agency is a stunning feature of human and some wider range of life. Third, to discuss a still poorly articulated feature of life noticed by the philosopher Immanuel Kant over 200 years ago: A self propagating organization of process. We have no theory for this aspect of life, yet it is central to life. Fourth, I will discuss constraints, as in Schroedinger’s aperiodic crystal (Schroedinger E, What is life? The physical aspect of the living cell, 1944), as information, part of the total non-equilibrium union of matter, energy, work, work cycles, constraints, and information that appear to comprise the living state.

  10. Impacts and the origin of life

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.

    1990-01-01

    As living creatures, all of us have some interest in the question of how life originated. To some, the question is more religious than scientific; nonetheless, a small but dedicated group of scientists spend their careers trying to answer it from a rational standpoint. Logically, the question can be broken down into the three standard divisions of any mystery: When did life originate? Where did it originate? And how did it originate? Of these three sub-questions the last is by far the most difficult and I will make no attempt to address it here. I will however take a personal look at the two easier parts of the problem. In particular, I will outline my current view of the physical environment of the early Earth, and I will try to show how observations of other solar system bodies, especially our own Moon, provide clues as to when and where life could have originated.

  11. Experimental U.S. Census Bureau Race and Hispanic Origin Survey Questions: Reactions from Spanish Speakers

    ERIC Educational Resources Information Center

    Terry, Rodney L.; Fond, Marissa

    2013-01-01

    People of Hispanic origin, including monolingual Spanish speakers, have experienced difficulty identifying with a race category on U.S. demographic surveys. As part of a larger research effort by the U.S. Census Bureau to improve race and Hispanic origin questions for the 2020 Census, we tested experimental versions of race and Hispanic origin…

  12. Moon origin - The impact-trigger hypothesis

    NASA Technical Reports Server (NTRS)

    Hartmann, William K.

    1986-01-01

    Arguments in favor of the impact-trigger model of lunar origin are presented. Lunar properties favoring this hypothesis include: (1) lunar iron and volatile deficiency; (2) angular momentum of the earth-moon system; and (3) similar O isotopes, bulk iron contents, and densities of earth's mantle and the moon. It is shown that the intense early bombardment averaged during earth's formation was several billion times the present meteoritic mass flux, consistent with a giant impact.

  13. Impact origin of the Sudbury structure: Evolution of a theory

    NASA Technical Reports Server (NTRS)

    Lowman, Paul D., Jr.

    1992-01-01

    This paper reviews the origin, development, and present status of the widely accepted theory, proposed by Robert S. Dietz in 1962, that the Sudbury structure was formed by meteoritic or asteroidal impact. The impact theory for the origin of the Sudbury structure seems supported by a nearly conclusive body of evidence. However, even assuming an impact origin to be correct, at least three major questions require further study: (1) the original size and shape of the crater, before tectonic deformation and erosion; (2) the source of the melt now forming the Sudbury Igneous Complex; and (3) the degree, if any, to which the Ni-Cu-platinum group elements are meteoritic. The history of the impact theory illustrates several under-appreciated aspects of scientific research: (1) the importance of cross-fertilization between space research and terrestrial geology; (2) the role of the outsider in stimulating thinking by insiders; (3) the value of small science, at least in the initial stages of an investigation, Dietz's first field work having been at his own expense; and (4) the value of analogies (here, between the Sudbury Igneous Complex and the maria), which although incorrect in major aspects, may trigger research on totally new lines. Finally, the Sudbury story illustrates the totally unpredictable and, by implication, unplannable nature of basic research, in that insight to the origin of the world's then-greatest Ni deposit came from the study of tektites and the Moon.

  14. Impact jetting as the origin of chondrules.

    PubMed

    Johnson, Brandon C; Minton, David A; Melosh, H J; Zuber, Maria T

    2015-01-15

    Chondrules are the millimetre-scale, previously molten, spherules found in most meteorites. Before chondrules formed, large differentiating planetesimals had already accreted. Volatile-rich olivine reveals that chondrules formed in extremely solid-rich environments, more like impact plumes than the solar nebula. The unique chondrules in CB chondrites probably formed in a vapour-melt plume produced by a hypervelocity impact with an impact velocity greater than 10 kilometres per second. An acceptable formation model for the overwhelming majority of chondrules, however, has not been established. Here we report that impacts can produce enough chondrules during the first five million years of planetary accretion to explain their observed abundance. Building on a previous study of impact jetting, we simulate protoplanetary impacts, finding that material is melted and ejected at high speed when the impact velocity exceeds 2.5 kilometres per second. Using a Monte Carlo accretion code, we estimate the location, timing, sizes, and velocities of chondrule-forming impacts. Ejecta size estimates indicate that jetted melt will form millimetre-scale droplets. Our radiative transfer models show that these droplets experience the expected cooling rates of ten to a thousand kelvin per hour. An impact origin for chondrules implies that meteorites are a byproduct of planet formation rather than leftover building material.

  15. Impact jetting as the origin of chondrules.

    PubMed

    Johnson, Brandon C; Minton, David A; Melosh, H J; Zuber, Maria T

    2015-01-15

    Chondrules are the millimetre-scale, previously molten, spherules found in most meteorites. Before chondrules formed, large differentiating planetesimals had already accreted. Volatile-rich olivine reveals that chondrules formed in extremely solid-rich environments, more like impact plumes than the solar nebula. The unique chondrules in CB chondrites probably formed in a vapour-melt plume produced by a hypervelocity impact with an impact velocity greater than 10 kilometres per second. An acceptable formation model for the overwhelming majority of chondrules, however, has not been established. Here we report that impacts can produce enough chondrules during the first five million years of planetary accretion to explain their observed abundance. Building on a previous study of impact jetting, we simulate protoplanetary impacts, finding that material is melted and ejected at high speed when the impact velocity exceeds 2.5 kilometres per second. Using a Monte Carlo accretion code, we estimate the location, timing, sizes, and velocities of chondrule-forming impacts. Ejecta size estimates indicate that jetted melt will form millimetre-scale droplets. Our radiative transfer models show that these droplets experience the expected cooling rates of ten to a thousand kelvin per hour. An impact origin for chondrules implies that meteorites are a byproduct of planet formation rather than leftover building material. PMID:25592538

  16. 75 FR 53971 - Guidance for Industry and Food and Drug Administration Staff; Impact-Resistant Lenses: Questions...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-02

    ...; Impact-Resistant Lenses: Questions and Answers; Availability AGENCY: Food and Drug Administration, HHS... guidance entitled ``Impact-Resistant Lenses: Questions and Answers.'' This guidance document answers manufacturer, importer, and consumer questions on impact-resistant lenses, including questions on...

  17. An open question on the origin of life: the first forms of metabolism.

    PubMed

    Luisi, Pier Luigi

    2012-11-01

    The general framework of the origin of life on Earth is outlined, emphasizing that the so-called prebiotic 'RNA world' is as yet on shaky scientific ground, and that one should any way ask the question of the structure of the first protocellular compartments capable of the initial forms of metabolism. This question is the basis of the research project on the minimal cells, containing the minimal and sufficient complexity capable of leading to life. Such research is briefly summarized, highlighting experiments with liposome-based semisynthetic cells which are capable of ribosomal protein synthesis with a very minimal number of enzymes. The most recent finding in this area of research is the unexpected observation that the formation and closure of liposomes in situ acts as an attractor for the solute molecules in solution, bringing about a very high local concentration in some of the liposomes. It is argued that this spontaneous overcrowding, which permits reactions which are not possible in the original dilute solution, might be the origin of cellular metabolism for the origin of life on Earth.

  18. Impacts and the origin of life

    NASA Technical Reports Server (NTRS)

    Oberbeck, Verne R.; Fogleman, Guy

    1989-01-01

    Consideration is given to the estimate of Maher and Stevenson (1988) of the time at which life could have developed on earth through chemical evolution within a time interval between impact events, assuming chemical or prebiotic evolution times of 100,000 to 10,000,000 yrs. An error in the equations used to determine the time periods between impact events in estimating this time is noted. A revised equation is presented and used to calculate the point in time at which impact events became infrequent enough for life to form. By using this equation, the finding of Maher and Stevenson that life could have first originated between 4,100 and 4,300 million years ago is changed to 3,700 to 4,000 million years ago.

  19. Question 2: why an astrobiological study of titan will help us understand the origin of life.

    PubMed

    Raulin, Francois

    2007-10-01

    For understanding the origin(s) of life on Earth it is essential to search for and study extraterrestrial environments where some of the processes which participated in the emergence of Life on our planet are still occurring. This is one of the goals of astrobiology. In that frame, the study of extraterrestrial organic matter is essential and is certainly not of limited interest regarding prebiotic molecular evolution. Titan, the largest satellite of Saturn and the only planetary body with an atmosphere similar to that of the Earth is one of the places of prime interest for these astrobiological questions. It presents many analogies with the primitive Earth, and is a prebiotic-like laboratory at the planetary scale, where a complex organic chemistry in is currently going on.

  20. The ultimate question of origins: God and the beginning of the Universe.

    NASA Astrophysics Data System (ADS)

    Craig, W. L.

    Both cosmology and philosophy trace their roots to the wonder felt by the ancient Greeks as they contemplated the Universe. The ultimate question remains why the Universe exists rather than nothing. This question led Leibniz to postulate the existence of a metaphysically necessary being, which he identified as God. Leibniz's critics, however, disputed this identification, claiming that the space-time universe itself may be the metaphysically necessary being. The discovery during this century that the Universe began to exist, however, calls into question the Universe's status as metaphysically necessary, since any necessary being must be eternal in its existence. Although various cosmogonic models claiming to avert the beginning of the Universe predicted by the standard model have been and continue to be offered, no model involving an eternal universe has proved as plausible as the standard model. Unless we are to assert that the Universe simply sprang into being uncaused out of nothing, we are thus led to Leibniz's conclusion. Several objections to inferring a supernatural cause of the origin of the Universe are considered and found to be unsound.

  1. The Ultimate Question of Origins: God and the Beginning of the Universe

    NASA Astrophysics Data System (ADS)

    Craig, William Lane

    1999-12-01

    Both cosmology and philosophy trace their roots to the wonder felt by the ancient Greeks as they contemplated the universe. The ultimate question remains why the universe exists rather than nothing. This question led Leibniz to postulate the existence of a metaphysically necessary being, which he identified as God. Leibniz's critics, however, disputed this identification, claiming that the space-time universe itself may be the metaphysically necessary being. The discovery during this century that the universe began to exist, however, calls into question the universe's status as metaphysically necessary, since any necessary being must be eternal in its existence. Although various cosmogonic models claiming to avert the beginning of the universe predicted by the standard model have been and continue to be offered, no model involving an eternal universe has proved as plausible as the standard model. Unless we are to assert that the universe simply sprang into being uncaused out of nothing, we are thus led to Leibniz's conclusion. Several objections to inferring a supernatural cause of the origin of the universe are considered and found to be unsound.

  2. Ethnic Origins 3: An Experiment in the Use of a Direct Question about Ethnicity, for the Census. Occasional Paper 10.

    ERIC Educational Resources Information Center

    Sillitoe, Ken

    This is a report on the third effort to formulate an effective question for determining the ethnicity of respondents to Great Britain's 1981 census. Discussed herein is the response to the ethnic origins questions, different versions of which were incorporated into the main census pre-test and administered to 4250 households (including large…

  3. Open Questions on the Origin of Life at Anoxic Geothermal Fields

    PubMed Central

    Mulkidjanian, Armen Y.; Bychkov, Andrew Yu.; Dibrova, Daria V.; Galperin, Michael Y.; Koonin, Eugene V.

    2014-01-01

    We have recently reconstructed the ‘hatcheries’ of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells (Mulkidjanian et al.: Origin of first cells at terrestrial, anoxic geothermal fields. Proc Natl Acad Sci USA 2012, 109:E821–830). These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K+, Zn2+, Mn2+, and phosphate. Thus, protocells must have evolved in habitats with a high K+/Na+ ratio and relatively high concentrations of Zn, Mn and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under anoxic, CO2-dominated atmosphere, the ionic composition of pools of cool, condensed vapor at anoxic geothermal fields would resemble the internal milieu of modern cells. Such pools would be lined with porous silicate minerals mixed with metal sulfides and enriched in K+ ions and phosphorous compounds. Here we address some questions that have appeared in print after the publication of our anoxic geothermal field scenario. We argue that anoxic geothermal fields, which were identified as likely cradles of life by using a top-down approach and phylogenomics analysis as a tool, could provide geochemical conditions similar to those which were suggested as most conducive for the emergence of life by the chemists who pursuit the complementary bottom-up strategy. PMID:23132762

  4. Study questions environmental impact of fuel-cell vehicles

    NASA Astrophysics Data System (ADS)

    Stafford, Ned

    2015-09-01

    Fuel-cell electric vehicles are seen by many as an environmentally friendly technology that can reduce greenhousegas emissions by producing no harmful emissions. But a new study has found that overall a fuel cell electric vehicle has about the same negative environmental impact as a luxury sports car.

  5. Open questions on the origin of life at anoxic geothermal fields.

    PubMed

    Mulkidjanian, Armen Y; Bychkov, Andrew Yu; Dibrova, Daria V; Galperin, Michael Y; Koonin, Eugene V

    2012-10-01

    We have recently reconstructed the 'hatcheries' of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells (Mulkidjanian et al. Proc Natl Acad Sci U S A 109:E821-830, 2012). These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K⁺, Zn²⁺, Mn²⁺, and phosphate. Thus, protocells must have evolved in habitats with a high K⁺/Na⁺ ratio and relatively high concentrations of Zn, Mn and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under an anoxic, CO₂-dominated atmosphere, the ionic composition of pools of cool, condensed vapor at anoxic geothermal fields would resemble the internal milieu of modern cells. Such pools would be lined with porous silicate minerals mixed with metal sulfides and enriched in K⁺ ions and phosphorous compounds. Here we address some questions that have appeared in print after the publication of our anoxic geothermal field scenario. We argue that anoxic geothermal fields, which were identified as likely cradles of life by using a top-down approach and phylogenomics analysis, could provide geochemical conditions similar to those which were suggested as most conducive for the emergence of life by the chemists who pursuit the complementary bottom-up strategy.

  6. Growth Impacts on Public Service Expenditures: Some Questions for the Community. Coping with Growth.

    ERIC Educational Resources Information Center

    Rimbey, Neil R.

    Defining public services as the basic community/regional services which are provided to residents through tax receipts and service charges, this publication identifies variables for each service group and presents them in the form of questions that communities should find useful when analyzing impacts of growth. After listing questions dealing…

  7. Understanding origins and impacts of drought

    NASA Astrophysics Data System (ADS)

    Loboda, Tatiana; Krankina, Olga; Kurbanov, Eldar

    2012-10-01

    Impacts of Extreme Weather on Natural, Socio-economic, and Land-Use Systems:Focus on the 2010 Summer Anomaly in the Volga Region;Yoshkar-Ola, Russia, 17-21 June 2012 In the summer of 2010 an extreme drought captured the attention of the media, the Russian government, and the international community. This drought resulted in widespread crop failure within one of the largest wheat-exporting regions of the world, leading to global grain price hikes. A joint NASA, Global Observations of Forest and Land Cover Dynamics (GOFC-GOLD), and Northern Eurasia Earth Science Partnership Initiative (NEESPI) meeting at the Volga State University of Technology, held 2 years after the 2010 drought, provided for a wide-ranging and in-depth review of recent research on the drought and its impacts on ecosystems and society and drew participants from the United States, Europe, Russia, and Kazakhstan.

  8. Origins and impacts of new mammalian exons

    PubMed Central

    Merkin, Jason; Chen, Ping; Alexis, Maria; Hautaniemi, Sampsa; Burge, Christopher B.

    2016-01-01

    Summary Mammalian genes are composed of exons, but the evolutionary origins and functions of new internal exons are poorly understood. Here, we analyzed patterns of exon gain using deep cDNA sequencing data from five mammals and one bird, identifying thousands of species- and lineage-specific exons. Most new exons derived from unique rather than repetitive intronic sequence. Unlike exons conserved across mammals, species-specific internal exons were mostly located in 5' untranslated regions and alternatively spliced. They were associated with upstream intronic deletions, increased nucleosome occupancy, and RNA polymerase II pausing. Genes containing new internal exons had increased gene expression, but only in tissues where the exon was included. Increased expression correlated with level of exon inclusion, promoter proximity, and signatures of cotranscriptional splicing. Together these findings suggest that splicing at the 5' ends of genes enhances expression and that changes in 5' end splicing alter gene expression between tissues and between species. PMID:25801031

  9. Examining the Impact of Question Surface Features on Students' Answers to Constructed-Response Questions on Photosynthesis

    ERIC Educational Resources Information Center

    Weston, Michele; Haudek, Kevin C.; Prevost, Luanna; Urban-Lurain, Mark; Merrill, John

    2015-01-01

    One challenge in science education assessment is that students often focus on surface features of questions rather than the underlying scientific principles. We investigated how student written responses to constructed-response questions about photosynthesis vary based on two surface features of the question: the species of plant and the order of…

  10. Open questions in origin of life: experimental studies on the origin of nucleic acids and proteins with specific and functional sequences by a chemical synthetic biology approach.

    PubMed

    Adamala, Katarzyna; Anella, Fabrizio; Wieczorek, Rafal; Stano, Pasquale; Chiarabelli, Cristiano; Luisi, Pier Luigi

    2014-01-01

    In this mini-review we present some experimental approaches to the important issue in the origin of life, namely the origin of nucleic acids and proteins with specific and functional sequences. The formation of macromolecules on prebiotic Earth faces practical and conceptual difficulties. From the chemical viewpoint, macromolecules are formed by chemical pathways leading to the condensation of building blocks (amino acids, or nucleotides) in long-chain copolymers (proteins and nucleic acids, respectively). The second difficulty deals with a conceptual problem, namely with the emergence of specific sequences among a vast array of possible ones, the huge "sequence space", leading to the question "why these macromolecules, and not the others?" We have recently addressed these questions by using a chemical synthetic biology approach. In particular, we have tested the catalytic activity of small peptides, like Ser-His, with respect to peptide- and nucleotides-condensation, as a realistic model of primitive organocatalysis. We have also set up a strategy for exploring the sequence space of random proteins and RNAs (the so-called "never born biopolymer" project) with respect to the production of folded structures. Being still far from solved, the main aspects of these "open questions" are discussed here, by commenting on recent results obtained in our groups and by providing a unifying view on the problem and possible solutions. In particular, we propose a general scenario for macromolecule formation via fragment-condensation, as a scheme for the emergence of specific sequences based on molecular growth and selection.

  11. Recent discoveries of new hantaviruses widen their range and question their origins.

    PubMed

    Henttonen, Heikki; Buchy, Philippe; Suputtamongkol, Yupin; Jittapalapong, Sathaporn; Herbreteau, Vincent; Laakkonen, Juha; Chaval, Yannick; Galan, Maxime; Dobigny, Gauthier; Charbonnel, Nathalie; Michaux, Johan; Cosson, Jean-François; Morand, Serge; Hugot, Jean-Pierre

    2008-12-01

    Hantaviruses belong to the Bunyaviridae family. While usually hosted by wild mammals, they are potentially pathogenic for humans, and several serologically distinct groups associated with different syndromes have been identified. Yet, investigations have mostly been conducted where human infections by hantaviruses constitute a real and well-identified public health problem, i.e., the holarctic and neotropical areas. Some hantaviruses have also been described from a Suncus murinus in India and a Bandicota indica in Thailand. In addition, recent investigations in Cambodia revealed new Hantavirus types. More recently, two new Hantavirus species were described: Sangassou from a Hylomyscus simus, and Tanganya from a Crocidura theresae, both from Africa (Guinea), thus strongly questioning the current views about geographic range, evolution, and epidemiology of hantaviruses. In such a framework, we have conducted a survey of Hantavirus diversity in Southeast Asia which allows us to isolate the Thailand virus and address questions about the taxonomy of their rodent hosts. Here we present a molecular analysis of representatives of all currently known Hantavirus species, thus allowing the comparison between the newly described ones with a large range sample of rodent hantaviruses. Our results clearly point to the presence of a particular lineage of hantaviruses in Southeast Asia. It also strongly suggests that new viruses, additional mammalian hosts and different related syndromes in humans are likely to be discovered in the near future, particularly in Southeast Asia and in Africa, where Muridae rodents are highly diversified. Furthermore, additional work is also urgently needed to investigate the hantaviruses associated with Crociduridae and Soricidae.

  12. Question 1: Peptide nucleic acids and the origin and homochirality of life.

    PubMed

    Nielsen, Peter E

    2007-10-01

    The possibilities of pseudo peptide DNA mimics like PNA (peptide nucleic acid) having a role for the prebiotic origin of life prior to an RNA world is discussed. In particular a scenario is proposed in which protocells with an achiral genetic material through several generations stepwise is converted into a chiral genetic material, e.g., by incorporation of RNA units. Provided that a sufficiently large sequence space is occupied, a selection process based on catalytic function in which a single cell (first common ancestor) has a definite evolutionary advantage, selection of this cell would by contingency also lock it into homochirality.

  13. Question 1: Peptide Nucleic Acids and the Origin and Homochirality of Life

    NASA Astrophysics Data System (ADS)

    Nielsen, Peter E.

    2007-10-01

    The possibilities of pseudo peptide DNA mimics like PNA (peptide nucleic acid) having a role for the prebiotic origin of life prior to an RNA world is discussed. In particular a scenario is proposed in which protocells with an achiral genetic material through several generations stepwise is converted into a chiral genetic material, e.g., by incorporation of RNA units. Provided that a sufficiently large sequence space is occupied, a selection process based on catalytic function in which a single cell (first common ancestor) has a definite evolutionary advantage, selection of this cell would by contingency also lock it into homochirality.

  14. Compound-specific isotope analysis: Questioning the origins of a trichloroethene plume

    USGS Publications Warehouse

    Eberts, S.M.; Braun, C.; Jones, S.

    2008-01-01

    Stable carbon isotope ratios of trichloroethene (TCE), cis-1,2- dichloroethene, and trans-1,2-dichloroethene were determined by use of gas chromatography-combustion-isotope ratio mass spectroscopy to determine whether compound-specific stable carbon isotopes could be used to help understand the origin and history of a TCE groundwater plume in Fort Worth, TX. Calculated ??13C values for total chlorinated ethenes in groundwater samples, which can approximate the ??13C of a spilled solvent if all degradation products are accounted for, were useful for determining whether separate lobes of the plume resulted from different sources. Most notably, values for one lobe, where tetrachloroethene (PCE) has been detected periodically, were outside the range for manufactured TCE but within the range for manufactured PCE, whereas values for a separate lobe, which is downgradient of reported TCE spills, were within the range for manufactured TCE. Copyright ?? Taylor & Francis Group, LLC.

  15. Mars 2001 Mission: Addressing Scientific Questions Regarding the Characteristics and Origin of Local Bedrock and Soil

    NASA Technical Reports Server (NTRS)

    Saunders, R. S.; Arvidson, R. E.; Weitz, C. M.; Marshall, J.; Squyres, S. W.; Christensen, P. R.; Meloy, T.; Smith, P.

    1999-01-01

    The Mars Surveyor Program 2001 Mission will carry instruments on the orbiter, lander and rover that will support synergistic observations and experiments to address important scientific questions regarding the local bedrock and soils. The martian surface is covered in varying degrees by fine materials less than a few mms in size. Viking and Pathfinder images of the surface indicate that soils at those sites are composed of fine particles. Wheel tracks from the Sojourner rover suggest that soil deposits are composed of particles <40 mm. Viking images show that dunes are common in many areas on Mars and new MOC images indicate that dunes occur nearly everywhere. Dunes on Mars are thought to be composed of 250-500 microns particles based upon Viking IRTM data and Mars wind tunnel experiments. If martian dunes are composed of sand particles > 100 microns and soils are dominated by <10 micron particles, then where are the intermediate grain sizes? Have they been wom away through prolonged transport over the eons? Were they never generated to begin with? Or are they simply less easy to identify because do they not form distinctive geomorphic features such as dunes or uniform mantles that tend to assume superposition in the soil structure?

  16. The Impact of Initial Teacher Education on Understandings of Physical Education: Asking the Right Question

    ERIC Educational Resources Information Center

    Chroinin, Deirdre Ni; Coulter, Maura

    2012-01-01

    Evaluation of professional socialisation can provide insight on the impact of Physical Education Teacher Education. A large-scale (n=326) single question "What is PE?" qualitative methodology was used to access pre-service primary teachers' understandings of the nature and purpose of physical education . Data analysis involved word frequency…

  17. "Finding Useful Questions: On Bayesian Diagnosticity, Probability, Impact, and Information Gain": Correction to Nelson (2005)

    ERIC Educational Resources Information Center

    Nelson, Jonathan D.

    2007-01-01

    Reports an error in "Finding Useful Questions: On Bayesian Diagnosticity, Probability, Impact, and Information Gain" by Jonathan D. Nelson (Psychological Review, 2005[Oct], Vol 112[4], 979-999). In Table 13, the data should indicate that 7% of females had short hair and 93% of females had long hair. The calculations and discussion in the article…

  18. Origin and evolution of gnathostome dentitions: a question of teeth and pharyngeal denticles in placoderms.

    PubMed

    Zerina, Johanson; Smith, Moya M

    2005-05-01

    The fossil group Placodermi is the most phylogenetically basal of the clade of jawed vertebrates but lacks a marginal dentition comparable to that of the dentate Chondrichthyes, Acanthodii and Osteichthyes (crown-group Gnathostomata). The teeth of crown-group gnathostomes are part of an ordered dentition replaced from, and patterned by, a dental lamina, exemplified by the elasmobranch model. A dentition recognised by these criteria has been previously judged absent in placoderms, based on structural evidence such as absence of tooth whorls and typical vertebrate dentine. However, evidence for regulated tooth addition in a precise spatiotemporal order can be observed in placoderms, but significantly, only within the group Arthrodira. In these fossils, as in other jawed vertebrates with statodont, non-replacing dentitions, new teeth are added at the ends of rows below the bite, but in line with biting edges of the dentition. The pattern is different on each gnathal bone and probably arises from single odontogenic primordia on each, but tooth rows are arranged in a distinctive placoderm pattern. New teeth are made of regular dentine comparable to that of crown-gnathostomes, formed from a pulp cavity. This differs from semidentine previously described for placoderm gnathalia, a type present in the external dermal tubercles. The Arthrodira is a derived taxon within the Placodermi, hence origin of teeth in placoderms occurs late in the phylogeny and teeth are convergently derived, relative to those of other jawed vertebrates. More basal placoderm taxa adopted other strategies for providing biting surfaces and these vary substantially, but include addition of denticles to the growing gnathal plates, at the margins of pre-existing denticle patches. These alternative strategies and apparent absence of regular dentine have led to previous interpretations that teeth were entirely absent from the placoderm dentition. A consensus view emerged that a dentition, as developed

  19. Open questions in origin of life: experimental studies on the origin of nucleic acids and proteins with specific and functional sequences by a chemical synthetic biology approach

    PubMed Central

    Adamala, Katarzyna; Anella, Fabrizio; Wieczorek, Rafal; Stano, Pasquale; Chiarabelli, Cristiano; Luisi, Pier Luigi

    2014-01-01

    In this mini-review we present some experimental approaches to the important issue in the origin of life, namely the origin of nucleic acids and proteins with specific and functional sequences. The formation of macromolecules on prebiotic Earth faces practical and conceptual difficulties. From the chemical viewpoint, macromolecules are formed by chemical pathways leading to the condensation of building blocks (amino acids, or nucleotides) in long-chain copolymers (proteins and nucleic acids, respectively). The second difficulty deals with a conceptual problem, namely with the emergence of specific sequences among a vast array of possible ones, the huge “sequence space”, leading to the question “why these macromolecules, and not the others?” We have recently addressed these questions by using a chemical synthetic biology approach. In particular, we have tested the catalytic activity of small peptides, like Ser-His, with respect to peptide- and nucleotides-condensation, as a realistic model of primitive organocatalysis. We have also set up a strategy for exploring the sequence space of random proteins and RNAs (the so-called “never born biopolymer” project) with respect to the production of folded structures. Being still far from solved, the main aspects of these “open questions” are discussed here, by commenting on recent results obtained in our groups and by providing a unifying view on the problem and possible solutions. In particular, we propose a general scenario for macromolecule formation via fragment-condensation, as a scheme for the emergence of specific sequences based on molecular growth and selection. PMID:24757502

  20. Genetic data suggest a natural prehuman origin of open habitats in northern Madagascar and question the deforestation narrative in this region.

    PubMed

    Quéméré, Erwan; Amelot, Xavier; Pierson, Julie; Crouau-Roy, Brigitte; Chikhi, Lounès

    2012-08-01

    The impact of climate change and anthropogenic deforestation on biodiversity is of growing concern worldwide. Disentangling how past anthropogenic and natural factors contributed to current biome distribution is thus a crucial issue to understand their complex interactions on wider time scales and to improve predictions and conservation strategies. This is particularly important in biodiversity hotspots, such as Madagascar, dominated by large open habitats whose origins are increasingly debated. Although a dominant narrative argues that Madagascar was originally entirely covered by woodlands, which were destroyed by humans, a number of recent studies have suggested that past climatic fluctuations played a major role in shaping current biome distributions well before humans arrived. Here, we address the question of the origin of open habitats in the Daraina region in northern Madagascar, using a multiproxy approach combining population genetics modeling and remote-sensing analyses. We show that (i) contrary to most regions of Madagascar, the forest cover in Daraina remained remarkably stable over the past 60 y, and (ii) the golden-crowned sifaka (Propithecus tattersalli), a forest-dwelling lemur, underwent a strong population contraction before the arrival of the first humans, hence excluding an anthropogenic cause. Prehuman Holocene droughts may have led to a significant increase of grasslands and a reduction in the species' habitat. This contradicts the prevailing narrative that land cover changes are necessarily anthropogenic in Madagascar but does not preclude the later role played by humans in other regions in which recent lemur bottlenecks have been observed.

  1. Genetic data suggest a natural prehuman origin of open habitats in northern Madagascar and question the deforestation narrative in this region

    PubMed Central

    Quéméré, Erwan; Amelot, Xavier; Pierson, Julie; Crouau-Roy, Brigitte; Chikhi, Lounès

    2012-01-01

    The impact of climate change and anthropogenic deforestation on biodiversity is of growing concern worldwide. Disentangling how past anthropogenic and natural factors contributed to current biome distribution is thus a crucial issue to understand their complex interactions on wider time scales and to improve predictions and conservation strategies. This is particularly important in biodiversity hotspots, such as Madagascar, dominated by large open habitats whose origins are increasingly debated. Although a dominant narrative argues that Madagascar was originally entirely covered by woodlands, which were destroyed by humans, a number of recent studies have suggested that past climatic fluctuations played a major role in shaping current biome distributions well before humans arrived. Here, we address the question of the origin of open habitats in the Daraina region in northern Madagascar, using a multiproxy approach combining population genetics modeling and remote-sensing analyses. We show that (i) contrary to most regions of Madagascar, the forest cover in Daraina remained remarkably stable over the past 60 y, and (ii) the golden-crowned sifaka (Propithecus tattersalli), a forest-dwelling lemur, underwent a strong population contraction before the arrival of the first humans, hence excluding an anthropogenic cause. Prehuman Holocene droughts may have led to a significant increase of grasslands and a reduction in the species’ habitat. This contradicts the prevailing narrative that land cover changes are necessarily anthropogenic in Madagascar but does not preclude the later role played by humans in other regions in which recent lemur bottlenecks have been observed. PMID:22826244

  2. Origin of the Vredefort structure, South Africa: Impact model

    NASA Technical Reports Server (NTRS)

    Therriault, A. M.; Reid, A. M.; Reimold, W. U.

    1993-01-01

    A model is presented for the evolution of the Vredefort structure, based on reasoned constraints on the original size of the Vredefort structure from observational data and comparison with other terrestrial impact craters. The models for complex craters (ring and multi-ring basins) of Croft, Grieve, and co-workers, and Schultz and co-workers, were used to reconstruct the Vredefort impact event, using a final crater diameter of 300 km, as estimated by Therriault. The sequence of events (stages 2-5) is illustrated diagramatically. The stages are: initial penetration, excavation and compression, dynamic rebound and uplift, maximum radial growth and collapse, and final crater form.

  3. The Origin and Impact History of Lunar Meteorite Yamato 86032

    NASA Technical Reports Server (NTRS)

    Yamaguchi, A.; Takeda, H.; Nyquist, L. E.; Bogard, D. D.; Ebihara, M.; Karouji, Y.

    2004-01-01

    Yamato (Y) 86032 is a feldspathic lunar highland breccia having some characteristics of regolith breccia. The absence of KREEP components in the matrix in Y86032 indicates that these meteorites came from a long distance from Mare Imbrium, perhaps from the far-side of the moon. One ferroan anorthosite (FAN) clast in Y86032 has a very old Ar-Ar age of approximately 4.35-4.4 Ga. The negative Nd of this clast may suggest a direct link with the primordial magma ocean. The facts indicate that Y86032 contains components derived from a protolith of the original lunar crust. Detailed petrologic characterization of each component in this breccia is essential to understand the early impact history and origin of the lunar highland crust. We made a large slab (5.2 x 3.6 cm x 3-5 mm) of Y86032 to better understand the relationship of various lithologies and their petrologic origin.

  4. Origin of orbital debris impacts on LDEF's trailing surfaces

    NASA Technical Reports Server (NTRS)

    Kessler, Donald J.

    1993-01-01

    A model was developed to determine the origin of orbital impacts measured on the training surfaces of LDEF. The model calculates the expected debris impact crater distribution around LDEF as a function of debris orbital parameters. The results show that only highly elliptical, low inclination orbits could be responsible for these impacts. The most common objects left in this type of orbit are orbital transfer stages used by the U.S. and ESA to place payloads into geosynchronous orbit. Objects in this type of orbit are difficult to catalog by the U.S. Space Command; consequently there are independent reasons to believe that the catalog does not adequately represent this population. This analysis concludes that the relative number of cataloged objects with highly elliptical, low inclination orbits must be increased by a factor of 20 to be consistent with the LDEF data.

  5. The origin and emergence of life under impact bombardment.

    PubMed

    Cockell, Charles S

    2006-10-29

    Craters formed by asteroids and comets offer a number of possibilities as sites for prebiotic chemistry, and they invite a literal application of Darwin's 'warm little pond'. Some of these attributes, such as prolonged circulation of heated water, are found in deep-ocean hydrothermal vent systems, previously proposed as sites for prebiotic chemistry. However, impact craters host important characteristics in a single location, which include the formation of diverse metal sulphides, clays and zeolites as secondary hydrothermal minerals (which can act as templates or catalysts for prebiotic syntheses), fracturing of rock during impact (creating a large surface area for reactions), the delivery of iron in the case of the impact of iron-containing meteorites (which might itself act as a substrate for prebiotic reactions), diverse impact energies resulting in different rates of hydrothermal cooling and thus organic syntheses, and the indiscriminate nature of impacts into every available lithology-generating large numbers of 'experiments' in the origin of life. Following the evolution of life, craters provide cryptoendolithic and chasmoendolithic habitats, particularly in non-sedimentary lithologies, where limited pore space would otherwise restrict colonization. In impact melt sheets, shattered, mixed rocks ultimately provided diverse geochemical gradients, which in present-day craters support the growth of microbial communities. PMID:17008223

  6. The origin and emergence of life under impact bombardment.

    PubMed

    Cockell, Charles S

    2006-10-29

    Craters formed by asteroids and comets offer a number of possibilities as sites for prebiotic chemistry, and they invite a literal application of Darwin's 'warm little pond'. Some of these attributes, such as prolonged circulation of heated water, are found in deep-ocean hydrothermal vent systems, previously proposed as sites for prebiotic chemistry. However, impact craters host important characteristics in a single location, which include the formation of diverse metal sulphides, clays and zeolites as secondary hydrothermal minerals (which can act as templates or catalysts for prebiotic syntheses), fracturing of rock during impact (creating a large surface area for reactions), the delivery of iron in the case of the impact of iron-containing meteorites (which might itself act as a substrate for prebiotic reactions), diverse impact energies resulting in different rates of hydrothermal cooling and thus organic syntheses, and the indiscriminate nature of impacts into every available lithology-generating large numbers of 'experiments' in the origin of life. Following the evolution of life, craters provide cryptoendolithic and chasmoendolithic habitats, particularly in non-sedimentary lithologies, where limited pore space would otherwise restrict colonization. In impact melt sheets, shattered, mixed rocks ultimately provided diverse geochemical gradients, which in present-day craters support the growth of microbial communities.

  7. The origin and emergence of life under impact bombardment

    PubMed Central

    Cockell, Charles S

    2006-01-01

    Craters formed by asteroids and comets offer a number of possibilities as sites for prebiotic chemistry, and they invite a literal application of Darwin's ‘warm little pond’. Some of these attributes, such as prolonged circulation of heated water, are found in deep-ocean hydrothermal vent systems, previously proposed as sites for prebiotic chemistry. However, impact craters host important characteristics in a single location, which include the formation of diverse metal sulphides, clays and zeolites as secondary hydrothermal minerals (which can act as templates or catalysts for prebiotic syntheses), fracturing of rock during impact (creating a large surface area for reactions), the delivery of iron in the case of the impact of iron-containing meteorites (which might itself act as a substrate for prebiotic reactions), diverse impact energies resulting in different rates of hydrothermal cooling and thus organic syntheses, and the indiscriminate nature of impacts into every available lithology—generating large numbers of ‘experiments’ in the origin of life. Following the evolution of life, craters provide cryptoendolithic and chasmoendolithic habitats, particularly in non-sedimentary lithologies, where limited pore space would otherwise restrict colonization. In impact melt sheets, shattered, mixed rocks ultimately provided diverse geochemical gradients, which in present-day craters support the growth of microbial communities. PMID:17008223

  8. ON A GIANT IMPACT ORIGIN OF CHARON, NIX, AND HYDRA

    SciTech Connect

    Canup, Robin M.

    2011-02-15

    It is generally believed that Charon was formed as a result of a large, grazing collision with Pluto that supplied the Pluto-Charon system with its high angular momentum. It has also been proposed that Pluto's small outer moons, Nix and Hydra, formed from debris from the Charon-forming impact, although the viability of this scenario remains unclear. Here I use smooth particle hydrodynamics impact simulations to show that it is possible to simultaneously form an intact Charon and an accompanying debris disk from a single impact. The successful cases involve colliding objects that are partially differentiated prior to impact, having thin outer ice mantles overlying a uniform composition rock-ice core. The composition of the resulting debris disks varies from a mixture of rock and ice (similar to the bulk composition of Pluto and Charon) to a pure ice disk. If Nix and Hydra were formed from such an impact-generated disk, their densities should be less than or similar to that of Charon and Pluto, and the small moons could be composed entirely of ice. If they were instead formed from captured material, a mixed rock-ice composition and densities similar to that of Charon and Pluto would be expected. Improved constraints on the properties of Nix and Hydra through occultations and/or the New Horizons encounter may thus help to distinguish between these two modes of origin, particularly if the small moons are found to have ice-like densities.

  9. Rotavirus vaccines in developing countries: the potential impact, implementation challenges, and remaining questions.

    PubMed

    Cherian, Thomas; Wang, Susan; Mantel, Carsten

    2012-04-27

    Diarrhoeal disease is one of the commonest causes of death in children, especially in developing countries in Africa and Asia. Rotavirus has been consistently identified as the commonest pathogen associated with severe diarrhoea. Hence, the availability of vaccines against this organism provides the opportunity to reduce child mortality. Data from efficacy trials in developing countries in Africa and Asia showed that the vaccine efficacy was lower than that observed in other countries. Nevertheless, the vaccines are expected to be of significant benefit in high mortality countries in these regions. While the reports published in this supplement add to our understanding about the performance of these vaccines in developing countries in these regions, questions remain over the overall impact of these vaccines when used in national programmes of developing countries in Africa and Asia, the optimal vaccination schedules and the impact of age restrictions for vaccine use on immunization coverage. Additional research is required to improve understanding on the performance of these vaccines in developing countries in Africa and Asia and measures that may improve performance. Data that will assist in the definition of the optimal immunization schedule and possibly allow relaxation of the age restrictions for vaccine use may help in enhancing the impact of the vaccines in these countries. Finally, disease surveillance and studies are required to document the impact of vaccination and monitor changes in disease epidemiology.

  10. Layered tektites - A multiple impact origin for the Australasian tektites

    NASA Astrophysics Data System (ADS)

    Wasson, J. T.

    1991-02-01

    The mechanisms proposed for the origin of tektites from the Australasian field are examined using neutron activation data for twenty layered tektites and six splash tektites of known and widely separated sites of a field greater than 1140 km in length. Evidence is presented indicating that the layered tektites formed as sheets or pools of melt. It is argued that their distribution across a field greater than 1140 km in length is inconsistent with their formation in a single crater, and that many impact craters are required to account for their distribution across such a large field.

  11. On an impact origin of Phobos-Deimos

    NASA Astrophysics Data System (ADS)

    Canup, Robin M.; Salmon, Julien

    2014-11-01

    Phobos and Deimos are the only example of terrestrial satellites other than our Moon, and their origin could provide constraints on Mars’ accretion. These tiny moons are also potential targets for robotic and manned exploration. Remarkably little is known about how Phobos and Deimos formed. A frequently cited idea is that the moons were carbonaceous asteroids captured intact into Mars orbit. However, intact capture appears inconsistent with their nearly circular orbits, which instead imply formation from a disk (e.g., Burns 1992; Peale 2007; Rosenblatt 2011). A natural way to form a disk is through a large, oblique impact. The difference in formation timescales for Mars 1 to 10 Myr; Nimmo & Kleine 1007) vs. the Earth 50 to 100 Myr; Touboul et al. 2007) suggests that Mars did not experience the protracted phase of giant impacts that Earth did. However, Mars’ rotation rate implies that it experienced at least one large impact at the end of its accretion by an object containing a few percent of Mars’ mass (e.g., Dones & Tremaine 1993). While an impact origin of Phobos-Deimos has been proposed (Craddock 2011), its viability has not been assessed with direct impact simulations.We have performed an initial series of such simulations, and these suggest that an impact consistent with Mars’ day produces a disk with orders-of-magnitude more mass than in Phobos and Deimos. A key distinction from an impact-generated protolunar disk is that at Mars, tidal interaction with the planet causes most moons to spiral inward toward the planet and be lost. For a disk that is initially entirely within Mars’ Roche limit (located at about 3 Mars radii), all moons may well be lost (Rosenblatt & Charnoz 2012). However we find initial disks that are more radially extended, with outer edges comparable to the inferred formation distances of Phobos and Deimos (between about 5.5 and 7 Mars radii). In this case, Phobos and Deimos could accrete from the outer disk and survive, while their

  12. Towards answering the "so what" question in marine renewables environmental impact assessment.

    NASA Astrophysics Data System (ADS)

    Degraer, Steven; Birchenough, Silvana N. R.; Braeckman, Ulrike; Coolen, Joop W. P.; Dannheim, Jennifer; De Mesel, Ilse; Grégoire, Marilaure; Kerckhof, Francis; Lacroix, Geneviève; Lindeboom, Han; Moens, Tom; Soetaert, Karline; Vanaverbeke, Jan; Van Hoey, Gert

    2016-04-01

    Marine renewable energy (MRE) projects are increasingly occupying the European North-Atlantic coasts and this is clearly observed in the North Sea. Given the expected impacts on the marine environment, each individual project is accompanied by a legally mandatory, environmental monitoring programme. These programmes are focused on the resultant effects on ecosystem component structure (e.g. species composition, numbers and densities) of single industrial projects. To date, there is a tendency to further narrow down to only a selection of ecosystem components (e.g. marine mammals and birds). While a wide knowledge-based understanding of structural impacts on (a selection of) ecosystem components exists, this evidence is largely lacking when undertaking impact assessments at the ecosystem functioning level (e.g. trophic interactions, dispersal and nutrient cycling). This critical knowledge gap compromises a scientifically-underpinned answer to the "so what" question of environmental impacts, i.e. whether the observed impacts are considered to be good or bad, or acceptable or unacceptable. The importance of ecosystem functioning is further acknowledged in the descriptors 4 and 6 of the Marine Strategy Framework Directive (EU MSFD) and is at the heart of a sustainable use and management of our marine resources. There hence is a fundamental need to focus on ecosystem functioning at the spatial scales at which marine ecosystems function when assessing MRE impacts. Here, we make a plea for an increased investment in a large (spatial) scale impact assessment of MRE projects focused on ecosystem functioning. This presentation will cover a selection of examples from North Sea MRE monitoring programmes, where the current knowledge has limited conclusions on the "so what" question. We will demonstrate how an ecosystem functioning-focused approach at an appropriate spatial scale could advance our current understanding, whilst assessing these issues. These examples will cover

  13. Origin of small pits in martian impact craters

    NASA Astrophysics Data System (ADS)

    Boyce, Joseph M.; Wilson, Lionel; Mouginis-Mark, Peter J.; Hamilton, Christopher W.; Tornabene, Livio L.

    2012-09-01

    We propose a numerical model for the formation of the closely-spaced pits found in the thin, ejecta-related deposits superposed on the floors, interior terrace blocks, and near-rim ejecta blankets of well-preserved martian impact craters. Our model predicts the explosive degassing of water from this pitted material, which is assumed to originally be water-bearing, impact melt-rich breccia at the time of deposition. This process is analogous to what occurred in the fall-out suevite deposits at the Ries impact structure in Germany. At Ries, impact heating of water-bearing target material resulted in the rapid degassing of its water and other volatiles. The martian environment plays an important role in enhancing the effects of this degassing by increasing the flow-speed of the escaping gas. The high flow-rate of gas through particulate materials, such as suevite, tends to quickly form segregation channels or vent pipes, similar to those found in the Ries deposits. These pipes act as conduits for the efficient high-speed escape of the gas and small clasts that it entrains. Escaping gas and entrained clasts abraded and eroded the conduit walls, flaring them to form pits above a network of pipes.

  14. An impact origin of the Earth-Moon system

    NASA Astrophysics Data System (ADS)

    Canup, R. M.; Asphaug, E.

    2001-12-01

    In the leading hypothesis for lunar origin, the Moon forms from debris ejected as a result of the collision of a roughly Mars-sized impactor with early Earth (Hartmann & Davis 1975; Cameron & Ward 1976). The likelihood of giant impact events has been substantiated by over a decade of planetary accretion simulations (e.g., Wetherill 1985, 1992; Agnor et al. 1999; Chambers 2001). The most recent simulations predict a median accretion time of 50 million years for an Earth analogue to reach 90% of its final mass (Chambers 2001), in good agreement with lunar and terrestrial formation times derived from Hf-W systematics (e.g., review by Halliday et al. 2000). Simulations of potential lunar forming impacts using a method known as smooth particle hydrodynamics, or SPH, can now achieve resolutions sufficient to study the production of bound debris necessary to yield the Moon. A wide variety of works have found that off-center, low-velocity collisions yield material in bound orbit from which a satellite may then accumulate. However, identifying impacts capable of producing the Earth-Moon system has proven difficult (Cameron 1997, 2000, 2001; Cameron & Canup 1998, Canup et al. 2001). Previous works (Cameron 1997, 2000, 2001) identified only two types of impacts capable of producing the Moon. The first involved an impact by an object with about 3 times the mass of Mars, and about twice the angular momentum of the Earth-Moon system; the second involved an the impact of an object with about twice the mass of Mars with an Earth that was only about half formed. Both scenarios are more restrictive and problematic than that originally envisioned, since they require that the Earth-Moon system's mass or angular momentum be significantly modified after the Moon-forming event by either multiple large impacts, or selective subsequent accretion of material onto only the Earth and not the Moon. Recent scaling trends identified in the SPH simulation results (Canup et al. 2001) implied that

  15. The Impact of Asking Intention or Self-Prediction Questions on Subsequent Behavior

    PubMed Central

    Wood, Chantelle; Conner, Mark; Miles, Eleanor; Sandberg, Tracy; Taylor, Natalie; Godin, Gaston; Sheeran, Paschal

    2015-01-01

    The current meta-analysis estimated the magnitude of the impact of asking intention and self-prediction questions on rates of subsequent behavior, and examined mediators and moderators of this question–behavior effect (QBE). Random-effects meta-analysis on 116 published tests of the effect indicated that intention/prediction questions have a small positive effect on behavior (d+ = 0.24). Little support was observed for attitude accessibility, cognitive dissonance, behavioral simulation, or processing fluency explanations of the QBE. Multivariate analyses indicated significant effects of social desirability of behavior/behavior domain (larger effects for more desirable and less risky behaviors), difficulty of behavior (larger effects for easy-to-perform behaviors), and sample type (larger effects among student samples). Although this review controls for co-occurrence of moderators in multivariate analyses, future primary research should systematically vary moderators in fully factorial designs. Further primary research is also needed to unravel the mechanisms underlying different variants of the QBE. PMID:26162771

  16. Impact origin of the Newporte structure, Williston basin, North Dakota

    SciTech Connect

    Forsman, N.F.; Gerlach, T.R.; Anderson, N.L.

    1996-05-01

    The Newporte field is located just south of the United States-Canada border in Renville County, North Dakota, in the north-central portion of the Williston basin. Integration of seismic, well-log, and core data supports the interpretation of an impact origin for the Newporte structure. The structure involves both Precambrian basement and lower Paleozoic sedimentary units. Oil and gas production began in 1977 from brecciated basement rocks along the rim of the 3.2-km-diameter circular structure. Both well logs and seismic data were used to determine thickness changes of sedimentary units overlying the structure. Resulting isopach maps reveal a circular, bowl-shaped feature with a recognizable rim. Microscopic shock metamorphic features in quartz and feldspar are visible in basement clasts that form a mixed breccia with Cambrian Deadwood sandstone within the western rim of the structure. A Late Cambrian-Early Ordovician age is suggested for the structure because of the presence of flatlying Deadwood sandstone overlying mixed basement/sandstone breccia along portions of the rim. Identification of the Newporte structure as an impact crater adds to the growing base of evidence revealing the relevance of impact craters to petroleum exploration.

  17. Testing and Resilience of the Impact Origin of the Moon

    NASA Technical Reports Server (NTRS)

    Righter, K.; Canup, R. M.

    2016-01-01

    The leading hypothesis for the origin of the Moon is the giant impact model, which grew out of the post-Apollo science community. The hypothesis was able to explain the high E-M system angular momentum, the small lunar core, and consistent with the idea that the early Moon melted substantially. The standard hypothesis requires that the Moon be made entirely from the impactor, strangely at odds with the nearly identical oxygen isotopic composition of the Earth and Moon, compositions that might be expected to be different if Moon came from a distinct impactor. Subsequent geochemical research has highlighted the similarity of both geochemical and isotopic composition of the Earth and Moon, and measured small but significant amounts of volatiles in lunar glassy materials, both of which are seemingly at odds with the standard giant impact model. Here we focus on key geochemical measurements and spacecraft observations that have prompted a healthy re-evaluation of the giant impact model, provide an overview of physical models that are either newly proposed or slightly revised from previous ideas, to explain the new datasets.

  18. The origins and impact of primate segmental duplications

    PubMed Central

    Marques-Bonet, Tomas; Girirajan, Santhosh; Eichler, Evan E.

    2009-01-01

    Duplicated sequences are substrates for the emergence of new genes and are an important source of genetic instability associated with rare and common diseases. Analyses of primate genomes have shown an increase in the proportion of interspersed segmental duplications (SDs) within the genomes of humans and great apes. This contrasts with other mammalian genomes that seem to have their recently duplicated sequences organized in a tandem configuration. In this review, we focus on the mechanistic origin and impact of this difference with respect to evolution, genetic diversity and primate phenotype. Although many genomes will be sequenced in the future, resolution of this aspect of genomic architecture still requires high quality sequences and detailed analyses. PMID:19796838

  19. Early Archean Spherule Beds-Confirmation of Impact Origin

    NASA Technical Reports Server (NTRS)

    Shukolyukov, A.; Kyte, F. T.; Lugmair, G. W.; Lowe, D. R.; Byerly, G. R.

    2000-01-01

    The oldest record of major impact events on Earth may be a number of early Archean (3.5 to 3.2 Ga) spherule beds that have been identified in the Barberton Greenstone Belt, South Africa. Several field, petrographic, and geochemical criteria distinguish these beds from typical volcanic and clastic sediments. These criteria include the wide geographic distribution of two beds in a variety of depositional environments, the presence of relict quench textures, absence of juvenile volcaniclastic debris within the beds, and extreme enrichment of Ir and other platinum group elements (PGE) as compared to surrounding sediments. Some researchers, however, argued for a terrestrial origin for spherule bed formation, possibly related to volcanism and gold mineralization.

  20. Framing the willingness-to-pay question: impact on response patterns and mean willingness to pay.

    PubMed

    Gyrd-Hansen, Dorte; Jensen, Mette Lundsby; Kjaer, Trine

    2014-05-01

    In this study, respondents were randomly allocated to three variants of the payment card format and an open-ended format in order to test for convergent validity. The aim was to test whether preferences (as measured by willingness to pay additional tax) would be affected by framing the willingness-to-pay question differently. Results demonstrated that valuations were highly sensitive to whether respondents were asked to express their maximum willingness to pay per month or per year. Another important finding is that the introduction of a binary response filter prior to the payment card follow-up tends to eliminate the positive aspects of introducing a payment card and produces response patterns that are much in line with those of the open-ended contingent valuation format. However, although a filter will impact on the distribution of willingness-to-pay bids and on the rate of zero and protest bids, the overall impact on the welfare estimate is minor. The outcomes of this study indicate that valuations in the stated preference literature may be, at least in part, a function of the instrument designed to obtain the valuations. PMID:23696155

  1. Does measuring body weight impact subsequent response to eating behavior questions?

    PubMed Central

    Pacanowski, Carly R.; Sobal, Jeffery; Levitsky, David A.; Sherwood, Nancy E.; Keeler, Chelsey L.; Miller, April M.; Acosta, Ashley R.; Hansen, Natalie; Wang, Peter L.; Guilbert, Sarah R.; Paroly, Arianne L.; Commesso, Michael; Vermeylen, Francoise M.

    2016-01-01

    If being weighed impacts perceptions of eating behavior, it is important that the order of questionnaires and weighing be considered in research and practice. A quasi-experimental study was performed to examine whether being weighed immediately prior to completing a questionnaire affects responses to eating behavior questions. It was hypothesized that being weighed would serve as a priming stimulus and increase measures of dietary restraint, disinhibition, and hunger. Trained researchers collected a sample of volunteers (n = 355) in 8 locations in the United States on two Saturdays in the summer of 2011. Half of the participants were weighed immediately prior to completing the Three Factor Eating Questionnaire (TFEQ), with the remaining half weighed immediately after TFEQ completion. A priori hypotheses were not supported despite replicating known relationships between weight, dietary restraint and disinhibition. Results indicated that being weighed first produced a difference in differences on disinhibition scores between low restraint score (95% CI = 4.65–6.02) and high restraint score (95% CI = 6.11–7.57) compared to being weighed after questionnaire completion (p = 0.003). However, this relationship was not significant when modeling restraint as a continuous variable, questioning the use of dichotomization. Being weighed is unlikely to be a strong enough prime to significantly change scores on eating behavior questionnaires for everyone, but may allow differences in restraint status to become more evident. Researchers assessing dietary restraint should be wary of the possibility of producing different results when treating restraint as continuous or dichotomous, which could lead to different interpretations. PMID:25751019

  2. A One-Day Dental Faculty Workshop in Writing Multiple-Choice Questions: An Impact Evaluation.

    PubMed

    AlFaris, Eiad; Naeem, Naghma; Irfan, Farhana; Qureshi, Riaz; Saad, Hussain; Al Sadhan, Ra'ed; Abdulghani, Hamza Mohammad; Van der Vleuten, Cees

    2015-11-01

    Long training workshops on the writing of exam questions have been shown to be effective; however, the effectiveness of short workshops needs to be demonstrated. The aim of this study was to evaluate the impact of a one-day, seven-hour faculty development workshop at the College of Dentistry, King Saud University, Saudi Arabia, on the quality of multiple-choice questions (MCQs). Kirkpatrick's four-level evaluation model was used. Participants' satisfaction (Kirkpatrick's Level 1) was evaluated with a post-workshop questionnaire. A quasi-experimental, randomized separate sample, pretest-posttest design was used to assess the learning effect (Kirkpatrick's Level 2). To evaluate transfer of learning to practice (Kirkpatrick's Level 3), MCQs created by ten faculty members as a result of the training were assessed. To assess Kirkpatrick's Level 4 regarding institutional change, interviews with three key leaders of the school were conducted, coded, and analyzed. A total of 72 course directors were invited to and attended some part of the workshop; all 52 who attended the entire workshop completed the satisfaction form; and 22 of the 36 participants in the experimental group completed the posttest. The results showed that all 52 participants were highly satisfied with the workshop, and significant positive changes were found in the faculty members' knowledge and the quality of their MCQs with effect sizes of 0.7 and 0.28, respectively. At the institutional level, the interviews demonstrated positive structural changes in the school's assessment system. Overall, this one-day item-writing faculty workshop resulted in positive changes at all four of Kirkpatrick's levels; these effects suggest that even a short training session can improve a dental school's assessment of its students.

  3. Impact of Question-Answering Tasks on Search Processes and Reading Comprehension

    ERIC Educational Resources Information Center

    Cerdan, Raquel; Vidal-Abarca, Eduardo; Martinez, Tomas; Gilabert, Ramiro; Gil, Laura

    2009-01-01

    This study examined the effect of (a) high- and low-level questions and (b) reading the text before the questions asked on performance, delayed text recall, and deep text comprehension, as well as on specific text-inspection patterns. Participants were 37 undergraduate students who answered either high- or low-level questions using the software…

  4. An Impact Origin for Surface Minerals on Ceres

    NASA Astrophysics Data System (ADS)

    Zolotov, M. Y.

    2013-12-01

    The dwarf planet Ceres is the largest body in the main asteroid belt with a hydrated dark rocky surface and an uncertain internal structure [1,2]. Spectra of Ceres in the near- and mid-infrared ranges show that surface materials may not contain abundant serpentine, saponite, sulfates, olivine, pyroxenes, and organic matter [2,3], which are common in carbonaceous chondrites. However, brucite, Mg carbonates, cronstedtite, and magnetite could be abundant and indicate aqueous processes [2,3]. The formation of abundant brucite, carbonates, and cronstedtite requires open-system low-temperature conditions characterized by elevated water/rock ratios and low fugacities of hydrogen and carbon dioxide. The observed mineralogy is more consistent with a near-surface origin than with a formation within Ceres or on planetesimals. The instability of aqueous solutions at the surface of Ceres implies mineral deposition during transient events of fluidal activity. But a warming of near-surface rocks by thermal processes in the interior requires dehydration of rocks, which is not consistent with the low density of Ceres. The lack of low-solubility sulfates in surface materials does not indicate percolation of interior fluids. Carbonate-bearing fluids may not percolate to the cold surface, especially if Ceres had undergone water-rock differentiation [1,4]. The lack of serpentine in surface materials does not indicate a formation of brucite through aqueous alteration of olivine-rich rocks. Though, the observed minerals could form in impact collisions of ice-rich targets and/or impactors. OH-bearing phases may condense from water-rich impact plumes [5]. Brucite and Mg carbonates could form through hydrolysis and carbonation of condensed MgO formed through evaporation of silicates. Apparently abundant carbonates may indicate an ample oxidation of organics. Ferric iron in magnetite and cronstedtite agrees with water-rich and oxidizing impact settings [5]. Turbulent and disequilibrium

  5. Origin of tektites: an alternative to terrestrial impact theory.

    PubMed

    Izokh, E P

    1996-01-01

    The Terrestrial Impact Theory (TIT) has won a complete victory over O'Keefe's lunar volcanic theory, but only because the Moon appears to be the wrong place for tektites. Indeed, the TIT ignores strong evidence of their volcanic origin--far from the Moon. The Extraterrestrial Volcanic Comet Theory proposes an alternative to both of these theories. Major arguments for an extraterrestrial tektite source are paradoxical: a great time difference between tektite formation and their arrival on Earth, and also forms, plastic deformations, ice collision marks, vacuum voids, etc. indicating specific conditions of tektite formation such as low gravitational field, lack of atmosphere, interaction of hot plastic tektites with ice, etc. Major evidence of volcanic origin includes: close analogy between shaped tektites and small volcanic bombs, and between layered tektites and lava or tuff-lava flows or huge bombs; analogy between flanged tektites and volcanic bombs ablated by gasjets: long-time, multistage formation of some tektites that corresponds to wide variations in their radiometric ages; well-ordered long compositional trends (series) typical of magmatic differentiation; different compositional tektite families (subseries) comparable to different stages (phases) of the volcanic process. Thus, different types of volcanic eruptions under extraterrestrial conditions could be reconstructed based on tektite properties. It is presumed that tektites were transported to the Earth by specific eruptive comets, i.e. in the form of ice-tektite agglomerates launched into space by volcanic explosion. Major arguments favouring comets include: ice collision marks and imprints as mentioned above; linear band-like sculpture of the Australasian strewn field as evidence of comet fragmentation and slope or skipping trajectory of separate fragments; compact coincidence of the Zhamanshin impact crater with small tektite strewn field as evidence of steep trajectory of separate comet fragments

  6. Origin of tektites: an alternative to terrestrial impact theory.

    PubMed

    Izokh, E P

    1996-01-01

    The Terrestrial Impact Theory (TIT) has won a complete victory over O'Keefe's lunar volcanic theory, but only because the Moon appears to be the wrong place for tektites. Indeed, the TIT ignores strong evidence of their volcanic origin--far from the Moon. The Extraterrestrial Volcanic Comet Theory proposes an alternative to both of these theories. Major arguments for an extraterrestrial tektite source are paradoxical: a great time difference between tektite formation and their arrival on Earth, and also forms, plastic deformations, ice collision marks, vacuum voids, etc. indicating specific conditions of tektite formation such as low gravitational field, lack of atmosphere, interaction of hot plastic tektites with ice, etc. Major evidence of volcanic origin includes: close analogy between shaped tektites and small volcanic bombs, and between layered tektites and lava or tuff-lava flows or huge bombs; analogy between flanged tektites and volcanic bombs ablated by gasjets: long-time, multistage formation of some tektites that corresponds to wide variations in their radiometric ages; well-ordered long compositional trends (series) typical of magmatic differentiation; different compositional tektite families (subseries) comparable to different stages (phases) of the volcanic process. Thus, different types of volcanic eruptions under extraterrestrial conditions could be reconstructed based on tektite properties. It is presumed that tektites were transported to the Earth by specific eruptive comets, i.e. in the form of ice-tektite agglomerates launched into space by volcanic explosion. Major arguments favouring comets include: ice collision marks and imprints as mentioned above; linear band-like sculpture of the Australasian strewn field as evidence of comet fragmentation and slope or skipping trajectory of separate fragments; compact coincidence of the Zhamanshin impact crater with small tektite strewn field as evidence of steep trajectory of separate comet fragments

  7. The Origin Of Phobos And Deimos By A Giant Impact

    NASA Astrophysics Data System (ADS)

    Craddock, R. A.

    2011-10-01

    Despite many efforts an adequate theory describing the origin of Phobos and Deimos has not been realized. In recent years a number of separate observations suggest the possibility that the Martian satellites may have been the result of giant impact [1]. Similar to the Earth-Moon system, Mars has too much angular momentum. A planetesimal with 0.02 Mars masses must have collided with that planet early in its history in order for Mars to spin at its current rate [2]. Although subject to considerable error, current crater scaling laws and an analysis of the largest known impact basins on the Martian surface suggest that this planetesimal could have formed either the proposed 10,600 by 8,500-kmdiameter Borealis basin, the 4,970-km-diameter Elysium basin, the 4,500-km-diameter Daedalia basin or, alternatively, some other basin that is no longer identifiable. It is also probable that this object impacted Mars at a velocity great enough to vaporize rock (>7 km/s), which is necessary to place large amounts of material into orbit. If material vaporized from the collision with the Mars-spinning planetesimal were placed into orbit, an accretion disk would have resulted. It is possible that as material condensed and dissipated beyond the Roche limit forming small, low-mass satellites due to gravity instabilities within the disk. Once the accretion disk dissipated, tidal forces and libration would have pulled these satellites back down toward the Martian surface. In this scenario, Phobos and Deimos would have been among the first two satellites to form, and Deimos the only satellite formed--and preserved-- beyond synchronous rotation. The low mass of Phobos and Deimos is explained by the possibility that they are composed of loosely aggregated material from the accretion disk, which also implies that they do not contain any volatile elements. Their orbital eccentricity and inclination, which are the most difficult parameters to explain easily with the various capture scenarios

  8. Questioning the Questions

    ERIC Educational Resources Information Center

    Tienken, Christopher H.; Goldberg, Stephanie; DiRocco, Dominic

    2010-01-01

    Historical accounts of questioning used in the education process trace back to Socrates. One of the best examples of his use of questioning is found in Plato's "The Republic." Socrates used a series of strategic questions to help his student Glaucon come to understand the concept of justice. Socrates purposefully posed a series of questions to…

  9. The Sirente crater, Italy: Impact versus mud volcano origins

    NASA Astrophysics Data System (ADS)

    Stoppa, Francesco

    2006-03-01

    The Sirente crater is a circular structure with a diameter of ˜80 m. The rim deposit is an inverse-graded, matrix-supported breccia. Sedimentological features of the rim deposit suggest that the crater is not related to an explosion or violent mechanical displacement. The structure and texture of the deposit exhibit a primary sedimentary character. The rim deposits do not contain artifacts and do not show evidence of reworking. A multistage formation is reconstructed for the rim growth and associated deposits. The geometry and sedimentology of the deposits indicate that they were produced by the extrusion and accumulation of mudflow deposits. The dominant ejection mechanism was low mud fountains and the transport medium was water. Petrographic and geochemical evidence does not indicate any physical or cryptic trace of an extraterrestrial body. The most realistic agent that explains the observed effects is a rapid local emission of mud and/or water. Geological processes capable of producing these features include piping sinkholes or, more probably, "caldera"-type mud volcanoes, which may result from underground water-table perturbation and/or decompression of deep CO2/hydrocarbon gas reservoirs due to tectonic deformation or faulting activity during a seismic event. In both cases, the name "crater" for this geological form may be maintained, but there is no compelling evidence for an impact origin. In this paper, the scientific literature on the Sirente crater is reconsidered in the light of new morphological, sedimentological, geochemical, and archaeological data. A new mechanism is proposed involving mud-fountaining.

  10. The Impact of Self-Questioning Strategy Use on the Text-Reader Assisted Comprehension of Students with Reading Disabilities

    ERIC Educational Resources Information Center

    Manset-Williamson, Genevieve; Dunn, Michael; Hinshaw, Rebecca; Nelson, Jason M.

    2008-01-01

    This study involved an examination of the impact of a self-questioning strategy on the text-reader assisted comprehension skills of six students in grades five through eight with reading disabilities (RD). The purpose of this study was to determine the degree older children with RD comprehend text-reader assisted text that is at or above their…

  11. Questioning the Questions

    ERIC Educational Resources Information Center

    Tienken, Christopher H.; Goldberg, Stephanie; DiRocco, Dominic

    2009-01-01

    Well-known historical accounts of questioning used in the education process trace back to Socrates. One of the best examples of his use of questioning is found in Plato's classic work "The Republic" (2003). Today, teachers still use questions as one way to help students develop productive thinking skills and to understand concepts and topics.…

  12. Positive vs. Negative: The Impact of Question Polarity in Voting Advice Applications

    PubMed Central

    Krouwel, André; van de Pol, Jasper; de Vreese, Claes

    2016-01-01

    Online Voting Advice Applications (VAAs) are survey-like instruments that help citizens to shape their political preferences and compare them with those of political parties. Especially in multi-party democracies, their increasing popularity indicates that VAAs play an important role in opinion formation for citizens, as well as in the public debate prior to elections. Hence, the objectivity and transparency of VAAs are crucial. In the design of VAAs, many choices have to be made. Extant research in survey methodology shows that the seemingly arbitrary choice to word questions positively (e.g., ‘The city council should allow cars into the city centre’) or negatively (‘The city council should ban cars from the city centre’) systematically affects the answers. This asymmetry in answers is in line with work on negativity bias in other areas of linguistics and psychology. Building on these findings, this study investigated whether question polarity also affects the answers to VAA statements. In a field experiment (N = 31,112) during the Dutch municipal elections we analysed the effects of polarity for 16 out of 30 VAA statements with a large variety of linguistic contrasts. Analyses show a significant effect of question wording for questions containing a wide range of implicit negations (such as ‘forbid’ vs. ‘allow’), as well as for questions with explicit negations (e.g., ‘not’). These effects of question polarity are found especially for VAA users with lower levels of political sophistication. As these citizens are an important target group for Voting Advice Applications, this stresses the need for VAA builders to be sensitive to wording choices when designing VAAs. This study is the first to show such consistent wording effects not only for political attitude questions with implicit negations in VAAs, but also for political questions containing explicit negations. PMID:27723776

  13. The impact of definition and question order on the prevalence of bullying victimization using student self-reports.

    PubMed

    Huang, Francis L; Cornell, Dewey G

    2015-12-01

    Accurate measurement is essential to determining the prevalence of bullying and evaluating the effectiveness of intervention efforts. The most common measurement approach is through anonymous self-report surveys, but previous studies have suggested that students do not adhere to standard definitions of bullying and may be influenced by the order of questions about types of victimization. In the current study, we have presented findings from 2 randomized experiments designed to determine (a) the impact of using or not using a definition of bullying and (b) asking about general versus specific types of bullying victimization and how the order of these questions affects victimization-prevalence rates. The study was conducted using a sample of 17,301 students attending 119 high schools. Findings indicate that the use of a definition had no impact on prevalence rates, but asking specific bullying-victimization questions (e.g., "I have been verbally bullied at school") prior to general bullying-victimization questions (e.g., "I have been bullied at school"), resulted in a 29-76% increase in victimization-prevalence rates. Results suggest that surveys that ask general-to-specific bullying-victimization questions, such as those found in national and international surveys, may be underreporting bullying victimization. PMID:25938336

  14. Unreviewed Disposal Question Evaluation: Impact of New Information since 2008 PA on Current Low-Level Solid Waste Operations

    SciTech Connect

    Flach, G.; Smith, F.; Hamm, L.; Butcher, T.

    2014-10-06

    Solid low-level waste disposal operations are controlled in part by an E-Area Low-Level Waste Facility (ELLWF) Performance Assessment (PA) that was completed by the Savannah River National Laboratory (SRNL) in 2008 (WSRC 2008). Since this baseline analysis, new information pertinent to disposal operations has been identified as a natural outcome of ongoing PA maintenance activities and continuous improvement in model simulation techniques (Flach 2013). An Unreviewed Disposal Question (UDQ) Screening (Attachment 1) has been initiated regarding the continued ability of the ELLWF to meet Department of Energy (DOE) Order 435.1 performance objectives in light of new PA items and data identified since completion of the original UDQ Evaluation (UDQE). The present UDQE assesses the ability of Solid Waste (SW) to meet performance objectives by estimating the influence of new information items on a recent sum-of-fractions (SOF) snapshot for each currently active E-Area low-level waste disposal unit. A final SOF, as impacted by this new information, is projected based on the assumptions that the current disposal limits, Waste Information Tracking System (WITS) administrative controls, and waste stream composition remain unchanged through disposal unit operational closure (Year 2025). Revision 1 of this UDQE addresses the following new PA items and data identified since completion of the original UDQE report in 2013: New Kd values for iodine, radium and uranium; Elimination of cellulose degradation product (CDP) factors; Updated radionuclide data; Changes in transport behavior of mobile radionuclides; Potential delay in interim closure beyond 2025; and Component-in-grout (CIG) plume interaction correction. Consideration of new information relative to the 2008 PA baseline generally indicates greater confidence that PA performance objectives will be met than indicated by current SOF metrics. For SLIT9, the previous prohibition of non-crushable containers in revision 0

  15. Impact of Repeated Questioning on Interviewers: Learning From a Forensic Interview Training Project.

    PubMed

    Duron, Jacquelynn F; Cheung, Monit

    2016-01-01

    Forensic interviewers have a difficult job with high risk for career burnout and secondary trauma. Few studies have addressed how new forensic interviewers or trainees experience repeated questioning and multiple interviews. This study simulated the process of training new forensic interviewers through the creation of two interview videos in which social work graduate students participated as actors portraying the roles of interviewer and child. These films served as instructional aids preparing graduate social work students for professional child welfare roles while promoting research-based approaches to interviewing children about sexual abuse allegations. Qualitative data from two cohorts of student actors were collected to analyze interviewers' perspectives on repeated questioning and interviews in child sexual abuse cases. Two themes were extracted from the subjects' experiences: "It is emotionally taxing" and "Navigating the interviewer role is unexpectedly complex." Exposure to repeated questions and multiple interviews affected the performance and confidence of the interviewers. PMID:27266533

  16. An investigation into the impact of question change on estimates of general health status and healthy life expectancy.

    PubMed

    Smith, Michael; White, Chris

    2009-01-01

    This article investigates the likely effects of incorporating the European Union Statistics on Income and Living Conditions (EU-SILC) general health question upon Office for National Statistics (ONS) estimates of general health and healthy life expectancy (HLE). The analysis indicates that while these estimates will undergo revision following the integration of the EU-SILC general health question, for the most part the underlying trend remains unaffected. Incorporation of the EU-SILC question in the reporting of UK health statistics will improve comparability with other EU member states, and provide a stronger indicator of functional health status. ONS will adopt the EU-SILC general health question exclusively from the reporting period 2006-08. However, to further clarify the implications of this transition, ONS will present two estimates of HLE based on the original and EU-SILC general health questions for the period 2005-07. This article has important implications for setting targets and monitoring progress in Public Sector Agreement Indicators for fitness for work beyond the state pension age and healthy ageing.

  17. Students' Questions and Discursive Interaction: Their Impact on Argumentation during Collaborative Group Discussions in Science

    ERIC Educational Resources Information Center

    Chin, Christine; Osborne, Jonathan

    2010-01-01

    This study investigated the potential of students' written and oral questions both as an epistemic probe and heuristic for initiating collaborative argumentation in science. Four classes of students, aged 12-14 years from two countries, were asked to discuss which of two graphs best represented the change in temperature as ice was heated to steam.…

  18. How to Improve Your Impact Factor: Questioning the Quantification of Academic Quality

    ERIC Educational Resources Information Center

    Smeyers, Paul; Burbules, Nicholas C.

    2011-01-01

    A broad-scale quantification of the measure of quality for scholarship is under way. This trend has fundamental implications for the future of academic publishing and employment. In this essay we want to raise questions about these burgeoning practices, particularly how they affect philosophy of education and similar sub-disciplines. First,…

  19. Implications of an impact origin for the martian hemispheric dichotomy.

    PubMed

    Nimmo, F; Hart, S D; Korycansky, D G; Agnor, C B

    2008-06-26

    The observation that one hemisphere of Mars is lower and has a thinner crust than the other (the 'martian hemispheric dichotomy') has been a puzzle for 30 years. The dichotomy may have arisen as a result of internal mechanisms such as convection. Alternatively, it may have been caused by one or several giant impacts, but quantitative tests of the impact hypothesis have not been published. Here we use a high-resolution, two-dimensional, axially symmetric hydrocode to model vertical impacts over a range of parameters appropriate to early Mars. We propose that the impact model, in addition to excavating a crustal cavity of the correct size, explains two other observations. First, crustal disruption at the impact antipode is probably responsible for the observed antipodal decline in magnetic field strength. Second, the impact-generated melt forming the northern lowlands crust is predicted to derive from a deep, depleted mantle source. This prediction is consistent with characteristics of martian shergottite meteorites and suggests a dichotomy formation time approximately 100 Myr after martian accretion, comparable to that of the Moon-forming impact on Earth.

  20. An impact origin for hydrated silicates on Mars: A synthesis

    NASA Astrophysics Data System (ADS)

    Tornabene, Livio L.; Osinski, Gordon R.; McEwen, Alfred S.; Wray, James J.; Craig, Michael A.; Sapers, Haley M.; Christensen, Philip R.

    2013-05-01

    Recent Mars-orbiting spectrometers continue to detect surface materials containing hydrated silicates, particularly clays and amorphous phases (e.g., silica glasses), concentrated within the heavily cratered Noachian highlands crust. This paper provides a review, summary, and synthesis of observations from terrestrial impact structures with current Martian data. It is suggested that numerous and frequent impacts into the volatile-rich silicate crust of Mars, through direct and indirect impact-generated mechanisms, represent a plausible hypothesis that can explain the widespread distribution of hydrated silicates in the surface and subsurface of the heavily cratered Noachian highlands crust largely independent of climate. In addition to impact-generated hydrothermal activity, devitrification, autometamorphism, and the voluminous production of impact "damaged" materials that are susceptible to alteration must be considered. When taken together, a drastically different early climate on Mars, in which water is stable at the surface for extended periods of time, cannot be ruled out; however, it is noted here that these additional impact mechanisms can operate and thereby extend the range of possible alteration settings to include climate conditions that may have been predominately colder and drier. Such a climate would not be dissimilar to the conditions of today, with the important exceptions of a higher geothermal gradient, and punctuated thermal disturbance to the cryosphere and hydrosphere from igneous activity and an exponentially higher impact flux.

  1. Satellite RNA pathogens of plants: impacts and origins-an RNA silencing perspective.

    PubMed

    Wang, Ming-Bo; Smith, Neil A

    2016-01-01

    Viral satellite RNAs (satRNAs) are among the smallest RNA pathogens in plants. They have little or no protein-coding capacity but can have a major impact on the host plants through trilateral interactions with helper viruses and host plants. Studies around the 1980s revealed much of what we know about satRNAs: they can affect helper virus accumulation, modulate helper virus-induced disease symptoms, and induce their own symptoms with the assistance of helper viruses which depend on specific nucleotide sequences of their genome and host species. The molecular basis of these satRNA-caused impacts and the origin of satRNAs have yet to be fully understood and revealed, but recent understanding of the antiviral RNA silencing pathways and advancement in RNA and DNA sequencing technologies have provided new avenues and opportunities to examine these unanswered questions. These RNA silencing-based studies have revealed the existence of cross silencing between some satRNAs and helper viruses, the downregulation of helper virus-encoded suppressor (VSR) of RNA silencing or inhibition/enhancement of VSR activity by satRNAs, the silencing of host-encoded genes by satRNA-derived small interfering RNA (siRNAs), and the presence of satRNA-like small RNAs in uninfected host plants. These findings have provided alternative RNA silencing-based models to explain the pathogenicity and origin of satRNAs. WIREs RNA 2016, 7:5-16. doi: 10.1002/wrna.1311 For further resources related to this article, please visit the WIREs website.

  2. Genes as a historical archive: on the applicability of genetic research to sociohistorical questions: the debate on the origins of Ashkenazi Jewry revisited.

    PubMed

    Kohler, Noa Sophie

    2014-01-01

    The origin of the Ashkenazi Jews has fascinated a growing number of geneticists in recent decades. Using genetic markers to answer questions of history is an approach that is at once tempting and precarious. Both genetics and history are highly specialized fields, and with an interdisciplinary approach, difficulties abound.This article briefly discusses this complex issue based on two studies, written by geneticists,which aimed at contributing to the research on the history of Ashkenazi Jewry.To date, geneticists who have tried to tackle historical questions by means of genetics and statistics have had difficulties with the dialectic methods of historiography, while historians have often misinterpreted the validity of the research results of the so-called "exact sciences." Only when both sides study and understand the other side's methodology can cooperation lead to usable and meaningful results. PMID:25345705

  3. Values in Translation: How Asking the Right Questions Can Move Translational Science Toward Greater Health Impact

    PubMed Central

    Kelley, Maureen; Edwards, Kelly; Starks, Helene; Fullerton, Stephanie M; James, Rosalina; Goering, Sara; Holland, Suzanne; Disis, Mary L; Burke, Wylie

    2012-01-01

    The speed and effectiveness of current approaches to research translation are widely viewed as disappointing given small gains in real population health outcomes despite huge investments in basic and translational science. We identify critical value questions—ethical, social, economic, and cultural—that arise at moments throughout the research pathway. By making these questions visible, and promoting discussion of them with diverse stakeholders, we can facilitate handoffs along the translational pathway and increase uptake of effective interventions. Who is involved with those discussions will determine which research projects, populations, and methods get prioritized. We argue that some upfront investment in community and interdisciplinary engagement, shaped by familiar questions in ethics, social justice, and cultural knowledge, can save time and resources in the long run because interventions and strategies will be aimed in the right direction, that is, toward health improvements for all. Clin Trans Sci 2012; Volume 5: 445–451 PMID:23253665

  4. Dahlia latent viroid: a recombinant new species of the family Pospiviroidae posing intriguing questions about its origin and classification.

    PubMed

    Verhoeven, Jacobus Th J; Meekes, Ellis T M; Roenhorst, Johanna W; Flores, Ricardo; Serra, Pedro

    2013-04-01

    A viroid-like RNA has been detected in two asymptomatic dahlia accessions by return and double PAGE. It appeared smaller than Chrysanthemum stunt viroid and Potato spindle tuber viroid, the two members of the genus Pospiviroid, family Pospiviroidae, reported in this ornamental previously. RT-PCR with primers designed for amplifying all pospiviroids produced no amplicons, but RT-PCR with random primers revealed a 342 nt RNA. The sequence of this RNA was confirmed with specific primers, which additionally revealed its presence in many dahlia cultivars. The RNA was named Dahlia latent viroid (DLVd) because it replicates autonomously, but symptomlessly, in dahlia and shares maximum sequence identity with other viroids of less than 56 %. Furthermore, DLVd displays characteristic features of the family Pospiviroidae: a predicted rod-like secondary structure of minimum free energy with a central conserved region (CCR), and the ability to form the metastable structures hairpins I and II. Its CCR is identical to that of Hop stunt viroid (HSVd, genus Hostuviroid). However, DLVd: (i) has the terminal conserved region present in members of the genus Pospiviroid, but absent in HSVd, and (ii) lacks the terminal conserved hairpin present in HSVd. Phylogenetic reconstructions indicate that HSVd and Pepper chat fruit viroid (genus Pospiviroid) are the closest relatives of DLVd, but DLVd differs from these viroids in its host range, restricted to dahlia so far. Therefore, while DLVd fulfils the criteria to be a novel species of the family Pospiviroidae, its recombinant origin makes assignment to the genera Pospiviroid or Hostuviroid problematic. PMID:23255620

  5. A question of origin: dioxin-like PCBs and their relevance in stock management of European eels.

    PubMed

    Freese, Marko; Sühring, Roxana; Pohlmann, Jan-Dag; Wolschke, Hendrik; Magath, Victoria; Ebinghaus, Ralf; Hanel, Reinhold

    2016-01-01

    The stock of European Eel (Anguilla anguilla L.) has reached an all-time low in 2011. Spawner quality of mature eels in terms of health status and fitness is considered one of the key elements for successful migration and reproduction. Dioxin-like Polychlorinated Biphenyls (dl-PCBs) are known persistent organic pollutants potentially affecting the reproductive capability and health status of eels throughout their entire lifetime. In this study, muscle tissue samples of 192 European eels of all continental life stages from 6 different water bodies and 13 sampling sites were analyzed for contamination with lipophilic dl-PCBs to investigate the potential relevance of the respective habitat in light of eel stock management. Results of this study reveal habitat-dependent and life history stage-related accumulation of targeted PCBs. Sum concentrations of targeted PCBs differed significantly between life stages and inter-habitat variability in dl-PCB levels and -profiles was observed. Among all investigated life stages, migrant silver eels were found to be the most suitable life history stage to represent their particular water system due to habitat dwell-time and their terminal contamination status. With reference to a possible negative impact of dl-PCBs on health and the reproductive capability of eels, it was hypothesized that those growing up in less polluted habitats have a better chance to produce healthy offspring than those growing up in highly polluted habitats. We suggest that the contamination status of water systems is fundamental for the life cycle of eels and needs to be considered in stock management and restocking programs.

  6. Apollo 15 yellow impact glasses: Chemistry, petrology, and exotic origin

    SciTech Connect

    Delano, J.W.; Lindsley, D.H.; Ma, M.; Schmitt, R.A.

    1982-11-15

    The Apollo 15 yellow impact glasses are characterized by moderate TiO/sub 2/ (approx.4.8%) and high abundances of the large ion lithophile elements (e.g., K, P, Hf, Th, REE). Since the chemistry of these glasses cannot be duplicated by any combination of local components presently known to occur at the Apollo 15 landing site, these yellow glasses seem to be exotic to that area. Chemical and petrologic constraints suggest that these samples were produced by impact melting of an immature mare regolith developed upon an unusual variety of mare basalt. We speculate that the target basalt were the youngest lava flows known to exist on the moon (i.e., Eratosphenian-age lavas in Oceanus Procellarum and Mare Imbrium). Specific tests are proposed for evaluating this provocative hypothesis.

  7. Origin of asteroid rotation rates in catastrophic impacts.

    PubMed

    Love, S G; Ahrens, T J

    1997-03-13

    The rotation rates of asteroids, which are deduced from periodic fluctuations in their brightnesses, are controlled by mutual collisions. The link between asteroid spin and collision history is usually made with reference to impact experiments on centimetre-scale targets, where material strength governs the impact response. Recent work, however, indicates that for objects of the size of most observed asteroids (> or = 1 km in diameter), gravity rather than intrinsic strength controls the dynamic response to collisions. Here we explore this idea by modelling the effect of impacts on large gravitating bodies. We find that the fraction of a projectile's angular momentum that is retained by a target asteroid is both lower and more variable than expected from laboratory experiments, with spin evolution being dominated by 'catastrophic' collisions that eject approximately 50 per cent of the target's mass. The remnant of an initially non-rotating silicate asteroid that suffers such a collision rotates at a rate of approximately 2.9 per day, which is close to the observed mean asteroid rotation rate of approximately 2.5 d-1. Moreover, our calculations suggest that the observed trend in the mean spin frequency for different classes of asteroids (2.2 d-1 for C-type asteroids, 2.5 d-1 for S-type, and 4.0 d-1 for M-type) is due to increasing mean density, rather than increasing material strength.

  8. The Big Money Question: Action Research Projects Give District a Clear Picture of Professional Learning's Impact

    ERIC Educational Resources Information Center

    Dill-Varga, Barbara

    2015-01-01

    How do districts know if the resources they have allocated to support professional learning in their school district are actually improving the quality of teaching and impacting student performance? In an increasingly challenging financial environment, this is important to know. In this article, a Chicago-area district facing a budget deficit…

  9. Critical Review of Technical Questions Facing Low Impact Development and Green Infrastructure: A Perspective from the Great Plains.

    PubMed

    Vogel, Jason R; Moore, Trisha L; Coffman, Reid R; Rodie, Steven N; Hutchinson, Stacy L; McDonough, Kelsey R; McLemore, Alex J; McMaine, John T

    2015-09-01

    Since its inception, Low Impact Development (LID) has become part of urban stormwater management across the United States, marking progress in the gradual transition from centralized to distributed runoff management infrastructure. The ultimate goal of LID is full, cost-effective implementation to maximize watershed-scale ecosystem services and enhance resilience. To reach that goal in the Great Plains, the multi-disciplinary author team presents this critical review based on thirteen technical questions within the context of regional climate and socioeconomics across increasing complexities in scale and function. Although some progress has been made, much remains to be done including continued basic and applied research, development of local LID design specifications, local demonstrations, and identifying funding mechanisms for these solutions. Within the Great Plains and beyond, by addressing these technical questions within a local context, the goal of widespread acceptance of LID can be achieved, resulting in more effective and resilient stormwater management. PMID:26961478

  10. Critical Review of Technical Questions Facing Low Impact Development and Green Infrastructure: A Perspective from the Great Plains.

    PubMed

    Vogel, Jason R; Moore, Trisha L; Coffman, Reid R; Rodie, Steven N; Hutchinson, Stacy L; McDonough, Kelsey R; McLemore, Alex J; McMaine, John T

    2015-09-01

    Since its inception, Low Impact Development (LID) has become part of urban stormwater management across the United States, marking progress in the gradual transition from centralized to distributed runoff management infrastructure. The ultimate goal of LID is full, cost-effective implementation to maximize watershed-scale ecosystem services and enhance resilience. To reach that goal in the Great Plains, the multi-disciplinary author team presents this critical review based on thirteen technical questions within the context of regional climate and socioeconomics across increasing complexities in scale and function. Although some progress has been made, much remains to be done including continued basic and applied research, development of local LID design specifications, local demonstrations, and identifying funding mechanisms for these solutions. Within the Great Plains and beyond, by addressing these technical questions within a local context, the goal of widespread acceptance of LID can be achieved, resulting in more effective and resilient stormwater management.

  11. DETECTING AND MITIGATING THE ENVIRONMENTAL IMPACT OF FECAL PATHOGENS ORIGINATING FROM CONFINED ANIMAL FEEDING OPERATIONS: REVIEW

    EPA Science Inventory

    This report presents a review of literature regarding the potential impact of fecal pathogens originating from animal agriculture in the United States. Livestock production and dairy operations continue their trend toward larger and more concentrated facilities. These operations ...

  12. Origin and Impact of Phototransduction Noise in Primate Cone Photoreceptors

    PubMed Central

    Angueyra, Juan Manuel; Rieke, Fred

    2013-01-01

    Noise in the responses of cone photoreceptors sets a fundamental limit to visual sensitivity, yet the origin of noise in mammalian cones and its relation to behavioral sensitivity are poorly understood. Our work here on primate cones improves understanding of these issues in three ways. First, we find that cone noise is not dominated by spontaneous photopigment activation or by quantal fluctuations in photon absorption but instead by other sources, namely channel noise and fluctuations in cGMP. Second, we find that adaptation in cones, unlike that in rods, affects signals and noise differently. This difference helps explain why thresholds for rod- and cone-mediated signals have different dependencies on background light level. Third, past estimates of noise in mammalian cones are too high to explain behavioral sensitivity. Our measurements indicate a lower level of cone noise, and thus help reconcile physiological and behavioral estimates of cone noise and sensitivity. PMID:24097042

  13. A giant impact origin of Pluto-Charon.

    PubMed

    Canup, Robin M

    2005-01-28

    Pluto and its moon, Charon, are the most prominent members of the Kuiper belt, and their existence holds clues to outer solar system formation processes. Here, hydrodynamic simulations are used to demonstrate that the formation of Pluto-Charon by means of a large collision is quite plausible. I show that such an impact probably produced an intact Charon, although it is possible that a disk of material orbited Pluto from which Charon later accumulated. These findings suggest that collisions between 1000-kilometer-class objects occurred in the early inner Kuiper belt.

  14. A giant impact origin of Pluto-Charon.

    PubMed

    Canup, Robin M

    2005-01-28

    Pluto and its moon, Charon, are the most prominent members of the Kuiper belt, and their existence holds clues to outer solar system formation processes. Here, hydrodynamic simulations are used to demonstrate that the formation of Pluto-Charon by means of a large collision is quite plausible. I show that such an impact probably produced an intact Charon, although it is possible that a disk of material orbited Pluto from which Charon later accumulated. These findings suggest that collisions between 1000-kilometer-class objects occurred in the early inner Kuiper belt. PMID:15681378

  15. Origins.

    ERIC Educational Resources Information Center

    Online-Offline, 1999

    1999-01-01

    Provides an annotated list of resources dealing with the theme of origins of life, the universe, and traditions. Includes Web sites, videos, books, audio materials, and magazines with appropriate grade levels and/or subject disciplines indicated; professional resources; and learning activities. (LRW)

  16. Microanalysis of Hypervelocity Impact Residues of Possible Interstellar Origin

    NASA Technical Reports Server (NTRS)

    Stroud, Rhonda M.; Achilles, Cheri; Allen, Carlton; Anasari, Asna; Bajt, Sasa; Bassim, Nabil; Bastien, Ron S.; Bechtel, H. A.; Borg, Janet; Brenker, Frank E.; Bridges, John; Brownlee, Donald E.; Burchell, Mark; Burghammer, Manfred; Butterworth, Anna L.; Changela, Hitesh; Cloetens, Peter; Davis, Andrew M.; Doll, Ryan; Floss, Christine; Flynn, George; Fougeray, Patrick; Frank, David; Sandford, Scott A.; Zolensky, Michael E.

    2012-01-01

    The NASA Stardust spacecraft deployed two collector trays, one dedicated to the collection of dust from Comet Wild 2, and the other for the capture of interstellar dust (ISD). The samples were returned successfully to Earth in 2006, and now provide an unprecedented opportunity for laboratory-based microanalysis of materials from the outer solar system and beyond. Results from the cometary sample studies have demonstrated that Wild 2 contains much more refractory condensate material and much less pristine extra-solar material than expected, which further indicates that there was significant transport of inner solar system materials to the Kuiper Belt in the early solar system [1]. The analysis of the interstellar samples is still in the preliminary examination (PE) phase, due to the level of difficulty in the definitive identification of the ISD features, the overall low abundance, and its irreplaceable nature, which necessitates minimally invasive measurements [2]. We present here coordinated microanalysis of the impact features on the Al foils, which have led to the identification of four impacts that are possibly attributable to interstellar dust. Results from the study of four ISD candidates captured in aerogel are presented elsewhere [2].

  17. Impact Crater Hydrothermal Niches for Life on Mars: Question of Scale

    NASA Technical Reports Server (NTRS)

    Pope, K. O.; Ames, D. E.; Kieffer, S. W.; Ocampo, A. C.

    2000-01-01

    A major focus in the search for fossil life on Mars is on ancient hydrothermal deposits. Nevertheless, remote sensing efforts have not found mineral assemblages characteristic of hydrothermal activity. Future remote sensing work, including missions with higher spatial resolution, may detect localized hydrothermal deposits, but it is possible that dust mantles will prohibit detection from orbit and lander missions will be required. In anticipation of such missions, it is critical to develop a strategy for selecting potential hydrothermal sites on Mars. Such a strategy is being developed for volcanogenic hydrothermal systems, and a similar strategy is needed for impact hydrothermal systems.

  18. Physical impacts of regional climate change in the West African Sahel and the question of desertification

    SciTech Connect

    Nicholson, S.E.; Ba, M.

    1997-11-01

    The question of desertification is examined in the West African Sahel region by considering various physical indicators assumed to accompany this process. The study considers only the past 14 years, since the availability of comprehensive satellite data sets. The physical indicators examined include vegetation cover, surface albedo, soil moisture, wind-borne dust, river flow, lakes, and the ratio of available moisture to vegetation growth. Vegetation cover and albedo are assessed from satellite data. Soil moisture is assessed using a surface hydrologic model. Dust is estimated from visibility measurements. The most important results are that: (1) there is no progressive change in the vegetation cover, (2) an increase of albedo as the region dries up cannot be documented, and (3) there has been a tremendous increase in wind-borne dust over the Sahel. The vegetation cover responds almost directly to rainfall and the movement of the desert boundary corresponds roughly to rainfall fluctuations. The most important meteorological effect of the drought and/or desertification in the Sahel may be the enhanced dust generation, with the region becoming a major global source of atmospheric mineral dust. 5 refs., 7 figs., 1 tab.

  19. Origins.

    PubMed

    Weinberg, S

    1985-10-01

    The farthest of the galaxies that can be seen through the large ground-based telescopes of modern astronomy, such as those on La Palma in the Canary Islands, are so far away that they appear as they did close to the time of the origin of the universe, perhaps some 10 billion years ago. Much has been learned, and much has still to be learned, about the young universe from optical and radio telescopes, but these instruments cannot be used to look directly at the universe in its first few hundred thousand years. Instead, they are used to search the relatively recent past for relics of much earlier times. Together with experiments planned for the next generation of elementary particle accelerators, astronomical observations should continue to extend what is known about the universe backward in time to the Big Bang and may eventually help to reveal the origins of the physical laws that govern the universe.

  20. Questions concerning the potential impact of glyphosate-based herbicides on amphibians.

    PubMed

    Wagner, Norman; Reichenbecher, Wolfram; Teichmann, Hanka; Tappeser, Beatrix; Lötters, Stefan

    2013-08-01

    Use of glyphosate-based herbicides is increasing worldwide. The authors review the available data related to potential impacts of these herbicides on amphibians and conduct a qualitative meta-analysis. Because little is known about environmental concentrations of glyphosate in amphibian habitats and virtually nothing is known about environmental concentrations of the substances added to the herbicide formulations that mainly contribute to adverse effects, glyphosate levels can only be seen as approximations for contamination with glyphosate-based herbicides. The impact on amphibians depends on the herbicide formulation, with different sensitivity of taxa and life stages. Effects on development of larvae apparently are the most sensitive endpoints to study. As with other contaminants, costressors mainly increase adverse effects. If and how glyphosate-based herbicides and other pesticides contribute to amphibian decline is not answerable yet due to missing data on how natural populations are affected. Amphibian risk assessment can only be conducted case-specifically, with consideration of the particular herbicide formulation. The authors recommend better monitoring of both amphibian populations and contamination of habitats with glyphosate-based herbicides, not just glyphosate, and suggest including amphibians in standardized test batteries to study at least dermal administration.

  1. Chesapeake Bay Crater, Virginia: Confirmation of Impact Origin

    NASA Astrophysics Data System (ADS)

    Koeberl, C.; Reimold, W. U.; Brandt, D.; Poag, C. W.

    1995-09-01

    Poag et al. [1] identified a late Eocene boulder bed in drill cores from southeast Virginia, and interpreted it as an impact-generated tsunami deposit. Seismic studies and other geophysical evidence indicated the existence of a possible impact structure centered at Chesapeake Bay (37 degrees x 15' N and 76 degrees x 04' W), which may be 85-90 km in diameter [2]. Four drill cores have penetrated into the breccia, although none is available from the center of the structure, or reaches basement. A central peak-ring of crystalline rocks with about 25 km diameter is surrounded by a 30 km-wide annular trough and terrace terrane. The trough is filled with polymictic breccia composed mainly of autochthonous sedimentary clasts in a sandy matrix with some angular clasts of granitic and metasedimentary basement rocks [2]. The Chesapeake Bay crater is of special interest, because it is close to the region identified as the possible source region for the North American tektites, is of about the expected size, and has an age identical to that of the tektites [3]. While the source craters for the Central European and Ivory Coast tektite strewn fields are known, the source crater of the North American tektites has remained elusive. A variety of locations were suggested, including Popigai (Siberia), Wanapitei (Canada), Mistastin (Canada), and Bee Bluff (Texas), but all were later discounted. The distribution of the tektites and microtektites in the strewn field suggests that the North American tektite source crater is likely to be located at or near the eastern coast of the North American continent, maybe underwater [4,5]. The location of the Chesapeake Bay structure is in agreement with the area suggested before [4,5]. We have started a petrological and geochemical study of target rocks and breccias from the Chesapeake Bay structure. We analyzed the major and trace element composition of 17 mainly sedimentary samples, for comparison with North American tektite values. 14 of these

  2. Origins of task-specific sensory-independent organization in the visual and auditory brain: neuroscience evidence, open questions and clinical implications.

    PubMed

    Heimler, Benedetta; Striem-Amit, Ella; Amedi, Amir

    2015-12-01

    Evidence of task-specific sensory-independent (TSSI) plasticity from blind and deaf populations has led to a better understanding of brain organization. However, the principles determining the origins of this plasticity remain unclear. We review recent data suggesting that a combination of the connectivity bias and sensitivity to task-distinctive features might account for TSSI plasticity in the sensory cortices as a whole, from the higher-order occipital/temporal cortices to the primary sensory cortices. We discuss current theories and evidence, open questions and related predictions. Finally, given the rapid progress in visual and auditory restoration techniques, we address the crucial need to develop effective rehabilitation approaches for sensory recovery.

  3. Origins of task-specific sensory-independent organization in the visual and auditory brain: neuroscience evidence, open questions and clinical implications.

    PubMed

    Heimler, Benedetta; Striem-Amit, Ella; Amedi, Amir

    2015-12-01

    Evidence of task-specific sensory-independent (TSSI) plasticity from blind and deaf populations has led to a better understanding of brain organization. However, the principles determining the origins of this plasticity remain unclear. We review recent data suggesting that a combination of the connectivity bias and sensitivity to task-distinctive features might account for TSSI plasticity in the sensory cortices as a whole, from the higher-order occipital/temporal cortices to the primary sensory cortices. We discuss current theories and evidence, open questions and related predictions. Finally, given the rapid progress in visual and auditory restoration techniques, we address the crucial need to develop effective rehabilitation approaches for sensory recovery. PMID:26469211

  4. The Impact of Asking Intention or Self-Prediction Questions on Subsequent Behavior: A Meta-Analysis.

    PubMed

    Wood, Chantelle; Conner, Mark; Miles, Eleanor; Sandberg, Tracy; Taylor, Natalie; Godin, Gaston; Sheeran, Paschal

    2016-08-01

    The current meta-analysis estimated the magnitude of the impact of asking intention and self-prediction questions on rates of subsequent behavior, and examined mediators and moderators of this question-behavior effect (QBE). Random-effects meta-analysis on 116 published tests of the effect indicated that intention/prediction questions have a small positive effect on behavior (d+ = 0.24). Little support was observed for attitude accessibility, cognitive dissonance, behavioral simulation, or processing fluency explanations of the QBE. Multivariate analyses indicated significant effects of social desirability of behavior/behavior domain (larger effects for more desirable and less risky behaviors), difficulty of behavior (larger effects for easy-to-perform behaviors), and sample type (larger effects among student samples). Although this review controls for co-occurrence of moderators in multivariate analyses, future primary research should systematically vary moderators in fully factorial designs. Further primary research is also needed to unravel the mechanisms underlying different variants of the QBE.

  5. Radiative Impacts of Elevated Aerosol Layers from Different Origins

    NASA Astrophysics Data System (ADS)

    Sauer, D. N.; Weinzierl, B.; Gasteiger, J.; Heimerl, K.

    2014-12-01

    Aerosol particles are omnipresent in the Earth's atmosphere and have important impacts on weather and climate by their effects on the atmospheric radiative balance. With the advent of more and more sophisticated representations of atmospheric processes in earth system models, the lack of reliable input data on aerosols leads to significant uncertainties in the prediction of future climate scenarios. In recent years large discrepancies in radiative forcing estimates from aerosol layers in modeling studies have been revealed emphasizing the need for detailed and systematic observations of aerosols. Airborne in-situ measurements represent an important pillar for validating both model results and retrievals of aerosol distributions and properties from remote sensing methods on global scales. However, detailed observations are challenging and therefore are subject to substantial uncertainties themselves. Here we use data from airborne in-situ measurements of elevated aerosol layers from various field experiments in different regions of the world. The data set includes Saharan mineral dust layers over Africa, the Atlantic Ocean and the Caribbean from the SALTRACE and the SAMUM campaigns as well as long-range transported biomass burning aerosol layers from wild fires in the Sahel region and North America measured over the tropical Atlantic Ocean, Europe and the Arctic detected during SAMUM2, CONCERT2011, DC3 and ACCESS 2012. We aim to characterize the effects of the measured aerosol layers, in particular with respect to ageing, mixing state and vertical structure, on the overall atmospheric radiation budget as well as local heating and cooling rates. We use radiative transfer simulations of short and long-wave radiation and aerosol optical properties derived in a consistent way from the in-situ observations of microphysical properties using T-matrix calculations. The results of this characterization will help to improve the parameterization of the effects of elevated

  6. Negative Questions in Chinese

    ERIC Educational Resources Information Center

    Yat-shing, Cheung

    1974-01-01

    Mainly concerned with where negative questions in Chinese originate.An abstract treatment allows the derviation of all questions from a general underlying structure with disjunctive pattern and accounts for the discordance between the answer to a negative question and its answer particle. (Author/RM)

  7. Constraining the Origin of Impact Craters on Al Foils from the Stardust Interstellar Dust Collector

    NASA Technical Reports Server (NTRS)

    Stroud, Rhonda M.; Achilles, Cheri; Allen, Carlton; Ansari, Asna; Bajt, Sasa; Bassim, Nabil; Bastien, Ron S.; Bechtel, H. A.; Borg, Janet; Brenker, Frank E.; Bridges, John; Brownlee, Donald E.; Burchell, Mark; Burghammer, Manfred; Butterworth, Anna L.; Changela, Hitesh; Cloetens, Peter; Davis, Andrew M.; Doll, Ryan; Floss, Christine; Flynn, George; Fougeray, Patrick; Frank, David; Sandford, Scott A.; Zolensky, Michael E.

    2012-01-01

    Preliminary examination (PE) of the aerogel tiles and Al foils from the Stardust Interstellar Dust Collector has revealed multiple impact features. Some are most likely due to primary impacts of interstellar dust (ISD) grains, and others are associated with secondary impacts of spacecraft debris, and possibly primary impacts of interplanetary dust particles (IDPs) [1, 2]. The current focus of the PE effort is on constraining the origin of the individual impact features so that definitive results from the first direct laboratory analysis of contemporary ISD can be reported. Because crater morphology depends on impacting particle shape and composition, in addition to the angle and direction of impact, unique particle trajectories are not easily determined. However, elemental analysis of the crater residues can distinguish real cosmic dust from the spacecraft debris, due to the low cosmic abundance of many of the elements in the spacecraft materials. We present here results from the elemental analysis of 24 craters and discuss the possible origins of 4 that are identified as candidate ISD impacts

  8. Everyone Wins: A Mars-Impact Origin for Carbonaceous Phobos and Deimos

    NASA Technical Reports Server (NTRS)

    Fries, M.; Welzenbach, L.; Steele, A.

    2016-01-01

    Discussions of Phobos' and Deimos' origin(s) tend to feature an orthogonally opposed pair of observations: dynamical studies which favor coalescence of the moons from an orbital debris ring arising from a large impact on Mars; and reflectance spectroscopy of the moons that indicate a carbonaceous composition that is not consistent with Martian surface materials. One way to reconcile this discrepancy is to consider the option of a Mars-impact origin for Phobos and Deimos, followed by surficial decoration of carbon-rich materials by interplanetary dust particles (IDP). The moons experience a high IDP flux because of their location in Mars' gravity well. Calculations show that accreted carbon is sufficient to produce a surface with reflectance spectra resembling carbonaceous chondrites.

  9. Impact of solar system exploration on theories of chemical evolution and the origin of life

    NASA Technical Reports Server (NTRS)

    Devincenzi, D. L.

    1983-01-01

    The impact of solar system exploration on theories regarding chemical evolution and the origin of life is examined in detail. Major findings from missions to Mercury, Venus, the moon, Mars, Jupiter, Saturn, and Titan are reviewed and implications for prebiotic chemistry are discussed. Among the major conclusions are: prebiotic chemistry is widespread throughout the solar system and universe; chemical evolution and the origin of life are intimately associated with the origin and evolution of the solar system; the rate, direction, and extent of prebiotic chemistry is highly dependent upon planetary characteristics; and continued exploration will increase understanding of how life originated on earth and allow better estimates of the likelihood of similar processes occurring elsewhere.

  10. Suevite breccia from the Ries crater, Germany: Origin, cooling history and devitrification of impact glasses

    NASA Astrophysics Data System (ADS)

    Engelhardt, W. V.; Arndt, J.; Fecker, B.; Pankau, H. G.

    1995-05-01

    The distribution and petrography of surficial suevite breccias of the Ries impact crater in Southern Germany are reviewed, and the morphology, petrography and chemical composition of impact glasses in suevite breccias and their postdepositional devitrification is synthesized. Origin and thermal history of suevite breccia and suevite glasses are inferred from these data and from recent results of cooling and crystallization experiments with suevite glass melts under controlled conditions. In a montmorillonitic groundmass, the suevite breccia contains pieces of glass, up to some decimeters in size, and crystalline rock clasts of all stages of shock metamorphism. The glass particles originated in impact melt of basement gneisses and cooled by adiabatic pressure release from ˜80 GPa to atmospheric pressure during ejection from the crater. They were deposited on the ground together with the other suevite components at a temperature of ˜750 °C. Fractured glass pieces in the breccia show that during deposition of the suevite the temperature was below the temperature at which undercooled melt transforms to rigid glass. The suevite cooled after deposition mainly by convection of heat by emanating gases and vapors. In chilled layers at the base and at the top of suevite deposits, the glasses are preserved in vitreous state. Between these zones, the glasses were devitrified, yet crystallization of pyroxene, plagioclase and magnetite took place below the glass-transformation temperature. Annealing experiments show that this unusual devitrification below the transformation temperature can be explained by the impact origin of suevite glasses. Due to rapid adiabatic cooling on decompression, the glasses were oversaturated with water and internally strained. Under these conditions, devitrification, especially the formation of plagioclase, was possible at temperatures below the transformation range. The origin from adiabatically cooled impact melt of deep-seated rocks

  11. Shocked zircons in the Onaping Formation: Further proof of impact origin

    NASA Technical Reports Server (NTRS)

    Bohor, B. F.; Betterton, W. J.

    1992-01-01

    The Onaping Formation fills the structural basin at Sudbury, Ontario, Canada. This formation is composed of three members: a basal, coarse, mainly quartzitic breccia (Basal Member); a light-colored, heavily included, polymict middle unit (Gray Member); and a similar but dark-colored upper unit (Black Member). Two different origins were proposed for the Onaping: (1) volcanic ash-flow sheet; and (2) impact fall-back ejecta. These origins are critically discussed in a review paper coauthored by proponents of each view.

  12. The origin of the moon and the single-impact hypothesis. I

    NASA Technical Reports Server (NTRS)

    Benz, W.; Slattery, W. L.; Cameron, A. G. W.

    1986-01-01

    One of the newer ideas regarding the origin of the moon is concerned with a single-impact hypothesis. It is pointed out that this theory has the advantage of overcoming most of the difficulties with the classical theories. The angular momentum of the earth-moon system can easily be obtained by varying the initial conditions of the impact. A series of three-dimensional numerical simulations of the collision between the earth and an object of about 1/10 its mass is presented. Different impact velocities, impact parameters, and initial internal energies are considered. Attention is given to assumptions, the equation of state, numerical techniques utilizing the momentum equation and the energy conservation equation, tests, and initial conditions and units.

  13. Questioning Techniques.

    ERIC Educational Resources Information Center

    Patterson, Michelle

    1999-01-01

    Questions are so much a part of the classroom routine and they should stimulate learning and thinking. Introduces the Questioning and Understanding to Improve Learning and Thinking (QUILT) method which incorporates Bloom's Taxonomy and wait time. (ASK)

  14. Four Questions

    ERIC Educational Resources Information Center

    Hark-Weber, Amara G., Ed.

    2013-01-01

    The author is pleased to introduce a new section in "TAJ," Four Questions. The structure is simple: four questions are asked to teaching artists working in various media and locations. The questions are always the same, but because each teaching artist's approach is unique, their answers will provide an insight into particular methodologies that…

  15. Origin of the Moon in a giant impact near the end of the Earth's formation.

    PubMed

    Canup, R M; Asphaug, E

    2001-08-16

    The Moon is generally believed to have formed from debris ejected by a large off-centre collision with the early Earth. The impact orientation and size are constrained by the angular momentum contained in both the Earth's spin and the Moon's orbit, a quantity that has been nearly conserved over the past 4.5 billion years. Simulations of potential moon-forming impacts now achieve resolutions sufficient to study the production of bound debris. However, identifying impacts capable of yielding the Earth-Moon system has proved difficult. Previous works found that forming the Moon with an appropriate impact angular momentum required the impact to occur when the Earth was only about half formed, a more restrictive and problematic model than that originally envisaged. Here we report a class of impacts that yield an iron-poor Moon, as well as the current masses and angular momentum of the Earth-Moon system. This class of impacts involves a smaller-and thus more likely-object than previously considered viable, and suggests that the Moon formed near the very end of Earth's accumulation.

  16. Do You Remember? How Caregivers Question Their Spouses Who Have Alzheimer's Disease and the Impact on Communication

    ERIC Educational Resources Information Center

    Small, Jeff A.; Perry, JoAnn

    2005-01-01

    This study examined the types of questions caregivers use and their outcomes when conversing with their spouse with Alzheimer's disease (AD). Of particular interest was caregivers' use of yes-no and open-ended questions and the demands they make on the memory of the person with AD. It was hypothesized that communication between caregivers and…

  17. Impact Constraints on the Age and Origin of the Crustal Dichotomy on Mars

    NASA Technical Reports Server (NTRS)

    Frey, Herbert V.

    2004-01-01

    MOLA data have revealed a large population of 'Quasi-Circular Depressions' (QCDs) with little or no visible expression in image data. These likely buried impact basins have important implications for the age of the lowland crust, how that compares with original highland crust, and when and how the crustal dichotomy may have formed. The buried lowlands are of Early Noachian age, likely slightly younger than the buried highlands but older than the exposed (visible) highland surface. A depopulation of large visible basins at diameters 800 to 1300 km suggests some global scale event early in martian history, maybe related to the formation of the lowlands and/or the development of Tharsis. A suggested early disappearance of the global magnetic field can be placed within a temporal sequence of formation of the very largest impact basins. The global field appears to have disappeared at about the time the lowlands formed. It seems likely the topographic crustal dichotomy was produced very early in martian history by processes which operated very quickly. This and the preservation of large relic impact basins in the northern hemisphere, which themselves can account for the lowland topography, suggest that large impacts played the major role in the origin Mars fundamental crustal feature.

  18. Impact Constraints on the Age and Origin of the Crustal Dichotomy on Mars

    NASA Technical Reports Server (NTRS)

    Frey, H. V.

    2004-01-01

    MOLA data have revealed a large population of "Quasi-Circular Depressions" (QCDs) with little or no visible expression in image data. These likely buried impact basins have important implications for the age of the lowland crust, how that compares with original highland crust, and when and how the crustal dichotomy may have formed. The buried lowlands are of Early Noachian age, likely slightly younger than the buried highlands but older than the exposed (visible) highland surface. A depopulation of large visible basins at diameters 800 to 1300 km suggests some global scale event early in martian history, maybe related to the formation of the lowlands andor the development of Tharsis. A suggested early disappearance of the global magnetic field can be placed within a temporal sequence of formation of the very largest impact basins. The global field appears to have disappeared at about the time the lowlands formed. It seems likely the topographic crustal dichotomy was produced very early in martian history by processes which operated very quickly. This and the preservation of large relic impact basins in the north- em hemisphere, which themselves can account for the lowland topography, suggest that large impacts played the major role in the origin Mars fundamental crustal feature.

  19. To Question or Not to Question: That Seems to Be the Question.

    ERIC Educational Resources Information Center

    Bradtmueller, Weldon G.; Egan, James B.

    Research on the effects of questioning in the classroom has explored the placement, timing, type, and social impact of questions. Principles of good questioning include the following: (1) well-stated questions should be concise, clear, and complete; (2) questions should be topical in nature, requiring a complex answer; (3) yes or no questions…

  20. Novel Word Learning of Preschoolers Enrolled in Head Start Regular and Bilingual Classrooms: Impact of Adult Vocabulary Noneliciting Questions during Shared Storybook Reading

    ERIC Educational Resources Information Center

    Walsh, Bridget A.

    2009-01-01

    This dissertation study employed quantitative methods to investigate the impact of adult questioning styles on children's novel vocabulary acquisition during shared storybook reading. In an effort to examine adult qualitative variations in shared storybook readings, two experiments were conducted to assess the effect of noneliciting questions…

  1. The Shedler-Westen Assessment Procedure (SWAP): Evaluating Psychometric Questions about Its Reliability, Validity, and Impact of Its Fixed Score Distribution

    ERIC Educational Resources Information Center

    Blagov, Pavel S.; Bi, Wu; Shedler, Jonathan; Westen, Drew

    2012-01-01

    The Shedler-Westen Assessment Procedure (SWAP) is a personality assessment instrument designed for use by expert clinical assessors. Critics have raised questions about its psychometrics, most notably its validity across observers and situations, the impact of its fixed score distribution on research findings, and its test-retest reliability. We…

  2. Are Extracted Materials Truly Representative of Original Samples? Impact of C18 Extraction on CDOM Optical and Chemical Properties.

    PubMed

    Andrew, Andrea A; Del Vecchio, Rossana; Zhang, Yi; Subramaniam, Ajit; Blough, Neil V

    2016-01-01

    Some properties of dissolved organic matter (DOM) and chromophoric dissolved organic matter (CDOM) can be easily measured directly on whole waters, while others require sample concentration and removal of natural salts. To increase CDOM content and eliminate salts, solid phase extraction (SPE) is often employed. Biases following extraction and elution are inevitable, thus raising the question of how truly representative the extracted material is of the original. In this context, we investigated the wavelength dependence of extraction efficiency for C18 cartridges with respect to CDOM optical properties using samples obtained from the Middle Atlantic Bight (MAB) and the Equatorial Atlantic Ocean (EAO). Further, we compared the optical changes of C18 extracts and the corresponding whole water following chemical reduction with sodium borohydride (NaBH4). C18 cartridges preferentially extracted long-wavelength absorbing/emitting material for samples impacted by riverine input. Extraction efficiency overall decreased with offshore distance away from riverine input. Spectral slopes of C18-OM samples were also almost always lower than those of their corresponding CDOM samples supporting the preferential extraction of higher molecular weight absorbing material. The wavelength dependence of the optical properties (absorption, fluorescence emission, and quantum yield) of the original water samples and their corresponding extracted material were very similar. C18 extracts and corresponding water samples further exhibited comparable optical changes following NaBH4 reduction, thus suggesting a similarity in nature (structure) of the optically active extracted material, independent of geographical locale. Altogether, these data suggested a strong similarity between C18 extracts and corresponding whole waters, thus indicating that extracts are representative of the CDOM content of original waters.

  3. Are Extracted Materials Truly Representative of Original Samples? Impact of C18 Extraction on CDOM Optical and Chemical Properties

    PubMed Central

    Andrew, Andrea A.; Del Vecchio, Rossana; Zhang, Yi; Subramaniam, Ajit; Blough, Neil V.

    2016-01-01

    Some properties of dissolved organic matter (DOM) and chromophoric dissolved organic matter (CDOM) can be easily measured directly on whole waters, while others require sample concentration and removal of natural salts. To increase CDOM content and eliminate salts, solid phase extraction (SPE) is often employed. Biases following extraction and elution are inevitable, thus raising the question of how truly representative the extracted material is of the original. In this context, we investigated the wavelength dependence of extraction efficiency for C18 cartridges with respect to CDOM optical properties using samples obtained from the Middle Atlantic Bight (MAB) and the Equatorial Atlantic Ocean (EAO). Further, we compared the optical changes of C18 extracts and the corresponding whole water following chemical reduction with sodium borohydride (NaBH4). C18 cartridges preferentially extracted long-wavelength absorbing/emitting material for samples impacted by riverine input. Extraction efficiency overall decreased with offshore distance away from riverine input. Spectral slopes of C18-OM samples were also almost always lower than those of their corresponding CDOM samples supporting the preferential extraction of higher molecular weight absorbing material. The wavelength dependence of the optical properties (absorption, fluorescence emission, and quantum yield) of the original water samples and their corresponding extracted material were very similar. C18 extracts and corresponding water samples further exhibited comparable optical changes following NaBH4 reduction, thus suggesting a similarity in nature (structure) of the optically active extracted material, independent of geographical locale. Altogether, these data suggested a strong similarity between C18 extracts and corresponding whole waters, thus indicating that extracts are representative of the CDOM content of original waters. PMID:26904536

  4. Evidence for an Extraterrestrial Impact Origin of the Carolina Bays on the Atlantic Coast of North America

    NASA Astrophysics Data System (ADS)

    Howard, G. A.; West, A.; Firestone, R. B.; Kennett, J. P.; Kimbel, D.; Newell, W.; Kobres, R.

    2007-05-01

    The Carolina Bays, one of the most conspicuous geomorphic features on the Atlantic Coastal Plain of the United States, are a group of about 500,000, oriented, crater-like, elliptical lakes, wetlands, and depressions, ranging from a few dozen meters to about 11 km in length. Although long proposed as impact structures (Melton and Schriever, 1933; Prouty, 1934), this origin for the Carolina Bays has remained controversial mainly because of an apparent absence of associated extraterrestrial materials. Analyses of Bay orientation showed that their long axes converge near the Great Lakes, suggesting that an impact or airburst over that region may have formed the Bays (Eyton and Parkhurst, 1975). However, Bays dates have been reported over a wide range, calling into question whether all Carolina Bays could have formed simultaneously, although this issue remains unresolved and controversial. Many Bay researchers, who subscribe to widely differing theories, agree that modern Carolina Bays have been subject to repeated modification and that they most likely evolved from some type of ancestral depressions. Now for the first time, we present conclusive geochemical and sedimentary evidence in support of an extraterrestrial connection for the Carolina Bays. Analyses of sediment from the rim sands and basins of fifteen Bays, widely distributed across North and South Carolina, reveal anomalously high abundances of microspherules, iridium, fullerenes with ET helium, carbon spherules, glass-like carbon, and other potential markers for extraterrestrial impact. No such markers were found in paleosols beneath the rim sands or basal sediments of the Bays examined. The assemblage of geochemical and sediment signatures of extraterrestrial impact found in Bay sediments are essentially the same as in the pan-North-American Younger Dryas impact boundary layer (the YDB), dated at 12.9 ka. We hypothesize that at least some Bays were formed by the YD impact during the last deglacial, and we

  5. Impact of iron contamination in multicrystalline silicon solarcells: origins, chemical states, and device impacts

    SciTech Connect

    Buonassisi, Tonio; Heuer, Matthias; Istratov, Andrei A.; Marcus,Matthew A.; Jonczyk, Ralf; Lai, Barry; Cai, Zhonghou; Schindler, Roland; Weber, Eicke R.

    2004-11-08

    Synchrotron-based microprobe techniques have been applied to study the distribution, size, chemical state, and recombination activity of Fe clusters in two types of mc-Si materials: block cast mc-Si, and AstroPower Silicon Film(TM) sheet material. In sheet material, high concentrations of metals were found at recombination-active, micron-sized intragranular clusters consisting of micron and sub-micron sized particles. In addition, Fe nanoparticles were located in densities of {approx}2'107 cm-2 along recombination-active grain boundaries. In cast mc-Si,two types of particles were identified at grain boundaries: (1) micron-sized oxidized Fe particles accompanied by other metals (Cr, Mn, Ca, Ti), and (2) a higher number of sub-micron FeSi2 precipitates that exhibited a preferred orientation along the crystal growth direction. In both materials, it is believed that the larger Fe clusters are inclusions of foreign particles, from which Fe dissolves in the melt to form the smaller FeSi2 nanoprecipitates, which by virtue of their more homogeneous distribution are deemed more dangerous to solar cell device performance. Based on this understanding, strategies proposed to reduce the impact of Fe on mc-Si electrical properties include gettering, passivation, and limiting the dissolution of foreign Fe-rich particles in the melt.

  6. Origin of orbital debris impacts on Long Duration Exposure Facility's (LDEF) trailing surfaces

    NASA Technical Reports Server (NTRS)

    Kessler, Donald J.

    1992-01-01

    Orbital debris tracked by the US Space Command is mostly in near circular orbit around the Earth. If small debris were in the same types of orbits, there would be very few orbital debris impacts on the Long Duration Exposure Facility's (LDEF's) trailing surfaces. However, at least 15 percent of the impacts found on the trailing A03 gold surface was found to be orbital debris impacts. This measurement suggests that the orbital distribution of small debris is not the same as that of larger debris. Although this is not a total surprise, since modelling of satellite breakups has predicted different distributions, it does raise questions as to what types of orbits could be responsible for these impacts. A model was developed to explain these LDEF results. The model calculates the expected debris impact crater distribution around LDEF, as a function of debris orbital parameters. The results show that only low inclination and highly elliptical orbits could be responsible for these impacts. The most common object left in this type of orbit is an orbital transfer stage, used by the US and ESA to place objects into geosynchronous orbit, and inclinations near 28 and 7 degrees for the US and ESA, respectively. Even large fragments from satellites, which break up in these types of orbits, are difficult to observe from the ground; consequently, little is known about the number and characteristics of breakups in these orbits. The LDEF data suggest that these objects are breaking up. The LDEF data also suggest that the ratio of the contribution of small debris from this type of orbit to the contribution from circular orbits is about an order of magnitude larger than the same ratio for debris tracked by the US Space Command.

  7. Question Mapping

    ERIC Educational Resources Information Center

    Martin, Josh

    2012-01-01

    After accepting the principal position at Farmersville (TX) Junior High, the author decided to increase instructional rigor through question mapping because of the success he saw using this instructional practice at his prior campus. Teachers are the number one influence on student achievement (Marzano, 2003), so question mapping provides a…

  8. The origin of the moon.

    PubMed

    Boss, A P

    1986-01-24

    The origin of the moon is considered within the theory of formation of the terrestrial planets by accumulation of planetesimals. The theory predicts the occurrence of giant impacts, suggesting that the moon formed after a roughly Mars-sized body impacted on the protoearth. The impact blasted portions of the protoearth and the impacting body into geocentric orbit, forming a prelunar disk from which the moon later accreted. Although other mechanisms for formation of the moon appear to be dynamically impossible or implausible, fundamental questions must be answered before a giant impact origin can be considered both possible and probable.

  9. The origin of the moon and the single impact hypothesis. III

    NASA Technical Reports Server (NTRS)

    Benz, W.; Cameron, A. G. W.; Melosh, H. J.

    1989-01-01

    Calculations of the single-impact hypothesis for the origin of the moon were performed using the smoothed particle hydrodynamics (SPH) code developed by Benz et al. (1986). Results are presented from calculations of a relatively low-level collision with an impactor mass in the range 6-8 x 10 to the 26th g. Several runs of the calculations are conducted for this mass range with variations in the SPH code, the equation of state, and the initial planetary models. The effects of these variations are compared. It is found that the orbiting mass is injected by gravitational torques.

  10. The anti-DNA antibody: origin and impact, dogmas and controversies.

    PubMed

    Rekvig, Ole P

    2015-09-01

    The inclusion of 'the anti-DNA antibody' by the ACR and the Systemic Lupus International Collaborating Clinics (SLICC) as a criterion for systemic lupus erythematosus does not convey the diverse origins of these antibodies, whether their production is transient or persistent (which is heavily influenced by the nature of the inducing antigens), the specificities exerted by these antibodies or their clinical impact-or lack thereof. A substantial amount of data not considered in clinical medicine could be added from basic immunology evidence, which could change the paradigms linked to what 'the anti-DNA antibody' is, in a pathogenic, classification or diagnostic context.

  11. The Impact of Guided Student-Generated Questioning on Chemistry Achievement and Self-Efficacy of Elementary Preservice Teachers

    ERIC Educational Resources Information Center

    Moseley, Christine; Bonner, Emily; Ibey, Marilyn

    2016-01-01

    This study investigated the use of Guided Student-Generated Questioning (GSGQ) as a metacognitive instructional strategy to increase chemistry achievement and self-efficacy of elementary preservice teachers. The Chemistry Self-Efficacy Scale (CSES), modified from the Biology Self-Efficacy Scale (BSES),was used to determine elementary preservice…

  12. Shared origin for seven of Mars Trojans - impact ejecta from Mars?

    NASA Astrophysics Data System (ADS)

    Polishook, David; Jacobson, Seth A.; Aharonson, Oded

    2016-10-01

    Seven out of nine Mars Trojans belong to an orbital grouping that started to spread about 109 years ago (Cuk et al. 2015). We spectrally observed two of them (311999 and 385250) using the IRTF telescope and found that both present an identical olivine-rich reflectance spectrum, that is similar to the reflectance spectrum of (5261) Eureka, the largest of these seven Trojans (Rivkin et al. 2007). These measurements confirm the shared origin of the seven. Moreover, olivine-rich reflectance spectra is rare within asteroids, but is visible in numerous locations on Mars and is found within SNC meteorites that are argued to originate from Mars (Chassigny, ALHA77005; McSween 1985). This spectral resemblance encourages us to suggest that the seven Trojans are impact ejecta from Mars' plutonic rock. We will present dynamical calculations showing how the impact ejecta could have been caught in L5 and that there are enough size-relevant craters on Mars surface to produce these seven Trojans.

  13. Late Impacts and the Origins of the Atmospheres on the Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.; Stewart, S. T.; Lock, S. J.; Parai, R.; Tucker, J. M.

    2014-12-01

    Models for the origin of terrestrial atmospheres typically require an intricate sequence of events, including hydrodynamic escape, outgassing of mantle volatiles and late delivery. Here we discuss the origin of the atmospheres on the terrestrial planets in light of new ideas about the formation of the Moon, giant impact induced atmospheric loss and recent noble gas measurements. Our new measurements indicate that noble gases in the Earth's atmosphere cannot be derived from any combination of fractionation of a nebular-derived atmosphere followed by outgassing of deep or shallow mantle volatiles. While Ne in the mantle retains a nebular component, the present-day atmosphere has no memory of nebular gases. Rather, atmospheric noble gases have a close affinity to chondrites. On the other hand, Venus's atmosphere has 20 and 70 times higher abundance of 20Ne and 36Ar, respectively, and a 20Ne/22Ne ratio closer to the solar value than Earth's atmosphere. While the present atmosphere of Mars is significantly fractionated in the lighter noble gases due to long term atmospheric escape, the Kr isotopic ratios in Martian atmosphere are identical to solar. Thus, while Earth's atmosphere has no memory of accretion of nebular gases, atmospheres on both Venus and Mars preserve at least a component of nebular gases. To explain the above observations, we propose that a common set of processes operated on the terrestrial planets, and that their subsequent evolutionary divergence is simply explained by planetary size and the stochastic nature of giant impacts. We present geochemical observations and simulations of giant impacts to show that most of Earth's mantle was degassed and the outgassed volatiles were largely lost during the final sequence of giant impacts onto Earth. Earth's noble gases were therefore dominantly derived from late-accreting planetesimals. In contrast, Venus did not suffer substantial atmospheric loss by a late giant impact and retains a higher abundance of

  14. The Calvin 28 cryptoexplosive disturbance, Cass County, Michigan: Evidence for impact origin

    NASA Technical Reports Server (NTRS)

    Milstein, Randall L.

    1988-01-01

    The Calvin 28 cryptoexplosive disturbance is an isolated, nearly circular subsurface structure of Late Ordovician age in southwestern Michigan. The structure is defined by 107 wells, is about 7.24 km in diameter and consists of a central dome, an annular depression and an encircling anticlinal rim. Seismic and geophysical well log data confirm that an intricate system of faults and structural derangement exists within the structure. Deformation decreases with depth and distance from the structure. U.S.G.S. topographic maps and aerial imagery show the structure is reflected as a subtle surface topographic rise controlling local drainage. Igneous or diapiric intrusion and solution collapse are rejected as possible origins for Calvin 28 on the basis of stratigraphic, structural and geophysical evidence. A volcanic origin is inconsistent with calculated energy requirements and an absence of igneous material. Although shock-metamorphic features are unidentified, microbreccias occur in deep wells that penetrate the structure. Morphology and structural parameters support an impact origin.

  15. Geophysical characterization of two circular structures at Bajada del Diablo (Patagonia, Argentina): Indication of impact origin

    NASA Astrophysics Data System (ADS)

    Prezzi, Claudia B.; Orgeira, María Julia; Acevedo, Rogelio D.; Ponce, Juan Federico; Martinez, Oscar; Rabassa, Jorge O.; Corbella, Hugo; Vásquez, Carlos; González-Guillot, Mauricio; Subías, Ignacio

    2012-02-01

    An impact origin has been proposed for the circular structures found in Bajada del Diablo, Patagonia, Argentina. Taking into account its extension and the number of impact structures, Bajada del Diablo would be the largest meteoritic impact areas known on Earth, being an extremely interesting area for the research of impact events and processes. Moreover, the global distribution of known impact structures shows a surprising asymmetry. Particularly, South America has only seven described areas. It is evident that this situation is an artifact, highlighting the importance of intensifying the research in the least studied areas such as Argentina. Circular structures in Bajada del Diablo have been identified on two rock types: the Quiñelaf eruptive complex and Pampa Sastre Formation. In the first case, circular structures are placed in olivine basalts. On the other hand, Pampa Sastre Formation (late Pliocene/early Pleistocene) corresponds to conglomerate layers with basalt clasts boulder and block in size in a coarse sandy matrix. With the aim of further the investigation of the proposed impact origin for these circular structures, we carried out detailed topographic, magnetic and electromagnetic ground surveys in two circular structures ("8" and "A") found in Pampa Sastre conglomerates. Both circular structures are simple, bowl-shaped with rim diameters of 300 m and maximum depths of 10 m. They have been partially filled in by debris flows from the rims and wind-blown sands. Two preliminary magnetic profiles have also been carried out in circular structure "G" found in Quiñelaf basalts. The magnetic anomalies show a circular pattern with a slightly negative and relatively flat signal in the circular structures' bases. Furthermore in the circular structures' rims, high-amplitude, conspicuous and localized (short wavelength) anomalies are observed. Such large amplitude and short wavelength anomalies are not detected outside the circular structures. For all used

  16. The Impact of History on Our Perception of Evolutionary Events: Endosymbiosis and the Origin of Eukaryotic Complexity

    PubMed Central

    Keeling, Patrick J.

    2014-01-01

    Evolutionary hypotheses are correctly interpreted as products of the data they set out to explain, but they are less often recognized as being heavily influenced by other factors. One of these is the history of preceding thought, and here I look back on historically important changes in our thinking about the role of endosymbiosis in the origin of eukaryotic cells. Specifically, the modern emphasis on endosymbiotic explanations for numerous eukaryotic features, including the cell itself (the so-called chimeric hypotheses), can be seen not only as resulting from the advent of molecular and genomic data, but also from the intellectual acceptance of the endosymbiotic origin of mitochondria and plastids. This transformative idea may have unduly affected how other aspects of the eukaryotic cell are explained, in effect priming us to accept endosymbiotic explanations for endogenous processes. Molecular and genomic data, which were originally harnessed to answer questions about cell evolution, now so dominate our thinking that they largely define the question, and the original questions about how eukaryotic cellular architecture evolved have been neglected. This is unfortunate because, as Roger Stanier pointed out, these cellular changes represent life’s “greatest single evolutionary discontinuity,” and on this basis I advocate a return to emphasizing evolutionary cell biology when thinking about the origin of eukaryotes, and suggest that endogenous explanations will prevail when we refocus on the evolution of the cell. PMID:24492708

  17. "The" Question.

    ERIC Educational Resources Information Center

    Lowe, Pardee, Jr.

    1984-01-01

    Examines the suggestions found in Michael Canale's paper, "Considerations in the Testing of Reading and Listening Proficiency," in the light of a possible U.S. Government's Interagency Language Roundtable receptive skills proficiency test which must supply the answer to the question of how well an individual can understand a particular language.…

  18. Questor's Question

    ERIC Educational Resources Information Center

    Erickson, Mary; Dock, Michelle Nichols; Eldridge, Laurie

    2009-01-01

    Questor is a curious little bird whose four broad questions are helpful to anyone interested in making art or understanding the art of others. He was designed as a character in an online video for children, "Building on a River: Questor's Tale." The video is narrated by Questor, who relates the 2000 year history of architecture along the Salt…

  19. Questionable Exercises.

    ERIC Educational Resources Information Center

    Liemohn, Wendell; Haydu, Traci; Phillips, Dawn

    1999-01-01

    This publication presents general guidelines for exercise prescription that have an anatomical basis but also consider the exerciser's ability to do the exercise correctly. It reviews various common questionable exercises, explaining how some exercises, especially those designed for flexibility and muscle fitness, can cause harm. Safer…

  20. Four Questions

    ERIC Educational Resources Information Center

    Hark-Weber, Amara G., Ed.

    2013-01-01

    Teaching artists often find themselves working in schools and communities that are new to them, whether these are situations close to home or farther afield. This issue of Four Questions highlights teaching artists who travel extensively as part of their teaching and artistic practices and bring their expertise, energy, and creativity to…

  1. Origin and diagenesis of K/T impact spherules - from Haiti to Wyoming and beyond

    USGS Publications Warehouse

    Bohor, B.F.; Glass, B.P.

    1995-01-01

    Impact spherules in Cretaceous/Tertiary (K/T) boundary clays and claystones consist of two types; each type is confined to its own separate layer of the boundary couplet in the Western Hemisphere. The form and composition of each of the spherule types result from its own unique mode of origin during the K/T event. Type 1 splash-form spherules occur only in the melt-ejecta (basal) layer of the K/T couplet. This layer was deposited from a ballistic ejecta curtain composed of melt-glass droplets transported mostly within the atmosphere. In contrast, Type 2 spherules are accreted, partially crystalline, spheroidal bodies that formed by condensation of vaporized bolide and target-rock materials in an expanding fireball cloud, from which they settled out of buoyant suspension to form the fireball layer. Dendritic and skeletal Ni-rich spinel crystals are unique to these Type 2 spherules in the fireball layer. -from Authors

  2. Geochemistry of polymict ureilite EET83309, and a partially-disruptive impact model for ureilite origin

    NASA Technical Reports Server (NTRS)

    Warren, Paul H.; Kallemeyn, Gregory W.

    1989-01-01

    Bulk-compositional data for the EET83309 polymict ureilite were obtained using INAA and radiochemistry procedures and electron probe analysis. It was found that the EET83309 has a bulk composition indistinguishable from ordinary ('monomict') ureilites for all elements except light-middle REEs (which are present in much higher concentrations), suggesting that polymict ureilites are mixtures of ordinary ureilites which were mixed on a very small number of parent bodies. Despite the light-REE enrichments, polymict ureilites are nearly devoid of basaltic (Al-rich) material. It is suggested that the missing basalt may have been blown off the parent body by a partially disruptive collision with a large C-rich projectile. This impact model of ureilite origin reconciles many paradoxical aspects of ureilite composition.

  3. Potassium isotopic evidence for a high-energy giant impact origin of the Moon

    NASA Astrophysics Data System (ADS)

    Wang, Kun; Jacobsen, Stein B.

    2016-10-01

    The Earth–Moon system has unique chemical and isotopic signatures compared with other planetary bodies; any successful model for the origin of this system therefore has to satisfy these chemical and isotopic constraints. The Moon is substantially depleted in volatile elements such as potassium compared with the Earth and the bulk solar composition, and it has long been thought to be the result of a catastrophic Moon-forming giant impact event. Volatile-element-depleted bodies such as the Moon were expected to be enriched in heavy potassium isotopes during the loss of volatiles; however such enrichment was never found. Here we report new high-precision potassium isotope data for the Earth, the Moon and chondritic meteorites. We found that the lunar rocks are significantly (>2σ) enriched in the heavy isotopes of potassium compared to the Earth and chondrites (by around 0.4 parts per thousand). The enrichment of the heavy isotope of potassium in lunar rocks compared with those of the Earth and chondrites can be best explained as the result of the incomplete condensation of a bulk silicate Earth vapour at an ambient pressure that is higher than 10 bar. We used these coupled constraints of the chemical loss and isotopic fractionation of K to compare two recent dynamic models that were used to explain the identical non-mass-dependent isotope composition of the Earth and the Moon. Our K isotope result is inconsistent with the low-energy disk equilibration model, but supports the high-energy, high-angular-momentum giant impact model for the origin of the Moon. High-precision potassium isotope data can also be used as a ‘palaeo-barometer’ to reveal the physical conditions during the Moon-forming event.

  4. Origin, functional role, and clinical impact of Fanconi anemia FANCA mutations

    PubMed Central

    Castella, Maria; Pujol, Roser; Callén, Elsa; Trujillo, Juan P.; Casado, José A.; Gille, Hans; Lach, Francis P.; Auerbach, Arleen D.; Schindler, Detlev; Benítez, Javier; Porto, Beatriz; Ferro, Teresa; Muñoz, Arturo; Sevilla, Julián; Madero, Luis; Cela, Elena; Beléndez, Cristina; de Heredia, Cristina Díaz; Olivé, Teresa; de Toledo, José Sánchez; Badell, Isabel; Torrent, Montserrat; Estella, Jesús; Dasí, Ángeles; Rodríguez-Villa, Antonia; Gómez, Pedro; Barbot, José; Tapia, María; Molinés, Antonio; Figuera, Ángela; Bueren, Juan A.

    2011-01-01

    Fanconi anemia is characterized by congenital abnormalities, bone marrow failure, and cancer predisposition. To investigate the origin, functional role, and clinical impact of FANCA mutations, we determined a FANCA mutational spectrum with 130 pathogenic alleles. Some of these mutations were further characterized for their distribution in populations, mode of emergence, or functional consequences at cellular and clinical level. The world most frequent FANCA mutation is not the result of a mutational “hot-spot” but results from worldwide dissemination of an ancestral Indo-European mutation. We provide molecular evidence that total absence of FANCA in humans does not reduce embryonic viability, as the observed frequency of mutation carriers in the Gypsy population equals the expected by Hardy-Weinberg equilibrium. We also prove that long distance Alu-Alu recombination can cause Fanconi anemia by originating large interstitial deletions involving FANCA and 2 adjacent genes. Finally, we show that all missense mutations studied lead to an altered FANCA protein that is unable to relocate to the nucleus and activate the FA/BRCA pathway. This may explain the observed lack of correlation between type of FANCA mutation and cellular phenotype or clinical severity in terms of age of onset of hematologic disease or number of malformations. PMID:21273304

  5. A giant impact origin for Pluto's small moons and satellite multiplicity in the Kuiper belt.

    PubMed

    Stern, S A; Weaver, H A; Steffl, A J; Mutchler, M J; Merline, W J; Buie, M W; Young, E F; Young, L A; Spencer, J R

    2006-02-23

    The two newly discovered satellites of Pluto (P1 and P2) have masses that are small compared to both Pluto and Charon-that is, between 5 x 10(-4) and 1 x 10(-5) of Pluto's mass, and between 5 x 10(-3) and 1 x 10(-4) of Charon's mass. This discovery, combined with the constraints on the absence of more distant satellites of Pluto, reveal that Pluto and its moons comprise an unusual, highly compact, quadruple system. These facts naturally raise the question of how this puzzling satellite system came to be. Here we show that P1 and P2's proximity to Pluto and Charon, the fact that P1 and P2 are on near-circular orbits in the same plane as Pluto's large satellite Charon, along with their apparent locations in or near high-order mean-motion resonances, all probably result from their being constructed from collisional ejecta that originated from the Pluto-Charon formation event. We also argue that dust-ice rings of variable optical depths form sporadically in the Pluto system, and that rich satellite systems may be found--perhaps frequently--around other large Kuiper belt objects. PMID:16495992

  6. A giant impact origin for Pluto's small moons and satellite multiplicity in the Kuiper belt

    NASA Astrophysics Data System (ADS)

    Stern, S. A.; Weaver, H. A.; Steffl, A. J.; Mutchler, M. J.; Merline, W. J.; Buie, M. W.; Young, E. F.; Young, L. A.; Spencer, J. R.

    2006-02-01

    The two newly discovered satellites of Pluto (P1 and P2) have masses that are small compared to both Pluto and Charon-that is, between 5 × 10-4 and 1 × 10-5 of Pluto's mass, and between 5 × 10-3 and 1 × 10-4 of Charon's mass. This discovery, combined with the constraints on the absence of more distant satellites of Pluto, reveal that Pluto and its moons comprise an unusual, highly compact, quadruple system. These facts naturally raise the question of how this puzzling satellite system came to be. Here we show that P1 and P2's proximity to Pluto and Charon, the fact that P1 and P2 are on near-circular orbits in the same plane as Pluto's large satellite Charon, along with their apparent locations in or near high-order mean-motion resonances, all probably result from their being constructed from collisional ejecta that originated from the Pluto-Charon formation event. We also argue that dust-ice rings of variable optical depths form sporadically in the Pluto system, and that rich satellite systems may be found-perhaps frequently-around other large Kuiper belt objects.

  7. A giant impact origin for Pluto's small moons and satellite multiplicity in the Kuiper belt.

    PubMed

    Stern, S A; Weaver, H A; Steffl, A J; Mutchler, M J; Merline, W J; Buie, M W; Young, E F; Young, L A; Spencer, J R

    2006-02-23

    The two newly discovered satellites of Pluto (P1 and P2) have masses that are small compared to both Pluto and Charon-that is, between 5 x 10(-4) and 1 x 10(-5) of Pluto's mass, and between 5 x 10(-3) and 1 x 10(-4) of Charon's mass. This discovery, combined with the constraints on the absence of more distant satellites of Pluto, reveal that Pluto and its moons comprise an unusual, highly compact, quadruple system. These facts naturally raise the question of how this puzzling satellite system came to be. Here we show that P1 and P2's proximity to Pluto and Charon, the fact that P1 and P2 are on near-circular orbits in the same plane as Pluto's large satellite Charon, along with their apparent locations in or near high-order mean-motion resonances, all probably result from their being constructed from collisional ejecta that originated from the Pluto-Charon formation event. We also argue that dust-ice rings of variable optical depths form sporadically in the Pluto system, and that rich satellite systems may be found--perhaps frequently--around other large Kuiper belt objects.

  8. An investigation into the impact of question structure on the performance of first year physics undergraduate students at the University of Cambridge

    NASA Astrophysics Data System (ADS)

    Gibson, Valerie; Jardine-Wright, Lisa; Bateman, Elizabeth

    2015-07-01

    We describe a study of the impact of exam question structure on the performance of first year Natural Sciences physics undergraduates from the University of Cambridge. The results show conclusively that a student’s performance improves when questions are scaffolded compared with university style questions. In a group of 77 female students we observe that the average exam mark increases by 13.4% for scaffolded questions, which corresponds to a 4.9 standard deviation effect. The equivalent observation for 236 male students is 9% (5.5 standard deviations). We also observe a correlation between exam performance and A2-level marks for UK students, and that students who receive their school education overseas, in a mixed gender environment, or at an independent school are more likely to receive a first class mark in the exam. These results suggest a mis-match between the problem-solving skills and assessment procedures between school and first year university and will provide key input into the future teaching and assessment of first year undergraduate physics students.

  9. Lunar dark-haloed impact craters - Origin and implications for early mare volcanism

    NASA Technical Reports Server (NTRS)

    Bell, J. F.; Hawke, B. R.

    1984-01-01

    Spectral, thermal, radar, and photogeologic data were used to determine the composition and origin of lunar dark-haloed craters. Analyses of reflectance spectra (near-infrared) of dark-haloed craters on light plains indicate that in every instance these craters exposed mare basalts which had previously been covered by varying thicknesses of highlands debris. In the Schiller-Schickard region a relatively thick highlands unit was emplaced as a result of the Orientale impact event. The results of recent remote sensing photogeologic and lunar samples studies indicate that mare volcanism was a significant process during much of the pre-Imbrian epoch and may have been initiated as early as 4.2-4.3 Ga. The very early volcanic episodes contributed materials to the lunar surface which were later incorporated into the upper portion of the highlands crust by subsequent impact mixing. On the basis of the data it is concluded that current models of the extent and duration of mare volcanisms, as well as those involving the composition of thermal evolution of the lunar interior will have to be revised.

  10. Domestication and early agriculture in the Mediterranean Basin: Origins, diffusion, and impact.

    PubMed

    Zeder, Melinda A

    2008-08-19

    The past decade has witnessed a quantum leap in our understanding of the origins, diffusion, and impact of early agriculture in the Mediterranean Basin. In large measure these advances are attributable to new methods for documenting domestication in plants and animals. The initial steps toward plant and animal domestication in the Eastern Mediterranean can now be pushed back to the 12th millennium cal B.P. Evidence for herd management and crop cultivation appears at least 1,000 years earlier than the morphological changes traditionally used to document domestication. Different species seem to have been domesticated in different parts of the Fertile Crescent, with genetic analyses detecting multiple domestic lineages for each species. Recent evidence suggests that the expansion of domesticates and agricultural economies across the Mediterranean was accomplished by several waves of seafaring colonists who established coastal farming enclaves around the Mediterranean Basin. This process also involved the adoption of domesticates and domestic technologies by indigenous populations and the local domestication of some endemic species. Human environmental impacts are seen in the complete replacement of endemic island faunas by imported mainland fauna and in today's anthropogenic, but threatened, Mediterranean landscapes where sustainable agricultural practices have helped maintain high biodiversity since the Neolithic. PMID:18697943

  11. Origin and impact of recombination via charge transfer excitons in polymer/fullerene solar cells

    NASA Astrophysics Data System (ADS)

    Hallermann, Markus; da Como, Enrico; Feldmann, Jochen

    2010-03-01

    To further advance the performances of organic photovoltaic cells a thorough understanding of loss mechanisms in polymer/fullerene blends is mandatory. Recombination via charge transfer excitons (CTEs) appears to be a fundamental loss, potentially impacting the open circuit voltage (VOC) and the short circuit current (ISC) of cells. We unravel the origin of CTEs forming in polymer/fullerene blends and discuss their importance in recombination processes considering binding energy [1], polymer conformation [2], and energetic position. CTE photoluminescence (PL) is observed in material combinations such as P3HT and PPV blended with fullerene acceptors. By combining electron microscopy and PL spectroscopy, we show that CTE recombination is only slightly influenced by the mesoscopic morphology, whereas strongly by the polymer chain conformation [2]. By shifting the orbital energies of the fullerene, we tune the CTE PL characteristics. High energy CTE emission results in cells with a beneficial increase in VOC. On the other hand, high energy CTE emission leads to a more efficient recombination impacting directly the ISC. The results highlight a fundamental limit in the efficiency of organic solar cells with CTE recombination. [1] Hallermann et al. APL 2008 [2] Hallermann et al. AFM 2009

  12. Domestication and early agriculture in the Mediterranean Basin: Origins, diffusion, and impact.

    PubMed

    Zeder, Melinda A

    2008-08-19

    The past decade has witnessed a quantum leap in our understanding of the origins, diffusion, and impact of early agriculture in the Mediterranean Basin. In large measure these advances are attributable to new methods for documenting domestication in plants and animals. The initial steps toward plant and animal domestication in the Eastern Mediterranean can now be pushed back to the 12th millennium cal B.P. Evidence for herd management and crop cultivation appears at least 1,000 years earlier than the morphological changes traditionally used to document domestication. Different species seem to have been domesticated in different parts of the Fertile Crescent, with genetic analyses detecting multiple domestic lineages for each species. Recent evidence suggests that the expansion of domesticates and agricultural economies across the Mediterranean was accomplished by several waves of seafaring colonists who established coastal farming enclaves around the Mediterranean Basin. This process also involved the adoption of domesticates and domestic technologies by indigenous populations and the local domestication of some endemic species. Human environmental impacts are seen in the complete replacement of endemic island faunas by imported mainland fauna and in today's anthropogenic, but threatened, Mediterranean landscapes where sustainable agricultural practices have helped maintain high biodiversity since the Neolithic.

  13. Domestication and early agriculture in the Mediterranean Basin: Origins, diffusion, and impact

    PubMed Central

    Zeder, Melinda A.

    2008-01-01

    The past decade has witnessed a quantum leap in our understanding of the origins, diffusion, and impact of early agriculture in the Mediterranean Basin. In large measure these advances are attributable to new methods for documenting domestication in plants and animals. The initial steps toward plant and animal domestication in the Eastern Mediterranean can now be pushed back to the 12th millennium cal B.P. Evidence for herd management and crop cultivation appears at least 1,000 years earlier than the morphological changes traditionally used to document domestication. Different species seem to have been domesticated in different parts of the Fertile Crescent, with genetic analyses detecting multiple domestic lineages for each species. Recent evidence suggests that the expansion of domesticates and agricultural economies across the Mediterranean was accomplished by several waves of seafaring colonists who established coastal farming enclaves around the Mediterranean Basin. This process also involved the adoption of domesticates and domestic technologies by indigenous populations and the local domestication of some endemic species. Human environmental impacts are seen in the complete replacement of endemic island faunas by imported mainland fauna and in today's anthropogenic, but threatened, Mediterranean landscapes where sustainable agricultural practices have helped maintain high biodiversity since the Neolithic. PMID:18697943

  14. A symbiotic view of the origin of life at hydrothermal impact crater-lakes.

    PubMed

    Chatterjee, Sankar

    2016-07-27

    Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. The theory suffers from the 'concentration problem' of cosmic and terrestrial biomolecules because of the vastness of the Eoarchean global ocean. An attractive alternative site would be highly sequestered, small, hydrothermal crater-lakes that might have cradled life on early Earth. A new symbiotic model for the origin of life at hydrothermal crater-lakes is proposed here. Meteoritic impacts on the Eoarchean crust at the tail end of the Heavy Bombardment period might have played important roles in the origin of life. Impacts and collisions that created hydrothermal crater lakes on the Eoarchean crust inadvertently became the perfect crucibles for prebiotic chemistry with building blocks of life, which ultimately led to the first organisms by prebiotic synthesis. In this scenario, life arose through four hierarchical stages of increasing molecular complexity in multiple niches of crater basins. In the cosmic stage (≥4.6 Ga), the building blocks of life had their beginnings in the interstellar space during the explosion of a nearby star. Both comets and carbonaceous chondrites delivered building blocks of life and ice to early Earth, which were accumulated in hydrothermal impact crater-lakes. In the geologic stage (∼4 Ga), crater basins contained an assortment of cosmic and terrestrial organic compounds, powered by hydrothermal, solar, tidal, and chemical energies, which drove the prebiotic synthesis. At the water surface, self-assembled primitive lipid membranes floated as a thick oil slick. Archean Greenstone belts in Greenland, Australia, and South Africa possibly represent the relics of these Archean craters, where the oldest fossils of thermophilic life (∼3.5 Ga) have been detected. In the chemical stage, monomers such as nucleotides and amino acids were selected from random assemblies of the prebiotic soup; they were

  15. A symbiotic view of the origin of life at hydrothermal impact crater-lakes.

    PubMed

    Chatterjee, Sankar

    2016-07-27

    Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. The theory suffers from the 'concentration problem' of cosmic and terrestrial biomolecules because of the vastness of the Eoarchean global ocean. An attractive alternative site would be highly sequestered, small, hydrothermal crater-lakes that might have cradled life on early Earth. A new symbiotic model for the origin of life at hydrothermal crater-lakes is proposed here. Meteoritic impacts on the Eoarchean crust at the tail end of the Heavy Bombardment period might have played important roles in the origin of life. Impacts and collisions that created hydrothermal crater lakes on the Eoarchean crust inadvertently became the perfect crucibles for prebiotic chemistry with building blocks of life, which ultimately led to the first organisms by prebiotic synthesis. In this scenario, life arose through four hierarchical stages of increasing molecular complexity in multiple niches of crater basins. In the cosmic stage (≥4.6 Ga), the building blocks of life had their beginnings in the interstellar space during the explosion of a nearby star. Both comets and carbonaceous chondrites delivered building blocks of life and ice to early Earth, which were accumulated in hydrothermal impact crater-lakes. In the geologic stage (∼4 Ga), crater basins contained an assortment of cosmic and terrestrial organic compounds, powered by hydrothermal, solar, tidal, and chemical energies, which drove the prebiotic synthesis. At the water surface, self-assembled primitive lipid membranes floated as a thick oil slick. Archean Greenstone belts in Greenland, Australia, and South Africa possibly represent the relics of these Archean craters, where the oldest fossils of thermophilic life (∼3.5 Ga) have been detected. In the chemical stage, monomers such as nucleotides and amino acids were selected from random assemblies of the prebiotic soup; they were

  16. Does Plant Origin Influence the Fitness Impact of Flower Damage? A Meta-Analysis.

    PubMed

    González-Browne, Catalina; Murúa, Maureen M; Navarro, Luis; Medel, Rodrigo

    2016-01-01

    Herbivory has been long considered an important component of plant-animal interactions that influences the success of invasive species in novel habitats. One of the most important hypotheses linking herbivory and invasion processes is the enemy-release hypothesis, in which exotic plants are hypothesized to suffer less herbivory and fitness-costs in their novel ranges as they leave behind their enemies in the original range. Most evidence, however, comes from studies on leaf herbivory, and the importance of flower herbivory for the invasion process remains largely unknown. Here we present the results of a meta-analysis of the impact of flower herbivory on plant reproductive success, using as moderators the type of damage caused by floral herbivores and the residence status of the plant species. We found 51 papers that fulfilled our criteria. We also included 60 records from unpublished data of the laboratory, gathering a total of 143 case studies. The effects of florivory and nectar robbing were both negative on plant fitness. The methodology employed in studies of flower herbivory influenced substantially the outcome of flower damage. Experiments using natural herbivory imposed a higher fitness cost than simulated herbivory, such as clipping and petal removal, indicating that studies using artificial herbivory as surrogates of natural herbivory underestimate the real fitness impact of flower herbivory. Although the fitness cost of floral herbivory was high both in native and exotic plant species, floral herbivores had a three-fold stronger fitness impact on exotic than native plants, contravening a critical element of the enemy-release hypothesis. Our results suggest a critical but largely unrecognized role of floral herbivores in preventing the spread of introduced species into newly colonized areas.

  17. Does Plant Origin Influence the Fitness Impact of Flower Damage? A Meta-Analysis.

    PubMed

    González-Browne, Catalina; Murúa, Maureen M; Navarro, Luis; Medel, Rodrigo

    2016-01-01

    Herbivory has been long considered an important component of plant-animal interactions that influences the success of invasive species in novel habitats. One of the most important hypotheses linking herbivory and invasion processes is the enemy-release hypothesis, in which exotic plants are hypothesized to suffer less herbivory and fitness-costs in their novel ranges as they leave behind their enemies in the original range. Most evidence, however, comes from studies on leaf herbivory, and the importance of flower herbivory for the invasion process remains largely unknown. Here we present the results of a meta-analysis of the impact of flower herbivory on plant reproductive success, using as moderators the type of damage caused by floral herbivores and the residence status of the plant species. We found 51 papers that fulfilled our criteria. We also included 60 records from unpublished data of the laboratory, gathering a total of 143 case studies. The effects of florivory and nectar robbing were both negative on plant fitness. The methodology employed in studies of flower herbivory influenced substantially the outcome of flower damage. Experiments using natural herbivory imposed a higher fitness cost than simulated herbivory, such as clipping and petal removal, indicating that studies using artificial herbivory as surrogates of natural herbivory underestimate the real fitness impact of flower herbivory. Although the fitness cost of floral herbivory was high both in native and exotic plant species, floral herbivores had a three-fold stronger fitness impact on exotic than native plants, contravening a critical element of the enemy-release hypothesis. Our results suggest a critical but largely unrecognized role of floral herbivores in preventing the spread of introduced species into newly colonized areas. PMID:26785039

  18. Does Plant Origin Influence the Fitness Impact of Flower Damage? A Meta-Analysis

    PubMed Central

    González-Browne, Catalina; Murúa, Maureen M.; Navarro, Luis; Medel, Rodrigo

    2016-01-01

    Herbivory has been long considered an important component of plant-animal interactions that influences the success of invasive species in novel habitats. One of the most important hypotheses linking herbivory and invasion processes is the enemy-release hypothesis, in which exotic plants are hypothesized to suffer less herbivory and fitness-costs in their novel ranges as they leave behind their enemies in the original range. Most evidence, however, comes from studies on leaf herbivory, and the importance of flower herbivory for the invasion process remains largely unknown. Here we present the results of a meta-analysis of the impact of flower herbivory on plant reproductive success, using as moderators the type of damage caused by floral herbivores and the residence status of the plant species. We found 51 papers that fulfilled our criteria. We also included 60 records from unpublished data of the laboratory, gathering a total of 143 case studies. The effects of florivory and nectar robbing were both negative on plant fitness. The methodology employed in studies of flower herbivory influenced substantially the outcome of flower damage. Experiments using natural herbivory imposed a higher fitness cost than simulated herbivory, such as clipping and petal removal, indicating that studies using artificial herbivory as surrogates of natural herbivory underestimate the real fitness impact of flower herbivory. Although the fitness cost of floral herbivory was high both in native and exotic plant species, floral herbivores had a three-fold stronger fitness impact on exotic than native plants, contravening a critical element of the enemy-release hypothesis. Our results suggest a critical but largely unrecognized role of floral herbivores in preventing the spread of introduced species into newly colonized areas. PMID:26785039

  19. Assessing the Impact of De Novo Social Ties within Health Intervention Settings: New Questions for Health Behavior Intervention Research.

    PubMed

    Tesdahl, Eric; Gesell, Sabina B

    2015-12-01

    Recent developments in the study of health and social networks have focused on linkages between health outcomes and naturally occurring social relations, such as friendship or kinship. Based on findings in this area, a new generation of health behavior intervention programs have been implemented that rely on the formation of new social relations among program participants. However, little is known about the qualities of these de novo social relations. We examined the social networks of 59 participants within a randomized controlled trial of an intervention designed to prevent excessive gestational weight gain. We employed exponential random graph modeling techniques to analyze supportive relationships formed between participants in the intervention arm, to detect unique effects of program participation on the likelihood of forming ties. Program participation had a positive effect on the likelihood of forming supportive social relations, however, in this particular timeframe we did not detect any additional effect of such relations on the health behaviors or outcomes of interest. Our findings raise two critical questions: do short-term group-level programs reliably lead to the formation of new social relations among participants; and do these relations have a unique effect on health outcomes relative to standard methods of health behavior intervention? PMID:26577514

  20. Assessing the Impact of De Novo Social Ties within Health Intervention Settings: New Questions for Health Behavior Intervention Research.

    PubMed

    Tesdahl, Eric; Gesell, Sabina B

    2015-12-01

    Recent developments in the study of health and social networks have focused on linkages between health outcomes and naturally occurring social relations, such as friendship or kinship. Based on findings in this area, a new generation of health behavior intervention programs have been implemented that rely on the formation of new social relations among program participants. However, little is known about the qualities of these de novo social relations. We examined the social networks of 59 participants within a randomized controlled trial of an intervention designed to prevent excessive gestational weight gain. We employed exponential random graph modeling techniques to analyze supportive relationships formed between participants in the intervention arm, to detect unique effects of program participation on the likelihood of forming ties. Program participation had a positive effect on the likelihood of forming supportive social relations, however, in this particular timeframe we did not detect any additional effect of such relations on the health behaviors or outcomes of interest. Our findings raise two critical questions: do short-term group-level programs reliably lead to the formation of new social relations among participants; and do these relations have a unique effect on health outcomes relative to standard methods of health behavior intervention?

  1. Snow-avalanche impact landforms in Breheimen, southern Norway: Origin, age, and paleoclimatic implications

    SciTech Connect

    Matthews, J.A.; McCarroll, D. )

    1994-05-01

    Twelve snow-avalanche ramparts in Jostedalen and Sprongdalen (Breheimen, southern Norway) are investigated to elucidate processes of formation, the history of avalanche activity, and their potential for paleoclimatic reconstruction. Variation in the form of these riverbank boulder ramparts reflects local patterns of avalanche impact. Differences in clast roundness between ramparts, avalanche tracks, and river beds indicate that, on average, 50 to 60% of the clasts in the ramparts originate from river bedload as opposed to avalanche source areas or tracks. Rampart clasts increase in roundness downstream over a distance of 12 km, and the contribution from the river bed varies from 26 to 80% depending on local factors. Conventional lichenometric dating suggests ages for the initiation of rampart formation of 250 to 2000 yr, but they probably have a much longer history. Lichen-size frequency distributions, using the largest lichen from each of n boulders, reflect the age-frequency of surface boulders, providing a record of late Holocene avalanche activity. A simulation model suggests that maximum avalanche activity affected nine of the ramparts during the 19th century, after the peak of the Little Ice Age. The pattern of avalanche activity differs from the pattern of glacier variations but is in close agreement with that of debris-flow activity. The ramparts may yield a valuable proxy record of winter snowfall. 48 refs., 12 figs., 4 tabs.

  2. Recruitment: Some Unanswered Questions

    ERIC Educational Resources Information Center

    Ericson, Robert W.

    1974-01-01

    The author summarizes various past studies on job recruitment methods and raises further unanswered questions, especially important to policy-makers, pertaining to the: (1) impact on employers, workers, and society; (2) level of sophistication of employer recruitment method selection; (3) major factors influencing a recruitment selection method;…

  3. On the origin of superparamagnetic minerals of tropical soils and their impact on landmine detection

    NASA Astrophysics Data System (ADS)

    Igel, Jan; Preetz, Holger; Altfelder, Sven

    2010-05-01

    Magnetic susceptibility of soils is mainly determined by their content of ferrimagnetic minerals whereas titanomagnetite, magnetite and maghemite being the most important ones. Titanomagnetite and magnetite are of magmatic origin, i.e. they crystallise during cooling of iron-rich magma and are part of many igneous rocks. Maghemite and sometimes magnetite are of pedogenic origin. They develop by crystallisation of dissolved iron during soil forming processes. Ferrimagnetic minerals that are smaller than some tens of nanometres are superparamagnetic (SP) and show frequency dependent susceptibility. SP minerals crystallise if magma cools down rapidly (e.g. volcanic magmas, glasses and ashes) and are frequently formed during pedogenesis. In order to investigate the origin and formation of SP minerals in tropical soils, we analyse magnetic properties of 594 samples from the entire tropics comprising the whole range of weathering states from unweathered rock to highly weathered soil. Tropical soils are subject to intense chemical weathering and are rich in ferrimagnetic and in particular SP minerals. The process leading to a high content of these minerals is either residual enrichment due to their weathering resistance or neo-formation. In this study we focus on the frequency dependent susceptibility (absolute and relative) of the samples and classify it according to the parent material and alteration. We observe that • within each parent-material group, rock material shows in general lower susceptibility and absolute frequency dependence than soil material • ultrabasic and basic/intermediate rocks and soils developed from these rocks show high absolute frequency dependent susceptibility and, in contrast, acid rocks and sediments show lower absolute frequency dependence • absolute frequency dependence increases from unweathered rock to weathered rock, and from subsoil to topsoil material within every group of parent material • relative frequency dependence rises

  4. False alarms and missed events: the impact and origins of perceived inaccuracy in tornado warning systems.

    PubMed

    Ripberger, Joseph T; Silva, Carol L; Jenkins-Smith, Hank C; Carlson, Deven E; James, Mark; Herron, Kerry G

    2015-01-01

    Theory and conventional wisdom suggest that errors undermine the credibility of tornado warning systems and thus decrease the probability that individuals will comply (i.e., engage in protective action) when future warnings are issued. Unfortunately, empirical research on the influence of warning system accuracy on public responses to tornado warnings is incomplete and inconclusive. This study adds to existing research by analyzing two sets of relationships. First, we assess the relationship between perceptions of accuracy, credibility, and warning response. Using data collected via a large regional survey, we find that trust in the National Weather Service (NWS; the agency responsible for issuing tornado warnings) increases the likelihood that an individual will opt for protective action when responding to a hypothetical warning. More importantly, we find that subjective perceptions of warning system accuracy are, as theory suggests, systematically related to trust in the NWS and (by extension) stated responses to future warnings. The second half of the study matches survey data against NWS warning and event archives to investigate a critical follow-up question--Why do some people perceive that their warning system is accurate, whereas others perceive that their system is error prone? We find that subjective perceptions are--in part-a function of objective experience, knowledge, and demographic characteristics. When considered in tandem, these findings support the proposition that errors influence perceptions about the accuracy of warning systems, which in turn impact the credibility that people assign to information provided by systems and, ultimately, public decisions about how to respond when warnings are issued.

  5. False alarms and missed events: the impact and origins of perceived inaccuracy in tornado warning systems.

    PubMed

    Ripberger, Joseph T; Silva, Carol L; Jenkins-Smith, Hank C; Carlson, Deven E; James, Mark; Herron, Kerry G

    2015-01-01

    Theory and conventional wisdom suggest that errors undermine the credibility of tornado warning systems and thus decrease the probability that individuals will comply (i.e., engage in protective action) when future warnings are issued. Unfortunately, empirical research on the influence of warning system accuracy on public responses to tornado warnings is incomplete and inconclusive. This study adds to existing research by analyzing two sets of relationships. First, we assess the relationship between perceptions of accuracy, credibility, and warning response. Using data collected via a large regional survey, we find that trust in the National Weather Service (NWS; the agency responsible for issuing tornado warnings) increases the likelihood that an individual will opt for protective action when responding to a hypothetical warning. More importantly, we find that subjective perceptions of warning system accuracy are, as theory suggests, systematically related to trust in the NWS and (by extension) stated responses to future warnings. The second half of the study matches survey data against NWS warning and event archives to investigate a critical follow-up question--Why do some people perceive that their warning system is accurate, whereas others perceive that their system is error prone? We find that subjective perceptions are--in part-a function of objective experience, knowledge, and demographic characteristics. When considered in tandem, these findings support the proposition that errors influence perceptions about the accuracy of warning systems, which in turn impact the credibility that people assign to information provided by systems and, ultimately, public decisions about how to respond when warnings are issued. PMID:25082540

  6. 'A question of balance': addressing the public health impacts of multinational enterprises in the OECD Guidelines for Multinational Enterprises.

    PubMed

    Yang, Joshua S; McDaniel, Patricia A; Malone, Ruth E

    2012-01-01

    The global community is beginning to address non-communicable diseases, but how to increase the accountability of multinational enterprises (MNEs) for the health impacts of their products and practices remains unclear. We examine the Organization for Economic Cooperation and Development's (OECD) efforts to do so through voluntary MNE guidelines. We developed a historical case study of how the OECD Guidelines for Multinational Enterprises were developed and revised from 1973 to 2000 through an analysis of publicly available archived OECD and tobacco industry documents. The first edition of the Guidelines was a purely economic instrument. Outside pressures and a desire to ward off more stringent regulatory efforts resulted in the addition over time of guidelines related to the environment, consumer interests, sustainable development and human rights. Despite their voluntary nature, the Guidelines can play a role in efforts to help balance the interests of MNEs and public health by providing a starting point for efforts to create binding provisions addressing MNEs' contributions to disease burden or disease reduction. PMID:23046298

  7. Tektite origin by hypervelocity asteroidal or cometary impact: The quest for the source craters

    NASA Technical Reports Server (NTRS)

    Koeberl, Christian

    1992-01-01

    Tektites are natural glasses that are chemically homogeneous, often spherically symmetrical objects several centimeters in size, and occur in four known strewn fields on the surface of the Earth: the North American, moldavite (or Central European), Ivory Coast, and Australasian strewn fields. Tektites found within such strewn fields are related to each other with respect to their petrological, physical, and chemical properties as well as their age. A theory of tektite origin needs to explain the similarity of tektites in respect to age and certain aspects of isotopic and chemical composition within one strewn field, as well as the variety of tektite materials present in each strewn field. In addition to tektites on land, microtektites (which are generally less than 1 mm in diameter) have been found in deep-sea cores. Tektites are classified into three groups: (1) normal or splash-form tektites, (2) aerodynamically shaped tektites, and (3) Muong Nong-type tektites (sometimes also called layered tektites). The aerodynamic ablation results from partial remelting of glass during atmospheric passage after it was ejected outside the terrestrial atmosphere and quenched from a hot liquid. Aerodynamically shaped tektites are known mainly from the Australasian strewn field where they occur as flanged-button australites. The shapes of splash-form tektites (spheres, droplets, teardrops, dumbbells, etc., or fragments thereof) are the result of the solidification of rotating liquids in the air or vacuum. Mainly due to chemical studies, it is now commonly accepted that tektites are the product of melting and quenching of terrestrial rocks during hypervelocity impact on the Earth. The chemistry of tektites is in many respects identical to the composition of upper crustal material.

  8. The Impact of Origin and Host Country Schooling on the Economic Performance of Immigrants

    ERIC Educational Resources Information Center

    Kanas, Agnieszka; van Tubergen, Frank

    2009-01-01

    This study examines the economic returns to schooling acquired in the country of origin and the country of destination. It uses large-scale survey data on Turkish, Moroccan, Surinamese and Antillean immigrants in the Netherlands, which contain direct measures of pre- and post migration schooling. It is studied whether the returns to origin-country…

  9. A decadal satellite analysis of the origins and impacts of smoke in Colorado

    NASA Astrophysics Data System (ADS)

    Martin, M. Val; Heald, C. L.; Ford, B.; Prenni, A. J.; Wiedinmyer, C.

    2013-08-01

    We analyze the record of aerosol optical depth (AOD) measured by the MODerate resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite in combination with surface PM2.5 to investigate the impact of fires on aerosol loading and air quality over Colorado from 2000 to 2012, and to evaluate the contribution of local versus transported smoke. Fire smoke contributed significantly to the AOD levels observed over Colorado. During the worst fire seasons of 2002 and 2012, average MODIS AOD over the Colorado Front Range corridor were 20-50% larger than the other 11 yr studied. Surface PM2.5 was also unusually elevated during fire events and concentrations were in many occasions above the daily National Ambient Air Quality Standard (35 μg m-3) and even reached locally unhealthy levels (> 100 μg m-3) over populated areas during the 2012 High Park fire and the 2002 Hayman fire. Over the 13 yr examined, long-range transport of smoke from northwestern US and even California (> 1500 km distance) occurred often and affected AOD and surface PM2.5. During most of the transport events, MODIS AOD and surface PM2.5 were reasonable correlated (r2 = 0.2-0.9), indicating that smoke subsided into the Colorado boundary layer and reached surface levels. However, that is not always the case since at least one event of AOD enhancement was disconnected from the surface (r2<0.01 and low PM2.5 levels). Observed plume heights from the Multi-angle Imaging SpectroRadiometer (MISR) satellite instrument and vertical aerosol profiles measured by the space-based Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) showed a complex vertical distribution of smoke emitted by the High Park fire in 2012. Smoke was detected from a range of 1.5 to 7.5 km altitude at the fire origin and from ground levels to 12.3 km altitude far away from the source. The variability of smoke altitude as well as the local meteorology were key in determining the aerosol loading and air quality over the

  10. A decadal satellite analysis of the origins and impacts of smoke in Colorado

    NASA Astrophysics Data System (ADS)

    Martin, M. Val; Heald, C. L.; Ford, B.; Prenni, A. J.; Wiedinmyer, C.

    2013-03-01

    We analyze the record of aerosol optical depth (AOD) measured by the MODerate resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite in combination with surface PM2.5 to investigate the impact of fires on aerosol loading and air quality over Colorado from 2000 to 2012, and to evaluate the contribution of local versus transported smoke. Fire smoke contributed significantly to the AOD levels observed over Colorado. During the worst fire seasons of 2002 and 2012, average MODIS AOD over the Colorado Front Range corridor were 20-50% larger than the other 11 yr studied. Surface PM2.5 was also unusually elevated during fire events and concentrations were in many occasions above the daily National Ambient Air Quality Standard (35 μg m-3) and even reached locally unhealthy levels (> 100 μg m-3) over populated areas during the 2012 High Park fire and the 2002 Hayman fire. Over the 13 yr examined, long-range transport of smoke from northwestern US and even California (>1500 km distance) occurred often and affected AOD and surface PM2.5. During most of the transport events, MODIS AOD and surface PM2.5 were reasonable correlated (r2 = 0.2-0.9), indicating that smoke subsided into the Colorado boundary layer and reached surface levels. However, that is not always the case since at least one event of AOD enhancement was disconnected from the surface (r2<0.01 and low PM2.5 levels). Observed plume heights from the Multi-angle Imaging SpectroRadiometer (MISR) satellite instrument and vertical aerosol profiles measured by the space-based Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) showed a complex vertical distribution of smoke emitted by the High Park fire in 2012. Smoke was detected from a range of 1.5 to 7.5 km altitude at the fire origin and from ground levels to 12.3 km altitude far away from the source. The variability of smoke altitude as well as the local meteorology were key in determining the aerosol loading and air quality over the Colorado

  11. Origins and Impacts of Arctic Soot: A GISS ModelE Experiment

    NASA Astrophysics Data System (ADS)

    Koch, D.; Hansen, J.

    2004-12-01

    The fragile Arctic is especially susceptible to the impacts of particles and other pollution. These may affect the radiative balance there, shifting temperature profiles, clouds and precipitation. Absorbing particles such as black carbon or soot may accelerate ice and snow melting. Studies of Arctic pollution typically implicate northern Eurasia, primarily Russia and Europe, as the primary sources of emissions that reach the Arctic. However, the predominant global source of industrial black carbon emissions is estimated to come from the Far East (20%). Another substantial but distant emission is from low latitude biomass burning (50%). We use the Goddard Institute for Space Studies (GISS) General Circulation Model (GCM) to investigate the origins of Arctic black carbon (BC) by isolating various source regions and types. We permit the BC to affect the model ice/snow albedo. The model suggests that the predominant sources of Arctic soot today are indeed these distant regions. The model's Arctic BC optical thickness is mostly from the Far East (30%) and from biomass (28%, with slightly more than 1/2 coming from north of 40N); North America, Russia and Europe each contribute 10-15%. Transport from the Far East and distant biomass regions involves lofting of BC aerosols to high altitudes where they may be transported pole-ward. Thus it differs from the classic `low altitude, winter-springtime Arctic haze' transport, presently believed to be the primary mechanism responsible for bringing pollution to the Arctic. The model does confirm the importance of Russian and European contributions to the low-altitude springtime Arctic haze transport, however it indicates that the Far East also contributes substantially (all 3 regions contribute 20-25%). In the Arctic upper troposphere/lower stratosphere during the springtime, we find that the Far East (30-50%) and low latitude biomass (20-30%) are dominant, with a significant aircraft contribution (10-20%). Substantial

  12. Mercurian volcanism questioned

    USGS Publications Warehouse

    Wilhelms, D.E.

    1976-01-01

    The Mariner 10 television team has argued that extensive plains on Mercury were formed by volcanism and compared them with the demonstrably lunar maria. I believe, however, that in stratigraphic relations, surface morphology, and albedo contrast, the Mercurian plains more closely resemble the lunar light plains. These lunar plains were interpreted as volcanic on the basis of data comparable to that available to the Mariner 10 investigators but have been shown by the Apollo missions to be of impact origin. The plains on Mercury might also be formed of impact materials, perhaps of impact melt or other basin ejecta that behaved more like a fluid when emplaced that did lunar basin ejecta. ?? 1976.

  13. Impact of Roasting on Identification of Hazelnut (Corylus avellana L.) Origin: A Chemometric Approach.

    PubMed

    Locatelli, Monica; Coïsson, Jean Daniel; Travaglia, Fabiano; Bordiga, Matteo; Arlorio, Marco

    2015-08-19

    Hazelnuts belonging to different cultivars or cultivated in different geographic areas can be differentiated by their chemical profile; however, the roasting process may affect the composition of raw hazelnuts, thus compromising the possibility to identify their origin in processed foods. In this work, we characterized raw and roasted hazelnuts (Tonda Gentile Trilobata, TGT, from Italy and from Chile, Tonda di Giffoni from Italy, and Tombul from Turkey), as well as hazelnuts isolated from commercial products, with the aim to discriminate their cultivar and origin. The chemometric evaluation of selected chemical parameters (proximate composition, fatty acids, total polyphenols, antioxidant activity, and protein fingerprint by SDS-PAGE) permitted us to identify hazelnuts belonging to different cultivars and, concerning TGT samples, their different geographic origin. Also commercial samples containing Piedmontese TGT hazelnuts were correctly assigned to TGT cluster. In conclusion, even if the roasting process modifies the composition of roasted hazelnuts, this preliminary model study suggests that the identification of their origin is still possible.

  14. Igneous vs impact processes for the origin of the Mare lavas

    NASA Technical Reports Server (NTRS)

    Gornitz, V.

    1973-01-01

    The respective role of external vs internal processes is considered. The inner Orientale basin was formed by the explosive impact of an asteroidal body. Within minutes after the impact, the concentric fracture system developed as an adjustment to the stresses generated by the shock wave. Examples are presented to illustrate that the upwelling of lava in the center of Mare Orientale and several craters on its ejecta blanket occurred well after the asteroidal collision which generated the bulls-eye structure. Thus, the lavas were not strictly impact melts. However, a close relationship may have existed between the impact and subsequent volcanism.

  15. Sudbury project (University of Muenster-Ontario Geological Survey): Isotope systematics support the impact origin

    NASA Technical Reports Server (NTRS)

    Deutsch, A.; Buhl, D.; Brockmeyer, P.; Lakomy, R.; Flucks, M.

    1992-01-01

    Within the framework of the Sudbury project a considerable number of Sr-Nd isotope analyses were carried out on petrographically well-defined samples of different breccia units. Together with isotope data from the literature these data are reviewed under the aspect of a self-consistent impact model. The crucial point of this model is that the Sudbury Igneous Complex (SIC) is interpreted as a differentiated impact melt sheet without any need for an endogenic 'magmatic' component such as 'impact-triggered' magmatism or 'partial' impact melting of the crust and mixing with a mantle-derived magma.

  16. Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules - An inventory for the origins of life

    NASA Technical Reports Server (NTRS)

    Chyba, Christopher; Sagan, Carl

    1992-01-01

    The contribution of organic-rich comets, carbonaceous asteroids, and interplanetary dust particles and of impact shock-synthesized organics in the atmosphere to the origin of life on earth is studied and quantitatively compared with the principal non-heavy-bombardment sources of prebiotic organics. The results suggest that heavy bombardment before 3.5 Gyr ago either produced or delivered quantities of organics comparable to those produced by other energy sources.

  17. Nd-isotopic evidence for the origin of the Sudbury complex by meteoritic impact

    NASA Technical Reports Server (NTRS)

    Faggart, B. E.; Basu, A. R.; Tatsumoto, M.

    1985-01-01

    A Neodymium isotopic investigation was undertaken in order to determine the possibility that the Sudbury geological structure in Ontario, Canada was formed by meteoritic impact. Conclusive evidence points to the melting of crustal rocks by way of meteoritic impact in the forming of the Sudbury structure.

  18. Deep neck space abscesses of dental origin: the impact of Streptococcus group Milleri.

    PubMed

    Terzic, Andrej; Scolozzi, Paolo

    2014-10-01

    In recent years, there has been rising interest in Streptococcus group Milleri (SM) because high mortality rates have been related to it. In case of deep neck infections (DNI), whatever the origin, mortality rates as high as 26% were reported. But there are no data available for DNI with SM of purely dental origin. The aim of our article was to describe and analyse DNI of purely dental origin involving on one hand SM and on the other hand infections without presence of SM. We compared these two groups and statistically investigated if there were differences in clinical presentation (age, mouth opening, length of hospital stay, laboratory parameters) or clinical behaviour (re-operation, re-hospitalisation, secondary osteomyelitis, stay at intensive care, length of antibiotic treatment, presence of resistances against antibiotics, incapacity to work). For this, we retrospectively searched medical records of our institution for all purulent DNI treated from 2004 till 2012. We found 81 patients meeting all inclusion criteria. Thirty-four patients had involvement of SM, 47 did not. The only statistically significant difference between the SM group and the non-SM group was the length of incapacity to work. All other parameters were non-significant. Furthermore, there were no fatalities. In conclusion, the clinical importance of this article is that patients with deep neck abscesses of purely dental origin involving SM do not need more or different care when compared to all other DNI of dental origin.

  19. Untangling the origin of viruses and their impact on cellular evolution.

    PubMed

    Nasir, Arshan; Sun, Feng-Jie; Kim, Kyung Mo; Caetano-Anollés, Gustavo

    2015-04-01

    The origin and evolution of viruses remain mysterious. Here, we focus on the distribution of viral replicons in host organisms, their morphological features, and the evolution of highly conserved protein and nucleic acid structures. The apparent inability of RNA viral replicons to infect contemporary akaryotic species suggests an early origin of RNA viruses and their subsequent loss in akaryotes. A census of virion morphotypes reveals that advanced forms were unique to viruses infecting a specific supergroup, while simpler forms were observed in viruses infecting organisms in all forms of cellular life. Results hint toward an ancient origin of viruses from an ancestral virus harboring either filamentous or spherical virions. Finally, phylogenetic trees built from protein domain and tRNA structures in thousands of genomes suggest that viruses evolved via reductive evolution from ancient cells. The analysis presents a complete account of the evolutionary history of cells and viruses and identifies viruses as crucial agents influencing cellular evolution. PMID:25758413

  20. Impact origin of the Chesapeake Bay structure and the source of the North American tektites

    USGS Publications Warehouse

    Koeberl, C.; Poag, C.W.; Reimold, W.U.; Brandt, D.

    1996-01-01

    Seismic profiles, drill core samples, and gravity data suggest that a complex impact crater ???35.5 million years old and 90 kilometers in diameter is buried beneath the lower Chesapeake Bay. The breccia that fills the structure contains evidence of shock metamorphism, including impact melt breccias and multiple sets of planar deformation features (shock lamellae) in quartz and feldspar. The age of the crater and the composition of some breccia clasts are consistent with the Chesapeake Bay impact structure being the source of the North American tektites.

  1. Compositional heterogeneity of lunar impact melts: Issues of origin and evolution

    NASA Astrophysics Data System (ADS)

    Dhingra, Deepak; Pieters, Carle

    2012-07-01

    Impact melt formation and emplacement occurs in a dynamically active environment during the excavation and modification stages of the cratering process [1]. They are typically very mobile and as a result occur in a variety of geographical settings including crater floor, walls, rim and beyond. Diverse morphologies of impact melts on the Moon have been well documented [e.g. 2, 3, 4]. Little attention however, has been given to their compositional nature [e.g. 5, 6]. Impact melts occur in diverse geological settings and display wide variability in their volume, liquid to clast ratio and degrees of crystallinity. All these factors affect their physical and chemical attributes. It is therefore necessary to study the compositional nature of impact melts in order to understand their evolution. We have initiated a global remote sensing survey of impact melts on the Moon integrating their compositional character with morphology to understand their evolution. Our initial results suggest compositional heterogeneity in impact melts at various spatial scales [7]. However, it is yet to be understood if the variation is caused by unmelted clast component, the melted target or both. Inefficient mixing of impact melts has been noted at terrestrial impact craters [8] and might be responsible for the heterogeneous composition of impact melts. We are exploring the role of these factors in different environments. In this context, craters with both homogeneous and heterogeneous targets have been selected. Data from Moon Mineralogy Mapper (M3) have been integrated with Kaguya Terrain Camera (TC) and Lunar Reconnaissance Orbiter Narrow Angle Camera (NAC). The integration of these new datasets will enable detailed study of impact melts. Acknowledgment: This research is supported by NLSI grant no. NNA09DB34A References: [1] Grieve R.A.F. et al. (1977) Impact and Expl. Cratering, Eds. D.J. Roddy et al., Pergamon Press, 791-814 [2] Howard and Wilshire (1975) J. Res. U.S. Geol. Surv., 3, 237

  2. Impact of Roasting on Identification of Hazelnut (Corylus avellana L.) Origin: A Chemometric Approach.

    PubMed

    Locatelli, Monica; Coïsson, Jean Daniel; Travaglia, Fabiano; Bordiga, Matteo; Arlorio, Marco

    2015-08-19

    Hazelnuts belonging to different cultivars or cultivated in different geographic areas can be differentiated by their chemical profile; however, the roasting process may affect the composition of raw hazelnuts, thus compromising the possibility to identify their origin in processed foods. In this work, we characterized raw and roasted hazelnuts (Tonda Gentile Trilobata, TGT, from Italy and from Chile, Tonda di Giffoni from Italy, and Tombul from Turkey), as well as hazelnuts isolated from commercial products, with the aim to discriminate their cultivar and origin. The chemometric evaluation of selected chemical parameters (proximate composition, fatty acids, total polyphenols, antioxidant activity, and protein fingerprint by SDS-PAGE) permitted us to identify hazelnuts belonging to different cultivars and, concerning TGT samples, their different geographic origin. Also commercial samples containing Piedmontese TGT hazelnuts were correctly assigned to TGT cluster. In conclusion, even if the roasting process modifies the composition of roasted hazelnuts, this preliminary model study suggests that the identification of their origin is still possible. PMID:26230075

  3. A Splendid Gift from the Earth: The Origins and Impact of the Avermectins (Nobel Lecture).

    PubMed

    Ōmura, Satoshi

    2016-08-22

    Japanese soil was the origin of one of the most important drugs of the world: ivermectin. No other drug has such importance for the health of millions of people, particularly in the poor regions of the world. The discovery of the parent compounds of the avermectines is described first hand by S. Ōmura.

  4. The Impact of Type of Examples on Originality: Explaining Fixation and Stimulation Effects

    ERIC Educational Resources Information Center

    Agogué, Marine; Kazakçi, Akin; Hatchuel, Armand; Le Masson, Pascal; Weil, Benoit; Poirel, Nicolas; Cassotti, Mathieu

    2014-01-01

    There are obstacles to creativity: one of them is called fixation effect, the fact that some knowledge about existing or obvious solutions is spontaneously activated and constrains the generation of new solutions. Converging evidence in cognitive psychology has indicated that the ability to generate original ideas can be limited by recently…

  5. The Impact of Generation and Country of Origin on the Mental Health of Children of Immigrants

    ERIC Educational Resources Information Center

    Montazer, Shirin; Wheaton, Blair

    2011-01-01

    The authors reexamine the study of generational differences in adjustment among the children of immigrants by arguing that the country of origin defines and shapes the adaptation process across generations. Using a sample of children in Toronto, the authors demonstrate that generational differences in the mental health of children occur only in…

  6. Origin of complex impact craters on native oxide coated silicon surfaces

    NASA Astrophysics Data System (ADS)

    Samela, Juha; Nordlund, Kai; Popok, Vladimir N.; Campbell, Eleanor E. B.

    2008-02-01

    Crater structures induced by impact of keV-energy Arn+ cluster ions on silicon surfaces are measured with atomic force microscopy. Complex crater structures consisting of a central hillock and outer rim are observed more often on targets covered with a native silicon oxide layer than on targets without the oxide layer. To explain the formation of these complex crater structures, classical molecular dynamics simulations of Ar cluster impacts on oxide coated silicon surfaces, as well as on bulk amorphous silica, amorphous Si, and crystalline Si substrates, are carried out. The diameter of the simulated hillock structures in the silicon oxide layer is in agreement with the experimental results, but the simulations cannot directly explain the height of hillocks and the outer rim structures when the oxide coated silicon substrate is free of defects. However, in simulations of 5keV /atom Ar12 cluster impacts, transient displacements of the amorphous silicon or silicon oxide substrate surfaces are induced in an approximately 50nm wide area surrounding the impact point. In silicon oxide, the transient displacements induce small topographical changes on the surface in the vicinity of the central hillock. The comparison of cluster stopping mechanisms in the various silicon oxide and silicon structures shows that the largest lateral momentum is induced in the silicon oxide layer during the impact; thus, the transient displacements on the surface are stronger than in the other substrates. This can be a reason for the higher frequency of occurrence of the complex craters on oxide coated silicon.

  7. Order or chaos? Origin and mode of emplacement of breccias in floors of large impact structures

    NASA Astrophysics Data System (ADS)

    Dressler, B. O.; Reimold, W. U.

    2004-09-01

    Breccias in the crater floor of large impact structures are pseudotachylites (sensu largo), authigenic monomict and polymict clastic-matrix breccias, so-called footwall breccias, and impact melt breccias. Pseudotachylite bodies in the center of large impact structures (e.g., Vredefort Dome, South Africa) appear to have a random distribution and orientation, but most dip steeply or vertically. Large bodies of pseudotachylite in the more distal sectors of the >200-km-diameter Sudbury Structure have been interpreted as ring and terrace collapse features. In the Vredefort Dome, networks of randomly distributed pseudotachylite veins accompany large ("mother lode") pseudotachylite dikes. In general, pseudotachylites in the floors of central parts of impact craters may form through explosive transfer of thermal shock energy, in a process that could be termed "flash replacement melting", whereas pseudotachylites at large distances from the centers of large impact structure are believed to have formed through friction leading to partial or complete melting, similar to the formation of tectonic pseudotachylites. In smaller structures (e.g., Ries and Slate Islands), clastic-matrix breccias instead of pseudotachylites occur as the most common breccias in the crater floors. They have a chaotic distribution pattern. Their dips are commonly also steep to vertical. Melt breccia dikes in the target rocks of the crater floor are associated with melt sheets that fill the lower part of the excavation cavity. At Vredefort, erosion has removed the coherent melt sheet, but melt breccia dikes (Vredefort Granophyre) in the crater floor are preserved. They are characterized by a remarkably homogeneous chemical composition and are believed to represent the initial, undifferentiated impact melt. Near the Vredefort collar, the Granophyre forms more or less concentric dikes. In the more central parts of the Dome, their orientation is more random, but, in places, may be controlled by the Archean

  8. Compactional deformation bands in Wingate Sandstone; additional evidence of an impact origin for Upheaval Dome, Utah

    NASA Astrophysics Data System (ADS)

    Okubo, Chris H.; Schultz, Richard A.

    2007-04-01

    Field and microstructural observations from Upheaval Dome, in Canyonlands National Park, Utah, show that inelastic strain of the Wingate Sandstone is localized along compactional deformation bands. These bands are tabular discontinuities (< 0.5 cm thick) that accommodate inelastic shear and compaction of inter-granular volume. Measurements of porosity and grain size from non-deformed samples are used to define a set of capped strength envelopes for the Wingate Sandstone. These strength envelopes reveal that compactional deformation bands require at least ca. 0.7 GPa (and potentially more than 2.3 GPa) of effective mean stress in order to nucleate within this sandstone. We find that the most plausible geologic process capable of generating these required magnitudes of mean stress is a meteoritic impact. Therefore the compactional deformation bands observed within the Wingate Sandstone are additional evidence of an impact event at Upheaval Dome and support a post-Wingate (post-Early Jurassic) age for this impact.

  9. On the origin and composition of Theia: Constraints from new models of the Giant Impact

    NASA Astrophysics Data System (ADS)

    Meier, M. M. M.; Reufer, A.; Wieler, R.

    2014-11-01

    Knowing the isotopic composition of Theia, the proto-planet which collided with the Earth in the Giant Impact that formed the Moon, could provide interesting insights on the state of homogenization of the inner Solar System at the late stages of terrestrial planet formation. We use the known isotopic and modeled chemical compositions of the bulk silicate mantles of Earth and Moon and combine them with different Giant Impact models, to calculate the possible ranges of isotopic composition of Theia in O, Si, Ti, Cr, Zr and W in each model. We compare these ranges to the isotopic composition of carbonaceous chondrites, Mars, and other Solar System materials. In the absence of post-impact isotopic re-equilibration, the recently proposed high angular momentum models of the Giant Impact ("impact-fission", Cúk, M., Stewart, S.T. [2012]. Science 338, 1047; and "merger", Canup, R.M. [2012]. Science 338, 1052) allow - by a narrow margin - for a Theia similar to CI-chondrites, and Mars. The "hit-and-run" model (Reufer, A., Meier, M.M.M., Benz, W., Wieler, R. [2012]. Icarus 221, 296-299) allows for a Theia similar to enstatite-chondrites and other Earth-like materials. If the Earth and Moon inherited their different mantle FeO contents from the bulk mantles of the proto-Earth and Theia, the high angular momentum models cannot explain the observed difference. However, both the hit-and-run as well as the classical or "canonical" Giant Impact model naturally explain this difference as the consequence of a simple mixture of two mantles with different FeO. Therefore, the simplest way to reconcile the isotopic similarity, and FeO dissimilarity, of Earth and Moon is a Theia with an Earth-like isotopic composition and a higher (∼20%) mantle FeO content.

  10. Environmental impacts on soil and groundwater at airports: origin, contaminants of concern and environmental risks.

    PubMed

    Nunes, L M; Zhu, Y-G; Stigter, T Y; Monteiro, J P; Teixeira, M R

    2011-11-01

    Environmental impacts of airports are similar to those of many industries, though their operations expand over a very large area. Most international impact assessment studies and environmental management programmes have been giving less focus on the impacts to soil and groundwater than desirable. This may be the result of the large attention given to air and noise pollution, relegating other environmental descriptors to a second role, even when the first are comparatively less relevant. One reason that contributes to such "biased" evaluation is the lack of systematic information about impacts to soil and groundwater from airport activities, something the present study intends to help correct. Results presented here include the review of over seven hundred documents and online databases, with the objective of obtaining the following information to support environmental studies: (i) which operations are responsible for chemical releases?; (ii) where are these releases located?; (iii) which contaminants of concern are released?; (iv) what are the associated environmental risks? Results showed that the main impacts occur as a result of fuel storage, stormwater runoff and drainage systems, fuel hydrant systems, fuel transport and refuelling, atmospheric deposition, rescue and fire fighting training areas, winter operations, electrical substations, storage of chemical products by airport owners or tenants, and maintenance of green areas. A new method for ranking environmental risks of organic substances, based on chemical properties, is proposed and applied. Results show that the contaminants with the highest risks are the perfluorochemicals, benzene, trichloroethylene and CCl(4). The obtained information provides a basis for establishing the planning and checking phases of environmental management systems, and may also help in the best design of pollution prevention measures in order to avoid or reduce significant environmental impacts from airports.

  11. Glasses of impact origin from Apollo 11, 12, 15, and 16 - Evidence for fractional vaporization and mare/highland mixing

    NASA Technical Reports Server (NTRS)

    Delano, J. W.; Lindsley, D. H.; Rudowski, R.

    1982-01-01

    Electron microprobe analyses have been performed on glasses of impact origin in Apollo 11 breccias (10059, 10060, 10061), Apollo 12 soil (12070), and Apollo 15 breccias (15318, 15425, 15426, 15427). These glasses were produced by shock melting of regolith, rather than of rock. Simple concepts for better understanding and interpreting the chemical data from impact glasses have been developed. These concepts are a significant improvement on earlier strategies, which centered principally on cluster analysis. Using ratios of refractory lithophile elements, the compositional effects of fractional vaporization often associated with impact melting to obtain chemical information about the mare and highland components in the regoliths parental to the glasses have been 'seen through'. This method is also applied to the mare-derived impact glasses from Apollo 16 in order to place constraints on the types of volcanic components occurring in Mare Nectaris. Since impact glasses can be used to derive chemical constraints on the indigenous lithologies comprising multi-component regoliths; the frequent occurrence of these glasses, as well as their low masses, should make them critically important for study when small quantities of grab-samples are returned by future unmanned spacecraft from planets, satellites, and asteroids where regoliths are present.

  12. Numerical simulation of drop impact on a thin film: the origin of the droplets in the splashing regime

    NASA Astrophysics Data System (ADS)

    Xie, Zhihua; Che, Zhizhao; Ismail, Renad; Pain, Chris; Matar, Omar

    2015-11-01

    Drop impact on a liquid layer is a feature of numerous multiphase flow problems, and has been the subject of numerous theoretical, experimental and numerical investigations. In the splashing regime, however, little attention has been focused on the origin of the droplets that are formed during the splashing process. The objective of this study is to investigate this issue numerically in order to improve our understanding of the mechanisms underlying splashing as a function of the relevant system parameters. In contrast to the conventional two-phase flow approach, commonly used to simulate splashing, here, a three-dimensional, three-phase flow model, with adaptive, unstructured meshing, is employed to study the liquid (droplet) - gas (surrounding air) - liquid (thin film) system. In the cases to be presented, both liquid phases have the same fluid property, although, clearly, our method can be used in the more general case of two different liquids. Numerical results of droplet impact on a thin film are analysed to determine whether the origin of the droplets following impact corresponds to the mother drop, or the thin film, or both. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  13. Cleopatra crater on Venus: Venera 15/16 data and impact/volcanic origin controversy

    SciTech Connect

    Basilevsky, A.T. ); Ivanov, B.A. )

    1990-02-01

    Cleopatra structure is a 100-km diameter feature having a morphology similar to that of double-ring basins of the Moon and Mercury and dissimilar to that of volcanic calderas on Mars, Earth, and Venus. The 2.4-km depth of Cleopatra is anomalously large compared to venusian and terrestrial impact craters of equivalent diameters. An impartial summary of the situation is as follows: if Cleopatra is a volcanic caldera, it is a strange caldera, if Cleopatra is an impact crater, it is a strange crater.

  14. Students' Perceptions about Peer Assessment for Writing: Their Origin and Impact on Revision Work

    ERIC Educational Resources Information Center

    Kaufman, Julia H.; Schunn, Christian D.

    2011-01-01

    We investigate students' negative perceptions about an online peer assessment system for undergraduate writing across the disciplines. Specifically, we consider the nature of students' resistance to peer assessment; what factors influence that resistance; and how students' perceptions impact their revision work. We do this work by first examining…

  15. Origin of complex impact craters on native oxide coated silicon surfaces

    SciTech Connect

    Samela, Juha; Nordlund, Kai; Popok, Vladimir N.; Campbell, Eleanor E. B.

    2008-02-15

    Crater structures induced by impact of keV-energy Ar{sub n}{sup +} cluster ions on silicon surfaces are measured with atomic force microscopy. Complex crater structures consisting of a central hillock and outer rim are observed more often on targets covered with a native silicon oxide layer than on targets without the oxide layer. To explain the formation of these complex crater structures, classical molecular dynamics simulations of Ar cluster impacts on oxide coated silicon surfaces, as well as on bulk amorphous silica, amorphous Si, and crystalline Si substrates, are carried out. The diameter of the simulated hillock structures in the silicon oxide layer is in agreement with the experimental results, but the simulations cannot directly explain the height of hillocks and the outer rim structures when the oxide coated silicon substrate is free of defects. However, in simulations of 5 keV/atom Ar{sub 12} cluster impacts, transient displacements of the amorphous silicon or silicon oxide substrate surfaces are induced in an approximately 50 nm wide area surrounding the impact point. In silicon oxide, the transient displacements induce small topographical changes on the surface in the vicinity of the central hillock. The comparison of cluster stopping mechanisms in the various silicon oxide and silicon structures shows that the largest lateral momentum is induced in the silicon oxide layer during the impact; thus, the transient displacements on the surface are stronger than in the other substrates. This can be a reason for the higher frequency of occurrence of the complex craters on oxide coated silicon.

  16. Impact origin of the Avak structure, Arctic Alaska, and genesis of the Barrow gas fields

    SciTech Connect

    Kirschner, C.E. ); Grantz, A.; Mullen, M.W. )

    1992-05-01

    Geophysical and subsurface geologic data suggest that the Avak structure, which underlies the Arctic Coastal Plain 12 km southeast of Barrow, Alaska, is a hypervelocity meteorite or comet impact structure. The structure is a roughly circular area of uplifted, chaotically deformed Upper Triassic to Lower Cretaceous sedimentary rocks 8 km in diameter that is bounded by a ring of anastomosing, inwardly dipping, listric normal faults 12 km in diameter. A zone of gently outward-dipping sedimentary country rocks forms a discontinuous ring of rim anticlines within the peripheral ring of normal faults. Beyond these anticlines, the sedimentary rocks are almost flat-lying. Data concerning the age of the Avak structure are not definitive. If submarine landslide deposits in the upper part of the Aptian and Albian Torok Formation, in the subsurface 200 km to the east, were triggered by the Avak event, then the Avak meteorite struck a submerged marine shelf about 100 [plus minus] 5 Ma. However, the impact features found at Avak characterize the distal zones of meteorite impact structures. Fused rocks, plastic deformation, and shock-metamorphic minerals found in more proximal zones of impact structures are apparently missing. These observations, and the lack of Avak ejecta in cuttings and cores from the Torok Formation and Nanushuk Group in surrounding test wells, indicate that the impact event postdated these beds. In this case, the Avak meteorite struck a Late Cretaceous or Tertiary marine shelf or coastal plain between the Cenomanian (ca. 95 Ma), and deposition of the basal beds of the overlying late Pliocene and Quaternary Gubik Formation (ca. 3 Ma).

  17. A Large Impact Origin for Sputnik Planum and Surrounding Terrains, Pluto?

    NASA Astrophysics Data System (ADS)

    Schenk, Paul M.; McKinnon, William; Moore, Jeffrey; Nimmo, Francis; Stern, S. Alan; Weaver, Hal; Ennico, Kimberly; Olkin, Cathy; Young, Leslie

    2015-11-01

    One of the most prominent features on Pluto discovered by New Horizons is the oval-shaped bright deposit within western Tombaugh Regio (all names used herein are informal). This smooth bright deposit, provisionally identified with frozen nitrogen and methane and informally referred to as Sputnik Planum, is bounded on the northeast by an arcuate scarp (Cousteau Rupes). The smooth bright material there embays what appears to be an eroded plateau 1-2 km high. The arcuate scarp leads to speculation that the deposits formed in an ancient impact basin, but detailed mapping at 2 km pixel scales suggests that this large structure is more complex than any simple impact basin. To the southwest are a series of high peaks and massifs (also embayed by bright material) but these broken massifs have a different morphology from Cousteau Rupes, being both higher and more disrupted. The southern section of this putative 800-km-wide circular structure is completely missing as smooth material extends well to the south of the nominal rim location. A possible analog occurs at the “other End of the Solar System” on Mercury, in Caloris Basin. This 1400-km-wide impact basin is also irregular in shape, with large deviations form circularity, and occasional large massifs along some rim segments. Post-impact smooth plains embay the rim scarp in some areas, though these are likely to be volcanic plains on Mercury. The relief of the rim scarps to the NE and SW and putative evidence for convection within Sputnik Planum suggests that the floor of the deposits lies 1-3 km below the mean surface (pending stereo mapping). This depth is consistent with the filling of an ancient impact basin with ices, deposited either volcanically or atmospherically, although other explanations are also possible. This work was supported by NASA's New Horizons project.

  18. Origin and emplacement of impactites in the Chesapeake Bay impact structure, Virginia, USA

    USGS Publications Warehouse

    Horton, J.W.; Gohn, G.S.; Powars, D.S.; Edwards, L.E.

    2007-01-01

    The late Eocene Chesapeake Bay impact structure, located on the Atlantic margin of Virginia, may be Earth's best-preserved large impact structure formed in a shallow marine, siliciclastic, continental-shelf environment. It has the form of an inverted sombrero in which a central crater ???40 km in diameter is surrounded by a shallower brim, the annular trough, that extends the diameter to ???85 km. The annular trough is interpreted to have formed largely by the collapse and mobilization of weak sediments. Crystalline-clast suevite, found only in the central crater, contains clasts and blocks of shocked gneiss that likely were derived from the fragmentation of the central-uplift basement. The suevite and entrained megablocks are interpreted to have formed from impact-melt particles and crystalline-rock debris that never left the central crater, rather than as a fallback deposit. Impact-modified sediments in the annular trough include megablocks of Cretaceous nonmarine sediment disrupted by faults, fluidized sands, fractured clays, and mixed-sediment intercalations. These impact-modified sediments could have formed by a combination of processes, including ejection into and mixing of sediments in the water column, rarefaction-induced fragmentation and clastic injection, liquefaction and fluidization of sand in response to acoustic-wave vibrations, gravitational collapse, and inward lateral spreading. The Exmore beds, which blanket the entire crater and nearby areas, consist of a lower diamicton member overlain by an upper stratified member. They are interpreted as unstratified ocean-resurge deposits, having depositional cycles that may represent stages of inward resurge or outward anti-resurge flow, overlain by stratified fallout of suspended sediment from the water column. ?? 2008 The Geological Society of America. All rights reserved.

  19. The Apollo 15 yellow impact glasses - Chemistry, petrology, and exotic origin

    NASA Technical Reports Server (NTRS)

    Delano, J. W.; Lindsley, D. H.; Ma, M.-S.; Schmitt, R. A.

    1982-01-01

    The Apollo 15 yellow impact glasses are characterized by moderate TiO2 (about 4.8%) and high abundances of the large ion lithophile elements (e.g., K, P, Hf, Th, REE). Since the chemistry of these glasses cannot be duplicated by any combination of local components presently known to occur at the Apollo 15 landing site, these yellow glasses seem to be exotic to that area. Chemical and petrologic constraints suggest that these samples were produced by impact melting of an immature mare regolith developed upon an unusual variety of mare basalt. It is speculated that the target basalts were the youngest lava flows known to exist on the moon (i.e., Eratosthenian-age lavas in Oceanus Procellarum and Mare Imbrium). Specific tests are proposed for evaluating this provocative hypothesis.

  20. Impact melting of frozen oceans on the early Earth: implications for the origin of life

    NASA Technical Reports Server (NTRS)

    Bada, J. L.; Bigham, C.; Miller, S. L.

    1994-01-01

    Without sufficient greenhouse gases in the atmosphere, the early Earth would have become a permanently frozen planet because the young Sun was less luminous than it is today. Several resolutions to this faint young Sun-frozen Earth paradox have been proposed, with an atmosphere rich in CO2 being the one generally favored. However, these models assume that there were no mechanisms for melting a once frozen ocean. Here we show that bolide impacts between about 3.6 and 4.0 billion years ago could have episodically melted an ice-covered early ocean. Thaw-freeze cycles associated with bolide impacts could have been important for the initiation of abiotic reactions that gave rise to the first living organisms.

  1. Impact melting of frozen oceans on the early Earth: implications for the origin of life.

    PubMed

    Bada, J L; Bigham, C; Miller, S L

    1994-02-01

    Without sufficient greenhouse gases in the atmosphere, the early Earth would have become a permanently frozen planet because the young Sun was less luminous than it is today. Several resolutions to this faint young Sun-frozen Earth paradox have been proposed, with an atmosphere rich in CO2 being the one generally favored. However, these models assume that there were no mechanisms for melting a once frozen ocean. Here we show that bolide impacts between about 3.6 and 4.0 billion years ago could have episodically melted an ice-covered early ocean. Thaw-freeze cycles associated with bolide impacts could have been important for the initiation of abiotic reactions that gave rise to the first living organisms.

  2. [Assessment of the impact of GMO of plant origin on rat progeny development in 3 generations].

    PubMed

    Tyshko, N V; Zhminchenko, V M; Pashorina, V A; Seliaskin, K E; Saprykin, V P; Utembaeva, N T; Tutel'ian, V A

    2011-01-01

    The publication presents the results of assessment of impact of genetically modified (GM) maize Liberty Link on prenatal and postnatal development of progeny of 3 generations of Wistar rats. A total of 630 adult animals and 2837 pups were used in the experiment. The animals were divided into 5 groups which got the diets with inclusion of maize: the animals of the experimental group got the diet with the GM-maize, animals of the control group - with near isogenic conventional analogue of the GM-maize, animals of the 1st, 2nd and 3rd reference groups - conventional varieties of maize ROSS 144 MV, ROSS 197 MVW, Dokuchayevskaya 250 MV respectively. The maize was included in the diet at maximum possible level not violating the balance of basic nutrients. Analysis of the data obtained during the study did not reveal any impact of GM-maize on rat progeny development. PMID:21574464

  3. [Assessment of the impact of GMO of plant origin on rat progeny development in 3 generations].

    PubMed

    Tyshko, N V; Zhminchenko, V M; Pashorina, V A; Seliaskin, K E; Saprykin, V P; Utembaeva, N T; Tutel'ian, V A

    2011-01-01

    The publication presents the results of assessment of impact of genetically modified (GM) maize Liberty Link on prenatal and postnatal development of progeny of 3 generations of Wistar rats. A total of 630 adult animals and 2837 pups were used in the experiment. The animals were divided into 5 groups which got the diets with inclusion of maize: the animals of the experimental group got the diet with the GM-maize, animals of the control group - with near isogenic conventional analogue of the GM-maize, animals of the 1st, 2nd and 3rd reference groups - conventional varieties of maize ROSS 144 MV, ROSS 197 MVW, Dokuchayevskaya 250 MV respectively. The maize was included in the diet at maximum possible level not violating the balance of basic nutrients. Analysis of the data obtained during the study did not reveal any impact of GM-maize on rat progeny development.

  4. Socrates' questions: a focus for nursing.

    PubMed

    Bunkers, Sandra S

    2004-07-01

    This column focuses on the philosophical dialogue originated by Socrates. Six questions that Socrates would ask the ancient Greeks are explored in discussing a book written by Phillips entitled Six Questions of Socrates. These questions were: What is virtue? What is moderation? What is justice? What is good? What is courage? What is piety? A human becoming perspective is used as a lens to view the discussion on these questions and the question is posed, "What would it be like to frame discussions on health and quality of life around Socrates' questions?" Parse's teaching-learning processes are presented as a means of creating an environment where dialogue on these questions can occur.

  5. Cleopatra crater on Venus - Venera 15/16 data and impact/volcanic origin controversy

    NASA Astrophysics Data System (ADS)

    Basilevsky, A. T.; Ivanov, B. A.

    1990-02-01

    The morphology and morphometry of the 100-km diameter, 2.4-km deep Cleopatra crater on Venus are examined using Venera 15/16 images. The Cleopatra crater is compared to circular structures on Venus, Mercury, Mars, the earth and the moon. Consideration is given to the possible causes for the genesis of the Cleopatra crater. It is concluded that Cleopatra has a clear impact basin morphology with an anomalous crater depth.

  6. Petrographic and geochemical evidence for an allochthonous, possibly impact melt, origin of pseudotachylite from the Vredefort Dome, South Africa

    NASA Astrophysics Data System (ADS)

    Lieger, Daniel; Riller, Ulrich; Gibson, Roger L.

    2011-08-01

    Hypotheses proposed to explain the origin of pseudotachylite bodies formed during impact cratering include: (1) frictional heating, (2) shock loading, (3) decompression or (4) drainage of impact melt into target rocks. In order to differentiate among these processes, we conducted detailed geochemical and petrographic analysis of the matrices in pseudotachylitic veins and dikes and of their respective wall rocks. Our analyses indicate that the chemical compositions of matrices locally deviate significantly from their immediate wall rocks and that assimilation of wall rock has substantially modified the pseudotachylite matrix compositions in places. Variable magnitudes of assimilation can be explained by the surface area of wall rock or its fragments in contact with melt, as well as the initial temperature and cooling rate of the pseudotachylitic melt. Chemical trends observed can be explained either by admixture of an exotic melt component with immediate wall rock or by mixing of melts derived from local lithologies. Trends in the compositional deviation of centimetre to metre-wide pseudotachylite dikes from their immediate wall rocks are consistent with the presence of a primary melt component having granitoid composition akin to the average composition of Vredefort Granophyre dikes. Within veins, melt transport can be geochemically and petrographically traced for distances of centimetres to metres, with the direction of melt transport from larger pseudotachylite veins toward smaller ones and into apophyses. Sulphide and silicate mineralogy indicates that the initial temperature of pseudotachylitic melt must have been at least 1200-1700 °C. Collectively, these characteristics point to an allochthonous origin of pseudotachylitic melt . We advocate the possibility that impact melt from the initially superheated impact melt sheet contributed to the formation of pseudotachylite bodies at Vredefort.

  7. Impact glasses from Zhamanshin crater (U.S.S.R.) - Chemical composition and discussion of origin

    NASA Astrophysics Data System (ADS)

    Koeberl, C.; Fredriksson, K.

    1986-05-01

    Three silica-rich zhamanshinites and one irghizite from the Zhamanshin impact crater (northern Aral area, U.S.S.R.) have been analyzed for up to 40 major, minor, and trace elements. All data point to a clear distinction between these impact glasses and other tektites or impact glasses, e.g. from the Australasian strewn field. Halogens are generally enriched in the irghizites and zhamanshinites when compared to normal splash for tektites, with zhamanshinites enriched more than irghizites. The same holds also for the alkali metals and a number of other volatile elements like Sb and As. Nickel and cobalt are enriched in the irghizite sample to a considerable degree, suggesting meteoritic contamination. This view is also supported by gold and selenium data, but for quantifications other siderophile elements need to be considered. Chromium is not a valid indicator of meteoritic contamination, because small amounts of ultra-basic igneous material may completely alter the picture. The rare earth elements do show a sedimentary pattern, consistent with two or three different source materials and a variation which is probably mostly due to dilution with silica-rich materials. The peak pressure and temperature experienced by the irghizites was lower than for australites or other splash-form tektites, and even lower for zhamanshinites, which is revealed by the content of volatile elements and lesser homogeneity.

  8. Comparative ionospheric impacts and solar origins of nine strong geomagnetic storms in 2010-2015

    NASA Astrophysics Data System (ADS)

    Wood, Brian E.; Lean, Judith L.; McDonald, Sarah E.; Wang, Yi-Ming

    2016-06-01

    For nine of the strongest geomagnetic storms in solar cycle 24 we characterize, quantify, and compare the impacts on ionospheric total electron content (TEC) and the U.S. Wide Area Augmentation System (WAAS) with the heliospheric morphology and kinematics of the responsible coronal mass ejections (CMEs) and their solar source regions. Regional TEC responses to the events are similar in many respects, especially in the initial positive phase. For the subsequent negative phase, Dst is a better indicator than ap of the magnitude of the TEC decrease. The five events that arrive between 13:00 UT and 21:00 UT (local daytime in the U.S.) produce large WAAS degradations, and the four events that arrive outside this time of day produce lesser or no WAAS degradation. Our sample of geoeffective events includes CMEs with only modestly fast speeds, ones that only provided glancing impacts on Earth by their shock sheaths and ones not associated with any significant flare. While all of the CMEs traveled faster than the solar wind, they nevertheless have a wide range of velocities and produced a range of Bz values; neither speed nor Bz correlates significantly with ionospheric impact. Comparison with the locations of surface activity leads to estimates of deflection for the CMEs, with the average deflection being 19°. At least a few events may have missed Earth entirely in the absence of coronal deflection.

  9. Impact-driven planetary desiccation: The origin of the dry Venus

    NASA Astrophysics Data System (ADS)

    Kurosawa, Kosuke

    2015-11-01

    The fate of surface water on Venus is one of the most important outstanding problems in comparative planetology. Although Venus should have had a large amount of surface water (like the Earth) during its formation, the current water content on the Venusian surface is only 1 part in 100 000 of that of the mass of Earth's oceans. Here a new concept is proposed to explain water removal on a steam-covered proto Venus, referred to as "impact-driven planetary desiccation". Since a steam atmosphere is photochemically unstable, water vapor dissociates into hydrogen and oxygen. Then, hydrogen escapes easily into space through hydrodynamic escape driven by strong extreme ultraviolet radiation from the young Sun. The focus is on the intense impact bombardment during the terminal stage of planetary accretion as generators of a significant amount of reducing agent. The fine-grained ejecta remove the residual oxygen, the counter part of escaped hydrogen, via the oxidation of iron-bearing rocks in a hot atmosphere. Thus, hypervelocity impacts cause net desiccation of the planetary surface. I constructed a stochastic cratering model using a Monte Carlo approach to investigate the cumulative mass of nonoxidized, ejected rocks due to the intense impact bombardment. The ejecta mass after each impact was calculated using the π-group scaling laws and a modified Maxwell's Z model. The effect of projectile penetration into the ground on the ejecta mass was also included. Next, an upper limit on the total amount of removed water was calculated using the stoichiometric limit of the oxidation of basaltic rocks, taking into account the effect of fast H2 escape. It is shown that a thick steam atmosphere with a mass equivalent to that of the terrestrial oceans would be removed. The cumulative mass of rocky ejecta released into the atmosphere reaches 1 wt% of the host planet, which is 10 000 times of the current mass of the Earth's atmosphere. These results strongly suggest that chemical

  10. BICEP2, Planck, spinorial space-time, pre-Big Bang.. On the possible origin of primordial CMB B-modes and gravitational waves. Potentialities of alternative cosmologies and open questions

    NASA Astrophysics Data System (ADS)

    Gonzalez-Mestres, Luis

    2015-05-01

    The field of Cosmology is currently undergoing a positive and constructive crisis. Controversies concerning inflation are not really new. But after the 2013-2014 Planck and BICEP2 announcements, and the more recent joint analysis by Planck, BICEP2 and the Keck Array (PBKA), the basic issues can involve more direct links between the Mathematical Physics aspects of cosmological patterns and the interpretation of experimental results. Open questions and new ideas on the foundations of Cosmology can emerge, while future experimental and observational programs look very promising. The BICEP2 result reporting an excess of B-mode polarization signal of the cosmic microwave background (CMB) radiation was initially presented as a signature of primordial gravitational waves from cosmic inflation. But polarized dust emission can be at the origin of such a signal, and the evidence claimed by BICEP2 is no longer secure after the PBKA analysis. Furthermore, even assuming that significant CMB B-mode polarization has indeed been generated by the early Universe, its theoretical and cosmological interpretation would be far from obvious. Inflationary gravitational waves are not the only possible source of primordial CMB B-modes. Alternative cosmologies such as pre-Big Bang patterns and the spinorial space-time (SST) we introduced in 1996-97 can naturally produce this polarization. Furthermore, the SST automatically generates for each comoving observer a local privileged space direction (PSD) whose existence may have been confirmed by Planck data. If such a PSD exists, vector perturbations have most likely been strong in the early Universe and may have produced CMB B-modes. Pre-Big Bang cosmologies can also generate gravitational waves in the early Universe without inflation. After briefly describing detectors devoted to the study of the CMB polarization, we discuss the situation emerging from BICEP2 results, Planck results and the PBKA analysis. In particular, we further analyze

  11. Evidence for an 800 km Diameter Impact Structure in Meridiani Planum and Associated Channels and Basins: A Connection with the Origin of the Hematite Deposits?

    NASA Technical Reports Server (NTRS)

    Newsom, H. E.; Barber, C. A.; Schelble, R. T.; Hare, T. M.; Feldman, W. C.; Sutherland, V.; Gordon, H.; Thorsos, I. E.; Livingston, A.; Lewis, K.

    2003-01-01

    Topographic evidence for the existence of an early 800 km diameter multi-ringed impact structure, and evidence for fluvial and lacustrine environments in Meridiani Planum suggests a connection with the origin of the hematite deposits present in the region.

  12. Impact of fermentation on nitrogenous compounds of cocoa beans (Theobroma cacao L.) from various origins.

    PubMed

    Hue, C; Gunata, Z; Breysse, A; Davrieux, F; Boulanger, R; Sauvage, F X

    2016-02-01

    Tangential filtration technique was used to separate and quantify three different fractions of nitrogenous compounds depending on their molecular size, during cocoa fermentation. On every phenotype and origin analyzed, protein profile of non-fermented samples was similar. During fermentation course, proteins get degraded with a concomitant increase in amino acids content. Peptides between 3 and 10 kDa were observed at low levels. A strong correlation between amino acids and ammonia nitrogen, a fermentation marker was found. Attention was drawn on each fraction, and enabled to point out other phenomenon occurring during fermentation. The migration of some nitrogenous compounds towards the bean shell during fermentation was demonstrated. Acetone treatment of cocoa powder prior to SDS-PAGE led to losses of nitrogenous compounds. This result gives clues on the tanning phenomenon carried out by polyphenols on nitrogenous compounds, phenomenon which increases during fermentation.

  13. Metabolites of Microbial Origin with an Impact on Health: Ochratoxin A and Biogenic Amines.

    PubMed

    Russo, Pasquale; Capozzi, Vittorio; Spano, Giuseppe; Corbo, Maria R; Sinigaglia, Milena; Bevilacqua, Antonio

    2016-01-01

    Safety and quality are significant challenges for food; namely, safety represents a big threat all over the world and is one of the most important goal to be achieved in both Western Society and Developing Countries. Wine safety mainly relies upon some metabolites and many of them are of microbial origin. The main goal of this review is a focus on two kinds of compounds (biogenic amines and mycotoxins, mainly Ochratoxin A) for their deleterious effects on health. For each class of compounds, we will focus on two different traits: (a) synthesis of the compounds in wine, with a brief description of the most important microorganisms and factors leading this phenomenon; (b) prevention and/or correction strategies and new trends. In addition, there is a focus on a recent predictive tool able to predict toxin contamination of grape, in order to perform some prevention approaches and achieve safe wine. PMID:27092133

  14. Family support and family-centered care in the neonatal intensive care unit: origins, advances, impact.

    PubMed

    Gooding, Judith S; Cooper, Liza G; Blaine, Arianna I; Franck, Linda S; Howse, Jennifer L; Berns, Scott D

    2011-02-01

    Family-centered care (FCC) has been increasingly emphasized as an important and necessary element of neonatal intensive care. FCC is conceptualized as a philosophy with a set of guiding principles, as well as a cohort of programs, services, and practices that many hospitals have embraced. Several factors drive the pressing need for family-centered care and support of families of infants in NICUs, including the increase in the number of infants in NICUs; growth in diversity of the population and their concurrent needs; identification of parental and familial stress and lack of parenting confidence; and gaps in support for families, as identified by parents and NICU staff. We explore the origins of and advances in FCC in the NICU and identify various delivery methods and aspects of FCC and family support in the NICU. We examine the research and available evidence supporting FCC in the NICU and offer recommendations for increased dissemination and for future study.

  15. The origin of Pasteurella multocida impacts pathology and inflammation when assessed in a mouse model.

    PubMed

    Pors, Susanne E; Chadfield, Mark S; Sørensen, Dorte B; Offenberg, Hanne; Bisgaard, Magne; Jensen, Henrik E

    2016-04-01

    Host-pathogen interactions of Pasteurella multocida isolates of different origin were studied in a mouse model, focusing on pathology, bacterial load and expression of the metalloproteinase MMP9 and its inhibitor TIMP1. Intranasal inoculation with one of three doses (10(6), 10(4), 10(2)CFU) of an isolate from porcine pneumonia or fowl cholera showed marked differences between the two isolates. The avian isolate was highly pathogenic with severe signs of necrotizing pneumonia, liver necrosis and high bacterial load in lung and liver. Clinical signs and pathology related to the porcine isolate were dose dependent and consisted of exudative bronchopneumonia, abscess formation in liver and a lower bacterial load in lung and liver. Both isolates caused increased expression of MMP9 and TIMP1. In conclusion, evaluation and comparison of pathogenicity and host-pathogen interaction of P. multocida isolates from different hosts is possible in the intranasal murine model. PMID:27033923

  16. Metabolites of Microbial Origin with an Impact on Health: Ochratoxin A and Biogenic Amines

    PubMed Central

    Russo, Pasquale; Capozzi, Vittorio; Spano, Giuseppe; Corbo, Maria R.; Sinigaglia, Milena; Bevilacqua, Antonio

    2016-01-01

    Safety and quality are significant challenges for food; namely, safety represents a big threat all over the world and is one of the most important goal to be achieved in both Western Society and Developing Countries. Wine safety mainly relies upon some metabolites and many of them are of microbial origin. The main goal of this review is a focus on two kinds of compounds (biogenic amines and mycotoxins, mainly Ochratoxin A) for their deleterious effects on health. For each class of compounds, we will focus on two different traits: (a) synthesis of the compounds in wine, with a brief description of the most important microorganisms and factors leading this phenomenon; (b) prevention and/or correction strategies and new trends. In addition, there is a focus on a recent predictive tool able to predict toxin contamination of grape, in order to perform some prevention approaches and achieve safe wine. PMID:27092133

  17. Impact of fermentation on nitrogenous compounds of cocoa beans (Theobroma cacao L.) from various origins.

    PubMed

    Hue, C; Gunata, Z; Breysse, A; Davrieux, F; Boulanger, R; Sauvage, F X

    2016-02-01

    Tangential filtration technique was used to separate and quantify three different fractions of nitrogenous compounds depending on their molecular size, during cocoa fermentation. On every phenotype and origin analyzed, protein profile of non-fermented samples was similar. During fermentation course, proteins get degraded with a concomitant increase in amino acids content. Peptides between 3 and 10 kDa were observed at low levels. A strong correlation between amino acids and ammonia nitrogen, a fermentation marker was found. Attention was drawn on each fraction, and enabled to point out other phenomenon occurring during fermentation. The migration of some nitrogenous compounds towards the bean shell during fermentation was demonstrated. Acetone treatment of cocoa powder prior to SDS-PAGE led to losses of nitrogenous compounds. This result gives clues on the tanning phenomenon carried out by polyphenols on nitrogenous compounds, phenomenon which increases during fermentation. PMID:26304435

  18. Origin of the sudbury complex by meteoritic impact: neodymium isotopic evidence.

    PubMed

    Faggart, B E; Basu, A R; Tatsumoto, M

    1985-10-25

    Samarium-neodymium isotopic data on whole rocks and minerals of the Sudbury Complex in Canada gave an igneous crystallization age of 1840 +/- 21 x 10(6) years. The initial epsilon neodymium values for 15 whole rocks are similar to those for average upper continental crust, falling on the crustal trend of neodymium isotopic evolution as defined by shales. The rare earth element concentration patterns of Sudbury rocks are also similar to upper crustal averages. These data suggest that the Sudbury Complex formed from melts generated in the upper crust and are consistent with a meteoritic impact.

  19. Origin of the Sudbury Complex by meteoritic impact: Neodymium isotopic evidence

    USGS Publications Warehouse

    Faggart, B.E.; Basu, A.R.; Tatsumoto, M.

    1985-01-01

    Samarium-neodymium isotopic data on whole rocks and minerals of the Sudbury Complex in Canada gave an igneous crystallization age of 1840 ?? 21 ?? 106 years. The initial epsilon neodymium values for 15 whole rocks are similar to those for average upper continental crust, falling on the crustal trend of neodymium isotopic evolution as defined by shales. The rare earth element concentration patterns of Sudbury rocks are also similar to upper crustal averages. These data suggest that the Sudbury Complex formed from melts generated in the upper crust and are consistent with a meteoritic impact.

  20. Crystal-bearing lunar spherules: Impact-melting of the Moon's crust and implications for the origin of meteoritic chondrules

    NASA Astrophysics Data System (ADS)

    Ruzicka, Alex; Snyder, Gregory A.; Taylor, Lawrence A.

    2000-01-01

    establishing the compositions of CLSs than of chondrules. However, the many detailed similarities between CLSs and chondrules indicate that it is more difficult to rule out an origin for some chondrules by impact-melting than some have previously argued. Differences between CLSs, chondrules, and their host rocks possibly can be reconciled with an impact-melt origin for some chondrules when different precursors, the higher gravity of the Moon compared to chondrite parent bodies, and the likely presence of nebular gas during chondrule formation are taken into account.

  1. Evaluation d'impact sur la santé et évaluation d'impact sur l'équité en santé : éventail de pratiques et questions de recherche.

    PubMed

    Villeval, Mélanie; Bidault, Elsa; Lang, Thierry

    2016-09-01

    L'Evaluation d'Impact sur la Santé (EIS) se développe au niveau international et est encore au stade émergent en France. Elle vise à évaluer les effets positifs et négatifs potentiels d'un projet, d'un programme ou d'une politique sur la santé. L'objectif est de produire des recommandations en direction des décideurs, afin d'en maximiser les effets positifs et d'en diminuer les effets négatifs. L'EIS est un moyen particulièrement intéressant d'action sur les déterminants de la santé au-delà des comportements individuels et du système de santé. Les politiques de logement, de transport, de solidarité, économiques, etc. ont, en effet, des impacts souvent non prévus sur la santé. Au-delà des effets sur la santé, l'EIS doit aussi permettre d'apprécier la distribution de ces effets dans la population.Si la préoccupation pour l'équité en santé est centrale dans l'EIS, elle reste cependant difficilement traduite en pratique. Face à cette difficulté, des démarches d'évaluation d'impact ont été développées pour renforcer la prise en compte de l'équité à chaque étape de l'EIS ou « Equity Focused Health Impact Assessment », ou prendre en compte les impacts sur les inégalités de santé de façon spécifique. Ainsi, l'Evaluation de l'Impact sur l'Equité en Santé (EIES) semble, par exemple, particulièrement intéressante pour évaluer l'impact sur les inégalités de projets dans le champ sanitaire.L'EIS et l'EIES posent de nombreuses questions de recherche, notamment autour de la réunion, dans une même démarche, du politique, du citoyen et de l'expert. La participation des populations vulnérables potentiellement affectées par la politique évaluée est une valeur centrale de l'EIS, mais pose des questions d'acceptabilité sociale. La collaboration avec les décideurs politiques est également un enjeu majeur. Les difficultés méthodologiques, notamment de quantification des impacts, peuvent constituer des freins à la promotion

  2. Evaluation d'impact sur la santé et évaluation d'impact sur l'équité en santé : éventail de pratiques et questions de recherche.

    PubMed

    Villeval, Mélanie; Bidault, Elsa; Lang, Thierry

    2016-09-01

    L'Evaluation d'Impact sur la Santé (EIS) se développe au niveau international et est encore au stade émergent en France. Elle vise à évaluer les effets positifs et négatifs potentiels d'un projet, d'un programme ou d'une politique sur la santé. L'objectif est de produire des recommandations en direction des décideurs, afin d'en maximiser les effets positifs et d'en diminuer les effets négatifs. L'EIS est un moyen particulièrement intéressant d'action sur les déterminants de la santé au-delà des comportements individuels et du système de santé. Les politiques de logement, de transport, de solidarité, économiques, etc. ont, en effet, des impacts souvent non prévus sur la santé. Au-delà des effets sur la santé, l'EIS doit aussi permettre d'apprécier la distribution de ces effets dans la population.Si la préoccupation pour l'équité en santé est centrale dans l'EIS, elle reste cependant difficilement traduite en pratique. Face à cette difficulté, des démarches d'évaluation d'impact ont été développées pour renforcer la prise en compte de l'équité à chaque étape de l'EIS ou « Equity Focused Health Impact Assessment », ou prendre en compte les impacts sur les inégalités de santé de façon spécifique. Ainsi, l'Evaluation de l'Impact sur l'Equité en Santé (EIES) semble, par exemple, particulièrement intéressante pour évaluer l'impact sur les inégalités de projets dans le champ sanitaire.L'EIS et l'EIES posent de nombreuses questions de recherche, notamment autour de la réunion, dans une même démarche, du politique, du citoyen et de l'expert. La participation des populations vulnérables potentiellement affectées par la politique évaluée est une valeur centrale de l'EIS, mais pose des questions d'acceptabilité sociale. La collaboration avec les décideurs politiques est également un enjeu majeur. Les difficultés méthodologiques, notamment de quantification des impacts, peuvent constituer des freins à la promotion

  3. Impact of Parental Bos taurus and Bos indicus Origins on Copy Number Variation in Traditional Chinese Cattle Breeds

    PubMed Central

    Zhang, Liangzhi; Jia, Shangang; Plath, Martin; Huang, Yongzhen; Li, Congjun; Lei, Chuzhao; Zhao, Xin; Chen, Hong

    2015-01-01

    Copy number variation (CNV) is an important component of genomic structural variation and plays a role not only in evolutionary diversification but also in domestication. Chinese cattle were derived from Bos taurus and Bos indicus, and several breeds presumably are of hybrid origin, but the evolution of CNV regions (CNVRs) has not yet been examined in this context. Here, we of CNVRs, mtDNA D-loop sequence variation, and Y-chromosomal single nucleotide polymorphisms to assess the impact of maternal and paternal B. taurus and B. indicus origins on the distribution of CNVRs in 24 Chinese domesticated bulls. We discovered 470 genome-wide CNVRs, only 72 of which were shared by all three Y-lineages (B. taurus: Y1, Y2; B. indicus: Y3), whereas 265 were shared by inferred taurine or indicine paternal lineages, and 228 when considering their maternal taurine or indicine origins. Phylogenetic analysis uncovered eight taurine/indicine hybrids, and principal component analysis on CNVs corroborated genomic exchange during hybridization. The distribution patterns of CNVRs tended to be lineage-specific, and correlation analysis revealed significant positive or negative co-occurrences of CNVRs across lineages. Our study suggests that CNVs in Chinese cattle partly result from selective breeding during domestication, but also from hybridization and introgression. PMID:26260653

  4. The origin of the moon and the single-impact hypothesis III.

    PubMed

    Benz, W; Cameron, A G; Melosh, H J

    1989-01-01

    In previous papers in this series the smoothed particle hydrodynamics method (SPH) has been used to explore the conditions in which a major planetary collision may have been responsible for the formation of the Moon. In Paper II (W. Benz, W.L. Slattery, and A.G.W. Cameron 1987, Icarus 71, 30-45) it was found that the optimum conditions were obtained when the mass ratio of the impactor to the protoearth was 0.136. In the present paper we investigate the importance of the equation of state by running this optimum case several times and varying the equation of state and other related parameters. The two equations of state compared are the Tillotson (used in the previous papers) and the CHART D/CSQ ANEOS. Because of differences in these equations of state, including the fact that different types of rocks were used in association with each, it was not possible to prepare initial planetary models that were comparable in every respect, so several different simulations were necessary in which different planetary parameters were matched between the equations of state. We also used a new version of the SPH code. The results reaffirmed the previous principal conclusions: the collisions produced a disk of rocky material in orbit, with most of the material derived from the impacting object. These results indicate that the equation of state is not a critical factor in determining the amount of material thrown into orbit. This confirms the conclusions of Paper II that gravitational torques, and not pressure gradients, inject the orbiting mass. However, the way this mass is distributed in orbit is affected by the equation of state and the choice of rock material, the Tillotson equation for granite giving slightly larger mean orbital radius for the particles left in orbit than the ANEOS dunite for the same impact parameter. We also find, compared to Paper II, that in all subsequent cases the new SPH code leads to a slightly less extended prelunar accretion disk. We think this is

  5. Oxygen isotope constraints on the origin of impact glasses from the cretaceous-tertiary boundary

    SciTech Connect

    Blum, J.D.; Chamberlain, C.P. )

    1992-08-21

    Laser-extraction oxygen isotope and major element analyses of individual glass spherules from Haitian Cretaceous-Tertiary boundary sediments demonstrate that the glasses fall on a mixing line between an isotopically heavy ({delta}{sup 18}O = 14 per mil) high-calcium composition and an isotopically light ({delta}{sup 18}O = 6 per mil) high-silicon composition. This trend can be explained by melting of heterogeneous source rocks during the impact of an asteroid (or comet) {approximately}65 million years ago. The data indicate that the glasses are a mixture of carbonate and silicate rocks and exclude derivation of the glasses either by volcanic processes or as mixtures of sulfate-high evaporate and silicate rocks.

  6. The origin of the moon and the single-impact hypothesis III.

    PubMed

    Benz, W; Cameron, A G; Melosh, H J

    1989-01-01

    In previous papers in this series the smoothed particle hydrodynamics method (SPH) has been used to explore the conditions in which a major planetary collision may have been responsible for the formation of the Moon. In Paper II (W. Benz, W.L. Slattery, and A.G.W. Cameron 1987, Icarus 71, 30-45) it was found that the optimum conditions were obtained when the mass ratio of the impactor to the protoearth was 0.136. In the present paper we investigate the importance of the equation of state by running this optimum case several times and varying the equation of state and other related parameters. The two equations of state compared are the Tillotson (used in the previous papers) and the CHART D/CSQ ANEOS. Because of differences in these equations of state, including the fact that different types of rocks were used in association with each, it was not possible to prepare initial planetary models that were comparable in every respect, so several different simulations were necessary in which different planetary parameters were matched between the equations of state. We also used a new version of the SPH code. The results reaffirmed the previous principal conclusions: the collisions produced a disk of rocky material in orbit, with most of the material derived from the impacting object. These results indicate that the equation of state is not a critical factor in determining the amount of material thrown into orbit. This confirms the conclusions of Paper II that gravitational torques, and not pressure gradients, inject the orbiting mass. However, the way this mass is distributed in orbit is affected by the equation of state and the choice of rock material, the Tillotson equation for granite giving slightly larger mean orbital radius for the particles left in orbit than the ANEOS dunite for the same impact parameter. We also find, compared to Paper II, that in all subsequent cases the new SPH code leads to a slightly less extended prelunar accretion disk. We think this is

  7. Impact origin of the Avak Structure, Arctic Alaska, and genesis of the Barrow gas fields

    USGS Publications Warehouse

    Kirschner, C.E.; Grantz, A.; Mullen, M.W.

    1992-01-01

    Geophysical and subsurface geologic data suggest that the Avak structure, which underlies the Arctic Coastal Plain 12 km southeast of Barrow, Alaska, is a hypervelocity meteorite or comet impact structure. The structure is a roughly circular area of uplifted, chaotically deformed Upper Triassic to Lower Cretaceous sedimentary rocks 8 km in diameter that is bounded by a ring of anastomosing, inwardly dipping, listric normal faults 12 km in diameter. Examination of cores from the Barrow gas fields and data concerning the age of the Avak structure suggest that the Avak meteorite struck a Late Cretaceous or Tertiary marine shelf or coastal plain between the Cenomanian (ca. 95 Ma), and deposition of the basal beds of the overlying late Pliocene and Quaternary Gubik Formation (ca. 3 Ma). -from Authors

  8. Impact origin of the Avak structure, Arctic Alaska, and genesis of the Barrow gas fields

    SciTech Connect

    Kirschner, C.E.; Grantz, A. )

    1990-05-01

    Geophysical and subsurface geologic data confirm that the Avak structure, which underlies the coastal plain 12 km southeast of Barrow, is an impact crater. The structure is a roughly circular area of chaotically deformed Upper Triassic to Lower Cretaceous sedimentary rocks 8 km in diameter bounded by a ring of anastomozing, inwardly dipping, listric normal faults. Beyond the ring, these rocks are almost flat. Basement is strongly deformed Ordovician and Silurian argillite. Strong density and seismic velocity contrast between the argillite and the overlying strata produce gravity and seismic reflection signatures that define ring anticlines around the disturbed zone and a structural high at its center. The Mesozoic strata are about 760 m thick in the adjacent Barrow gas fields, where the Neocomian pebble shale unit and the gas-producing Lower Jurassic Barrow sandstone lie at average subsea depths of 438 m and 670 m, respectively. In the Avak well, drilled on the central high, the pebble shale unit and Barrow sandstone lie near the surface, documenting more than 500 m of uplift at the high. The cores in this well also show steep dips (30-90{degree}), abundant tectonic breccia with argillite clasts 90 m above basement, fractured quartz grains, and shatter cones resembling those found in well-documented meteorite craters. Stratigraphic data suggest that the Avak meteorite struck a late Early Cretaceous marine shelf, produced peripheral highs that trapped gas in the Barrow fields, and triggered massive landslides on the adjacent outer shelf. The age of the landslides dates the impact at about 105 Ma.

  9. Framing choice: The origins and impact of consumer rhetoric in US health care debates.

    PubMed

    Lee, Nancy S

    2015-08-01

    This paper examines the origins of consumerist discourse in health care from a communication perspective via a historical textual analysis of health writing in popular magazines from 1930 to 1949. The focus is on Consumers Union's Consumer Reports and the American Medical Association's lay health magazine, Hygeia. Findings from Consumer Reports show that the consumer movement of the 1930s-40s staunchly advocated for universal health insurance. Whereas consumer rights language nowadays tends towards individual choice and personal responsibility, consumerism in health care during that era articulated ideas about consumer citizenship, framing choice and responsibility in collectivist terms and health care as a social good. This paper also illuminates the limits and weaknesses of a central tenet in consumerism-freedom of choice-by analyzing stories in Hygeia about the doctor-patient relationship. A textual analysis finds that the AMA's justification in the 1930s-40s against socialized medicine, i.e., the freedom to choose a doctor, was in practice highly controlled by the medical profession. Findings show that long before the rhetoric of the "empowered consumer" became popular, some patients exercised some choice even in an era when physicians achieved total professional dominance. But these patients were few and tend to occupy the upper socioeconomic strata of US society. In reality choice was an illusion in a fee-for-service era when most American families could not afford the costs of medical care. PMID:26093071

  10. Framing choice: The origins and impact of consumer rhetoric in US health care debates.

    PubMed

    Lee, Nancy S

    2015-08-01

    This paper examines the origins of consumerist discourse in health care from a communication perspective via a historical textual analysis of health writing in popular magazines from 1930 to 1949. The focus is on Consumers Union's Consumer Reports and the American Medical Association's lay health magazine, Hygeia. Findings from Consumer Reports show that the consumer movement of the 1930s-40s staunchly advocated for universal health insurance. Whereas consumer rights language nowadays tends towards individual choice and personal responsibility, consumerism in health care during that era articulated ideas about consumer citizenship, framing choice and responsibility in collectivist terms and health care as a social good. This paper also illuminates the limits and weaknesses of a central tenet in consumerism-freedom of choice-by analyzing stories in Hygeia about the doctor-patient relationship. A textual analysis finds that the AMA's justification in the 1930s-40s against socialized medicine, i.e., the freedom to choose a doctor, was in practice highly controlled by the medical profession. Findings show that long before the rhetoric of the "empowered consumer" became popular, some patients exercised some choice even in an era when physicians achieved total professional dominance. But these patients were few and tend to occupy the upper socioeconomic strata of US society. In reality choice was an illusion in a fee-for-service era when most American families could not afford the costs of medical care.

  11. Nature, Origin, Potential Composition, and Climate Impact of the Asian Tropopause Aerosol Layer (ATAL)

    NASA Technical Reports Server (NTRS)

    Fairlie, T. D.; Vernier, J.-P.; Thomason, L. W.; Natarajan, M.; Bedka, K.; Wienhold, F.; Bian J.; Martinsson, B.

    2015-01-01

    Satellite observations from SAGE II and CALIPSO indicate that summertime aerosol extinction has more than doubled in the Asian Tropopause Aerosol Layer (ATAL) since the late 1990s. Here we show remote and in-situ observations, together with results from a chemical transport model (CTM), to explore the likely composition, origin, and radiative forcing of the ATAL. We show in-situ balloon measurements of aerosol backscatter, which support the high levels observed by CALIPSO since 2006. We also show in situ measurements from aircraft, which indicate a predominant carbonaceous contribution to the ATAL (Carbon/Sulfur ratios of 2- 10), which is supported by the CTM results. We show that the peak in ATAL aerosol lags by 1 month the peak in CO from MLS, associated with deep convection over Asia during the summer monsoon. This suggests that secondary formation and growth of aerosols in the upper troposphere on monthly timescales make a significant contribution to ATAL. Back trajectory calculations initialized from CALIPSO observations provide evidence that deep convection over India is a significant source for ATAL through the vertical transport of pollution to the upper troposphere.

  12. Obesity in emerging nations: evolutionary origins and the impact of a rapid nutrition transition.

    PubMed

    Prentice, Andrew M

    2009-01-01

    Here we explore whether there is any evidence that the rapid development of the obesity epidemic in emerging nations, and its unusual coexistence with malnutrition, may have evolutionary origins that make such populations especially vulnerable to the obesogenic conditions accompanying the nutrition transition. It is concluded that any selection of so-called 'thrifty genes' is likely to have affected most races due to the frequency and ubiquity of famines and seasonal food shortages in ancient populations. Although it remains a useful stimulus for research, the thrifty gene hypothesis remains a theoretical construct that so far lacks any concrete examples. There is currently little evidence that the ancestral genomes of native Asian or African populations carry particular risk alleles for obesity. Interestingly, however, there is evidence that a variant allele of the FTO gene that favors leanness may be less active in Asians or Africans. There is also some evidence that Caucasians may be less prone to developing type 2 diabetes mellitus than other races suggesting that there has been recent selection of protective alleles. In the near future, recently developed statistical methods for comparing genome-wide data across populations are likely to reveal or refute the presence of any thrifty genes and might indicate mechanisms of vulnerability. PMID:19346767

  13. The origin, global distribution, and functional impact of the human 8p23 inversion polymorphism.

    PubMed

    Salm, Maximilian P A; Horswell, Stuart D; Hutchison, Claire E; Speedy, Helen E; Yang, Xia; Liang, Liming; Schadt, Eric E; Cookson, William O; Wierzbicki, Anthony S; Naoumova, Rossi P; Shoulders, Carol C

    2012-06-01

    Genomic inversions are an increasingly recognized source of genetic variation. However, a lack of reliable high-throughput genotyping assays for these structures has precluded a full understanding of an inversion's phylogenetic, phenotypic, and population genetic properties. We characterize these properties for one of the largest polymorphic inversions in man (the ∼4.5-Mb 8p23.1 inversion), a structure that encompasses numerous signals of natural selection and disease association. We developed and validated a flexible bioinformatics tool that utilizes SNP data to enable accurate, high-throughput genotyping of the 8p23.1 inversion. This tool was applied retrospectively to diverse genome-wide data sets, revealing significant population stratification that largely follows a clinal "serial founder effect" distribution model. Phylogenetic analyses establish the inversion's ancestral origin within the Homo lineage, indicating that 8p23.1 inversion has occurred independently in the Pan lineage. The human inversion breakpoint was localized to an inverted pair of human endogenous retrovirus elements within the large, flanking low-copy repeats; experimental validation of this breakpoint confirmed these elements as the likely intermediary substrates that sponsored inversion formation. In five data sets, mRNA levels of disease-associated genes were robustly associated with inversion genotype. Moreover, a haplotype associated with systemic lupus erythematosus was restricted to the derived inversion state. We conclude that the 8p23.1 inversion is an evolutionarily dynamic structure that can now be accommodated into the understanding of human genetic and phenotypic diversity.

  14. Origin and history of chondrite regolith, fragmental and impact-melt breccias from Spain

    NASA Technical Reports Server (NTRS)

    Casanova, I.; Keil, K.; Wieler, R.; San Miguel, A.; King, E. A.

    1990-01-01

    Six ordinary chondrite breccias from the Museo Nacional de Ciencias Naturales, Madrid (Spain), are described and classified as follows: the solar gas-rich regolith breccia Oviedo (H5); the premetamorphic fragmental breccias Cabezo de Mayo (type 6, L-LL), and Sevilla (LL4); the fragmental breccias Canellas (H4) and Gerona (H5); and the impact melt breccia, Madrid (L6). It is confirmed that chondrites with typical light-dark structures and petrographic properties typical of regolith breccias may (Oviedo) or may not (Canellas) be solar gas-rich. Cabezo de Mayo and Sevilla show convincing evidence that they were assembled prior to peak metamorphism and were equilibrated during subsequent reheating. Compositions of olivine and low-Ca pyroxene in host chondrite and breccia clasts in Cabezo de Mayo are transitional between groups L and LL. It is suggested, based on mineralogic and oxygen isotopic compositions of host and clasts, that the rock formed on the L parent body by mixing, prior to peak metamorphism. This was followed by partial equilibrium of two different materials: the indigenous L chondrite host and exotic LL melt rock clasts.

  15. Origin and history of chondrite regolith, fragmental and impact-melt breccias from Spain

    NASA Astrophysics Data System (ADS)

    Casanova, I.; Keil, K.; Wieler, R.; San Miguel, A.; King, E. A.

    1990-06-01

    Six ordinary chondrite breccias from the Museo Nacional de Ciencias Naturales, Madrid (Spain), are described and classified as follows: the solar gas-rich regolith breccia Oviedo (H5); the premetamorphic fragmental breccias Cabezo de Mayo (type 6, L-LL), and Sevilla (LL4); the fragmental breccias Canellas (H4) and Gerona (H5); and the impact melt breccia, Madrid (L6). It is confirmed that chondrites with typical light-dark structures and petrographic properties typical of regolith breccias may (Oviedo) or may not (Canellas) be solar gas-rich. Cabezo de Mayo and Sevilla show convincing evidence that they were assembled prior to peak metamorphism and were equilibrated during subsequent reheating. Compositions of olivine and low-Ca pyroxene in host chondrite and breccia clasts in Cabezo de Mayo are transitional between groups L and LL. It is suggested, based on mineralogic and oxygen isotopic compositions of host and clasts, that the rock formed on the L parent body by mixing, prior to peak metamorphism. This was followed by partial equilibrium of two different materials: the indigenous L chondrite host and exotic LL melt rock clasts.

  16. Impact origin of sediments at the Opportunity landing site on Mars.

    PubMed

    Knauth, L Paul; Burt, Donald M; Wohletz, Kenneth H

    2005-12-22

    Mars Exploration Rover Opportunity discovered sediments with layered structures thought to be unique to aqueous deposition and with minerals attributed to evaporation of an acidic salty sea. Remarkable iron-rich spherules were ascribed to later groundwater alteration, and the inferred abundance of water reinforced optimism that Mars was once habitable. The layered structures, however, are not unique to water deposition, and the scenario encounters difficulties in accounting for highly soluble salts admixed with less soluble salts, the lack of clay minerals from acid-rock reactions, high sphericity and near-uniform sizes of the spherules and the absence of a basin boundary. Here we present a simple alternative explanation involving deposition from a ground-hugging turbulent flow of rock fragments, salts, sulphides, brines and ice produced by meteorite impact. Subsequent weathering by intergranular water films can account for all of the features observed without invoking shallow seas, lakes or near-surface aquifers. Layered sequences observed elsewhere on heavily cratered Mars and attributed to wind, water or volcanism may well have formed similarly. If so, the search for past life on Mars should be reassessed accordingly. PMID:16372001

  17. Moon and Terrestrial Planets: Unresolved Questions

    NASA Astrophysics Data System (ADS)

    Schmitt, H. H.

    2002-12-01

    Human exploration during Apollo began the documentation of the evolution of the Moon and of its importance in understanding the origin and evolution of the terrestrial planets. This revolution in planetary geology continues as a vigorous and vibrant arena for discovery and debate for new generations of geoscientists. Although much has been learned and, indeed, resolved in lunar science, we are left with major questions unresolved. One fundamental question is that of the origin of the Moon. A large consensus has developed in the planetary science community that the Moon was created by the "giant impact" of a Mars-sized asteroid on the Earth after the accretion of the Earth was largely complete and differentiation had begun. A minority, however, questions this consensus hypothesis because of increasing indications that the lower mantle of the Moon may be largely undifferentiated. If the issue of the high angular momentum of the Earth-Moon system can be resolved through new modeling studies, then capture of a co-orbiting planetesimal may be an important alternative to a "giant impact". Another important question, particularly in consideration of the terrestrial and Martian surface environments during the first 0.8 billion years of Earth history, is the impact record of that period as recorded on the Moon. Again, a large consensus has developed that the 50 or so large and very large impact basins identified on the Moon were created over a very short "cataclysm" between about 3.9 and 3.8 billion years ago. Here also, a minority suggests that this period of large basin formation, although distinct in lunar history, took place over several hundred million years and that the apparent cataclysm is an artifact of sampling the effects of the last few basin-forming impacts. Either way, a previously unavailable source of impactors appeared somewhere in the solar system and greatly affected terrestrial environments at the time the precursors to life were appearing on Earth

  18. Beware Answers with Questions

    ERIC Educational Resources Information Center

    Humble, Steve

    2005-01-01

    Answers to mathematical problems come in all forms and most come with a variety of questions. Students often forget to ask questions once they have found an answer. This paper suggests that students would always benefit by questioning answers.

  19. Carbonates in fractures of Martian meteorite Allan Hills 84001: petrologic evidence for impact origin

    NASA Technical Reports Server (NTRS)

    Scott, E. R.; Krot, A. N.; Yamaguchi, A.

    1998-01-01

    Carbonates in Martian meteorite Allan Hills 84001 occur as grains on pyroxene grain boundaries, in crushed zones, and as disks, veins, and irregularly shaped grains in healed pyroxene fractures. Some carbonate disks have tapered Mg-rich edges and are accompanied by smaller, thinner and relatively homogeneous, magnesite microdisks. Except for the microdisks, all types of carbonate grains show the same unique chemical zoning pattern on MgCO3-FeCO3-CaCO3 plots. This chemical characteristic and the close spatial association of diverse carbonate types show that all carbonates formed by a similar process. The heterogeneous distribution of carbonates in fractures, tapered shapes of some disks, and the localized occurrence of Mg-rich microdisks appear to be incompatible with growth from an externally derived CO2-rich fluid that changed in composition over time. These features suggest instead that the fractures were closed as carbonates grew from an internally derived fluid and that the microdisks formed from a residual Mg-rich fluid that was squeezed along fractures. Carbonate in pyroxene fractures is most abundant near grains of plagioclase glass that are located on pyroxene grain boundaries and commonly contain major or minor amounts of carbonate. We infer that carbonates in fractures formed from grain boundary carbonates associated with plagiociase that were melted by impact and dispersed into the surrounding fractured pyroxene. Carbonates in fractures, which include those studied by McKay et al. (1996), could not have formed at low temperatures and preserved mineralogical evidence for Martian organisms.

  20. Neighbour Origin and Ploidy Level Drive Impact of an Alien Invasive Plant Species in a Competitive Environment

    PubMed Central

    Sun, Yan; Müller-Schärer, Heinz; Schaffner, Urs

    2016-01-01

    Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids, allo-polycarpic tetraploids). However, only tetraploids have been found in its introduced range in North America, where C. stoebe has become a most prominent plant invader. Here, we focus on the ploidy level of C. stoebe and origin of neighbouring community in explaining the high impact during the invasion of new sites in the introduced range. We conducted a mesocosm experiment under open-field conditions with the diploid (EU2x) and tetraploid (EU4x) cytotype of Centaurea stoebe from its native European (EU) range, and with the invasive tetraploid (NA4x) cytotype from the introduced North American (NA) range in competition with EU (old) or NA (new) neighbouring plant communities. In the presence of competition, the biomass of EU neighbouring community was reduced to a comparable level by all three geo-cytotypes of C. stoebe. In contrast, the biomass of the NA neighbouring community was reduced beyond when competing with tetraploid, but not with diploid C. stoebe. The fact that the biomass of all three geo-cytotypes of C. stoebe was correlated with the biomass of the EU neighbouring community, but not with that of the NA neighbouring community suggests that different mechanisms underlie the competitive interactions between C. stoebe and its old vs. new neighbouring communities, such as competition for the same limiting resources at home vs competition through novel allelo-chemicals or differential resource uptake strategies in the introduced range. We therefore caution to simply use the ecosystem impact assessed at home to predict impact in the introduced range. PMID:27203687

  1. Neighbour Origin and Ploidy Level Drive Impact of an Alien Invasive Plant Species in a Competitive Environment.

    PubMed

    Sun, Yan; Müller-Schärer, Heinz; Schaffner, Urs

    2016-01-01

    Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids, allo-polycarpic tetraploids). However, only tetraploids have been found in its introduced range in North America, where C. stoebe has become a most prominent plant invader. Here, we focus on the ploidy level of C. stoebe and origin of neighbouring community in explaining the high impact during the invasion of new sites in the introduced range. We conducted a mesocosm experiment under open-field conditions with the diploid (EU2x) and tetraploid (EU4x) cytotype of Centaurea stoebe from its native European (EU) range, and with the invasive tetraploid (NA4x) cytotype from the introduced North American (NA) range in competition with EU (old) or NA (new) neighbouring plant communities. In the presence of competition, the biomass of EU neighbouring community was reduced to a comparable level by all three geo-cytotypes of C. stoebe. In contrast, the biomass of the NA neighbouring community was reduced beyond when competing with tetraploid, but not with diploid C. stoebe. The fact that the biomass of all three geo-cytotypes of C. stoebe was correlated with the biomass of the EU neighbouring community, but not with that of the NA neighbouring community suggests that different mechanisms underlie the competitive interactions between C. stoebe and its old vs. new neighbouring communities, such as competition for the same limiting resources at home vs competition through novel allelo-chemicals or differential resource uptake strategies in the introduced range. We therefore caution to simply use the ecosystem impact assessed at home to predict impact in the introduced range. PMID:27203687

  2. Neighbour Origin and Ploidy Level Drive Impact of an Alien Invasive Plant Species in a Competitive Environment.

    PubMed

    Sun, Yan; Müller-Schärer, Heinz; Schaffner, Urs

    2016-01-01

    Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids, allo-polycarpic tetraploids). However, only tetraploids have been found in its introduced range in North America, where C. stoebe has become a most prominent plant invader. Here, we focus on the ploidy level of C. stoebe and origin of neighbouring community in explaining the high impact during the invasion of new sites in the introduced range. We conducted a mesocosm experiment under open-field conditions with the diploid (EU2x) and tetraploid (EU4x) cytotype of Centaurea stoebe from its native European (EU) range, and with the invasive tetraploid (NA4x) cytotype from the introduced North American (NA) range in competition with EU (old) or NA (new) neighbouring plant communities. In the presence of competition, the biomass of EU neighbouring community was reduced to a comparable level by all three geo-cytotypes of C. stoebe. In contrast, the biomass of the NA neighbouring community was reduced beyond when competing with tetraploid, but not with diploid C. stoebe. The fact that the biomass of all three geo-cytotypes of C. stoebe was correlated with the biomass of the EU neighbouring community, but not with that of the NA neighbouring community suggests that different mechanisms underlie the competitive interactions between C. stoebe and its old vs. new neighbouring communities, such as competition for the same limiting resources at home vs competition through novel allelo-chemicals or differential resource uptake strategies in the introduced range. We therefore caution to simply use the ecosystem impact assessed at home to predict impact in the introduced range.

  3. An original experiment to determine impact of catch crop introduction in a crop rotation on N2O production fate

    NASA Astrophysics Data System (ADS)

    Tallec, Tiphaine; Le Dantec, Valérie; Zawilski, Bartosz; Brut, Aurore; Boussac, Marion; Ferlicoq, Morgan; Ceschia, Eric

    2015-04-01

    The raise in N2O concentration from the preindustrial era (280 ppb) to nowadays (324 ppb) is estimated to account for approximately 6% of the predicted global warming (IPCC 2014). Worldwide, soils are considered to be the dominant source of N2O, releasing an estimated 9.5 Tg N2O-N y-1 (65% of global N2O emissions), of which 36.8% are estimated to originate from agricultural soils (IPCC 2001). Most N2O originating from agricultural soils is a by- or end-product of nitrification or denitrification. The fate of N2O produced by microbiological processes in the subsoil is controlled by biotic (crop species, occurring soil organic matter, human pressure via mineral and organic nitrogen fertilisation) and abiotic (environmental conditions such as temperature, soil moisture, pH, etc.) factors. In cropland, contrary to forest and grassland, long bare soil periods can occurred between winter and summer crops with a high level of mineral (fertilizer) and organic (residues) nitrogen remaining in the soil, causing important emissions of carbon and nitrogen induced by microbial activities. Introduction of catch crop has been identified as an important mitigation option to reduce environmental impact of crops mainly thanks to their ability to increase CO2 fixation, to decrease mineral nitrogen lixiviation and also reduce the potential fate of N2O production. Uncertainty also remains about the impact of released mineral nitrogen coming from crushed catch crop on N2O production if summer crop seedling and mineral nitrogen release are not well synchronized. To verify those assumptions, a unique paired-plot experiment was carried in the south-west of France from September 2013 to august 2014 to test impact of management change on N2O budget and production dynamic. A crop plot was divided into two subplots, one receiving a catch crop (mustard), the other one remaining conventionally managed (bare-soil during winter). This set-up allowed avoiding climate effect. Each subplot was

  4. MinUrals: Mineral resources of the Urals -- origin, development, and environmental impact

    NASA Astrophysics Data System (ADS)

    Leistel, J. M.; Minurals Team

    2003-04-01

    The MinUrals project (supported by the European Commission under the 5th F.P.- INCO2 - contract ICA2-CT-2000-10011) is focusing on the South Urals mining sector, in order to improve local socio-economic conditions, through: 1) The reinterpretation of the geodynamics of South Urals and of the different types of ore deposits and the development of tools for mineral exploration (new geophysical and geochemical technology). The convergence setting and the formation of arc, fore-arc and back-arc systems explain the volcano-sedimentary and structural features. This geodynamic setting largely controls the distribution and characteristics of the different types of mineralisation; 2) The evaluation of local mining-related risks to the environment, with a development of methodologies for assessing and reducing the environmental impact and localizing areas of high metal potential/low environmental constraints. Three pilote sites were investigated: Sibay and Uchaly (with mining installations), and Karabash (with mining installations and smelter); 3) The implementation of a Geographical Information System taking into account the mineral potential and the environmental constraints that, through data ranking and combining the key parameters of the areas with high metal potential and environmental constraints, will enable the production of a Mineral Potential and Environmental Constraints Map of the South Urals; 4) The elaboration of recommendations for a suitable environmentally-aware mining-industry legislation, based on a comparison with the European legislation, to be adressed to the Commission on the demarcation of powers and subjects between the federal government, governments of the subjects of the Russian Federation and local authorities. More information can be found on the project web sites [http://minurals.brgm.fr] or [http://www.nhm.ac.uk/mineralogy/minurals/minurals.htm] or [http://www.anrb.ru/geol/MinUrals] or [http://minurals.ilmeny.ac.ru] MinUrals Team (*): Aug

  5. Evaluating the Long-Term Health and Economic Impacts of Central Residential Air Filtration for Reducing Premature Mortality Associated with Indoor Fine Particulate Matter (PM2.5) of Outdoor Origin

    PubMed Central

    Zhao, Dan; Azimi, Parham; Stephens, Brent

    2015-01-01

    Much of human exposure to fine particulate matter (PM2.5) of outdoor origin occurs in residences. High-efficiency particle air filtration in central heating, ventilating, and air-conditioning (HVAC) systems is increasingly being used to reduce concentrations of particulate matter inside homes. However, questions remain about the effectiveness of filtration for reducing exposures to PM2.5 of outdoor origin and adverse health outcomes. Here we integrate epidemiology functions and mass balance modeling to estimate the long-term health and economic impacts of HVAC filtration for reducing premature mortality associated with indoor PM2.5 of outdoor origin in residences. We evaluate 11 classifications of filters (MERV 5 through HEPA) using six case studies of single-family home vintages and ventilation system combinations located in 22 U.S. cities. We estimate that widespread use of higher efficiency filters would reduce premature mortality by 0.002–2.5% and increase life expectancy by 0.02–1.6 months, yielding annual monetary benefits ranging from $1 to $1348 per person in the homes and locations modeled herein. Large differences in the magnitude of health and economic impacts are driven largely by differences in rated filter efficiency and building and ventilation system characteristics that govern particle infiltration and persistence, with smaller influences attributable to geographic location. PMID:26197328

  6. Evaluating the Long-Term Health and Economic Impacts of Central Residential Air Filtration for Reducing Premature Mortality Associated with Indoor Fine Particulate Matter (PM2.5) of Outdoor Origin.

    PubMed

    Zhao, Dan; Azimi, Parham; Stephens, Brent

    2015-07-21

    Much of human exposure to fine particulate matter (PM2.5) of outdoor origin occurs in residences. High-efficiency particle air filtration in central heating, ventilating, and air-conditioning (HVAC) systems is increasingly being used to reduce concentrations of particulate matter inside homes. However, questions remain about the effectiveness of filtration for reducing exposures to PM2.5 of outdoor origin and adverse health outcomes. Here we integrate epidemiology functions and mass balance modeling to estimate the long-term health and economic impacts of HVAC filtration for reducing premature mortality associated with indoor PM2.5 of outdoor origin in residences. We evaluate 11 classifications of filters (MERV 5 through HEPA) using six case studies of single-family home vintages and ventilation system combinations located in 22 U.S. cities. We estimate that widespread use of higher efficiency filters would reduce premature mortality by 0.002-2.5% and increase life expectancy by 0.02-1.6 months, yielding annual monetary benefits ranging from $1 to $1348 per person in the homes and locations modeled herein. Large differences in the magnitude of health and economic impacts are driven largely by differences in rated filter efficiency and building and ventilation system characteristics that govern particle infiltration and persistence, with smaller influences attributable to geographic location.

  7. Evaluating the Long-Term Health and Economic Impacts of Central Residential Air Filtration for Reducing Premature Mortality Associated with Indoor Fine Particulate Matter (PM2.5) of Outdoor Origin.

    PubMed

    Zhao, Dan; Azimi, Parham; Stephens, Brent

    2015-07-01

    Much of human exposure to fine particulate matter (PM2.5) of outdoor origin occurs in residences. High-efficiency particle air filtration in central heating, ventilating, and air-conditioning (HVAC) systems is increasingly being used to reduce concentrations of particulate matter inside homes. However, questions remain about the effectiveness of filtration for reducing exposures to PM2.5 of outdoor origin and adverse health outcomes. Here we integrate epidemiology functions and mass balance modeling to estimate the long-term health and economic impacts of HVAC filtration for reducing premature mortality associated with indoor PM2.5 of outdoor origin in residences. We evaluate 11 classifications of filters (MERV 5 through HEPA) using six case studies of single-family home vintages and ventilation system combinations located in 22 U.S. cities. We estimate that widespread use of higher efficiency filters would reduce premature mortality by 0.002-2.5% and increase life expectancy by 0.02-1.6 months, yielding annual monetary benefits ranging from $1 to $1348 per person in the homes and locations modeled herein. Large differences in the magnitude of health and economic impacts are driven largely by differences in rated filter efficiency and building and ventilation system characteristics that govern particle infiltration and persistence, with smaller influences attributable to geographic location. PMID:26197328

  8. Posing Einstein's Question: Questioning Einstein's Pose.

    ERIC Educational Resources Information Center

    Topper, David; Vincent, Dwight E.

    2000-01-01

    Discusses the events surrounding a famous picture of Albert Einstein in which he poses near a blackboard containing a tensor form of his 10 field equations for pure gravity with a question mark after it. Speculates as to the content of Einstein's lecture and the questions he might have had about the equation. (Contains over 30 references.) (WRM)

  9. Assessing the public health impact of developmental origins of health and disease (DOHaD) nutrition interventions.

    PubMed

    Garmendia, Maria Luisa; Corvalan, Camila; Uauy, Ricardo

    2014-01-01

    Investing in the maternal and early-infancy periods (the first 1,000 days, i.e. from -1 to +2 years) is presently acknowledged as a key priority to ensure good nutrition and prevent all forms of malnutrition. The concept is to invest during this period to maximize the human development potential, and the early-life agenda includes prevention of stunting and promotion of optimal brain development as well as ensuring the quality of life of those who survive. Thus, public health assessments of specific interventions need to go beyond the traditional indices of prevention of death and disease. We need to consider including a full range of outcomes such as disability-adjusted life years (DALY) and quality-adjusted life years (QALY) and not only the number of deaths. The long-term outcomes of maternal and infant interventions to prevent obesity and related noncommunicable diseases remain uncertain in terms of their biological impact even under ideal conditions (efficacy); we need interventions with proven effectiveness under real-world conditions (effectiveness). Conversely, interventions to prevent undernutrition have already been proven effective and are considered cost-effective based on rigorous economic analyses. Continuous evaluation of interventions implemented using the developmental origins of health and disease (DOHaD) model needs to be undertaken, as this will allow progressive improvement and thus maximize the potential impact on the health and well-being of populations. We need to consider the population-attributable risk of obesity and chronic disease and conduct an economic evaluation of the lifelong impact of chronic diseases not only in terms of lives lost but also in relation to lost DALY and QALY. This should help to prioritize preventive actions in line with patterns of disease and disability considering the existing resources and demands.

  10. Gay-Straight Alliances: Understanding Their Impact on the Academic and Social Experiences of Lesbian, Gay, Bisexual, Transgender, and Questioning High School Students

    ERIC Educational Resources Information Center

    McCormick, Adam; Schmidt, Kathryn; Clifton, Emily

    2015-01-01

    Few studies have examined the effectiveness of gay-straight alliances (GSAs) on the social and academic experiences of lesbian, gay, bisexual, transgender, and questioning (LGBTQ) youths. The limited research on GSAs suggests that they are associated with positive youth development and increased safety; however, little qualitative information…

  11. Questioning the Role of Internationalization in the Nationalization of Higher Education: The Impact of the EU TEMPUS Programme on Higher Education in Syria

    ERIC Educational Resources Information Center

    Ayoubi, Rami M.; Massoud, Hiba K.

    2011-01-01

    Given the need for major reform of the higher education programmes in Syria, and answering the voices that question the role of European Union (EU) in assisting the development of the higher education sector, this study presents an analysis of the contribution of (TEMPUS) Programme in modernising higher education in Syria. The study compares the…

  12. Measuring victimization inside prisons: questioning the questions.

    PubMed

    Wolff, Nancy; Jing Shi; Bachman, Ronet

    2008-10-01

    Violence and victimization inside the prison setting are accepted as facts, although the facts about their prevalence remain uncertain. Variation in the methods used to estimate rates of sexual and physical victimization contribute to the wide range in estimates appearing in the prison literature. This article focuses on the questions used in the prison victimization literature to elicit information on victimization from inmates, compared to questions used in the general victimization literature. The questions used in the National Violence Against Women and Men Surveys are used to estimate sexual and physical victimization rates for an entire prison system. Rates of victimization were found to vary significantly by specificity of the question, definition of perpetrator, and clustering of behaviors. Facts about victimization inside prison will become more certain when the methodology becomes more standardized and consistent with definitions of victimization. PMID:18309042

  13. Samples from Martian craters: Origin of the Martian soil by hydrothermal alteration of impact melt deposits and atmospheric interactions with ejecta during crater formation

    NASA Technical Reports Server (NTRS)

    Newsom, Horton E.

    1988-01-01

    The origin of the Martian soil is an important question for understanding weathering processes on the Martian surface, and also for understanding the global geochemistry of Mars. Chemical analyses of the soil will provide an opportunity to examine what may be a crustal average, as studies of loess on the Earth have demonstrated. In this regard the origin of the Martian soil is also important for understanding the chemical fractionations that have affected the composition of the soil. Several processes that are likely to contribute to the Martian soil are examined.

  14. Eukaryotic origins.

    PubMed

    Lake, James A

    2015-09-26

    The origin of the eukaryotes is a fundamental scientific question that for over 30 years has generated a spirited debate between the competing Archaea (or three domains) tree and the eocyte tree. As eukaryotes ourselves, humans have a personal interest in our origins. Eukaryotes contain their defining organelle, the nucleus, after which they are named. They have a complex evolutionary history, over time acquiring multiple organelles, including mitochondria, chloroplasts, smooth and rough endoplasmic reticula, and other organelles all of which may hint at their origins. It is the evolutionary history of the nucleus and their other organelles that have intrigued molecular evolutionists, myself included, for the past 30 years and which continues to hold our interest as increasingly compelling evidence favours the eocyte tree. As with any orthodoxy, it takes time to embrace new concepts and techniques.

  15. Eukaryotic origins

    PubMed Central

    Lake, James A.

    2015-01-01

    The origin of the eukaryotes is a fundamental scientific question that for over 30 years has generated a spirited debate between the competing Archaea (or three domains) tree and the eocyte tree. As eukaryotes ourselves, humans have a personal interest in our origins. Eukaryotes contain their defining organelle, the nucleus, after which they are named. They have a complex evolutionary history, over time acquiring multiple organelles, including mitochondria, chloroplasts, smooth and rough endoplasmic reticula, and other organelles all of which may hint at their origins. It is the evolutionary history of the nucleus and their other organelles that have intrigued molecular evolutionists, myself included, for the past 30 years and which continues to hold our interest as increasingly compelling evidence favours the eocyte tree. As with any orthodoxy, it takes time to embrace new concepts and techniques. PMID:26323753

  16. Late Quaternary seismo-stratigraphy of Lake Wanapitei, Sudbury, Ontario, Canada: Arguments for a possible meteorite impact origin

    NASA Astrophysics Data System (ADS)

    Lazorek, Michael; Eyles, Nick; Eyles, Carolyn; Doughty, Mike; L'Heureux, Elizabeth; Milkereit, Berndt

    2006-12-01

    Lake Wanapitei (132.75 km2) fills what has been identified as an Eocene (c. 37 Ma) meteorite impact basin in the Canadian Shield near Sudbury, Ontario, Canada. The area was glaciated many times during the Pleistocene and the basin lies immediately north of the prominent Cartier Moraine built during the last glaciation by the retreating Laurentide Ice Sheet some 11,000 years ago. Study of the deeper geophysics of the basin using magnetic and gravity techniques, and confirmation of its origin, is hampered by lack of data regarding water depths, the form of the bedrock surface and the thickness and character of glacial and postglacial sediment. To this end, more than 300 km of high-resolution single channel seismic chirp and 200 kHz bathymetric data were collected from the basin in the summer of 2002. Water depths reach a maximum of 118 m and acoustic basement is defined by a glacially scoured bedrock surface. The overlying Pleistocene sediment fill exceeds 35 m in thickness and consists of a lowermost late-glacial succession of rhythmically laminated silty clays deposited when the basin was flooded by a deep and regionally extensive ice dammed water body (Glacial Lake Algonquin). Truncation of the upper surface of this succession across large parts of the lake floor records the drainage of Lake Algonquin and the isolation of Wanapitei Lake as a separate water body. Overlying Holocene sediment is up to 10 m thick but is markedly discontinuous and commonly occurs as mounded ‘drifts’ reflecting strong bottom currents and low inputs of modern sediment. The presence of apparently undisturbed Precambrian bedrock below large portions of the lake basin places significant constraints on the dimensions of any meteorite impact structure.

  17. Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules: an inventory for the origins of life.

    PubMed

    Chyba, C; Sagan, C

    1992-01-01

    Sources of organic molecules on the early Earth divide into three categories: delivery by extraterrestrial objects; organic synthesis driven by impact shocks; and organic synthesis by other energy sources (such as ultraviolet light or electrical discharges). Estimates of these sources for plausible end-member oxidation states of the early terrestrial atmosphere suggest that the heavy bombardment before 3.5 Gyr ago either produced or delivered quantities of organics comparable to those produced by other energy sources. Which sources of prebiotic organics were quantitatively dominant depends strongly on the composition of the early terrestrial atmosphere. In the event of an early strongly reducing atmosphere, production by atmospheric shocks seems to have dominated that due to electrical discharges. Organic synthesis by ultraviolet light may, in turn, have dominated shock production, but only if a long-wavelength absorber such as H2S were supplied to the atmosphere at a rate sufficient for synthesis to have been limited by ultraviolet flux, rather than by reactant abundance. In the apparently more likely case of an early terrestrial atmosphere of intermediate oxidation state, atmospheric shocks were probably of little importance for direct organic production. For [H2]/[CO2] ratios of approximately 0.1, net organic production was some three orders of magnitude lower than for reducing atmospheres, with delivery of intact exogenous organics in interplanetary dust particles (IDPs) and ultraviolet production being the most important sources. At still lower [H2]/[CO2] ratios, IDPs may have been the dominant source of prebiotic organics on the early Earth. Endogenous, exogenous and impact-shock sources of organics could each have made a significant contribution to the origins of life.

  18. Questions about Adoption

    MedlinePlus

    ... Español Text Size Email Print Share Questions About Adoption Page Content Article Body What's the best way to handle my child's questions about her adoption? Many parents want to know when is the ...

  19. Burning Questions about Calories.

    ERIC Educational Resources Information Center

    Keller, J. David; Berry, Kimberly A.

    2001-01-01

    Uses questioning techniques to teach about caloric consumption and weight gain. Starts with defining questions about calories and includes the stages of measuring calories, analyzing data, and conducting inquiry research. Includes directions for the experiment. (YDS)

  20. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Alexander, John J.

    1979-01-01

    Describes an exam question which challenges college freshmen, enrolled in chemistry, to derive temperature dependence of an equilibrium constant. The question requires cognitive response at the level of synthesis. (Author/SA)

  1. Does the sedimentology of the Chelmsford formation provide evidence for a meteorite impact origin of the Sudbury structure?

    NASA Technical Reports Server (NTRS)

    Long, D. G. F.

    1992-01-01

    The post-'event' fill of the Paleoproterozoic Sudbury Basin consists of at least 600 m of deep-water mudrocks of the Onwatin Formation, overlain by 850 m of lithic-arkosic muddy sandstones in the Chelmsford Formation. While mudstones of the Onwatin reflect deposition in a deep-water, anoxic setting, there is no clear evidence of local breccias, conglomerates, or sand bodies to support the concept that the basin was protected by the steep walls of an impact crater. Carbonates in the basal, Vermillion Member are of sedimentary exhalitive origin and were not derived from a shallow marine shelf. Turbidites in the Chelmsford Formation show no evidence of centripetal fill as might be expected from a restricted, circular basin. They appear to have been emplaced by predominantly southwesterly flowing turbidity currents, which showed little to no deflection along the depositional axis of an elongate foreland basin that developed in front of the rising Penokean mountain chain. While the presence of minor sandstone-filled fractures in parts of the Chelmsford Formation suggests the presence of north- or south-directed paleoslopes, no evidence is seen to support the existence of subbasins or a central uplift within the Sudbury Basin. While tilt-corrected paleocurrent orientations are ambiguous, due to postdepositional shortening of strata during cleavage development, strain correction of the observations makes little difference to the net, south-southwest-directed paleoflow.

  2. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Alexander, John J., Ed.

    1987-01-01

    Contains two articles relating to chemistry examination questions. One provides examples of how to sequence multiple choice questions so that partial credit may be given for some responses. The second includes a question and solution dealing with stereoisomerism as a result of free radical chlorination of a nonstereoisometic substance. (TW)

  3. Improving Student Question Classification

    ERIC Educational Resources Information Center

    Heiner, Cecily; Zachary, Joseph L.

    2009-01-01

    Students in introductory programming classes often articulate their questions and information needs incompletely. Consequently, the automatic classification of student questions to provide automated tutorial responses is a challenging problem. This paper analyzes 411 questions from an introductory Java programming course by reducing the natural…

  4. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Alexander, John J., Ed.

    1983-01-01

    Acceptable answers are provided for two chemistry questions. The first question is related to the prediction of the appearance of non-first-order proton nuclear magnetic resonance (NMR) spectra. The second question is related to extraterrestrial kinetic theory of gases. (JN)

  5. Reading for Meaning: Questioning

    ERIC Educational Resources Information Center

    Trinkle, Catherine

    2009-01-01

    An essential literacy skill is asking questions. Because reading comprehension strategies should be taught directly and explicitly, students need to be told that they should ask questions throughout their research and that all questions are valid. While library media specialists are not reading teachers, the work they do with students in the…

  6. Questions for Surveys

    PubMed Central

    Schaeffer, Nora Cate; Dykema, Jennifer

    2011-01-01

    We begin with a look back at the field to identify themes of recent research that we expect to continue to occupy researchers in the future. As part of this overview, we characterize the themes and topics examined in research about measurement and survey questions published in Public Opinion Quarterly in the past decade. We then characterize the field more broadly by highlighting topics that we expect to continue or to grow in importance, including the relationship between survey questions and the total survey error perspective, cognitive versus interactional approaches, interviewing practices, mode and technology, visual aspects of question design, and culture. Considering avenues for future research, we advocate for a decision-oriented framework for thinking about survey questions and their characteristics. The approach we propose distinguishes among various aspects of question characteristics, including question topic, question type and response dimension, conceptualization and operationalization of the target object, question structure, question form, response categories, question implementation, and question wording. Thinking about question characteristics more systematically would allow study designs to take into account relationships among these characteristics and identify gaps in current knowledge. PMID:24970951

  7. Making Questions Flow

    ERIC Educational Resources Information Center

    Rothstein, Dan; Santana, Luz; Minigan, Andrew P.

    2015-01-01

    Getting students to ask questions can feel like pulling teeth. How can teachers transform that feeling and create classrooms that come alive with questions? The authors, developers of the question formulation technique, suggest two simple changes: First, teachers need to give students both a structure and the opportunity to practice generating…

  8. Teachers' Classroom Questions

    ERIC Educational Resources Information Center

    Sahin, Alpaslan

    2007-01-01

    There is a large body of literature on the types of questions asked by teachers. Questions are a way that teachers use to bring students around to the correct mathematical concepts and procedures through "the negotiation of meaning for necessary condition of learning" (Voigt, 1992, p. 43). Teachers ask many questions, but we are not sure what…

  9. Measuring Victimization inside Prisons: Questioning the Questions

    ERIC Educational Resources Information Center

    Wolff, Nancy; Shi, Jing; Bachman, Ronet

    2008-01-01

    Violence and victimization inside the prison setting are accepted as facts, although the facts about their prevalence remain uncertain. Variation in the methods used to estimate rates of sexual and physical victimization contribute to the wide range in estimates appearing in the prison literature. This article focuses on the questions used in the…

  10. Beginning EFL Teachers' Beliefs about Quality Questions and Their Questioning Practices

    ERIC Educational Resources Information Center

    Pham, Ly Ngoc Khanh; Hamid, M. Obaidul

    2013-01-01

    Motivated by the scarcity of research that examines the impact of teacher beliefs on their actual practices in Vietnam, this study investigated the relationship between teachers' beliefs about quality questions and their questioning behaviours in terms of questioning purposes, content focus, students' cognitive level, wording and syntax.…

  11. IMPACT REGIMES AND POST-FORMATION SEQUESTRATION PROCESSES: IMPLICATIONS FOR THE ORIGIN OF HEAVY NOBLE GASES IN TERRESTRIAL PLANETS

    SciTech Connect

    Mousis, Olivier; Petit, Jean-Marc; Picaud, Sylvain; Thomas, Caroline; Schmitt, Bernard

    2010-05-10

    The difference between the measured atmospheric abundances of neon, argon, krypton, and xenon for Venus, Earth, and Mars is striking. Because these abundances drop by at least 2 orders of magnitude as one moves outward from Venus to Mars, the study of the origin of this discrepancy is a key issue that must be explained if we are to fully understand the different delivery mechanisms of the volatiles accreted by the terrestrial planets. In this work, we aim to investigate whether it is possible to quantitatively explain the variation of the heavy noble gas abundances measured on Venus, Earth, and Mars, assuming that cometary bombardment was the main delivery mechanism of these noble gases to the terrestrial planets. To do so, we use recent dynamical simulations that allow the study of the impact fluxes of comets upon the terrestrial planets during the course of their formation and evolution. Assuming that the mass of noble gases delivered by comets is proportional to the rate at which they collide with the terrestrial planets, we show that the krypton and xenon abundances in Venus and Earth can be explained in a manner consistent with the hypothesis of cometary bombardment. In order to explain the krypton and xenon abundance differences between Earth and Mars, we need to invoke the presence of large amounts of CO{sub 2}-dominated clathrates in the Martian soil that would have efficiently sequestered these noble gases. Two different scenarios based on our model can also be used to explain the differences between the neon and argon abundances of the terrestrial planets. In the first scenario, cometary bombardment of these planets would have occurred at epochs contemporary with the existence of their primary atmospheres. Comets would have been the carriers of argon, krypton, and xenon, while neon would have been gravitationally captured by the terrestrial planets. In the second scenario, we consider impacting comets that contained significantly smaller amounts of argon

  12. Discovery of microscopic evidence for shock metamorphism at the Serpent Mound structure, south-central Ohio: Confirmation of an origin by impact

    USGS Publications Warehouse

    Carlton, R.W.; Koeberl, C.; Baranoski, M.T.; SchuMacHer, G.A.

    1998-01-01

    The origin of the Serpent Mound structure in south-central Ohio has been disputed for many years. Clearly, more evidence was needed to resolve the confusion concerning the origin of the Serpent Mound feature either by endogenic processes or by hypervelocity impact. A petrographic study of 21 samples taken from a core 903 m long drilled in the central uplift of the structure provides evidence of shock metamorphism in the form of multiple sets of planar deformation features in quartz grains, as well as the presence of clasts of altered impact-melt rock. Crystallographic orientations of the planar deformation features show maxima at the shock-characteristic planes of {101??3} and {101??2} and additional maxima at {101??1}, {213??1}, and {516??1}. Geochemical analyses of impact breccias show minor enrichments in the abundances of the siderophile elements Cr, Co, Ni, and Ir, indicating the presence of a minor meteoritic component.

  13. Unpark Those Questions

    ERIC Educational Resources Information Center

    Ness, Molly

    2013-01-01

    Whenever Mr. Henderson's 3rd grade students had a question that he couldn't immediately answer or that seemed off-topic, he asked them to write the question on a sticky note and place it on a poster dubbed the "Parking Lot." His intention was to find time later to answer those questions, but too often, he said, the parking lot…

  14. Risk Factor Analysis and the Youth Question

    ERIC Educational Resources Information Center

    France, Alan

    2008-01-01

    This paper is concerned with exploring how in late modernity the "youth question" is being addressed by public policy and what impact this is having on understandings of childhood and youth. Historically the youth question has been shaped by adult anxieties over youth delinquency and their problems of social integration. In late modernity, this is…

  15. Problem of Questioning

    SciTech Connect

    2005-10-31

    Le Prof.Leprince-Ringuet, chercheur sur le plan scientifique, artistique et humain, parle de la remise en question des hommes et la remise en question scientifique fondamentale ou exemplaire- plusieurs personnes prennent la parole p.ex Jeanmairet, Adam, Gregory. Le Prof.Gregory clot la soirée en remerciant le Prof.Leprince-Ringuet

  16. Questioning the Text.

    ERIC Educational Resources Information Center

    Ditor, Rachel

    2003-01-01

    Outlines a dramaturg's process when working on three different plays. Contends that the myriad variations on the question "what will happen next?" serve as the basic architecture on which the dynamic relationship between the story/storytellers and the audience is built. Observes that the continual planning and answering of questions is story. (PM)

  17. Designing Great Hinge Questions

    ERIC Educational Resources Information Center

    Wiliam, Dylan

    2015-01-01

    According to author Dylan Wiliam, because lessons never go exactly as planned, teachers should build plan B into plan A. This involves designing a lesson with a "hinge" somewhere in the middle and using specific kinds of questions--what he calls hinge questions--to quickly assess students' understanding of a concept before moving on.…

  18. Problem of Questioning

    ScienceCinema

    None

    2016-07-12

    Le Prof.Leprince-Ringuet, chercheur sur le plan scientifique, artistique et humain, parle de la remise en question des hommes et la remise en question scientifique fondamentale ou exemplaire- plusieurs personnes prennent la parole p.ex Jeanmairet, Adam, Gregory. Le Prof.Gregory clot la soirée en remerciant le Prof.Leprince-Ringuet

  19. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Alexander, John J., Ed.

    1988-01-01

    Describes three examination questions which could be used in college chemistry courses. Discusses each problem and gives acceptable solutions. Problems include: "A Multi-Topic Problem for General Chemistry"; "Consumption of Air by Biuret Reagent--a Question Involving Experimental Design"; and "An Instructive Problem in Heterogeneous Equilibrium."…

  20. Are There Any Questions?

    ERIC Educational Resources Information Center

    Dauterman, Philip

    1970-01-01

    The crucial variable in good classroom teaching is the verbal behavior of the teacher. Through his questioning techniques--what questions he asks, how and when he asks them, how he replies to students, and how he stimulates students to reply to each other--the teacher can evoke a high level of class discussion and force students to go beyond the…

  1. Questions About the Oceans.

    ERIC Educational Resources Information Center

    Dubach, Harold W.; Taber, Robert W.

    This book was prompted by the success of a display mounted by the National Oceanographic Data Center at the 17th International Science Fair in 1966, which enabled visiting teachers and students to ask and receive answers to questions via teletype. The book contains one hundred questions typical of those asked, together with answers ranging in…

  2. 1 Great Question

    ERIC Educational Resources Information Center

    Nethery, Carrie

    2011-01-01

    In this article, the author presents an ideal question that can take an art teacher and his or her students through all the levels of thought in Bloom's taxonomy--perfect for modeling the think-aloud process: "How many people is the artist inviting into this picture?" This great question always helps the students look beyond the obvious and dig…

  3. Questionable measures are pretty meaningless.

    PubMed

    Brown, Nicholas J L; Wong, Paul T P

    2015-09-01

    Comments on the original article "Life is pretty meaningful," by S. J. Heintzelman and L. A. King (see record 2014-03265-001). Heintzelman and King argued that meaning in life (MIL) is widely experienced and exists at high levels. In this brief commentary, the current authors examine what they believe are several flaws in their argument: a lack of clarity in defining MIL; the questionable validity of the instruments used to measure MIL throughout Heintzelman and King's article; and an erroneous interpretation of quantitative reports of MIL from surveys and the academic literature.

  4. “A question of balance”: addressing the public health impacts of multinational enterprises in the OECD Guidelines for Multinational Enterprises

    PubMed Central

    Yang, Joshua S.; McDaniel, Patricia A.; Malone, Ruth E.

    2012-01-01

    Background The global community is beginning to address non-communicable diseases, but how to increase the accountability of multinational enterprises (MNEs) for the health impacts of their products and practices remains unclear. We examine the Organization for Economic Cooperation and Development’s (OECD) efforts to do so through voluntary MNE guidelines. Methods We developed a historical case study of how the OECD Guidelines for Multinational Enterprises were developed and revised from 1973–2000 through an analysis of publicly available archived OECD and tobacco industry documents. Results The first edition of the Guidelines was a purely economic instrument. Outside pressures and a desire to ward off more stringent regulatory efforts resulted in the addition over time of guidelines related to the environment, consumer interests, sustainable development, and human rights. Conclusion Despite their voluntary nature, the Guidelines can play a role in efforts to help balance the interests of MNEs and public health by providing a starting point for efforts to create binding provisions addressing MNEs’ contributions to disease burden or disease reduction. PMID:23046298

  5. What is a Question?

    NASA Technical Reports Server (NTRS)

    Knuth, Kevin H.; Clancy, Daniel (Technical Monitor)

    2002-01-01

    A given question can be defined in terms of the set of statements or assertions that answer it. Application of the logic of inference to this set of assertions allows one to derive the logic of inquiry among questions. There are interesting symmetries between the logics of inference and inquiry; where probability describes the degree to which a premise implies an assertion, there exists an analogous quantity that describes the bearing or relevance that a question has on an outstanding issue. These have been extended to suggest that the logic of inquiry results in functional relationships analogous to, although more general than, those found in information theory. Employing lattice theory, I examine in greater detail the structure of the space of assertions and questions demonstrating that the symmetries between the logical relations in each of the spaces derive directly from the lattice structure. Furthermore, I show that while symmetries between the spaces exist, the two lattices are not isomorphic. The lattice of assertions is described by a Boolean lattice 2(sup N) whereas the lattice of real questions is shown to be a sublattice of the free distributive lattice FD(N) = 2(sup 2(sup N)). Thus there does not exist a one-to-one mapping of assertions to questions, there is no reflection symmetry between the two spaces, and questions in general do not possess unique complements. Last, with these lattice structures in mind, I discuss the relationship between probability, relevance and entropy.

  6. How Deep is the Critical Zone: A Scientific Question with Potential Impact For Decision-makers in Areas of Shale-Gas Development and Hydraulic Fracturing

    NASA Astrophysics Data System (ADS)

    Brantley, S. L.

    2014-12-01

    Citizens living in areas of shale-gas development such as the Marcellus gas play in Pennsylvania and surrounding states are cognizant of the possibility that drilling and production of natural gas -- including hydraulic fracturing -- may have environmental impacts on their water. The Critical Zone is defined as the zone from vegetation canopy to the lower limits of groundwater. This definition is nebulous in terms of the lower limit, and yet, defining the bottom of the Critical Zone is important if citizens are to embrace shale-gas development. This is because, although no peer-reviewed study has been presented that documents a case where hydraulic fracturing or formation fluids have migrated upwards from fracturing depths to drinking water resources, a few cases of such leakage have been alleged. On the other hand, many cases of methane migration into aquifers have been documented to occur and some have been attributed to shale-gas development. The Critical Zone science community has a role to play in understanding such contamination problems, how they unfold, and how they should be ameliorated. For example, one big effort of the Critical Zone science community is to promote sharing of data describing the environment. This data effort has been extended to provide data for citizens to understand water quality by a team known as the Shale Network. As scientists learn to publish data online, these efforts must also be made accessible to non-scientists. As citizens access the data, the demand for data will grow and all branches of government will eventually respond by providing more accessible data that will help the public and policy-makers make decisions.

  7. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Alexander, John J.

    1980-01-01

    Provides exam questions and solutions for a problem in amplification sequence of reactions, and a problem in applying group theory techniques and making spectral assignments and structural determination by qualitative arguments in the bonding in metal complexes. (CS)

  8. Rubella: Questions and Answers

    MedlinePlus

    ... of special precautions. Does the MMR vaccine cause autism? There is no scientific evidence that measles, MMR, ... other vaccine causes or increases the risk of autism. The question about a possible link between MMR ...

  9. Biology Today: Questions & Variations.

    ERIC Educational Resources Information Center

    Flannery, Maura, Ed.

    1988-01-01

    Discusses the importance of student questions as tools of instruction and as indicators of student misconceptions. Suggests different ways in which students may gain an understanding of biological concepts through discussion of popular movies and biological problems. (CW)

  10. Managing Affect in Learners' Questions in Undergraduate Science

    ERIC Educational Resources Information Center

    Pedrosa-de-Jesus, Helena; Watts, Mike

    2014-01-01

    This article aims to position students' classroom questioning within the literature surrounding affect and its impact on learning. The article consists of two main sections. First, the act of questioning is discussed in order to highlight how affect shapes the process of questioning, and a four-part genesis to question-asking that we call…

  11. Impact of Scientific Versus Emotional Wording of Patient Questions on Doctor-Patient Communication in an Internet Forum: A Randomized Controlled Experiment with Medical Students

    PubMed Central

    Bientzle, Martina; Griewatz, Jan; Küppers, Julia; Cress, Ulrike; Lammerding-Koeppel, Maria

    2015-01-01

    Background Medical expert forums on the Internet play an increasing role in patient counseling. Therefore, it is important to understand how doctor-patient communication is influenced in such forums both by features of the patients or advice seekers, as expressed in their forum queries, and by characteristics of the medical experts involved. Objective In this experimental study, we aimed to examine in what way (1) the particular wording of patient queries and (2) medical experts’ therapeutic health concepts (for example, beliefs around adhering to a distinctly scientific understanding of diagnosis and treatment and a clear focus on evidence-based medicine) impact communication behavior of the medical experts in an Internet forum. Methods Advanced medical students (in their ninth semester of medical training) were recruited as participants. Participation in the online forum was part of a communication training embedded in a gynecology course. We first measured their biomedical therapeutic health concept (hereinafter called “biomedical concept”). Then they participated in an online forum where they answered fictitious patient queries about mammography screening that either included scientific or emotional wording in a between-group design. We analyzed participants’ replies with regard to the following dimensions: their use of scientific or emotional wording, the amount of communicated information, and their attempt to build a positive doctor-patient relationship. Results This study was carried out with 117 medical students (73 women, 41 men, 3 did not indicate their sex). We found evidence that both the wording of patient queries and the participants’ biomedical concept influenced participants’ response behavior. They answered emotional patient queries in a more emotional way (mean 0.92, SD 1.02) than scientific patient queries (mean 0.26, SD 0.55; t 74=3.48, P<.001, d=0.81). We also found a significant interaction effect between participants’ use of

  12. Lunar Geoscience: Key Questions for Future Lunar Exploration

    NASA Astrophysics Data System (ADS)

    Head, James

    2014-05-01

    Lunar Geoscience: Key Questions for Future Lunar Exploration James W. Head, Department of Geological Sciences, Brown University, Providence, RI 02912 USA. (Invited paper/solicited talk for EGU 2014 PS2.3 Lunar session, Bernard H. Foing, Convener EGU PS2.3) The last several decades of intensive robotic exploration of the Moon has built on early Apollo and Luna exploration to provide fundamental knowledge of Earth's satellite and an excellent perspective on the most well-documented planetary body other than Earth. This new planetological perspective has raised substantial new questions about the nature of the origin of the Moon, its early differentiation and bombardment history, its internal thermal evolution, the production of its secondary crust as exemplified by the lunar maria, and tertiary crust as potentially seen in steep-sided domes and impact melt differentiates, the abundance of interior volatiles and their role in volcanic eruptions, and the abundance of surface volatiles and their concentration in polar regions. On the basis of this new information, a series of specific outstanding geoscience questions can be identified that can serve as guides for future human and robotic exploration. These include: 1) What is the nature and abundance of impact melt seas and what rock types do they produce upon differentiation and solidification? 2) Where are lunar mantle samples located on the lunar surface and what processes are responsible for placing them there? 3) What processes are responsible for producing the silica-rich viscous domes, such as those seen at Gruithuisen? 4) What are the volatile species involved in the emplacement of lunar pyroclastic deposits and what clues do they provide about deep magmatic volatiles and shallow volatile formation processes? 5) How do we account for the differing characteristics of regional dark mantling pyroclastic deposits? 6) When did mare basalt volcanism begin (earliest cryptmaria) and how and where is it manifested? 7

  13. Sources of clasts in terrestrial impact melts - Clues to the origin of LKFM. [Low-K Fra Mauro

    NASA Technical Reports Server (NTRS)

    Mccormick, K. A.; Taylor, G. J.; Keil, K.; Spudis, P. D.; Grieve, R. A. F.

    1989-01-01

    Low-K Fra Mauro (LKFM) 'basalt', which is found exclusively as an impact melt rock, cannot be modeled geochemically from its clast population or from any combination of known pristine lunar rock types. To clarify clast/melt relationships, a study was made of impact melt rocks from Mistastin Lake crater, Labrador, where there are only three target rocks: anorthosite, quartz monzonite, and granodiorite. Feldspar compositions in these rocks define distinct fields on the An-Ab-Or ternary diagram, making it possible to identify the source of each feldspar clast. Clasts in the Mistastin impact melts do not reflect the abundance of target rocks melted during the impact. The abundance of anorthosite in the clast population varies from 34 to 100 percent compared to a relatively constant value of 65 percent calculated to be in the melt matrix. Therefore the clasts appear to be derived predominantly from material relatively far removed from the zone of impact melting. Melt-matrix composition is dictated strictly by the composition of the target materials within a small radius around and below the point of impact. This suggests that the LKFM composition was derived from a lower crustal source.

  14. Question answering for biology.

    PubMed

    Neves, Mariana; Leser, Ulf

    2015-03-01

    Biologists often pose queries to search engines and biological databases to obtain answers related to ongoing experiments. This is known to be a time consuming, and sometimes frustrating, task in which more than one query is posed and many databases are consulted to come to possible answers for a single fact. Question answering comes as an alternative to this process by allowing queries to be posed as questions, by integrating various resources of different nature and by returning an exact answer to the user. We have surveyed the current solutions on question answering for Biology, present an overview on the methods which are usually employed and give insights on how to boost performance of systems in this domain.

  15. Impact of parental Bos taurus and Bos indicus origins on copy number variation in traditional Chinese cattle breeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copy number variation (CNV) is an important component of genomic structural variation and plays a role not only in evolutionary diversification but also domestication. Chinese cattle were derived from Bos taurus and Bos indicus, and several breeds presumably are of hybrid origin, but the evolution o...

  16. Impact of Primary and Secondary Social Origin Factors on the Transition to University in the Czech Republic

    ERIC Educational Resources Information Center

    Simonová, Natalie; Soukup, Petr

    2015-01-01

    The main objective of this paper is to show to what extent and why students with the same academic aptitude but different social backgrounds have different odds of entering university. For our analysis, we separated primary and secondary factors of social origin in the formation of educational inequalities. The results show that the primary and…

  17. Distribution, Origin, and Realtions to Flow of Salty Ground Water Along the Western Margin of the Chesapeake Bay Impact Structure in Eastern Virginia

    NASA Astrophysics Data System (ADS)

    McFarland, R.; Bruce, S.

    2002-05-01

    The Chesapeake Bay impact structure closely coincides with parts of some aquifers in eastern Virginia that contain saltwater as much as 30 miles landward of the coast. The impact structure has thereby been inferred to play some role in controlling the presence of this "inland saltwater wedge", which formed under unstressed conditions prior to present-day ground-water withdrawals. That the impact severely disrupted the previously stratified sediments casts doubt on conceptualizations of a regionally contiguous, vertically layered system of aquifers and confining units. In addition, large and increasing ground-water withdrawals have resulted in continuing water-level declines and altered flow directions that create the potential for saltwater intrusion. Hence, the origin and emplacement of the saltwater must be known to predict its reaction to stresses being placed upon the flow system. Specific conductances and concentrations of chloride in ground water along the western margin of the impact structure reflect a transitional interface between freshwater to the west and seawater to the east that coincides aerially with the margin of the impact structure. Ratios of bromide to chloride and chlorine-36 to total chloride, and of stable hydrogen and oxygen isotopes, indicate chloride to have originated primarily from mixing of freshwater and seawater across the interface. In addition, deep ground water east of the interface having specific conductances which exceed that of seawater likely resulted from partial evaporation of seawater, either (1) in restricted coastal environments under arid conditions, (2) by rapid vaporization caused by the impact event, and (or) (3) by residual heat and associated hydrothermal activity following the impact. Mixing of freshwater and seawater has been theorized to take place in a "differential flushing" manner that left residual seawater to form the saltwater wedge. Seawater emplaced during inundation of the land surface persisted around

  18. My Favorite Exam Question

    NASA Astrophysics Data System (ADS)

    Styer, Dan

    2015-12-01

    My favorite exam question comes from the final exam in an introductory mechanics course: A rolling 31 ton railroad boxcar collides with a stationary flatcar. The coupling mechanism activates so the cars latch together and roll down the track attached. Of the initial kinetic energy, 38% dissipates as heat, sound, vibrations, mechanical deformation, and so forth. How much does the flatcar weigh?

  19. Question: Who Can Vote?

    ERIC Educational Resources Information Center

    Rodeheaver, Misty D.; Haas, Mary E.

    2008-01-01

    This year's rollercoaster primary elections and the pending national election, with an anticipated record voter turnout, provide the perfect backdrop for an examination of the questions: (1) Who can vote?; and (2) Who will vote? Historically, the American government refused voting rights to various groups based on race, gender, age, and even…

  20. A Question of Character

    ERIC Educational Resources Information Center

    Stuart, Reginald

    2010-01-01

    When intern placement veteran Jacqueline Perkins begins counseling students at Florida A&M University (FAMU) about their prospects for getting well-paying, security-related jobs with the federal government, she confronts the 800-pound gorilla in the room--the question of whether a student has been convicted of or pleaded guilty to a misdemeanor.…

  1. My Favorite Exam Question

    ERIC Educational Resources Information Center

    Styer, Dan

    2015-01-01

    My favorite exam question comes from the final exam in an introductory mechanics course: "A rolling 31 ton railroad boxcar collides with a stationary flatcar. The coupling mechanism activates so the cars latch together and roll down the track attached. Of the initial kinetic energy, 38% dissipates as heat, sound, vibrations, mechanical…

  2. A Question of Choice

    PubMed Central

    2011-01-01

    Women's reproductive rights, reproductive health, and constitutional privacy rights in the United States are addressed in light of the contemporary onslaught of the Christian Right. The misuse of State power by fundamentalist social forces in America is critiqued. The article also briefly reviews the question of State control over women's bodies. PMID:21696627

  3. The Compensation Question

    ERIC Educational Resources Information Center

    Richwine, Jason; Biggs, Andrew; Mishel, Lawrence; Roy, Joydeep

    2012-01-01

    Over the past few years, as cash-strapped states and school districts have faced tough budget decisions, spending on teacher compensation has come under the microscope. The underlying question is whether, when you take everything into account, today's teachers are fairly paid, underpaid, or overpaid. In this forum, two pairs of respected…

  4. Exam Question Exchange.

    ERIC Educational Resources Information Center

    Alexander, John J., Ed.

    1978-01-01

    Two exam questions are presented. One suitable for advanced undergraduate or beginning graduate courses in organic chemistry, is on equivalent expressions for the description of several pericyclic reactions. The second, for general chemistry students, asks for an estimation of the rate of decay of a million-year-old Uranium-238 sample. (BB)

  5. Impact of length of cryopreservation and origin of cord blood units on hematologic recovery following cord blood transplantation.

    PubMed

    Kurita, N; Frassoni, F; Chiba, S; Podestà, M

    2015-06-01

    As the history of the cord blood banking system has lengthened, the number of cord blood units (CBUs) cryopreserved for years has increased. The global expansion of cord blood banking resulted in active international exchange of CBUs. To determine whether long-term cryopreservation and international shipment of CBUs affect the quality of the units and outcome after transplantation, we retrospectively analyzed the quality of 95 CBUs and the hematologic recovery of 127 patients with hematological malignancy following single-unit cord blood transplantation. Of the 127 CBUs used to transplant, 42 units were cryopreserved for long periods (5-11.8 years), and 44 units were shipped from distant countries. We found that length of cryopreservation and origin of CBUs did not affect the ratio of viable total-nucleated cells after thawing. Also, neutrophil engraftment was not affected by long-term cryopreservation (> 5 years) or origin (from distant countries), (hazard ratio, 0.91 and 1.2; P=0.65 and 0.41; respectively). The number of CD34(+) cells before freezing (> 1.4 cells/kg recipient) was the only factor that enhanced neutrophil engraftment (hazard ratio, 1.8; P<0.01). This suggests that length of cryopreservation and origin need not be prioritized over the CD34(+) cell dose when selecting CBUs.

  6. The great lunar hot spot and the composition and origin of the Apollo mafic (``LKFM'') impact-melt breccias

    NASA Astrophysics Data System (ADS)

    Korotev, Randy L.

    2000-02-01

    Thorium-rich, mafic impact-melt breccias from the Apollo 14-17 missions, that is, those breccias identified with the composition known as ``LKFM,'' are regarded largely as products of basin-forming impacts that penetrated the feldspathic crust and sampled underlying mafic material and magma-ocean residuum carrying the compositional signature of KREEP (potassium, rare earth elements, phosphorous). Despite considerable compositional variation among such breccias, compositions of all of them correspond to mixtures of only four components: (1) a norite with composition generally similar to that of Apollo 15 basalt (mean abundance: 58% range: ~30-95%), (2) Fo~90 dunite (mean: 13%, range: 1-27%), (3) feldspathic upper crust (mean: 29%, range: 4-50%), and FeNi metal (0.1-1.7%). Petrographic evidence has shown that much of the feldspathic component, but none of the KREEP component, is clastic. This observation and the high proportion of KREEP norite component in the breccias suggest that the melt zone of the impact or impacts forming the breccias contained little feldspathic material but consisted predominantly of material with the average composition of KREEP norite. The dunite component probably derives ultimately from the upper mantle. These conclusions support the hypothesis that the breccias were not formed in typical feldspathic crust but instead by one or more impacts into what is designated here ``the great lunar hot spot,'' that is, the anomalous Th-rich terrane in the Imbrium-Procellarum area identified by the Apollo and Lunar Prospector gamma-ray spectrometers. The LKFM composition is a special product of the great lunar hot spot and is not the average composition of the lower crust in typical feldspathic highlands. Similarly, Mg-suite and alkali-suite plutonic rocks of the Apollo collection are likely all differentiation products of the hot spot, not of plutons that might occur in typical feldspathic crust.

  7. Do Contaminants Originating from State-of-the-Art Treated Wastewater Impact the Ecological Quality of Surface Waters?

    PubMed Central

    Stalter, Daniel; Magdeburg, Axel; Quednow, Kristin; Botzat, Alexandra; Oehlmann, Jörg

    2013-01-01

    Since the 1980s, advances in wastewater treatment technology have led to considerably improved surface water quality in the urban areas of many high income countries. However, trace concentrations of organic wastewater-associated contaminants may still pose a key environmental hazard impairing the ecological quality of surface waters. To identify key impact factors, we analyzed the effects of a wide range of anthropogenic and environmental variables on the aquatic macroinvertebrate community. We assessed ecological water quality at 26 sampling sites in four urban German lowland river systems with a 0–100% load of state-of-the-art biological activated sludge treated wastewater. The chemical analysis suite comprised 12 organic contaminants (five phosphor organic flame retardants, two musk fragrances, bisphenol A, nonylphenol, octylphenol, diethyltoluamide, terbutryn), 16 polycyclic aromatic hydrocarbons, and 12 heavy metals. Non-metric multidimensional scaling identified organic contaminants that are mainly wastewater-associated (i.e., phosphor organic flame retardants, musk fragrances, and diethyltoluamide) as a major impact variable on macroinvertebrate species composition. The structural degradation of streams was also identified as a significant factor. Multiple linear regression models revealed a significant impact of organic contaminants on invertebrate populations, in particular on Ephemeroptera, Plecoptera, and Trichoptera species. Spearman rank correlation analyses confirmed wastewater-associated organic contaminants as the most significant variable negatively impacting the biodiversity of sensitive macroinvertebrate species. In addition to increased aquatic pollution with organic contaminants, a greater wastewater fraction was accompanied by a slight decrease in oxygen concentration and an increase in salinity. This study highlights the importance of reducing the wastewater-associated impact on surface waters. For aquatic ecosystems in urban areas this

  8. Big questions about the universe

    NASA Astrophysics Data System (ADS)

    Stavinschi, Magda

    2011-06-01

    Astronomy is not only a branch of science but also an important part of the culture and civilisations of peoples. Starting with archeoastronomy to the present day, it has always contributed to a better understanding of life, of humanity. After 400 years of modern astronomy, it still addresses major problems such as: Why there is something rather than nothing? Why is nature comprehensible to humans? How is cosmos related to humanity? Do multiverses exist? Is there life on other planets? Are we alone in the universe? Does the universe have a beginning? If so, what does it mean? How did the universe originate? All these questions are a challenge for interdisciplinary and transdisciplinary investigations, for philosophers, physicists, cosmologists, mathematicians, theologians. The new insights gained by pursuing in depth these common investigations will shape the society we live in and have important consequences on the future we are creating.

  9. Benedict Arnold: A Question of Honor.

    ERIC Educational Resources Information Center

    Nicolosi, Annie; O'Connell, Libby Haight; Rust, Mead

    2003-01-01

    The spring 2003 The Idea Book for Educators highlights television programming from the Arts and Entertainment Network (A&E), the History Channel, and the Biography Channel, with a focus on an A&E original movie premiere, "Benedict Arnold: A Question of Honor." The booklet contains the following materials: "A&E Study Guide: Benedict Arnold: A…

  10. Living in the question.

    PubMed

    Flower, J

    1999-01-01

    We live in a fast moving-world. Business has accelerated to breathtaking speeds in the 1990s--and in the last few years the afterburner has really kicked in. The speed of change is overwhelming. Especially in health care, who has time to "live in the question?" We need to decide things quickly, get the decision out of the way, and move on, right? Maybe. Biology shows us that you can't plan ahead very far. New things come along that you don't even have a category for, and therefore you don't even see them. Things are going to happen that you literally have no notion are even possible. The key to succeeding in this environment? Don't plan ahead. Stay curious. Make small bets. Build organizational hothouses. Feed the seedlings that grow. The challenge is to remain curious, to live in the question, both personally and organizationally.

  11. Questioning Many Mysteries

    NASA Astrophysics Data System (ADS)

    Martin, Sara F.

    2015-04-01

    The first section of this memoir queries my formative years. Indirectly I address the question, did my childhood and early years make a difference in my choice of career? Why and how did I begin my journey to becoming a scientist? Did I choose the field of solar astronomy or did circumstances dictate it for me? In the second section, I travel through my work environments and experiences, talking about interactions and aspects of being a scientist that do not appear in our research papers. What parts of my research were happenstances and what parts did I plan? What does it feel like to be on scientific quests? Using examples in my journey, I also turn to questions that have intrigued me throughout my sojourn as a solar astronomer. How do scientific discoveries come about? What factors lead to little discoveries? And what factors lead to major exciting discoveries? Are there timely questions we do not think to ask? How can small, seemingly scattered pieces of knowledge suddenly coalesce into a deeper understanding - what is called the "Aha!" experience - the times when our mental light switches on, and with child-like wonder we behold a "big picture"?

  12. Les questions de migrations internationales

    NASA Astrophysics Data System (ADS)

    Samman, Mouna Liliane

    1993-03-01

    International migrations have growing implications for both countries of origin and countries of destination. In the latter, the presence of foreigners and of members of their families today creates problems of integration, causes argument and brings mounting xenophobia. Paralleling political, economic and social measures taken by public authorities to respond to these difficulties, education needs to assist in defusing the resulting social tensions by preparing the minds of learners and helping to develop new attitudes. In particular, when educational programmes address questions of international migration, these should be treated in the framework of historical evolution so that their real significance and their true temporal and spatial dimensions become apparent. It is also important that the growing interdependence between countries should be made plain, that national history should be placed in its international context, and that the true consequences of these developments should be made clear. In this context, learners need to be acquainted with Human Rights, thereby stressing universal moral values and the role of the individual. Lastly, questions relating to international migration are usually presented in the media in a selective and partial manner, and the young people who take in this information often accept the hasty judgments which are made of situations as proven facts. This is why all teaching about international migration needs to be considered or reconsidered in the light of the complementary or competing actions of the media.

  13. Open questions in classical gravity

    SciTech Connect

    Mannheim, P.D. )

    1994-04-01

    In this work, the authors discuss some outstanding open questions regarding the validity and uniqueness of the standard second-order Newton-Einstein classical gravitational theory. On the observational side the authors discuss the degree to which the realm of validity of Newton's law of gravity can actually be extended to distances much larger than the solar system distance scales on which the law was originally established. On the theoretical side the authors identify some commonly accepted (but actually still open to question) assumptions which go into the formulation of the standard second-order Einstein theory in the first place. In particular, it is shown that while the familiar second-order Poisson gravitational equation (and accordingly its second-order covariant Einstein generalization) may be sufficient to yield Newton's law of gravity they are not in fact necessary. The standard theory thus still awaits the identification of some principle which would then make it necessary too. It is shown that current observational information does not exclusively mandate the standard theory, and that the conformal invariant fourth-order theory of gravity considered recently by Mannheim and Kazanas is also able to meet the constraints of data, and in fact to do so without the need for any so far unobserved nonluminous or dark matter. 37 refs., 7 figs.

  14. Early Archean Spherule Beds: Chromium Isotopes Confirm Origin Through Multiple Impacts of Projectiles of Carbonaceous Chondrite Type

    NASA Technical Reports Server (NTRS)

    Kyte, Frank T.; Shukolyukov, Alex; Lugmair, Guenter W.; Lowe, Donald R.; Byerly, Gary R.

    2003-01-01

    Three Early Archean spherule beds from Barberton, South Africa, have anomalous Cr isotope compositions in addition to large Ir anomalies, confirming the presence of meteoritic material with a composition similar to that in carbonaceous chondrites. The extra-terrestrial components in beds S2, S3, and S4 are estimated to be approx. l%, 50% - 60%, and 15% - 30%, respectively. These beds are probably the distal, and possibly global, ejecta from major large-body impacts. These impacts were probably much larger than the Cretaceous-Tertiary event, and all occurred over an interval of approx. 20 m.y., implying an impactor flux at 3.2 Ga that was more than an order of magnitude greater than the present flux.

  15. Asteroid impact vs. Deccan eruptions: The origin of low magnetic susceptibility beds below the Cretaceous-Paleogene boundary revisited

    NASA Astrophysics Data System (ADS)

    Abrajevitch, Alexandra; Font, Eric; Florindo, Fabio; Roberts, Andrew P.

    2015-11-01

    The respective roles of an asteroid impact and Deccan Traps eruptions in biotic changes at the Cretaceous-Paleogene (K-Pg) boundary are still debated. In many shallow marine sediments from around the world, the K-Pg boundary is marked by a distinct clay layer that is often underlain by a several decimeter-thick low susceptibility zone. A previous study of the Gubbio section, Italy (Lowrie et al., 1990), attributed low magnetization intensity in this interval to post-depositional dissolution of ferrimagnetic minerals. Dissolution was thought to be a consequence of downward infiltration of reducing waters that resulted from rapid accumulation of organic matter produced by mass extinctions after the K-Pg event. We compare the magnetic properties of sediments from the Gubbio section with those of the Bidart section in southern France. The two sections are similar in their carbonate lithology and the presence of a boundary clay and low susceptibility zone. When compared to background Cretaceous sediments, the low susceptibility zone in both sections is marked by an absence of biogenic magnetite, a decrease in total ferrimagnetic mineral content, and a preferential loss of magnetite with respect to hematite - features that are consistent with reductive dissolution. However, unlike the Gubbio section, where the low susceptibility zone starts immediately below the boundary clay, the low susceptibility zone and the clay layer at Bidart are separated by a ∼4-cm carbonate interval that contains abundant biogenic magnetite. Such separation casts doubt on a causal link between the impact and sediment bleaching. More likely, the low susceptibility layer marks a different environmental event that preceded the impact. An episode of increased atmospheric and oceanic acidity associated with Deccan Traps volcanism that occurred well before the K-Pg impact is argued here to account for the distinct magnetic properties of the low susceptibility intervals.

  16. The Answer Is the Question: The Effect of Verb Causality on Locus of Explanation.

    ERIC Educational Resources Information Center

    Semin, Gun R.; And Others

    1995-01-01

    Investigated how verb causality in question formulation affects the locus of causal origin for answers. Hypothesized questions formulated with action verbs cue the logical subject of the question sentence as the causal origin for answers. Reverse tendency was expected for state verbs. Verb type in question formulation was found to affect…

  17. A Question of Evidence

    ERIC Educational Resources Information Center

    Todd, Ross J.

    2008-01-01

    Broadly defined, evidence-based practice (EBP) is fundamentally about professional practice being informed and guided by best available evidence of what works. The EBP movement had its origins in the early 1990s in the United Kingdom in medicine and health care services. Sackett et al. defined evidence-based medicine as the "conscientious,…

  18. A Universe of Questions.

    ERIC Educational Resources Information Center

    Zeldovich, Yakov

    1992-01-01

    Reprinted from the original Russian manuscript of Yakov Zeldovich, this article chronicles his studies of the universe and his attempts to construct a theory of its evolution. He provides the high school student with compelling cosmological discussions about uniformity, galactic clusters, radiation, evolution, the big bang, and gravitational…

  19. The Art of Asking Questions.

    ERIC Educational Resources Information Center

    Sykes, Rosetta A.

    1979-01-01

    A rationale is given for the use of questioning techniques and strategies in classroom instruction. B. Bloom's Taxonomy of Educational Objectives is presented as one framework for questions. Five pitfalls, including avoiding vague questions and personal pronouns, are discussed. (CL)

  20. Outstanding questions: physics beyond the Standard Model.

    PubMed

    Ellis, John

    2012-02-28

    The Standard Model of particle physics agrees very well with experiment, but many important questions remain unanswered, among them are the following. What is the origin of particle masses and are they due to a Higgs boson? How does one understand the number of species of matter particles and how do they mix? What is the origin of the difference between matter and antimatter, and is it related to the origin of the matter in the Universe? What is the nature of the astrophysical dark matter? How does one unify the fundamental interactions? How does one quantize gravity? In this article, I introduce these questions and discuss how they may be addressed by experiments at the Large Hadron Collider, with particular attention to the search for the Higgs boson and supersymmetry. PMID:22253238

  1. Impact of information on intentions to vaccinate in a potential epidemic: Swine-origin Influenza A (H1N1).

    PubMed

    Chanel, Olivier; Luchini, Stéphane; Massoni, Sébastien; Vergnaud, Jean-Christophe

    2011-01-01

    Vaccination campaigns to prevent the spread of epidemics are successful only if the targeted populations subscribe to the recommendations of health authorities. However, because compulsory vaccination is hardly conceivable in modern democracies, governments need to convince their populations through efficient and persuasive information campaigns. In the context of the swine-origin A (H1N1) 2009 pandemic, we use an interactive study among the general public in the South of France, with 175 participants, to explore what type of information can induce change in vaccination intentions at both aggregate and individual levels. We find that individual attitudes to vaccination are based on rational appraisal of the situation, and that it is information of a purely scientific nature that has the only significant positive effect on intention to vaccinate.

  2. Early Archean Spherule Beds: Chromium Isotopes Confirm Origin through Multiple Impacts of Projectiles of Carbonaceous Chondrite Type: Comment and Reply

    NASA Technical Reports Server (NTRS)

    Kyte, Frank T.

    2003-01-01

    This is a exchange in the form of a comment and a reply in regards to an earlier article. The authors of the original article, consider it likely that virtually all of the projectile will condense with the silicate fraction, resulting in very little platinum group element fractionation in the final ejecta deposit. Further, we find no evidence in the commentator's, (i.e., Glikson), comment to support vapor fractionation. We note that the Pd/Ir ratios of published data on 2.56 Ga Hamersley Basin spherules are all greater than in chondrites, contrary to the assertion by Glikson. This is consistent with relatively high Pd concentrations (and Pd/Ir ratios) in crustal rocks.

  3. Geophysical anomalies and quartz microstructures, Eastern Warburton Basin, North-east South Australia: Tectonic or impact shock metamorphic origin?

    NASA Astrophysics Data System (ADS)

    Glikson, Andrew Y.; Uysal, I. Tonguç; Fitz Gerald, John D.; Saygin, Erdinc

    2013-03-01

    The Eastern Warburton Basin, Northeast South Australia, features major geophysical anomalies, including a magnetic high of near-200 nT centred on a 25 km-wide magnetic low (< 100 nT), interpreted in terms of a magmatic body below 6 km depth. A distinct seismic tomographic low velocity anomaly may reflect its thick (9.5 km) sedimentary section, high temperatures and possible deep fracturing. Scanning electron microscope (SEM) analyses of granites resolves microbreccia veins consisting of micron-scale particles injected into resorbed quartz grains. Planar and sub-planar elements in quartz grains (Qz/PE) occur in granites, volcanics and sediments of the > 30,000 km-large Eastern Warburton Basin. The Qz/PE include multiple intersecting planar to curved sub-planar elements with relic lamellae less than 2 μm wide with spacing of 4-5 μm. Qz/PE are commonly re-deformed, displaying bent and wavy patterns accompanied with fluid inclusions. U-stage measurements of a total of 243 planar sets in 157 quartz grains indicate dominance of ∏{10-12}, ω{10-13} and subsidiary §{11-22}, {22-41}, m{10-11} and x{51-61} planes. Transmission Electron Microscopy (TEM) analysis displays relic narrow ≤ 1 μm-wide lamellae and relic non-sub grain boundaries where crystal segments maintain optical continuity. Extensive sericite alteration of feldspar suggests hydrothermal alteration to a depth of 500 m below the unconformity which overlies the Qz/PE-bearing Warburton Basin terrain. The data are discussed in terms of (A) Tectonic-metamorphic deformation and (B) impact shock metamorphism producing planar deformation features (Qz/PDF). Deformed Qz/PE are compared to re-deformed Qz/PDFs in the Sudbury, Vredefort, Manicouagan and Charlevoix impact structures. A 4-5 km uplift of the Big Lake Granite Suite during 298-295 Ma is consistent with missing of upper Ordovician to Devonian strata and possible impact rebound. The occurrence of circular seismic tomography anomalies below the east

  4. The Origin and Impact of Ideals in eHealth Research: Experiences From the U-CARE Research Environment

    PubMed Central

    von Essen, Louise; Grönqvist, Helena

    2014-01-01

    Background The prevalence of information technology (IT) in society is a foundation for new modes of interaction between patients and health specialists. IT plays an important role in the renewal of care. Several countries have incorporated eHealth plans into their national health strategies. Part of the eHealth evolution concerns Internet psychological treatment and psychosocial care. These interventions are complex to design and evaluate due to legal, ethical, organizational, technical, and methodological challenges. Objective The objective of our study was to seek to make explicit contributions to the understanding of ideals in eHealth research, and illuminate their implications for establishing an effective research environment. Our analysis draws from three years of experience in establishing an eHealth research environment, and the literature. Methods We worked inductively to characterize challenging research ideals, and their origins, in our environment. Thereafter, we made a selective search of the literature to scrutinize and illuminate each ideal and it’s implications. Results In this work, we propose a structured approach to address ideals in eHealth research. The scrutinized ideals are accountability, innovation, rigor, relevance, and sustainability. The approach supports researchers to systematically understand the ideals, their origin, and to manage their implications within an eHealth research environment. Conclusions The complexity of eHealth research causes a need for sustainable, multi-disciplinary research environments. There is a need for a structured approach to organize eHealth research. The proposed approach helps to systematically scrutinize ideals, thus promoting high quality research. PMID:24860071

  5. Automatically classifying question types for consumer health questions.

    PubMed

    Roberts, Kirk; Kilicoglu, Halil; Fiszman, Marcelo; Demner-Fushman, Dina

    2014-01-01

    We present a method for automatically classifying consumer health questions. Our thirteen question types are designed to aid in the automatic retrieval of medical answers from consumer health resources. To our knowledge, this is the first machine learning-based method specifically for classifying consumer health questions. We demonstrate how previous approaches to medical question classification are insufficient to achieve high accuracy on this task. Additionally, we describe, manually annotate, and automatically classify three important question elements that improve question classification over previous techniques. Our results and analysis illustrate the difficulty of the task and the future directions that are necessary to achieve high-performing consumer health question classification.

  6. Generation, Propagation and Impact of Giant Tsunamis of Tectonic Origin in the Mediterranean Sea: Some Hints From Preliminary Scenario Studies

    NASA Astrophysics Data System (ADS)

    Tinti, S.; Armigliato, A.; Pagnoni, G.; Tonini, R.; Zaniboni, F.

    2006-12-01

    The recent catastrophic Indian Ocean tsunami occurred on December 26, 2004 raised a number of urgent issues regarding tsunamis worldwide. The event pointed out that we have very little knowledge on mega- tsunamis and on their potential impact on human habitat. The international community is starting to define a common strategy of how to deal with these mega-events, and several projects focussed on tsunamis, with emphasis on hazard and risk assessment, have recently started or are going to start soon worldwide both at national and international levels. Properly dealing with tsunami hazard and risk is of great importance also for the Mediterranean countries, that are known to have been attacked by numerous tsunamis in the past, several of which had catastrophic size and impact. Scenarios represent a very useful technique for the definition and evaluation of tsunami hazard and risk for any given region, and a basic step in the frame of tsunami mitigation and preparedness and of sustainable coastal zone development. We present some simple scenarios of earthquake-generated tsunamis in the Mediterranean. Based on earthquake and tsunami catalogues as well as on basic seismotectonics, we identify four different seismogenic areas in the western, central and eastern sectors of the Mediterranean Sea. In each case, we choose a fault system capable of generating an earthquake with magnitude equal or larger than the highest magnitude registered in that region in historical times. We simulate the propagation of each scenario tsunami by means of a shallow-water finite-element numerical code, discuss the basic features of the wave propagation and roughly identify the Mediterranean coastal sectors expected to suffer the heaviest tsunami effects. One important outcome is that all the studied scenario tsunamis are able to produce relevant effects both locally and at trans-Mediterranean distances. Furthermore, the tsunami waves attack the nearest coasts within at most 15 minutes, which

  7. The origin of Phobos grooves from ejecta launched from impact craters on Mars: Tests of the hypothesis

    NASA Astrophysics Data System (ADS)

    Ramsley, Kenneth R.; Head, James W.

    2013-01-01

    The surface of the martian moon Phobos is characterized by parallel and intersecting grooves that bear resemblance to secondary crater chains observed on planetary surfaces. Murray (2011) has hypothesized that the main groove-forming process on Phobos is the intersection of Phobos with ejecta from primary impact events on Mars to produce chains of secondary craters. The hypothesis infers a pattern of parallel jets of ejecta, either fluidized or solidified, that break into equally-spaced fragments and disperse uniformly along-trajectory during the flight from Mars to Phobos. At the moment of impact with Phobos the dispersed fragments emplace secondary craters that are aligned along strike corresponding to the flight pattern of ejecta along trajectory. The aspects of the characteristics of grooves on Phobos cited by this hypothesis that might be explained by secondary ejecta include: their observed linearity, parallelism, planar alignment, pitted nature, change in character along strike, and a "zone of avoidance" where ejecta from Mars is predicted not to impact (Murray, 2011). To test the hypothesis we plot precise Keplerian orbits for ejecta from Mars (elliptical and hyperbolic with periapsis located below the surface of Mars). From these trajectories we: (1) set the fragment dispersion limits of ejecta patterns required to emplace the more typically well-organized parallel grooves observed in returned images from Phobos; (2) plot ranges of the ejecta flight durations from Mars to Phobos and map regions of exposure; (3) utilize the same exposure map to observe trajectory-defined ejecta exposure shadows; (4) observe hemispheric exposure in response to shorter and longer durations of ejecta flight; (5) assess the viability of ejecta emplacing the large family of grooves covering most of the northern hemisphere of Phobos; and (6) plot the arrival of parallel lines of ejecta emplacing chains of craters at oblique incident angles. We also assess the bulk volume of

  8. Engaging Students through Effective Questions

    ERIC Educational Resources Information Center

    Neal, Mary-Anne

    2011-01-01

    In what ways might questioning techniques improve student learning? What kinds of questions enable educators to tap into different parts of the cognitive domain? How can questions engage students when their attention begins to wander? Many questions at the lower levels of Bloom's Taxonomy--particularly knowledge and comprehension--are closed-ended…

  9. Unproven (questionable) cancer therapies.

    PubMed Central

    Brigden, M L

    1995-01-01

    More than half of all cancer patients use some form of alternative treatment during the course of their illness. Alternative therapies are often started early in patients' illness, and their use is frequently not acknowledged to health care professionals. Some alternative therapies are harmful, and their promoters may be fraudulent. Persons who try alternative cancer therapies may not be poorly educated but may ultimately abandon conventional treatment. Recent attention has focused on aspects of questionable therapies that make these treatments attractive to patients and that may be perceived as being deficient in the practice of conventional health care professionals. Physicians with patients with cancer should always make sure that unproven therapies are discussed early in the therapeutic relationship. They should also attempt to be aware of alternative therapies that are in vogue in their particular geographic area. PMID:8533410

  10. Ask an intelligent question...

    SciTech Connect

    Mann, K.

    1995-05-01

    In recent years, as electric utilities have moved toward deregualtion, industry watchers have counceled them to create streamlined competitor intelligence functions or else be outstripped by utilities that do. Gathering competitor intelligence stays focused on answering key questions and showing a cource of action. To that extent, it is part and parcel of good decision-making. In strategic analysis, intelligence focuses on broad-scale comparisons to other electric utilities to determine competitive strengths, weaknesses, opportunities, and threats. This information helps utilities develop business strategies, including a high-level view of what products and services to offer customers. The objective is to ensure that the company doesn`t miss an important issue or trend, so such analysis is ongoing and benefits from a visionary or creative viewpoint.

  11. The origin, evolution, and functional impact of short insertion-deletion variants identified in 179 human genomes.

    PubMed

    Montgomery, Stephen B; Goode, David L; Kvikstad, Erika; Albers, Cornelis A; Zhang, Zhengdong D; Mu, Xinmeng Jasmine; Ananda, Guruprasad; Howie, Bryan; Karczewski, Konrad J; Smith, Kevin S; Anaya, Vanessa; Richardson, Rhea; Davis, Joe; MacArthur, Daniel G; Sidow, Arend; Duret, Laurent; Gerstein, Mark; Makova, Kateryna D; Marchini, Jonathan; McVean, Gil; Lunter, Gerton

    2013-05-01

    Short insertions and deletions (indels) are the second most abundant form of human genetic variation, but our understanding of their origins and functional effects lags behind that of other types of variants. Using population-scale sequencing, we have identified a high-quality set of 1.6 million indels from 179 individuals representing three diverse human populations. We show that rates of indel mutagenesis are highly heterogeneous, with 43%-48% of indels occurring in 4.03% of the genome, whereas in the remaining 96% their prevalence is 16 times lower than SNPs. Polymerase slippage can explain upwards of three-fourths of all indels, with the remainder being mostly simple deletions in complex sequence. However, insertions do occur and are significantly associated with pseudo-palindromic sequence features compatible with the fork stalling and template switching (FoSTeS) mechanism more commonly associated with large structural variations. We introduce a quantitative model of polymerase slippage, which enables us to identify indel-hypermutagenic protein-coding genes, some of which are associated with recurrent mutations leading to disease. Accounting for mutational rate heterogeneity due to sequence context, we find that indels across functional sequence are generally subject to stronger purifying selection than SNPs. We find that indel length modulates selection strength, and that indels affecting multiple functionally constrained nucleotides undergo stronger purifying selection. We further find that indels are enriched in associations with gene expression and find evidence for a contribution of nonsense-mediated decay. Finally, we show that indels can be integrated in existing genome-wide association studies (GWAS); although we do not find direct evidence that potentially causal protein-coding indels are enriched with associations to known disease-associated SNPs, our findings suggest that the causal variant underlying some of these associations may be indels.

  12. The origin, evolution, and functional impact of short insertion-deletion variants identified in 179 human genomes.

    PubMed

    Montgomery, Stephen B; Goode, David L; Kvikstad, Erika; Albers, Cornelis A; Zhang, Zhengdong D; Mu, Xinmeng Jasmine; Ananda, Guruprasad; Howie, Bryan; Karczewski, Konrad J; Smith, Kevin S; Anaya, Vanessa; Richardson, Rhea; Davis, Joe; MacArthur, Daniel G; Sidow, Arend; Duret, Laurent; Gerstein, Mark; Makova, Kateryna D; Marchini, Jonathan; McVean, Gil; Lunter, Gerton

    2013-05-01

    Short insertions and deletions (indels) are the second most abundant form of human genetic variation, but our understanding of their origins and functional effects lags behind that of other types of variants. Using population-scale sequencing, we have identified a high-quality set of 1.6 million indels from 179 individuals representing three diverse human populations. We show that rates of indel mutagenesis are highly heterogeneous, with 43%-48% of indels occurring in 4.03% of the genome, whereas in the remaining 96% their prevalence is 16 times lower than SNPs. Polymerase slippage can explain upwards of three-fourths of all indels, with the remainder being mostly simple deletions in complex sequence. However, insertions do occur and are significantly associated with pseudo-palindromic sequence features compatible with the fork stalling and template switching (FoSTeS) mechanism more commonly associated with large structural variations. We introduce a quantitative model of polymerase slippage, which enables us to identify indel-hypermutagenic protein-coding genes, some of which are associated with recurrent mutations leading to disease. Accounting for mutational rate heterogeneity due to sequence context, we find that indels across functional sequence are generally subject to stronger purifying selection than SNPs. We find that indel length modulates selection strength, and that indels affecting multiple functionally constrained nucleotides undergo stronger purifying selection. We further find that indels are enriched in associations with gene expression and find evidence for a contribution of nonsense-mediated decay. Finally, we show that indels can be integrated in existing genome-wide association studies (GWAS); although we do not find direct evidence that potentially causal protein-coding indels are enriched with associations to known disease-associated SNPs, our findings suggest that the causal variant underlying some of these associations may be indels. PMID

  13. Questions of copyright.

    PubMed

    Anfray, Caroline; Emery, Marie-Pierre; Conway, Katrin; Acquadro, Catherine

    2012-01-31

    The Berne Convention and the national laws on intellectual property fully apply to PRO instruments. The identification of and access to an original PRO instrument is often associated with copyright ownership. This is the copyright holder of the instrument who will control its access (distribution and reproduction), its adaptation or modification, and its translation. Copyright is a means to protect the integrity of an instrument. The ownership of an instrument should be defined in the beginning between all parties involved, and each step of the instrument's life, including distribution, should be anticipated for purpose of copyright.

  14. Systemic Sclerosis: Commonly Asked Questions by Rheumatologists

    PubMed Central

    Young, Amber; Khanna, Dinesh

    2016-01-01

    Systemic sclerosis is a rare autoimmune disorder with significant morbidity and mortality due to multi-organ system involvement. Early diagnosis and screening for organ involvement is critical as earlier treatment appears to improve function and may impact mortality. The purpose of this article is to address some of the commonly asked questions by rheumatologists on systemic sclerosis. PMID:25807095

  15. Common Questions about Sexual Health Education.

    ERIC Educational Resources Information Center

    McKay, Alexander

    2000-01-01

    Provides research-based answers to questions commonly posed by educators, parents, and others about the philosophy, methods, and impact of school sexual health education, discussing such issues as: whether these school programs are needed, what values they teach, whether the programs should teach about sexual orientation and abstinence, and…

  16. MERGER RATES OF DOUBLE NEUTRON STARS AND STELLAR ORIGIN BLACK HOLES: THE IMPACT OF INITIAL CONDITIONS ON BINARY EVOLUTION PREDICTIONS

    SciTech Connect

    Mink, S. E. de; Belczynski, K. E-mail: kbelczyn@astrouw.edu.pl

    2015-11-20

    The initial mass function (IMF), binary fraction, and distributions of binary parameters (mass ratios, separations, and eccentricities) are indispensable inputs for simulations of stellar populations. It is often claimed that these are poorly constrained, significantly affecting evolutionary predictions. Recently, dedicated observing campaigns have provided new constraints on the initial conditions for massive stars. Findings include a larger close binary fraction and a stronger preference for very tight systems. We investigate the impact on the predicted merger rates of neutron stars and black holes. Despite the changes with previous assumptions, we only find an increase of less than a factor of 2 (insignificant compared with evolutionary uncertainties of typically a factor of 10–100). We further show that the uncertainties in the new initial binary properties do not significantly affect (within a factor of 2) our predictions of double compact object merger rates. An exception is the uncertainty in IMF (variations by a factor of 6 up and down). No significant changes in the distributions of final component masses, mass ratios, chirp masses, and delay times are found. We conclude that the predictions are, for practical purposes, robust against uncertainties in the initial conditions concerning binary parameters, with the exception of the IMF. This eliminates an important layer of the many uncertain assumptions affecting the predictions of merger detection rates with the gravitational wave detectors aLIGO/aVirgo.

  17. Merger Rates of Double Neutron Stars and Stellar Origin Black Holes: The Impact of Initial Conditions on Binary Evolution Predictions

    NASA Astrophysics Data System (ADS)

    de Mink, S. E.; Belczynski, K.

    2015-11-01

    The initial mass function (IMF), binary fraction, and distributions of binary parameters (mass ratios, separations, and eccentricities) are indispensable inputs for simulations of stellar populations. It is often claimed that these are poorly constrained, significantly affecting evolutionary predictions. Recently, dedicated observing campaigns have provided new constraints on the initial conditions for massive stars. Findings include a larger close binary fraction and a stronger preference for very tight systems. We investigate the impact on the predicted merger rates of neutron stars and black holes. Despite the changes with previous assumptions, we only find an increase of less than a factor of 2 (insignificant compared with evolutionary uncertainties of typically a factor of 10–100). We further show that the uncertainties in the new initial binary properties do not significantly affect (within a factor of 2) our predictions of double compact object merger rates. An exception is the uncertainty in IMF (variations by a factor of 6 up and down). No significant changes in the distributions of final component masses, mass ratios, chirp masses, and delay times are found. We conclude that the predictions are, for practical purposes, robust against uncertainties in the initial conditions concerning binary parameters, with the exception of the IMF. This eliminates an important layer of the many uncertain assumptions affecting the predictions of merger detection rates with the gravitational wave detectors aLIGO/aVirgo.

  18. On the Origin of Rheumatoid Arthritis: The Impact of Environment and Genes—A Population Based Twin Study

    PubMed Central

    Svendsen, Anders J.; Kyvik, Kirsten O.; Houen, Gunnar; Junker, Peter; Christensen, Kaare; Christiansen, Lene; Nielsen, Christian; Skytthe, Axel; Hjelmborg, Jacob V.

    2013-01-01

    Background Rheumatoid arthritis (RA) is an autoimmune disease with a complex origin. Previous studies have reported heritability estimates on RA at about 60%. Only 16% of the genetic background of the disease has been disclosed so far. The purpose of the present investigation was to provide an optimized estimate on the heritability of RA and to study the recurrence risk in a nationwide Caucasian twin population. Methods and Findings In a mail survey addressed to 56.707 twin individuals, RA was reported by 479 individuals, mean age 52 (range 16–73). Respondents underwent an interview and clinical examination. Ascertainment probability was 80%. RA was confirmed in 162 twin individuals yielding a prevalence at 0.37% (95% CI 0.31–0.43). The mean discordance time was 19 years (range 0–57). The concordance was 9.1% (95% CI 1.9 to 24.3) in MZ, 6.4% (95% CI 2.1 to 14.3) in DZss. The increased relative risk of attracting RA conditioned on having an affected cotwin compared to the background population risk was 24.6 to 35.4 in MZ twins and 17.3 to 31.6 in DZss twins. The correlation coefficients were 0.60 (0.33 to 0.78) in monozygotic (MZ) and 0.55 (0.33 to 0.72) in dizygotic same sexed (DZss) pairs. Twelve percent (95% CI 0–76%) of the phenotypic variance in the liability to RA was due to additive genetic effects, 50% (95% CI 0–72%) to shared environmental effects and 38% (95% CI 17–61%) to non-shared environmental effects. Conclusions This study emphasizes that family factors are important for the development of RA. Although genetic effectors are important, shared and non-shared environmental triggers and/or epigenetic stochastic events seem to be even more significant. However, it should be borne in mind that the genetic and non-genetic components may not be the same across disease subsets. PMID:23468964

  19. Nucleosynthesis: a field with still many open nuclear physics questions

    SciTech Connect

    Goriely, S.

    2010-06-01

    Stellar nucleosynthesis is a vastly interdisciplinary field. There is a large number of different problems invoked calling for a variety of different and complementary research fields. Impressive progress has been made for the last decades in the various fields related to nucleosynthesis, especially in experimental and theoretical nuclear physics, as well as in ground-based or space astronomical observations and astrophysical modellings. In spite of that success, major problems and puzzles remain. The three major nucleosynthesis processes called for to explain the origin of the elements heavier than iron are described and the major pending questions discussed. As far as nuclear physics is concerned, good quality nuclear data is known to be a necessary condition for a reliable modelling of stellar nucleosynthesis. Through some specific examples, the need for further theoretical or experimental developments is also critically discussed in view of their impact on nucleosynthesis predictions.

  20. Early Archean spherule beds of possible impact origin from Barberton, South Africa: A detailed mineralogical and geochemical study

    NASA Astrophysics Data System (ADS)

    Koeberl, Christian; Reimold, Wolf Uwe; Boer, Rudolf H.

    1992-12-01

    The Barberton Greenstone belt is a 3.5- to 3.2-Ga-old formation situated in the Swaziland Supergroup near Barberton, northeast Transvaal, South Africa. The belt includes a lower, predominantly volcanic sequence, and an upper sedimentary sequence (e.g., the Fig Tree Group). Within this upper sedimentary sequence, Lowe and Byerly identified a series of different beds of spherules with diameters of around 0.5-2 mm. Lowe and Byerly and Lowe et al. have interpreted these spherules to be condensates of rock vapor produced by large meteorite impacts in the early Archean. We have collected a series of samples from drill cores from the Mt. Morgan and Princeton sections near Barberton, as well as samples taken from underground exposures in the Sheba and Agnes mines. These samples seem much better preserved than the surface samples described by Lowe and Byerly and Lowe et al. Over a scale of just under 30 cm, several well-defined spherule beds are visible, interspaced with shales and/or layers of banded iron formation. Some spherules have clearly been deposited on top of a sedimentary unit because the shale layer shows indentions from the overlying spherules. Although fresher than the surface samples (e.g., spherule bed S-2), there is abundant evidence for extensive alteration, presumably by hydrothermal processes. In some sections of the cores sulfide mineralization is common. For our mineralogical and petrographical studies we have prepared detailed thin sections of all core and underground samples (as well as some surface samples from the S-2 layer for comparison). For geochemical work, layers with thicknesses in the order of 1-5 mm were separated from selected core and underground samples. The chemical analyses are being performed using neutron activation analysis in order to obtain data for about 35 trace elements in each sample. Major elements are being determined by XRF and plasma spectrometry. To clarify the history of the sulfide mineralization, sulfur isotopic

  1. Early Archean spherule beds of possible impact origin from Barberton, South Africa: A detailed mineralogical and geochemical study

    NASA Technical Reports Server (NTRS)

    Koeberl, Christian; Reimold, Wolf Uwe; Boer, Rudolf H.

    1992-01-01

    The Barberton Greenstone belt is a 3.5- to 3.2-Ga-old formation situated in the Swaziland Supergroup near Barberton, northeast Transvaal, South Africa. The belt includes a lower, predominantly volcanic sequence, and an upper sedimentary sequence (e.g., the Fig Tree Group). Within this upper sedimentary sequence, Lowe and Byerly identified a series of different beds of spherules with diameters of around 0.5-2 mm. Lowe and Byerly and Lowe et al. have interpreted these spherules to be condensates of rock vapor produced by large meteorite impacts in the early Archean. We have collected a series of samples from drill cores from the Mt. Morgan and Princeton sections near Barberton, as well as samples taken from underground exposures in the Sheba and Agnes mines. These samples seem much better preserved than the surface samples described by Lowe and Byerly and Lowe et al. Over a scale of just under 30 cm, several well-defined spherule beds are visible, interspaced with shales and/or layers of banded iron formation. Some spherules have clearly been deposited on top of a sedimentary unit because the shale layer shows indentions from the overlying spherules. Although fresher than the surface samples (e.g., spherule bed S-2), there is abundant evidence for extensive alteration, presumably by hydrothermal processes. In some sections of the cores sulfide mineralization is common. For our mineralogical and petrographical studies we have prepared detailed thin sections of all core and underground samples (as well as some surface samples from the S-2 layer for comparison). For geochemical work, layers with thicknesses in the order of 1-5 mm were separated from selected core and underground samples. The chemical analyses are being performed using neutron activation analysis in order to obtain data for about 35 trace elements in each sample. Major elements are being determined by XRF and plasma spectrometry. To clarify the history of the sulfide mineralization, sulfur isotopic

  2. Ni/S/Cl systematics and the origin of impact-melt glasses in Martian meteorite Elephant Moraine 79001

    NASA Astrophysics Data System (ADS)

    Schrader, Christian M.; Cohen, Barbara A.; Donovan, John J.; Vicenzi, Edward P.

    2016-04-01

    Martian meteorite Elephant Moraine A79001 (EET 79001) has received considerable attention for the unusual composition of its shock melt glass, particularly its enrichment in sulfur relative to the host shergottite. It has been hypothesized that Martian regolith was incorporated into the melt or, conversely, that the S-enrichment stems from preferential melting of sulfide minerals in the host rock during shock. We present results from an electron microprobe study of EET 79001 including robust measurements of major and trace elements in the shock melt glass (S, Cl, Ni, Co, V, and Sc) and minerals in the host rock (Ni, Co, and V). We find that both S and major element abundances can be reconciled with previous hypotheses of regolith incorporation and/or excess sulfide melt. However, trace element characteristics of the shock melt glass, particularly Ni and Cl abundances relative to S, cannot be explained either by the incorporation of regolith or sulfide minerals. We therefore propose an alternative hypothesis whereby, prior to shock melting, portions of EET 79001 experienced acid-sulfate leaching of the mesostasis, possibly groundmass feldspar, and olivine, producing Al-sulfates that were later incorporated into the shock melt, which then quenched to glass. Such activity in the Martian near-surface is supported by observations from the Mars Exploration Rovers and laboratory experiments. Our preimpact alteration model, accompanied by the preferential survival of olivine and excess melting of feldspar during impact, explains the measured trace element abundances better than either the regolith incorporation or excess sulfide melting hypothesis does.

  3. Children's questions: a mechanism for cognitive development.

    PubMed

    Chouinard, Michael M

    2007-01-01

    methodology allowed detailed, veridical analysis of every question asked by the children during their recording sessions. Results indicate that children ask many information-seeking questions and get informative answers. When they do not get an informative response, they keep asking; attention is not enough. Results also indicate that the content of children's questions parallel their conceptual advances, and shift within an exchange and over the course of development to reflect the learning process. So, these data suggest that the components of the IRM are in place and are used by children from very early in development, and the information they seek changes with time. Study 2 asked whether preverbal children who are not yet asking linguistic questions can recruit information via gestures, expressions, and vocalizations, in addition to further investigating the linguistic questions of older children. This study analyzed questions from a cross-sectional diary study, kept by 68 parents of their children's questions (aged 1;0-5;0). Also, this methodology allowed for data collection over a large number of children, a large range of situational contexts, and allows for the collection of low frequency, high-salience events. Results from Study 2 suggest that all of the components of the IRM are in place, and extends these findings down to younger, preverbal children who recruit information using gesture and vocalizations. Study 3 investigated the questions asked in one specific domain, biological knowledge, and examined the impact that different stimulus types have on children's questions. This study gathered data from 112 parent/child dyads (children aged 2, 3, and 4 years) walking through one of three zoos (one with real animals, one with drawings of animals, and one with three-dimensional replicas of animals), looking at the animals together. Results from this study also suggest that all of the components of the IRM are in place from the earliest age, further supporting the

  4. Children's questions: a mechanism for cognitive development.

    PubMed

    Chouinard, Michael M

    2007-01-01

    methodology allowed detailed, veridical analysis of every question asked by the children during their recording sessions. Results indicate that children ask many information-seeking questions and get informative answers. When they do not get an informative response, they keep asking; attention is not enough. Results also indicate that the content of children's questions parallel their conceptual advances, and shift within an exchange and over the course of development to reflect the learning process. So, these data suggest that the components of the IRM are in place and are used by children from very early in development, and the information they seek changes with time. Study 2 asked whether preverbal children who are not yet asking linguistic questions can recruit information via gestures, expressions, and vocalizations, in addition to further investigating the linguistic questions of older children. This study analyzed questions from a cross-sectional diary study, kept by 68 parents of their children's questions (aged 1;0-5;0). Also, this methodology allowed for data collection over a large number of children, a large range of situational contexts, and allows for the collection of low frequency, high-salience events. Results from Study 2 suggest that all of the components of the IRM are in place, and extends these findings down to younger, preverbal children who recruit information using gesture and vocalizations. Study 3 investigated the questions asked in one specific domain, biological knowledge, and examined the impact that different stimulus types have on children's questions. This study gathered data from 112 parent/child dyads (children aged 2, 3, and 4 years) walking through one of three zoos (one with real animals, one with drawings of animals, and one with three-dimensional replicas of animals), looking at the animals together. Results from this study also suggest that all of the components of the IRM are in place from the earliest age, further supporting the

  5. Questioning cochlear amplification

    NASA Astrophysics Data System (ADS)

    van der Heijden, Marcel; Versteegh, Corstiaen P. C.

    2015-12-01

    Thirty years ago it was hypothesized that motile processes inject mechanical energy into cochlear traveling waves. This mechanical amplification, alternatively described as negative damping, is invoked to explain both the sensitivity and the nonlinear compression of cochlear responses. There is a recent trend to present cochlear amplification as an established fact, even though the evidence is at most circumstantial and several thorny problems have remained unresolved. We analyze several of these issues, and present new basilar membrane recordings that allowed us to quantify cochlear energy flow. Specifically, we address the following questions: (1) Does auditory sensitivity require narrowband amplification? (2) Has the "RC problem" (lowpass filtering of outer hair cell receptor potential) been resolved? (3) Can OHC motility improve auditory sensitivity? (4) Is there a net power gain between neighboring locations on the basilar membrane? The analyses indicate that mechanical amplification in the cochlea is neither necessary nor useful, and that realizing it by known forms of motility would reduce sensitivity rather than enhance it. Finally, our experimental data show that the peaking of the traveling wave is realized by focusing the acoustic energy rather than amplifying it. (Abbreviations. BM: basilar membrane; CF: characteristic frequency; IHC: inner hair cell; ME: middle ear; MT; mechanotransducer; OHC: outer hair cell; SPL: sound pressure level.)

  6. Cosmic questions: an introduction.

    PubMed

    Primack, J R; Abrams, N E

    2001-12-01

    This introductory talk at the Cosmic Questions conference sponsored by the AAAS summarizes some earlier pictures of the universe and some pictures based on modern physics and cosmology. The uroboros (snake swallowing its tail) is an example of a traditional picture. The Biblical flat-earth picture was very different from the Greek spherical earth-centered picture, which was the standard view until the end of the Middle Ages. Many people incorrectly assume that the Newtonian picture of stars scattered through otherwise empty space is still the prevailing view. Seeing Earth from space shows the power of a new picture. The Hubble Space Telescope can see all the bright galaxies, all the way to the cosmic Dark Ages. We are at the center of cosmic spheres of time: looking outward is looking backward in time. All the matter and energy in the universe can be represented as a cosmic density pyramid. The laws of physics only allow the material objects in the universe to occupy a wedge-shaped region on a diagram of mass versus size. All sizes--from the smallest size scale, the Planck scale, to the entire visible universe--can be represented on the Cosmic Uroboros. There are interesting connections across this diagram, and the human scale lies in the middle. PMID:11797741

  7. Cosmic questions: an introduction.

    PubMed

    Primack, J R; Abrams, N E

    2001-12-01

    This introductory talk at the Cosmic Questions conference sponsored by the AAAS summarizes some earlier pictures of the universe and some pictures based on modern physics and cosmology. The uroboros (snake swallowing its tail) is an example of a traditional picture. The Biblical flat-earth picture was very different from the Greek spherical earth-centered picture, which was the standard view until the end of the Middle Ages. Many people incorrectly assume that the Newtonian picture of stars scattered through otherwise empty space is still the prevailing view. Seeing Earth from space shows the power of a new picture. The Hubble Space Telescope can see all the bright galaxies, all the way to the cosmic Dark Ages. We are at the center of cosmic spheres of time: looking outward is looking backward in time. All the matter and energy in the universe can be represented as a cosmic density pyramid. The laws of physics only allow the material objects in the universe to occupy a wedge-shaped region on a diagram of mass versus size. All sizes--from the smallest size scale, the Planck scale, to the entire visible universe--can be represented on the Cosmic Uroboros. There are interesting connections across this diagram, and the human scale lies in the middle.

  8. Promoting Student Learning Through Questioning: A Study of Classroom Questions.

    ERIC Educational Resources Information Center

    Edwards, Sandra; Bowman, Mary Ann

    1996-01-01

    A study in a graduate-level occupational therapy class found that questions asked by teachers and the instructional format in which they were asked influenced the frequency and level of student questioning. Subjects were 5 undergraduate and 15 graduate students. It was concluded that improved classroom questioning strategies may contribute to…

  9. The Martian atmosphere: some unanswered questions.

    PubMed

    Owen, T

    1979-12-01

    The study of the Martian atmosphere and its significance for the possible origin of life on Mars is still very incomplete. Further investigations are needed to define the total volatile inventory, the early history of the atmosphere, and the relationship of the atmosphere to the question of indigenous life. In addition, studies of Venus, comets, and the Jupiter system will add significantly to our abilities to understand the early history of Mars.

  10. Questions and Answers about Psychosis

    MedlinePlus

    ... treatment options? Questions & Answers about the NIMH RAISE Project What is RAISE? Why is RAISE important? What ... more information Questions & Answers about the NIMH RAISE Project Q: What is RAISE? A: In 2008, the ...

  11. Antibiotic Resistance Questions and Answers

    MedlinePlus

    ... on the Farm Get Smart About Antibiotics Week Antibiotic Resistance Questions and Answers Language: English Español (Spanish) Recommend ... Many ear infections Top of Page Questions about Antibiotic Resistance Examples of How Antibiotic Resistance Spreads Click for ...

  12. Questions for Music Education Research

    ERIC Educational Resources Information Center

    Jorgensen, Estelle R.

    2008-01-01

    In addressing the question-set "What questions do music education researchers need to address?", an illustrative list of juxtaposed descriptive and normative questions is sketched as follows: What are and should be the dimensions of music education? What are and should be the institutional agencies of music education? What are and should be the…

  13. Improving the Questions Students Ask

    ERIC Educational Resources Information Center

    Donohue-Smith, Maureen

    2006-01-01

    Teachers often tell their classes that "there is no such thing as a stupid question." But this is not completely honest. Questions aren't asked in a vacuum; their intelligence or stupidity depends on a variety of contextual variables. The ideal question is the right one, posed to the right source in the right way at the right time for the right…

  14. The Questions of Liberal Education

    ERIC Educational Resources Information Center

    Arcilla, Rene V.

    2007-01-01

    There is a certain kind of liberal educator who bases his or her practice on a particular attitude toward the "Big Questions." The questions of fundamental literacy in K-12 education, or of expertise in vocational and professional education, may be just as important, but they are seen as quite different in kind. Indeed, the questions of liberal…

  15. Improving your IQ -- Intelligent Questioning.

    ERIC Educational Resources Information Center

    Kassner, Kirk

    1998-01-01

    Stresses the importance for teachers to analyze their Intelligent Questioning (IQ) and Responding to Answers (RSA) scores. Provides three methods for measuring IQ and RSA: Flowchart for Asking Effective Questions, Questioning Observation form, and Flanders Technique of Interaction Analysis. Contends that by improving these teaching skills,…

  16. Does Anyone Have Any Questions?

    ERIC Educational Resources Information Center

    Finkelstein, Judith M.; Ritter, Virginia F.

    The purpose of this study was to determine if answering a child's question with a question produces further analytical questioning by the child. A sample of 80 children in nursery-kindergarten, first, second and third grades (ages ranging from 4-9 years) were divided into two groups. An abstract painting by Kandinsky was shown individually to each…

  17. Postreading Questioning and Middle School Students' Understanding of Literature

    ERIC Educational Resources Information Center

    Liang, Lauren Aimonette; Watkins, Naomi M.; Graves, Michael F.; Hosp, John

    2010-01-01

    The study examined the effectiveness of a "story map," a questioning technique (Beck & McKeown, 1981) for improving students' understanding of literature. Though the story map idea was widely adopted as a student-initiated strategy, the original story map--a teacher-generated, postreading questioning framework--was never empirically tested. This…

  18. The interplanetary superhighway and the Origins Program

    NASA Technical Reports Server (NTRS)

    Lo, M. W.

    2002-01-01

    The origin of the universe and of life itself have been central to human inquiries since the dawn of consciousness. To develop and use the technologies to answer these timeless and profound questions is the mission of NASA's Origins Program.

  19. The Enigma of the Origin of Round, Deep, Rimed Lakes in the Russian Heartland-Was Lake Smerdyachie Formed During the Impact of an Extraterrestrial Body?

    NASA Astrophysics Data System (ADS)

    Abbott, D. H.; Gusiakov, V. K.; Kiselev, A.; Amelin, I. I.; Breger, D. L.; McCafferty, P.

    2014-12-01

    The heartland of Russia has many enigmatic deep lakes. Shallow lakes have a more obvious origin, perhaps as kettle lakes, oxbow lakes or subsidence features. Deep lakes, particularly round lakes with partial or complete rims are more problematic. Traditionally, round or nearly round lakes with rims are candidates for Holocene age impact structures. The problem is that there are too many such lakes in the Russian heartland- a minimum of 15 deep, round lakes with diameters between 0.2 and 3 km. Even with a possibly increased impact rate during the Holocene, these deep lakes would represent the entire budget of Holocene impacts concentrated in one small region of the Earth. We examine here Lake Smerdyachie, a previously proposed impact lake. Smerdyachie is perfectly round with a raised rim. It has a diameter of about 350 meters and a maximum water depth of over 30 m. The basement at Smerdyachie is at~40 meters depth. It consists of Carboniferous age carbonate rock with fossils of brachiopods, crinoids and gastropods. The overlying material consists of unconsolidated, sand and silt-sized, quartz-rich sediments. We found clasts of brachiopod, crinoid and gastropod-bearing Carboniferous carbonate rock up to 32 cm in diameter on the SE rim of Smerdyachie. These clasts are present over about 1/3 of the total circumference of the lake. We also made panned concentrates of the sediment on the rim. To the NW, the concentrated sediment has a negative magnetic susceptibility (-0.07 to -0.03 cgs units), consistent with a higher concentration of pulverized limestone. To the SE, the sediment has a positive magnetic susceptibility (0.06 to 0.35 cgs units). The areas of positive magnetic susceptibility lie on the SE two-thirds of the rim of the lake. The highest susceptibility value is from the sample taken closest to the lake shoreline on the SE rim. This spatial distribution of susceptibility could mean that there is a higher concentration of iron rich material on the SE side of

  20. Questioning Our Questions: Assessing Question Asking Practices to Evaluate a yPAR Program

    ERIC Educational Resources Information Center

    Grace, Sarah; Langhout, Regina Day

    2014-01-01

    The purpose of this research was to examine question asking practices in a youth participatory action research (yPAR) after school program housed at an elementary school. The research question was: In which ways did the adult question asking practices in a yPAR setting challenge and/or reproduce conventional models of power in educational…

  1. Origin of strong lunar magnetic anomalies: Further mapping and examinations of LROC imagery in regions antipodal to young large impact basins

    NASA Astrophysics Data System (ADS)

    Hood, Lon L.; Richmond, Nicola C.; Spudis, Paul D.

    2013-06-01

    The existence of magnetization signatures and landform modification antipodal to young lunar impact basins is investigated further by (a) producing more detailed regional crustal magnetic field maps at low altitudes using Lunar Prospector magnetometer data; and (b) examining Lunar Reconnaissance Orbiter Wide Angle Camera imagery. Of the eight youngest lunar basins, five are found to have concentrations of relatively strong magnetic anomalies centered within 10° of their antipodes. This includes the polar Schrödinger basin, which is one of the three youngest basins and has not previously been investigated in this context. Unusual terrain is also extensively present near the antipodes of the two largest basins (Orientale and Imbrium) while less pronounced manifestations of this terrain may be present near the antipodes of Serenitatis and Schrödinger. The area near the Imbrium antipode is characterized by enhanced surface thorium abundances, which may be a consequence of antipodal deposition of ejecta from Imbrium. The remaining three basins either have antipodal regions that have been heavily modified by later events (Hertzsprung and Bailly) or are not clearly recognized to be a true basin (Sikorsky-Rittenhouse). The most probable source of the Descartes anomaly, which is the strongest isolated magnetic anomaly, is the hilly and furrowed Descartes terrain near the Apollo 16 landing site, which has been inferred to consist of basin ejecta, probably from Imbrium according to one recent sample study. A model for the origin of both the modified landforms and the magnetization signatures near lunar basin antipodes involving shock effects of converging ejecta impacts is discussed.

  2. DNA replication origins.

    PubMed

    Leonard, Alan C; Méchali, Marcel

    2013-10-01

    The onset of genomic DNA synthesis requires precise interactions of specialized initiator proteins with DNA at sites where the replication machinery can be loaded. These sites, defined as replication origins, are found at a few unique locations in all of the prokaryotic chromosomes examined so far. However, replication origins are dispersed among tens of thousands of loci in metazoan chromosomes, thereby raising questions regarding the role of specific nucleotide sequences and chromatin environment in origin selection and the mechanisms used by initiators to recognize replication origins. Close examination of bacterial and archaeal replication origins reveals an array of DNA sequence motifs that position individual initiator protein molecules and promote initiator oligomerization on origin DNA. Conversely, the need for specific recognition sequences in eukaryotic replication origins is relaxed. In fact, the primary rule for origin selection appears to be flexibility, a feature that is modulated either by structural elements or by epigenetic mechanisms at least partly linked to the organization of the genome for gene expression.

  3. Eight questions about invasions and ecosystem functioning.

    PubMed

    Strayer, David L

    2012-10-01

    I pose eight questions central to understanding how biological invasions affect ecosystems, assess progress towards answering those questions and suggest ways in which progress might be made. The questions concern the frequency with which invasions affect ecosystems; the circumstances under which ecosystem change is most likely; the functions that are most often affected by invaders; the relationships between changes to ecosystems, communities, and populations; the long-term responses of ecosystems to invasions; interactions between biological invasions and other anthropogenic activities and the difficulty of managing undesirable impacts of non-native species. Some questions have been answered satisfactorily, others require more data and thought, and others might benefit from being reformulated or abandoned. Actions that might speed progress include careful development of trait-based approaches; strategic collection and publication of new data, including more frequent publication of negative results; replacement of expert opinion with hard data where needed; careful consideration of whether questions really need to be answered, especially in cases where answers are being provided for managers and policy-makers; explicit attention to and testing of the domains of theories; integrating invasions better into an ecosystem context; and remembering that our predictive ability is limited and will remain so for the foreseeable future.

  4. Origin and Health Impacts of Emissions of Toxic By-Products and Fine Particles from Combustion and Thermal Treatment of Hazardous Wastes and Materials

    PubMed Central

    Cormier, Stephania A.; Lomnicki, Slawo; Backes, Wayne; Dellinger, Barry

    2006-01-01

    High-temperature, controlled incineration and thermal treatment of contaminated soils, sediments, and wastes at Superfund sites are often preferred methods of remediation of contaminated sites under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 and related legislation. Although these methods may be executed safely, formation of toxic combustion or reaction by-products is still a cause of concern. Emissions of polycyclic aromatic hydrocarbons (PAHs); chlorinated hydrocarbons (CHCs), including polychlorinated dibenzo-p-dioxins and dibenzofurans; and toxic metals (e.g., chromium VI) have historically been the focus of combustion and health effects research. However, fine particulate matter (PM) and ultrafine PM, which have been documented to be related to cardiovascular disease, pulmonary disease, and cancer, have more recently become the focus of research. Fine PM and ultrafine PM are effective delivery agents for PAHs, CHCs, and toxic metals. In addition, it has recently been realized that brominated hydrocarbons (including brominated/chlorinated dioxins), redox-active metals, and redox-active persistent free radicals are also associated with PM emissions from combustion and thermal processes. In this article, we discuss the origin of each of these classes of pollutants, the nature of their association with combustion-generated PM, and the mechanisms of their known and potential health impacts. PMID:16759977

  5. Cloning: questions answered and unsolved.

    PubMed

    Latham, Keith E

    2004-02-01

    Cloning by the transfer of adult somatic cell nuclei to oocytes has produced viable offspring in a variety of mammalian species. The technology is still in its initial stages of development. Studies to date have answered several basic questions related to such issues as genome potency, life expectancy of clones, mitochondrial fates, and feasibility of inter-species nuclear transfer. They have also raised new questions related to the control of nuclear reprogramming and function. These questions are reviewed here.

  6. Student Moderators in Asynchronous Online Discussion: A Question of Questions

    ERIC Educational Resources Information Center

    Zingaro, Daniel

    2012-01-01

    Much current research exalts the benefits of having students facilitate weekly discussions in asynchronous online courses. This study seeks to add to what is known about student moderation through an analysis of the types of questions students use to spur each discussion. Prior experimental work has demonstrated that the types of questions posed…

  7. Classroom Questioning Techniques: The T.V. Taxonomy of Questions.

    ERIC Educational Resources Information Center

    Kahn, Michael

    The T.V. Taxonomy of Questions was developed for use by teachers who wish to stimulate their students' critical thinking skills, but who find the terminology of existing skill taxonomies both confusing and elusive. This taxonomy consists of six levels of questions. Each level is given the name of a television program reflecting how the student…

  8. Reference Readiness for AV Questions.

    ERIC Educational Resources Information Center

    Drolet, Leon L., Jr.

    1981-01-01

    Reviews 50 reference tools which librarians can use to answer almost any audiovisual question including queries on trivia, equipment selection, biographical information, and motion picture ratings. (LLS)

  9. Tektites and their origin

    NASA Technical Reports Server (NTRS)

    Okeefe, J. A.

    1976-01-01

    Questions concerning the tektite distribution are examined, taking into account the Australasian strewn field, the Ivory Coast strewn field, the Moldavite strewn field, the North American strewn field, the Libyan desert glass, the Aouelloul crater glass, and amerikanites. Attention is given to the shapes of tektites, the internal structure of tektites, the physical properties of tektite glass, the chemical composition of tektites, isotopes, fission tracks, cosmic ray tracks, and arguments in favor and against the terrestrial origin of tektites. It is concluded that tektites cannot be terrestrial in origin. They are probably volcanic ejects, of geologically recent epochs, from one or a number of lunar volcanoes.

  10. Using Seen Examination Questions in Economics: An Evaluation

    ERIC Educational Resources Information Center

    Reimann, Nicola; Robson, Martin

    2013-01-01

    This paper presents a detailed quantitative analysis of the use of seen questions within examinations in Economics option modules at one UK university. 4622 marks for seen and unseen questions awarded over a period of three years were analysed; the impact of personal characteristics was analysed using a sub-sample. It was found that the number of…

  11. Update on Medical Practices that should be questioned in 2015

    PubMed Central

    Morgan, Daniel J.; Dhruva, Sanket S.; Wright, Scott M.; Korenstein, Deborah

    2016-01-01

    Importance Overuse of medical care, consisting primarily of overdiagnosis and overtreatment, is a common clinical problem. Objective To identify and highlight articles published in 2014 that are most likely to impact overuse, organized into the categories of overdiagnosis, overtreatment, and methods to avoid overuse. These manuscripts were reviewed and interpreted for their importance to clinical medicine. Evidence Review A structured review of English-language articles on PubMed published in 2014 and review of tables of contents of relevant journals to identify potential articles that related to medical overuse in adults. Findings We reviewed 910 articles, of which 440 addressed overuse. Of these, 104 were deemed most relevant based on the presentation of original data, quality of methodology, magnitude of clinical impact, and the number of patients potentially affected. The 10 most influential articles were selected by author consensus using the same criteria. Findings included lack of benefit for screening pelvic examinations (positive predictive value <5%), carotid artery and thyroid ultrasounds. Harms of cancer screening included unnecessary surgery and complications. Head CT scans were an overused diagnostic test (4% with clinically significant findings) and overtreatment included acetaminophen for low back pain, prolonged opioid use after surgery (3% of patients on >90 days), perioperative aspirin, medications to increase HDL, and stenting for renal artery stenosis. Conclusions and Relevance Many common medical practices should be reconsidered. It is hoped that our review promotes reflection on these 10 articles and lead to questioning other non-evidence based practices. PMID:26551354

  12. Asking Research Questions: Theoretical Presuppositions

    ERIC Educational Resources Information Center

    Tenenberg, Josh

    2014-01-01

    Asking significant research questions is a crucial aspect of building a research foundation in computer science (CS) education. In this article, I argue that the questions that we ask are shaped by internalized theoretical presuppositions about how the social and behavioral worlds operate. And although such presuppositions are essential in making…

  13. Test Pool Questions, Area III.

    ERIC Educational Resources Information Center

    Sloan, Jamee Reid

    This manual contains multiple choice questions to be used in testing students on nurse training objectives. Each test includes several questions covering each concept. The concepts in section A, medical surgical nursing, are diseases of the following systems: musculoskeletal; central nervous; cardiovascular; gastrointestinal; urinary and male…

  14. Answering Your Questions about AIDS.

    ERIC Educational Resources Information Center

    Kalichman, Seth C.

    This book focuses on AIDS education and answers 350 commonly asked questions about Human Immunodeficiency Virus (HIV) and Acquired Immune Deficiency Syndrome (AIDS) taken from questions addressed to two major urban AIDS hotlines (Milwaukee, Wisconsin, and Houston, Texas). Chapter 1, "HIV - The Virus That Causes AIDS," discusses: the HIV virus; the…

  15. Impact and safety of endoscopic ultrasound guided fine needle aspiration on patients with cirrhosis and pyrexia of unknown origin in India

    PubMed Central

    Choudhary, Narendra; Bansal, Rinkesh Kumar; Puri, Rajesh; Singh, Rajiv Ranjan; Nasa, Mukesh; Shah, Vinit; Sarin, Haimanti; Guleria, Mridula; Saigal, Sanjiv; Saraf, Neeraj; Sud, Randhir; Soin, Arvinder S.

    2016-01-01

    Background and aims: Etiologic diagnosis of pyrexia of unknown origin is important in patients with cirrhosis for optimal management and to prevent flare up of infectious disease after liver transplantation. However, there is very limited literature available on this subject. The present study aimed to examine the safety and impact of endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) in patients with cirrhosis. Methods: The study was conducted between January 2014 and January 2016 at a tertiary care center. A total of 50 (47 lymph nodes, 3 adrenal) EUS guided FNAs were performed in 46 patients. Data are presented as median (25 – 75 IQR). Results: The study included 46 patients (40 males) whose mean age was 47.9 ± 11.1 (SD) years; mean Child-Turcotte-Pugh (CTP) score and mean MELD (Model for End-Stage Liver Disease) score were 10 (8 – 11) and 18 (12 – 20), respectively. The Child Pugh class was A in 4, B in 14, and C in 28 (including three patients with adrenal FNAs). Indications for FNA were pyrexia of unknown origin and lymphadenopathy on CT imaging. The cytopathological diagnoses were metastatic disease in 1 (adrenal), granulomatous change in 10 (6 positive with acid fast bacilli stain), histoplasmosis in three (two adrenals, one lymph node), 32 lymph nodes were reactive and four lymph node FNAs showed inadequate cellularity. The pathologic nodes had significantly lower long-to-short axis ratio [1.25 (1.09 – 1.28) versus 1.46 (1.22 – 1.87), P = 0.020]; a higher proportion of hypoechoic echotexture (5 versus 3, P = 0.017), and sharply defined borders (4 versus 2, P = 0.029). Complications included mild hepatic encephalopathy related to sedation in two patients with Child’s C status. Conclusion: EUS guided FNA is safe in patients with cirrhosis and modified the management in 14/46 (30.4 %) patients.

  16. Impact and safety of endoscopic ultrasound guided fine needle aspiration on patients with cirrhosis and pyrexia of unknown origin in India

    PubMed Central

    Choudhary, Narendra; Bansal, Rinkesh Kumar; Puri, Rajesh; Singh, Rajiv Ranjan; Nasa, Mukesh; Shah, Vinit; Sarin, Haimanti; Guleria, Mridula; Saigal, Sanjiv; Saraf, Neeraj; Sud, Randhir; Soin, Arvinder S.

    2016-01-01

    Background and aims: Etiologic diagnosis of pyrexia of unknown origin is important in patients with cirrhosis for optimal management and to prevent flare up of infectious disease after liver transplantation. However, there is very limited literature available on this subject. The present study aimed to examine the safety and impact of endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) in patients with cirrhosis. Methods: The study was conducted between January 2014 and January 2016 at a tertiary care center. A total of 50 (47 lymph nodes, 3 adrenal) EUS guided FNAs were performed in 46 patients. Data are presented as median (25 – 75 IQR). Results: The study included 46 patients (40 males) whose mean age was 47.9 ± 11.1 (SD) years; mean Child-Turcotte-Pugh (CTP) score and mean MELD (Model for End-Stage Liver Disease) score were 10 (8 – 11) and 18 (12 – 20), respectively. The Child Pugh class was A in 4, B in 14, and C in 28 (including three patients with adrenal FNAs). Indications for FNA were pyrexia of unknown origin and lymphadenopathy on CT imaging. The cytopathological diagnoses were metastatic disease in 1 (adrenal), granulomatous change in 10 (6 positive with acid fast bacilli stain), histoplasmosis in three (two adrenals, one lymph node), 32 lymph nodes were reactive and four lymph node FNAs showed inadequate cellularity. The pathologic nodes had significantly lower long-to-short axis ratio [1.25 (1.09 – 1.28) versus 1.46 (1.22 – 1.87), P = 0.020]; a higher proportion of hypoechoic echotexture (5 versus 3, P = 0.017), and sharply defined borders (4 versus 2, P = 0.029). Complications included mild hepatic encephalopathy related to sedation in two patients with Child’s C status. Conclusion: EUS guided FNA is safe in patients with cirrhosis and modified the management in 14/46 (30.4 %) patients. PMID:27652300

  17. The Value Question in Metaphysics.

    PubMed

    Kahane, Guy

    2012-07-01

    Much seems to be at stake in metaphysical questions about, for example, God, free will or morality. One thing that could be at stake is the value of the universe we inhabit-how good or bad it is. We can think of competing philosophical positions as describing possibilities, ways the world might turn out to be, and to which value can be assigned. When, for example, people hope that God exists, or fear that we do not possess free will, they express attitudes towards these possibilities, attitudes that presuppose answers to questions about their comparative value. My aim in this paper is to distinguish these evaluative questions from related questions with which they can be confused, to identify structural constraints on their proper pursuit, and to address objections to their very coherence. Answers to such evaluative questions offer one measure of the importance of philosophical disputes.

  18. The Value Question in Metaphysics

    PubMed Central

    Kahane, Guy

    2012-01-01

    Much seems to be at stake in metaphysical questions about, for example, God, free will or morality. One thing that could be at stake is the value of the universe we inhabit—how good or bad it is. We can think of competing philosophical positions as describing possibilities, ways the world might turn out to be, and to which value can be assigned. When, for example, people hope that God exists, or fear that we do not possess free will, they express attitudes towards these possibilities, attitudes that presuppose answers to questions about their comparative value. My aim in this paper is to distinguish these evaluative questions from related questions with which they can be confused, to identify structural constraints on their proper pursuit, and to address objections to their very coherence. Answers to such evaluative questions offer one measure of the importance of philosophical disputes. PMID:23024399

  19. Original Misunderstanding

    ERIC Educational Resources Information Center

    Holtzman, Alexander

    2009-01-01

    Humorist Josh Billings quipped, "About the most originality that any writer can hope to achieve honestly is to steal with good judgment." Billings was harsh in his view of originality, but his critique reveals a tension faced by students every time they write a history paper. Research is the essence of any history paper. Especially in high school,…

  20. Do clinicians use more question marks?

    PubMed Central

    Otte, Willem M; van’t Klooster, Maryse A; van Diessen, Eric; Leijten, Frans SS; Sander, Josemir W

    2015-01-01

    Objective To quantify the use of question marks in titles of published studies. Design and setting Literature review. Participants All Pubmed publications between 1 January 2013 and 31 December 2013 with an available abstract. Papers were classified as being clinical when the search terms clin*, med* or patient* were found anywhere in the paper’s title, abstract or the journal’s name. Other papers were considered controls. As a verification, clinical journals were compared to non-clinical journals in two different approaches. Also, 50 highest impact journals were explored for publisher group dependent differences. Main outcome measure Total number of question marks in titles. Results A total of 368,362 papers were classified as clinical and 596,889 as controls. Clinical papers had question marks in 3.9% (95% confidence interval 3.8–4.0%) of titles and other papers in 2.3% (confidence interval 2.3–2.3%; p < 0.001). These findings could be verified for clinical journals compared to non-clinical journals. Different percentages between four publisher groups were found (p < 0.01). Conclusion We found more question marks in titles of clinical papers than in other papers. This could suggest that clinicians often have a question-driven approach to research and scientists in more fundamental research a hypothesis-driven approach. An alternative explanation is that clinicians like catchy titles. Publishing groups might have pro- and anti-question mark policies. PMID:26085937

  1. A Set of Questions, A Question of Sets.

    ERIC Educational Resources Information Center

    Mathematics in School, 1985

    1985-01-01

    Two versions of a page of exercises using set ideas are presented, one in plain language and one in technical language. Some questions and answers about the appropriateness of set terminology and symbols are then given. (MNS)

  2. Measuring injury risk factors: question reliability in a statewide sample

    PubMed Central

    Koziol-McLain, J.; Brand, D.; Morgan, D.; Leff, M.; Lowenstein, S.

    2000-01-01

    Background—Recently (1996–98), Colorado added 15 questions pertaining to injury related risks and behaviors to the behavioral risk factor surveillance system (BRFSS). Questions addressed bicycle helmet use, traffic crashes, exposure to violence, suicidal behavior, and gun storage. Objective—To measure the test-retest reliability of these injury related questions. Methods—Of 330 BRFSS participants, 229 (69%) were called a second time and reasked nine selected injury questions. Retests were completed 7–28 days after the original interview. Results—Test-retest agreement was very high (κ >0.80) for bicycle helmet use, domestic police visits, and gun ownership. All other injury risk questions had substantial agreement (κ >0.60). Conclusions—The injury related questions added to the Colorado BRFSS have high test-retest reliability. PMID:10875674

  3. Explaining errors in children's questions.

    PubMed

    Rowland, Caroline F

    2007-07-01

    The ability to explain the occurrence of errors in children's speech is an essential component of successful theories of language acquisition. The present study tested some generativist and constructivist predictions about error on the questions produced by ten English-learning children between 2 and 5 years of age. The analyses demonstrated that, as predicted by some generativist theories [e.g. Santelmann, L., Berk, S., Austin, J., Somashekar, S. & Lust. B. (2002). Continuity and development in the acquisition of inversion in yes/no questions: dissociating movement and inflection, Journal of Child Language, 29, 813-842], questions with auxiliary DO attracted higher error rates than those with modal auxiliaries. However, in wh-questions, questions with modals and DO attracted equally high error rates, and these findings could not be explained in terms of problems forming questions with why or negated auxiliaries. It was concluded that the data might be better explained in terms of a constructivist account that suggests that entrenched item-based constructions may be protected from error in children's speech, and that errors occur when children resort to other operations to produce questions [e.g. Dabrowska, E. (2000). From formula to schema: the acquisition of English questions. Cognitive Liguistics, 11, 83-102; Rowland, C. F. & Pine, J. M. (2000). Subject-auxiliary inversion errors and wh-question acquisition: What children do know? Journal of Child Language, 27, 157-181; Tomasello, M. (2003). Constructing a language: A usage-based theory of language acquisition. Cambridge, MA: Harvard University Press]. However, further work on constructivist theory development is required to allow researchers to make predictions about the nature of these operations.

  4. Six Questions on Complex Systems

    NASA Astrophysics Data System (ADS)

    Symons, John F.; Sanayei, Ali

    2011-09-01

    This paper includes an interview with John F. Symons regarding some important questions in "complex systems" and "complexity". In addition, he has stated some important open problems concerning complex systems in his research area from a philosophical point of view.

  5. Interview Questions with Bentham Scientific

    NASA Technical Reports Server (NTRS)

    Mather, John C.

    2013-01-01

    John Mather answers questions for an interview for the Bentham Science Newsletter. He covers topics ranging from his childhood, his professional career and his thoughts on research, technology and today's scientists and engineers.

  6. HPV Vaccine - Questions and Answers

    MedlinePlus

    ... and Media Resources News Newsletters Events Redirect for HPV Vaccine FAQ Recommend on Facebook Tweet Share Compartir ... to the address below. http://www.cdc.gov/hpv/parents/questions-answers.html File Formats Help: How ...

  7. Solar physics: Dynamo theory questioned

    NASA Astrophysics Data System (ADS)

    Charbonneau, Paul

    2016-07-01

    Observations of X-ray emission -- a diagnostic tool for the mechanisms driving stellar magnetic fields -- from four cool stars call into question accepted models of magnetic-field generation in the Sun and stars. See Letter p.526

  8. Questions to Ask Your Doctor

    MedlinePlus

    ... Donate Home > Education > Questions to Ask Your Doctor Education What is mbc? Diagnosis Guide for the Newly ... treatment in a community-based medical office. Consider distance from home, availability of specialists, access to clinical ...

  9. Questions Students Ask: Beta Decay.

    ERIC Educational Resources Information Center

    Koss, Jordan; Hartt, Kenneth

    1988-01-01

    Answers a student's question about the emission of a positron from a nucleus. Discusses the problem from the aspects of the uncertainty principle, beta decay, the Fermi Theory, and modern physics. (YP)

  10. Birds: Old Questions and New.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    2002-01-01

    Discusses questions such as how birds fly and the meaning of bird songs. Explains the relationship between birds and ecological activism and points out the excitement in research and observation of birds. (Contains 34 references.) (YDS)

  11. Darwin, Cuvier and Geoffroy: comments and questions.

    PubMed

    Grene, M

    2001-01-01

    In writing, in the Origin of Species, of 'two great laws' on which organic beings are formed, 'Unity of Type' and 'Conditions of Existence', Darwin was referring to the famous opposition between Cuvier and Geoffroy Saint-Hilaire, first stated publicly in the spring of 1830. After a brief statement of the chief points at issue in the debate, I raise the question of Darwin's attitude to the disagreement and the views of the two protagonists. There are numerous earlier, and some later, references to Cuvier and Geoffroy in the Darwin archives, notebooks, marginalia and correspondence. An examination of these materials suggests a shift in Darwin's sympathies, from Geoffroy to Cuvier. However, some of Geoffroy's principles are retained, and, in adopting Cuvier's phrase 'conditions of existence', Darwin partly alters its meaning. Finally, since originally, and in its adoption by such writers as Whewell and Owen, the expression 'conditions of existence' was interpreted as entailing design or final cause, I consider the vexed question of Darwin's attitude to teleology. PMID:12557693

  12. Cosmic Origin and Theology of the Revelation

    NASA Astrophysics Data System (ADS)

    Guijarro, José Francisco

    2007-04-01

    All along cultural history man has asked himself about the origin of man, the origin of life ante the origin of the cosmos. Regarding the question about the origin of the cosmos, any theological research must settle before any other goal the question of its language: what we understand as scientific, mythical or theological language. The biblical texts on Creation are analyzed in their historical, cultural and theological context. It is concluded that the fundamental religious meanings of the biblical texts are not in opposition to scientific interpretation of cosmic origin.

  13. Disability Discrimination and Obesity: The Big Questions?

    PubMed

    Flint, Stuart W; Snook, Jeremé

    2015-12-01

    Obesity discrimination in employment and recruitment has become a topic of focus for research examination with increasing reports of discrimination by colleagues and managers. Whilst a limited number of legal cases have emerged, disability law is consulted in line with the expectation of anti-discriminatory practices at work. In line with disability law, whether obesity is defined as a disability or not has an impact on the outcome of a court ruling. Ambiguity when defining obesity through either the medical or social model means there are many questions that remain unanswered which might lead to inconsistency in court rulings. PMID:26353881

  14. Disability Discrimination and Obesity: The Big Questions?

    PubMed

    Flint, Stuart W; Snook, Jeremé

    2015-12-01

    Obesity discrimination in employment and recruitment has become a topic of focus for research examination with increasing reports of discrimination by colleagues and managers. Whilst a limited number of legal cases have emerged, disability law is consulted in line with the expectation of anti-discriminatory practices at work. In line with disability law, whether obesity is defined as a disability or not has an impact on the outcome of a court ruling. Ambiguity when defining obesity through either the medical or social model means there are many questions that remain unanswered which might lead to inconsistency in court rulings.

  15. Science questions for the Magellan continuing mission

    NASA Technical Reports Server (NTRS)

    Saunders, R. S.; Stofan, E. R.

    1992-01-01

    Magellan has completed two mapping cycles around the planet Venus, returning high resolution synthetic aperture images and altimetry data of over 95 percent of the planet's surface. Venus is dominated by low lying volcanic plains with an impact crater population indicating an average surface age of about 500 million years. Highland regions either tend to be characterized by volcanic shield complexes and rifting or by complex ridged terrain. Successful as the primary mission of Magellan has been, significant scientific questions remain to be addressed with imaging and gravity data that will be collected over the next several years.

  16. Quantifying the origins of life on a planetary scale

    NASA Astrophysics Data System (ADS)

    Scharf, Caleb; Cronin, Leroy

    2016-07-01

    A simple, heuristic formula with parallels to the Drake Equation is introduced to help focus discussion on open questions for the origins of life in a planetary context. This approach indicates a number of areas where quantitative progress can be made on parameter estimation for determining origins of life probabilities, based on constraints from Bayesian approaches. We discuss a variety of “microscale” factors and their role in determining “macroscale” abiogenesis probabilities on suitable planets. We also propose that impact ejecta exchange between planets with parallel chemistries and chemical evolution could in principle amplify the development of molecular complexity and abiogenesis probabilities. This amplification could be very significant, and both bias our conclusions about abiogenesis probabilities based on the Earth and provide a major source of variance in the probability of life arising in planetary systems. We use our heuristic formula to suggest a number of observational routes for improving constraints on origins of life probabilities.

  17. Quantifying the origins of life on a planetary scale.

    PubMed

    Scharf, Caleb; Cronin, Leroy

    2016-07-19

    A simple, heuristic formula with parallels to the Drake Equation is introduced to help focus discussion on open questions for the origins of life in a planetary context. This approach indicates a number of areas where quantitative progress can be made on parameter estimation for determining origins of life probabilities, based on constraints from Bayesian approaches. We discuss a variety of "microscale" factors and their role in determining "macroscale" abiogenesis probabilities on suitable planets. We also propose that impact ejecta exchange between planets with parallel chemistries and chemical evolution could in principle amplify the development of molecular complexity and abiogenesis probabilities. This amplification could be very significant, and both bias our conclusions about abiogenesis probabilities based on the Earth and provide a major source of variance in the probability of life arising in planetary systems. We use our heuristic formula to suggest a number of observational routes for improving constraints on origins of life probabilities.

  18. Quantifying the origins of life on a planetary scale.

    PubMed

    Scharf, Caleb; Cronin, Leroy

    2016-07-19

    A simple, heuristic formula with parallels to the Drake Equation is introduced to help focus discussion on open questions for the origins of life in a planetary context. This approach indicates a number of areas where quantitative progress can be made on parameter estimation for determining origins of life probabilities, based on constraints from Bayesian approaches. We discuss a variety of "microscale" factors and their role in determining "macroscale" abiogenesis probabilities on suitable planets. We also propose that impact ejecta exchange between planets with parallel chemistries and chemical evolution could in principle amplify the development of molecular complexity and abiogenesis probabilities. This amplification could be very significant, and both bias our conclusions about abiogenesis probabilities based on the Earth and provide a major source of variance in the probability of life arising in planetary systems. We use our heuristic formula to suggest a number of observational routes for improving constraints on origins of life probabilities. PMID:27382156

  19. Quantifying the origins of life on a planetary scale

    PubMed Central

    Scharf, Caleb; Cronin, Leroy

    2016-01-01

    A simple, heuristic formula with parallels to the Drake Equation is introduced to help focus discussion on open questions for the origins of life in a planetary context. This approach indicates a number of areas where quantitative progress can be made on parameter estimation for determining origins of life probabilities, based on constraints from Bayesian approaches. We discuss a variety of “microscale” factors and their role in determining “macroscale” abiogenesis probabilities on suitable planets. We also propose that impact ejecta exchange between planets with parallel chemistries and chemical evolution could in principle amplify the development of molecular complexity and abiogenesis probabilities. This amplification could be very significant, and both bias our conclusions about abiogenesis probabilities based on the Earth and provide a major source of variance in the probability of life arising in planetary systems. We use our heuristic formula to suggest a number of observational routes for improving constraints on origins of life probabilities. PMID:27382156

  20. The Media Effects Question: "Unresolvable" or Asking the Right Question.

    ERIC Educational Resources Information Center

    Morrison, Gary R.

    1994-01-01

    Critiques articles by Robert Kozma (IR 529 138) and Richard Clark (EJ 294 173) on the influence of media on learning. The author argues that Clark and Kozma are raising different questions and suggests that researchers focus on the effectiveness of whole units of instruction rather than on individual components. (Contains 14 references.) (KRN)

  1. Deep Question Answering for protein annotation.

    PubMed

    Gobeill, Julien; Gaudinat, Arnaud; Pasche, Emilie; Vishnyakova, Dina; Gaudet, Pascale; Bairoch, Amos; Ruch, Patrick

    2015-01-01

    Biomedical professionals have access to a huge amount of literature, but when they use a search engine, they often have to deal with too many documents to efficiently find the appropriate information in a reasonable time. In this perspective, question-answering (QA) engines are designed to display answers, which were automatically extracted from the retrieved documents. Standard QA engines in literature process a user question, then retrieve relevant documents and finally extract some possible answers out of these documents using various named-entity recognition processes. In our study, we try to answer complex genomics questions, which can be adequately answered only using Gene Ontology (GO) concepts. Such complex answers cannot be found using state-of-the-art dictionary- and redundancy-based QA engines. We compare the effectiveness of two dictionary-based classifiers for extracting correct GO answers from a large set of 100 retrieved abstracts per question. In the same way, we also investigate the power of GOCat, a GO supervised classifier. GOCat exploits the GOA database to propose GO concepts that were annotated by curators for similar abstracts. This approach is called deep QA, as it adds an original classification step, and exploits curated biological data to infer answers, which are not explicitly mentioned in the retrieved documents. We show that for complex answers such as protein functional descriptions, the redundancy phenomenon has a limited effect. Similarly usual dictionary-based approaches are relatively ineffective. In contrast, we demonstrate how existing curated data, beyond information extraction, can be exploited by a supervised classifier, such as GOCat, to massively improve both the quantity and the quality of the answers with a +100% improvement for both recall and precision. Database URL: http://eagl.unige.ch/DeepQA4PA/. PMID:26384372

  2. Deep Question Answering for protein annotation.

    PubMed

    Gobeill, Julien; Gaudinat, Arnaud; Pasche, Emilie; Vishnyakova, Dina; Gaudet, Pascale; Bairoch, Amos; Ruch, Patrick

    2015-01-01

    Biomedical professionals have access to a huge amount of literature, but when they use a search engine, they often have to deal with too many documents to efficiently find the appropriate information in a reasonable time. In this perspective, question-answering (QA) engines are designed to display answers, which were automatically extracted from the retrieved documents. Standard QA engines in literature process a user question, then retrieve relevant documents and finally extract some possible answers out of these documents using various named-entity recognition processes. In our study, we try to answer complex genomics questions, which can be adequately answered only using Gene Ontology (GO) concepts. Such complex answers cannot be found using state-of-the-art dictionary- and redundancy-based QA engines. We compare the effectiveness of two dictionary-based classifiers for extracting correct GO answers from a large set of 100 retrieved abstracts per question. In the same way, we also investigate the power of GOCat, a GO supervised classifier. GOCat exploits the GOA database to propose GO concepts that were annotated by curators for similar abstracts. This approach is called deep QA, as it adds an original classification step, and exploits curated biological data to infer answers, which are not explicitly mentioned in the retrieved documents. We show that for complex answers such as protein functional descriptions, the redundancy phenomenon has a limited effect. Similarly usual dictionary-based approaches are relatively ineffective. In contrast, we demonstrate how existing curated data, beyond information extraction, can be exploited by a supervised classifier, such as GOCat, to massively improve both the quantity and the quality of the answers with a +100% improvement for both recall and precision. Database URL: http://eagl.unige.ch/DeepQA4PA/.

  3. Fundamental questions relating to ion conduction in disordered solids

    NASA Astrophysics Data System (ADS)

    Dyre, Jeppe C.; Maass, Philipp; Roling, Bernhard; Sidebottom, David L.

    2009-04-01

    A number of basic scientific questions relating to ion conduction in homogeneously disordered solids are discussed. The questions deal with how to define the mobile ion density, what can be learnt from electrode effects, what the ion transport mechanism is, the role of dimensionality and what the origins of the mixed-alkali effect, the time-temperature superposition, and the nearly constant loss are. Answers are suggested to some of these questions, but the main purpose of the paper is to draw attention to the fact that this field of research still presents several fundamental challenges.

  4. Response times to conceptual questions

    NASA Astrophysics Data System (ADS)

    Lasry, Nathaniel; Watkins, Jessica; Mazur, Eric; Ibrahim, Ahmed

    2013-09-01

    We measured the time taken by students to respond to individual Force Concept Inventory (FCI) questions. We examine response time differences between correct and incorrect answers, both before and after instruction. We also determine the relation between response time and expressed confidence. Our data reveal three results of interest. First, response times are longer for incorrect answers than for correct ones, indicating that distractors are not automatic choices. Second, response times increase after instruction for both correct and incorrect answers, supporting the notion that instruction changes students' approach to conceptual questions. Third, response times are inversely related to students' expressed confidence; the lower their confidence, the longer it takes to respond.

  5. Original Version

    Cancer.gov

    The EPEC-O (Education in Palliative and End-of-Life Care for Oncology) Self-Study Original Version is a free comprehensive multimedia curricula for health professionals caring for persons with cancer and their families. The curricula is available as an online Self-Study Section and as a CD-ROM you can order.

  6. Addressing Phonological Questions with Ultrasound

    ERIC Educational Resources Information Center

    Davidson, Lisa

    2005-01-01

    Ultrasound can be used to address unresolved questions in phonological theory. To date, some studies have shown that results from ultrasound imaging can shed light on how differences in phonological elements are implemented. Phenomena that have been investigated include transitional schwa, vowel coalescence, and transparent vowels. A study of…

  7. Constructivism and Objectivism: Additional Questions

    ERIC Educational Resources Information Center

    Meltzer, Edmund S.

    2006-01-01

    In past issues of "The Educational Forum," David Elkind (2004; 2005) and Jamin Carson (2005) have engaged in a dialogue about constructivism and objectivism as viable philosophies of education. In this issue, yet another author joins in the discussion by questioning the role of science and religion in objectivism.

  8. Ten Practical Questions about Branding

    ERIC Educational Resources Information Center

    Moore, Robert M.; Rattenbury, Jeanne

    2004-01-01

    "Marketing" and "branding" were once considered dirty words on campus but faculty, staff, and board members now appreciate the value of getting their message out and managing their reputation. The question is not so much whether to invest, but when, how, and most important, what's the return on investment? A roundtable of accomplished marketing…

  9. Explaining Errors in Children's Questions

    ERIC Educational Resources Information Center

    Rowland, Caroline F.

    2007-01-01

    The ability to explain the occurrence of errors in children's speech is an essential component of successful theories of language acquisition. The present study tested some generativist and constructivist predictions about error on the questions produced by ten English-learning children between 2 and 5 years of age. The analyses demonstrated that,…

  10. The Geography of Virtual Questioning

    ERIC Educational Resources Information Center

    Mon, Lorri; Bishop, Bradley Wade; McClure, Charles R.; McGilvray, Jessica; Most, Linda; Milas, Theodore Patrick; Snead, John T.

    2009-01-01

    This article explores the geography of virtual questioning by using geographic information systems to study activity within the Florida Electronic Library "Ask a Librarian" collaborative chat service. Researchers mapped participating libraries throughout the state of Florida that served as virtual "entry portals" for users as they asked questions…

  11. Questionable Methods in Alcoholism Research.

    ERIC Educational Resources Information Center

    Koocher, Gerald P.

    1991-01-01

    Alcoholism research paradigms that use substantial cash incentives to attract participants and that call for alcoholics to consume ethanol in laboratory raise ethical questions. When using such methods, investigators should be obligated to discuss risk-benefit rationales and detail precautionary behaviors to protect participants. Discussion of…

  12. Some Questions for Feminist Rhetoric.

    ERIC Educational Resources Information Center

    Hayes, Christopher G.

    Some questions about feminist rhetoric would include the following. Should a speaker resist the phallocentric rhetoric of the academy by refusing, resisting or otherwise willfully choosing not to say, "Here are my points, Here are my conclusions, Here is my argument that I hope to persuade you to believe?" Should a speaker foster a discourse that…

  13. Looming Questions in Performance Pay

    ERIC Educational Resources Information Center

    Gratz, Donald B.

    2010-01-01

    When proposing performance pay for teachers, reformers first must answer three questions: What is the definition of teacher performance? What is the definition of student performance? and What are the goals of schooling? Reformers also need to examine the assumptions that guide their proposals and prepare to deal with the implementation issues…

  14. Four Questions to Ask Yourself

    ERIC Educational Resources Information Center

    Abilock, Debbie, Ed.

    2007-01-01

    One's commitment to intellectual freedom is manifested not just in the creation of a strong and clear selection policy or the celebration of Banned Books Week but by his or her willingness to examine his or her practices openly with others. In this article, the author proposes four questions to explore in one's teaching and in professional…

  15. Origin of Tektites.

    PubMed

    O'keefe, J A; Shute, B E

    1963-03-29

    A comet of the size recently postulated by H. C. Urey would leave a large crater. It is shown, from aerodynamic theory, from observations of distribution around terrestrial impact craters, and from experimental nuclear explosions, that the observed distribution of tektites cannot be the result of impact on the earth, whether cometary or meteoritic. It is further shown, from aerodynamic theory, from observation of a meteor shower, and from study of the breakup of artificial satellites, that the distribution of tektites can be accounted for as a result of fusion stripping of a satellite, as originally suggested by Suess. PMID:17757065

  16. Origin of Tektites.

    PubMed

    O'keefe, J A; Shute, B E

    1963-03-29

    A comet of the size recently postulated by H. C. Urey would leave a large crater. It is shown, from aerodynamic theory, from observations of distribution around terrestrial impact craters, and from experimental nuclear explosions, that the observed distribution of tektites cannot be the result of impact on the earth, whether cometary or meteoritic. It is further shown, from aerodynamic theory, from observation of a meteor shower, and from study of the breakup of artificial satellites, that the distribution of tektites can be accounted for as a result of fusion stripping of a satellite, as originally suggested by Suess.

  17. The origin of the constellations

    NASA Astrophysics Data System (ADS)

    Roy, Archie E.

    The problem of the origin of the stellar constellations familiar to western astronomers from ancient times is discussed in an attempt to answer the classical detective story questions: Who? When? Why? and Where? The available astronomical, literary and archaeological evidence is examined to suggest a possible solution.

  18. Common questions in veterinary toxicology.

    PubMed

    Bates, N; Rawson-Harris, P; Edwards, N

    2015-05-01

    Toxicology is a vast subject. Animals are exposed to numerous drugs, household products, plants, chemicals, pesticides and venomous animals. In addition to the individual toxicity of the various potential poisons, there is also the question of individual response and, more importantly, of species differences in toxicity. This review serves to address some of the common questions asked when dealing with animals with possible poisoning, providing evidence where available. The role of emetics, activated charcoal and lipid infusion in the management of poisoning in animals, the toxic dose of chocolate, grapes and dried fruit in dogs, the use of antidotes in paracetamol poisoning, timing of antidotal therapy in ethylene glycol toxicosis and whether lilies are toxic to dogs are discussed. PMID:25728477

  19. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  20. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  1. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  2. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  3. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  4. Let's Start at the Very Beginning: The Impact of Program Origins and Negotiated Community-University Partnerships on Canadian Radical Humanities Programs

    ERIC Educational Resources Information Center

    Groen, Janet; Hyland-Russell, Tara

    2012-01-01

    This article examines the community-university partnerships and the planning process of three Canadian Radical Humanities programs: programs that offer university entry-level humanities to adult learners on the margins of society. Examining these three iterations has revealed the significance of program origins, particularly the introduction of…

  5. Frequently Asked Questions about Population.

    ERIC Educational Resources Information Center

    California Journal of Science Education, 2000

    2000-01-01

    Emphasizes the issue of human population growth. Provides information on current demographic trends; their social, economic, and environmental impacts; and Zero Population Growth's (ZPG) position on several controversial topics. (ASK)

  6. Five questions to ask about the soils

    NASA Astrophysics Data System (ADS)

    Kasanin Grubin, Milica

    2013-04-01

    I think that anyone who ever gave a lecture would agree that this feels like being on a stage. One has to educate the audience of course, but also keep attention and be interesting to the listeners. Authority is important but there is a certain vulnerability at all times. There is also a fine line on both sides that should not be crossed. However, the most important thing is that the audience remembers the lecture and certain points the lecturer made for at least some time, and even more that someone gets interested enough to ask for more details. This is often done by giving interesting examples and unusual comparison. Teaching a soils course there are five main questions to be addressed, of which first four are often subordinated to the fifth being the most complex. First question is "Is the soil alive?". The answer is yes, and that is what it differentiates from any type of sediment or rock, and it is very vulnerable to environmental change. The second question is "Where does it come from?" Rocks being a main origin of soils are often neglected in soil science and petrography in general, and weathering, as an important process for soil formation, are not given enough explaining. Petrography teaches us about rock characteristics, structure and texture and mineralogy. Understanding petrography would help in understanding the weathering processes which are crucial for soil formation and this must not be ignored. The third question is "Is it old?" Yes, it is - at least for everybody else except geologists. It is important to understand how slow the soil formation process is. The forth question is "Does it move?" Yes, it can move and the faster it moves downhill, it less likes it. Erosion is a very important problem for soil and must be addressed. And finally, the fifth question is "What are the main characteristics of soils?" This is an opportunity to talk about physical, chemical, biological, microbiological issues. As the most elaborate question it allows the

  7. Questions and answers based on revised 10 CFR Part 20

    SciTech Connect

    Borges, T.; Stafford, R.S.; Lu, P.Y.; Carter, D.

    1994-05-01

    NUREG/CR-6204 is a collection of questions and answers that were originally issued in seven sets and which pertain to revised 10 CFR Part 20. The questions came from both outside and within the NRC. The answers were compiled and provided by NRC staff within the offices of Nuclear Reactor Regulation, Nuclear Material Safety and Safeguards, Nuclear Regulatory Research, the Office of State Programs, and the five regional offices. Although all of the questions and answers have been reviewed by attorneys in the NRC Office of the General Counsel, they do not constitute official legal interpretations relevant to revised 10 CFR Part 20. The questions and answers do, however, reflect NRC staff decisions and technical options on aspects of the revised 10 CFR Part 20 regulatory requirements. This NUREG is being made available to encourage communication among the public, industry, and NRC staff concerning the major revisions of the NRC`s standards for protection against radiation.

  8. Effects of question formats on causal judgments and model evaluation

    PubMed Central

    Smithson, Michael

    2015-01-01

    Evaluation of causal reasoning models depends on how well the subjects’ causal beliefs are assessed. Elicitation of causal beliefs is determined by the experimental questions put to subjects. We examined the impact of question formats commonly used in causal reasoning research on participant’s responses. The results of our experiment (Study 1) demonstrate that both the mean and homogeneity of the responses can be substantially influenced by the type of question (structure induction versus strength estimation versus prediction). Study 2A demonstrates that subjects’ responses to a question requiring them to predict the effect of a candidate cause can be significantly lower and more heterogeneous than their responses to a question asking them to diagnose a cause when given an effect. Study 2B suggests that diagnostic reasoning can strongly benefit from cues relating to temporal precedence of the cause in the question. Finally, we evaluated 16 variations of recent computational models and found the model fitting was substantially influenced by the type of questions. Our results show that future research in causal reasoning should place a high priority on disentangling the effects of question formats from the effects of experimental manipulations, because that will enable comparisons between models of causal reasoning uncontaminated by method artifact. PMID:25954225

  9. Effects of question formats on causal judgments and model evaluation.

    PubMed

    Shou, Yiyun; Smithson, Michael

    2015-01-01

    Evaluation of causal reasoning models depends on how well the subjects' causal beliefs are assessed. Elicitation of causal beliefs is determined by the experimental questions put to subjects. We examined the impact of question formats commonly used in causal reasoning research on participant's responses. The results of our experiment (Study 1) demonstrate that both the mean and homogeneity of the responses can be substantially influenced by the type of question (structure induction versus strength estimation versus prediction). Study 2A demonstrates that subjects' responses to a question requiring them to predict the effect of a candidate cause can be significantly lower and more heterogeneous than their responses to a question asking them to diagnose a cause when given an effect. Study 2B suggests that diagnostic reasoning can strongly benefit from cues relating to temporal precedence of the cause in the question. Finally, we evaluated 16 variations of recent computational models and found the model fitting was substantially influenced by the type of questions. Our results show that future research in causal reasoning should place a high priority on disentangling the effects of question formats from the effects of experimental manipulations, because that will enable comparisons between models of causal reasoning uncontaminated by method artifact.

  10. The impact of geographical origin of two strains of the herbivore, Eccritotarsus catarinensis, on several fitness traits in response to temperature.

    PubMed

    Ismail, Mohannad; Brooks, Margot

    2016-08-01

    Adaptation to temperature changes is vital to reduce adverse effects on individuals, and some may present phenotypic changes, which might be accompanied with physiological costs in fitness traits. The objective of this study was to determine whether the two strains of the herbivore Eccritotarsus catarinensis, a biological control agent against water hyacinth in South Africa, differ in their responses to temperature according to their geographical origin. We experimentally quantified the responses of the two strains, at three constant temperatures: 20°C, 25°C and 30°C, using laboratory cultures that originated from Brazil and Peru, where climates differ. Reproductive output, egg hatching rate, sex ratio and longevity were recorded at each temperature. Fitness traits for both strains were significantly reduced at 30°C compared with 25°C and 20°C in two successive generations. Nonetheless, Peruvian individuals continued their development at 30°C, whereas Brazilian individuals that succeeded in emerging did not continue their development. In contrast, sex ratio was unaffected by temperature. The Peruvian strain of E. catarinensis presented different phenotypes depending on temperature and was more adapted to extreme high temperature than the Brazilian strain. The tropical origin of the population induces the insect to tolerate the extreme high temperature. We suggest that the Peruvian strain could be better suited for release to control water hyacinth in nature, particularly in regions where temperature is high. PMID:27503736

  11. Biology Question Generation from a Semantic Network

    NASA Astrophysics Data System (ADS)

    Zhang, Lishan

    Science instructors need questions for use in exams, homework assignments, class discussions, reviews, and other instructional activities. Textbooks never have enough questions, so instructors must find them from other sources or generate their own questions. In order to supply instructors with biology questions, a semantic network approach was developed for generating open response biology questions. The generated questions were compared to professional authorized questions. To boost students' learning experience, adaptive selection was built on the generated questions. Bayesian Knowledge Tracing was used as embedded assessment of the student's current competence so that a suitable question could be selected based on the student's previous performance. A between-subjects experiment with 42 participants was performed, where half of the participants studied with adaptive selected questions and the rest studied with mal-adaptive order of questions. Both groups significantly improved their test scores, and the participants in adaptive group registered larger learning gains than participants in the control group. To explore the possibility of generating rich instructional feedback for machine-generated questions, a question-paragraph mapping task was identified. Given a set of questions and a list of paragraphs for a textbook, the goal of the task was to map the related paragraphs to each question. An algorithm was developed whose performance was comparable to human annotators. A multiple-choice question with high quality distractors (incorrect answers) can be pedagogically valuable as well as being much easier to grade than open-response questions. Thus, an algorithm was developed to generate good distractors for multiple-choice questions. The machine-generated multiple-choice questions were compared to human-generated questions in terms of three measures: question difficulty, question discrimination and distractor usefulness. By recruiting 200 participants from

  12. No question about exciting questions in cell biology.

    PubMed

    Pollard, Thomas D

    2013-12-01

    Although we have a good grasp of many important processes in cell biology, including knowledge of many molecules involved and how they interact with each other, we still do not understand most of the dynamical features that are the essence of living systems. Fortunately, we now have the ability to dissect biological systems in enough detail to understand their dynamics, including the use of mathematical models to account for past observations and predict future experiments. This deep level of mechanistic understanding should be our goal—not simply to satisfy our scientific curiosity, but also to understand the causes of disease well enough to predict risks, make early diagnoses, and treat effectively. Many big questions remain to be answered before we reach this goal of understanding cellular dynamics.

  13. Evaluative Conditioning: The "How" Question.

    PubMed

    Jones, Christopher R; Olson, Michael A; Fazio, Russell H

    2010-01-01

    Evaluative conditioning (EC) refers to attitude formation or change toward an object due to that object's mere co-occurrence with another valenced object or objects. This chapter focuses on the "how" question, that is, the question of what cognitive processes intervene between mere co-occurrence and attitude formation or change. Though EC has typically been thought of as occurring through a single, albeit contentious, mechanism, we begin by pointing out that both the heterogeneity of EC methodologies and the abundance of inconsistent results suggest that multiple processes with different characteristics can produce EC. We describe how the earliest posited process of EC, Pavlovian conditioning or signal learning, is a valid mechanism of EC that appears to have operated in some experiments but is unlikely to have operated in others and also cannot account for various EC findings. We describe other mechanisms of EC, when they can be expected to occur, and what characteristics they have. We particularly focus our attention on a process model of EC we have recently introduced, the implicit misattribution model. Finally, we describe the implications of a multi-process view of EC, which we argue can help resolve theoretical controversies and further the application of EC as a practical intervention for influencing attitudes in various domains.

  14. Answering Key Fuel Cycle Questions

    SciTech Connect

    Piet, S.J.; Dixon, B.W.; Bennett, R.G.; Smith, J.D.; Hill, R.N.

    2004-10-03

    Given the range of fuel cycle goals and criteria, and the wide range of fuel cycle options, how can the set of options eventually be narrowed in a transparent and justifiable fashion? It is impractical to develop all options. We suggest an approach that starts by considering a range of goals for the Advanced Fuel Cycle Initiative (AFCI) and then posits seven questions, such as whether Cs and Sr isotopes should be separated from spent fuel and, if so, what should be done with them. For each question, we consider which of the goals may be relevant to eventually providing answers. The AFCI program has both ''outcome'' and ''process'' goals because it must address both waste already accumulating as well as completing the fuel cycle in connection with advanced nuclear power plant concepts. The outcome objectives are waste geologic repository capacity and cost, energy security and sustainability, proliferation resistance, fuel cycle economics, and safety. The process objectives are rea diness to proceed and adaptability and robustness in the face of uncertainties.

  15. Text-Based Questioning: A Comprehension Strategy to Build English Language Learners' Content Knowledge

    ERIC Educational Resources Information Center

    Taboada, Ana; Bianco, Sarah; Bowerman, Virginia

    2012-01-01

    Student-generated questions in relation to text were examined in two studies. Study I examined the impact of student questioning in relation to general vocabulary in English-Only Speakers (EOs) and English language learners (ELLs). Findings indicated that questioning predicted comprehension in the reading comprehension of both groups of readers,…

  16. Questions about Careers in Oceanography.

    ERIC Educational Resources Information Center

    Anderson, Aubrey L.

    Knowing the relationship of the ocean to man, the weather and climate, availability of resources from the ocean, use of the ocean in transporation, waste disposal, and defense, and developing an understanding of the impact on the oceans of human activity are all goals of oceanographers. The goal of this brochure is to provide concise informative…

  17. Questioning Intuition through Reflective Engagement

    ERIC Educational Resources Information Center

    Schmidt, Christopher D.

    2014-01-01

    Current literature on ethics and moral development focuses on discussion concerning the impact of intuition on moral decision-making. Through the use of student journal reflections over the course of one semester, this study utilized a grounded theory approach in order to explore and understand participant levels of awareness and understanding of…

  18. Origins of magnetospheric plasma

    SciTech Connect

    Moore, T.E. )

    1991-01-01

    A review is given of recent (1987-1990) progress in understanding of the origins of plasmas in the earth's magnetosphere. In counterpoint to the early supposition that geomagnetic phenomena are produced by energetic plasmas of solar origin, 1987 saw the publication of a provocative argument that accelerated ionospheric plasma could supply all magnetospheric auroral and ring current particles. Significant new developments of existing data sets, as well as the establishment of entirely new data sets, have improved the ability to identify plasma source regions and to track plasma through the magnetospheric system of boundary layers and reservoirs. These developments suggest that the boundary between ionospheric and solar plasmas, once taken to lie at the plasmapause, actually lies much nearer to the magnetopause. Defining this boundary as the surface where solar wind and ionosphere contribute equally to the plasma, it is referred to herein as the 'geopause'. It is now well established that the infusion of ionospheric O(+) plays a major role in the storm-time distention of the magnetotail and inflation of the inner magnetosphere. After more than two decades of observation and debate, the question remains whether magnetosheric are protons of solar or terrestrial origin. 161 refs.

  19. Answering Key Fuel Cycle Questions

    SciTech Connect

    Steven J. Piet; Brent W. Dixon; J. Stephen Herring; David E. Shropshire; Mary Lou Dunzik-Gougar

    2003-10-01

    The Advanced Fuel Cycle Initiative (AFCI) program has both “outcome” and “process” goals because it must address both waste already accumulating as well as completing the fuel cycle in connection with advanced nuclear power plant concepts. The outcome objectives are waste geological repository capacity and cost, energy security and sustainability, proliferation resistance, fuel cycle economics, and safety. The process objectives are readiness to proceed and adaptability and robustness in the face of uncertainties. A classic decision-making approach to such a multi-attribute problem would be to weight individual quantified criteria and calculate an overall figure of merit. This is inappropriate for several reasons. First, the goals are not independent. Second, the importance of different goals varies among stakeholders. Third, the importance of different goals is likely to vary with time, especially the “energy future.” Fourth, some key considerations are not easily or meaningfully quantifiable at present. Instead, at this point, we have developed 16 questions the AFCI program should answer and suggest an approach of determining for each whether relevant options improve meeting each of the program goals. We find that it is not always clear which option is best for a specific question and specific goal; this helps identify key issues for future work. In general, we suggest attempting to create as many win-win decisions (options that are attractive or neutral to most goals) as possible. Thus, to help clarify why the program is exploring the options it is, and to set the stage for future narrowing of options, we have developed 16 questions, as follows: · What are the AFCI program goals? · Which potential waste disposition approaches do we plan for? · What are the major separations, transmutation, and fuel options? · How do we address proliferation resistance? · Which potential energy futures do we plan for? · What potential external triggers do we

  20. Wolf presence in the ranch of origin: impacts on temperament and physiological responses of beef cattle following a simulated wolf encounter.

    PubMed

    Cooke, R F; Bohnert, D W; Reis, M M; Cappellozza, B I

    2013-12-01

    This experiment evaluated temperament, vaginal temperature, and plasma cortisol in beef cows from wolf-naïve and wolf-experienced origins that were subjected to a simulated wolf encounter. Multiparous, pregnant, nonlactating Angus-crossbreed cows from the Eastern Oregon Agricultural Research Center located near Burns, OR (CON; n = 50), and from a commercial operation near Council, ID (WLF; n = 50), were used. To date, grey wolves are not present around Burns, OR, and thus CON were naïve to wolves. Conversely, wolves are present around Council, ID, and WLF cows were selected from a herd that had experienced multiple confirmed wolf-predation episodes from 2008 to 2012. Following a 50-d commingling and adaptation period, CON and WLF cows were ranked by temperament, BW, and BCS and allocated to 5 groups (d 0; 10 CON and 10 WLF cows/group). Groups were individually subjected to the experimental procedures on d 2 (n = 3) and d 3 (n = 2). Before the simulated wolf encounter, cow temperament was assessed and blood samples and vaginal temperatures (using intravaginal data loggers) were collected (presimulation assessments). Cows were then sorted by origin, moved to 2 adjacent drylot pens (10 WLF and 10 CON cows/pen), and subjected to a simulated wolf encounter event for 20 min, which consisted of 1) cotton plugs saturated with wolf urine attached to the drylot fence, 2) continuous reproduction of wolf howls, and 3) 3 leashed dogs that were walked along the fence perimeter. Thereafter, WLF and CON cows were commingled and returned to the handling facility for postsimulation assessments, which were conducted immediately after exposure to wolf-urine-saturated cotton plugs, wolf howl reproduction, and 20-s exposure to the 3 dogs while being restrained in a squeeze chute. Chute score, temperament score, and plasma cortisol concentration increased (P ≤ 0.01) from pre- to postsimulation assessment in WLF but did not change in CON cows (P ≥ 0.19). Exit velocity decreased (P

  1. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  2. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  3. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  4. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  5. The Questioning Strategies Observation System (QSOS).

    ERIC Educational Resources Information Center

    Morse, Kevin R.; Davis, O. L., Jr.

    The Questioning Strategies Observation System (QSOS) is designed to record verbal behaviors occurring in the classroom which are associated with the teacher's use of questions. Twenty-four categories are used in three main sections: initiation of the question, response to the question, and reaction to the response. Under initiation, the categories…

  6. Five Strategies for Questioning with Intention

    ERIC Educational Resources Information Center

    Costa, Arthur L.; Kallick, Bena

    2015-01-01

    Masterful teachers don't just ask a lot of questions; they ask questions in a purposeful way. In this article, Costa and Kallick describe five strategies that can help teachers become more purposeful in designing and posing questions. One strategy is to plan questions that elicit student thinking at various cognitive levels, from simple recall of…

  7. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  8. Minister Peng answers correspondents' questions.

    PubMed

    1991-02-01

    Following a press conference where she presented the results of the 1990 census and the accomplishments of China's family planning program, Peng Peiyun, minister of the State Family Planning Commission, and other officials answered the questions of Chinese and foreign correspondents. Asked about the implementation of family planning in rural areas, Peng explained that while the 1-child policy has been followed, farmers with only 1 daughter have been allowed a second child. Nonetheless, the total fertility rate (TFR) of rural women has fallen bellow 4. On the issue of abortion, an official explained that for the past few years, there have been 10 million abortions annually. Abortion, however, is used only when contraception fails. Despite China's impressive achievements in curbing population growth, Peng noted that the country still faces serious problems. As the country enters its 8th 5-year plan, China will undergo a baby boom. An average of 17 million births each year is expected throughout the plan's duration. Peng acknowledged that the previous target of controlling China's population to 1.2 billion by the year 2000 will not be achieved. Under the new plan, which hopes to reduce the TFR from 2.35 in 1989 to 2.0 by the turn of the century, calls for the population to stabilize somewhere between 1.5 and 1.6 billion. Peng also answered questions concerning abuses by family planning workers. She stressed that China's family planning program is voluntary, although economic disincentives are used. Furthermore, Peng addressed issues concerning religion and family planning, infanticide, the safety of contraceptives, and concerns over the ageing of the population. PMID:12284670

  9. An abiotic origin for hydrocarbons in the Allan Hills 84001 martian meteorite through cooling of magmatic and impact-generated gases

    NASA Technical Reports Server (NTRS)

    Shock, E. L.

    2000-01-01

    Thermodynamic calculations of metastable equilibria were used to evaluate the potential for abiotic synthesis of aliphatic and polycyclic aromatic hydrocarbons (PAHs) in the martian meteorite Allan Hills (ALH) 84001. The calculations show that PAHs and normal alkanes could form metastably from CO, CO2, and H2 below approximately 250-300 degrees C during rapid cooling of trapped magmatic or impact-generated gases. Depending on temperature, bulk composition, and oxidation-reduction conditions, PAHs and normal alkanes can form simultaneously or separately. Moreover, PAHs can form at lower H/C ratios, higher CO/CO2 ratios, and higher temperatures than normal alkanes. Dry conditions with H/C ratios less than approximately 0.01-0.001 together with high CO/CO2 ratios also favor the formation of unalkylated PAHs. The observed abundance of PAHs, their low alkylation, and a variable but high aromatic to aliphatic ratio in ALH 84001 all correspond to low H/C and high CO/CO2 ratios in magmatic and impact gases and can be used to deduce spatial variations of these ratios. Some hydrocarbons could have been formed from trapped magmatic gases, especially if the cooling was fast enough to prevent reequilibration. We propose that subsequent impact heating(s) in ALH 84001 could have led to dissociation of ferrous carbonates to yield fine-grain magnetite, formation of a CO-rich local gas phase, reduction of water vapor to H2, reequilibration of the trapped magmatic gases, aromatization of hydrocarbons formed previously, and overprinting of the synthesis from magmatic gases, if any. Rapid cooling and high-temperature quenching of CO-, H2-rich impact gases could have led to magnetite-catalyzed hydrocarbon synthesis.

  10. Effect of Lecture Instruction on Student Performance on Qualitative Questions

    ERIC Educational Resources Information Center

    Heron, Paula R. L.

    2015-01-01

    The impact of lecture instruction on student conceptual understanding in physics has been the subject of research for several decades. Most studies have reported disappointingly small improvements in student performance on conceptual questions despite direct instruction on the relevant topics. These results have spurred a number of attempts to…

  11. Socratic Questioning in the Paideia Method to Encourage Dialogical Discussions

    ERIC Educational Resources Information Center

    Davies, Maree; Sinclair, Anne

    2014-01-01

    This study focused on the impact of using Socratic questioning, based on the Paideia Method, on the nature of middle-schools students' patterns of interaction and on the cognitive complexity of their discussions. The hypothesis is that an experimental group will increase in both interaction focus and complexity at T3, which is the…

  12. Questioning Technology in the Development of a Resilient Higher Education

    ERIC Educational Resources Information Center

    Hall, Richard; Winn, Joss

    2011-01-01

    This article considers the impact that peak oil and climate change may have on the future of higher education. In particular, it questions the role of technology in supporting the provision of a higher education which is resilient to a scenario both of energy depletion and the need to adapt to the effects of global warming. One emerging area of…

  13. Are Professors Professionals? A Fresh Look at This Question

    ERIC Educational Resources Information Center

    Newlyn, David

    2015-01-01

    Are university educators professionals? Whether or not university educators should be regarded as professionals is an important question that has an impact on a number of issues including job satisfaction, societal status and salary levels. This paper examines the need to classify this group as a profession and the consequences of that…

  14. Isotopic tracing of the impact of mobility on infectious disease: The origin of people with treponematosis buried in hull, England, in the late medieval period.

    PubMed

    Roberts, C A; Millard, A R; Nowell, G M; Gröcke, D R; Macpherson, C G; Pearson, D G; Evans, D H

    2013-02-01

    Treponematosis has been one of the most studied and debated infectious diseases in paleopathology, particularly from the standpoint of its origin, evolution, and transmission. This study links evidence for treponematosis in skeletons from the 14th-16th century AD cemetery of the Augustinian friary of Hull Magistrates Court, England, with data from stable isotope analysis to test the hypothesis that the people with treponemal disease buried at this site were not locally born and raised. The objective is to explore the potential of using stable isotope data to track the place of origin and extent of mobility of individuals with an infectious disease. Dental enamel samples of 12 skeletons were selected for strontium ((87) Sr/(86) Sr ratio) and oxygen (δ(18) O) stable isotope analysis based on the presence (six - diseased) or absence (six - controls) of bone changes associated with treponemal disease. The oxygen isotope ratios of all but three individuals (1047, 1121, 823) overlapped at two standard deviations with the inferred local precipitation range, and only one individual (1216) had a strontium isotope ratio outside the regional range. Two of the four had probable/possible treponemal bone changes. Those with treponemal bone changes were not demonstrably more likely to be migrants than those without such lesions. However, because of extensive documentary evidence for trade with the Baltic Sea area, and for merchants from towns such as Stralsund, Danzig and Elbing being in Hull, it is very plausible that the four migrants came from the Baltic area or even southern Sweden.

  15. Impact of origin and biological source on chemical composition, anticholinesterase and antioxidant properties of some St. John's wort species (Hypericum spp., Hypericaceae) from the Central Balkans.

    PubMed

    Božin, Biljana; Kladar, Nebojša; Grujić, Nevena; Anačkov, Goran; Samojlik, Isidora; Gavarić, Neda; Conić, Branislava Srđenović

    2013-09-25

    The study shows the influence of the origin of plant material and biological source on the in vitro antioxidant (neutralization of DPPH and OH radical, nitric oxide, and inhibition of lipid peroxidation) and anticholinesterase activity of chemically characterized and quantified ethanol extracts of ten St. John's wort samples. The investigated samples were: five Hypericum perforatum species representatives collected at different localities, one commercial sample of Hyperici herba purchased at a local market and four Hypericum species autochtonous to the Balkan Peninsula (H. maculatum subsp. immaculatum, H. olympicum, H. richeri subsp. grisebachii and H. barbatum). All the examined extracts exhibited notable antioxidant potential, but in most of the cases indigenous Hypericum species expressed stronger effects compared to the original source of the drug, H. perforatum. The changes in the content of phenolic compounds, especially flavonoids, hyperforin and hypericin, related to the source of the drug affected the investigated activities. Since all of the investigated species have shown prominent inhibition of acetylcholinesterase in vitro activity, they could be further investigated as potential substances in preventing of Alzheimer's disease.

  16. Different impact of heat-inactivated and viable lactic acid bacteria of aquatic origin on turbot (Scophthalmus maximus L.) head-kidney leucocytes.

    PubMed

    Muñoz-Atienza, Estefanía; Araújo, Carlos; Lluch, Nuria; Hernández, Pablo E; Herranz, Carmen; Cintas, Luis M; Magadán, Susana

    2015-05-01

    In aquaculture, several criteria should be considered to select an appropriate probiotic, including the aquatic origin and safety of the strain and its ability to modulate the host immune response. The properties and effects of probiotics are strain-specific and some factors such as viability, dose and duration of diet supplementation may regulate their immunomodulatory activities. In this study, we assessed the in vitro effect of eight heat-inactivated and viable lactic acid bacteria (LAB) of aquatic origin belonging to the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus and Weissella on the viability and innate immune response of turbot (Scophthalmus maximus L.) leucocytes. Head-kidney leucocytes were incubated with viable and heat-inactivated LAB at different concentrations. After incubation, the viability of leucocytes was evaluated using colorimetric assays (MTT and LDH) and flow cytometry (annexin V/propidium iodide). Heat-inactivated LAB showed no cytotoxic effect while viable LAB exerted variable influence on apoptosis of turbot phagocytes and lymphocytes. Leucocyte respiratory burst activity and phagocytosis were also differentially activated, as viable LAB stimulated leucocytes more efficiently than the heat-inactivated LAB. Our results suggest diverse strain-specific mechanisms of interaction between the evaluated LAB and turbot leucocytes. Furthermore, our work sets up in vitro systems to evaluate the effect of LAB as potential probiotics, which will be useful to develop efficient screening.

  17. Different impact of heat-inactivated and viable lactic acid bacteria of aquatic origin on turbot (Scophthalmus maximus L.) head-kidney leucocytes.

    PubMed

    Muñoz-Atienza, Estefanía; Araújo, Carlos; Lluch, Nuria; Hernández, Pablo E; Herranz, Carmen; Cintas, Luis M; Magadán, Susana

    2015-05-01

    In aquaculture, several criteria should be considered to select an appropriate probiotic, including the aquatic origin and safety of the strain and its ability to modulate the host immune response. The properties and effects of probiotics are strain-specific and some factors such as viability, dose and duration of diet supplementation may regulate their immunomodulatory activities. In this study, we assessed the in vitro effect of eight heat-inactivated and viable lactic acid bacteria (LAB) of aquatic origin belonging to the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus and Weissella on the viability and innate immune response of turbot (Scophthalmus maximus L.) leucocytes. Head-kidney leucocytes were incubated with viable and heat-inactivated LAB at different concentrations. After incubation, the viability of leucocytes was evaluated using colorimetric assays (MTT and LDH) and flow cytometry (annexin V/propidium iodide). Heat-inactivated LAB showed no cytotoxic effect while viable LAB exerted variable influence on apoptosis of turbot phagocytes and lymphocytes. Leucocyte respiratory burst activity and phagocytosis were also differentially activated, as viable LAB stimulated leucocytes more efficiently than the heat-inactivated LAB. Our results suggest diverse strain-specific mechanisms of interaction between the evaluated LAB and turbot leucocytes. Furthermore, our work sets up in vitro systems to evaluate the effect of LAB as potential probiotics, which will be useful to develop efficient screening. PMID:25707601

  18. Lac Télé structure, Republic of Congo: Geological setting of a cryptozoological and biodiversity hotspot, and evidence against an impact origin

    NASA Astrophysics Data System (ADS)

    Master, Sharad

    2010-11-01

    Lac Télé is a large lake, ˜5.6 km in diameter, with an ovoid shape, situated at 17°10'E, 1°20'N, in the great tropical rain forest region of the Republic of Congo. This lake has attracted widespread attention, mainly because of the legends among the local people that it harbours a strange animal known as the Mokele-Mbembe, but also because it is situated in a region that is a hotbed of biodiversity and conservation efforts with respect to various endangered mammalian species, including gorillas and chimpanzees. Because of its appearance, Lac Télé has been regarded as a possible meteorite impact structure. Various expeditions, studying cryptozoology, conservation ecology, biodiversity, and the impact hypothesis, have visited Lac Télé in the past several decades. The Lac Télé structure is located in the NW part of the intracratonic Congo Basin, in a region dominated by Holocene alluvium, dense tropical rain forest, and swamps which form part of the basin of the Likouala aux Herbes, a multi-branched meandering river flowing over very low gradients into the Sangha river, a major tributary of the Congo river. Previous bathymetric studies have shown that the average depth of Lac Télé is only 4 m, including organic-rich silty sediments. The structure is that of a flat-bottomed dish. Modelling of the Lac Télé as an impact structure indicates a number of features which ought to be present. The absence of any of these features, coupled with the irregular ovoid shape, the palynological record, and the location of the structure at the intersection of major regional lineaments, is regarded as evidence against the impact hypothesis. Lac Télé as an isolated lake ecosystem is not unique in the Congo Basin, and there are several other similar small shallow isolated lakes surrounded by rain forest and marshes, some of which formed by damming of drainage systems by neotectonic faults. It is suggested that the formation of Lac Télé may be related to its location

  19. Chemical Impact of Solar Energetic Particle Event From The Young Sun: Implications for the Origin of Prebiotic Chemistry and the Fain Young Sun Paradox

    NASA Astrophysics Data System (ADS)

    Airapetian, V.; Gronoff, G.; Hébrard, E.; Danchi, W.

    2015-12-01

    Understanding how the simple molecules present on the early Earth and possibly Mars may have set a path for complex biological molecules, the building blocks of life, represents one of greatest unsolved questions. Here we present a new model of the rise of the abiotic nitrogen fixation and associated pre-biotic chemistry in the early Earth and Mars atmosphere mediated by solar eruptive events. Our physical models of interaction of magnetic clouds ejected from the young Sun with magnetospheres of the early Earth show significant perturbations of geomagnetic fields that produce extended polar caps. These polar caps provide pathways for energetic particles associated with magnetic clouds to penetrate into the nitrogen-rich weakly reducing atmosphere and initiate the reactive chemistry by breaking molecular nitrogen, carbon dioxide, methane and producing hydrogen cyanide, the essential compound for life. The model also shows that contrary to the current models of warming of early Earth and Mars, major atmospheric constituents, CO2 and CH4 will be destroyed due to collisional dissociation with energetic particles. Instead, efficient formation of the potent greenhouse gas, nitrous oxide, as a by-product of these processes is expected. This mechanism can consistently explain the Faint Young Sun's paradox for the early atmospheres of Earth and Mars. Our new model provides insight into how life may have initiated on Earth and Mars and how to search for the spectral signatures on planets "pregnant" with the potential for life.

  20. Origin of Sex Revisited

    NASA Astrophysics Data System (ADS)

    Santos, Mauro; Zintzaras, Elias; Szathmáry, Eörs

    2003-10-01

    Why did sex ever arise in the first place? Why it does not disappear in view of the greater efficiency of asexuals? These are clearly two different questions, and we suggest here that the solution for the origin of sex does not necessarily come from theoretical considerations based on currently existing genetic systems. Thus, while we agree with a number of authors in that the emergence of sex (understood as the exchange of genetic material between genomes) is deeply rooted in the origin of life and happened during the very early stages in the transition from individual genes (`replicators') to bacteria-like cells (`reproducers'), we challenge the idea that recombinational repair was the major selective force for the emergence of sex. Taking the stochastic corrector model as a starting point, we provide arguments that question the putative costs of redundancy in primitive protocells. In addition, if genes that cause intragenomic conflict (i.e., parasites) are taken into account, it is certainly wrong to suggest that cellular fusion would be beneficial at the population level (although this strong claim needs some qualifications). However, when a continuous input of deleterious mutations that impair the fitness of the protocell as a whole is considered in the model (in the realistic range in which stable mutant distributions of quasi-species within compartments are established), there are circumstances when sex could be beneficial as a side effect of the dynamic equilibrium between cellular fusion-mutation-selection. The scenario we have explored numerically is fully consistent with the idea that the universal ancestor was not a discrete entity but an ensemble of proto-organisms that exchanged much genetic information.

  1. Basaltic glass formed from hydrovolcanism and impact processes: Characterization and clues for detection of mode of origin from VNIR through MWIR reflectance and emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Farrand, W. H.; Wright, S. P.; Rogers, A. D.; Glotch, T. D.

    2016-09-01

    The CheMin X-ray diffraction instrument on-board the Curiosity rover in Gale crater has measured a consistent X-ray amorphous component in drill core samples examined to-date, clearly demonstrating that X-ray amorphous materials are a significant fraction of the martian surface layer. Glasses are potential components of this amorphous material and in this study, basaltic tephras from several hydro- and glaciovolcanic centers, as well as impact melts from India's Lonar Crater, were examined using thin section petrography, visible and near-infrared reflectance and mid-wave infrared emission spectroscopy as well as measuring major and minor element chemistry of representative samples using X-ray fluorescence (XRF) spectroscopy. The objectives of this study have been to look for distinguishing characteristics between volcanic and impact glasses and to determine features that indicate whether the glasses are fresh or altered using methods available on current and planned Mars rovers. Spectral features in the visible and near-infrared (VNIR) that can be used as indicators of alteration include the development of hydration features at 1.9 and ∼3 μm and a feature attributed to ferric oxide development at 0.48 μm. In the mid-wave infrared, it was observed that glass-rich tephra field samples did not display a broad, disordered glass feature near 9-10 μm (as is observed in pristine basaltic glasses) but rather a doublet with centers near 9.5 and 11 μm attributed in earlier work to incipient devitrification into SiO4 chain and sheet structures respectively. A tentative observation was made that the Si-O bending feature, observed in all the sample spectra near 22 μm was broader in the hydro- and glaciovolcanic glass samples than in the impact glass samples. Hydro- and glaciovolcanic glass-rich tephra samples were used as library spectra in linear deconvolution analyses of Mars Global Surveyor Thermal Emission Spectrometer (MGS TES) surface spectral types. These

  2. Muddy and dolomitic rip-up clasts in Triassic fluvial sandstones: Origin and impact on potential reservoir properties (Argana Basin, Morocco)

    NASA Astrophysics Data System (ADS)

    Henares, Saturnina; Arribas, Jose; Cultrone, Giuseppe; Viseras, Cesar

    2016-06-01

    The significance of rip-up clasts as sandstone framework grains is frequently neglected in the literature being considered as accessory components in bulk sandstone composition. However, this study highlights the great value of muddy and dolomitic rip-up clast occurrence as: (a) information source about low preservation potential from floodplain deposits and (b) key element controlling host sandstone diagenetic evolution and thus ultimate reservoir quality. High-resolution petrographic analysis on Triassic fluvial sandstones from Argana Basin (T6 and T7/T8 units) highlights the significance of different types of rip-up clasts as intrabasinal framework components of continental sediments from arid climates. On the basis of their composition and ductility, three main types are distinguished: (a) muddy rip-up clasts, (b) dolomitic muddy rip-up clasts and (c) dolomite crystalline rip-up clasts. Spatial distribution of different types is strongly facies-related according to grain size. Origin of rip-up clasts is related to erosion of coeval phreatic dolocretes, in different development stages, and associated muddy floodplain sediments. Cloudy cores with abundant inclusions and clear outer rims of dolomite crystals suggest a first replacive and a subsequent displacive growth, respectively. Dolomite crystals are almost stoichiometric. This composition is very similar to that of early sandstone dolomite cement, supporting phreatic dolocretes as dolomite origin in both situations. Sandstone diagenesis is dominated by mechanical compaction and dolomite cementation. A direct correlation exists between: (1) muddy rip-up clast abundance and early reduction of primary porosity by compaction with irreversible loss of intergranular volume (IGV); and (2) occurrence of dolomitic rip-up clasts and dolomite cement nucleation in host sandstone, occluding adjacent pores but preserving IGV. Both processes affect reservoir quality by generation of vertical and 3D fluid flow baffles and

  3. Conducting systematic reviews of intervention questions I: Writing the review protocol, formulating the question and searching the literature.

    PubMed

    O'Connor, A M; Anderson, K M; Goodell, C K; Sargeant, J M

    2014-06-01

    This article is the fourth of six articles addressing systematic reviews in animal agriculture and veterinary medicine. Previous articles in the series have introduced systematic reviews, discussed study designs and hierarchies of evidence, and provided details on conducting randomized controlled trials, a common design for use in systematic reviews. This article describes development of a review protocol and the first two steps in a systematic review: formulating a review question, and searching the literature for relevant research. The emphasis is on systematic reviews of questions related to interventions. The review protocol is developed prior to conducting the review and specifies the plan for the conduct of the review, identifies the roles and responsibilities of the review team and provides structured definitions related to the review question. For intervention questions, the review question should be defined by the PICO components: population, intervention, comparison and outcome(s). The literature search is designed to identify all potentially relevant original research that may address the question. Search terms related to some or all of the PICO components are entered into literature databases, and searches for unpublished literature also are conducted. All steps of the literature search are documented to provide transparent reporting of the process.

  4. Does Question Structure Affect Exam Performance in the Geosciences?

    NASA Astrophysics Data System (ADS)

    Day, E. A.; D'Arcy, M. K.; Craig, L.; Streule, M. J.; Passmore, E.; Irving, J. C. E.

    2015-12-01

    The jump to university level exams can be challenging for some students, often resulting in poor marks, which may be detrimental to their confidence and ultimately affect their overall degree class. Previous studies have found that question structure can have a strong impact on the performance of students in college level exams (see Gibson et al., 2015, for a discussion of its impact on physics undergraduates). Here, we investigate the effect of question structure on the exam results of geology and geophysics undergraduate students. Specifically, we analyse the performance of students in questions that have a 'scaffolded' framework and compare them to their performance in open-ended questions and coursework. We also investigate if observed differences in exam performance are correlated with the educational background and gender of students, amongst other factors. It is important for all students to be able to access their degree courses, no matter what their backgrounds may be. Broadening participation in the geosciences relies on removing systematic barriers to achievement. Therefore we recommend that exams are either structured with scaffolding in questions at lower levels, or students are explicitly prepared for this transition. We also recommend that longitudinal studies of exam performance are conducted within individual departments, and this work outlines one approach to analysing performance data.

  5. Slipping through the cracks: the taxonomic impediment conceals the origin and dispersal of Haminoea japonica, an invasive species with impacts to human health.

    PubMed

    Hanson, Dieta; Cooke, Samantha; Hirano, Yayoi; Malaquias, Manuel A E; Crocetta, Fabio; Valdés, Ángel

    2013-01-01

    Haminoea japonica is a species of opisthobranch sea slug native to Japan and Korea. Non-native populations have spread unnoticed for decades due to difficulties in the taxonomy of Haminoea species. Haminoea japonica is associated with a schistosome parasite in San Francisco Bay, thus further spread could have consequence to human health and economies. Anecdotal evidence suggests that H. japonica has displaced native species of Haminoea in North America and Europe, becoming locally dominant in estuaries and coastal lagoons. In this paper we study the population genetics of native and non-native populations of H. japonica based on mt-DNA data including newly discovered populations in Italy and France. The conclusions of this study further corroborate a Northeastern Japan origin for the non-native populations and suggest possible independent introductions into North America and Europe. Additionally, the data obtained revealed possible secondary introductions within Japan. Although non-native populations have experienced severe genetic bottlenecks they have colonized different regions with a broad range of water temperatures and other environmental conditions. The environmental tolerance of this species, along with its ability to become dominant in invaded areas and its association with a schistosome parasite, suggest H. japonica could be a dangerous invasive species.

  6. Core questions in domestication research.

    PubMed

    Zeder, Melinda A

    2015-03-17

    The domestication of plants and animals is a key transition in human history, and its profound and continuing impacts are the focus of a broad range of transdisciplinary research spanning the physical, biological, and social sciences. Three central aspects of domestication that cut across and unify this diverse array of research perspectives are addressed here. Domestication is defined as a distinctive coevolutionary, mutualistic relationship between domesticator and domesticate and distinguished from related but ultimately different processes of resource management and agriculture. The relative utility of genetic, phenotypic, plastic, and contextual markers of evolving domesticatory relationships is discussed. Causal factors are considered, and two leading explanatory frameworks for initial domestication of plants and animals, one grounded in optimal foraging theory and the other in niche-construction theory, are compared.

  7. Indirect Review and Priming Through Questions

    ERIC Educational Resources Information Center

    Rothkopf, Ernst Z.; Billington, Marjorie J.

    1974-01-01

    The hypothesis that being questioned about a narrow topic while reading enhances the recall of other material closely related is supported. The relationship between the performances facilitating adjunct questions requires further explanation. (Author/BJG)

  8. Frequently Asked Questions (Palliative Care: Conversations Matter)

    MedlinePlus

    ... Questions Frequently Asked Questions: What is pediatric palliative care? Pediatric palliative (pal-lee-uh-tiv) care is ... for patients and families. Who provides pediatric palliative care? Every palliative care team is different. The team ...

  9. Provocative Questions in Cancer: NCI Seminar

    Cancer.gov

    science writers' seminar to discuss various aspects of one of NCI’s signature efforts -- the Provocative Questions project. Discussion will focus on the scientific research that surrounds some of these questions.

  10. The impact of emission power on the destruction of echo contrast agents and on the origin of tissue harmonic signals using power pulse-inversion imaging.

    PubMed

    Tiemann, K; Veltmann, C; Ghanem, A; Lohmaier, S; Bruce, M; Kuntz-Hehner, S; Pohl, C; Ehlgen, A; Schlosser, T; Omran, H; Becher, H

    2001-11-01

    The purpose of this study was to determine the impact of emission power on ultrasound (US)-induced destruction of echocontrast microbubbles during real-time power pulse inversion imaging (PPI) in myocardial contrast echocardiography (MCE) and to evaluate the magnitude of noncontrast PPI signals arising from myocardial tissue at variable emission power to define the cut-off emission power for optimal MCE using low power technologies. In vitro studies were performed in a flow phantom using Optison, Definity and AFO 150. PPI signal intensity during real-time imaging at 27 Hz was compared with intermittent imaging at 0.1 Hz to evaluate bubble destruction at variable emission power (MI: 0.09 to 1.3). In healthy volunteers, PPI signal intensities during constant infusion of Optison(R) was studied in real-time PPI 22 HZ and during intermittent imaging triggered end-systolic frames every, every 3rd and every 5th cardiac cycle. In addition, the impact of emission power on nonlinear PPI signals from myocardial structures was studied. In vitro, there was a 40% decrease of real-time PPI signal intensity for Optison and AFO 150 at lowest emission power (0.09), whereas no signal loss was observed for Definity. Increase of emission power resulted in a faster decay for Optison(R) and AFO 150 as compared to Definity. In vivo, real-time PPI during continuous infusion of Optison(R) resulted in a 40% decrease of myocardial signal intensity as compared to intermittent imaging every 5th cardiac cycle, even at lowest possible emission power (mechanical index = 0.09). There was a strong positive relationship between MI and noncontrast myocardial PPI signals in all myocardial segments. PPI signal intensity was found to be lower than 1 dB only for extremely low emission power (MI < 0.2). Destruction of microbubbles during real-time imaging by use of PPI at low emission power varies considerably for different echo contrast agents. However, bubble destruction and the onset of tissue harmonic

  11. Impact of sludge stabilization processes and sludge origin (urban or hospital) on the mobility of pharmaceutical compounds following sludge landspreading in laboratory soil-column experiments.

    PubMed

    Lachassagne, Delphine; Soubrand, Marilyne; Casellas, Magali; Gonzalez-Ospina, Adriana; Dagot, Christophe

    2015-11-01

    This study aimed to determine the effect of sludge stabilization treatments (liming and anaerobic digestion) on the mobility of different pharmaceutical compounds in soil amended by landspreading of treated sludge from different sources (urban and hospital). The sorption and desorption potential of the following pharmaceutical compounds: carbamazepine (CBZ), ciprofloxacin (CIP), sulfamethoxazole (SMX), salicylic acid (SAL), ibuprofen (IBU), paracetamol (PAR), diclofenac (DIC), ketoprofen (KTP), econazole (ECZ), atenolol (ATN), and their solid-liquid distribution during sludge treatment (from thickening to stabilization) were investigated in the course of batch testing. The different sludge samples were then landspread at laboratory scale and leached with an artificial rain simulating 1 year of precipitation adapted to the surface area of the soil column used. The quality of the resulting leachate was investigated. Results showed that ibuprofen had the highest desorption potential for limed and digested urban and hospital sludge. Ibuprofen, salicylic acid, diclofenac, and paracetamol were the only compounds found in amended soil leachates. Moreover, the leaching potential of these compounds and therefore the risk of groundwater contamination depend mainly on the origin of the sludge because ibuprofen and diclofenac were present in the leachates of soils amended with urban sludge, whereas paracetamol and salicylic acid were found only in the leachates of soils amended with hospital sludge. Although carbamazepine, ciprofloxacin, sulfamethoxazole, ketoprofen, econazole, and atenolol were detected in some sludge, they were not present in any leachate. This reflects either an accumulation and/or (bio)degradation of these compounds (CBZ, CIP, SMX, KTP, ECZ, and ATN ), thus resulting in very low mobility in soil. Ecotoxicological risk assessment, evaluated by calculating the risk quotients for each studied pharmaceutical compound, revealed no high risk due to the

  12. The impact of updated Zr neutron-capture cross sections and new asymptotic giant branch models on our understanding of the S process and the origin of stardust

    SciTech Connect

    Lugaro, Maria; Tagliente, Giuseppe; Karakas, Amanda I.; Milazzo, Paolo M.; Käppeler, Franz; Davis, Andrew M.; Savina, Michael R. E-mail: giuseppe.tagliente@ba.infn.it E-mail: paolo.milazzo@ts.infn.it E-mail: a-davis@uchicago.edu

    2014-01-01

    We present model predictions for the Zr isotopic ratios produced by slow neutron captures in C-rich asymptotic giant branch (AGB) stars of masses 1.25-4 M {sub ☉} and metallicities Z = 0.01-0.03, and compare them to data from single meteoritic stardust silicon carbide (SiC) and high-density graphite grains that condensed in the outflows of these stars. We compare predictions produced using the Zr neutron-capture cross sections from Bao et al. and from n{sub T}OF experiments at CERN, and present a new evaluation for the neutron-capture cross section of the unstable isotope {sup 95}Zr, the branching point leading to the production of {sup 96}Zr. The new cross sections generally present an improved match with the observational data, except for the {sup 92}Zr/{sup 94}Zr ratios, which are on average still substantially higher than predicted. The {sup 96}Zr/{sup 94}Zr ratios can be explained using our range of initial stellar masses, with the most {sup 96}Zr-depleted grains originating from AGB stars of masses 1.8-3 M {sub ☉} and the others from either lower or higher masses. The {sup 90,} {sup 91}Zr/{sup 94}Zr variations measured in the grains are well reproduced by the range of stellar metallicities considered here, which is the same needed to cover the Si composition of the grains produced by the chemical evolution of the Galaxy. The {sup 92}Zr/{sup 94}Zr versus {sup 29}Si/{sup 28}Si positive correlation observed in the available data suggests that stellar metallicity rather than rotation plays the major role in covering the {sup 90,} {sup 91,} {sup 92}Zr/{sup 94}Zr spread.

  13. Assessment of PM₂.₅ and PM₁ chemical profile in a multiple-impacted Mediterranean urban area: origin, sources and meteorological dependence.

    PubMed

    Pateraki, St; Asimakopoulos, D N; Bougiatioti, A; Maggos, Th; Vasilakos, Ch; Mihalopoulos, N

    2014-05-01

    Airborne particulate matter in the PM2.5 and PM1 size ranges has been sampled at three sites within the Mediterranean urban area of the Athens Basin, representing background, roadside-industrialized and coastal background locations. With the principal aim to identify the sources and discriminate the contribution of the regional input versus the local one, simultaneous chemical characterization with respect to carbonaceous and ionic species was also carried out on the collected samples. In general, the average recorded values were within the Mediterranean concentration range. The constant prevalence of the ionic mass (52%-79%) over one of the carbonaceous, being combined with the occurrence of its maximum rates at the coastal background environment (74%-79% and 73%-77% for PM2.5 and PM1, respectively) leads to the hypothesis that the fine PM pollution in the basin, especially for the remote locations, is evidently governed by the external intrusion. Even at the polluted atmosphere of the roadside-industrialized environment, the PM mass was regionally originated, with the corresponding input reaching up to 87% (northward flow). Applying factor analysis on the PM2.5 database it came obvious that the sources which were responsible for the configured PM burden were not fully differentiated not only between the different types of environment but also between the exceedances and the clean air events. The contribution of the secondary, marine and combustion processes was constant at all the stations of the network, while a continuous input of crustal particles characterized both the roadside-industrialized and the coastal atmosphere. Finally, the episodic values show a general common signal of secondary mixed ΡΜ emissions, high influence of both regional and local pollution spikes, confirming the earlier findings for the significance of transportation.

  14. Analysis of Glioblastoma Patients' Plasma Revealed the Presence of MicroRNAs with a Prognostic Impact on Survival and Those of Viral Origin

    PubMed Central

    Herman, Ana; Gruden, Kristina; Blejec, Andrej; Podpečan, Vid; Motaln, Helena; Rožman, Primož; Hren, Matjaž; Zupančič, Klemen; Veber, Matija; Verbovšek, Urška; Lah Turnšek, Tamara; Porčnik, Andrej; Koršič, Marjan; Knežević, Miomir; Jeras, Matjaž

    2015-01-01

    Background Glioblastoma multiforme (GBM) is among the most aggressive cancers with a poor prognosis in spite of a plethora of established diagnostic and prognostic biomarkers and treatment modalities. Therefore, the current goal is the detection of novel biomarkers, possibly detectable in the blood of GBM patients that may enable an early diagnosis and are potential therapeutic targets, leading to more efficient interventions. Experimental Procedures MicroRNA profiling of 734 human and human-associated viral miRNAs was performed on blood plasma samples from 16 healthy individuals and 16 patients with GBM, using the nCounter miRNA Expression Assay Kits. Results We identified 19 miRNAs with significantly different plasma levels in GBM patients, compared to the healthy individuals group with the difference limited by a factor of 2. Additionally, 11 viral miRNAs were found differentially expressed in plasma of GBM patients and 24 miRNA levels significantly correlated with the patients’ survival. Moreover, the overlap between the group of candidate miRNAs for diagnostic biomarkers and the group of miRNAs associated with survival, consisted of ten miRNAs, showing both diagnostic and prognostic potential. Among them, hsa miR 592 and hsa miR 514a 3p have not been previously described in GBM and represent novel candidates for selective biomarkers. The possible signalling, induced by the revealed miRNAs is discussed, including those of viral origin, and in particular those related to the impaired immune response in the progression of GBM. Conclusion The GBM burden is reflected in the alteration of the plasma miRNAs pattern, including viral miRNAs, representing the potential for future clinical application. Therefore proposed biomarker candidate miRNAs should be validated in a larger study of an independent cohort of patients. PMID:25950799

  15. Impact of sludge stabilization processes and sludge origin (urban or hospital) on the mobility of pharmaceutical compounds following sludge landspreading in laboratory soil-column experiments.

    PubMed

    Lachassagne, Delphine; Soubrand, Marilyne; Casellas, Magali; Gonzalez-Ospina, Adriana; Dagot, Christophe

    2015-11-01

    This study aimed to determine the effect of sludge stabilization treatments (liming and anaerobic digestion) on the mobility of different pharmaceutical compounds in soil amended by landspreading of treated sludge from different sources (urban and hospital). The sorption and desorption potential of the following pharmaceutical compounds: carbamazepine (CBZ), ciprofloxacin (CIP), sulfamethoxazole (SMX), salicylic acid (SAL), ibuprofen (IBU), paracetamol (PAR), diclofenac (DIC), ketoprofen (KTP), econazole (ECZ), atenolol (ATN), and their solid-liquid distribution during sludge treatment (from thickening to stabilization) were investigated in the course of batch testing. The different sludge samples were then landspread at laboratory scale and leached with an artificial rain simulating 1 year of precipitation adapted to the surface area of the soil column used. The quality of the resulting leachate was investigated. Results showed that ibuprofen had the highest desorption potential for limed and digested urban and hospital sludge. Ibuprofen, salicylic acid, diclofenac, and paracetamol were the only compounds found in amended soil leachates. Moreover, the leaching potential of these compounds and therefore the risk of groundwater contamination depend mainly on the origin of the sludge because ibuprofen and diclofenac were present in the leachates of soils amended with urban sludge, whereas paracetamol and salicylic acid were found only in the leachates of soils amended with hospital sludge. Although carbamazepine, ciprofloxacin, sulfamethoxazole, ketoprofen, econazole, and atenolol were detected in some sludge, they were not present in any leachate. This reflects either an accumulation and/or (bio)degradation of these compounds (CBZ, CIP, SMX, KTP, ECZ, and ATN ), thus resulting in very low mobility in soil. Ecotoxicological risk assessment, evaluated by calculating the risk quotients for each studied pharmaceutical compound, revealed no high risk due to the

  16. Informatics and Transborder Data Flow: The Question of Social Impact.

    ERIC Educational Resources Information Center

    Veith, Richard H.

    1980-01-01

    Summarizes what has been suggested so far with regard to the social, political, and economic consequences of transborder data flows involved in the linking of computerized information processing networks. (FM)

  17. The origins of research into the origins of life.

    PubMed

    Fry, Iris

    2006-03-01

    Most scientists at the end of the 19th and the beginning of the 20th century chose to ignore the question of the origin of life on Earth, regarding it as too mysterious and complex to handle. Yet, in the early 1950s an experimental field devoted to the study of the problem made its first steps. The pioneering theories of several scientists in the first decades of the 20th century played a major role in this transformation, notably those of the Russian biochemist Alexander I. Oparin and the British geneticist and biochemist J.B.S. Haldane. The ideas of the lesser-known American psycho-physiologist Leonard Troland also made a significant contribution to subsequent developments in origin-of-life research. Therefore, it is well worth taking a look at the professional, philosophical and ideological commitments that shaped the approaches of the three scientists to origin-of-life research. PMID:16469383

  18. The origin of grasslands in the temperate forest zone of east-central Europe: long-term legacy of climate and human impact

    NASA Astrophysics Data System (ADS)

    Kuneš, Petr; Svobodová-Svitavská, Helena; Kolář, Jan; Hajnalová, Mária; Abraham, Vojtěch; Macek, Martin; Tkáč, Peter; Szabó, Péter

    2015-05-01

    The post-glacial fate of central European grasslands has stimulated palaeoecological debates for a century. Some argued for the continuous survival of open land, while others claimed that closed forest had developed during the Middle Holocene. The reasons behind stability or changes in the proportion of open land are also unclear. We aim to reconstruct regional vegetation openness and test the effects of climate and human impact on vegetation change throughout the Holocene. We present a newly dated pollen record from north-western fringes of the Pannonian Plain, east-central Europe, and reconstruct Holocene regional vegetation development by the REVEALS model for 27 pollen-equivalent taxa. Estimated vegetation is correlated in the same area with a human activity model based on all available archaeological information and a macrophysical climate model. The palaeovegetation record indicates the continuous presence of open land throughout the Holocene. Grasslands and open woodlands were probably maintained by local arid climatic conditions during the early Holocene delaying the spread of deciduous (oak) forests. Significantly detectable human-made landscape transformation started only after 2000 BC. Our analyses suggest that Neolithic people spread into a landscape that was already open. Humans probably contributed to the spread of oak, and influenced the dynamics of hazel and hornbeam.

  19. Good Student Questions in Inquiry Learning

    ERIC Educational Resources Information Center

    Lombard, François E.; Schneider, Daniel K.

    2013-01-01

    Acquisition of scientific reasoning is one of the big challenges in education. A popular educational strategy advocated for acquiring deep knowledge is inquiry-based learning, which is driven by emerging "good questions". This study will address the question: "Which design features allow learners to refine questions while preserving…

  20. Teaching Culture: Questioning Perspectives on Our Practices

    ERIC Educational Resources Information Center

    Met, Myriam

    2010-01-01

    Despite years of training, teaching experience, reading professional literature, attending conferences, and learning from expert colleagues, when it comes to the teaching of culture, the author wishes she knew more answers to many critical questions. Her questions are framed by the basic questions that all curricula seek to answer: WHAT is the…

  1. 32 CFR 316.7 - Questions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Questions. 316.7 Section 316.7 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) PRIVACY PROGRAM DEFENSE INFORMATION SYSTEMS AGENCY PRIVACY PROGRAM § 316.7 Questions. Questions on both the substance and procedure...

  2. Doctors' questions as displays of understanding.

    PubMed

    Deppermann, Arnulf; Spranz-Fogasy, Thomas

    2011-01-01

    Based on German data from history-taking in doctor-patient interaction, the paper shows that the three basic syntactic types of questions (questions fronted by a question-word (w-questions), verb-first (V1) questions, and declarative questions) provide different opportunities for displaying understanding in medical interaction. Each syntactic question-format is predominantly used in a different stage of topical sequences in history taking: w-questions presuppose less knowledge and are thus used to open up topical sequences; declarative questions are used to check already achieved understandings and to close topical sequences. Still, the expected scope of answers to yes/no-questions and to declarative questions is less restricted than previously thought. The paper focuses in detail on the doctors' use of formulations as declarative questions, which are designed to make patients elaborate on already established topics, giving more details or accounting for a confirmation. Formulations often involve a shift to psychological aspects of the illness. Although patients confirm doctors' empathetic formulations, they, however, regularly do not align with this shift, returning to the description of symptoms and to biomedical accounts instead. The study shows how displays of understanding are responded to not only in terms of correctness, but also (and more importantly) in terms of their relevance for further action. PMID:23264976

  3. Questions That Science Teachers Find Difficult (II).

    ERIC Educational Resources Information Center

    Goodwin, Alan

    2003-01-01

    Presents some questions that science teachers find difficult. Focuses on three further questions relating to "simple" everyday situations that are normally explained in terms of the kinetic theory of matter. Identifies looking at the difference between chemical and physical changes as the most problematic question. (Author/YDS)

  4. Questions ouvertes/questions fermees: une dichotomie qui appelle une analyse critique (Open Questions/Closed Questions: A Dichotomy that Calls for a Critical Analysis).

    ERIC Educational Resources Information Center

    Vinter, Shirley; Bried, Charles

    1998-01-01

    Among the strategies used by the adult to engage the child in a linguistic interaction, those involving questioning occupy a central position. One of the parameters usually taken into account to differentiate the type of questions directed to the child is the opposition between closed (i.e., yes/no) and open-ended questions. The relevance of that…

  5. What Can We Learn from Students' Questions?

    ERIC Educational Resources Information Center

    Commeyras, Michelle

    1995-01-01

    Creating opportunities and encouraging student-centered questioning requires a special teacher-student dynamic. Students need to be empowered to ask questions. The article explores what teachers can learn from questions students ask, focusing on learning outcomes for teachers, and using a second-grade lesson on Harriet Tubman as an example. (SM)

  6. Teaching Students to Form Effective Questions

    ERIC Educational Resources Information Center

    Stafford, Tish

    2009-01-01

    The ability to question lies at the heart of human curiosity and is a necessary component of cognition. The author stresses that forming questions is essential to human thought and communication. As such, forming questions is a foundational process that cuts across curricular areas and is embedded in content standards across the nation, including…

  7. Developing Qualitative Research Questions: A Reflective Process

    ERIC Educational Resources Information Center

    Agee, Jane

    2009-01-01

    The reflective and interrogative processes required for developing effective qualitative research questions can give shape and direction to a study in ways that are often underestimated. Good research questions do not necessarily produce good research, but poorly conceived or constructed questions will likely create problems that affect all…

  8. Wh- Questions and Individuals with Intellectual Disability

    ERIC Educational Resources Information Center

    Sanders, Eric

    2012-01-01

    The purpose of this study was to investigate the comprehension of questions beginning with different wh- question words presented in two referential conditions to individuals with intellectual disability (ID). Thirty-nine school-age participants completed a battery of who, what, where, when, why, and how questions with and without a picture…

  9. Questioning and Teaching. A Manual of Practice.

    ERIC Educational Resources Information Center

    Dillon, J. T.

    Questions and questioning play a major role in both formal and informal educative processes. They are the means by which a child expresses the desire to understand the world outside and they subsequently become the means by which a teacher assesses whether or not a child has satisfactorily assimilated something. This book considers questions from…

  10. Delivery of QTIiv2 Question Types

    ERIC Educational Resources Information Center

    Wills, Gary B.; Davis, Hugh C.; Gilbert, Lester; Hare, Jonathon; Howard, Yvonne; Jeyes, Steve; Millard, David; Sherratt, Robert

    2009-01-01

    The IMS Question and Test Interoperability (QTI) standard identifies 16 different question types which may be used in online assessment. While some partial implementations exist, the R2Q2 project has developed a complete solution that renders and responds to all 16 question types as specified. In addition, care has been taken in the R2Q2 project…

  11. Better Questions and Answers Equal Success.

    ERIC Educational Resources Information Center

    Swicegood, Philip R.; Parsons, James L.

    1989-01-01

    Students with learning disabilities and behavior problems need instruction designed to increase active thinking and questioning skills. Described methods for teaching these skills include T. Raphael's question-answer relationships, A. Hahn's questioning strategy, reciprocal teaching, and the "ReQuest" procedure. Practice activities for student…

  12. Questions and Answers About Nuclear Power Plants.

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC.

    This pamphlet is designed to answer many of the questions that have arisen about nuclear power plants and the environment. It is organized into a question and answer format, with the questions taken from those most often asked by the public. Topics include regulation of nuclear power sources, potential dangers to people's health, whether nuclear…

  13. How to Make Your Questions Essential

    ERIC Educational Resources Information Center

    Wiggins, Grant; Wilbur, Denise

    2015-01-01

    Good essential questions rarely emerge in the first draft. Common first-draft questions typically are convergent low-level questions designed to support content acquisition. They either point toward the one official "right" answer, or they elicit mere lists and thus no further inquiry. So how can teachers ensure that subsequent drafts…

  14. The Meaning of Student Inquiry Questions: A Teacher's Beliefs and Responses.

    ERIC Educational Resources Information Center

    Rop, Charles J.

    2002-01-01

    Explores an American high school chemistry teacher's perspective on the meaning of student questions that originate from curiosity and engagement with the subject matter. Uses ethnographic analysis of a teacher's reflective processes and decision making approach and suggests that questions hold contradictory meaning as powerful, conflicting…

  15. Effects of Re-Using a Conceptual Examination Question in Physics

    ERIC Educational Resources Information Center

    Sharma, Manjula D.; Sefton, Ian M.; Cole, Martyn; Whymark, Aaron; Millar, Rosemary M.; Smith, Andrew

    2005-01-01

    We report on a study of what happened when we recycled a conceptual examination question in a first-year university physics course. The question, which was used for three consecutive years, asked about an astronaut's experience of weighing in an orbiting space-craft. The original intention was to use a phenomenographic approach to look for…

  16. Asking Scientists: A Decade of Questions Analyzed by Age, Gender, and Country

    ERIC Educational Resources Information Center

    Baram-Tsabari, Ayelet; Sethi, Ricky J.; Bry, Lynn; Yarden, Anat

    2009-01-01

    Nearly 79,000 questions sent to an Internet-based Ask-A-Scientist site during the last decade were analyzed according to the surfer's age, gender, country of origin, and the year the question was sent. The sample demonstrated a surprising dominance of female contributions among K-12 students (although this dominance did not carry over to the full…

  17. Medical Marijuana: More Questions than Answers

    PubMed Central

    Hill, Kevin P.

    2014-01-01

    With 23 states and the District of Columbia having enacted medical marijuana laws as of August 2014, it is important that psychiatrists be able to address questions about medical marijuana from patients, families, and other health care professionals. The author discusses the limited medical literature on synthetic cannabinoids and medical marijuana. The synthetic cannabinoids dronabinol and nabilone are approved by the United States Food and Drug Administration for nausea and vomiting associated with cancer chemotherapy and appetite stimulation in patients with wasting diseases such as acquired immunodeficiency syndrome (AIDS). Results of clinical trials of these agents for other conditions have varied widely thus far. In addition, few data are available on the use of the marijuana plant as a medical treatment. The author concludes that there is a clear need for additional research on possible medical uses of cannabinoids. He notes that discussions with prospective medical marijuana patients should emphasize the importance of communication among all parties due to the possible side effects of treatment with marijuana and its potential to interact with other medications the patient may be taking. Facilitating a thorough substance abuse consultation is one of most positive ways that psychiatrists, especially addiction psychiatrists, can make an impact as medical marijuana becomes increasingly common. A careful review of the prospective medical marijuana user's substance use history, co-occurring medical and psychiatric conditions, family history, and psychosocial stressors is essential in evaluating the potential risks of medical marijuana for these patients. The author concludes that psychiatrists can have a significant impact by increasing the likelihood that medical marijuana will be used in a safe and responsible way. PMID:25226202

  18. Medical marijuana: more questions than answers.

    PubMed

    Hill, Kevin P

    2014-09-01

    With 23 states and the District of Columbia having enacted medical marijuana laws as of August 2014, it is important that psychiatrists be able to address questions about medical marijuana from patients, families, and other health care professionals. The author discusses the medical literature on synthetic cannabinoids and medical marijuana. The synthetic cannabinoids dronabinol and nabilone are approved by the United States Food and Drug Administration for nausea and vomiting associated with cancer chemotherapy and appetite stimulation in patients with wasting diseases such as acquired immunodeficiency syndrome (AIDS). Results of clinical trials of these agents for other conditions have varied widely thus far. In addition, few data are available on the use of the marijuana plant as a medical treatment. The author concludes that there is a clear need for additional research on possible medical uses of cannabinoids. He notes that discussions with prospective medical marijuana patients should emphasize the importance of communication among all parties due to the possible side effects of treatment with marijuana and its potential to interact with other medications the patient may be taking. Facilitating a thorough substance abuse consultation is one of most positive ways that psychiatrists, especially addiction psychiatrists, can make an impact as medical marijuana becomes increasingly common. A careful review of the prospective medical marijuana user's substance use history, co-occurring medical and psychiatric conditions, family history, and psychosocial stressors is essential in evaluating the potential risks of medical marijuana for these patients. The author concludes that psychiatrists can have a significant impact by increasing the likelihood that medical marijuana will be used in a safe and responsible way. PMID:25226202

  19. Medical marijuana: more questions than answers.

    PubMed

    Hill, Kevin P

    2014-09-01

    With 23 states and the District of Columbia having enacted medical marijuana laws as of August 2014, it is important that psychiatrists be able to address questions about medical marijuana from patients, families, and other health care professionals. The author discusses the medical literature on synthetic cannabinoids and medical marijuana. The synthetic cannabinoids dronabinol and nabilone are approved by the United States Food and Drug Administration for nausea and vomiting associated with cancer chemotherapy and appetite stimulation in patients with wasting diseases such as acquired immunodeficiency syndrome (AIDS). Results of clinical trials of these agents for other conditions have varied widely thus far. In addition, few data are available on the use of the marijuana plant as a medical treatment. The author concludes that there is a clear need for additional research on possible medical uses of cannabinoids. He notes that discussions with prospective medical marijuana patients should emphasize the importance of communication among all parties due to the possible side effects of treatment with marijuana and its potential to interact with other medications the patient may be taking. Facilitating a thorough substance abuse consultation is one of most positive ways that psychiatrists, especially addiction psychiatrists, can make an impact as medical marijuana becomes increasingly common. A careful review of the prospective medical marijuana user's substance use history, co-occurring medical and psychiatric conditions, family history, and psychosocial stressors is essential in evaluating the potential risks of medical marijuana for these patients. The author concludes that psychiatrists can have a significant impact by increasing the likelihood that medical marijuana will be used in a safe and responsible way.

  20. Planetary protection - some legal questions

    NASA Astrophysics Data System (ADS)

    Fasan, E.

    2004-01-01

    When we legally investigate the topic of Planetary Protection, we have to realise that there are primarily two very distinct parts of our juridical work: We have to study lexlata, theexistingapplicableLaw, especially Space Law, and also lexferenda, whatshouldbethe law . With this in mind, we have to deliberate the legal meaning of the notions "Planetary", and "Protection". About " Planetary": Our own Earth is our most important planet. At present only here do exist human beings, who are sensu strictu the only legal subjects. We make the law, we have to apply it, and we are to be protected as well as bound by it. But what is further meant by "Planetary"? Is it planets in an astronomical sense only, the nine planets which revolve around our fixed star, namely the sun, or is it also satellites, moving around most of these planets, as our own Moon circles Earth. "The Moon and other Celestial Bodies (C.B.)" are subject to Space Law, especially to International Treaties, Agreements, Resolutions of the UN, etc. I propose that they and not only the planets in an strictly astronomical sense are to be protected. But I do not think that the said notion also comprises asteroids, comets, meteorites, etc. although they too belong to our solar system. Our investigation comes to the result that such bodies have a different (lesser) legal quality. Also we have to ask Protectionfrom what ? From: Natural bodies - Meteorites, NEO Asteroids, Comets which could hit Earth or C.B.Artificial Objects: Space Debris threatening especially Earth and near Earth orbits.Terrestrial Life - no infection of other celestial bodies. Alien life forms which could bring about "harmful contamination" of Earth and the life, above all human life, there, etc. Here, astrobiological questions have to be discussed. Special realms on C.B. which should be protected from electronic "noise" such as craters SAHA or Deadalus on the Moon, also taking into account the "Common Heritage" Principle. Then, we have to