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Sample records for 30s 31cl deduced

  1. Experimental Investigation of the Stellar Reaction 30S(p,γ)31Cl via Coulomb Dissociation

    NASA Astrophysics Data System (ADS)

    Togano, Y.; Motobayashi, T.; Aoi, N.; Baba, H.; Bishop, S.; Cai, X.; Doornenbal, P.; Fang, D.; Furukawa, T.; Ieki, K.; Iwasa, N.; Kawabata, T.; Kanno, S.; Kobayashi, N.; Kondo, Y.; Kuboki, T.; Kume, N.; Kurita, K.; Kurokawa, M.; Ma, Y. G.; Matsuo, Y.; Murakami, H.; Matsushita, M.; Nakamura, T.; Okada, K.; Ota, S.; Satou, Y.; Shimoura, S.; Shioda, R.; Tanaka, K. N.; Takeuchi, S.; Tian, W.; Wang, H.; Wang, J.; Yamada, K.; Yamada, Y.; Yoneda, K.

    2011-09-01

    Coulomb dissociation of the proton-rich nucleus 31Cl was studied experimentally using a 31Cl beam at 58 MeV/nucleon with a lead target. The relative energy spectrum of 30S+p system was obtained from the measured momentum vectors of the reaction products detected in coincidence by the invariant mass method. The first excited state in 31Cl was observed which is relevant to the resonant capture in the stellar 30S(p,γ)31Cl reaction. Discussion for another observed state is also given.

  2. Mass of astrophysically relevant 31Cl and the breakdown of the isobaric multiplet mass equation

    NASA Astrophysics Data System (ADS)

    Kankainen, A.; Canete, L.; Eronen, T.; Hakala, J.; Jokinen, A.; Koponen, J.; Moore, I. D.; Nesterenko, D.; Reinikainen, J.; Rinta-Antila, S.; Voss, A.; ńystö, J.

    2016-04-01

    The mass of 31Cl has been measured with the JYFLTRAP double-Penning-trap mass spectrometer at the Ion Guide Isotope Separator On-Line (IGISOL) facility. The determined mass-excess value, -7034.7 (34 ) keV, is 15 times more precise than in the Atomic Mass Evaluation 2012. The quadratic form of the isobaric multiplet mass equation for the T =3 /2 quartet at A =31 fails (χn2=11.6 ) and a nonzero cubic term, d =-3.5 (11 ) keV, is obtained when the new mass value is adopted. 31Cl has been found to be less proton-bound, with a proton separation energy of Sp=264.6 (34 ) keV. Energies for the excited states in 31Cl and the photodisintegration rate on 31Cl have been determined with significantly improved precision by using the new Sp value. The improved photodisintegration rate helps to constrain astrophysical conditions where 30S can act as a waiting point in the rapid proton capture process in type-I x-ray bursts.

  3. A dye-sensitized visible light photocatalyst-Bi24O31Cl10

    PubMed Central

    Wang, Liang; Shang, Jun; Hao, Weichang; Jiang, Shiqi; Huang, Shiheng; Wang, Tianmin; Sun, Ziqi; Du, Yi; Dou, Shixue; Xie, Tengfeng; Wang, Dejun; Wang, Jiaou

    2014-01-01

    The p-block semiconductors are regarded as a new family of visible-light photocatalysts because of their dispersive and anisotropic band structures as well as high chemical stability. The bismuth oxide halides belong to this family and have band structures and dispersion relations that can be engineered by modulating the stoichiometry of the halogen elements. Herein, we have developed a new visible-light photocatalyst Bi24O31Cl10 by band engineering, which shows high dye-sensitized photocatalytic activity. Density functional theory calculations reveal that the p-block elements determine the nature of the dispersive electronic structures and narrow band gap in Bi24O31Cl10. Bi24O31Cl10 exhibits excellent visible-light photocatalytic activity towards the degradation of Rhodamine B, which is promoted by dye sensitization due to compatible energy levels and high electronic mobility. In addition, Bi24O31Cl10 is also a suitable photoanode material for dye-sensitized solar cells and shows power conversion efficiency of 1.5%. PMID:25488704

  4. 31Cl beta decay and the 30P31S reaction rate in nova nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Bennett, Michael; Wrede, C.; Brown, B. A.; Liddick, S. N.; Pérez-Loureiro, D.; NSCL e12028 Collaboration

    2016-03-01

    The 30P31S reaction rate is critical for modeling the final isotopic abundances of ONe nova nucleosynthesis, identifying the origin of presolar nova grains, and calibrating proposed nova thermometers. Unfortunately, this rate is essentially experimentally unconstrained because the strengths of key 31S proton capture resonances are not known, due to uncertainties in their spins and parities. Using a 31Cl beam produced at the National Superconducting Cyclotron Laboratory, we have populated several 31S states for study via beta decay and devised a new decay scheme which includes updated beta feedings and gamma branchings as well as multiple states previously unobserved in 31Cl beta decay. Results of this study, including the unambiguous identification due to isospin mixing of a new l = 0 , Jπ = 3 /2+ 31S resonance directly in the middle of the Gamow Window, will be presented, and significance to the evaluation of the 30P31S reaction rate will be discussed. Work supported by U.S. Natl. Sci. Foundation (Grants No. PHY-1102511, PHY-1404442, PHY-1419765, and PHY-1431052); U.S. Dept. of Energy, Natl. Nucl. Security Administration (Award No. DE-NA0000979); Nat. Sci. and Eng. Research Council of Canada.

  5. Constructing Bi24O31Cl10/BiOCl heterojunction via a simple thermal annealing route for achieving enhanced photocatalytic activity and selectivity

    PubMed Central

    Liu, Xiaoyan; Su, Yiguo; Zhao, Qihang; Du, Chunfang; Liu, Zhiliang

    2016-01-01

    This work reports on the construction of a Bi24O31Cl10/BiOCl heterojunction via a simple thermal annealing method. The X-ray diffraction (XRD) results indicated that the phase transformation from BiOCl to Bi24O31Cl10 could be realized during the thermal annealing process. The high-resolution transmission electron microscopy (HRTEM) images, X-ray photoelectron spectroscopy (XPS) binding energy shifts, Raman spectra and Fouier transform infrared spectroscopy (FT-IR) spectra confirmed the formation of the Bi24O31Cl10/BiOCl heterojunction. The obtained Bi24O31Cl10/BiOCl photocatalyst showed excellent conversion efficiency and selectivity toward photocatalytic conversion of benzyl alcohol to benzaldehyde under visible light irradiation. The radical scavengers and electron spin resonance (ESR) results suggested that the photogenerated holes were the dominant reactive species responsible for the photocatalytic oxidation of benzyl alcohol and superoxide radicals were not involved in the photocatalytic process. The in-situ generation of Bi24O31Cl10/BiOCl heterojunction may own superior interfacial contact than the two-step synthesized heterojunctions, which promotes the transfer of photogenerated charge carriers and is favorable for excellent photocatalytic activities. PMID:27340032

  6. Constructing Bi24O31Cl10/BiOCl heterojunction via a simple thermal annealing route for achieving enhanced photocatalytic activity and selectivity

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyan; Su, Yiguo; Zhao, Qihang; Du, Chunfang; Liu, Zhiliang

    2016-06-01

    This work reports on the construction of a Bi24O31Cl10/BiOCl heterojunction via a simple thermal annealing method. The X-ray diffraction (XRD) results indicated that the phase transformation from BiOCl to Bi24O31Cl10 could be realized during the thermal annealing process. The high-resolution transmission electron microscopy (HRTEM) images, X-ray photoelectron spectroscopy (XPS) binding energy shifts, Raman spectra and Fouier transform infrared spectroscopy (FT-IR) spectra confirmed the formation of the Bi24O31Cl10/BiOCl heterojunction. The obtained Bi24O31Cl10/BiOCl photocatalyst showed excellent conversion efficiency and selectivity toward photocatalytic conversion of benzyl alcohol to benzaldehyde under visible light irradiation. The radical scavengers and electron spin resonance (ESR) results suggested that the photogenerated holes were the dominant reactive species responsible for the photocatalytic oxidation of benzyl alcohol and superoxide radicals were not involved in the photocatalytic process. The in-situ generation of Bi24O31Cl10/BiOCl heterojunction may own superior interfacial contact than the two-step synthesized heterojunctions, which promotes the transfer of photogenerated charge carriers and is favorable for excellent photocatalytic activities.

  7. Constructing Bi24O31Cl10/BiOCl heterojunction via a simple thermal annealing route for achieving enhanced photocatalytic activity and selectivity.

    PubMed

    Liu, Xiaoyan; Su, Yiguo; Zhao, Qihang; Du, Chunfang; Liu, Zhiliang

    2016-01-01

    This work reports on the construction of a Bi24O31Cl10/BiOCl heterojunction via a simple thermal annealing method. The X-ray diffraction (XRD) results indicated that the phase transformation from BiOCl to Bi24O31Cl10 could be realized during the thermal annealing process. The high-resolution transmission electron microscopy (HRTEM) images, X-ray photoelectron spectroscopy (XPS) binding energy shifts, Raman spectra and Fouier transform infrared spectroscopy (FT-IR) spectra confirmed the formation of the Bi24O31Cl10/BiOCl heterojunction. The obtained Bi24O31Cl10/BiOCl photocatalyst showed excellent conversion efficiency and selectivity toward photocatalytic conversion of benzyl alcohol to benzaldehyde under visible light irradiation. The radical scavengers and electron spin resonance (ESR) results suggested that the photogenerated holes were the dominant reactive species responsible for the photocatalytic oxidation of benzyl alcohol and superoxide radicals were not involved in the photocatalytic process. The in-situ generation of Bi24O31Cl10/BiOCl heterojunction may own superior interfacial contact than the two-step synthesized heterojunctions, which promotes the transfer of photogenerated charge carriers and is favorable for excellent photocatalytic activities. PMID:27340032

  8. Study of excited states of {sup 31}S through beta-decay of {sup 31}Cl for nucleosynthesis in ONe novae

    SciTech Connect

    Saastamoinen, A.; Jokinen, A.; Aeystoe, J.; Trache, L.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B.; Simmons, E.; Tabacaru, G.; Tribble, R. E.; Banu, A.; Bentley, M. A.; Davinson, T.; Woods, P. J.

    2011-11-30

    We have produced an intense and pure beam of {sup 31}Cl with the MARS Separator at the Texas A and M University and studied {beta}-decay of {sup 31}Cl by implanting the beam into a novel detector setup, capable of measuring {beta}-delayed protons and {gamma}-rays simultaneously. From our data, we have established decay scheme of {sup 31}Cl, found resonance energies with 1 keV precision, have measured its half-life with under 1% accuracy, found its Isobar Analog State decay and by using the IMME obtained an improved mass excess for its ground state. In this contribution, a description of the used method along with selected preliminary experimental results are given and their relevance for novae nucleosynthesis discussed.

  9. Beta-decay of 31Cl: an indirect probe of the 30P(p,γ)31S reaction. Present status and future perspectives

    NASA Astrophysics Data System (ADS)

    Saastamoinen, Antti; Kankainen, Anu; Trache, Livius

    2016-08-01

    β-decay of 31Cl can be used as a selective tool for studying astrophysically relevant states in 31S. In this article we review the present status of the decay data. The implications for the 30P(p,γ)31S reaction rate at novae temperatures, and future experimental ideas are discussed.

  10. {sup 30}S Beam Development and X-ray Bursts

    SciTech Connect

    Kahl, D.; Kubono, S.; Binh, D. N.; Hashimoto, T.; Hayakawa, S.; Kurihara, Y.; Ohshiro, Y.; Yamaguchi, H.; Chen, A. A.; Chen, J.; Setoodeh nia, K.; Kaji, D.; Nishimura, S.; Kim, A.; Lee, N. H.; Wakabayashi, Y.

    2010-03-01

    Over the past three years, we have worked on developing a well-characterized {sup 30}S radioactive beam to be used in a future experiment aiming to directly measure to extrapolate the {sup 30}S(alpha,p) stellar reaction rate within the Gamow window of Type I X-ray bursts. The importance of the {sup 30}S(alpha,p) reaction to X-ray bursts is discussed. Given the astrophysical motivation, the successful results of and challenges involved in the production of a low-energy {sup 30}S beam are detailed. Finally, an overview of our future plans regarding this on-going project are presented.

  11. {sup 30}S({alpha}, p) in X-Ray Bursts at CRIB

    SciTech Connect

    Kahl, D.; Kubono, S.; Binh, D. N.; Hashimoto, T.; Hayakawa, S.; Kurihara, Y.; Ohshiro, Y.; Yamaguchi, H.; Chen, A. A.; Chen, J.; Setoodeh nia, K.; Kaji, D.; Nishimura, S.; Kim, A.; Lee, N. H.; Wakabayashi, Y.

    2010-08-12

    Over the past three years, we have worked on developing a well-characterized {sup 30}S radioactive beam to be used in a future experiment aiming to directly measure the {sup 30}S({alpha}, p) stellar reaction rate within the Gamow window of Type I X-ray bursts.

  12. Finite pure integer programming algorithms employing only hyperspherically deduced cuts

    NASA Technical Reports Server (NTRS)

    Young, R. D.

    1971-01-01

    Three algorithms are developed that may be based exclusively on hyperspherically deduced cuts. The algorithms only apply, therefore, to problems structured so that these cuts are valid. The algorithms are shown to be finite.

  13. The Cryo-EM Structure of a Complete 30S Translation Initiation Complex from Escherichia coli

    PubMed Central

    Julián, Patricia; Milon, Pohl; Agirrezabala, Xabier; Lasso, Gorka; Gil, David; Rodnina, Marina V.; Valle, Mikel

    2011-01-01

    Formation of the 30S initiation complex (30S IC) is an important checkpoint in regulation of gene expression. The selection of mRNA, correct start codon, and the initiator fMet-tRNAfMet requires the presence of three initiation factors (IF1, IF2, IF3) of which IF3 and IF1 control the fidelity of the process, while IF2 recruits fMet-tRNAfMet. Here we present a cryo-EM reconstruction of the complete 30S IC, containing mRNA, fMet-tRNAfMet, IF1, IF2, and IF3. In the 30S IC, IF2 contacts IF1, the 30S subunit shoulder, and the CCA end of fMet-tRNAfMet, which occupies a novel P/I position (P/I1). The N-terminal domain of IF3 contacts the tRNA, whereas the C-terminal domain is bound to the platform of the 30S subunit. Binding of initiation factors and fMet-tRNAfMet induces a rotation of the head relative to the body of the 30S subunit, which is likely to prevail through 50S subunit joining until GTP hydrolysis and dissociation of IF2 take place. The structure provides insights into the mechanism of mRNA selection during translation initiation. PMID:21750663

  14. The Cryo-EM structure of a complete 30S translation initiation complex from Escherichia coli.

    PubMed

    Julián, Patricia; Milon, Pohl; Agirrezabala, Xabier; Lasso, Gorka; Gil, David; Rodnina, Marina V; Valle, Mikel

    2011-07-01

    Formation of the 30S initiation complex (30S IC) is an important checkpoint in regulation of gene expression. The selection of mRNA, correct start codon, and the initiator fMet-tRNA(fMet) requires the presence of three initiation factors (IF1, IF2, IF3) of which IF3 and IF1 control the fidelity of the process, while IF2 recruits fMet-tRNA(fMet). Here we present a cryo-EM reconstruction of the complete 30S IC, containing mRNA, fMet-tRNA(fMet), IF1, IF2, and IF3. In the 30S IC, IF2 contacts IF1, the 30S subunit shoulder, and the CCA end of fMet-tRNA(fMet), which occupies a novel P/I position (P/I1). The N-terminal domain of IF3 contacts the tRNA, whereas the C-terminal domain is bound to the platform of the 30S subunit. Binding of initiation factors and fMet-tRNA(fMet) induces a rotation of the head relative to the body of the 30S subunit, which is likely to prevail through 50S subunit joining until GTP hydrolysis and dissociation of IF2 take place. The structure provides insights into the mechanism of mRNA selection during translation initiation. PMID:21750663

  15. Deducing Reaction Mechanism: A Guide for Students, Researchers, and Instructors

    ERIC Educational Resources Information Center

    Meek, Simon J.; Pitman, Catherine L.; Miller, Alexander J. M.

    2016-01-01

    An introductory guide to deducing the mechanism of chemical reactions is presented. Following a typical workflow for probing reaction mechanism, the guide introduces a wide range of kinetic and mechanistic tools. In addition to serving as a broad introduction to mechanistic analysis for students and researchers, the guide has also been used by…

  16. Goniometer-based femtosecond X-ray diffraction of mutant 30S ribosomal subunit crystals

    SciTech Connect

    Dao, E. Han; Sierra, Raymond G.; Laksmono, Hartawan; Lemke, Henrik T.; Alonso-Mori, Roberto; Coey, Aaron; Larsen, Kevin; Baxter, Elizabeth L.; Cohen, Aina E.; Soltis, S. Michael; DeMirci, Hasan

    2015-04-30

    In this work, we collected radiation-damage-free data from a set of cryo-cooled crystals for a novel 30S ribosomal subunit mutant using goniometer-based femtosecond crystallography. Crystal quality assessment for these samples was conducted at the X-ray Pump Probe end-station of the Linac Coherent Light Source (LCLS) using recently introduced goniometer-based instrumentation. These 30S subunit crystals were genetically engineered to omit a 26-residue protein, Thx, which is present in the wild-type Thermus thermophilus 30S ribosomal subunit. We are primarily interested in elucidating the contribution of this ribosomal protein to the overall 30S subunit structure. To assess the viability of this study, femtosecond X-ray diffraction patterns from these crystals were recorded at the LCLS during a protein crystal screening beam time. During our data collection, we successfully observed diffraction from these difficult-to-grow 30S ribosomal subunit crystals. Most of our crystals were found to diffract to low resolution, while one crystal diffracted to 3.2 Å resolution. These data suggest the feasibility of pursuing high-resolution data collection as well as the need to improve sample preparation and handling in order to collect a complete radiation-damage-free data set using an X-ray Free Electron Laser.

  17. Experimental investigation of the 30S(α, p) thermonuclear reaction in x-ray bursts

    NASA Astrophysics Data System (ADS)

    Kahl, D.; Chen, A. A.; Kubono, S.; Yamaguchi, H.; Binh, D. N.; Chen, J.; Cherubini, S.; Duy, N. N.; Hashimoto, T.; Hayakawa, S.; Iwasa, N.; Jung, H. S.; Kato, S.; Kwon, Y. K.; Nishimura, S.; Ota, S.; Setoodehnia, K.; Teranishi, T.; Tokieda, H.; Yamada, T.; Yun, C. C.; Zhang, L. Y.

    2016-02-01

    We performed the first measurement of 30S+α resonant elastic scattering to experimentally examine the 30S(α, p) stellar reaction rate in type I x-ray bursts. These bursts are the most frequent thermonuclear explosions in the galaxy, resulting from thermonuclear runaway on the surface of accreting neutron star binaries. The 30S(α, p) reaction plays a critical role in burst models, yet very little is known about the compound nucleus 34Ar at these energies nor the reaction rate itself. We performed a measurement of alpha elastic scattering with a radioactive beam of 30S to experimentally probe the entrance channel. Utilizing a gaseous active target system and silicon detector array, we extracted the excitation function from 1.8 to 5.5 MeV near 160° in the center-of-mass frame. The experimental data were analyzed with an R-Matrix calculation, and we discovered several new resonances and extracted their quantum properties (resonance energy, width, spin, and parity). Finally, we calculated the narrow resonant thermonuclear reaction rate of 30S(α, p) for these new resonances.

  18. Goniometer-based femtosecond X-ray diffraction of mutant 30S ribosomal subunit crystals.

    PubMed

    Dao, E Han; Sierra, Raymond G; Laksmono, Hartawan; Lemke, Henrik T; Alonso-Mori, Roberto; Coey, Aaron; Larsen, Kevin; Baxter, Elizabeth L; Cohen, Aina E; Soltis, S Michael; DeMirci, Hasan

    2015-07-01

    In this work, we collected radiation-damage-free data from a set of cryo-cooled crystals for a novel 30S ribosomal subunit mutant using goniometer-based femtosecond crystallography. Crystal quality assessment for these samples was conducted at the X-ray Pump Probe end-station of the Linac Coherent Light Source (LCLS) using recently introduced goniometer-based instrumentation. These 30S subunit crystals were genetically engineered to omit a 26-residue protein, Thx, which is present in the wild-type Thermus thermophilus 30S ribosomal subunit. We are primarily interested in elucidating the contribution of this ribosomal protein to the overall 30S subunit structure. To assess the viability of this study, femtosecond X-ray diffraction patterns from these crystals were recorded at the LCLS during a protein crystal screening beam time. During our data collection, we successfully observed diffraction from these difficult-to-grow 30S ribosomal subunit crystals. Most of our crystals were found to diffract to low resolution, while one crystal diffracted to 3.2 Å resolution. These data suggest the feasibility of pursuing high-resolution data collection as well as the need to improve sample preparation and handling in order to collect a complete radiation-damage-free data set using an X-ray Free Electron Laser. PMID:26798805

  19. Goniometer-based femtosecond X-ray diffraction of mutant 30S ribosomal subunit crystals

    DOE PAGESBeta

    Dao, E. Han; Sierra, Raymond G.; Laksmono, Hartawan; Lemke, Henrik T.; Alonso-Mori, Roberto; Coey, Aaron; Larsen, Kevin; Baxter, Elizabeth L.; Cohen, Aina E.; Soltis, S. Michael; et al

    2015-04-30

    In this work, we collected radiation-damage-free data from a set of cryo-cooled crystals for a novel 30S ribosomal subunit mutant using goniometer-based femtosecond crystallography. Crystal quality assessment for these samples was conducted at the X-ray Pump Probe end-station of the Linac Coherent Light Source (LCLS) using recently introduced goniometer-based instrumentation. These 30S subunit crystals were genetically engineered to omit a 26-residue protein, Thx, which is present in the wild-type Thermus thermophilus 30S ribosomal subunit. We are primarily interested in elucidating the contribution of this ribosomal protein to the overall 30S subunit structure. To assess the viability of this study, femtosecondmore » X-ray diffraction patterns from these crystals were recorded at the LCLS during a protein crystal screening beam time. During our data collection, we successfully observed diffraction from these difficult-to-grow 30S ribosomal subunit crystals. Most of our crystals were found to diffract to low resolution, while one crystal diffracted to 3.2 Å resolution. These data suggest the feasibility of pursuing high-resolution data collection as well as the need to improve sample preparation and handling in order to collect a complete radiation-damage-free data set using an X-ray Free Electron Laser.« less

  20. First measurement of the 33Cl(p,α)30S reaction

    NASA Astrophysics Data System (ADS)

    Deibel, C. M.; Rehm, K. E.; Figueira, J. M.; Greene, J. P.; Jiang, C. L.; Kay, B. P.; Lee, H. Y.; Lighthall, J. C.; Marley, S. T.; Pardo, R. C.; Patel, N.; Paul, M.; Ugalde, C.; Woodard, A.; Wuosmaa, A. H.; Zinkann, G.

    2011-10-01

    The 30S(α,p)33Cl reaction may have a significant impact on final elemental abundances and energy output of type I X-ray bursts, as well as influencing observables such as double-peaked luminosity profiles, because it could bypass the 30S waiting point. This reaction has been studied experimentally for the first time in inverse kinematics via the time-inverse reaction 1H(33Cl,30S)α with a 33Cl radioactive ion beam produced at the Argonne Tandem Linac Accelerator System facility by the “in-flight” technique. This reaction was studied at three different beam energies. The experimental method used and the resulting data are discussed.

  1. General Constraints on Cross Sections Deduced from Surrogate Reactions

    SciTech Connect

    Younes, W

    2003-08-14

    Cross sections that cannot be measured in the laboratory, e.g. because the target lifetime is too short, can be inferred indirectly from a different reaction forming the same compound system, but with a more accessible beam/target combination (the ''surrogate-reaction'' technique). The reactions share the same compound system and a common decay mechanism, but they involve different formation processes. Therefore, an implicit constraint is imposed on the inferred cross section deduced from the measured surrogate-reaction data, through the common decay mechanism. In this paper, the mathematical consequences of this implicit constraint are investigated. General formulas are derived from upper and lower bounds on the inferred cross section, estimated from surrogate data in a procedure which does not require any modeling of the common decay process. As an example, the formulas developed here are applied to the case of the {sup 235}U(n,f) cross section, deduced from {sup 234}U(t,pf) surrogate data. The calculated bounds are not very tight in this particular case. However, by introducing a few qualitative assumptions about the physics of the fission process, meaningful bounds on the deduced cross section are obtained. Upper and lower limits for the cross-section ratio of the (n,f) reaction on the {sup 235}U isomer at E{sub x} = 77 eV relative to the (n,f) reaction on the ground state are also calculated. The generalization of this technique to other surrogate reactions is discussed.

  2. Studies on dissociation and reconstitution of nuclear 30-S ribonucleoprotein particles containing pre-mRNA.

    PubMed

    Kulguskin, V V; Krichevskaya, A A; Lukanidin, E M; Georgiev, G P

    1980-10-17

    Treatment of nuclear 30-S ribonucleoprotein (RNP) particles containing pre-mRNA (precursor of mRNA) with 2 M NaCl leads to dissociation of RNA and protein. The protein component is present either as an aggregate with a sedimentation coefficient close to 30 S (a free informofer) or as a slowly sedimenting material (monomers or oligomers of informatin). Most of the informofers and slowly sedimenting material are in the equilibrium state. Iodination or aging of the 30-S particles stabilizes informofers. Lowering of NaCl concentration in the mixture of RNA with informofers or informatin subunits leads to reconstitution of RNP particles. In both cases, the particles formed have a sedimentation coefficient of about 30 S and a buoyant density equal to 1.4-1.41 g/cm3 but their response to pancreatic RNAase (EC 3.1.27.5) and high salt treatment is very different. Both the particles reconstituted from RNA and informofers and the original particles are very sensitive to pancreatic RNAase and after high salt treatment free informofers are formed. In contrast, the RNA of the particles reconstituted from slowly sedimenting material is much more protected against pancreatic RNAase action. These particles are also rather stable to high salt treatment. Thus, only if a protein in the form of an informofer aggregate is used, faithful reconstitution takes place. The data obtained are discussed in terms of the structure of the nuclear ribonucleoprotein particles containing precursor of messenger RNA. PMID:7437433

  3. Effect of intermittent hypoxic training on 20 km time trial and 30 s anaerobic performance.

    PubMed

    Hamlin, M J; Marshall, H C; Hellemans, J; Ainslie, P N; Anglem, N

    2010-08-01

    This study aimed to verify whether the "live low, train high" approach is beneficial for endurance and/or anaerobic cycling performance. Sixteen well-trained athletes completed 90 min of endurance training (60-70% of heart rate reserve), followed by two 30-s all-out sprints (Wingate test), daily, for 10 consecutive days. Nine subjects [intermittent hypoxic training (IHT) group] trained with an F(I)O(2) set to produce arterial oxygen saturations of approximately 88-82%, while seven subjects (placebo group) trained while breathing a normal gas mixture (F(I)O(2)=0.21). Four performance tests were conducted at sea level including a familiarization and baseline trial, followed by repeat trials at 2 and 9 days post-intervention. Relative to the placebo group, the mean power during the 30-s Wingate test increased by 3.0% (95% confidence limits, CL +/- 3.5%) 2 days, and 1.7% (+/- 3.8%) 9 days post-IHT. Changes in other performance variables (30 s peak power, 20 km mean power and 20 km oxygen cost) were unclear. During the time trial, the IHT participants' blood lactate concentration, respiratory exchange ratio, and SpO(2), relative to the placebo group, was substantially increased at 2 days post-intervention. The addition of IHT to the normal training program of well-trained athletes produced worthwhile gains in 30 s sprint performance possibly through enhanced glycolysis. PMID:19793215

  4. Precipitation processes as deduced by combining Doppler radar and disdrometer

    NASA Astrophysics Data System (ADS)

    Thomson, Alan Douglas

    Precipitation processes are investigated in stratiform and convective weather systems by combining Doppler radar and disdrometer measurements. Vertical scans are designed to measure the standard radar data fields and the power spectrum of the vertical Doppler velocities with high spatial and temporal resolution. A new method, based on iterative application of a disdrometer-determined Z-R relation, is developed to estimate vertical winds from the vertical scan data. Using this method, radar-based raindrop size spectra calculated near the surface in light stratiform rain compare well with simultaneous measurements from a collocated disdrometer. A full raindrop size spectrum profile is deduced for a specific steady state case. It is found that the spectrum does not vary with height, suggesting that the spectral shape is mainly controlled by the ice particles occurring above the 0oC level. Vertical scan data are also combined with volume scan data obtained by the Atmospheric Environment Service King City radar to examine the precipitation structure of a hail producing region within a severe squall line. The vertical scan shows a large variation in precipitation structure and also reveals important storm features which, in this case, are not detected by the conventional volume scans, such as a weak echo vault, a downdraught outflow, and streaks of very high downward velocity corresponding to separate hail trajectories. The power spectra were used to identify and locate hailstones, to deduce the growth of descending hailstones, and to qualitatively examine properties of raindrop size spectra. A conceptual model of hail formation is proposed by comparing the deduced storm structure and precipitation processes with the analyses of two somewhat similar storms documented in the literature.

  5. Visualizing ribosome biogenesis: parallel assembly pathways for the 30S subunit.

    PubMed

    Mulder, Anke M; Yoshioka, Craig; Beck, Andrea H; Bunner, Anne E; Milligan, Ronald A; Potter, Clinton S; Carragher, Bridget; Williamson, James R

    2010-10-29

    Ribosomes are self-assembling macromolecular machines that translate DNA into proteins, and an understanding of ribosome biogenesis is central to cellular physiology. Previous studies on the Escherichia coli 30S subunit suggest that ribosome assembly occurs via multiple parallel pathways rather than through a single rate-limiting step, but little mechanistic information is known about this process. Discovery single-particle profiling (DSP), an application of time-resolved electron microscopy, was used to obtain more than 1 million snapshots of assembling 30S subunits, identify and visualize the structures of 14 assembly intermediates, and monitor the population flux of these intermediates over time. DSP results were integrated with mass spectrometry data to construct the first ribosome-assembly mechanism that incorporates binding dependencies, rate constants, and structural characterization of populated intermediates. PMID:21030658

  6. All-atom homology model of the Escherichia coli 30S ribosomal subunit.

    PubMed

    Tung, Chang-Shung; Joseph, Simpson; Sanbonmatsu, Kevin Y

    2002-10-01

    Understanding the structural basis of ribosomal function requires close comparison between biochemical and structural data. Although a large amount of biochemical data are available for the Escherichia coli ribosome, the structure has not been solved to atomic resolution. Using a new RNA homology procedure, we have modeled the all-atom structure of the E. coli 30S ribosomal subunit. We find that the tertiary structure of the ribosome core, including the A-, P- and E-sites, is highly conserved. The hypervariable regions in our structure, which differ from the structure of the 30S ribosomal subunit from Thermus thermophilus, are consistent with the cryo-EM map of the E. coli ribosome. PMID:12244297

  7. Power and peak blood lactate at 5050 m with 10 and 30 s 'all out' cycling.

    PubMed

    Grassi, B; Mognoni, P; Marzorati, M; Mattiotti, S; Marconi, C; Cerretelli, P

    2001-07-01

    Anecdotal observations suggest that the reduction in peak lactate accumulation in blood ([La]b peak) after exhausting exercise, in chronic hypoxia vs. normoxia, may be related to the duration of the exercise protocol, being less pronounced after short supramaximal exercise than after incremental exercise (IE) lasting several minutes. To test this hypothesis, six healthy male Caucasians (age 36.8 +/- 7.3, X +/- SD) underwent three exercise protocols on a cycle ergometer, at sea level (SL) and after 21 +/- 10 days at 5050 m altitude (ALT): (1) 10 s, (2) 30 s 'all out' exercise and (3) IE leading to exhaustion in approximately 20-25 min. 'Average' power output (P) was calculated for 10 or 30 s 'all out'; maximal power output (Pmax) was determined for IE. Lactate concentration in arterialized capillary blood ([La]b) was measured at rest and at different times during recovery; the highest [La]b during recovery was taken as [La]b peak. No significant differences in P were observed between SL and ALT, for either 10 or 30 s 'all out' exercise; Pmax during IE was significantly lower at ALT than at SL. [La]b peak after 10 s 'all out' was unaffected by chronic hypoxia (7.0 +/- 0.9 at ALT vs. 6.3 +/- 1.8 mmol x L(-1) at SL). After 30 s 'all out' the [La]b peak decrease, at ALT (10.6 +/- 0.6 mmol x L(-1)) vs. SL (12.9 +/- 1.4 mmol x L(-1)), was only approximately 50% of that observed for IE (6.7 +/- 1.6 mmol x L(-1) vs. 11.3 +/- 2.8 mmol x L(-1)). Muscle power output and blood lactate accumulation during short supramaximal exercise are substantially unaffected by chronic hypoxia. PMID:11472305

  8. Neutron Scattering and the 30 S Ribosomal Subunit of E. Coli

    DOE R&D Accomplishments Database

    Moore, P. B.; Engelman, D. M.; Langer, J. A.; Ramakrishnan, V. R.; Schindler, D. G.; Schoenborn, B. P.; Sillers, I. Y.; Yabuki, S.

    1982-06-01

    This paper reviews the progress made in the study of the internal organization of the 30 S ribosomal subunit of E. coli by neutron scattering since 1975. A map of that particle showing the position of 14 of the subunit's 21 proteins is presented, and the methods currently used for collecting and analyzing such data are discussed. Also discussed is the possibility of extending the interpretation of neutron mapping data beyond the limits practical today.

  9. Growth, Persistence, and Desistance of Alcohol Use for At-Risk Men in Their 30s

    PubMed Central

    Capaldi, Deborah M.; Tiberio, Stacey S.; Washburn, Isaac J.; Yoerger, Karen; Feingold, Alan

    2015-01-01

    Background Little is known about heterogeneity in men's drinking behaviors and their related consequences across midadulthood, and moreover, whether individual or social factors may predict such differences. The present study examined 3 indicators of alcohol use; namely, alcohol volume, heavy episodic drinking (HED), and drinking-related problems for men in their 30s. Methods Participants were 197 at-risk men from the Oregon Youth Study assessed 5 times across ages 29–38 years. Growth mixture modeling with count outcomes was used to examine unobserved heterogeneity in alcohol trajectories. Associations of latent classes of alcohol users with (i) classes for the other alcohol indicators, (ii) alcohol use by peers and romantic partners, (iii) alcohol classes previously extracted from ages 18–29 years, and (iv) past year alcohol use disorder (AUD) diagnostic status at ages 35–36 years was examined. Results A 3-class solution afforded the best fit for each alcohol indicator. Alcohol problems were relatively established in the 30s, with an ascending use class found only for volume. Although relatively few men were in higher classes for all 3 indicators, 45% of the sample was in the highest class on at least 2 indicators of use. Peer drunkenness was a robust predictor of the alcohol classes. Concordance among classes of alcohol users was seen from the 20s to the 30s, with prior desistance likely to be maintained for alcohol volume and HED. AUD diagnoses at ages 35–36 years were more common in the higher classes obtained for alcohol volume and alcohol problems. Conclusions Many men in their 30s engaged in high volume of alcohol without frequent engagement in HED, likely relating to continuing alcohol problems. The convergence of men's alcohol use with that of their peers found at younger ages was maintained into early midadulthood. PMID:26010338

  10. Detection of mRNA sequences in nuclear 30S ribonucleoprotein subcomplexes.

    PubMed Central

    Kinniburgh, A J; Martin, T E

    1976-01-01

    RNA from nuclear 30S ribonucleoprotein (RNP) complexes of mouse ascites cells has been shows to contain sequences homologous to poly(A) + mRNA by its ability to hybridize with complementary DNA prepared from poly(A) + mRNA template. Analysis of the hybridization kinetics of poly(A) + mRNA with its own complementary DNA revealed several abundancy classes. The total complexity of poly(A) + mRNA from ascites cells was estimated to be approximately 30,000 sequences of average molecular weight (6 X 10(5)). When the hybridization reaction of 30S RNP-RNA with mRNA-specific cDNA was compared to the homologous reaction the majority, and most probably all, of the poly(A) + mRNA sequences were found to be present in the RNA. The kinetics of hybridization suggest that 10-15% of the RNA in this RNP complex is homologous to poly(A) + mRNA. The 30S RNP subcomplexes therefore contain nuclear poly(A) + mRNA sequences as well as the bulk of heterogeneous RNA. PMID:1066686

  11. A role for the 30S subunit E site in maintenance of the translational reading frame

    PubMed Central

    Devaraj, Aishwarya; Shoji, Shinichiro; Holbrook, Eric D.; Fredrick, Kurt

    2009-01-01

    The exit (E) site has been implicated in several ribosomal activities, including translocation, decoding, and maintenance of the translational reading frame. Here, we target the 30S subunit E site by introducing a deletion in rpsG that truncates the β-hairpin of ribosomal protein S7. This mutation (S7ΔR77–Y84) increases both −1 and +1 frameshifting but does not increase miscoding, providing evidence that the 30S E site plays a specific role in frame maintenance. Mutation S7ΔR77–Y84 also stimulates +1 programmed frameshifting during prfB′-lacZ translation in many synthetic contexts. However, no effect is seen when the E codon of the frameshift site corresponds to those found in nature, suggesting that E-tRNA release does not normally limit the rate of prfB frameshifting. Ribosomes containing S7ΔR77–Y84 exhibit an elevated rate of spontaneous reverse translocation and an increased K 1/2 for E-tRNA. These effects are of similar magnitude, suggesting that both result from destabilization of E-tRNA. Finally, this mutation of the 30S E site does not inhibit EF-G-dependent translocation, consistent with a primary role for the 50S E site in the mechanism. PMID:19095617

  12. Concurrent Nucleation of 16S Folding and Induced Fit in 30S Ribosome Assembly

    SciTech Connect

    Adilakshmi, T.; Bellur, D; Woodson, S

    2008-01-01

    Rapidly growing cells produce thousands of new ribosomes each minute, in a tightly regulated process that is essential to cell growth. How the Escherichia coli 16S ribosomal RNA and the 20 proteins that make up the 30S ribosomal subunit can assemble correctly in a few minutes remains a challenging problem, partly because of the lack of real-time data on the earliest stages of assembly. By providing snapshots of individual RNA and protein interactions as they emerge in real time, here we show that 30S assembly nucleates concurrently from different points along the rRNA. Time-resolved hydroxyl radical footprinting3 was used to map changes in the structure of the rRNA within 20 milliseconds after the addition of total 30S proteins. Helical junctions in each domain fold within 100 ms. In contrast, interactions surrounding the decoding site and between the 5', the central and the 3' domains require 2-200 seconds to form. Unexpectedly, nucleotides contacted by the same protein are protected at different rates, indicating that initial RNA-protein encounter complexes refold during assembly. Although early steps in assembly are linked to intrinsically stable rRNA structure, later steps correspond to regions of induced fit between the proteins and the rRNA.

  13. Polar stratospheric clouds as deduced from MLS and CLAES measurements

    SciTech Connect

    Ricaud, P.D.; Carr, E.S.; Harwood, R.S.; Lahoz, W.A.

    1995-08-01

    From 30 August 1992 to 3 September 1992 a supersaturated area at 465 K potential temperature ({approximately}50 hPa) is deduced from MLS water vapour measurements over western Antarctica, where high extinction coefficients measured by CLAES indicate Polar Stratospheric Clouds (PSCs). These PSCs are attributed partly to the effect of an anticyclone located over South America and partly to localized orographic waves, which raise the isentropes and generate rapid adiabatic cooling. A local minimum in column O{sub 3} ({<=}200DU) is observed in this area, which is believed to be a consequence of the dynamics. Enhanced ClO abundances downstream of the region indicate PSC processing and chlorine activation. 18 refs., 2 figs.

  14. Crystal Structure of the 30S Ribosomal Subunit from Thermus Thermophilus. Purification, Crystallization and Structure Determination

    SciTech Connect

    Clemons, William M.; Brodersen, Ditlev E.; McCutcheonn, John P.; May, Joanna L.C.; Carter, Andrew P.; Morgan-Warren, Robert J.; Wimberly, Brian T.; Ramakrishnan, Venki

    2009-10-07

    We describe the crystallization and structure determination of the 30 S ribosomal subunit from Thermus thermophilus. Previous reports of crystals that diffracted to 10 {angstrom} resolution were used as a starting point to improve the quality of the diffraction. Eventually, ideas such as the addition of substrates or factors to eliminate conformational heterogeneity proved less important than attention to detail in yielding crystals that diffracted beyond 3 {angstrom} resolution. Despite improvements in technology and methodology in the last decade, the structure determination of the 30 S subunit presented some very challenging technical problems because of the size of the asymmetric unit, crystal variability and sensitivity to radiation damage. Some steps that were useful for determination of the atomic structure were: the use of anomalous scattering from the LIII edges of osmium and lutetium to obtain the necessary phasing signal; the use of tunable, third-generation synchrotron sources to obtain data of reasonable quality at high resolution; collection of derivative data precisely about a mirror plane to preserve small anomalous differences between Bijvoet mates despite extensive radiation damage and multi-crystal scaling; the pre-screening of crystals to ensure quality, isomorphism and the efficient use of scarce third-generation synchrotron time; pre-incubation of crystals in cobalt hexaammine to ensure isomorphism with other derivatives; and finally, the placement of proteins whose structures had been previously solved in isolation, in conjunction with biochemical data on protein-RNA interactions, to map out the architecture of the 30 S subunit prior to the construction of a detailed atomic-resolution model.

  15. Low-latitude field-aligned currents deduced by Swarm

    NASA Astrophysics Data System (ADS)

    Lühr, Hermann; Kervalishvili, Guram; Rauberg, Jan

    2015-04-01

    ESA's constellation mission Swarm was successfully launched on 22 November 2013. The three satellites are orbiting the Earth at 470 km and 520 km altitude. The lower pair Swarm-A and C is flying side-by-side separated by only 1.4° in latitude. Magnetic field readings of this pair are used to determine for the first time field-aligned currents (FAC) uniquely in the ionosphere. Of particular interest for this presentation are FACs at low and equatorial latitudes. Indications for several of such current systems have been deduced from CHAMP observations. Examples to be studied are meridional and vertical currents driven by the F-region dynamo. They are expected to show opposite polarities between noon and sunset. Likewise there are FACs expected to balance the electric potential differences between the foci of the Sq current vortices in the two hemispheres, which should be most prominent during solstice seasons. Another example is the FAC associated with equatorial plasma bubbles. They are expected to flow along the walls of the electron density depleted volume. Due to the limited amount of suitable Swarm data we will focus on June solstice and September equinox 2014 for this presentation.

  16. Deducing high-altitude precipitation from glacier mass balance measurements

    NASA Astrophysics Data System (ADS)

    Giesen, Rianne H.; Immerzeel, Walter W.; Wanders, Niko

    2016-04-01

    The spatial distribution of precipitation in mountainous terrain is generally not well known due to underrepresentation of gauge observations at higher elevations. Precipitation tends to increase with elevation, but since observations are mainly performed in the valleys, the vertical precipitation gradient cannot be deduced from these measurements. Furthermore, the spatial resolution of gridded meteorological data is often too coarse to resolve individual mountain chains. Still, a reliable estimate of high-elevation precipitation is required for many hydrological applications. We present a method to determine the vertical precipitation gradient in mountainous terrain, making use of glacier mass balance observations. These measurements have the advantage that they provide a basin-wide precipitation estimate at high elevations. The precipitation gradient is adjusted until the solid precipitation over the glacier area combined with the calculated melt gives the measured annual glacier mass balance. Results for the glacierized regions in Central Europe and Scandinavia reveal spatially coherent patterns, with predominantly positive precipitation gradients ranging from -4 to +28 % (100 m)‑1. In some regions, precipitation amounts at high elevations are up to four times as large as in the valleys. A comparison of the modelled winter precipitation with observed snow accumulation on glaciers shows a good agreement. Precipitation measured at the few high-altitude meteorological stations is generally lower than our estimate, which may result from precipitation undercatch. Our findings will improve the precipitation forcing for glacier modelling and hydrological studies in mountainous terrain.

  17. Characterization of GE82832, a peptide inhibitor of translocation interacting with bacterial 30S ribosomal subunits

    PubMed Central

    Brandi, Letizia; Fabbretti, Attilio; Stefano, Michele Di; Lazzarini, Ameriga; Abbondi, Monica; Gualerzi, Claudio O.

    2006-01-01

    GE82832, a secondary metabolite produced by Streptosporangium cinnabarinum (strain GE82832), has been identified as a translational inhibitor by in vitro screening of a library of natural products. Secondary functional tests specific for individual steps of the translational pathway demonstrated that translocation is the specific target of GE82832. Chemical probing in situ demonstrated that this antibiotic protects bases A1324 and A1333 and exposes C1336 of 16S rRNA, thereby indicating that its binding site is located on the head of the 30S ribosomal subunit. The ribosomal location of GE82832, near ribosomal protein S13 and G1338, two elements of the small subunit that are part of or close to the B1a intrasubunit bridge, suggests that translocation inhibition results from an altered dynamics of 30S–50S ribosomal subunit interaction. PMID:16699167

  18. Anaerobic energy release in working muscle during 30 s to 3 min of exhausting bicycling.

    PubMed

    Medbø, J I; Tabata, I

    1993-10-01

    To examine the anaerobic energy release during intense exercise, 16 healthy young men cycled as long as possible at constant powers chosen to exhaust the subjects in approximately 30 s, 1 min, or 2-3 min. Muscle biopsies were taken before and approximately 10 s after exercise and analyzed for lactate, phosphocreatine (PCr), and other metabolites. O2 uptake was measured for determination of the accumulated O2 deficit (a whole body measure of the anaerobic energy release), and this indirect measure of the anaerobic energy release was compared with a direct value obtained from measured muscle metabolites. Muscle lactate concentration rose by 30.0 +/- 1.2 mmol/kg and muscle PCr concentration fell by 12.4 +/- 0.9 mmol/kg during the 2-3 min of exhausting exercise. The anaerobic ATP production was consequently 58 +/- 2 mmol/kg wet muscle mass, which may be the maximum anaerobic energy release for human muscle during bicycling. Because the anaerobic ATP production was 6 and 32% less for 1 min and 30 s of exercise, respectively, than for 2 min of exercise (P < 0.03), 2 min of exhausting exercise may be required for maximal use of anaerobic sources. Lactate production provided three times more ATP than PCr breakdown for all three exercise durations. There was a close linear relationship between the rates of anaerobic ATP production in muscle and the value estimated for the whole body by the O2 deficit (r = 0.94). This suggests that the accumulated O2 deficit is a valid measure of the anaerobic energy release during bicycling. PMID:8282617

  19. Switching off the tackiness of a nanocomposite adhesive in 30 s via infrared sintering.

    PubMed

    Gurney, Robert S; Dupin, Damien; Nunes, Juliana S; Ouzineb, Keltoum; Siband, Elodie; Asua, José M; Armes, Steven P; Keddie, Joseph L

    2012-10-24

    Soft adhesives require an optimum balance of viscous and elastic properties. Adhesion is poor when the material is either too solidlike or too liquidlike. The ability to switch tack adhesion off at a desired time has many applications, such as in recycling, disassembly of electronics, and painless removal of wound dressings. Here, we describe a new strategy to switch off the tack adhesion in a model nanocomposite adhesive in which temperature is the trigger. The nanocomposite comprises hard methacrylic nanoparticles blended with a colloidal dispersion of soft copolymer particles. At relatively low volume fractions, the nanoparticles (50 nm diameter) accumulate near the film surface, where they pack around the larger soft particles (270 nm). The viscoelasticity of the nanocomposite is adjusted via the nanoparticle concentration. When the nanocomposite is heated above the glass transition temperature of the nanoparticles (T(g) = 130 °C), they sinter together to create a rigid network that raises the elastic modulus at room temperature. The tackiness is switched off. Intense infrared radiation is used to heat the nanocomposites, leading to a fast temperature rise. Tack adhesion is switched off within 30 s in optimized compositions. These one-way switchable adhesives have the potential to be patterned through localized heating. PMID:22974179

  20. Motives for physical activity among active and inactive persons in their mid-30s.

    PubMed

    Aaltonen, S; Rottensteiner, M; Kaprio, J; Kujala, U M

    2014-08-01

    The purpose of this study was to examine the motives for leisure-time physical activity among active and inactive men and women in their mid-30s. We used both cross-sectional and longitudinal designs. Altogether, 2308 participants (mean age 33.9 years, 53.4% women) were identified from the population-based FinnTwin16 Cohort. Physically active and inactive individuals were identified on the basis of their leisure-time MET h/day. We evaluated participants' physical activity motivation with a modified version of the Recreational Exercise Motivation Measure. Comparisons between active and inactive individuals were analysed using the Wald test for equality of means, and effect sizes were calculated as Cohen's d. Motives related to mastery, physical fitness, social aspect of physical activity, psychological state, enjoyment, willingness to be fitter/look better than others, and appearance were significantly more important for the active than inactive participants. Conforming to others' expectations was the only item on which the inactive persons scored higher than active persons. The longitudinal results for physical activity were parallel to the cross-sectional results. This study supports the view that motivation factors differ between active and inactive persons, and that intrinsic motives are associated with consistent leisure-time physical activity. PMID:23331765

  1. Advance of the perihelion of Mercury deduced from QFT

    NASA Astrophysics Data System (ADS)

    Chen, Shao-Guang

    I deduce the new gravitational formula from the variance in mass of QFT and GR (H05-0029-08, E15-0039 -08, E14-0032-08, D31-0054-10) in the partial differential: f (QFT) = f (GR) = delta∂ (m v)/delta∂ t = f _{P} + f _{C} , f _{P} = m delta∂ v / delta∂ t = - ( G m M /r (2) ) r / r, f _{C} = v delta∂ m / delta∂ t = - ( G m M / r (2) ) v / c (1), f (QFT) is the quasi-Casimir pressure of net virtual neutrinos nuν _{0} flux (after counteract contrary direction nuν _{0}). f (GR) is equivalent to Einstein’s equation, Eq. (1) is a new version of GR and can be solved exactly. Its core content is that the gravity produced by particles collide cannot linear addition, i.e., the nonlinearity of Einstein equation had been replaced by the nonlinearity caused by the variable mass in Eq.(1). Einstein equation can be inferred from Eq.(1) thereby from QFT, but QFT cannot be inferred from Eq.(1) or GR. f (QFT) is essential but f (GR) is phenomenological. Eq.(1) is obtained just by to absorb the essence of corpuscule collided gravitation origin ism proposed by Fatio in 1690 and 1920 Majorana’s experiment concept about gravitational shield effect again fuse with QFT. In my paper ‘QFT’S advance of the perihelion of Mercury, China Science &Technology Overview 125 88-90 (2011)’ QFT gravitational potential U = - G M /r is just the distribution density of net nuν _{0} flux, from SR we again get that: f (QFT) = f _{P} + f _{C}, f _{P} = - m ( delta∂ U / delta∂ r) r / r, f _{C} = - m ( delta∂U / delta∂ r) v / c (2), f _{ P} correspond the change rate of three-dimensional momentum p, f _{C} correspond the change rate of fourth dimensional momentum i m c which show directly as a dissipative force of mass change. According to Eq.(2) the circular motion is instability and elliptic motion is in the auto-stability state. In the fluctuation vacuum a particle with mass M neighbor another particle with mass m, the renormalization mass M and m will be less than that when

  2. Characteristics of a long-pulse (30-s), high-power (4-MW) ion source for neutral beam injection

    SciTech Connect

    Menon, M.M.; Barber, G.C.; Combs, S.K.; Dagenhart, W.K.; Gardner, W.L.; Haselton, H.H.; Moeller, J.A.; Ponte, N.S.; Ryan, P.M.; Schechter, D.E.

    1983-01-01

    A quasi-steady-state ion source has been developed for neutral beam injection applications. It is of the duoPIGatron type designed for delivering 50 A of hydrogen ions at 80 keV for 30-s-long pulses. Ion beams of 40 A at 75 keV were extracted for pulse lengths up to 30 s, maintaining excellent optical quality in the beam for the entire pulse duration. The design features and operational characteristics of the ion source are elaborated.

  3. PPARA intron polymorphism associated with power performance in 30-s anaerobic Wingate Test.

    PubMed

    Petr, Miroslav; Stastny, Petr; Št'astný, Petr; Pecha, Ondřej; Šteffl, Michal; Šeda, Ondřej; Kohlíková, Eva

    2014-01-01

    To date, polymorphisms in several genes have been associated with a strength/power performance including alpha 3 actinin, ciliary neurotrophic factor, vitamin D receptor, or angiotensin I converting enzyme, underlining the importance of genetic component of the multifactorial strength/power-related phenotypes. The single nucleotide variation in peroxisome proliferator-activated receptor alpha gene (PPARA) intron 7 G/C (rs4253778; g.46630634G>C) has been repeatedly found to play a significant role in response to different types of physical activity. We investigated the effect of PPARA intron 7 G/C polymorphism specifically on anaerobic power output in a group of 77 elite male Czech ice hockey players (18-36 y). We determined the relative peak power per body weight (Pmax.kg(-1)) and relative peak power per fat free mass (W.kg(-1)FFM) during the 30-second Wingate Test (WT30) on bicycle ergometer (Monark 894E Peak bike, MONARK, Sweden). All WT30s were performed during the hockey season. Overall genotype frequencies were 50.6% GG homozygotes, 40.3% CG heterozygotes, and 9.1% CC homozygotes. We found statistically significant differences in Pmax.kg(-1) and marginally significant differences in Pmax.kg(-1)FFM values in WT30 between carriers and non-carriers for C allele (14.6 ± 0.2 vs. 13.9 ± 0.3 W.kg(-1) and 15.8 ± 0.2 vs. 15.2 ± 0.3 W.kg(-1)FFM, P = 0.036 and 0.12, respectively). Furthermore, Pmax.kg(-1)FFM strongly positively correlated with the body weight only in individuals with GG genotypes (R = 0.55; p<0.001). Our results indicate that PPARA 7C carriers exhibited higher speed strength measures in WT30. We hypothesize that C allele carriers within the cohort of trained individuals may possess a metabolic advantage towards anaerobic metabolism. PMID:25198533

  4. Advance of the perihelion of Mercury deduced from QFT

    NASA Astrophysics Data System (ADS)

    Chen, Shao-Guang

    I deduce the new gravitational formula from the variance in mass of QFT and GR (H05-0029-08, E15-0039 -08, E14-0032-08, D31-0054-10) in the partial differential: f (QFT) = f (GR) = delta∂ (m v)/delta∂ t = f _{P} + f _{C} , f _{P} = m delta∂ v / delta∂ t = - ( G m M /r (2) ) r / r, f _{C} = v delta∂ m / delta∂ t = - ( G m M / r (2) ) v / c (1), f (QFT) is the quasi-Casimir pressure of net virtual neutrinos nuν _{0} flux (after counteract contrary direction nuν _{0}). f (GR) is equivalent to Einstein’s equation, Eq. (1) is a new version of GR and can be solved exactly. Its core content is that the gravity produced by particles collide cannot linear addition, i.e., the nonlinearity of Einstein equation had been replaced by the nonlinearity caused by the variable mass in Eq.(1). Einstein equation can be inferred from Eq.(1) thereby from QFT, but QFT cannot be inferred from Eq.(1) or GR. f (QFT) is essential but f (GR) is phenomenological. Eq.(1) is obtained just by to absorb the essence of corpuscule collided gravitation origin ism proposed by Fatio in 1690 and 1920 Majorana’s experiment concept about gravitational shield effect again fuse with QFT. In my paper ‘QFT’S advance of the perihelion of Mercury, China Science &Technology Overview 125 88-90 (2011)’ QFT gravitational potential U = - G M /r is just the distribution density of net nuν _{0} flux, from SR we again get that: f (QFT) = f _{P} + f _{C}, f _{P} = - m ( delta∂ U / delta∂ r) r / r, f _{C} = - m ( delta∂U / delta∂ r) v / c (2), f _{ P} correspond the change rate of three-dimensional momentum p, f _{C} correspond the change rate of fourth dimensional momentum i m c which show directly as a dissipative force of mass change. According to Eq.(2) the circular motion is instability and elliptic motion is in the auto-stability state. In the fluctuation vacuum a particle with mass M neighbor another particle with mass m, the renormalization mass M and m will be less than that when

  5. Conformation of 4.5S RNA in the signal recognition particle and on the 30S ribosomal subunit

    PubMed Central

    GU, SHAN-QING; JÖCKEL, JOHANNES; BEINKER, PHILIPP; WARNECKE, JENS; SEMENKOV, YURI P.; RODNINA, MARINA V.; WINTERMEYER, WOLFGANG

    2005-01-01

    The signal recognition particle (SRP) from Escherichia coli consists of 4.5S RNA and protein Ffh. It is essential for targeting ribosomes that are translating integral membrane proteins to the translocation pore in the plasma membrane. Independently of Ffh, 4.5S RNA also interacts with elongation factor G (EF-G) and the 30S ribosomal subunit. Here we use a cross-linking approach to probe the conformation of 4.5S RNA in SRP and in the complex with the 30S ribosomal subunit and to map the binding site. The UV-activatable cross-linker p-azidophenacyl bromide (AzP) was attached to positions 1, 21, and 54 of wild-type or modified 4.5S RNA. In SRP, cross-links to Ffh were formed from AzP in all three positions in 4.5S RNA, indicating a strongly bent conformation in which the 5′ end (position 1) and the tetraloop region (including position 54) of the molecule are close to one another and to Ffh. In ribosomal complexes of 4.5S RNA, AzP in both positions 1 and 54 formed cross-links to the 30S ribosomal subunit, independently of the presence of Ffh. The major cross-linking target on the ribosome was protein S7; minor cross-links were formed to S2, S18, and S21. There were no cross-links from 4.5S RNA to the 50S subunit, where the primary binding site of SRP is located close to the peptide exit. The functional role of 4.5S RNA binding to the 30S subunit is unclear, as the RNA had no effect on translation or tRNA translocation on the ribosome. PMID:16043501

  6. CONSISTENT USE OF THE KALMAN FILTER IN CHEMICAL TRANSPORT MODELS (CTMS) FOR DEDUCING EMISSIONS

    EPA Science Inventory

    Past research has shown that emissions can be deduced using observed concentrations of a chemical, a Chemical Transport Model (CTM), and the Kalman filter in an inverse modeling application. An expression was derived for the relationship between the "observable" (i.e., the con...

  7. The French Zones d'Education Prioritaire: Much Ado about Nothing?

    ERIC Educational Resources Information Center

    Benabou, Roland; Kramarz, Francis; Prost, Corinne

    2009-01-01

    We provide an assessment of the French ZEP (Zones d'Education Prioritaire), a program started in 1982 that channels additional resources to schools in disadvantaged areas and encourages the development of new teaching projects. Focusing on middle-schools, we first evaluate the impact of the ZEP status on resources, their utilization (teacher…

  8. Haiti: Incentives To Improve Basic Education (IIBE)--Project Bilaterial d'Education (PROBED). Midterm Evaluation.

    ERIC Educational Resources Information Center

    Locher, Uli; And Others

    Haiti's Incentives to Improve Basic Education (IIBE) or Project Bilteral d'Education (PROBED) program seeks to stimulate improvements in educational quality and efficiency in private primary schools. The program surpasses other efforts because of: (1) unusually thorough preparation; (2) rapid assumption of management by Haitians; (3) a…

  9. Depletion of Free 30S Ribosomal Subunits in Escherichia coli by Expression of RNA Containing Shine-Dalgarno-Like Sequences

    PubMed Central

    Mawn, Mary V.; Fournier, Maurille J.; Tirrell, David A.; Mason, Thomas L.

    2002-01-01

    We have constructed synthetic coding sequences for the expression of poly(α,l-glutamic acid) (PLGA) as fusion proteins with dihydrofolate reductase (DHFR) in Escherichia coli. These PLGA coding sequences use both GAA and GAG codons for glutamic acid and contain sequence elements (5′-GAGGAGG-3′) that resemble the consensus Shine-Dalgarno (SD) sequence found at translation initiation sites in bacterial mRNAs. An unusual feature of DHFR-PLGA expression is that accumulation of the protein is inversely related to the level of induction of its mRNA. Cellular protein synthesis was inhibited >95% by induction of constructs for either translatable or untranslatable PLGA RNAs. Induction of PLGA RNA resulted in the depletion of free 30S ribosomal subunits and the appearance of new complexes in the polyribosome region of the gradient. Unlike normal polyribosomes, these complexes were resistant to breakdown in the presence of puromycin. The novel complexes contained 16S rRNA, 23S rRNA, and PLGA RNA. We conclude that multiple noninitiator SD-like sequences in the PLGA RNA inhibit cellular protein synthesis by sequestering 30S small ribosomal subunits and 70S ribosomes in nonfunctional complexes on the PLGA mRNA. PMID:11751827

  10. Differential effects of ribosomal proteins and Mg2+ ions on a conformational switch during 30S ribosome 5'-domain assembly.

    PubMed

    Abeysirigunawardena, Sanjaya C; Woodson, Sarah A

    2015-11-01

    Ribosomal protein S4 nucleates assembly of the 30S ribosome 5' and central domains, which is crucial for the survival of cells. Protein S4 changes the structure of its 16S rRNA binding site, passing through a non-native intermediate complex before forming native S4-rRNA contacts. Ensemble FRET was used to measure the thermodynamic stability of non-native and native S4 complexes in the presence of Mg(2+) ions and other 5'-domain proteins. Equilibrium titrations of Cy3-labeled 5'-domain RNA with Cy5-labeled protein S4 showed that Mg(2+) ions preferentially stabilize the native S4-rRNA complex. In contrast, ribosomal proteins S20 and S16 act by destabilizing the non-native S4-rRNA complex. The full cooperative switch to the native complex requires S4, S16, and S20 and is achieved to a lesser degree by S4 and S16. The resulting thermodynamic model for assembly of the 30S body illustrates how ribosomal proteins selectively bias the equilibrium between alternative rRNA conformations, increasing the cooperativity of rRNA folding beyond what can be achieved by Mg(2+) ions alone. PMID:26354770

  11. Positions of S2, S13, S16, S17, S19 and S21 in the 30 S ribosomal subunit of Escherichia coli.

    PubMed

    Capel, M S; Kjeldgaard, M; Engelman, D M; Moore, P B

    1988-03-01

    Neutron scattering distance data are presented for 33 protein pairs in the 30 S ribosomal subunit from Escherichia coli, along with the methods used for measuring distances between its exchangeable components. When combined with prior data, these new results permit the positioning of S2, S13, S16, S17, S19 and S21 in the 30 S ribosomal subunit, completing the mapping of its proteins by neutron scattering. Comparisons with other data suggest that the neutron map is a reliable guide to the quaternary structure of the 30 S subunit. PMID:3288761

  12. Comparisons of Satellite-Deduced Overlapping Cloud Properties and CALIPSO CloudSat Data

    NASA Technical Reports Server (NTRS)

    Chang, Fu-Lung; Minnis, Patrick; Lin, Bing; Sun-Mack, Sunny

    2010-01-01

    Introduction to the overlapped cloud properties derived from polar-orbiting (MODIS) and geostationary (GOES-12, -13, Meteosat-8, -9, etc.) meteorological satellites, which are produced at the NASA Langley Research Center (LaRC) cloud research & development team (NASA lead scientist: Dr. Patrick Minnis). Comparison of the LaRC CERES MODIS Edition-3 overlapped cloud properties to the CALIPSO and the CloudSat active sensing data. High clouds and overlapped clouds occur frequently as deduced by CALIPSO (44 & 25%), CloudSat (25 & 4%), and MODIS (37 & 6%). Large fractions of optically-thin cirrus and overlapped clouds are deduced from CALIPSO, but much smaller fractions are from CloudSat and MODIS. For overlapped clouds, the averaged upper-layer CTHs are about 12.8 (CALIPSO), 10.9 (CloudSat) and 10 km (MODIS), and the averaged lower-layer CTHs are about 3.6 (CALIPSO), 3.2 (CloudSat) and 3.9 km (MODIS). Based on comparisons of upper and lower-layer cloud properties as deduced from the MODIS, CALIPSO and CloudSat data, more enhanced passive satellite methods for retrieving thin cirrus and overlapped cloud properties are needed and are under development.

  13. Deducing lightning locations and charge moment change by ELF observations around Japan

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Hobara, Y.; Hayakawa, M.; Shiokawa, K.

    2011-12-01

    The electromagnetic radiations from lightning discharges have been intensively studied for a long time by using different frequency ranges. Recent observations of electromagnetic radiations from lightning in the ELF frequency range so-called ELF transients are recognized as a powerful tool not only to deduce the global lightning distribution but also to obtain one of the most important properties of lightning discharges such as charge moment changes (Qds). Although accurate Qds for the lightning discharges can be deduced from the static electric field measurement by using e.g. electric field mill, the detection ranges of this equipment is significantly limited in space (typically within few decade of km). Therefore Qds distributions of local thunderstorm activities over the spatial scale of Japan (within few thousands km) have not been studied yet. In this paper, we report the initial results of local ELF network observations (i.e. multiple observations over Japan) to deduce the spatio-temporal lightning discharge distributions with a charge moment change of the thunderstorm activity around Japan. The statistical properties of the charge moment changes will be presented as well.

  14. The DEDUCE Guided Query tool: providing simplified access to clinical data for research and quality improvement.

    PubMed

    Horvath, Monica M; Winfield, Stephanie; Evans, Steve; Slopek, Steve; Shang, Howard; Ferranti, Jeffrey

    2011-04-01

    In many healthcare organizations, comparative effectiveness research and quality improvement (QI) investigations are hampered by a lack of access to data created as a byproduct of patient care. Data collection often hinges upon either manual chart review or ad hoc requests to technical experts who support legacy clinical systems. In order to facilitate this needed capacity for data exploration at our institution (Duke University Health System), we have designed and deployed a robust Web application for cohort identification and data extraction--the Duke Enterprise Data Unified Content Explorer (DEDUCE). DEDUCE is envisioned as a simple, web-based environment that allows investigators access to administrative, financial, and clinical information generated during patient care. By using business intelligence tools to create a view into Duke Medicine's enterprise data warehouse, DEDUCE provides a Guided Query functionality using a wizard-like interface that lets users filter through millions of clinical records, explore aggregate reports, and, export extracts. Researchers and QI specialists can obtain detailed patient- and observation-level extracts without needing to understand structured query language or the underlying database model. Developers designing such tools must devote sufficient training and develop application safeguards to ensure that patient-centered clinical researchers understand when observation-level extracts should be used. This may mitigate the risk of data being misunderstood and consequently used in an improper fashion. PMID:21130181

  15. Escherichia coli rimM and yjeQ null strains accumulate immature 30S subunits of similar structure and protein complement

    PubMed Central

    Leong, Vivian; Kent, Meredith; Jomaa, Ahmad; Ortega, Joaquin

    2013-01-01

    Assembly of the Escherichia coli 30S ribosomal subunits proceeds through multiple parallel pathways. The protein factors RimM, YjeQ, RbfA, and Era work in conjunction to assist at the late stages of the maturation process of the small subunit. However, it is unclear how the functional interplay between these factors occurs in the context of multiple parallel pathways. To understand how these factors work together, we have characterized the immature 30S subunits that accumulate in ΔrimM cells and compared them with immature 30S subunits from a ΔyjeQ strain. The cryo-EM maps obtained from these particles showed that the densities representing helices 44 and 45 in the rRNA were partially missing, suggesting mobility of these motifs. These 30S subunits were also partially depleted in all tertiary ribosomal proteins, particularly those binding in the head domain. Using image classification, we identified four subpopulations of ΔrimM immature 30S subunits differing in the amount of missing density for helices 44 and 45, as well as the amount of density existing in these maps for the underrepresented proteins. The structural defects found in these immature subunits resembled those of the 30S subunits that accumulate in the ΔyjeQ strain. These findings are consistent with an “early convergency model” in which multiple parallel assembly pathways of the 30S subunit converge into a late assembly intermediate, as opposed to the mature state. Functionally related factors will bind to this intermediate to catalyze the last steps of maturation leading to the mature 30S subunit. PMID:23611982

  16. A combined quantitative mass spectrometry and electron microscopy analysis of ribosomal 30S subunit assembly in E. coli

    PubMed Central

    Sashital, Dipali G; Greeman, Candacia A; Lyumkis, Dmitry; Potter, Clinton S; Carragher, Bridget; Williamson, James R

    2014-01-01

    Ribosome assembly is a complex process involving the folding and processing of ribosomal RNAs (rRNAs), concomitant binding of ribosomal proteins (r-proteins), and participation of numerous accessory cofactors. Here, we use a quantitative mass spectrometry/electron microscopy hybrid approach to determine the r-protein composition and conformation of 30S ribosome assembly intermediates in Escherichia coli. The relative timing of assembly of the 3′ domain and the formation of the central pseudoknot (PK) structure depends on the presence of the assembly factor RimP. The central PK is unstable in the absence of RimP, resulting in the accumulation of intermediates in which the 3′-domain is unanchored and the 5′-domain is depleted for r-proteins S5 and S12 that contact the central PK. Our results reveal the importance of the cofactor RimP in central PK formation, and introduce a broadly applicable method for characterizing macromolecular assembly in cells. DOI: http://dx.doi.org/10.7554/eLife.04491.001 PMID:25313868

  17. S-adenosylmethionine directly inhibits binding of 30S ribosomal subunits to the SMK box translational riboswitch RNA

    PubMed Central

    Fuchs, Ryan T.; Grundy, Frank J.; Henkin, Tina M.

    2007-01-01

    The SMK box is a conserved riboswitch motif found in the 5′ untranslated region of metK genes [encoding S-adenosylmethionine (SAM) synthetase] in lactic acid bacteria, including Enterococcus, Streptococcus, and Lactococcus sp. Previous studies showed that this RNA element binds SAM in vitro, and SAM binding causes a structural rearrangement that sequesters the Shine–Dalgarno (SD) sequence by pairing with an anti-SD (ASD) element. A model was proposed in which SAM binding inhibits metK translation by preventing binding of the ribosome to the SD region of the mRNA. In the current work, the addition of SAM was shown to inhibit binding of 30S ribosomal subunits to SMK box RNA; in contrast, the addition of S-adenosylhomocysteine (SAH) had no effect. A mutant RNA, which has a disrupted SD-ASD pairing, was defective in SAM binding and showed no reduction of ribosome binding in the presence of SAM, whereas a compensatory mutation that restored SD-ASD pairing restored the response to SAM. Primer extension inhibition assays provided further evidence for SD-ASD pairing in the presence of SAM. These results strongly support the model that SMK box translational repression operates through occlusion of the ribosome binding site and that SAM binding requires the SD-ASD pairing. PMID:17360376

  18. Pollen analyses from a 50 000-yr rodent midden series in the southern Atacama Desert (25° 30 S)

    NASA Astrophysics Data System (ADS)

    Maldonado, Antonio; Betancourt, Julio L.; Latorre, Claudio; Villagran, Carolina

    2005-07-01

    Precipitation in northern Chile is controlled by two great wind belts - the southern westerlies over the southern Atacama and points south (> 24° S) and the tropical easterlies over the northern and central Atacama Desert (16-24° S). At the intersection of these summer and winter rainfall regimes, respectively, is a Mars-like landscape consisting of expansive surfaces devoid of vegetation (i.e. absolute desert) except in canyons that originate high enough to experience runoff once every few years. Pollen assemblages from 39 fossil rodent middens in one of these canyons, Quebrada del Chaco (25° 30 S), were used to infer the history of vegetation and precipitation at three elevations (2670-2800 m; 3100-3200 m; 3450-3500 m) over the past 50 000 years. When compared to modern conditions and fossil records to the north and south, the pollen evidence indicates more winter precipitation at > 52, 40-33, 24-17 k cal. yr BP, more precipitation in both seasons at 17-14 k cal. yr BP, and more summer precipitation from 14-11 k cal.yrBP. Younger middens are scarce at Quebrada del Chaco, and the few Holocene samples indicate hyperarid conditions comparable to today. The only exception is a pollen assemblage that indicates a brief but significant interlude of increased winter precipitation in the last millennium. Copyright

  19. Deduced primary structure of two forms of vitellogenin in Japanese common goby (Acanthogobius flavimanus).

    PubMed

    Ohkubo, N; Andoh, T; Mochida, K; Adachi, S; Hara, A; Matsubara, T

    2004-05-15

    Complete nucleotide sequences of two forms of vitellogenin (Vg) cDNA in Japanese common goby were determined from a liver cDNA library of E(2)-treated male fish. These two Vg cDNAs contained complete open reading frames encoding 1664 and 1238 amino acid residues including signal peptides, respectively. From comparison of the deduced amino acid sequences of both Vgs and the partial amino acid sequences of the yolk proteins, the longer sequence was concluded to be cDNA of the Vg-530 and the shorter one was that of the Vg-320 of the Japanese common goby which were reported in our previous paper. The deduced sequence of Vg-530 without signal peptide was arranged by lipovitellin heavy-chain (LvH), phosvitin (Pv), lipovitellin light-chain (LvL), and beta'-component beta'-c) domains from the N-terminus, and showed a range of 40-45% sequence identity to those of other fish. Furthermore, the deduced sequence of Vg-320 showed no obvious Pv domain, has a shortened C-terminal coding region after the LvH domain, and showed a close similarity to the phosvitin-less Vg of zebrafish. Moreover, biochemical analysis of the yolk proteins verified that Vg-530 cleaves into the Lv-Pv complex (molecular mass: 470 kDa) and beta'-c (33 kDa), while Vg-320 showed no change when incorporated into oocytes. The present study demonstrated the existence of the two different forms of Vgs at both the cDNA and protein level, and showed molecular alteration of the two Vgs during vitellogenesis. Two Vg sequence data will aid in designing nucleotide probes for detecting Vg gene expressions as a biomarker of environmental estrogens. PMID:15094332

  20. Family Planning and Preconception Health Among Men in Their Mid-30s: Developing Indicators and Describing Need.

    PubMed

    Casey, Frances E; Sonenstein, Freya L; Astone, Nan M; Pleck, Joseph H; Dariotis, Jacinda K; Marcell, Arik V

    2016-01-01

    The Centers for Disease Control and Prevention and Healthy People 2020 call for improvements in meeting men's reproductive health needs but little is known about the proportion of men in need. This study describes men aged 35 to 39 in need of family planning and preconception care, demographic correlates of these needs, and contraception use among men in need of family planning. Using data from Wave 4 (2008-2010) of the National Survey of Adolescent Males, men were classified in need of family planning and preconception care if they reported sex with a female in the last year and believed that they and their partner were fecund; the former included men who were neither intentionally pregnant nor intending future children and the latter included men intending future children. Men were classified as being in need of both if they reported multiple sex partners in the past year. About 40% of men aged 35 to 39 were in need of family planning and about 33% in need of preconception care with 12% in need of both. Current partner's age, current union type, and sexually transmitted infection health risk differentiated men in need of family planning and preconception care (all ps < .01) and participants' race/ethnicity further differentiated men in need of preconception care (p < .01). More than half of men in need of family planning reported none of the time current partner hormonal use (55%) or condom use (52%) during the past year. This study identified that many men in their mid-30s are in need of family planning or preconception care. PMID:25389215

  1. What are the causes for the spread of GLE parameters deduced from NM data?

    NASA Astrophysics Data System (ADS)

    Bütikofer, R.; Flückiger, E.

    2015-08-01

    Investigations have shown that the analysis results of ground level enhancements (GLEs) based on neutron monitor (NM) data for a selected event can differ considerably depending the procedure used. This may have significant consequences e.g. for the assessment of radiation doses at flight altitudes. The reasons for the spread of the GLE parameters deduced from NM data can be manifold and are at present unclear. They include differences in specific properties of the various analysis procedures (e.g. NM response functions, different ways in taking into account the dynamics of the Earth's magnetospheric field), different characterisations of the solar particle flux near Earth as well as the specific selection of NM stations used for the analysis. In the present paper we quantitatively investigate this problem for a time interval during the maximum phase of the GLE on 13 December 2006. We present and discuss the changes in the resulting GLE parameters when using different NM response functions, different model representations of the Earth's magnetospheric field as well as different assumptions for the solar particle spectrum and pitch angle distribution near Earth. The results of the study are expected to yield a basis for the reduction in the spread of the GLE parameters deduced from NM data.

  2. Systematics of the deduced fission barriers for the doubly even transactinium nuclei

    SciTech Connect

    Bhandari, B.S.; Bendardaf, Y.B. )

    1992-06-01

    The systematics of the fission barrier shapes of a total of 47 doubly even actinide and transactinide nuclei have been studied using the double-humped fission barrier model. The fission barrier has been parametrized in terms of four smoothly joined parabolic segments. The penetrabilities through such double-humped fission barriers have been calculated in the Wentzel-Kramers-Brillouin approximation, and the various fission half-lives have been determined using the formalism given earlier by Nix and Walker. The various parameters of such fission barriers have been deduced by requiring their simultaneous consistency with the various relevant fission observables, namely, the near-barrier fission cross sections, isomeric energies and isomeric half-lives, where available, and the ground-state spontaneous fission half-lives in the region 90{le}{ital Z}{le}98, and such model calculations with some further justifiable asssumptions have been extended to the region of the still heavier nuclei with {ital Z}{ge}100. The results of our systematic study of the heights of the inner and the outer barriers of the double-humped fission barriers corresponding to such doubly even nuclei suggest that while the height of the inner barrier remains approximately constant in the entire region of such nuclei, the deduced heights of the outer barrier decrease rather sharply and continuously with the increase in the value of the fissility parameter until one reaches the element Rf ({ital Z}=104).

  3. Near-Surface Flow Fields Deduced Using Correlation Tracking and Time-Distance Analysis

    NASA Technical Reports Server (NTRS)

    DeRosa, Marc; Duvall, T. L., Jr.; Toomre, Juri

    1999-01-01

    Near-photospheric flow fields on the Sun are deduced using two independent methods applied to the same time series of velocity images observed by SOI-MDI on SOHO. Differences in travel times between f modes entering and leaving each pixel measured using time-distance helioseismology are used to determine sites of supergranular outflows. Alternatively, correlation tracking analysis of mesogranular scales of motion applied to the same time series is used to deduce the near-surface flow field. These two approaches provide the means to assess the patterns and evolution of horizontal flows on supergranular scales even near disk center, which is not feasible with direct line-of-sight Doppler measurements. We find that the locations of the supergranular outflows seen in flow fields generated from correlation tracking coincide well with the locations of the outflows determined from the time-distance analysis, with a mean correlation coefficient after smoothing of bar-r(sub s) = 0.840. Near-surface velocity field measurements can used to study the evolution of the supergranular network, as merging and splitting events are observed to occur in these images. The data consist of one 2048-minute time series of high-resolution (0.6" pixels) line-of-sight velocity images taken by MDI on 1997 January 16-18 at a cadence of one minute.

  4. Wind speeds in two tornadic storms and a tornado, deduced from Doppler Spectra

    SciTech Connect

    Zrnic, D.; Istok, M.

    1980-12-01

    Doppler spectra of a tornado were collected with a radar having a large unambiguous velocity range, +- 91 m s/sup -1/. Thus for the first time a presentation of nonaliased spectra was possible, showing direct measurement of radial velocities. By fitting the tornado model spectrum to data, the radius of maximum winds and tornado center location are deduced. Tornado spectral signature is defined as a double peak, symmetric with respect to the mean wind spectrum. Histograms of maximum measured wind speeds (from spectrum skirts) for two tornadic storms are obtained, and the histograms of velocity difference (between the left and right spectrum skirt) suggest that smaller scale turbulence (<500 m) is principally responsible for spectrum broadness.

  5. Deducing fast electron density changes in randomly orientated uncrystallized biomolecules in a pump-probe experiment.

    PubMed

    Pande, K; Schwander, P; Schmidt, M; Saldin, D K

    2014-07-17

    We propose a method for deducing time-resolved structural changes in uncrystallized biomolecules in solution. The method relies on measuring the angular correlations of the intensities, when averaged over a large number of diffraction patterns from randomly oriented biomolecules in solution in a liquid solvent. The experiment is somewhat like a pump-probe version of an experiment on small angle X-ray scattering, except that the data expected by the algorithm are not just the radial variation of the averaged intensities. The differences of these correlation functions as measured from a photoexcited and dark structure enable the direct calculation of the difference electron density with a knowledge of only the dark structure. We exploit a linear relation we derive between the difference in these correlation functions and the difference electron density, applicable for small structural changes. PMID:24914159

  6. Behaviour of the Pleistocene marsupial lion deduced from claw marks in a southwestern Australian cave.

    PubMed

    Arman, Samuel D; Prideaux, Gavin J

    2016-01-01

    The marsupial lion, Thylacoleo carnifex, was the largest-ever marsupial carnivore, and is one of the most iconic extinct Australian vertebrates. With a highly-specialised dentition, powerful forelimbs and a robust build, its overall morphology is not approached by any other mammal. However, despite >150 years of attention, fundamental aspects of its biology remain unresolved. Here we analyse an assemblage of claw marks preserved on surfaces in a cave and deduce that they were generated by marsupial lions. The distribution and skewed size range of claw marks within the cave elucidate two key aspects of marsupial lion biology: they were excellent climbers and reared young in caves. Scrutiny of >10,000 co-located Pleistocene bones reveals few if any marsupial lion tooth marks, which dovetails with the morphology-based interpretation of the species as a flesh specialist. PMID:26876952

  7. Deducing ink thickness variations of fluorescent print by a spectral prediction model

    NASA Astrophysics Data System (ADS)

    Wang, Qingjuan; Zhang, Yixin; Tian, Dongwen

    2012-01-01

    In the color printing process, the thickness and uniformity of ink have a great affect on the color reproduction. The ink thickness uniformity is an important parameters of measuring the quality of printing. Based on the fluorescent additives may absorb ultraviolet light and exit blue light or visible light and by considering the expansion of the ink, optical properties of paper with fluorescent additives , the internal lateral spread of light in paper with fluorescent additives and the fluorescent Clapper-Yule spectral reflectance prediction model, we introduce two factor parameters which are the initial thickness of the inks and the factor of ink thickness variation. A model for deducing ink thickness variations of printing on the fluorescent substrate is developed by the least square method and the spectrum reflectance of prints which measures the ink thickness variations. The correctness of the conclusions are verified by experiment.

  8. Deducing fast electron density changes in randomly orientated uncrystallized biomolecules in a pump–probe experiment

    PubMed Central

    Pande, K.; Schwander, P.; Schmidt, M.; Saldin, D. K.

    2014-01-01

    We propose a method for deducing time-resolved structural changes in uncrystallized biomolecules in solution. The method relies on measuring the angular correlations of the intensities, when averaged over a large number of diffraction patterns from randomly oriented biomolecules in solution in a liquid solvent. The experiment is somewhat like a pump–probe version of an experiment on small angle X-ray scattering, except that the data expected by the algorithm are not just the radial variation of the averaged intensities. The differences of these correlation functions as measured from a photoexcited and dark structure enable the direct calculation of the difference electron density with a knowledge of only the dark structure. We exploit a linear relation we derive between the difference in these correlation functions and the difference electron density, applicable for small structural changes. PMID:24914159

  9. The work function of n-ZnO deduced from heterojunctions with Si prepared by ALD

    NASA Astrophysics Data System (ADS)

    Quemener, V.; Alnes, M.; Vines, L.; Rauwel, P.; Nilsen, O.; Fjellvåg, H.; Monakhov, E. V.; Svensson, B. G.

    2012-08-01

    Highly doped n-type ZnO films have been grown on n-type and p-type Si substrates by atomic layer deposition (ALD). Transmission electron microscopy shows columnar growth of the ZnO films with randomly oriented grains and a very thin interfacial layer of SiOx(x ⩽ 2) with a thickness below 0.4 nm to the Si substrate. Current-voltage and capacitance-voltage measurements performed at temperatures from 50 to 300 K reveal a strong rectifying behaviour on both types of substrates with an ideality factor close to unity between 180 and 280 K. Using the classical approach of thermionic emission, the barrier heights of the ZnO/n-Si and ZnO/p-Si junctions have been deduced and consistent values are obtained yielding a work function of n-type ZnO close to 4.65 eV.

  10. Distribution of atomic oxygen in the upper atmosphere deduced from Ogo 6 airglow observations.

    NASA Technical Reports Server (NTRS)

    Donahue, T. M.; Guenther, B.; Thomas, R. J.

    1973-01-01

    The atomic oxygen distribution as a function of altitude between 80 and 120 km and as a function of latitude has been deduced from Ogo 6 557.7-nm airglow photometer data obtained between August 1969 and April 1970. The results indicate that the density ranges from 15 to 50 billion per cu cm at 120 km; that there is a semiannual variation by a factor of 3 in the global average density near 100 km in phase with the satellite drag semiannual effect; and that large latitudinal variations occur with maximums between 40 and 60 deg in the winter hemisphere and sometimes deep minimums in the tropics. The implication of these results for meridional and vertical transport patterns is discussed.

  11. Oxygen plasma flow properties deduced from laser-induced fluorescence and probe measurements.

    PubMed

    Löhle, Stefan; Eichhorn, Christoph; Steinbeck, Andreas; Lein, Sebastian; Herdrich, Georg; Röser, Hans-Peter; Auweter-Kurtz, Monika

    2008-04-10

    Estimation of the local dissociation degree and the local mass-specific enthalpy of a pure oxygen plasma flow determined mainly from laser-induced fluorescence measurements are reported. Measurements have been conducted for several generator parameters in an inductively heated plasma wind tunnel. Additional probe measurements of total pressure together with the deduced translational temperature are used to estimate the local mass-specific enthalpy. For a reference condition, full dissociation has been measured. The measured translational temperature of atomic oxygen for this condition is T = 3500 K. Subsequently, the local mass-specific enthalpy has been derived using these local density and temperature measurements. For the reference condition the estimated value of h = 27 MJ/kg is in good agreement with the probe measurements and results from diode laser absorption spectroscopy. PMID:18404183

  12. Behaviour of the Pleistocene marsupial lion deduced from claw marks in a southwestern Australian cave

    PubMed Central

    Arman, Samuel D.; Prideaux, Gavin J.

    2016-01-01

    The marsupial lion, Thylacoleo carnifex, was the largest-ever marsupial carnivore, and is one of the most iconic extinct Australian vertebrates. With a highly-specialised dentition, powerful forelimbs and a robust build, its overall morphology is not approached by any other mammal. However, despite >150 years of attention, fundamental aspects of its biology remain unresolved. Here we analyse an assemblage of claw marks preserved on surfaces in a cave and deduce that they were generated by marsupial lions. The distribution and skewed size range of claw marks within the cave elucidate two key aspects of marsupial lion biology: they were excellent climbers and reared young in caves. Scrutiny of >10,000 co-located Pleistocene bones reveals few if any marsupial lion tooth marks, which dovetails with the morphology-based interpretation of the species as a flesh specialist. PMID:26876952

  13. Fission fragment mass yield deduced from density distribution in the pre-scission configuration

    NASA Astrophysics Data System (ADS)

    Warda, M.; Zdeb, A.

    2015-11-01

    Static self-consistent methods usually allow one to determine the most probable fission fragments mass asymmetry. We have applied random neck rupture mechanism to the nuclei in the configuration at the end of fission paths. Fission fragment mass distributions have been deduced from the pre-scission nuclear density distribution obtained from the self-consistent calculations. Potential energy surfaces as well as nuclear shapes have been calculated in the fully microscopic theory, namely the constrained Hartree-Fock-Bogoliubov model with the effective Gogny D1S density-dependent interaction. The method has been applied for analysis of fission of {}{256,258}Fm, 252Cf and 180Hg and compared with the experimental data.

  14. A major protein precursor of zebra mussel (Dreissena polymorpha) byssus: deduced sequence and significance.

    PubMed

    Anderson, K E; Waite, J H

    1998-04-01

    The zebra mussel is a nonindigenous invader of North American lakes and rivers and one of the few freshwater bivalve molluscs having a byssus--a sclerotized organ used by the mussel for opportunistic attachment to hard surfaces. We have sequenced a foot-specific cDNA whose composite protein sequence was deduced from a series of overlapping but occasionally nonidentical cDNA fragments. The overall deduced sequence matches tryptic peptides from a major byssal precursor protein--Dreissena polymorpha foot protein 1 (Dpfp1). The calculated mass of Dpfp1 is 49 kDa; but this is known to be extensively hydroxylated and O-glycosylated during maturation. Purified native Dpfp1 analyzed using matrix-assisted laser-desorption ionization mass spectrometry with time-of-flight indicates that the protein occurs as at least two size variants with masses of 48.6 and 54.5 kDa. In all probability, the sequence variants reported in this study are related to the larger mass variant. Dpfp1 has a block copolymer-like structure defined by two consensus motifs that are sharply segregated into domains. The N-terminal side of Dpfp1 has 22 tandem repeats of a heptapeptide consensus (P-[V/E]-Y-P-[T/S/delta]-[K/Q]-X); the C-terminal side has 16 repeats of a tridecapeptide motif (K-P-G-P-Y-D-Y-D-G-P-Y-D-K). Both consensus repeats are unique, with some limited homology to other proteins functioning in tension: marine mussel adhesives, plant extensins, titin, and trematode eggshell precursors. PMID:9604314

  15. Deducing the 237U(n,f) cross-section using the Surrogate Ratio Method

    SciTech Connect

    Burke, J T; Bernstein, L A; Escher, J; Ahle, L; Church, J A; Dietrich, F S; Moody, K J; Norman, E B; Phair, L; Fallon, P; Clark, R M; Deleplanque, M A; Descovich, M; Cromaz, M; Lee, I Y; Macchiavelli, A O; McMahan, M A; Moretto, L G; Rodriguez-Vieitez, E; Stephens, F S; Ai, H; Beausang, C; Cridder, B

    2005-12-29

    The authors have deduced the cross section for {sup 237}U(n,f) over an equivalent neutron energy range from 0 to 20 MeV using the Surrogate Ratio method. A 55 MeV {sup 4}He beam from the 88 Inch Cyclotron at Lawrence Berkeley National Laboratory was used to induce fission in the following reactions: {sup 238}U({alpha},{alpha}{prime}f) and {sup 236}U({alpha},{alpha}{prime}f). The {sup 238}U reaction was a surrogate for {sup 237}U(n,f) and the {sup 236}U reaction was used as a surrogate for {sup 235}U(n,f). Scattered alpha particles were detected in a fully depleted segmented silicon telescope array (STARS) over an angle range of 35{sup o} to 60{sup o} with respect to the beam axis. The fission fragments were detected in a third independent silicon detector located at backward angles between 106{sup o} and 131{sup o}.

  16. Stratospheric aerosol acidity, density, and refractive index deduced from SAGE 2 and NMC temperature data

    NASA Technical Reports Server (NTRS)

    Yue, G. K.; Poole, L. R.; Wang, P.-H.; Chiou, E. W.

    1994-01-01

    Water vapor concentrations obtained by the Stratospheric Aerosol and Gas Experiment 2 (SAGE 2) and collocated temperatures provided by the National Meteorological Center (NMC) from 1986 to 1990 are used to deduce seasonally and zonally averaged acidity, density, and refractive index of stratospheric aerosols. It is found that the weight percentage of sulfuric acid in the aerosols increases from about 60 just above the tropopause to about 86 at 35 km. The density increases from about 1.55 to 1.85 g/cu cm between the same altitude limits. Some seasonal variations of composition and density are evident at high latitudes. The refractive indices at 1.02, 0.694, and 0.532 micrometers increase, respectively, from about 1.425, 1.430, and 1.435 just above the tropopause to about 1.445, 1.455, and 1.458 at altitudes above 27 km, depending on the season and latitude. The aerosol properties presented can be used in models to study the effectiveness of heterogeneous chemistry, the mass loading of stratospheric aerosols, and the extinction and backscatter of aerosols at different wavelengths. Computed aerosol surface areas, rate coefficients for the heterogeneous reaction ClONO2 + H2O yields HOCl + HNO3 and aerosol mass concentrations before and after the Pinatubo eruption in June 1991 are shown as sample applications.

  17. Thin cirrus clouds - Seasonal distribution over oceans deduced from Nimbus-4 IRIS

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Fraser, R. S.; Dalu, G.; Wu, Man-Li C.; Curran, R. J.

    1988-01-01

    Spectral differences in the extinction of the 10.8- and 12.6-micron bands of the IR window region, due to optically thin clouds, were found in the measurements made by both an airborne broadband IR radiometer and the IR interferometer spectrometer (IRIS) aboard the Nimbus-4 satellite; the extinction at 12.6 microns was significantly larger than that at 10.8 microns; both water and ice particles in the clouds can account for such spectral difference in extinction. Multiple scattering radiative transfer calculations of IRIS data revealed this spectral feature about 100 to 20 km away from the high-altitude cold clouds; it is assumed that this feature is related to the spreading of cirrus clouds. Based on this assumption, mean seasonal maps of the distribution of thin cirrus clouds over the oceans were deduced from the IRIS data. The maps show that such clouds are often present over the convectively active areas, such as ITCZ, SPCZ, and the Bay of Bengal during the summer monsoon.

  18. Chemical composition of the Howardite Parent Body deduced from Kapoeta primary 'mafic' magmas

    NASA Technical Reports Server (NTRS)

    Smith, M. R.; Schmitt, R. A.

    1982-01-01

    Chemical data are presented for three 'mafic' clasts extracted from the Kapoeta howardite. Bulk compositions and petrologic observations suggest that two of these lithic clasts represent olivine-plagioclase bearing orthopyroxenites. Chondrite-relative refractory large ion lithophile abundances of two of the clasts are inferred to represent primary Mg-rich magmas produced by extensive (greater than about 70%) partial melting of a source composition indistinguishable from the silicate fraction of average CH-CL ordinary chondrites, with the exception of the depletion of the alkalis Na and K by a factor of 13 + or - 1 in the source composition. A metal-free and volatile depleted Kapoeta Parent Body (KPB) is subsequently deduced and is shown to compare very well with other similarly derived Achondrite Parent Body and Howardite Parent Body estimates but not to parent body estimates derived from inferences based on eucrite phase equilibrium studies. Other implications suggest that the KPB is heterogeneous with respect to Fe/Mg ratios.

  19. Epitopes of human testis-specific lactate dehydrogenase deduced from a cDNA sequence

    SciTech Connect

    Millan, J.L.; Driscoll, C.E.; LeVan, K.M.; Goldberg, E.

    1987-08-01

    The sequence and structure of human testis-specific L-lactate dehydrogenase (LDHC/sub 4/, LDHX; (L)-lactate:NAD/sup +/ oxidoreductase, EC 1.1.1.27) has been derived from analysis of a complementary DNA (cDNA) clone comprising the complete protein coding region of the enzyme. From the deduced amino acid sequence, human LDHC/sub 4/ is as different from rodent LDHC/sub 4/ (73% homology) as it is from human LDHA/sub 4/ (76% homology) and porcine LDHB/sub 4/ (68% homology). Subunit homologies are consistent with the conclusion that the LDHC gene arose by at least two independent duplication events. Furthermore, the lower degree of homology between mouse and human LDHC/sub 4/ and the appearance of this isozyme late in evolution suggests a higher rate of mutation in the mammalian LDHC genes than in the LDHA and -B genes. Comparison of exposed amino acid residues of discrete anti-genic determinants of mouse and human LDHC/sub 4/ reveals significant differences. Knowledge of the human LDHC/sub 4/ sequence will help design human-specific peptides useful in the development of a contraceptive vaccine.

  20. The Seismic risk perception in Italy deduced by a statistical sample

    NASA Astrophysics Data System (ADS)

    Crescimbene, Massimo; La Longa, Federica; Camassi, Romano; Pino, Nicola Alessandro; Pessina, Vera; Peruzza, Laura; Cerbara, Loredana; Crescimbene, Cristiana

    2015-04-01

    In 2014 EGU Assembly we presented the results of a web a survey on the perception of seismic risk in Italy. The data were derived from over 8,500 questionnaires coming from all Italian regions. Our questionnaire was built by using the semantic differential method (Osgood et al. 1957) with a seven points Likert scale. The questionnaire is inspired the main theoretical approaches of risk perception (psychometric paradigm, cultural theory, etc.) .The results were promising and seem to clearly indicate an underestimation of seismic risk by the italian population. Based on these promising results, the DPC has funded our research for the second year. In 2015 EGU Assembly we present the results of a new survey deduced by an italian statistical sample. The importance of statistical significance at national scale was also suggested by ISTAT (Italian Statistic Institute), considering the study as of national interest, accepted the "project on the perception of seismic risk" as a pilot study inside the National Statistical System (SISTAN), encouraging our RU to proceed in this direction. The survey was conducted by a company specialised in population surveys using the CATI method (computer assisted telephone interview). Preliminary results will be discussed. The statistical support was provided by the research partner CNR-IRPPS. This research is funded by Italian Civil Protection Department (DPC).

  1. Rates of intra- and intermolecular electron transfers in hydrogenase deduced from steady-state activity measurements.

    PubMed

    Dementin, Sébastien; Burlat, Bénédicte; Fourmond, Vincent; Leroux, Fanny; Liebgott, Pierre-Pol; Abou Hamdan, Abbas; Léger, Christophe; Rousset, Marc; Guigliarelli, Bruno; Bertrand, Patrick

    2011-07-01

    Electrons are transferred over long distances along chains of FeS clusters in hydrogenases, mitochondrial complexes, and many other respiratory enzymes. It is usually presumed that electron transfer is fast in these systems, despite the fact that there has been no direct measurement of rates of FeS-to-FeS electron transfer in any respiratory enzyme. In this context, we propose and apply to NiFe hydrogenase an original strategy that consists of quantitatively interpreting the variations of steady-state activity that result from changing the nature of the FeS clusters which connect the active site to the redox partner, and/or the nature of the redox partner. Rates of intra- and intermolecular electron transfer are deduced from such large data sets. The mutation-induced variations of electron transfer rates cannot be explained by changes in intercenter distances and reduction potentials. This establishes that FeS-to-FeS rate constants are extremely sensitive to the nature and coordination of the centers. PMID:21615141

  2. Latitudinal distribution of solar wind as deduced from Lyman alpha measurements - an improved method

    NASA Astrophysics Data System (ADS)

    Summanen, T.; Lallement, R.; Bertaux, J. L.; Kyrola, E.

    1993-08-01

    In this work we examine the possibility of deducing the latitudinal distribution of the solar ionization rate using Prognoz 6 Lyman-alpha data in a more general and flexible way than previously examined. Using a so-called hot model for the hydrogen distribution and the optically thin model for the resonance scattering, theoretical Lyman-alpha intensity for the interstellar hydrogen is calculated and compared with the intensity data measured by Prognoz 6. Varying the latitudinal dependence of the ionization rate, the distributions which produce the best fit with the data are analyzed for four different measuring sessions. As a result, we get four ionization rate distributions that have two common features. The ionization rate is enhanced near the solar equator, and large broad plateaus exist around heliographic latitudes +/- 30 to +/- 70 deg. The latitudinal distribution of the average ionization rate about the solar minimum deviates clearly from the spherically symmetric and sinusoidally with the latitude-varying models used so far. The growth of the solar wind mass flux from the solar polar areas toward the equator corresponds to the earlier results found from Lyman-alpha measurements.

  3. Relations between aliphatics and silicate components in 12 stratospheric particles deduced from vibrational spectroscopy

    SciTech Connect

    Merouane, S.; Djouadi, Z.; Le Sergeant d'Hendecourt, L.

    2014-01-10

    Interplanetary dust particles (IDPs) are among the most pristine extraterrestrial samples available in the laboratory for analyses with moderate to high spatial- and spectral-resolution spectroscopic techniques. Their composition can provide precious information on the early stages of the solar nebula as well as on the processes on the surfaces of different small bodies in the solar system from which IDPs originate. In this work, we have analyzed six anhydrous IDPs and six stratospheric particles possibly of cosmic origin through infrared (IR) and Raman micro-spectroscopy to study and investigate their silicate and organic components. We find that the length/ramification of the aliphatic organics given by the CH{sub 2}/CH{sub 3} ratios in the IDPs is closely linked to the silicate family (pyroxene or olivine) present in the samples. Both IR and Raman data suggest that this relation is not correlated with either aqueous (as evidenced by the absence of aqueous related minerals) or thermal processes (as deduced from Raman measurements). Therefore, this observation might be related to the initial path of formation of the organics on the silicate surfaces, thus tracing a possible catalytic role that silicates would play in the formation and/or ramification of organic matter in the primitive nebula.

  4. Using Bayesian Evidence to Deduce the Dust-Attenuation Law at High Redshift

    NASA Astrophysics Data System (ADS)

    Salmon, Brett W.; Papovich, Casey J.; Finkelstein, Steven L.; Closson Ferguson, Henry; Long, James; CANDELS

    2016-01-01

    Although the nature of dust attenuation affects nearly all aspects of galaxy evolution, very little is known about the form of the dust-attenuation law in the distant Universe. Dust enshrouds and obscures UV star formation, convoluting our understanding of galaxy evolution at high redshift. Recent literature has recognized how the inferred physical properties of distant galaxies can be influenced by the non-universality of their attenuation curve shape. In this talk, I will present a Bayesian method to quantitatively constrain the dust-attenuation curve in high-redshift star-forming galaxies. This method is tested on galaxies at z~2 where we have CANDELS UV-to-optical photometry and Spitzer/Herschel IR luminosities. We find that the dust law implied from using only UV/optical data to calculate the full posterior probability densities supports the observed IR luminosities as predicted by that dust law. This method shows promise to deduce the shape of the attenuation curve at higher redshifts (z>4), as supported by our experiments using mock data from a semi-analytic model with qualities like those of the CANDELS GOODS fields.

  5. Relative stability and magic numbers of nuclei deduced from behavior of cluster emission half-lives

    NASA Astrophysics Data System (ADS)

    Ismail, M.; Seif, W. M.; Abdurrahman, A.

    2016-08-01

    We calculated the half-life times (Tc) of the 14C, 20O, 20Ne, and 24Ne cluster emissions from heavy and superheavy nuclei. The variation of Tc with the neutron and proton numbers of daughter nuclei is studied to determine the minima in log10Tc at each neutron number for different daughter isotones. We found that each minimum for a given isotone corresponds to neutron magicity already indicated by other approaches. The proton numbers at neutron magic numbers were found to be also proton magic numbers or differ slightly from them. We arranged the different isotones at each neutron magic number according to their stability in the sense that the more stable daughter isotone corresponds to the lowest value of log10Tc . The magic neutron numbers predicted by the present study are N =126 , 148, 152, 154, 160, 162, 172, 176, 178, 180, 182, 184, and 200. The predicted magic proton numbers are Z =82 , 98, 100 102, 106, 108, 114, and 116. The values of N and Z mentioned above agree with magic numbers deduced in other studies.

  6. Deducing the 237U(n,f) cross-section using the Surrogate Ratio Method

    SciTech Connect

    Burke, J T; Bernstein, L A; Escher, J; Ahle, L; Church, J A; Dietrich, F; Moody, K J; Norman, E B; Phair, L W; Fallon, P; Clark, R; Delaplanque, M; Descovich, M; Cromaz, M; Lee, I Y; Macchiavelli, A O; McMahan, M A; Moretto, L G; Rodriguez-Vieitez, E; Stephens, F S

    2005-08-16

    The authors have deduced the {sup 237}U(n,f) cross-section over an equivalent neutron energy range of 0 to 20 MeV using the Surrogate Ratio method. A 55 MeV {sup 4}He{sup 2+} beam from the 88 Inch Cyclotron at Lawrence Berkeley National Laboratory was used to induce fission in the following reactions {sup 238}U({alpha},{alpha}'f) and {sup 236}U({alpha},{alpha}'f). The {sup 238}U reaction was a surrogate for {sup 237}U(n,f) and the {sup 236}U reaction was used as a surrogate for {sup 235}U(n,f). The energies of the scattered alpha particles were detected in a fully depleted segmented silicon telescope array (STARS) over an angle range of 35{sup o} to 60{sup o} with respect to the beam axis. The fission fragments were detected in a third independent silicon detector located at backward angles between 106{sup o} to 131{sup o}.

  7. Relations between Aliphatics and Silicate Components in 12 Stratospheric Particles Deduced from Vibrational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Merouane, S.; Djouadi, Z.; Le Sergeant d'Hendecourt, L.

    2014-01-01

    Interplanetary dust particles (IDPs) are among the most pristine extraterrestrial samples available in the laboratory for analyses with moderate to high spatial- and spectral-resolution spectroscopic techniques. Their composition can provide precious information on the early stages of the solar nebula as well as on the processes on the surfaces of different small bodies in the solar system from which IDPs originate. In this work, we have analyzed six anhydrous IDPs and six stratospheric particles possibly of cosmic origin through infrared (IR) and Raman micro-spectroscopy to study and investigate their silicate and organic components. We find that the length/ramification of the aliphatic organics given by the CH2/CH3 ratios in the IDPs is closely linked to the silicate family (pyroxene or olivine) present in the samples. Both IR and Raman data suggest that this relation is not correlated with either aqueous (as evidenced by the absence of aqueous related minerals) or thermal processes (as deduced from Raman measurements). Therefore, this observation might be related to the initial path of formation of the organics on the silicate surfaces, thus tracing a possible catalytic role that silicates would play in the formation and/or ramification of organic matter in the primitive nebula.

  8. Creep Along the North Anatolian Fault at Ismetpasa (Western Turkey) Deduced From InSAR

    NASA Astrophysics Data System (ADS)

    Cakir, Z.; Ergintav, S.; Akoglu, A. M.; Belabbes, S.; Meghraoui, M.

    2004-12-01

    Although creeping along the North Anatolian Fault (NAF) at Ismetpasa (Turkey) was discovered some thirty years ago, about a decade after the first observation of the phenomenon along the San Andreas Fault in California, little is known about its extent and rate. In order to reveal its three dimensional nature and rupture characteristics, we use Synthetic Aperture Radar Interferometry (InSAR) and dislocations on rectangular faults in elastic half space. Interferograms with temporal baselines ranging between 1.25 and 5 years show that creeping starts at the western termination of the 1943 (Mw=7.6) earthquake rupture and continues about 70-km to the west overlapping with the eastern part of the 185-km-long rupture of the 1944 (Mw=7.3) earthquake. Maximum creep rate is 10 mm/year approximately in the mid point of the creeping part of the rupture segment diminishing gradually towards the edges. Near Ismetpasa, InSAR data yield 7.7 mm/year of creep rate, consistent with those deduced from instrumental (triangulation and creepmeters) measurements (i.e. 9 mm/year). Modeling of the InSAR and GPS data suggests that the fault creep occurs most probably at a shallow depth (0-7 km). InSAR data do not support the previous claims of creep events triggered by the 1999 Izmit earthquake.

  9. Possibility to Deduce the Emission Time Sequence of Neutrons and Protons from the Neutron-Proton Correlation Function

    SciTech Connect

    Ghetti, R.; Helgesson, J.; Colonna, N.; Jakobsson, B.; Anzalone, A.; Bellini, V.; Carlen, L.; Cavallaro, S.; Celano, L.; De Filippo, E.

    2001-09-03

    Experimental information has been derived from the neutron-proton correlation function in order to deduce the time sequence of neutrons and protons emitted at 45{sup o} in the E/A=45 MeV {sup 58}Ni+{sup 27}Al reaction.

  10. Deducing growth mechanisms for minerals from the shapes of crystal size distributions

    USGS Publications Warehouse

    Eberl, D.D.; Drits, V.A.; Srodon, J.

    1998-01-01

    Crystal size distributions (CSDs) of natural and synthetic samples are observed to have several distinct and different shapes. We have simulated these CSDs using three simple equations: the Law of Proportionate Effect (LPE), a mass balance equation, and equations for Ostwald ripening. The following crystal growth mechanisms are simulated using these equations and their modifications: (1) continuous nucleation and growth in an open system, during which crystals nucleate at either a constant, decaying, or accelerating nucleation rate, and then grow according to the LPE; (2) surface-controlled growth in an open system, during which crystals grow with an essentially unlimited supply of nutrients according to the LPE; (3) supply-controlled growth in an open system, during which crystals grow with a specified, limited supply of nutrients according to the LPE; (4) supply- or surface-controlled Ostwald ripening in a closed system, during which the relative rate of crystal dissolution and growth is controlled by differences in specific surface area and by diffusion rate; and (5) supply-controlled random ripening in a closed system, during which the rate of crystal dissolution and growth is random with respect to specific surface area. Each of these mechanisms affects the shapes of CSDs. For example, mechanism (1) above with a constant nucleation rate yields asymptotically-shaped CSDs for which the variance of the natural logarithms of the crystal sizes (??2) increases exponentially with the mean of the natural logarithms of the sizes (??). Mechanism (2) yields lognormally-shaped CSDs, for which ??2 increases linearly with ??, whereas mechanisms (3) and (5) do not change the shapes of CSDs, with ??2 remaining constant with increasing ??. During supply-controlled Ostwald ripening (4), initial lognormally-shaped CSDs become more symmetric, with ??2 decreasing with increasing ??. Thus, crystal growth mechanisms often can be deduced by noting trends in ?? versus ??2 of CSDs for

  11. Spokes in Saturn's B Ring: dynamical and physical properties deduced from Voyager Saturn Ring images

    SciTech Connect

    Eplee, R.E.

    1987-01-01

    This project studied dynamical and physical properties of spokes as deduced from Voyage Saturn ring images. Analysis of the orbital motion of two dynamically-anomalous spokes, in particular, set limits on the charge-to-mass ratios of spoke particles at various times during their dynamical evolution. These two spokes have charge-to-mass of at least -60 +/- 3 C kg/sup -1/ while corotating with Saturn, and charge-to-mass ratios of no more than -22 +/- 2 C kg/sup -1/ while orbiting Saturn at Keplerian velocities. Additionally, charge decay on the grains of these spokes, caused by solar UV photoemission, allowed a lower limit of 0.10 +/- 0.03 ..mu..m to be placed on the range of radii for spoke particles. In a study of spoke photometry, a single-scattering analysis of the 0.470-..mu..m phase function for spokes has set a mean radius for the dominant scatterers (at this wavelength) of 0.22 +/- 0.02 /sup +/m. The transport of angular momentum within the rings due to the radial motion of spoke grains is shown to be the most-significant effect of spoke activity on the dynamical evolution of the B Ring, as was predicted by Goertz et al. (1986, Nature 320, 141-143). The radial mass-transport velocity due to highly-charged spokes is -1 x 10/sup -9/m s/sup -1/. The subsequent spreading time for the B Ring is 600 million years, which is significantly less than the 4.6 billion-year age of the solar system.

  12. Zonal currents in the F region deduced from Swarm constellation measurements

    NASA Astrophysics Data System (ADS)

    Lühr, Hermann; Kervalishvili, Guram; Rauberg, Jan; Stolle, Claudia

    2016-01-01

    The Swarm constellation has been used to estimate zonal currents in the topside F region ionosphere at about 500 km. Near-simultaneous magnetic field measurements from two altitudes but the same meridian are used for the current density calculations. We consider the period 15 February to 23 June 2014 for deriving a full 24 h local time coverage of the latitudinal distribution over ±50° in magnetic latitude. Intervals with close orbital phasing at the two heights are considered, which repeat every 6 days. From such days seven successive orbits are used where the epochs of equator crossings differ by less than 2 min. Deduced current densities are predominantly eastward (about 20 nA/m2) on the dayside and westward (about 10 nA/m2) on the nightside. A number of different drivers contribute to the observed total current. We identified the gravity-driven eastward current as the most prominent at low latitudes. Eastward currents in the Northern Hemisphere are clearly stronger than in the south. This is attributed to the proximity of our study period to June solstice, when the solar radiation is stronger in the north. In addition, interhemispheric winds from the Northern (summer) to the Southern (winter) Hemisphere contribute. They cause eastward currents in the north and westward in the south. We find a relatively large variability of the zonal currents both in space and time. The standard deviation is at least twice as large as the mean value of current density. This large variability is suggested to be related to gravity wave forcing from below.

  13. The radiation budget of a Cirrus layer deduced from simultaneous aircraft observations and model calculations

    NASA Technical Reports Server (NTRS)

    Ackerman, Thomas P.; Kinne, Stefan A.; Heymsfield, Andrew J.; Valero, Francisco P. J.

    1990-01-01

    Several aircraft were employed during the FIRE Cirrus IFO in order to make nearly simultaneous observations of cloud properties and fluxes. A segment of the flight data collected on 28 October 1988 during which the NASA Ames ER-2 overflew the NCAR King Air was analyzed. The ER-2 flew at high altitude making observations of visible and infrared radiances and infrared flux and cloud height and thickness. During this segment, the King Air flew just above the cloud base making observations of ice crystal size and shape, local meteorological variables, and infrared fluxes. While the two aircraft did not collect data exactly coincident in space and time, they did make observations within a few minutes of each other. For this case study, the infrared radiation balance of the cirrus layer is of primary concern. Observations of the upwelling 10 micron radiance, made from the ER-2, can be used to deduce the 10 micron optical depth of the layer. The upwelling broadband infrared flux is also measured from the ER-2. At the same time, the upwelling and downwelling infrared flux at the cloud base is obtained from the King Air measurements. Information on cloud microphysics is also available from the King Air. Using this data in conjunction with atmospheric temperature and humidity profiles from local radiosondes, the necessary inputs for an infrared radiative transfer model can be developed. Infrared radiative transfer calculations are performed with a multispectral two-stream model. The model fluxes at the cloud base and at 19 km are then compared with the aircraft observations to determine whether the model is performing well. Cloud layer heating rates can then be computed from the radiation exchange.

  14. Deducing Electronic Unit Internal Response During a Vibration Test Using a Lumped Parameter Modeling Approach

    NASA Technical Reports Server (NTRS)

    Van Dyke, Michael B.

    2014-01-01

    During random vibration testing of electronic boxes there is often a desire to know the dynamic response of certain internal printed wiring boards (PWBs) for the purpose of monitoring the response of sensitive hardware or for post-test forensic analysis in support of anomaly investigation. Due to restrictions on internally mounted accelerometers for most flight hardware there is usually no means to empirically observe the internal dynamics of the unit, so one must resort to crude and highly uncertain approximations. One common practice is to apply Miles Equation, which does not account for the coupled response of the board in the chassis, resulting in significant over- or under-prediction. This paper explores the application of simple multiple-degree-of-freedom lumped parameter modeling to predict the coupled random vibration response of the PWBs in their fundamental modes of vibration. A simple tool using this approach could be used during or following a random vibration test to interpret vibration test data from a single external chassis measurement to deduce internal board dynamics by means of a rapid correlation analysis. Such a tool might also be useful in early design stages as a supplemental analysis to a more detailed finite element analysis to quickly prototype and analyze the dynamics of various design iterations. After developing the theoretical basis, a lumped parameter modeling approach is applied to an electronic unit for which both external and internal test vibration response measurements are available for direct comparison. Reasonable correlation of the results demonstrates the potential viability of such an approach. Further development of the preliminary approach presented in this paper will involve correlation with detailed finite element models and additional relevant test data.

  15. A novel computational framework for deducing muscle synergies from experimental joint moments

    PubMed Central

    Gopalakrishnan, Anantharaman; Modenese, Luca; Phillips, Andrew T. M.

    2014-01-01

    Prior experimental studies have hypothesized the existence of a “muscle synergy” based control scheme for producing limb movements and locomotion in vertebrates. Such synergies have been suggested to consist of fixed muscle grouping schemes with the co-activation of all muscles in a synergy resulting in limb movement. Quantitative representations of these groupings (termed muscle weightings) and their control signals (termed synergy controls) have traditionally been derived by the factorization of experimentally measured EMG. This study presents a novel approach for deducing these weightings and controls from inverse dynamic joint moments that are computed from an alternative set of experimental measurements—movement kinematics and kinetics. This technique was applied to joint moments for healthy human walking at 0.7 and 1.7 m/s, and two sets of “simulated” synergies were computed based on two different criteria (1) synergies were required to minimize errors between experimental and simulated joint moments in a musculoskeletal model (pure-synergy solution) (2) along with minimizing joint moment errors, synergies also minimized muscle activation levels (optimal-synergy solution). On comparing the two solutions, it was observed that the introduction of optimality requirements (optimal-synergy) to a control strategy solely aimed at reproducing the joint moments (pure-synergy) did not necessitate major changes in the muscle grouping within synergies or the temporal profiles of synergy control signals. Synergies from both the simulated solutions exhibited many similarities to EMG derived synergies from a previously published study, thus implying that the analysis of the two different types of experimental data reveals similar, underlying synergy structures. PMID:25520645

  16. Traveling Wave Packets of Total Electron Content Disturbances As Deduced From Global GPS Network Data

    NASA Astrophysics Data System (ADS)

    Afraimovich, E.; Lesyuta, O.; Lipko, Yu.; Perevalova, N.; Voyeikov, S.; Vodyannikov, V.; Yakovets, A.; Jacobi, Ch.

    This report discusses the experimental research results on the morphology and physi- cal origin of total electron content (TEC) pulsations as measured using the data from the global GPS network. Periodic electron density oscillations of the type of wave packets were investigated previously in terms of the hypothesis of their association with geomagnetic field (GP) pulsations. The greater part of evidence of the association between GP ad periodic electron density oscillations in the ionosphere was obtained by recording the frequency Doppler shift if the ionosphere-reflected radio signal and TEC variations measured using signals from geostationary satellites. However, many years of investigations have not yet provided thorough insight into the mechanisms ac- counting for the linkage between GP and ionospheric variations. One reason for that is the difficulty associated with obtaining statistically significant sets of experimental data. The use of the international ground-based network of two-frequency receivers of the navigation GPS system which comprised no less than 900 site as of August 2001 and is currently placing the data on the Internet, opens up a new era of a global, con- tinuous and fully computerized monitoring of ionospheric disturbances of a different class. This report presents a global morphology of TEC pulsations for 50 days with a different level of geomagnetic activity and the number of stations of the global GPS network from 100 to 300. A total number of the "receiver - GPS satellites" radio paths used in the analysis is about 500,000. Quasi-periodic TEC variations in the range of periods from 10 to 20 min are investigated, which is dictated by the fact that the data from the global GPS network are placed on the Internet with a standard temporal res- olution of 30 s. Most often, the observed TEC pulsations represent wave packets with a duration on the order of 1 hour. It was found that such TEC pulsations are a rela- tively rare event and are

  17. The residual interaction of bound nucleons-two-nucleon matrix elements deduced from transfer experiments

    NASA Astrophysics Data System (ADS)

    Daehnick, W. W.

    1983-07-01

    Matrix elements for the effective two-nucleon interaction have been deduced from the population of multiplets near closed shells as observed in direct transfer reactions. In the evaluation, the limited purity of such multiples was taken into consideration, typically by weighting the observed fractions of the two-nucleon configurations by their spectroscopic strenghts and by using the resulting energy centroids. In a few cases, off-diagonal matrix elements are available from empirical wave funcitons. The systematic errors for particle-particle matrix elements extracted directly and those obtained from Pandya transformations were found to go in opposite directions. In some cases, this feautre of the empirical mehtod could be used to suggest upper and lower “bounds” for the extracted matrix elements. Diagonal matrix elements for the empirical residual interaction show a number of features suggestive of an underlying simplicity in the interaction of bound nucleons. Within experimental uncertainties (of about 10% for T=0 matrix elements) the monopole parts of the matrix elements are fit well with a simple A-0.75 dependence, and the data available to date do not reveal any significant monopole dependence on the quantum numbers of the interacting nucleons. The usefulness of scaling is suggested. Generally, diagonal matrix elements EJ( j1, j2) normalized by the extracted A-dependent monopole strength agree within expected experimental uncertainties whether derived from particle-particle or particle-hole multiples and whether extracted from the beginning or the end of a major shell. For values J≠0, the diagonal EJ( j2) matrix elements seem to follow two universal functions which depend on the semi-classical coupling angles θ 12, but are otherwise independent on j. For j1≠ j2 several “typical” functions ƒ(θ 12) can be constructed which fit subsets of the data and differ in a predictable way. The general features of the bound-nucleon interaction appear

  18. Tropospheric CO vertical profiles deduced from total columns using data assimilation: methodology and validation

    NASA Astrophysics Data System (ADS)

    El Amraoui, L.; Attié, J.-L.; Ricaud, P.; Lahoz, W. A.; Piacentini, A.; Peuch, V.-H.; Warner, J. X.; Abida, R.; Barré, J.

    2013-07-01

    This paper presents a validation of a method to derive the vertical profile of carbon monoxide (CO) from its total column using data assimilation. The main motivation of this study is twofold. First, to deduce both the vertical CO profiles and the assimilated CO fields with good confidence. Second, for chemical species that can be measured only as the total column, this method provides an attractive alternative for estimating their vertical profiles in the troposphere. We choose version 3 (V3) of MOPITT CO total columns to validate the proposed method. MOPITT has the advantage of providing both the vertical profiles and the total columns of CO. Furthermore, this version has been extensively validated by comparison with many independent datasets, and has been used in many scientific studies. The first step of the paper consists in the specification of the observation errors based on the Chi-square (χ2) test. The observations have been binned according to day, night, land and sea (LAND_DAY, LAND_NIGHT and SEA, respectively). The respective optimal observation error values for which the χ2 metric is the closest to 1 are: 7%, 8% and 11% for SEA, LAND_DAY and LAND_NIGHT, respectively. In a second step, the CO total column, with its specified errors, is used within the assimilation system to estimate the vertical profiles. These are validated by comparison with vertical profiles of MOPITT V3 retrievals at global and regional scales. Generally, both datasets show similar patterns and good agreement at both global and regional scales. Nevertheless, the total column analyses (TOTCOL_ANALYSES) slightly overestimate CO concentrations compared to MOPITT observations. In a third step, vertical profiles calculated from TOTCOL_ANALYSES have been compared to those calculated from the assimilation of MOPITT V3 vertical profiles (PROFILE_ANALYSES). Both datasets shows very good agreement, but TOTCOL_ANALYSES tend to slightly overestimate CO concentrations. The mean bias between

  19. Active deformation processes of the Northern Caucasus deduced from the GPS observations

    NASA Astrophysics Data System (ADS)

    Milyukov, Vadim; Mironov, Alexey; Rogozhin, Eugeny; Steblov, Grigory; Gabsatarov, Yury

    2015-04-01

    The Northern Caucasus, as a part of the Alpine-Himalayan mobile belt, is a zone of complex tectonics associated with the interaction of the two major tectonic plates, Arabian and Eurasian. The first GPS study of the contemporary geodynamics of the Caucasus mountain system were launched in the early 1990s in the framework of the Russia-US joint project. Since 2005 observations of the modern tectonic motion of the Northern Caucasus are carried out using the continuous GPS network. This network encompasses the territory of three Northern Caucasian Republics of the Russian Federation: Karachay-Cherkessia, Kabardino-Balkaria, and North Ossetia. In the Ossetian part of the Northern Caucasus the network of GPS survey-mode sites has been deployed as well. The GPS velocities confirm weak general compression of the Northern Caucasus with at the rate of about 1-2 mm/year. This horizontal motion at the boundary of the Northern Caucasus with respect to the Eurasian plate causes the higher seismic and tectonic activity of this transition zone. This result confirms that the source of deformation of the Northern Caucasus is the sub-meridional drift of the Arabian plate towards the adjacent boundary of the Eastern European part of the Eurasian lithospheric plate. The concept of such convergence implies that the Caucasian segment of the Alpine-Himalayan mobile belt is under compression, the layers of sedimentary and volcanic rocks are folded, the basement blocks are subject to shifts in various directions, and the upper crust layers are ruptured by reverse faults and thrusts. Weak deviation of observed velocities from the pattern corresponding to homogeneous compression can also be revealed, and numerical modeling of deformations of major regional tectonic structures, such as the Main Caucasus Ridge, can explain this. The deformation tensor deduced from the velocity field also exhibits the sub-meridional direction of the major compressional axes which coincides with the direction of

  20. Inflow direction of interstellar neutrals deduced from pickup ion measurements at 1 AU

    NASA Astrophysics Data System (ADS)

    Drews, Christian; Berger, Lars; Wimmer-Schweingruber, Robert F.; Bochsler, Peter; Galvin, Antoinette B.; Klecker, Berndt; Möbius, Eberhard

    2012-09-01

    Observations of interstellar pickup ions inside the heliosphere provide an indirect method to access information on the surrounding interstellar medium. The so-called pickup ion focusing cone and pickup ion crescent, which show an imprint of the related longitudinal distribution of interstellar neutrals in form of two overabundances on the down- and upwind side of the sun, are both believed to be aligned along the inflow vector of the interstellar medium. By finding their longitudinal positions, we can give an accurate value for the inflow direction λISM of interstellar matter. For that we performed an epoch analysis of interstellar pickup ions measured by the PLAsma and SupraThermal Ion Composition instrument (PLASTIC) on the Solar TErrestrial RElations Observatory mission (STEREO) and were able to reveal in situ the longitudinal distribution of interstellar He+, O+, and Ne+ pickup ions in the ecliptic plane at 1 AU. The previously accepted values for the inflow direction of interstellar matter in ecliptic longitude, as obtained with Ulysses/GAS (λ = 75.4° ± 0.5°), Prognoz 6 (λ = 74.5° ± 1°), and ACE/SWICS (λ = 74.43° ± 0.33°), are currently debated, especially in view of recent results from the Interstellar Boundary Explorer (IBEX) mission that show an inflow direction of interstellar neutral helium of λ = 79° + 3.0°(-3.5°). Four years of data collected with PLASTIC aboard STEREO A provided statistics sufficient not only to obtain values for the inflow direction of interstellar helium (λCone = 77.4° ± 1.9° and λCrescent = 80.4° ± 5.4°, deduced from an analysis of the He+ focusing cone and crescent, respectively) but also to derive values for the inflow direction of interstellar neon (λCone = 77.4° ± 5.0° and λCrescent = 79.7° ± 2.6°) and oxygen (λCrescent = 78.9° ± 3.1°). Although our values for He+, O+, and Ne+ are consistent with results from ACE, Ulysses, and Prognoz 6, considering the statistical and systematic

  1. The Stress Field of Eastern Africa Deduced From new Focal Mechanisms

    NASA Astrophysics Data System (ADS)

    Barth, A.; Wenzel, F.

    2006-12-01

    The East African Rift intersects the African continent from North to South for over 3000~km. Especially for regions neighbouring the rift only limited information on the stress regime is available. This is primarily due to a lack of earthquake source mechanism information, from which stress orientations can be deduced. Most of strong earthquakes occur within the rift zone, so that for these events focal mechanisms are calculated routinely by the Harvard CMT-group by moment tensor inversion using teleseismic data. However, apart from the rift earthquake magnitudes are often below their threshold of MW ~5.0 and thus CMT-solutions are hardly available. We developed a semi-automatic and frequency sensitive moment tensor inversion that allows us to determine source mechanisms of these light to moderate magnitude events. We present focal mechanism of 40 earthquakes with magnitudes ranging between 4.4~≤ MW ≤~5.4 taken from the years 1995-2002 that were not studied previously. We invert data from permanent recording seismometers with source-receiver distances up to 3000 km within variable frequency bands between 13 mHz and 29 mHz. For the formal stress inversion we use these new results, all 90 CMT-solutions available for Eastern Africa (1977-2005) and 17 focal mechanisms determined by moment tensor inversion from other authors. Finally, we divide Eastern Africa into 11 regions, binning the earthquake source mechanisms to perform the stress inversion. To analyse the dependence of the resulting stress tensors on the binning, we change regional partitioning systematically. We obtain stable stress tensors that show extensional regimes all over Eastern Africa with the maximum horizontal stress SH orientated in North-South direction. Beside this, we observe variations of SH in the vicinity of the Eastern rift branch (Kenya-Rift) towards Lake Victoria, where SH is rotated nearly perpendicular to the rift orientation. Moreover in the high plateau region West of Lake Malawi

  2. Inflow Direction of Interstellar Neutrals deduced from Pickup Ion Measurements at 1 AU

    NASA Astrophysics Data System (ADS)

    Drews, C.; Berger, L.; Wimmer-Schweingruber, R. F.

    2012-04-01

    The, so called, interstellar pickup ions are born from ionization of the interstellar neutral background gas by solar UV radiation or charge exchange with solar wind protons. The low speed of these interstellar particles in respect to the solar wind, forces them - after ionization - on circular orbits around the magnetic field, which is embedded into the solar wind. As a result, interstellar pickup ions show very characteristic velocity spectra with a sharp cut-off at 2·vSW, once they have been picked up by the solar wind. Furthermore, the influence by the Sun's gravitational force and UV radiation results in a very characteristic angular distribution in the eclitpic plane featuring two distinct structures, that are both believed to be aligned along the inflow direction of interstellar matter. Here we present recent observations of interstellar pickup ions with the Plasma and Suprathermal Ion Composition instrument (PLASTIC) mounted on the Solar TErrestrial RElations Observatory A (STEREO A). PLASTIC is a time-of-flight mass spectrometer, that determines the velocity, mass and charge of incoming ions by measuring their energy-per-charge, total energy and time-of-flight. STEREO PLASTIC's big geometric factor and the unusual prolonged solar minimum allows for the first time investigation of heavy pickup ions with unprecedented quality. Within the framework of our analysis we have performed a superposed epoch analysis of four consecutive STEREO A orbits that allowed us to reveal in-situ the angular distribution of He+ as well as heavy pickup ions (O+ and Ne+) at 1 AU. By analysing the interstellar features, namely the interstellar focusing cone and crescent, of the He+, O+ and Ne+ signature, we were able to estimate the inflow direction of interstellar helium as well as interstellar oxygen and neon. Our measurments revealed an inflow direction of λHe+ = 77.37°, λO+ = 78.42°, and λNe+ = 77.44°, which deviates from previously published results, deduced from the

  3. Incorporation of single dinitrophenyl-modified proteins in to the 30S subunit of Escherichia coli ribosomes by total reconstitution for localization by immune electron microscopy

    SciTech Connect

    Olah, T.V.

    1989-01-01

    The ribosome is a structurally defined organelle whose function is central to the existence of all organisms. It is the unique site of protein biosynthesis in all cells. A detailed understanding of ribosome structure is essential in understanding the process of translation. This thesis represents a new approach to the systematic localization of individual proteins contained in the small subunit of Escherichia coli ribosomes using immunoelectron microscopy. All 30S proteins were purified using high performance liquid chromatography (HPLC) and eight isolated proteins (S12,S21,S14,S19,S18,S17,S16 and S13) were derivatized with 2,4-(3,5-{sup 3}H)dinitrofluorobenzene (DNFB). The extent of modification of these proteins was estimated by both radioactivity and integrated peak areas, using dual wavelength monitoring at 214nm to detect protein and 360nm (to detect dinitrophenyl groups). Each dinitrophenylated protein was introduced in place of the corresponding unmodified protein into totally reconstituted 30S subunits. Antibodies raised against the DNP-hapten bound effectively to such reconstituted subunits and did not cause dissociation of the modified protein from the subunit. Electron microscopy of the immune complexes was used to localize the modified protein on the subunit surface. Incorporation of any of the DNP-modified proteins, with the exception of DNP-S18, does not interfere with the functionality of the ribosome as measure by the binding of Phe-tRNA{sup Phe} or the synthesis of poly(Phe) in a poly(U)-dependent manner. Results show that unmodified protein competes with DNP-protein and that DNP-protein can function, as its native counterpart, in stimulating uptake of specific proteins during reconstitution. This data provides evidence that each DNP-protein occupies the same position in 30S subunits as does the corresponding unmodified protein.

  4. DEDUCE Clinical Text: An Ontology-based Module to Support Self-Service Clinical Notes Exploration and Cohort Development.

    PubMed

    Roth, Christopher; Rusincovitch, Shelley A; Horvath, Monica M; Brinson, Stephanie; Evans, Steve; Shang, Howard C; Ferranti, Jeffrey M

    2013-01-01

    Large amounts of information, as well as opportunities for informing research, education, and operations, are contained within clinical text such as radiology reports and pathology reports. However, this content is less accessible and harder to leverage than structured, discrete data. We report on an extension to the Duke Enterprise Data Unified Content Explorer (DEDUCE), a self-service query tool developed to provide clinicians and researchers with access to data within the Duke Medicine Enterprise Data Warehouse (EDW). The DEDUCE Clinical Text module supports ontology-based text searching, enhanced filtering capabilities based on document attributes, and integration of clinical text with structured data and cohort development. The module is implemented with open-source tools extensible to other institutions, including a Java-based search engine (Apache Solr) with complementary full-text indexing library (Lucene) employed with a negation engine (NegEx) modified by clinical users to include to local domain-specific negation phrases. PMID:24303270

  5. Amino-terminal amino acid sequence of the major structural polypeptides of avian retroviruses: sequence homology between reticuloendotheliosis virus p30 and p30s of mammalian retroviruses.

    PubMed Central

    Hunter, E; Bhown, A S; Bennett, J C

    1978-01-01

    The major structural polypeptides, p30 of reticuloendotheliosis virus (REV) (strain T) and p27 of avian sarcoma virus B77, have been compared with regard to amino acid composition. NH2-terminal amino acid sequence, and immunological crossreactions. The amino acid composition of the two polypeptides is distinct, and a comparison of the first 30 NH2-terminal amino acids of REV p30 with that for the first 25 of B77 p27 yields only three homologous residues. In competition radioimmunoassays the polypeptides show no crossreactivity. A comparison of the amino acid composition and NH2-terminal amino acid sequence of REV p30 with those reported for several mammalian retrovirus p30s shows remarkable similarities. Both REV and mammalian p30s contain a large number of polar residues in their amino acid composition and show approximately 40% homology in the first 30 NH2-terminal amino acids. No crossreactivity could be observed, however, in competition radioimmunoassays between Rauscher murine leukemia virus p30 and that of REV. The observations reported here suggest a close evolutionary relationship between REV and the mammalian retroviruses. Images PMID:208072

  6. The antibiotic Furvina® targets the P-site of 30S ribosomal subunits and inhibits translation initiation displaying start codon bias

    PubMed Central

    Fabbretti, Attilio; Brandi, Letizia; Petrelli, Dezemona; Pon, Cynthia L.; Castañedo, Nilo R.; Medina, Ricardo; Gualerzi, Claudio O.

    2012-01-01

    Furvina®, also denominated G1 (MW 297), is a synthetic nitrovinylfuran [2-bromo-5-(2-bromo-2-nitrovinyl)-furan] antibiotic with a broad antimicrobial spectrum. An ointment (Dermofural®) containing G1 as the only active principle is currently marketed in Cuba and successfully used to treat dermatological infections. Here we describe the molecular target and mechanism of action of G1 in bacteria and demonstrate that in vivo G1 preferentially inhibits protein synthesis over RNA, DNA and cell wall synthesis. Furthermore, we demonstrate that G1 targets the small ribosomal subunit, binds at or near the P-decoding site and inhibits its function interfering with the ribosomal binding of fMet-tRNA during 30S initiation complex (IC) formation ultimately inhibiting translation. Notably, this G1 inhibition displays a bias for the nature (purine vs. pyrimidine) of the 3′-base of the codon, occurring efficiently only when the mRNA directing 30S IC formation and translation contains the canonical AUG initiation triplet or the rarely found AUA triplet, but hardly occurs when the mRNA start codon is either one of the non-canonical triplets AUU or AUC. This codon discrimination by G1 is reminiscent, though of opposite type of that displayed by IF3 in its fidelity function, and remarkably does not occur in the absence of this factor. PMID:22941660

  7. The antibiotic Furvina® targets the P-site of 30S ribosomal subunits and inhibits translation initiation displaying start codon bias.

    PubMed

    Fabbretti, Attilio; Brandi, Letizia; Petrelli, Dezemona; Pon, Cynthia L; Castañedo, Nilo R; Medina, Ricardo; Gualerzi, Claudio O

    2012-11-01

    Furvina®, also denominated G1 (MW 297), is a synthetic nitrovinylfuran [2-bromo-5-(2-bromo-2-nitrovinyl)-furan] antibiotic with a broad antimicrobial spectrum. An ointment (Dermofural®) containing G1 as the only active principle is currently marketed in Cuba and successfully used to treat dermatological infections. Here we describe the molecular target and mechanism of action of G1 in bacteria and demonstrate that in vivo G1 preferentially inhibits protein synthesis over RNA, DNA and cell wall synthesis. Furthermore, we demonstrate that G1 targets the small ribosomal subunit, binds at or near the P-decoding site and inhibits its function interfering with the ribosomal binding of fMet-tRNA during 30S initiation complex (IC) formation ultimately inhibiting translation. Notably, this G1 inhibition displays a bias for the nature (purine vs. pyrimidine) of the 3'-base of the codon, occurring efficiently only when the mRNA directing 30S IC formation and translation contains the canonical AUG initiation triplet or the rarely found AUA triplet, but hardly occurs when the mRNA start codon is either one of the non-canonical triplets AUU or AUC. This codon discrimination by G1 is reminiscent, though of opposite type of that displayed by IF3 in its fidelity function, and remarkably does not occur in the absence of this factor. PMID:22941660

  8. Structural change of E. coli separated and complexed 30S and 50S ribosomal subunits due to Mg 2+ ions: SANS experiments

    NASA Astrophysics Data System (ADS)

    Briganti, G.; Pedone, F.; Giansanti, A.; Giordano, R.

    1995-02-01

    Small-angle neutron-scattering experiments have been performed on E. Coli 70S ribosomes and on 50S and 30S separated subunits in the presence and absence of magnesium ions. In the 70S complex in presence of magnesium, the scattering intensity at Q = 0 ( I(0)) is roughly two times higher than without magnesium, in apparent agreement with the general view of an association-dissociation of the subunits induced by magnesium. But a similar increment is observed in both separated subunits too. The probability distribution functions of the intra-particle distance p( r), obtained by Fourier transforming, the experimental data, indicate that, even at low temperature (5°C) and concentration (0.1 wt%), the 70S and the separated subunits form aggregates. In all samples, the absence of Mg 2+ ions shifts and shrinks p( r) in the single-particle region, below 200 Å, and affects the shape of the curve in the aggregate region. Our results suggest that the presence of Mg 2+ ions does not strongly affect the degree of complexation of the subunits: the 70S complex retains its individuality even in the absence of magnesium, but undergoes structural rearrangements similar to those in 30S and 50S.

  9. Lu Hf and Ar Ar chronometry supports extreme rate of subduction zone metamorphism deduced from geospeedometry

    NASA Astrophysics Data System (ADS)

    Philippot, Pascal; Blichert-Toft, Janne; Perchuk, Alexei; Costa, Sylvie; Gerasimov, Vladimir

    2001-12-01

    temperatures are equivalent to or in the upper range of peak metamorphic temperatures. With respect to Ar, calculated closure temperatures of 570 °C for the Yukon eclogites and 560-600 °C for the Great Caucasus eclogites are within error of the temperatures of the early stage of cooling and/or exhumation. These results indicate that the eclogitic rocks experienced a minimum cooling and exhumation of about 150 °C and 25 km in a time interval smaller than the errors on the ages. The fact that garnet and phengite yield indistinguishable Lu-Hf and Ar-Ar ages is in good agreement with the observation deduced from geospeedometry that the time elapsed at eclogitic conditions should be extremely short (of the order of 1 Ma). Considering the exceptional precision of the age information obtained on eclogitic garnet using the Lu-Hf technique and that Lu-Hf, Ar-Ar and geospeedometry approaches were carried out the same samples, these results suggest that the time-scale resolution required for unraveling rates of high-pressure metamorphism remains out of reach of current thermochronological methods.

  10. CMB and the elementary particles structure deduced from QFT of non-dot model

    NASA Astrophysics Data System (ADS)

    Chen, Shao-Guang

    In my paper ‘Planck Constant Deduced from Metrical Results of Doppler Effect of Moving Particle —Uncertainty Principle Caused by Collision of a Particle with CMB Photons and Virtual Photons (H05-0036-10)’ the absolute velocity is decided by CMB which as a mark of the vacuum. CMB come from the thermal radiation of stars via gravitational redshift about 10 (13) year (E14- 0032-08). In my paper ‘Quanta turn-advance ism, China Science && Technology Overview 131 192-210 (2011)’, QFT four-dimensional uncertainty principle and momentum-energy conservation law had been generalized as a five-dimensional equations: de Broglie wavelength as a position vector \\underline{q}= (i c t, r, s), momentum \\underline{P} = (i E / c, P, U c), \\underline{q} = i h / \\underline{P}, \\underline{q} \\underline{q} = 0, \\underline{P} \\underline{P} = 0, Sigma∑ \\underline{P} = \\underline{P} (0) . The five-dimensional time-space-spin had been quantized as a non-dot model basic cell, the lowest energy state vertical polarized left spin 1/2 neutrino and right spin 1/2 antineutrino are just the left, right advance unit quanta _{0}nuυ, nuυ _{0} and left, right back unit quanta (0) nuυ, nuυ (0) , it again compose into spin 1 unit advance photons _{0}nuυnuυ _{0} and back (0) nuυnuυ (0) , spin 0 unit rest mass nuυ _{0}nuυ (0) and anti-mass _{0}nuυ (0) nuυ, spin 0 unit positive charge _{0}nuυnuυ (0) and negative charge nuυ _{0} (0) nuυ. It accord to the high energy physics experimental results of the transformation among the photons, masses quanta and charges quanta. The physical vacuum is the even collocation of non-combinational nuυ _{0} or _{0}nuυ. QFT is no longer with divergence difficulty by the non-dot model. It is mathematically easy that from five-dimensional equations deduce out the Dirac, Klein-Gordan, Maxwell equations and Lorentz force formula, but appear some new results. The interactions between _{0}nuυ, nuυ _{0}, (0) nuυ, nuυ (0) , i.e., force f

  11. Serial femtosecond X-ray diffraction of 30S ribosomal subunit microcrystals in liquid suspension at ambient temperature using an X-ray free-electron laser

    PubMed Central

    Demirci, Hasan; Sierra, Raymond G.; Laksmono, Hartawan; Shoeman, Robert L.; Botha, Sabine; Barends, Thomas R. M.; Nass, Karol; Schlichting, Ilme; Doak, R. Bruce; Gati, Cornelius; Williams, Garth J.; Boutet, Sébastien; Messerschmidt, Marc; Jogl, Gerwald; Dahlberg, Albert E.; Gregory, Steven T.; Bogan, Michael J.

    2013-01-01

    High-resolution ribosome structures determined by X-ray crystallography have provided important insights into the mechanism of translation. Such studies have thus far relied on large ribosome crystals kept at cryogenic temperatures to reduce radiation damage. Here, the application of serial femtosecond X-ray crystallography (SFX) using an X-ray free-electron laser (XFEL) to obtain diffraction data from ribosome microcrystals in liquid suspension at ambient temperature is described. 30S ribosomal subunit microcrystals diffracted to beyond 6 Å resolution, demonstrating the feasibility of using SFX for ribosome structural studies. The ability to collect diffraction data at near-physiological temperatures promises to provide fundamental insights into the structural dynamics of the ribosome and its functional complexes. PMID:23989164

  12. Structural change induced by removal of magnesium ions on E. coli 70S ribosomes and 30S and 50S separated subunits

    NASA Astrophysics Data System (ADS)

    Briganti, G.; Giansanti, A.; Bonincontro, A.; Mengoni, M.; Giordano, R.

    1996-09-01

    To clarify the intra- and inter-particle effects of magnesium ions on E. coli ribosomes we have performed measurements of light scattering intensity, index of refraction and small-angle neutron scattering on the 70S complex and 30S and 50S subunits with and without magnesium. The results indicate that magnesium has a specific intra-particle effect on the subunits as well as on the 70S complex. Besides, the distance distribution function shows that magnesium has an effect on the supra-ribosomal aggregation. The combination of these intra- and inter-particle effects completely hides, in the scattering experiments, any effect of magnesium on the degree of association of the two subunits into the 70S complex.

  13. Physical and biochemical nature of the bacterial cytoplasm: movement and localization of mRNA and the 30S subunits of ribosomes.

    PubMed

    Trevors, J T

    2012-05-01

    There is a paucity of knowledge on how mRNA transcripts in the spatially crowded, but molecularly organized bacterial cytoplasm contact the 30S ribosomal subunits. Does simple diffusion in the cytoplasm account for transcript-ribosome interactions given that a large number of ribosomes (e.g., about 72,000 in Escherichia coli during exponential growth) can be present in the cytoplasm? Or are undiscovered mechanisms present where specific transcripts are directed to specific ribosomes at specific cytoplasmic locations, while others are mobilized in a random manner? Moreover, is it possible that cytoplasmic mobilization occurs in bacteria, driven possibly by thermal infrared (IR) radiation and the generation of exclusion zone (EZ) water? These aspects will be discussed in this article and hypotheses presented. PMID:22710107

  14. A Woman in Her 30s With a Past History of HIV Disease Presented With Recurrent Fever, Night Sweats, and Small Bilateral Pulmonary Nodules.

    PubMed

    Hashmi, Hafiz Rizwan Talib; Niazi, Masooma; Adrish, Muhammad

    2016-06-01

    A woman in her 30s presented with recurrent low-grade fever and cough (onset, 1 week). She reported occasional night sweats and weight loss of approximately 20 pounds over the past 4 months. She denied nausea, vomiting, diarrhea, or any urinary complaints. Her past medical history was significant for chronic hepatitis C and HIV infection, the latter diagnosed in 2001. She was noncompliant with highly active antiretroviral therapy for more than 4 years and had pneumocystis pneumonia 2 years prior to this presentation. She had a 10-pack per year smoking history and reported active use of cocaine and heroin. The patient denied any occupational exposures. PMID:27287594

  15. Deducing the electron-beam diameter in a laser-plasma accelerator using x-ray betatron radiation.

    PubMed

    Schnell, Michael; Sävert, Alexander; Landgraf, Björn; Reuter, Maria; Nicolai, Maria; Jäckel, Oliver; Peth, Christian; Thiele, Tobias; Jansen, Oliver; Pukhov, Alexander; Willi, Oswald; Kaluza, Malte C; Spielmann, Christian

    2012-02-17

    We investigate the properties of a laser-plasma electron accelerator as a bright source of keV x-ray radiation. During the interaction, the electrons undergo betatron oscillations and from the carefully measured x-ray spectrum the oscillation amplitude of the electrons can be deduced which decreases with increasing electron energies. From the oscillation amplitude and the independently measured x-ray source size of (1.8±0.3) μm we are able to estimate the electron bunch diameter to be (1.6±0.3) μm. PMID:22401215

  16. Protein-RNA crosslinking in Escherichia coli 30S ribosomal subunits. Identification of a 16S rRNA fragment crosslinked to protein S12 by the use of the chemical crosslinking reagent 1-ethyl-3-dimethyl-aminopropylcarbodiimide.

    PubMed Central

    Chiaruttini, C; Expert-Bezançon, A; Hayes, D; Ehresmann, B

    1982-01-01

    1-ethyl-3-dimethyl aminopropylcarbodiimide (EDC) was used to cross-link 30S ribosomal proteins to 16S rRNA within the E. coli 3OS ribosomal subunit. Covalently linked complexes containing 30S proteins and 16S rRNA, isolated by sedimentation of dissociated crosslinked 30S subunits through SDS containing sucrose gradients, were digested with RNase T1, and the resulting oligonucleotide-protein complexes were fractionated on SDS containing polyacrylamide gels. Eluted complexes containing 30S proteins S9 and S12 linked to oligonucleotides were obtained in pure form. Oligonucleotide 5'terminal labelling was successful in the case of S12 containing but not of the S9 containing complex and led to identification of the S12 bound oligonucleotide as CAACUCG which is located at positions 1316-1322 in the 16S rRNA sequence. Protein S12 is crosslinked to the terminal G of this heptanucleotide. Images PMID:6760129

  17. Interconversion of active and inactive 30 S ribosomal subunits is accompanied by a conformational change in the decoding region of 16 S rRNA.

    PubMed

    Moazed, D; Van Stolk, B J; Douthwaite, S; Noller, H F

    1986-10-01

    Zamir, Elson and their co-workers have shown that 30 S ribosomal subunits are reversibly inactivated by depletion of monovalent or divalent cations. We have re-investigated the conformation of 16 S rRNA in the active and inactive forms of the 30 S subunit, using a strategy that is designed to eliminate reversible ion-dependent conformational effects that are unrelated to the heat-dependent Zamir-Elson transition. A combination of structure-specific chemical probes enables us to monitor the accessibility of pyrimidines at N-3 and purines at N-1 and N-7. Chemically modified bases are identified by end-labeling followed by analine-induced strand scission (in some cases preceded by hybrid selection), or by primer extension using synthetic DNA oligomers. These studies show the following: The transition from the active to the inactive state cannot be described as a simple loosening or unfolding of native structure, such as that which is observed under conditions of more severe ion depletion. Instead, it has the appearance of a reciprocal interconversion between two differently structured states; some bases become more reactive toward the probes, whilst others become less reactive as a result of inactivation. Changes in reactivity are almost exclusively confined to the "decoding site" centered at positions 1400 and 1500, but significant differences are also detected at U723 and G791 in the central domain. This may reflect possible structural and functional interactions between the central and 3' regions of 16 S rRNA. The inactive form also shows significantly decreased reactivity at positions 1533 to 1538 (the Shine-Dalgarno region), in agreement with earlier findings. The principal changes in reactivity involve the universally conserved nucleotides G926, C1395, A1398 and G1401. The three purines show reciprocal behavior at their N-1 versus N-7 positions. G926 loses its reactivity at N-1, but becomes highly reactive at N-7 as a result of the transition of the inactive

  18. Mutations in the leader region of ribosomal RNA operons cause structurally defective 30 S ribosomes as revealed by in vivo structural probing.

    PubMed

    Balzer, M; Wagner, R

    1998-02-27

    The biogenesis of functional ribosomes is regulated in a very complex manner, involving different proteins and RNA molecules. RNAs are not only essential components of both ribosomal subunits but also transiently interacting factors during particle formation. In eukaryotes snoRNAs act as molecular chaperones to assist maturation, modification and assembly. In a very similar way highly conserved leader sequences of bacterial rRNA operons are involved in the correct formation of 30 S ribosomal subunits. Certain mutations in the rRNA leader region cause severe growth defects due to malfunction of ribosomes which are assembled from such transcription units. To understand how the leader sequences act to facilitate the formation of the correct 30 S subunits we performed in vivo chemical probing to assess structural differences between ribosomes assembled either from rRNA transcribed from wild-type operons or from operons which contain mutations in the rRNA leader region. Cells transformed with plasmids containing the respective rRNA operons were reacted with dimethylsulphate (DMS). Ribosomes were isolated by sucrose gradient centrifugation and modified nucleotides within the 16 S rRNA were identified by primer extension reaction. Structural differences between ribosomes from wild-type and mutant rRNA operons occur in several clusters within the 16 S rRNA secondary structure. The most prominent differences are located in the central domain including the universally conserved pseudoknot structure which connects the 5', the central and the 3' domain of 16 S rRNA. Two other clusters with structural differences fall in the 5' domain where the leader had been shown to interact with mature 16 S rRNA and within the ribosomal protein S4 binding site. The other differences in structure are located in sites which are also known as sites for the action of several antibiotics. The data explain the functional defects of ribosomes from rRNA operons with leader mutations and help to

  19. 30S Subunit-Dependent Activation of the Sorangium cellulosum So ce56 Aminoglycoside Resistance-Conferring 16S rRNA Methyltransferase Kmr

    PubMed Central

    Savic, Miloje; Sunita, S.; Zelinskaya, Natalia; Desai, Pooja M.; Macmaster, Rachel; Vinal, Kellie

    2015-01-01

    Methylation of bacterial 16S rRNA within the ribosomal decoding center confers exceptionally high resistance to aminoglycoside antibiotics. This resistance mechanism is exploited by aminoglycoside producers for self-protection while functionally equivalent methyltransferases have been acquired by human and animal pathogenic bacteria. Here, we report structural and functional analyses of the Sorangium cellulosum So ce56 aminoglycoside resistance-conferring methyltransferase Kmr. Our results demonstrate that Kmr is a 16S rRNA methyltransferase acting at residue A1408 to confer a canonical aminoglycoside resistance spectrum in Escherichia coli. Kmr possesses a class I methyltransferase core fold but with dramatic differences in the regions which augment this structure to confer substrate specificity in functionally related enzymes. Most strikingly, the region linking core β-strands 6 and 7, which forms part of the S-adenosyl-l-methionine (SAM) binding pocket and contributes to base flipping by the m1A1408 methyltransferase NpmA, is disordered in Kmr, correlating with an exceptionally weak affinity for SAM. Kmr is unexpectedly insensitive to substitutions of residues critical for activity of other 16S rRNA (A1408) methyltransferases and also to the effects of by-product inhibition by S-adenosylhomocysteine (SAH). Collectively, our results indicate that adoption of a catalytically competent Kmr conformation and binding of the obligatory cosubstrate SAM must be induced by interaction with the 30S subunit substrate. PMID:25733511

  20. Lithium- and boron-bearing brines in the Central Andes: exploring hydrofacies on the eastern Puna plateau between 23° and 23°30'S

    NASA Astrophysics Data System (ADS)

    Steinmetz, R. L. López

    2016-04-01

    Internally drained basins of the Andean Plateau are lithium- and boron-bearing systems. The exploration of ionic facies and parental links in a playa lake located in the eastern Puna (23°-23°30'S) was assessed by hydrochemical determinations of residual brines, feed waters and solutions from weathered rocks. Residual brines have been characterized by the Cl- (SO4 =)/Na+ (K+) ratio. Residual brines from the playa lake contain up to 450 mg/l of boron and up to 125 mg/l of lithium, and the Las Burras River supplies the most concentrated boron (20 mg/l) and lithium (3.75 mg/l) inflows of the basin. The hydro-geochemical assessment allowed for the identification of three simultaneous sources of boron: (1) inflow originating from granitic areas of the Aguilar and Tusaquillas ranges; (2) weathering of the Ordovician basement; and (3) boron-rich water from the Las Burras River. Most of the lithium input of the basin is likely generated by present geothermal sources rather than by weathering and leaching of ignimbrites and plutonic rocks. However, XRD analyses of playa lake sediments revealed the presence of lithian micas of clastic origin, including taeniolite and eucriptite. This study is the first to document these rare Li-micas from the Puna basin. Thus, both residual brines and lithian micas contribute to the total Li content in the studied hydrologic system.

  1. Fracture-mechanics data deduced from thermal-shock and related experiments with LWR pressure-vessel material

    SciTech Connect

    Cheverton, R.D.; Canonico, D.A.; Iskander, S.K.; Bolt, S.E.; Holz, P.P.; Nanstad, R.K.; Stelzman, W.J.

    1982-01-01

    Pressurized water reactors (PWRs) are susceptible to certain types of hypothetical accidents that can subject the reactor pressure vessel to severe thermal shock, that is, a rapid cooling of the inner surface of the vessel wall. The thermal-shock loading, coupled with the radiation-induced reduction in the material fracture toughness, introduces the possibility of propagation of preexistent flaws and what at one time were regarded as somewhat unique fracture-oriented conditions. Several postulated reactor accidents have been analyzed to discover flaw behavior trends; seven intermediate-scale thermal-shock experiments with steel cylinders have been conducted; and corresponding materials characterization studies have been performed. Flaw behavior trends and related fracture-mechanics data deduced from these studies are discussed.

  2. Structural and functional characterization of hBD-1(Ser35), a peptide deduced from a DEFB1 polymorphism.

    PubMed

    Circo, Raffaella; Skerlavaj, Barbara; Gennaro, Renato; Amoroso, Antonio; Zanetti, Margherita

    2002-04-26

    beta-Defensins are mammalian antimicrobial peptides that share a unique disulfide-bonding motif of six conserved cysteines. An intragenic polymorphism of the DEFB1 gene that changes a highly conserved Cys to Ser in the peptide coding region has recently been described. The deduced peptide cannot form three disulfide bonds, as one of the cysteines is unpaired. We have determined the cysteine connectivities of a corresponding synthetic hBD-1(Ser35) peptide, investigated the structure by circular dichroism spectroscopy, and assayed the in vitro antimicrobial activity. Despite a different arrangement of the disulfides, hBD-1(Ser35) proved as active as hBD-1 against the microorganisms tested. This activity likely depends on the ability of hBD-1(Ser35) to adopt an amphipathic conformation in hydrophobic environment, similar to the wild type peptide, as suggested by CD spectroscopy. PMID:12054642

  3. Measurements of the magnetic field orientation in the Jovian ionosphere deduced from Pioneer 10 and 11 scintillation observations

    NASA Technical Reports Server (NTRS)

    Woo, R.; Yang, F.-C.

    1978-01-01

    In this paper the S band scintillations observed during the Pioneer 10 and 11 occultation measurements of Jupiter are analyzed. It is found that while the electron density irregularities are isotropic in the collision-dominated lower ionosphere, they are anisotropic in the upper ionosphere because of alignment along the magnetic field. By using Rytov's approximation the frequency spectrum of the log-amplitude scintillations is derived for a wave propagating in an anisotropic turbulent medium. It is shown that the spectrum depends to a large extent on the direction of anisotropy and is therefore useful for measuring the orientation of the magnetic field in regions that have not yet been probed by direct measurements. This new technique is applied to the Pioneer 10 and 11 observations, and is used to deduce the first measurements of magnetic field orientation in the ionosphere of Jupiter.

  4. Parametric model of the Mueller matrix of a Spectralon white reflectance standard deduced by polar decomposition techniques.

    PubMed

    Kildemo, Morten; Maria, Jérôme; Ellingsen, Pål G; Aas, Lars M S

    2013-07-29

    Decomposition methods have been applied to in-plane Mueller matrix ellipsometric scattering data of the Spectralon reflectance standard. Data were measured at the wavelengths 532 nm and 1500 nm, using an achromatic optimal Mueller matrix scatterometer applying a photomultiplier tube and a high gain InGaAs detector for the two wavelengths. A parametric model with physical significance was deduced through analysis of the product decomposed matrices. It is found that when the data are analyzed as a function of the scattering angle, similar to particle scattering, the matrix elements are largely independent of incidence angle. To the first order, we propose that a Guassian lineshape is appropriate to describe the polarization index, while the decomposed diagonal elements of the retardance matrix have a form resembling Rayleigh single scattering. New models are proposed for the off diagonal elements of the measured Mueller matrix. PMID:23938723

  5. Estimate of carbonyl sulfide (OCS) volcanic source strength deduced from OCS/CO2 ratios in volcanic gases

    NASA Astrophysics Data System (ADS)

    Belviso, S.; Nguyen, B. C.; Allard, P.

    1986-02-01

    Measurements of the concentration ratio of OCS and CO2 were made in fumaroles of several volcanoes in Italy and Nicaragua. The values obtained, together with previous published data, demonstrate that the OCS/CO2 ratio is positively correlated with the emission temperature of the gases. It ranges from 10 to the -7.1 power to 10 to the -2.7 power at the Vulcano (90 C) and Erta'Ale (1130/C) volcanoes, respectively. The global OCS volcanic source strength, deduced from SO2 emission rates, CO2/SO2 and OCS/CO2 ratios in volcanic gases, is estimated to be in the range 6-90 x 10 to the 9th g OCS per year.

  6. The interstellar redding law in the ultraviolet deduced from filter photometry obtained by the OAO-2 satellite

    NASA Technical Reports Server (NTRS)

    Laget, M.

    1972-01-01

    Filter photometry has been obtained of 16 BO stars at ten effective wavelengths in the range 4250-1430 A. The wavelength dependence of the interstellar reddening law, deduced from a least squares fit of the observed values to the reddening line at each band, is found in satisfactory agreement with that derived by Bless and Savage (1972). Toward the shorter wavelengths the increase of the computed probable error of the slope of the mean reddening line suggests that large fluctuations in the law may occur from star to star. Similar computations, separating main-sequence stars and supergiants, indicate that the large fluctuations of the law appear to be well related to the luminosity of the stars; the supergiants show systematically less extinction, this deficiency becoming large toward the far UV. The small number in the sample however, does not allow a general conclusion to be drawn.

  7. Phenotypic Switching in Candida glabrata Accompanied by Changes in Expression of Genes with Deduced Functions in Copper Detoxification and Stress

    PubMed Central

    Srikantha, Thyagarajan; Zhao, Rui; Daniels, Karla; Radke, Josh; Soll, David R.

    2005-01-01

    Most strains of Candida glabrata switch spontaneously between a number of phenotypes distinguishable by graded brown coloration on agar containing 1 mM CuSO4, a phenomenon referred to as “core switching.” C. glabrata also switches spontaneously and reversibly from core phenotypes to an irregular wrinkle (IWr) phenotype, a phenomenon referred to as “irregular wrinkle switching.” To identify genes differentially expressed in the core phenotypes white (Wh) and dark brown (DB), a cDNA subtraction strategy was employed. Twenty-three genes were identified as up-regulated in DB, four in Wh, and six in IWr. Up-regulation was verified in two unrelated strains, one a and one α strain. The functions of these genes were deduced from the functions of their Saccharomyces cerevisiae orthologs. The majority of genes up-regulated in DB (78%) played deduced roles in copper assimilation, sulfur assimilation, and stress responses. These genes were differentially up-regulated in DB even though the conditions of growth for Wh and DB, including CuSO4 concentration, were identical. Hence, the regulation of these genes, normally regulated by environmental cues, has been usurped by switching, presumably as an adaptation to the challenging host environment. These results are consistent with the suggestion that switching provides colonizing populations with a minority of cells expressing a phenotype that allows them to enrich in response to an environmental challenge, a form of rapid adaptation. However, DB is the most commonly expressed phenotype at sites of host colonization, in the apparent absence of elevated copper levels. Hence, up-regulation of these genes by switching suggests that in some cases they may play roles in colonization and virulence not immediately obvious from the roles played by their orthologs in S. cerevisiae. PMID:16087748

  8. The NMR solution structure of the 30S ribosomal protein S27e encoded in gene RS27_ARCFU of Archaeoglobus fulgidis reveals a novel protein fold

    PubMed Central

    Herve du Penhoat, Catherine; Atreya, Hanudatta S.; Shen, Yang; Liu, Gaohua; Acton, Thomas B.; Xiao, Rong; Li, Zhaohui; Murray, Diana; Montelione, Gaetano T.; Szyperski, Thomas

    2004-01-01

    The Archaeoglobus fulgidis gene RS27_ARCFU encodes the 30S ribosomal protein S27e. Here, we present the high-quality NMR solution structure of this archaeal protein, which comprises a C4 zinc finger motif of the CX2CX14-16CX2C class. S27e was selected as a target of the Northeast Structural Genomics Consortium (target ID: GR2), and its three-dimensional structure is the first representative of a family of more than 116 homologous proteins occurring in eukaryotic and archaeal cells. As a salient feature of its molecular architecture, S27e exhibits a β-sandwich consisting of two three-stranded sheets with topology B(↓), A(↑), F(↓), and C(↑), D(↓), E(↑). Due to the uniqueness of the arrangement of the strands, the resulting fold was found to be novel. Residues that are highly conserved among the S27 proteins allowed identification of a structural motif of putative functional importance; a conserved hydrophobic patch may well play a pivotal role for functioning of S27 proteins, be it in archaeal or eukaryotic cells. The structure of human S27, which possesses a 26-residue amino-terminal extension when compared with the archaeal S27e, was modeled on the basis of two structural templates, S27e for the carboxy-terminal core and the amino-terminal segment of the archaeal ribosomal protein L37Ae for the extension. Remarkably, the electrostatic surface properties of archaeal and human proteins are predicted to be entirely different, pointing at either functional variations among archaeal and eukaryotic S27 proteins, or, assuming that the function remained invariant, to a concerted evolutionary change of the surface potential of proteins interacting with S27. PMID:15096641

  9. Geometrical analysis of the structure in the western flank of the Chilean Andes at 34°15'S-34°30'S

    NASA Astrophysics Data System (ADS)

    Jara, P. P.; Charrier, R.; Arriagada, C.; Farias, M.

    2007-12-01

    We present a structural analysis of strongly deformed Cenozoic volcanic rocks of the western Principal Cordillera between 34°15'S and 34°30'S. Deformation has been related to the inversion of the Abanico Basin occurred between 22 and 16 Ma. The structural array is characterized by a syncline with a very steep western limb and a rather flat slightly folded axial zone. On both sides of this structure, layers dip in directions opposite to the syncline flanks, suggesting disruption of anticlines by faulting. The reconstructed geometry performed on 6 cross- sections indicates that: 1. Deformation occurred by "fault-propagation folding" with considerable fault displacement, and 2. The anticlines were transported by the faults cutting their crests along the axial plane, similar to the anticlinal breakthrough deformation modes. Based on this mechanism and the relations between the axial and cut off angles, we developed a kinematic model using geometric methods and the Trishear program. Results suggests that folding was controlled by two E-vergent faults (western, WF, and eastern, EF). The most important (WF) would have a cutoff angle 40°-60°, which is compatible with inverted normal faults. Indeed, the regional nature of shortening in this region has been interpreted as the result of basin inversion. The EF has a cutoff angle of about 20 degrees, which is compatible with a neoformed thrust and allowing its interpretation as a short cut. These structures have accommodated ca. 30% (2 to 3 km) of shortening in this region. Although our proposition at depth for the main fault geometry is based on the surface analysis, it is quite consistent with the structural array interpreted by seismicity and MT images. Moreover, this structure seems to be the upward prolongation of a W-dipping ramp structure, connecting the subduction zone with the tectonic front of the mountain belt, in a zone where the ramp flattens and forms a detachment at 15-20 km depth beneath the western edge of

  10. New prospects for deducing the evolutionary history of metabolic pathways in prokaryotes: Aromatic biosynthesis as a case-in-point

    NASA Astrophysics Data System (ADS)

    Ahmad, Suhail; Jensen, Roy A.

    1988-03-01

    Metabolic pathways of prokaryotes are more biochemically diverse than is generally recognized. Distinctive biochemical features are shared by phylogenetic clusters. The hierarchical levels of characterstate clustering depends upon evolutionary events which fortuitously became fixed in the genome of a common ancestor. Prokaryotes can now be ordered on a phylogenetic tree. This allows the evolutionary steps that underlie the construction and regulation of appropriately complex biochemical pathways to be traced in an evolutionary progression of prokaryote types that house these pathways. Essentially the approach is to deduce ancestral character states at ever deeper phylogenetic levels, utilizing logical principles of maximum parsimony. The current perspective on the evolution of the biochemical pathway for biosynthesis of aromatic amino acids is developed as a case-in-point model for analyses that should be feasible with many major metabolic systems. Phenylalanine biosynthesis probably arose prior to the addition of branches leading to tyrosine and tryptophan. An evolutionary scenario is developed that begins with non-enzymatic reactions which may have operated in primitive systems, followed by the evolution of an enzymatic system that pre-dated the divergence of major lineages of modern eubacteria (Gram-positive bacteria, Gram-negative purple bacteria, and cyanobacteria).

  11. Evolutionary relationships of a plant-pathogenic mycoplasmalike organism and Acholeplasma laidlawii deduced from two ribosomal protein gene sequences.

    PubMed Central

    Lim, P O; Sears, B B

    1992-01-01

    The families within the class Mollicutes are distinguished by their morphologies, nutritional requirements, and abilities to metabolize certain compounds. Biosystematic classification of the plant-pathogenic mycoplasmalike organisms (MLOs) has been difficult because these organisms have not been cultured in vitro, and hence their nutritional requirements have not been determined nor have physiological characterizations been possible. To investigate the evolutionary relationship of the MLOs to other members of the class Mollicutes, a segment of a ribosomal protein operon was cloned and sequenced from an aster yellows-type MLO which is pathogenic for members of the genus Oenothera and from Acholeplasma laidlawii. The deduced amino acid sequence data from the rpl22 and rps3 genes indicate that the MLOs are more closely related to A. laidlawii than to animal mycoplasmas, confirming previous results from 16S rRNA sequence comparisons. This conclusion is also supported by the finding that the UGA codon is not read as a tryptophan codon in the MLO and A. laidlawii, in contrast to its usage in Mycoplasma capricolum. PMID:1556079

  12. Deducing receptor signaling parameters from in vivo analysis: LuxN/AI-1 quorum sensing in Vibrio harveyi

    PubMed Central

    Swem, Lee R.; Swem, Danielle L.; Wingreen, Ned S.; Bassler, Bonnie L.

    2008-01-01

    Summary Quorum sensing, a process of bacterial cell-cell communication, relies on production, detection, and response to autoinducer signaling molecules. Here we focus on LuxN, a nine transmembrane domain protein from Vibrio harveyi, and the founding example of membrane-bound receptors for acyl-homoserine lactone (AHL) autoinducers. Previously, nothing was known about signal recognition by membrane-bound AHL receptors. We used mutagenesis and suppressor analyses to identify the AHL-binding domain of LuxN, and discovered LuxN mutants that confer decreased and increased AHL sensitivity. Our analysis of dose-response curves of multiple LuxN mutants pins these inverse phenotypes on quantifiable opposing shifts in the free-energy bias of LuxN for its kinase and phosphatase states. To extract signaling parameters, we exploited a strong LuxN antagonist, one of fifteen small-molecule antagonists we identified. We find that quorum-sensing-mediated communication can be manipulated positively and negatively to control bacterial behavior, and that signaling parameters can be deduced from in vivo data. PMID:18692469

  13. Coseismic Slip Distribution of the 2011 off the Pacific Coast of Tohoku Earthquake Deduced from Land and Seafloor Geodesy

    NASA Astrophysics Data System (ADS)

    Iinuma, T.; Kido, M.; Osada, Y.; Inazu, D.; Ohzono, M.; Tsushima, H.; Hino, R.; Ohta, Y.; Suzuki, S.; Fujimoto, H.; Miura, S.; Shinohara, M.

    2011-12-01

    The 2011 off the Pacific coast of Tohoku Earthquake (M9.0) occurred on 11 March 2011 off the Pacific coast of Tohoku district, northeastern Japan, where the Pacific plate is subducting beneath the overriding continental plate. A number of models of the coseismic slip distribution of this earthquake have been already proposed based on seismological, geodetic, and tsunami data. Here, we present comprehensive coseismic slip distribution model based not only on land GPS data but also on seafloor geodetic observations, which are obtained through recent observation cruises. We combined displacements at seafloor sites that are deduced from two different types of seafloor observations with the displacements at land GPS stations. One is the seafloor crustal deformation observation with GPS/Acoustic ranging (GPS/A). Horizontal displacements associated with the 2011 Tohoku earthquake at 2 GPS/A stations are estimated by comparing the station positions deduced from the observations before and after the earthquake. Another type of the seafloor data is seafloor water pressure that is observed by means of ocean bottom pressure gauge (OBP). We analyzed OBP data observed at 2 cabled and 4 self pop-up stations, and estimated vertical displacements due to the main shock. Displacements at 5 GPS/A stations of Japan Coast Guard [Sato et al., 2011, science] are also included to estimate the coseismic slip distribution of the earthquake. Estimated slip distribution of the 2011 Tohoku Earthquake shows following features. 1) The area of large slip ( > 20 m) is about 100 km x 200 km on the plate interface shallower than 30 km in depth. 2) There is no large slip occurred off southern Iwate prefecture on the plate interface throughout shallow to deep. 3) The latitudinal range of the area of large slip almost corresponds to the one of the area of strong interplate coupling zone off Miyagi prefecture. 4) Significant slip is estimated around the rupture area of 1978 M7.4 Miyagi-oki earthquake (40

  14. Interseismic strain accumulation across the North Tabriz Fault (NW Iran) deduced from InSAR time series

    NASA Astrophysics Data System (ADS)

    Karimzadeh, Sadra; Cakir, Ziyadin; Osmanoğlu, Batuhan; Schmalzle, Gina; Miyajima, Masakatsu; Amiraslanzadeh, Reza; Djamour, Yahya

    2013-05-01

    We present the surface deformation along the North Tabriz Fault (NTF) deduced from Synthetic Aperture Radar Interferometry (InSAR) technique. The NTF, a major right-lateral strike-slip fault within the active Arabia-Eurasia collision zone, is located 40-45 km southwest of the Mw 6.5 and Mw 6.3, August 11, 2012 earthquake sequence that caused heavy damage and more than 300 deaths in Ahar, NW Iran. InSAR time series analysis of 17 ENVISAT radar images acquired between 2004 and 2010 using combination of the permanent scatterers InSAR (PSI) and the small baseline InSAR (SBAS) approach reveals sub-centimeter interseismic strain accumulation across the NTF and rapid subsidence in the Tabriz basin. Elastic dislocation modeling of the mean line-of-sight velocity field estimated from SBAS time series yields an average slip rate of 8.7 ± 2.5 mm/year with a locking depth of 15.8 ± 10.8 km. This rate is consistent with previous geodetic estimates based on recent Global Positioning System measurements, and suggests a recurrence interval of 250-300 years for major earthquakes of Mw 7.0-7.3 on the NTF, much shorter than those estimated from paleoseismic investigations (821 ± 176 years). This in turn implies a high seismic potential on the NTF taking into account the occurrence of the two last earthquakes on the NTF in 1721 and 1780. SAR time series analysis also reveals three regions of rapid subsidence with a maximum rate of 20 mm/year near the Tabriz thermal power plant in the Tabriz basin. Piezometric data from groundwater wells suggest that accelerated subsidence over the last several years may result from fluctuations in the ground water table.

  15. Light regulation of cGMP metabolism in toad rod outer segments (ROS) deduced from intact photoreceptor and cellfree kinetics

    SciTech Connect

    Dawis, S.M.; Graeff, R.M.; Heyman, R.A.; Walseth, T.F.; Butz, E.A.

    1987-05-01

    The rate of cGMP hydrolysis by phosphodiesterase (PDE) in intact ROS, monitored in dark-adapted isolated toad retina by the rate of /sup 18/O appearance in guanine nucleotide ..cap alpha..-phosphoryls, is 1/360th of that observed in disrupted ROS at a substrate concentration equivalent to the total (cGMP) in ROS. Low to moderate photic stimuli increase this cGMP hydrolytic rate up to 10-fold in intact ROS with little or no change in total (cGMP). G-protein activation determined in intact ROS by the fraction of GDP labeled with /sup 18/O corresponds with light-related increases in cGMP flux. In contrast, relatively high intensities and extended illumination cause attenuation of maximal cGMP hydrolysis with proportionate reductions in total (cGMP). From these observations combined with the effects of activated G-protein on kinetics and cGMP binding of ROS PDE the following model for light-regulation of cGMP metabolism was deduced: cGMP flux in intact ROS is severely restricted in the dark state because approximately 99% of the cGMP is bound to high affinity sites on the non-stimulated form of PDE. This constraint is relieved when activated G-protein converts the cGMP-binding form of PDE to a high K/sub m/ catalytic form. cGMP is then redistributed to a dynamic pool where it is available to PDE catalytic sites and lower affinity allosteric sites. The (cGMP) in the dynamic pool is maintained or further increased or decreased by modulating the activity of an apparently light-sensitive guanylyl cyclase.

  16. Utilization of metabonomics to identify serum biomarkers in murine H22 hepatocarcinoma and deduce antitumor mechanism of Rhizoma Paridis saponins.

    PubMed

    Qiu, Peiyu; Man, Shuli; Yang, He; Fan, Wei; Yu, Peng; Gao, Wenyuan

    2016-08-25

    Murine H22 hepatocarcinoma model is so popular to be used for the preclinical anticancer candidate's evaluation. However, the metabolic biomarkers of this model were not identified. Meanwhile, Rhizoma Paridis saponins (RPS) as natural products have been found to show strong antitumor activity, while its anti-cancer mechanism is not clear. To search for potential metabolite biomarkers of this model, serum metabonomics approach was applied to detect the variation of metabolite biomarkers and the related metabolism genes and signaling pathway were used to deduce the antitumor mechanisms of RPS. As a result, ten serum metabolites were identified in twenty-four mice including healthy mice, non-treated cancer mice, RPS-treated cancer mice and RPS-treated healthy mice. RPS significantly decreased tumor weight correlates to down-regulating lactate, acetate, N-acetyl amino acid and glutamine signals (p < 0.05), which were marked metabolites screened according to the very important person (VIP), loading plot and receiver operating characteristic curve (ROC) tests. For the analysis of metabolic enzyme related genes, RPS reversed the aerobic glycolysis through activating tumor suppressor p53 and PTEN, and suppressed FASN to inhibit lipogenesis. What's more, RPS repressed Myc and GLS expression and decreased glutamine level. The regulating PI3K/Akt/mTOR and HIF-1α/Myc/Ras networks also participated in these metabolic changes. Taken together, RPS suppressed ATP product made the tumor growth slow, which indicated a good anti-cancer effect and new angle for understanding the mechanism of RPS. In conclusion, this study demonstrated that the utility of (1)H NMR metabolic profiles taken together with tumor weight and viscera index was a promising screening tool for evaluating the antitumor effect of candidates. In addition, RPS was a potent anticancer agent through inhibiting cancer cellular metabolism to suppress proliferation in hepatoma H22 tumor murine, which promoted the

  17. SIMMAX: A modern analog technique to deduce Atlantic sea surface temperatures from planktonic foraminifera in deep-sea sediments

    NASA Astrophysics Data System (ADS)

    Pflaumann, Uwe; Duprat, Josette; Pujol, Claude; Labeyrie, Laurent D.

    1996-02-01

    leave the system.) (Paper 95PA01743,SIMMAX: A modern analog technique to deduce Atlantic sea surfacetemperatures from planktonic foraminifera in deep-sea sediments, UwePflaumann, Josette Duprat, Claude Pujol, and Laurent D. Labeyrie).Diskette may be ordered from American Geophysical Union, 2000Florida Avenue, N.W., Washington, DC 20009; Payment mustaccompany order.

  18. Tables of Neutron-Induced Fission Cross Section for Various Pu, U, and Th Isotopes, Deduced from Measured Fission Probabilites

    SciTech Connect

    Younes, W; Britt, H C

    2003-03-31

    Cross sections for neutron-induced fission of {sup 231,233}Th, {sup 234,235,236,237,239}U, and {sup 240,241,243}Pu are presented in tabular form for incident neutron energies of 0.1 {le} E{sub n}(MeV) {le} 2.5. The cross sections were obtained by converting measured fission probabilities from (t,pf) reactions on mass-A targets to (n,f) cross sections on mass-A + 1 neutron targets, by using modeling to compensate for the differences in the reaction mechanisms. Data from Britt et al. were used for the {sup 234}U(t,pf) reaction, from Cramer et al. for the {sup 230,232}Th(t,pf), {sup 236,238}U(t,pf), and {sup 240,242}Pu(t,pf) reactions, and from Britt et al. for the {sup 233,235}U(t,pf) and {sup 239}Pu(t,pf) reactions. The fission probabilities P{sub (t,pf)}(E{sub x}), measured as a function of excitation energy E{sub x} of the compound system formed by the (t,p) reaction, are listed in the tables with the corresponding deduced cross sections as a function of incident neutron energy E{sub n}, {sigma}{sub (n,f)}(E{sub n}). The excitation energy and incident neutron energy are related by E{sub x} = E{sub n} + B{sub n}, where B{sub n}, where B{sub n} is the neutron binding energy. Comparison with ENDF/B-VI evaluations of the well-measured {sup 234,235,236}U(n,f) and {sup 240,241}Pu(n,f) cross sections confirms the accuracy of the present results within a 10% standard deviation above E{sub n} = 1 MeV. Below E{sub n} = 1 MeV, localized deviations of at most {+-} 20% are observed.

  19. 600 yr High-Resolution Climate Reconstruction of the Atlantic Multidecadal Variability deduced from a Puerto Rican Speleothem

    NASA Astrophysics Data System (ADS)

    Winter, A.; Vieten, R.

    2015-12-01

    A multi-proxy speleothem study tracks the regional hydrological variability in Puerto Rico and highlights its close relation to the Atlantic Multidecadal Oscillation. Our proxy record extends instrumental observations 600 years into the past, and reveals the range of natural hydrologic variability for the region. A detailed interpretation and understanding of the speleothem climate record is achieved by the combination of multi-proxy measurements, thin section petrography, XRD analysis and cave monitoring results. The speleothem was collected in Cueva Larga, a one mile-long cave system that has been monitored since 2012. MC-ICPMS 230Th/U-dating reveals that the speleothem grew constantly over the last 600 years. Trace element ratios (Sr/Ca and Mg/Ca) as well as stable isotope ratios (δ18O and δ13C) elucidate significant changes in atmospheric precipitation at the site. Monthly cave monitoring results demonstrate that the epikarst system responds to multi-annual changes in seepage water recharge. The drip water isotope and trace element composition lack short term or seasonal variability. This hydrological system creates favorable conditions to deduce decadal climate variability from Cueva Larga's climate record. The speleothem time series mimics the most-recently published AMO reconstruction over the last 200 years with a time lag of 10-20 years. The time lag seems to results from slow atmospheric signal transmission through the epikarst but the effect of dating uncertainties cannot be ruled out. Warm SSTs in the North Atlantic are related to drier conditions in Puerto Rico. During times of decreased rainfall a relative increase in prior calcite precipitation seems to be the main process causing increased Mg/Ca trace element ratios. High trace element ratios correlate to higher δ13C values. The increase in both proxies indicates a shift towards time periods of decreased rainfall. Over the past 600 years there are two intervals of increased Mg/Ca and δ13C values

  20. 600 yr High-Resolution Climate Reconstruction of the Atlantic Multidecadal Oscillation deduced from a Puerto Rican Speleothem

    NASA Astrophysics Data System (ADS)

    Vieten, Rolf; Winter, Amos; Scholz, Denis; Black, David; Spoetl, Christoph; Winterhalder, Sophie; Koltai, Gabriella; Schroeder-Ritzrau, Andrea; Terzer, Stefan; Zanchettin, Davide; Mangini, Augusto

    2016-04-01

    A multi-proxy speleothem study tracks the regional hydrological variability in Puerto Rico and highlights its close relation to the Atlantic Multidecadal Oscillation (AMO) describing low-frequency sea-surface temperature (SST) variability in the North Atlantic ocean. Our proxy record extends instrumental observations 600 years into the past, and reveals the range of natural hydrologic variability for the region. A detailed interpretation and understanding of the speleothem climate record is achieved by the combination of multi-proxy measurements, thin section petrography, XRD analysis and cave monitoring results. The speleothem was collected in Cueva Larga, a one mile-long cave system that has been monitored since 2012. MC-ICPMS 230Th/U-dating reveals that the speleothem grew constantly over the last 600 years. Trace element ratios (Sr/Ca and Mg/Ca) as well as stable isotope ratios (δ18O and δ13C) elucidate significant changes in atmospheric precipitation at the site. Monthly cave monitoring results demonstrate that the epikarst system responds to multi-annual changes in seepage water recharge. The drip water isotope and trace element composition lack short term or seasonal variability. This hydrological system creates favorable conditions to deduce decadal climate variability from Cueva Larga's climate record. The speleothem time series mimics the most recent AMO reconstruction over the last 200 years (Svendsen et al., 2014) with a time lag of 10-20 years. The lag seems to results from slow atmospheric signal transmission through the epikarst but the effect of dating uncertainties cannot be ruled out. Warm SSTs in the North Atlantic are related to drier conditions in Puerto Rico. During times of decreased rainfall a relative increase in prior calcite precipitation seems to be the main process causing increased Mg/Ca trace element ratios. High trace element ratios correlate to higher δ13C values. The increase in both proxies indicates a shift towards time

  1. Modular design, application architecture, and usage of a self-service model for enterprise data delivery: The Duke Enterprise Data Unified Content Explorer (DEDUCE)

    PubMed Central

    Horvath, Monica M.; Rusincovitch, Shelley A.; Brinson, Stephanie; Shang, Howard C.; Evans, Steve; Ferranti, Jeffrey M.

    2015-01-01

    Purpose Data generated in the care of patients are widely used to support clinical research and quality improvement, which has hastened the development of self-service query tools. User interface design for such tools, execution of query activity, and underlying application architecture have not been widely reported, and existing tools reflect a wide heterogeneity of methods and technical frameworks. We describe the design, application architecture, and use of a self-service model for enterprise data delivery within Duke Medicine. Methods Our query platform, the Duke Enterprise Data Unified Content Explorer (DEDUCE), supports enhanced data exploration, cohort identification, and data extraction from our enterprise data warehouse (EDW) using a series of modular environments that interact with a central keystone module, Cohort Manager (CM). A data-driven application architecture is implemented through three components: an application data dictionary, the concept of “smart dimensions”, and dynamically-generated user interfaces. Results DEDUCE CM allows flexible hierarchies of EDW queries within a grid-like workspace. A cohort “join” functionality allows switching between filters based on criteria occurring within or across patient encounters. To date, 674 users have been trained and activated in DEDUCE, and logon activity shows a steady increase, with variability between months. A comparison of filter conditions and export criteria shows that these activities have different patterns of usage across subject areas. Conclusions Organizations with sophisticated EDWs may find that users benefit from development of advanced query functionality, complimentary to the user interfaces and infrastructure used in other well-published models. Driven by its EDW context, the DEDUCE application architecture was also designed to be responsive to source data and to allow modification through alterations in metadata rather than programming, allowing an agile response to source

  2. Vertical ozone distribution characteristics deduced from 44,000 re-evaluated Umkehr profiles (1957-2000)

    NASA Astrophysics Data System (ADS)

    Bojkov, R. D.; Kosmidis, E.; DeLuisi, J. J.; Petropavlovskikh, I.; Fioletov, V. E.; Godin, S.; Zerefos, C.

    maximum. The deduced trends above 33km confirm a strong ozone decline since the mid-1970s of over 5% per decade without significant seasonal differences. In the mid-latitude stations, the decline in the 15-24km layer is nearly twice as strong in the winter-spring season but much smaller in the summer and fall. The effect of including 1998 and 1999 years with relatively high total ozone data reduces the overall-declining trend. The trends estimated from alg-99 retrievals are statistically not significantly different from those in WMO 1998a; however, they are stronger by about 1% per decade in the lower stratosphere and thus closer to the estimates by sondes. Comparisons of the integrated ozone loss from the Umkehr measurements with the total ozone changes for the same periods at stations with good records show complete concurrence. The altitude and latitude appearances of the long-term geophysical signals like solar (1-2%) and QBO (2-7%) are investigated.

  3. Origin of platinum-group mineral assemblages in a mantle tectonite at Unst deduced from mineral chemistry and osmium isotopes

    NASA Astrophysics Data System (ADS)

    Badanina, Inna Yu.; Lord, Richard A.; Malitch, Kreshimir N.; Meisel, Thomas C.

    2013-04-01

    assemblage is likely to reflect processes such as in-situ serpentinisation, alteration during emplacement or regional greenschist metamorphism. Whole-rock platinum-group element (PGE) concentrations give negatively sloped chondrite-normalized PGE patterns, typical of podiform chromitite, where refractory PGE (Os, Ir and Ru) prevail over less refractory PGE (Rh, Pt and Pd). The osmium isotope results identify similarly 'unradiogenic' 187Os/188Os values for 'primary' and 'secondary' PGM assemblages (with mean 187Os/188Os values of 0.12419 and 0.12464, respectively), being within uncertainty of the chromitite composition (0.1240±0.0006). This implies that the whole-rock Os isotope budget is largely controlled by laurite-dominant assemblages, supporting the conclusion that the 'secondary' PGM assemblage inherited the subchondritic osmium isotope signature of the 'primary' PGM. No evidence for other source contributions during later thermal events has been observed. The Os-isotope data provide further support for an Enstatite Chondrite Reservoir model for the convective upper mantle as defined by Walker et al. (2002) and are consistent with origin of the complex as a Caledonian ophiolite formed in a supra-subduction zone. This study was supported by Russian Foundation for Basic Research (grant 12-05-01166-a to IYuB) and the Uralian Division of Russian Academy of Sciences (project No 12-P-5-1020). References: Andrews, D.R.A., Brenan, J.M. (2002) Phase-equilibrium constraints on the magmatic origin of laurite and Os-Ir alloy. Can. Mineral. 40, 1705-1716. Walker, R.J., Prichard, H.M., Ishiwatari, A., Pimentel, M. (2002) The osmium isotopic composition of convecting upper mantle deduced from ophiolite chromites. Geochim. Cosmochim. Acta 66, 329-345.

  4. Deducing the magma chamber processes of middle Eocene volcanics, Sivas and Tokat regions; NE Turkey: Insights from clinopyroxene chemistry

    NASA Astrophysics Data System (ADS)

    Göçmengil, Gönenç; Karacık, Zekiye; Genç, Ş. Can; Prelevic, Dejan

    2016-04-01

    Middle Eocene Tokat and Sivas volcanic successions occur within the İzmir-Ankara-Erzincan suture zone. Different models are suggested for the development of the middle Eocene volcanism such as post-collisional, delamination and slab-breakoff models as well as the arc magmatism. In both areas, volcanic units cover all the basement units with a regional disconformity and comprise lavas spanning a compositional range from mainly basalt-basaltic andesite to a lesser amount trachyte. Here, we report mineral chemistry of different basaltic lavas through transect from northern continent (Tokat region, Pontides) to southern continent (Sivas region, Kırşehir block) to deduce the characteristics of the magma chamber processes which are active during the middle Eocene. Basaltic lavas include olivine bearing basalts (Ol-basalt: ± olivine + clinopyroxene + plagioclase); amphibole bearing basaltic andesite (Amp-basaltic andesite: amphibole + clinopyroxene + plagioclase ± biotite) and pyroxene bearing basaltic andesite (Px-basaltic andesite: clinopyroxene + plagioclase). Microlitic, glomeroporphyric and pilotaxitic texture are common. Clinopyroxene phenocrystals (macro ≥ 750 μm and micro ≤300 μm) are common in all three lava series which are investigated by transecting core to rim compositional profiles. They are generally augite and diopside; euhedral to subhedral in shape with oscillatory, normal and reverse zoning patterns. Also, all clinopyroxene phenocrystals are marked by moderately high Mg# (for Ol-basalt: 67-91; avg. 80; Amp-basaltic andesite: 76-83, avg: 80; Px -basaltic andesite 68-95, avg: 81). In Ol-basalt, clinopyroxene phenocrystals show normal zonation (high Mg# cores and low Mg# rims). In Amp-basaltic andesite, clinopyroxenes are generally homogenous in composition with minor variation of Mg# towards the rims. On the contrary, in Px-basaltic andesite, clinopyroxene macro phenocrystals show reverse zonation with the core with low Mg# and the rims with

  5. Modelling Al-4wt.%Cu as-cast structure using equiaxed morphological parameters deduced from in-situ synchrotron X-ray radiography

    NASA Astrophysics Data System (ADS)

    Ahmadein, M.; Wu, M.; Reinhart, G.; Nguyen-Thi, H.; Ludwig, A.

    2016-03-01

    The as-cast structure of laboratory scale Al-4wt.%Cu was numerically calculated using assumed morphological parameters. Two parameters are identified: The shape factor which correlates the growth velocity of dendrite envelope to that of the tip; and the sphericity of the equiaxed envelope or the circularity of the columnar trunk envelope which is required to calculate the averaged species diffusion flux across the envelope. In the present work, the real-time radiographs of equiaxed solidification experiment carried out on Al-4wt.%Cu at the European Synchrotron Radiation Facility are used to track the development of crystal envelope with time. The growth rate of the equivalent circular envelope was correlated to dendrite tip growth velocity to deduce the shape factor. The sphericity of dendrite envelope is estimated over the time. The average of the deduced morphological parameters is applied to the model to predict the as-cast structure. The results were compared to those obtained by using morphological parameters from literature. The predicted phase quantities, columnar-to- equiaxed transition, and macrosegregation exhibited significant dependence on those parameters. The predicted macrosegregation using the experimentally deduced parameters fits better to the measurements.

  6. Banned on Broadway but coming to a theater near you: the captive and rethinking the breadth of American anti-lesbian hostility in the 1920s and '30s.

    PubMed

    Hurewitz, Daniel

    2013-01-01

    While the 1927 Broadway closing of the lesbian-themed play The Captive has been treated as launching the homophobic culture that dominated mid-twentieth-century America, the show actually continued to play in cities around the country. It was regularly greeted by packed houses and critics who scoffed at the reaction in New York. The opposition that did emerge was often generated by publisher William Randolph Hearst, while leading civil libertarians fought against him. This demonstrates that the homophobic policies of the 1920s and '30s were not the product of a deeply homophobic society, but generated by smaller numbers of moralizing entreprenuers. PMID:23316840

  7. Concentrations of carbonyl sulfide and hydrogen cyanide in the free upper troposphere and lower stratosphere deduced from ATMOS/Spacelab 3 infrared solar occultation spectra

    NASA Technical Reports Server (NTRS)

    Zander, R.; Rinsland, C. P.; Russell, J. M., III; Farmer, C. B.; Norton, R. H.

    1988-01-01

    This paper presents the results on the volume mixing ratio profiles of carbonyl sulfide and hydrogen cyanide, deduced from the spectroscopic analysis of IR solar absorption spectra obtained in the occultation mode with the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument during its mission aboard Spacelab 3. A comparison of the ATMOS measurements for both northern and southern latitudes with previous field investigations at low midlatitudes shows a relatively good agreement. Southern Hemisphere volume mixing ratio profiles for both molecules were obtained for the first time, as were the profiles for the Northern Hemisphere covering the upper troposphere and the lower stratosphere simultaneously.

  8. The NADH-binding subunit of the energy-transducing NADH-ubiquinone oxidoreductase of Paracoccus denitrificans: Gene cloning and deduced primary structure

    SciTech Connect

    Xu, Xuemin; Matsuno-Yagi, Akemi; Yagi, Takao )

    1991-07-02

    The NADH dehydrogenase complex isolated from Paracoccus denitrificans is composed of approximately 10 unlike polypeptides and contains noncovalently bound FMN, non-heme iron, and acid-labile sulfide. The NADH-binding subunit of this enzyme complex was identified by direct photoaffinity labeling with ({sup 32}P)NADH. primers were synthesized on the basis of the N-terminal amino acid sequency of this polypeptide, and these primers were used to synthesize an oligonucleotide probe by the polymerase chain reaction. This probe was utilized to isolate the gene encoding the NADH-binding subunit from a genomic library of P. denitrificans. The nucleotide sequence of the gene and the deduced amino acid sequence of the entire NADH-binding subunit were determined. The NADH-binding subunit has 431 amino acid residues and a calculated molecular weight of 47 191. The encoded protein contains a putative NAD(H)-binding and an iron-sulfur cluster-binding consensus sequence. The deduced amino acid sequence of the Paracoccus NADH-binding subunit shows remarkable similarity to the {alpha} subunit of the NAD-linked hydrogenase of Alcaligenes eutrophus H16. When partial DNA sequencing of the regions surrounding the gene encoding the NADH-binding subunit was carried out, sequences homologous to the 24-, 49-, and 75-kDa polypeptides of bovine complex 1 were detected, suggesting that the structural genes of the Paracoccus NADH dehydrogenase complex constitute a gene cluster.

  9. A Hypothesis: Life Initiated from Two Genes, as Deduced from the RNA World Hypothesis and the Characteristics of Life-Like Systems.

    PubMed

    Kawamura, Kunio

    2016-01-01

    RNA played a central role in the emergence of the first life-like system on primitive Earth since RNA molecules contain both genetic information and catalytic activity. However, there are several drawbacks regarding the RNA world hypothesis. Here, I briefly discuss the feasibility of the RNA world hypothesis to deduce the RNA functions that are essential for forming a life-like system. At the same time, I have conducted a conceptual analysis of the characteristics of biosystems as a useful approach to deduce a realistic life-like system in relation to the definition of life. For instance, an RNA-based life-like system should possess enough stability to resist environmental perturbations, by developing a cell-like compartment, for instance. Here, a conceptual viewpoint is summarized to provide a realistic life-like system that is compatible with the primitive Earth environment and the capabilities of RNA molecules. According to the empirical and conceptual analysis, I propose the hypothesis that the first life-like system could have initiated from only two genes. PMID:27490571

  10. Evolutionary Steps in the Emergence of Life Deduced from the Bottom-Up Approach and GADV Hypothesis (Top-Down Approach)

    PubMed Central

    Ikehara, Kenji

    2016-01-01

    It is no doubt quite difficult to solve the riddle of the origin of life. So, firstly, I would like to point out the kinds of obstacles there are in solving this riddle and how we should tackle these difficult problems, reviewing the studies that have been conducted so far. After that, I will propose that the consecutive evolutionary steps in a timeline can be rationally deduced by using a common event as a juncture, which is obtained by two counter-directional approaches: one is the bottom-up approach through which many researchers have studied the origin of life, and the other is the top-down approach, through which I established the [GADV]-protein world hypothesis or GADV hypothesis on the origin of life starting from a study on the formation of entirely new genes in extant microorganisms. Last, I will describe the probable evolutionary process from the formation of Earth to the emergence of life, which was deduced by using a common event—the establishment of the first genetic code encoding [GADV]-amino acids—as a juncture for the results obtained from the two approaches. PMID:26821048

  11. Nuclear Fluxes in Diatomic Molecules Deduced from Pump-Probe Spectra with Spatiotemporal Resolutions down to 5 pm and 200 asec

    NASA Astrophysics Data System (ADS)

    Manz, Jörn; Pérez-Torres, Jhon Fredy; Yang, Yonggang

    2013-10-01

    When molecules move, their nuclei flow. The corresponding quantum observable, i.e., the nuclear flux density, was introduced by Schrödinger in 1926, but until now, it has not been measured. Here the first experimental results are deduced from high-resolution pump-probe measurements of the time-dependent nuclear densities in a vibrating diatomic molecule or molecular ion. The nuclear densities are converted to flux densities by means of the continuity equation. The flux densities are much more sensitive to time-dependent quantum effects than the densities. Applications to the sodium molecule and the deuterium molecular ion unravel four new effects; e.g., at the turns from bond stretch to compression, the flux of the nuclei exhibits multiple changes of directions, from small to large bond lengths, a phenomenon that we call the “quantum accordion.”

  12. Nucleotide sequence of the phosphoglycerate kinase gene from the extreme thermophile Thermus thermophilus. Comparison of the deduced amino acid sequence with that of the mesophilic yeast phosphoglycerate kinase.

    PubMed Central

    Bowen, D; Littlechild, J A; Fothergill, J E; Watson, H C; Hall, L

    1988-01-01

    Using oligonucleotide probes derived from amino acid sequencing information, the structural gene for phosphoglycerate kinase from the extreme thermophile, Thermus thermophilus, was cloned in Escherichia coli and its complete nucleotide sequence determined. The gene consists of an open reading frame corresponding to a protein of 390 amino acid residues (calculated Mr 41,791) with an extreme bias for G or C (93.1%) in the codon third base position. Comparison of the deduced amino acid sequence with that of the corresponding mesophilic yeast enzyme indicated a number of significant differences. These are discussed in terms of the unusual codon bias and their possible role in enhanced protein thermal stability. Images Fig. 1. PMID:3052437

  13. New constraints on the rupture process of the 1999 August 17 Izmit earthquake deduced from estimates of stress glut rate moments

    NASA Astrophysics Data System (ADS)

    Clévédé, E.; Bouin, M.-P.; Bukchin, B.; Mostinskiy, A.; Patau, G.

    2004-12-01

    This paper illustrates the use of integral estimates given by the stress glut rate moments of total degree 2 for constraining the rupture scenario of a large earthquake in the particular case of the 1999 Izmit mainshock. We determine the integral estimates of the geometry, source duration and rupture propagation given by the stress glut rate moments of total degree 2 by inverting long-period surface wave (LPSW) amplitude spectra. Kinematic and static models of the Izmit earthquake published in the literature are quite different from one another. In order to extract the characteristic features of this event, we calculate the same integral estimates directly from those models and compare them with those deduced from our inversion. While the equivalent rupture zone and the eastward directivity are consistent among all models, the LPSW solution displays a strong unilateral character of the rupture associated with a short rupture duration that is not compatible with the solutions deduced from the published models. With the aim of understand this discrepancy, we use simple equivalent kinematic models to reproduce the integral estimates of the considered rupture processes (including ours) by adjusting a few free parameters controlling the western and eastern parts of the rupture. We show that the joint analysis of the LPSW solution and source tomographies allows us to elucidate the scattering of source processes published for this earthquake and to discriminate between the models. Our results strongly suggest that (1) there was significant moment released on the eastern segment of the activated fault system during the Izmit earthquake; (2) the apparent rupture velocity decreases on this segment.

  14. Genetic makeup of the Corynebacterium glutamicum LexA regulon deduced from comparative transcriptomics and in vitro DNA band shift assays.

    PubMed

    Jochmann, Nina; Kurze, Anna-Katharina; Czaja, Lisa F; Brinkrolf, Karina; Brune, Iris; Hüser, Andrea T; Hansmeier, Nicole; Pühler, Alfred; Borovok, Ilya; Tauch, Andreas

    2009-05-01

    The lexA gene of Corynebacterium glutamicum ATCC 13032 was deleted to create the mutant strain C. glutamicum NJ2114, which has an elongated cell morphology and an increased doubling time. To characterize the SOS regulon in C. glutamicum, the transcriptomes of NJ2114 and a DNA-damage-induced wild-type strain were compared with that of a wild-type control using DNA microarray hybridization. The expression data were combined with bioinformatic pattern searches for LexA binding sites, leading to the detection of 46 potential SOS boxes located upstream of differentially expressed transcription units. Binding of a hexahistidyl-tagged LexA protein to 40 double-stranded oligonucleotides containing the potential SOS boxes was demonstrated in vitro by DNA band shift assays. It turned out that LexA binds not only to SOS boxes in the promoter-operator region of upregulated genes, but also to SOS boxes detected upstream of downregulated genes. These results demonstrated that LexA controls directly the expression of at least 48 SOS genes organized in 36 transcription units. The deduced genes encode a variety of physiological functions, many of them involved in DNA repair and survival after DNA damage, but nearly half of them have hitherto unknown functions. Alignment of the LexA binding sites allowed the corynebacterial SOS box consensus sequence TcGAA(a/c)AnnTGTtCGA to be deduced. Furthermore, the common intergenic region of lexA and the differentially expressed divS-nrdR operon, encoding a cell division suppressor and a regulator of deoxyribonucleotide biosynthesis, was characterized in detail. Promoter mapping revealed differences in divS-nrdR expression during SOS response and normal growth conditions. One of the four LexA binding sites detected in the intergenic region is involved in regulating divS-nrdR transcription, whereas the other sites are apparently used for negative autoregulation of lexA expression. PMID:19372162

  15. Guanine nucleotide-binding proteins that enhance choleragen ADP-ribosyltransferase activity: nucleotide and deduced amino acid sequence of an ADP-ribosylation factor cDNA.

    PubMed Central

    Price, S R; Nightingale, M; Tsai, S C; Williamson, K C; Adamik, R; Chen, H C; Moss, J; Vaughan, M

    1988-01-01

    Three (two soluble and one membrane) guanine nucleotide-binding proteins (G proteins) that enhance ADP-ribosylation of the Gs alpha stimulatory subunit of the adenylyl cyclase (EC 4.6.1.1) complex by choleragen have recently been purified from bovine brain. To further define the structure and function of these ADP-ribosylation factors (ARFs), we isolated a cDNA clone (lambda ARF2B) from a bovine retinal library by screening with a mixed heptadecanucleotide probe whose sequence was based on the partial amino acid sequence of one of the soluble ARFs from bovine brain. Comparison of the deduced amino acid sequence of lambda ARF2B with sequences of peptides from the ARF protein (total of 60 amino acids) revealed only two differences. Whether these are cloning artifacts or reflect the existence of more than one ARF protein remains to be determined. Deduced amino acid sequences of ARF, Go alpha (the alpha subunit of a G protein that may be involved in regulation of ion fluxes), and c-Ha-ras gene product p21 show similarities in regions believed to be involved in guanine nucleotide binding and GTP hydrolysis. ARF apparently lacks a site analogous to that ADP-ribosylated by choleragen in G-protein alpha subunits. Although both the ARF proteins and the alpha subunits bind guanine nucleotides and serve as choleragen substrates, they must interact with the toxin A1 peptide in different ways. In addition to serving as an ADP-ribose acceptor, ARF interacts with the toxin in a manner that modifies its catalytic properties. PMID:3135549

  16. Deducing the nature of dark matter from direct and indirect detection experiments in the absence of collider signatures of new physics

    SciTech Connect

    Beltran, Maria; Hooper, Dan; Kolb, Edward W.; Krusberg, Zosia A. C.

    2009-08-15

    Despite compelling arguments that significant discoveries of physics beyond the standard model are likely to be made at the Large Hadron Collider, it remains possible that this machine will make no such discoveries, or will make no discoveries directly relevant to the dark matter problem. In this article, we study the ability of astrophysical experiments to deduce the nature of dark matter in such a scenario. In most dark matter studies, the relic abundance and detection prospects are evaluated within the context of some specific particle physics model or models (e.g., supersymmetry). Here, assuming a single weakly interacting massive particle constitutes the Universe's dark matter, we attempt to develop a model-independent approach toward the phenomenology of such particles in the absence of any discoveries at the Large Hadron Collider. In particular, we consider generic fermionic or scalar dark matter particles with a variety of interaction forms, and calculate the corresponding constraints from and sensitivity of direct and indirect detection experiments. The results may provide some guidance in disentangling information from future direct and indirect detection experiments.

  17. Lateral inhomogeneity deduced from 3-D magnetotelluric modeling around the hypocentral area of the 1984 Western Nagano Prefecture earthquake, central Japan

    NASA Astrophysics Data System (ADS)

    Kasaya, T.; Oshiman, N.

    2004-05-01

    Earthquake swarms have been observed since 1976 in the southeastern region of Mt. Ontake, where the 1984 Western Nagano Prefecture earthquake (M6.8) occurred. Most earthquake swarm activities show a dense distribu-tion in a narrow area and at shallow depths. We have carried out forward 3-D magnetotelluric modeling for the data set observed around the focal region of the earthquake swarms. An initial 3-D image was constructed based on previous 2-D magnetotelluric analysis results. The resistivity structure shows remarkable lateral inhomogeneity: a low resistivity zone is located at shallow depth around the center of the study area and the low resistivity zone is surrounded by a high resistive structure and its shape is about a 4-km cube. This feature agrees well with the distribution of the degree of water saturation deduced from seismic information. Hypocenters of recent seismicity are distributed around an area between the resistivity boundary and the relatively high-resistance region. This fact strongly suggests that earthquakes in the study area are triggered by fluid (water) in the crust.

  18. Low-energy tail of the giant dipole resonance in Mo98 and Mo100 deduced from photon-scattering experiments

    NASA Astrophysics Data System (ADS)

    Rusev, G.; Schwengner, R.; Dönau, F.; Erhard, M.; Grosse, E.; Junghans, A. R.; Kosev, K.; Schilling, K. D.; Wagner, A.; Bečvář, F.; Krtička, M.

    2008-06-01

    Dipole-strength distributions in the nuclides Mo98 and Mo100 up to the neutron-separation energies have been studied in photon-scattering experiments at the bremsstrahlung facility of the Forschungszentrum Dresden-Rossendorf. To determine the dipole-strength distributions up to the neutron-emission thresholds, statistical methods were developed for the analysis of the measured spectra. The measured spectra of scattered photons were corrected for detector response and atomic background by simulations using the code GEANT3. Simulations of γ-ray cascades were performed to correct the intensities of the transitions to the ground state for feeding from higher-lying levels and to determine their branching ratios. The photoabsorption cross sections obtained for Mo98 and Mo100 from the present (γ,γ') experiments are combined with (γ,n) data from literature, resulting in a photoabsorption cross section covering the range from 4 to about 15 MeV of interest for network calculations in nuclear astrophysics. Novel information about the low-energy tail of the giant dipole resonance and its energy dependence is derived. The photoabsorption cross sections deduced from the present photon-scattering experiments are compared with existing data from neutron capture and He3-induced reactions.

  19. Metabolic Switches and Adaptations Deduced from the Proteomes of Streptomyces coelicolor Wild Type and phoP Mutant Grown in Batch Culture*

    PubMed Central

    Thomas, Louise; Hodgson, David A.; Wentzel, Alexander; Nieselt, Kay; Ellingsen, Trond E.; Moore, Jonathan; Morrissey, Edward R.; Legaie, Roxane; Wohlleben, Wolfgang; Rodríguez-García, Antonio; Martín, Juan F.; Burroughs, Nigel J.; Wellington, Elizabeth M. H.; Smith, Margaret C. M.

    2012-01-01

    Bacteria in the genus Streptomyces are soil-dwelling oligotrophs and important producers of secondary metabolites. Previously, we showed that global messenger RNA expression was subject to a series of metabolic and regulatory switches during the lifetime of a fermentor batch culture of Streptomyces coelicolor M145. Here we analyze the proteome from eight time points from the same fermentor culture and, because phosphate availability is an important regulator of secondary metabolite production, compare this to the proteome of a similar time course from an S. coelicolor mutant, INB201 (ΔphoP), defective in the control of phosphate utilization. The proteomes provide a detailed view of enzymes involved in central carbon and nitrogen metabolism. Trends in protein expression over the time courses were deduced from a protein abundance index, which also revealed the importance of stress pathway proteins in both cultures. As expected, the ΔphoP mutant was deficient in expression of PhoP-dependent genes, and several putatively compensatory metabolic and regulatory pathways for phosphate scavenging were detected. Notably there is a succession of switches that coordinately induce the production of enzymes for five different secondary metabolite biosynthesis pathways over the course of the batch cultures. PMID:22147733

  20. Assessment of volatile compound profiles and the deduced sensory significance of virgin olive oils from the progeny of Picual×Arbequina cultivars.

    PubMed

    Pérez, Ana G; de la Rosa, Raúl; Pascual, Mar; Sánchez-Ortiz, Araceli; Romero-Segura, Carmen; León, Lorenzo; Sanz, Carlos

    2016-01-01

    Volatile compounds are responsible for most of the sensory qualities of virgin olive oil and they are synthesized when enzymes and substrates come together as olive fruit is crushed during the industrial process to obtain the oil. Here we have studied the variability among the major volatile compounds in virgin olive oil prepared from the progeny of a cross of Picual and Arbequina olive cultivars (Olea europaea L.). The volatile compounds were isolated by SPME, and analyzed by HRGC-MS and HRGC-FID. Most of the volatile compounds found in the progeny's oil are produced by the enzymes in the so-called lipoxygenase pathway, and they may be clustered into different groups according to their chain length and polyunsaturated fatty acid origin (linoleic and linolenic acids). In addition, a group of compounds derived from amino acid metabolism and two terpenes also contributed significantly to the volatile fraction, some of which had significant odor values in most of the genotypes evaluated. The volatile compound content of the progeny was very varied, widely transgressing the progenitor levels, suggesting that in breeding programs it might be more effective to consider a larger number of individuals within the same cross than using different crosses with fewer individuals. Multivariate analysis allowed genotypes with particularly interesting volatile compositions to be identified and their flavor quality deduced. PMID:26199104

  1. Experimental and data analysis techniques for deducing collision-induced forces from photographic histories of engine rotor fragment impact/interaction with a containment ring

    NASA Technical Reports Server (NTRS)

    Yeghiayan, R. P.; Leech, J. W.; Witmer, E. A.

    1973-01-01

    An analysis method termed TEJ-JET is described whereby measured transient elastic and inelastic deformations of an engine-rotor fragment-impacted structural ring are analyzed to deduce the transient external forces experienced by that ring as a result of fragment impact and interaction with the ring. Although the theoretical feasibility of the TEJ-JET concept was established, its practical feasibility when utilizing experimental measurements of limited precision and accuracy remains to be established. The experimental equipment and the techniques (high-speed motion photography) employed to measure the transient deformations of fragment-impacted rings are described. Sources of error and data uncertainties are identified. Techniques employed to reduce data reading uncertainties and to correct the data for optical-distortion effects are discussed. These procedures, including spatial smoothing of the deformed ring shape by Fourier series and timewise smoothing by Gram polynomials, are applied illustratively to recent measurements involving the impact of a single T58 turbine rotor blade against an aluminum containment ring. Plausible predictions of the fragment-ring impact/interaction forces are obtained by one branch of this TEJ-JET method; however, a second branch of this method, which provides an independent estimate of these forces, remains to be evaluated.

  2. Primary structure of human corticosteroid binding globulin, deduced from hepatic and pulmonary cDNAs, exhibits homology with serine protease inhibitors.

    PubMed Central

    Hammond, G L; Smith, C L; Goping, I S; Underhill, D A; Harley, M J; Reventos, J; Musto, N A; Gunsalus, G L; Bardin, C W

    1987-01-01

    We have isolated and sequenced cDNAs for corticosteroid binding globulin (CBG) prepared from human liver and lung mRNAs. Our results indicate that CBG mRNA is relatively abundant in the liver but is also present in the lung, testis, and kidney. The liver CBG cDNA contains an open reading frame for a 405-amino acid (Mr 45,149) polypeptide. This includes a predominantly hydrophobic, leader sequence of 22 residues that precedes the known NH2-terminal sequence of human CBG. We, therefore, predict that the mature protein is composed of 383 amino acids and is a polypeptide of Mr 42,646. A second, in-frame, 72-base-pair cistron of unknown significance exists between the TAA termination codon for CBG and a possible polyadenylylation signal (AATAAA) located 16 nucleotides before the polyadenylylation site. The deduced amino acid sequence of mature CBG contains two cysteine residues and consensus sequences for the attachment of six possible N-linked oligosaccharide chains. The sequences of the human lung and liver CBG cDNAs differ by only one nucleotide within the proposed leader sequence, and we attribute this to a point mutation. No sequence homology was found between CBG and other steroid binding proteins, but there is a remarkable similarity between the amino acid sequences of CBG and of alpha 1-antitrypsin, and this extends to other members of the serpin (serine protease inhibitor) superfamily. Images PMID:3299377

  3. Excitation of the E2 and W1 "Arched" Filaments Near the Galactic Center as Deduced from Far-Infrared Spectroscopy

    NASA Technical Reports Server (NTRS)

    Colgan, Sean W.J.; Erickson, Edwin F.; Simpson, Janet P.; Haas, Michael R.; Morris, Mark

    1994-01-01

    We present measurements of the far-infrared (FIR) fine structure lines [S III] (33 microns), [Si II] (35 microns), [O III] (51, 88 microns), [O I] (63 microns) and [C II] (158 microns) and the adjacent continua along a scan crossing the E2 and W1 thermal radio filaments in the Galactic center 'Arc'. The deduced electron density and excitation vary along the scan by less than factors of two and three, respectively. The properties of the two filaments are similar: the line and continuum fluxes peak at the radio ridge, and the ridge/off-ridge contrast is greatest for the FIR continuum and ionized lines, lower for the single dish radio measurements (Sofue et al. 1986), and smallest for the low excitation lines. The spatial coincidence of the FIR and radio peaks demonstrates that any excitation mechanism for the radio continuum filaments must also account for the FIR line and continuum emission. The FIR luminosity of approx. 3 x 10(exp 5) Solar Luminosity per beam, and the association of [O III] emission with the filaments poses difficulties for shock and MHD models. Photoionization of molecular cloud edges by a random distribution of stars is the most likely excitation mechanism among those proposed. The continuum and the low excitation line fluxes are consistent with an origin in photodissociated molecular material adjacent to the photoionized gas.

  4. Hemispheric asymmetry in transition from equatorial plasma bubble to blob as deduced from 630.0 nm airglow observations at low latitudes

    NASA Astrophysics Data System (ADS)

    Park, Jaeheung; Martinis, Carlos R.; Lühr, Hermann; Pfaff, Robert F.; Kwak, Young-Sil

    2016-01-01

    Transitions from depletions to enhancements of 630.0 nm nighttime airglow have been observed at Arecibo. Numerical simulations by Krall et al. (2009) predicted that they should occur only in one hemisphere, which has not yet been confirmed observationally. In this study we investigate the hemispheric conjugacy of the depletion-to-enhancement transition using multiple instruments. We focus on one event observed in the American longitude sector on 22 December 2014: 630.0 nm airglow depletions evolved into enhancements in the Northern Hemisphere while the evolution did not occur in the conjugate location in the Southern Hemisphere. Concurrent plasma density measured by low Earth orbit (LEO) satellites and 777.4 nm airglow images support that the depletions and enhancements of 630.0 nm nighttime airglow reflect plasma density decreases and increases (blobs), respectively. Characteristics of the airglow depletions, in the context of the LEO satellite data, further suggest that the plasma density depletion deduced from the airglow data represents equatorial plasma bubbles (EPBs) rather than medium-scale traveling ionospheric disturbances from midlatitudes. Hence, the event in this study can be interpreted as EPB-to-blob transition.

  5. Sequence of cDNA for rat cystathionine gamma-lyase and comparison of deduced amino acid sequence with related Escherichia coli enzymes.

    PubMed Central

    Erickson, P F; Maxwell, I H; Su, L J; Baumann, M; Glode, L M

    1990-01-01

    A cDNA clone for cystathionine gamma-lyase was isolated from a rat cDNA library in lambda gt11 by screening with a monospecific antiserum. The identity of this clone, containing 600 bp proximal to the 3'-end of the gene, was confirmed by positive hybridization selection. Northern-blot hybridization showed the expected higher abundance of the corresponding mRNA in liver than in brain. Two further cDNA clones from a plasmid pcD library were isolated by colony hybridization with the first clone and were found to contain inserts of 1600 and 1850 bp. One of these was confirmed as encoding cystathionine gamma-lyase by hybridization with two independent pools of oligodeoxynucleotides corresponding to partial amino acid sequence information for cystathionine gamma-lyase. The other clone (estimated to represent all but 8% of the 5'-end of the mRNA) was sequenced and its deduced amino acid sequence showed similarity to those of the Escherichia coli enzymes cystathionine beta-lyase and cystathionine gamma-synthase throughout its length, especially to that of the latter. Images Fig. 1. Fig. 2. Fig. 3. Fig. 5. PMID:2201285

  6. Deduced consensus sequence of Sindbis virus strain AR339: mutations contained in laboratory strains which affect cell culture and in vivo phenotypes.

    PubMed Central

    McKnight, K L; Simpson, D A; Lin, S C; Knott, T A; Polo, J M; Pence, D F; Johannsen, D B; Heidner, H W; Davis, N L; Johnston, R E

    1996-01-01

    The consensus sequence of the Sindbis virus AR339 isolate, the prototype alphavirus, has been deduced. THe results presented here suggest (i) that a substantial proportion of the sequence divergence evident between the consensus sequence and sequences of laboratory strains of AR339 has resulted from selection for efficient growth in cell culture, (ii) that many of these changes affect the virulence of the virus in animal models, and (iii) that such modified genetic backgrounds present in laboratory strains can exert a significant influence on genetic studies of virus pathogenesis and host range. A laboratory strain of Sindbis virus AR339 was sequenced and cloned as a cDNA (pTRSB) from which infectious virus (TRSB) could be derived. The consensus sequence was deduced from the complete sequences of pTRSB and HRsp (E. G. Strauss, C. M. Rice, and J. H. Strauss, Virology 133:92-110, 1984), from partial sequences of the glycoprotein genes of three other AR339 laboratory strains, and by comparison with the sequences of the glycoprotein genes of three other AR339 sequence. HRsp differed form the consensus sequence by eight coding changes, and TRSB differed by three coding changes. In the 5' untranslated region, HRsp differed from the consensus sequence at nucleotide (nt) 5. These differences were likely the result of cell culture passage of the original AR339 isolate. At three of the difference loci (one in TRSB and two in HRsp), selection of cell-culture-adaptive mutations was documented with Sindbis virus or other alphaviruses. Selection in cell culture often results in attenuation of virulence in animals. Considering the TRSB and HRsp sequences together, one noncoding difference from the consensus (an A-for-G substitution in the 5' untranslated region at nt 5) and six coding differences in the glycoprotein genes (at E2 amino acids 1, 3, 70, and 172 and at E1 amino acids 72 and 237) were at loci which, either individually or in combination, significantly affected

  7. The application of striation analysis and focal mechanism stress inversion in deducing the kinematic history of faults: Examples from the Bristol Channel UK and the Ionian Zone Greece

    NASA Astrophysics Data System (ADS)

    Melis, Nikolaos S.; Miliorizos, Marios N.; Oshoano Aipoh, Hilary

    2013-04-01

    The present work compliments the application of a methodology, in reviewing and investigating further the kinematic history of faults, based on striation analysis and stress inversion of earthquake focal mechanisms and combines them to refine tectonic modelling and hence improve further hazard assessment. Two areas are chosen for this application: the Bristol Channel, UK and the Ionian Zone, Greece. Striation analysis is carried out in two complementary fault terranes. The first along the northern margin of the Inner Bristol Channel, UK, offers a natural laboratory to study in detail the reactivation history of the inverted Bristol Channel basin; and, the second along the north western coastline of the Ionian Zone, Greece, presents an opportunity to illustrate the relationship between movement of a framework of faults within the external orogenic zone of the Hellenides and the stress deduced from focal mechanisms of earthquakes in the region. The UK example reveals phases of Mesozoic negative inversion of Late Palaeozoic basement frontal and oblique ramp thrust faults, followed by Caenozoic positive inversions of Mesozoic normal and strike slip faults. The Greek example shows an equally composite history of faulting; Tethyan basement strata contain normal faults that pass up sequence and across unconformities into Mesozoic and Caenozoic strata, with thrusts and positively inverted faults recording typical dextral transpression. The fault framework in older strata and the veneers of Recent strata above them display Neotectonic fault histories of sinistral transtension, in addition to the transpression. Since the Ionian Zone lies suitably in the external zone, deformation favours the reactivation of fault lineaments, rather than the genesis of pristine faults. Both examples are used to demonstrate this structural principle. Focal mechanisms of Greek earthquake data are used in stress inversion and the results are applied upon the inherited fault framework and are

  8. Long term carbon dioxide exchange above a mixed forest in the Belgian Ardennes: evaluation of different approaches to deduce total ecosystem respiration from Eddy covariance measurements

    NASA Astrophysics Data System (ADS)

    Jérôme, Elisabeth; Aubinet, Marc; Heinesch, Bernard

    2010-05-01

    The general aim of this research is to analyze inter annual variability of carbon dioxide (CO2) fluxes exchanged by a mixed forest located at the Vielsalm experimental site in Belgium. At this site, CO2 flux measurements started in 1996 and are still going on. Thirteen complete years of measurements are thus available. Net Ecosystem Exchange (NEE) inter annual variability may be driven by gross primary productivity (GPP) or Total Ecosystem Respiration (TER), which should thus be both quantified. Using flux partitioning methods, TER is deduced from NEE measurements. GPP is then obtained by subtracting TER from NEE. Initially, a robust estimation of TER is required. This work seeks to compare two independent approaches to assess TER in order to quantify the implications on inter-annual variability. The comparison was performed on twelve complete years. TER estimates can be deduced by extrapolating to the whole day NEE measurements taken during selected night or day periods. In both case, the extrapolation is performed by using a respiration response to temperature. The first approach, referred as the night-time approach, consisted in calculating TER using a temperature response function derived from night-time data sets (Reichstein et al., 2005). The second approach, referred as the daytime approach, consisted in assessing TER from the intercept of the NEE/Photosynthetically Photon Flux Density (PPFD) response (Wohlfahrt et al., 2005). For each approach, different modalities were compared: the use of long term (annual) or short term (15 days) data sets for the night-time approach and the use of different types of regression for the daytime approach. In addition, the impact of the temperature choice was studied for each of the approaches. For the night-time approach, main results showed that air temperature sensitivity of ecosystem respiration derived from annual data did not reflect the short-term air temperature sensitivity. Vielsalm is a summer active ecosystem

  9. The integration of gravity, magnetic and seismic data in delineating the sedimentary basins of northern Sinai and deducing their structural controls

    NASA Astrophysics Data System (ADS)

    Selim, El Sayed Ibrahim

    2016-01-01

    The Sinai Peninsula is a part of the Sinai sub-plate that located between the southeast Nubian-Arabian shield and the southeastern Mediterranean northward. The main objectives of this investigation are to deduce the main sedimentary basin and its subdivisions, identify the subsurface structural framework that affects the study area and determine the thickness of sedimentary cover of the basement surface. The total intensity magnetic map, Bouguer gravity map and seismic data were used to achieve the study aims. Structural interpretation of the gravity and magnetic data were done by applying advanced processing techniques. These techniques include; Reduce to the pole (RTP), Power spectrum, Tile derivative and Analytical Signal techniques were applied on gravity and magnetic data. Two dimensional gravity and magnetic modeling and interpretation of seismic sections were done to determine the thickness of sedimentary cover of the study area. The integration of our interpretation suggests that, the northern Sinai area consists of elongated troughs that contain many high structural trends. Four major structural trends have been identified, that, reflecting the influence of district regional tectonic movements. These trends are: (1) NE-SW trend; (2) NNW-SSE trend; (3) ENE-WSW trend and (4) WNW-ESE trend. There are also many minor trends, E-W, NW-SE and N-S structural trends. The main sedimentary basin of North Sinai is divided into four sub-basins; (1) Northern Maghara; (2) Northeastern Sinai; (3) Northwestern Sinai and (4) Central Sinai basin. The sedimentary cover ranges between 2 km and 7 km in the northern part of the study area.

  10. How to deduce and teach the logical and unambiguous answer, namely L = ∑C, to "What is Life?" using the principles of communication?

    PubMed

    De Loof, Arnold

    2015-01-01

    Is it possible to understand the very nature of 'Life' and 'Death' based on contemporary biology? The usual spontaneous reaction is: "No way. Life is far too complicated. It involves both material- and an immaterial dimensions, and this combination exceeds the capacities of the human brain." In this paper, a fully contrarian stand is taken. Indeed it will be shown that without invoking any unknown principle(s) unambiguous definitions can be logically deduced. The key? First ask the right questions. Next, thoroughly imbue contemporary biology with the principles of communication, including both its 'hardware' and its 'software' aspects. An integrative yet simple principle emerges saying that: 1. All living matter is invariably organized as sender-receiver compartments that incessantly handle and transfer information (= communicate); 2. The 'communicating compartment' is better suited to serve as universal unit of structure, function and evolution than 'the (prokaryotic) cell', the smallest such unit; 3. 'Living matter' versus 'non-living' are false opposites while 'still alive' and 'just not alive anymore' are true opposites; 4. 'Death' ensues when a given sender-receiver compartment irreversibly loses its ability to handle information at its highest level of compartmental organization; 5. The verb 'Life' (L) denotes nothing else than the total sum (∑) of all acts of communication (C) executed by a sender-receiver at all its levels of compartmental organization: L = ∑C; 6. Any act of communication is a problem-solving act; 6. Any Extended Evolutionary Synthesis (EES) should have the definition of Life at its core. PMID:27064373

  11. How to deduce and teach the logical and unambiguous answer, namely L = ∑C, to “What is Life?” using the principles of communication?

    PubMed Central

    De Loof, Arnold

    2015-01-01

    Is it possible to understand the very nature of ‘Life’ and ‘Death’ based on contemporary biology? The usual spontaneous reaction is: “No way. Life is far too complicated. It involves both material- and an immaterial dimensions, and this combination exceeds the capacities of the human brain.” In this paper, a fully contrarian stand is taken. Indeed it will be shown that without invoking any unknown principle(s) unambiguous definitions can be logically deduced. The key? First ask the right questions. Next, thoroughly imbue contemporary biology with the principles of communication, including both its ‘hardware’ and its ‘software’ aspects. An integrative yet simple principle emerges saying that: 1. All living matter is invariably organized as sender-receiver compartments that incessantly handle and transfer information (= communicate); 2. The ‘communicating compartment’ is better suited to serve as universal unit of structure, function and evolution than ‘the (prokaryotic) cell’, the smallest such unit; 3. ‘Living matter’ versus ‘non-living’ are false opposites while ‘still alive’ and ‘just not alive anymore’ are true opposites; 4. ‘Death’ ensues when a given sender-receiver compartment irreversibly loses its ability to handle information at its highest level of compartmental organization; 5. The verb ‘Life’ (L) denotes nothing else than the total sum (∑) of all acts of communication (C) executed by a sender-receiver at all its levels of compartmental organization: L = ∑C; 6. Any act of communication is a problem-solving act; 6. Any Extended Evolutionary Synthesis (EES) should have the definition of Life at its core. PMID:27064373

  12. Variation in aspects of cysteine proteinase catalytic mechanism deduced by spectroscopic observation of dithioester intermediates, kinetic analysis and molecular dynamics simulations.

    PubMed

    Reid, J D; Hussain, S; Sreedharan, S K; Bailey, T S; Pinitglang, S; Thomas, E W; Verma, C S; Brocklehurst, K

    2001-07-15

    The possibility of a slow post-acylation conformational change during catalysis by cysteine proteinases was investigated by using a new chromogenic substrate, N-acetyl-Phe-Gly methyl thionoester, four natural variants (papain, caricain, actinidin and ficin), and stopped-flow spectral analysis to monitor the pre-steady state formation of the dithioacylenzyme intermediates and their steady state hydrolysis. The predicted reversibility of acylation was demonstrated kinetically for actinidin and ficin, but not for papain or caricain. This difference between actinidin and papain was investigated by modelling using QUANTA and CHARMM. The weaker binding of hydrophobic substrates, including the new thionoester, by actinidin than by papain may not be due to the well-known difference in their S2-subsites, whereby that of actinidin in the free enzyme is shorter due to the presence of Met211. Molecular dynamics simulation suggests that during substrate binding the sidechain of Met211 moves to allow full access of a Phe sidechain to the S2-subsite. The highly anionic surface of actinidin may contribute to the specificity difference between papain and actinidin. During subsequent molecular dynamics simulations the P1 product, methanol, diffuses rapidly (over<8 ps) out of papain and caricain but 'lingers' around the active centre of actinidin. Uniquely in actinidin, an Asp142-Lys145 salt bridge allows formation of a cavity which appears to constrain diffusion of the methanol away from the catalytic site. The cavity then undergoes large scale movements (over 4.8 A) in a highly correlated manner, thus controlling the motions of the methanol molecule. The changes in this cavity that release the methanol might be those deduced kinetically. PMID:11439083

  13. Variation in aspects of cysteine proteinase catalytic mechanism deduced by spectroscopic observation of dithioester intermediates, kinetic analysis and molecular dynamics simulations.

    PubMed Central

    Reid, J D; Hussain, S; Sreedharan, S K; Bailey, T S; Pinitglang, S; Thomas, E W; Verma, C S; Brocklehurst, K

    2001-01-01

    The possibility of a slow post-acylation conformational change during catalysis by cysteine proteinases was investigated by using a new chromogenic substrate, N-acetyl-Phe-Gly methyl thionoester, four natural variants (papain, caricain, actinidin and ficin), and stopped-flow spectral analysis to monitor the pre-steady state formation of the dithioacylenzyme intermediates and their steady state hydrolysis. The predicted reversibility of acylation was demonstrated kinetically for actinidin and ficin, but not for papain or caricain. This difference between actinidin and papain was investigated by modelling using QUANTA and CHARMM. The weaker binding of hydrophobic substrates, including the new thionoester, by actinidin than by papain may not be due to the well-known difference in their S2-subsites, whereby that of actinidin in the free enzyme is shorter due to the presence of Met211. Molecular dynamics simulation suggests that during substrate binding the sidechain of Met211 moves to allow full access of a Phe sidechain to the S2-subsite. The highly anionic surface of actinidin may contribute to the specificity difference between papain and actinidin. During subsequent molecular dynamics simulations the P1 product, methanol, diffuses rapidly (over<8 ps) out of papain and caricain but 'lingers' around the active centre of actinidin. Uniquely in actinidin, an Asp142-Lys145 salt bridge allows formation of a cavity which appears to constrain diffusion of the methanol away from the catalytic site. The cavity then undergoes large scale movements (over 4.8 A) in a highly correlated manner, thus controlling the motions of the methanol molecule. The changes in this cavity that release the methanol might be those deduced kinetically. PMID:11439083

  14. Molecular cloning and expression of partial cDNAs and deduced amino acid sequence of a carboxyl-terminal fragment of human apolipoprotein B-100.

    PubMed Central

    Wei, C F; Chen, S H; Yang, C Y; Marcel, Y L; Milne, R W; Li, W H; Sparrow, J T; Gotto, A M; Chan, L

    1985-01-01

    Apolipoprotein (apo) B-100 cDNAs were identified in a human liver cDNA library cloned in the expression vector lambda gt11. The beta-galactosidase-apoB-100 fusion protein was detected by two independently produced low density lipoprotein polyclonal antisera and by three apoB-100 monoclonal antibodies that crossreact with apoB-74. It was not recognized by two apoB-100 monoclonal antibodies that crossreact with apoB-26. The longest clone, lambda B8, was completely sequenced. It contains a 2.8-kilobase DNA fragment containing the codons for the carboxyl-terminal 836 amino acid residues of apo-B-100, as well as the 3' untranslated region of apoB-100 mRNA. We have thus mapped apoB-74 to the carboxyl-terminal portion of apoB-100. The deduced amino acid sequence of the cloned DNA matches the sequences of 14 apoB-100 peptides determined in our laboratory. Minor differences in amino acid sequence were noted in three of the peptides, suggesting polymorphism of apoB-100 at the protein and DNA levels. Secondary structure predictions reveal an unusual pattern for apolipoproteins, consisting of beta-structure (24%), alpha-helical content (33%), and random structure (30%). Ten amphipathic helical regions of 10-24 residues were identified. This carboxyl-terminal fragment of apoB-100 is considerably more hydrophobic than other apolipoproteins with known structure. Its lipid binding regions might include stretches of highly hydrophobic beta-sheets as well as amphipathic helices. Our findings on apoB structure might be important for understanding the role of apoB-100-containing lipoproteins in atherosclerosis. PMID:2932736

  15. Nucleotide and deduced amino acid sequences of the nucleocapsid protein of the virulent A75/17-CDV strain of canine distemper virus.

    PubMed

    Stettler, M; Zurbriggen, A

    1995-05-01

    Virus persistence is essential in the chronic inflammatory canine distemper virus (CDV)-induced demyelinating disease. In the case of CDV there is a close association between persistence and virulence. Virulent CDV isolated from dogs with distemper shows immediate persistence in primary dog brain cell cultures (DBCC) and in different cell lines. We have evidence that the nucleocapsid (NP) protein plays an important role in the development of persistence. The NP-protein, the most abundant structural virus protein, also influences virus assembly and has some regulatory functions in virus transcription and replication. In this study we compared the nucleotide and deduced amino acid sequence of a virulent CDV strain (A75/17-CDV) to a culture-attenuated non-virulent strain (OP-CDV). Viral RNA was extracted from DBCC infected with virulent CDV. Virulent CDV retains its in vivo properties, such as virulence and ability to cause demyelination, when propagated in these DBCC. The viral RNA was reverse transcribed and the resulting cDNA amplified by polymerase chain reaction for subsequent cloning. The nucleotide sequences of these clones were determined by the dideoxy chain termination method. The number of nucleotides and the putative NP-protein of the virulent strain matched the attenuated CDV strain. We observed a total of 105 nucleotide differences. Three were localised within the 3' and five within the 5' non-coding region of the NP-gene. The 97 nucleotide changes within the coding region resulted in 22 amino acid differences. 10 of these amino acid (AA) modifications were within the N-terminal region (AA 1 to 159) and 12 within the C-terminal area (AA 351 to 523).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8588315

  16. Cross-linking of initiation factor IF3 to Escherichia coli 30S ribosomal subunit by trans-diamminedichloroplatinum(II): characterization of two cross-linking sites in 16S rRNA; a possible way of functioning for IF3.

    PubMed Central

    Ehresmann, C; Moine, H; Mougel, M; Dondon, J; Grunberg-Manago, M; Ebel, J P; Ehresmann, B

    1986-01-01

    The initiation factor IF3 is platinated with trans-diamminedichloroplatinum(II) and cross-linked to Escherichia coli 30S ribosomal subunit. Two cross-linking sites are unambiguously identified on the 16S rRNA: a major one, in the region 819-859 in the central domain, and a minor one, in the region 1506-1529 in the 3'-terminal domain. Specific features of these sequences together with their particular location within the 30S subunit lead us to postulate a role for IF3, that conciliates topographical and functional observations made so far. Images PMID:2425339

  17. H2rs: Deducing evolutionary and functionally important residue positions by means of an entropy and similarity based analysis of multiple sequence alignments

    PubMed Central

    2014-01-01

    Background The identification of functionally important residue positions is an important task of computational biology. Methods of correlation analysis allow for the identification of pairs of residue positions, whose occupancy is mutually dependent due to constraints imposed by protein structure or function. A common measure assessing these dependencies is the mutual information, which is based on Shannon’s information theory that utilizes probabilities only. Consequently, such approaches do not consider the similarity of residue pairs, which may degrade the algorithm’s performance. One typical algorithm is H2r, which characterizes each individual residue position k by the conn(k)-value, which is the number of significantly correlated pairs it belongs to. Results To improve specificity of H2r, we developed a revised algorithm, named H2rs, which is based on the von Neumann entropy (vNE). To compute the corresponding mutual information, a matrix A is required, which assesses the similarity of residue pairs. We determined A by deducing substitution frequencies from contacting residue pairs observed in the homologs of 35 809 proteins, whose structure is known. In analogy to H2r, the enhanced algorithm computes a normalized conn(k)-value. Within the framework of H2rs, only statistically significant vNE values were considered. To decide on significance, the algorithm calculates a p-value by performing a randomization test for each individual pair of residue positions. The analysis of a large in silico testbed demonstrated that specificity and precision were higher for H2rs than for H2r and two other methods of correlation analysis. The gain in prediction quality is further confirmed by a detailed assessment of five well-studied enzymes. The outcome of H2rs and of a method that predicts contacting residue positions (PSICOV) overlapped only marginally. H2rs can be downloaded from http://www-bioinf.uni-regensburg.de. Conclusions Considering substitution frequencies

  18. Evidence of different ocean responses to atmospheric pressurevariations in the Atlantic, Indian and Pacific Basins as deduced fromERS-2 altimetric data

    NASA Astrophysics Data System (ADS)

    Gómez-Enri, J.; Villares, P.; Bruno, M.; Catalán, M.

    2004-02-01

    . The exponential increase in the use of altimeter data in oceanographic studies in the past two decades has improved the knowledge of the processes that govern the interaction between the ocean and the atmosphere. One of these processes is the response of the ocean to atmospheric pressure variations, which has been deeply analysed in the past. That response is based on the isostatic assumption used to establish a standard correction for altimetric purposes, the Inverse Barometer Correction (IBC). As a general rule, the ocean goes up/down 1cm when the atmospheric pressure goes down/up 1mbar. However, in light of recent works in some oceanic regions, discrepancies arise when the real response is compared to the hypothetical one. It is important to quantify this discrepancy, in order to improve the accuracy of the correction, which is one of the most significant geophysical corrections applied to altimeter records. Some aspects of this response remain unclear, such as the real space-temporal scales where IBC can be applied, the influence of wind, non-isostatic atmospheric pressure-driven signals, and the effect of aliasing from high frequency signals. This paper is an attempt to gain insight into this phenomenon. The data used are the residuals obtained between sea surface heights from the ERS-2 altimeter and the outputs of a global barotropic ocean model. Significant departures from the hypothetical isostatic response in all data series (spatial and temporal domain) have been found, especially in the case of altimeter records. By applying the collinear track method, we observe that the estimated Atlantic Ocean response is quite similar to the one deduced from the isostatic assumption at all latitudinal bands. Nonetheless, the Indian and Pacific Oceans show important departures from the hypothetical value at low latitudes. Results obtained with the crossover track method show important deviations at low latitudes in the three basins. In order to understand why the

  19. Impact delivery of organic matter on the acapulcoite-lodranite parent-body deduced from C, N isotopes and nanostructures of carbon phases in Acapulco and Lodran

    NASA Astrophysics Data System (ADS)

    Charon, E.; Aléon, J.; Rouzaud, J.-N.

    2014-10-01

    Lodran. Carbon phases in Lodran would have been formed by the secondary carbonization of hydrocarbon fluids released during the primary carbonization of IOM. In the framework of this model, the C isotopic compositions can be reproduced using Rayleigh distillation at each carbonization step and the N isotopic compositions can be understood as resulting from the variable loss and preservation of 15N-rich nitriles (δ15N ∼ +800‰) and 15N-poor pyrroles (δ15N = -140‰) during carbonization. The combined interpretation of the temperatures deduced from this model, petrographic cooling rates, and thermochronological indicators suggest that the CI-CM IOM could have been introduced in the parent-body by an impact, about 10 Myr after solar system formation.

  20. The Na(+)-translocating ATPase of Acetobacterium woodii is a F1F0-type enzyme as deduced from the primary structure of its beta, gamma and epsilon subunits.

    PubMed

    Forster, A; Daniel, R; Müller, V

    1995-05-10

    A 4.5 kbp EcoRI fragment hybridizing to a fragment of uncD (coding for subunit beta of F1F0-ATPases) was cloned from chromosomal DNA of Acetobacterium woodii. The nucleotide sequence was determined and revealed five open reading frames (ORF), four of which were identified to code for subunits of the Na(+)-ATPase. The deduced amino acid sequences of these ORF's are homologous to subunit alpha (partial coding sequence, C-terminal end), gamma, beta and epsilon of F1F0-ATPases from various organisms; furthermore, the organization of the genes in the order uncA (alpha), uncG (gamma), uncD (beta), uncC (epsilon) is identical to the structure of unc operon as present in most bacteria. Downstream of uncC is an ORF whose deduced amino acid sequence has 53% sequence homology to AlgD from Pseudomonas aeruginosa. The structure and organization of the unc genes are the final proof that the Na(+)-ATPase from A. woodii is a member of the family of F1F0-ATPases. PMID:7748890

  1. On a Riesz basis of exponentials related to the eigenvalues of an analytic operator and application to a non-selfadjoint problem deduced from a perturbation method for sound radiation

    SciTech Connect

    Ellouz, Hanen; Feki, Ines; Jeribi, Aref

    2013-11-15

    In the present paper, we prove that the family of exponentials associated to the eigenvalues of the perturbed operator T(ε) ≔ T{sub 0} + εT{sub 1} + ε{sup 2}T{sub 2} + … + ε{sup k}T{sub k} + … forms a Riesz basis in L{sup 2}(0, T), T > 0, where ε∈C, T{sub 0} is a closed densely defined linear operator on a separable Hilbert space H with domain D(T{sub 0}) having isolated eigenvalues with multiplicity one, while T{sub 1}, T{sub 2}, … are linear operators on H having the same domain D⊃D(T{sub 0}) and satisfying a specific growing inequality. After that, we generalize this result using a H-Lipschitz function. As application, we consider a non-selfadjoint problem deduced from a perturbation method for sound radiation.

  2. Deducing dust emission mechanisms from field measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field observations are needed to both develop and test theories on dust emission for use in global modeling systems. The mechanism of dust emission (aerodynamic entrainment, saltation bombardment, aggregate disintegration) and the amount and particle-size distribution of emitted dust may vary under ...

  3. Long-term changes in UT/LS ozone between the late 1970s and the 1990s deduced from the GASP and MOZAIC aircraft programs and from ozonesondes

    NASA Astrophysics Data System (ADS)

    Schnadt Poberaj, C.; Staehelin, J.; Brunner, D.; Thouret, V.; de Backer, H.; Stübi, R.

    2009-01-01

    We present ozone measurements of the Global Atmospheric Sampling Program (GASP) performed from four commercial and one research aircraft in the late 1970s to compare them with respective measurements of the ongoing MOZAIC project. Climatologies of UT/LS ozone were built using the aircraft data sets (1975-1979 and 1994-2001), and long-term changes between the 1970s and 1990s were derived by comparison. The data were binned relative to the dynamical tropopause to separate between UT and LS air masses. LS data were analysed using equivalent latitudes. In the UT, pronounced increases are found over the Middle East and South Asia in the spring and summer seasons. Increases are also found over Japan, Europe, and the eastern parts of the Unites States depending on season. LS ozone over northern mid- and high latitudes was found to be lower in the 1990s compared to the 1970s in all seasons of the year. In addition, a comparison with long-term changes deduced from ozonesondes is presented. An altitude offset was applied to the sonde data to account for the slow response time of the ozone sensors. The early 1970s European Brewer-Mast (BM) sonde data agree with GASP within the range of uncertainty (UT) or measured slightly less ozone (LS). In contrast, the 1990s BM sensors show consistently and significantly higher UT/LS ozone values than MOZAIC. This unequal behaviour of aircraft/sonde comparisons in the 1970s and 1990s leads to differences in the estimated long-term changes over Europe: while the comparison between GASP and MOZAIC indicates ozone changes of -5% to 10% over Europe, the sondes suggest a much larger increase of 10%-35% depending on station and season, although statistical significance is not conclusive due to data sample limitations. In contrast to the BM sondes, the Electrochemical Cell (ECC) sonde at Wallops Island, USA, measured higher UT ozone than both GASP and MOZAIC. Hence, long-term changes from GASP/MOZAIC agree within the range of uncertainty with

  4. Long-term changes in UT/LS ozone between the late 1970s and the 1990s deduced from the GASP and MOZAIC aircraft programs and from ozonesondes

    NASA Astrophysics Data System (ADS)

    Schnadt Poberaj, C.; Staehelin, J.; Brunner, D.; Thouret, V.; de Backer, H.; Stübi, R.

    2009-07-01

    We present ozone measurements of the Global Atmospheric Sampling Program (GASP) performed from four commercial and one research aircraft in the late 1970s to compare them with respective measurements of the ongoing MOZAIC project. Multi-annual averages of UT/LS ozone were built using the aircraft data sets (1975-1979 and 1994-2001), and long-term changes between the 1970s and 1990s were derived by comparison. The data were binned relative to the dynamical tropopause to separate between UT and LS air masses. LS data were analysed using equivalent latitudes. In the UT, pronounced increases of 20-40% are found over the Middle East and South Asia in the spring and summer seasons. Increases are also found over Japan, Europe, and the eastern parts of the United States depending on season. LS ozone over northern mid- and high latitudes was found to be lower in the 1990s compared to the 1970s in all seasons of the year. In addition, a comparison with long-term changes deduced from ozonesondes is presented. The early 1970s European Brewer-Mast (BM) sonde data agree with GASP within the range of uncertainty (UT) or measured slightly less ozone (LS). In contrast, the 1990s BM sensors show consistently and significantly higher UT/LS ozone values than MOZAIC. This unequal behaviour of aircraft/sonde comparisons in the 1970s and 1990s leads to differences in the estimated long-term changes over Europe: while the comparison between GASP and MOZAIC indicates ozone changes of -5% to 10% over Europe, the sondes suggest a much larger increase of 10%-35% depending on station and season, although statistical significance is not conclusive due to data sample limitations. In contrast to the BM sondes, the Electrochemical Cell (ECC) sonde at Wallops Island, USA, measured higher UT ozone than both GASP and MOZAIC. Hence, long-term changes from GASP/MOZAIC agree within the range of uncertainty with the changes deduced from Wallops Island.

  5. Density functional theory-based simulations of sum frequency generation spectra involving methyl stretching vibrations: effect of the molecular model on the deduced molecular orientation and comparison with an analytical approach

    NASA Astrophysics Data System (ADS)

    Cecchet, F.; Lis, D.; Caudano, Y.; Mani, A. A.; Peremans, A.; Champagne, B.; Guthmuller, J.

    2012-03-01

    The knowledge of the first hyperpolarizability tensor elements of molecular groups is crucial for a quantitative interpretation of the sum frequency generation (SFG) activity of thin organic films at interfaces. Here, the SFG response of the terminal methyl group of a dodecanethiol (DDT) monolayer has been interpreted on the basis of calculations performed at the density functional theory (DFT) level of approximation. In particular, DFT calculations have been carried out on three classes of models for the aliphatic chains. The first class of models consists of aliphatic chains, containing from 3 to 12 carbon atoms, in which only one methyl group can freely vibrate, while the rest of the chain is frozen by a strong overweight of its C and H atoms. This enables us to localize the probed vibrational modes on the methyl group. In the second class, only one methyl group is frozen, while the entire remaining chain is allowed to vibrate. This enables us to analyse the influence of the aliphatic chain on the methyl stretching vibrations. Finally, the dodecanethiol (DDT) molecule is considered, for which the effects of two dielectrics, i.e. n-hexane and n-dodecane, are investigated. Moreover, DDT calculations are also carried out by using different exchange-correlation (XC) functionals in order to assess the DFT approximations. Using the DFT IR vectors and Raman tensors, the SFG spectrum of DDT has been simulated and the orientation of the methyl group has then been deduced and compared with that obtained using an analytical approach based on a bond additivity model. This analysis shows that when using DFT molecular properties, the predicted orientation of the terminal methyl group tends to converge as a function of the alkyl chain length and that the effects of the chain as well as of the dielectric environment are small. Instead, a more significant difference is observed when comparing the DFT-based results with those obtained from the analytical approach, thus indicating

  6. Evaluation of Little Ice Age cooling in Western Central Andes, suggested by paleoELAs, in contrast with global warming since late 19th century deduced from instrumental records

    NASA Astrophysics Data System (ADS)

    Ubeda, Jose; Palacios, David; Campos, Néstor; Giraldez, Claudia; García, Eduardo; Quiros, Tatiana

    2015-04-01

    This paper attempts to evaluate climate cooling (°C) during the glacial expansion phases using the product GTV•ΔELA, where GTV is the vertical air temperature gradient (°C/m) and ΔELA (m) the difference in level observed between the Equilibrium Line Altitude (ELA) reconstructions for current and past glaciers. With this aim the Area x Altitude Balance Ratio-(AABR) method was used to produce reconstructions of present ELAs (2002-2010) and paleoELAs corresponding to the last glacier advance phase. The reconstructions were produced in three study areas located along a N-S transect of the western cordillera in the Central Andes: the south-western sector of the Nevado Hualcán (9°S, 77°W; Giráldez 2011); the southern slope of the Cordillera Pariaqaqa (12°S, 76°W; Quirós, 2013) and the NW, NE, SE and SW quadrants of the Nevado Coropuna (16°S, 72°W; García 2013; Úbeda 2011; Campos, 2012). The three mountains exceed 6000 m altitude, their summit areas are covered by glaciers, and on their slopes there are existing well-conserved moraines deposited by the last advances near the present front of the ice masses. Although there are no absolute dates to confirm this hypothesis, it has been assumed that the last glacial advances occurred during the Little Ice Age (LIA), which the oxygen isotopes of the Nevado Huascarán (9°S, 77°W) date to the period 1500-1890. For the Hualcán and Pariaqaqa the mean global value of the Earth's GTV (6.5°C/km) was used, considered valid for the Tropics. On the Coropuna a GTV=8.4°C/km was used, based on high resolution sensors installed in situ since 2007 (Úbeda 2011). This gradient is approaching the upper limit of the dry adiabatic gradient (9.8°C/km), as the Coropuna region is more arid than the other case study areas. The climate cooling estimates deduced from the product GTV•ΔELA were compared with the global warming shown by the 1880-2012 series, ΔT=0.85°C, and 1850/1900-2003/2012, ΔT=0.78°C. The differences are

  7. Dual colour fluorescence in situ hybridization to paraffin-embedded samples to deduce the presence of the der(X)t(X;18)(p11.2;q11.2) and involvement of either the SSX1 or SSX2 gene: a diagnostic and prognostic aid for synovial sarcoma.

    PubMed

    Lu, Y J; Birdsall, S; Summersgill, B; Smedley, D; Osin, P; Fisher, C; Shipley, J

    1999-03-01

    Identification of the t(X;18)(p11.2;q11.2) and the fusion gene products, SYT-SSX1 and SYT-SSX2, associated with a high proportion of synovial sarcomas, has been shown to be a useful diagnostic aid. This study demonstrates the application of dual colour fluorescence in situ hybridization to paraffin-embedded samples to deduce the presence of the derivative X chromosome and also the position of the breakpoint on chromosome X at either the SSX1 or the SSX2 gene. This used region specific markers from chromosomes X and 18 and an optimized protocol involving microwave exposure. Novel and rapid scoring criteria were validated which circumvented potential problems of nuclear truncation and defining cell boundaries. This involved blind analysis of two negative sarcoma samples and three synovial sarcomas in which corresponding frozen material had been previously shown to have the translocation involving different SSX genes. Six new cases diagnosed as synovial sarcoma were also analysed; two monophasic and two biphasic case were deduced to have a breakpoint in the SSX1 gene, one monophasic case an SSX2 breakpoint, and one case did not show rearrangement of the region. The ability to analyse formalin-fixed, paraffin-embedded samples in this way has practical implications for aiding the diagnosis of difficult cases, recently ascribed prognostic relevance, and allows further retrospective studies to be carried out. The methodology is also applicable to the identification of other tumour specific translocations in paraffin-embedded material. PMID:10398111

  8. Preliminary results on interstellar reddening as deduced from filter photometry

    NASA Technical Reports Server (NTRS)

    Laget, M.

    1972-01-01

    Filter photometry has been used to derive the interstellar reddening law from stars through the study of a single spectral type, B0. The deficiency in the far ultraviolet flux of a supergiant relative to a main sequence star is compared with the difference in the flux distribution due to a change of one spectral class. Individual interstellar reddening curves show the general feature reported by Stecher (1969) and by Bless and Savage (1970). There is a large amount of scatter in the far ultraviolet which may be partially due to a real difference in interstellar extinction and partially due to observational inaccuracy.

  9. Clusterization of water molecules as deduced from statistical mechanical approach

    NASA Astrophysics Data System (ADS)

    Krasnoholovets, Volodymyr

    2004-12-01

    Using the methods of statistical mechanics we have shown that a homogeneous water network is unstable and spontaneously disintegrates to the nonhomogeneous state (i.e. peculiar clusters), which can be treated as an ordinary state of liquid water. The major peculiarity of the concept is that it separates the paired potential into two independent components—the attractive potential and the repulsive one, which in turn should feature a very different dependence on the distance from the particle (a water molecule in the present case). We choose the interaction potential as a combination of the ionic crystal potential and the vibratory potential associated with the elastic properties of the water system as a whole. The number ℵ of water molecules that enters a cluster is calculated as a function of several parameters, such as the dielectric constant, the mass of a water molecule, the distance between nearest molecules, and the vibrations of nearest molecules in their nodes. The number of H2O molecules that comprise a cluster is estimated as about ℵ ≈ 900, which agrees with the available experimental data.

  10. Inter-relationships of haplosporidians deduced from ultrastructural studies.

    PubMed

    Hine, P M; Carnegie, R B; Burreson, E M; Engelsma, M Y

    2009-02-25

    We reviewed papers reporting haplosporidian ultrastructure to compare inter-relationships based on ultrastructure with those based on molecular data, to identify features that may be important in haplosporidian taxonomy, and to consider parasite taxonomy in relation to host taxonomy. There were links between the following: (1) the plasmodia of an abalone parasite, Haplosporidium nelsoni and Urosporidium crescens in the release of haplosporosomes; (2) H. costale and H. armoricanum in haplosporosome shape and presence and shape of Golgi in spores; (3) basal asporous crustacean haplosporidians which form haplosporosomes from formative bodies (FBs) in vegetative stages--H. nelsoni, which forms haplosporosomes from FBs in plasmodial cytoplasm, and H. louisiana, Minchinia spp. and Bonamia perspora, which form haplosporosomes from FBs in spores; (4) crustacean haplosporidians, Bonamia spp. and M. occulta in the predominance of uni- and binucleate stages; and (5) lipid-like vesicles in sporoplasms of H. costale, H. armoricanum, H. lusitanicum, H. pickfordi, H. montforti, and B. perspora. In general, these relationships reflect phylogenies based on molecular studies. As well as spore form and ornamentation, haplosporogenesis in spores appears to be taxonomically important. Parasite and host taxonomy were linked in the infection of lower invertebrates by Urosporidium spp., the infection of oysters by Bonamia spp., and of molluscs by Minchinia spp. Haplosporidium spp. are patently an artificial, paraphyletic group probably comprising many taxa. Consequently, the taxonomy of haplosporidians needs a thorough revision. PMID:19402456

  11. Deducing Electron Properties from Hard X-Ray Observations

    NASA Technical Reports Server (NTRS)

    Kontar, E. P.; Brown, J. C.; Emslie, A. G.; Hajdas, W.; Holman, G. D.; Hurford, G. J.; Kasparova, J.; Mallik, P. C. V.; Massone, A. M.; McConnell, M. L.; Piana, M.; Prato, M.; Schmahl, E. J.; Suarez-Garcia, E.

    2011-01-01

    X-radiation from energetic electrons is the prime diagnostic of flare-accelerated electrons. The observed X-ray flux (and polarization state) is fundamentally a convolution of the cross-section for the hard X-ray emission process(es) in question with the electron distribution function, which is in turn a function of energy, direction, spatial location and time. To address the problems of particle propagation and acceleration one needs to infer as much information as possible on this electron distribution function, through a deconvolution of this fundamental relationship. This review presents recent progress toward this goal using spectroscopic, imaging and polarization measurements, primarily from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Previous conclusions regarding the energy, angular (pitch angle) and spatial distributions of energetic electrons in solar flares are critically reviewed. We discuss the role and the observational evidence of several radiation processes: free-free electron-ion, free-free electron-electron, free-bound electron-ion, photoelectric absorption and Compton backscatter (albedo), using both spectroscopic and imaging techniques. This unprecedented quality of data allows for the first time inference of the angular distributions of the X-ray-emitting electrons and improved model-independent inference of electron energy spectra and emission measures of thermal plasma. Moreover, imaging spectroscopy has revealed hitherto unknown details of solar flare morphology and detailed spectroscopy of coronal, footpoint and extended sources in flaring regions. Additional attempts to measure hard X-ray polarization were not sufficient to put constraints on the degree of anisotropy of electrons, but point to the importance of obtaining good quality polarization data in the future.

  12. Climate change deduced from isotopes in tree rings

    SciTech Connect

    Pendall, E.G.; Leavitt, S.W.

    1997-11-01

    This paper describes the theory of carbon, hydrogen, and oxygen isotopic signatures in cellulose for the purpose of paleoclimatic reconstruction. Mechanisms governing tree ring cellulose isotopic variability are investigated, and applications to the southwestern United States are delineated. A monitoring program of pinyon trees and comparison to climatic parameters is briefly described. Variables measured included deviations in hydrogen and oxygen-18 isotopic composition in precipitation, soil water, stem and leaf water, and atmospheric vapor. Water from phloem tissue was found to be isotopically identical to the xylem sap, suggesting that cellulose precursors can exchange isotopically with source water before cellulose is made in the trunk, thus removing most of the isotopic signal from the leaves. Overall results suggest that, on arid sites in the southwestern US receiving adequate summer rain, a precipitation seasonality signal may be recorded. 21 refs., 2 figs.

  13. Deducing Electron Properties from Hard X-ray Observations

    NASA Astrophysics Data System (ADS)

    Kontar, E. P.; Brown, J. C.; Emslie, A. G.; Hajdas, W.; Holman, G. D.; Hurford, G. J.; Kašparová, J.; Mallik, P. C. V.; Massone, A. M.; McConnell, M. L.; Piana, M.; Prato, M.; Schmahl, E. J.; Suarez-Garcia, E.

    2011-09-01

    X-radiation from energetic electrons is the prime diagnostic of flare-accelerated electrons. The observed X-ray flux (and polarization state) is fundamentally a convolution of the cross-section for the hard X-ray emission process(es) in question with the electron distribution function, which is in turn a function of energy, direction, spatial location and time. To address the problems of particle propagation and acceleration one needs to infer as much information as possible on this electron distribution function, through a deconvolution of this fundamental relationship. This review presents recent progress toward this goal using spectroscopic, imaging and polarization measurements, primarily from the Reuven Ramaty High Energy Solar Spectroscopic Imager ( RHESSI). Previous conclusions regarding the energy, angular (pitch angle) and spatial distributions of energetic electrons in solar flares are critically reviewed. We discuss the role and the observational evidence of several radiation processes: free-free electron-ion, free-free electron-electron, free-bound electron-ion, photoelectric absorption and Compton backscatter (albedo), using both spectroscopic and imaging techniques. This unprecedented quality of data allows for the first time inference of the angular distributions of the X-ray-emitting electrons and improved model-independent inference of electron energy spectra and emission measures of thermal plasma. Moreover, imaging spectroscopy has revealed hitherto unknown details of solar flare morphology and detailed spectroscopy of coronal, footpoint and extended sources in flaring regions. Additional attempts to measure hard X-ray polarization were not sufficient to put constraints on the degree of anisotropy of electrons, but point to the importance of obtaining good quality polarization data in the future.

  14. Deducing the multi-trader population driving a financial market

    NASA Astrophysics Data System (ADS)

    Gupta, Nachi; Hauser, Raphael; Johnson, Neil

    2005-12-01

    We have previously laid out a basic framework for predicting financial movements and pockets of predictability by tracking the distribution of a multi-trader population playing on an artificial financial market model. This work explores extensions to this basic framework. We allow for more intelligent agents with a richer strategy set, and we no longer constrain the distribution over these agents to a probability space. We then introduce a fusion scheme which accounts for multiple runs of randomly chosen sets of possible agent types. We also discuss a mechanism for bias removal on the estimates.

  15. Magmatic Processes and Systems Deduced from Single Crystals

    NASA Astrophysics Data System (ADS)

    Davidson, J.; Bezard, R. C.; Morgan, D. J.; Ginibre, C.

    2014-12-01

    When crystals grow in liquids the composition of their outermost layer will reflect that of the host with which they are in equilibrium and will therefore record the liquid composition, pressure and temperature.. Following separation from their sources, magmas differentiate. This change in liquid composition is driven largely by crystallisation in response to cooling or decompression. Other open system processes such as mixing and contamination are common. These can lead to abrupt changes in trace element and isotopic composition, accompanied by petrographic features, such as dissolution surfaces or zones of melt inclusions. Where such careful mineral-scale studies have been performed, the prevalence of open system processes is clear. In many cases these are shown by core-rim isotopic variations. Crystal-scale compositional variations in the context of whole rock compositions and petrography have allowed us to show crustal assimilation even from regions of supposedly oceanic crust such as the Lesser Antilles. In tandem with tracking magma evolution, core-rim analyses of appropriate crystals have also provided diffusion profiles which reflect timescales of magmatic processes. A key point, long recognised by Bruce Marsh, is that in situ geochemical data should be considered in a petrographic context in order to gain the most (and most credible) insights on the workings of magma systems from hand specimen to whole volcano/pluton scales: The petrographic microscope is not dead yet Identification of magmatic processes from in situ scrutiny allows us to synthesise the architectures and inner workings of magma systems. The evidence for interaction among magmas in many systems is compelling and suggests that many exist as stacked dike-sill arrangements with wall-rock focussed crystal growth and mush zones. These are consistent with many of the systematics suggested some time ago by Bruce Marsh

  16. Emission region size deduced from the AKR dynamical spectrum

    NASA Astrophysics Data System (ADS)

    Schreiber, R.

    2003-04-01

    Simple 3D ray tracing based on Calvert's (1981) formulas has been applied to the modeling of the AKR dynamical spectrum observed during the 20 minutes polar pass of FAST satellite (orbit 1761). General shape of the spectrum can be produced by AKR emission region spread along the auroral oval. Its longitudinal (MLT) and latitudinal (Invariant Latitude) dimensions correspond to the +/- 1 hour and +/- 2 degrees extent with respect to the FAST satellite source crossing position. Varying frequency boundaries of bright patches seen in the dynamical spectrum put the limit on the rays escape angles at the AKR source region. Escape angles measured with respect to the upward direction parallel to the magnetic field at the source region are confined within 60 - 90 degrees range.

  17. The laws of thermodynamics deduced from statistical mechanics

    NASA Astrophysics Data System (ADS)

    Diu, B.; Guthmann, C.; Lederer, D.; Roulet, B.

    Since the advent of statistical mechanics, the laws of thermodynamics are consequences of more fundamental postulates. Nevertheless, the logical link between statistical mechanics and thermodynamics is far from being precisely described in the literature, at an elementary level. The present paper tries to clarify this subject. It is necessary to recall some basic notions and results of statistical mechanics, but also the main definitions concerning thermodynamic transformations (which are partly ignored in too many cases). The laws of thermodynamics, especially the second one, are then derived and analyzed in statistical terms, and the statistical meaning of heat and work is discussed. Depuis l'avènement de la mécanique statistique, les principes de la thermodynamique sont des conséquences de postulats plus fondamentaux. Pourtant, le lien logique entre mécanique statistique et thermodynamique est loin d'etre explicité de façon précise, à un niveau élémentaire, dans la littérature. L'article que voici tente de clarifier le sujet. Il s'avère nécessaire de rappeler quelques notions et résultats de base en mécanique statistique, mais aussi les principales définitions (trop souvent ignorées pour certaines d'entre elles) relatives aux transformations thermodynamiques. Les principes de la thermodynamique, en particulier le second, sont ensuite démontrés et analysés en termes statistiques, et l'interprétation statistique de la chaleur et du travail est discutée.

  18. Tracer transport by the diabatic circulation deduced from satellite observations

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Kiehl, J. T.; Garcia, R. R.; Grose, W.

    1986-01-01

    Nimbus-7 sensor data were used to track the diabatic circulation in the stratosphere to study the advective transport of CH4 and N2O as tracer species. Advective transport by the mean circulation was found to be a function of the temperature field and associated deviations from radiative equilibrium. A photochemical model was applied to account for the disappearance of the tracer species from the stratosphere. Comparisons between the SAMS data and modeling on the basis of the chemical loss rates of the tracers and the LIMS circulation data showed that the model predictions underestimated the resident abundances, although the global distributions and circulations exhibited a good match.

  19. Hazard estimation deduced from GPS and seismic data of Egypt

    NASA Astrophysics Data System (ADS)

    Sayed Mohamed, Abdel-Monem

    Egypt rapidly growing development is accompanied by increasing levels of standard living particular in its urban areas. However, there is a limited experience in quantifying the sources of risk management in Egypt and in designing efficient strategies to keep away serious impacts of earthquakes. From the historical point of view and recent instrumental records, there are some seismo-active regions in Egypt, where some significant earthquakes had occurred in different places. The special tectonic features in Egypt: Aswan, Greater Cairo, Red Sea and Sinai Peninsula regions are the territories of a high seismic risk, which have to be monitored by up-to date technologies. The investigations of the seismic events and interpretations led to evaluate the seismic hazard for disaster prevention and for the safety of the dense populated regions and the vital national projects as the High Dam. In addition to the monitoring of the recent crustal movements, the most powerful technique of satellite geodesy GPS are used where geodetic networks are covering such seismo-active regions. The results from the data sets are compared and combined in order to determine the main characteristics of the deformation and hazard estimation for specified regions. The final compiled output from the seismological and geodetic analysis threw lights upon the geodynamical regime of these seismo-active regions and put Aswan and Greater Cairo under the lowest class according to horizontal crustal strains classifications. This work will serve a basis for the development of so-called catastrophic models and can be further used for catastrophic risk management. Also, this work is trying to evaluate risk of large catastrophic losses within the important regions including the High Dam, strategic buildings and archeological sites. Studies on possible scenarios of earthquakes and losses are a critical issue for decision making in insurance as a part of mitigation measures.

  20. Vegetation density as deduced from ERTS-1 MSS response

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L.; Gausman, H. W.; Cuellar, J. A.; Gerbermann, A. H.; Richardson, A. J.

    1974-01-01

    Reflectance from vegetation increases with increasing vegetation density in the 0.75- to 1.35 micron wavelength interval. Therefore, ERTS-1 bands 6 (0.7 to 0.8 micron) and 7 (0.8 to 1.1 micron) contain information that should relate to the probable yield of crops and the animal carrying capacity of rangeland. The results of an experiment designed specifically to test the relations among leaf area index (LAI), plant population, plant cover and plant height, and the ERTS-1 MSS responses for 3 corn, 10 sorghum, and 10 cotton fields are given. Plant population was as useful as LAI for characterizing the sorghum and corn fields, and plant height was as good as LAI for characterizing cotton fields. These findings generally support the utility of ERTS-1 data for explaining variability in green biomass, harvestable forage and other indicators of productivity.

  1. Deducing the symmetry of helical assemblies: Applications to membrane proteins.

    PubMed

    Coudray, Nicolas; Lasala, Ralph; Zhang, Zhening; Clark, Kathy M; Dumont, Mark E; Stokes, David L

    2016-08-01

    Helical reconstruction represents a convenient and powerful approach for structure determination of macromolecules that assemble into helical arrays. In the case of membrane proteins, formation of tubular crystals with helical symmetry represents an attractive alternative, especially when their small size precludes the use of single-particle analysis. An essential first step for helical reconstruction is to characterize the helical symmetry. This process is often daunting, due to the complexity of helical diffraction and to the low signal-to-noise ratio in images of individual assemblies. Furthermore, the large diameters of the tubular crystals produced by membrane proteins exacerbates the innate ambiguities that, if not resolved, will produce incorrect structures. In this report, we describe a set of tools that can be used to eliminate ambiguities and to validate the choice of symmetry. The first approach increases the signal-to-noise ratio along layer lines by incoherently summing data from multiple helical assemblies, thus producing several candidate indexing schemes. The second approach compares the layer lines from images with those from synthetic models built with the various candidate schemes. The third approach uses unit cell dimensions measured from collapsed tubes to distinguish between these candidate schemes. These approaches are illustrated with tubular crystals from a boron transporter from yeast, Bor1p, and a β-barrel channel from the outer membrane of E. coli, OmpF. PMID:27255388

  2. Shell structure of potassium isotopes deduced from their magnetic moments

    NASA Astrophysics Data System (ADS)

    Papuga, J.; Bissell, M. L.; Kreim, K.; Barbieri, C.; Blaum, K.; De Rydt, M.; Duguet, T.; Garcia Ruiz, R. F.; Heylen, H.; Kowalska, M.; Neugart, R.; Neyens, G.; Nörtershäuser, W.; Rajabali, M. M.; Sánchez, R.; Smirnova, N.; Somà, V.; Yordanov, D. T.

    2014-09-01

    Background: Ground-state spins and magnetic moments are sensitive to the nuclear wave function, thus they are powerful probes to study the nuclear structure of isotopes far from stability. Purpose: Extend our knowledge about the evolution of the 1/2+ and 3/2+ states for K isotopes beyond the N =28 shell gap. Method: High-resolution collinear laser spectroscopy on bunched atomic beams. Results: From measured hyperfine structure spectra of K isotopes, nuclear spins, and magnetic moments of the ground states were obtained for isotopes from N =19 up to N =32. In order to draw conclusions about the composition of the wave functions and the occupation of the levels, the experimental data were compared to shell-model calculations using SDPF-NR and SDPF-U effective interactions. In addition, a detailed discussion about the evolution of the gap between proton 1d3/2 and 2s1/2 in the shell model and ab initio framework is also presented. Conclusions: The dominant component of the wave function for the odd-A isotopes up to K45 is a π1d3/2-1 hole. For K47,49, the main component originates from a π2s1/2-1 hole configuration and it inverts back to the π1d3/2-1 in K51. For all even-A isotopes, the dominant configuration arises from a π1d3/2-1 hole coupled to a neutron in the ν1f7/2 or ν2p3/2 orbitals. Only for K48, a significant amount of mixing with π2s1/2-1⊗ν(pf) is observed leading to a Iπ=1- ground state. For K50, the ground-state spin-parity is 0- with leading configuration π1d3/2-1⊗ν2p3/2-1.

  3. High-latitude irregularity spectra deduced from scintillation measurements

    SciTech Connect

    Wernik, A.W.; Gola, M.; Liu, C.H.; Franke, S.J. Illinois Univ., Urbana )

    1990-10-01

    High-latitude scintillation data show that the strength and spectral index of intensity scintillation are dependent on the propagation geometry. It is shown here that anisotropic irregularity spectra, with different indices along and across the magnetic field, lead to geometrical effects similar to those observed. In general, the spectrum along the magnetic field is steeper than that across the field, and the difference is more pronounced for nighttime conditions. Spectral anisotropy can be interpreted as a size-dependent irregularity anisotropy. It is found that large-scale irregularities in the daytime and nighttime ionosphere are almost isotropic, while small-scale irregularities are anisotropic and considerably more so at night than during the day. It is shown that anisotropic irregularity spectra could account for the observed scintillation and in situ temporal spectra with frequency-dependent slope. 26 refs.

  4. Deducing protein function by forensic integrative cell biology.

    PubMed

    Earnshaw, William C

    2013-12-01

    Our ability to sequence genomes has provided us with near-complete lists of the proteins that compose cells, tissues, and organisms, but this is only the beginning of the process to discover the functions of cellular components. In the future, it's going to be crucial to develop computational analyses that can predict the biological functions of uncharacterised proteins. At the same time, we must not forget those fundamental experimental skills needed to confirm the predictions or send the analysts back to the drawing board to devise new ones. PMID:24358025

  5. Transport of trace species deduced from LIMS observations

    NASA Technical Reports Server (NTRS)

    Gille, J. C.; Lyjak, L. V.; Smith, A. K.; Bailey, P. L.; Massie, S. T.; Smythe, C. M.

    1985-01-01

    One of the critical problems in the middle atmosphere at this time is understanding the interaction between atmospheric motions and photochemistry, and the way in which these two processes maintain the distributions of photochemically active species such as ozone. Recent work has shown that a great deal can be learned by considering the zonally averaged distributions and transports, i.e., working in the latitude-altitude plane. This 2-dimensional approach has been used in the past in Eulerian formation. Recent work (DUNKERTON, 1978) has shown that formulating the transport problems in terms of the residual mean circulation, which has similarity to the Lagrangian mean motion, results in a more physical picture of the way in which the transport takes place. Here, data from the Limb Infrared Monitor of the Stratosphere (LIMB) experiment are used to investigate how well the residual mean formulation works with real data, in the sense of asking how well the predicted ozone changes match those in regions of the lower stratosphere in which chemical changes may be neglected. This allows a test of the approximations that are made, and of the strengths and weaknesses of this approach to transport calculation.

  6. Physical properties of conventional explosives deduced from radio frequency emissions

    SciTech Connect

    Harlin, Jeremiah D; Nemzek, Robert

    2008-01-01

    Los Alamos National Laboratory collected broadband radio frequency (RF) electric field change measurements from multiple detonations of high explosives (HE). Three types of HE were used: small cylinders of flake TNT, solid TNT, and PBX-9501. Low frequency signals (<80 MHz) were shot-to-shot repeatable and occurred within the first 100 {mu} s at measured amplitudes of about 2 V m{sup -1} at 35 m distance. High frequency signals (>290 MHz) occurred later, were an order of magnitude lower in signal strength, and were not repeatable. There is a positive correlation between the maximum electric field change and the shock velocity of the HE. The amount of free charge produced in the explosion estimated from the first RF pulse is between 10 and 150 {mu} C. This implies a weakly ionized plasma with temperatures between 2600 and 2900 K.

  7. Deducing effective light transport parameters in optically thin systems

    NASA Astrophysics Data System (ADS)

    Mazzamuto, G.; Pattelli, L.; Toninelli, C.; Wiersma, D. S.

    2016-02-01

    We present an extensive Monte Carlo study on light transport in optically thin slabs, addressing both axial and transverse propagation. We systematically characterize diffusive transport in this intermediate scattering regime, notably in terms of the spatial variance of the transmitted/reflected profile. Focusing on late, multiply scattered light, we test the validity of the prediction cast by diffusion theory that the spatial variance should grow independently of absorption and, to a first approximation, of the sample thickness and refractive index contrast. Based on a large set of simulated data, we build a freely available look-up table routine enabling reliable and precise determination of the microscopic transport parameters starting from robust observables which are independent from absolute intensity measurements. We also present the Monte Carlo software package that was developed for the purpose of this study.

  8. Deducing chemical structure from crystallographically determined atomic coordinates

    PubMed Central

    Bruno, Ian J.; Shields, Gregory P.; Taylor, Robin

    2011-01-01

    An improved algorithm has been developed for assigning chemical structures to incoming entries to the Cambridge Structural Database, using only the information available in the deposited CIF. Steps in the algorithm include detection of bonds, selection of polymer unit, resolution of disorder, and assignment of bond types and formal charges. The chief difficulty is posed by the large number of metallo-organic crystal structures that must be processed, given our aspiration that assigned chemical structures should accurately reflect properties such as the oxidation states of metals and redox-active ligands, metal coordination numbers and hapticities, and the aromaticity or otherwise of metal ligands. Other complications arise from disorder, especially when it is symmetry imposed or modelled with the SQUEEZE algorithm. Each assigned structure is accompanied by an estimate of reliability and, where necessary, diagnostic information indicating probable points of error. Although the algorithm was written to aid building of the Cambridge Structural Database, it has the potential to develop into a general-purpose tool for adding chemical information to newly determined crystal structures. PMID:21775812

  9. Asteroidal Differentiation Processes Deduced from Ultramafic Achondrite Ureilite Meteorites

    NASA Technical Reports Server (NTRS)

    Downes, Hilary; Mittlefehldt, David W.; Hudson, Pierre; Romanek, Christopher S.; Franchi, Ian

    2006-01-01

    Ureilites are the second largest achondrite group. They are ultramafic achondrites that have experienced igneous processing whilst retaining some degree of nebula-derived chemical heterogeneity. They differ from other achondrites in that they contain abundant carbon and their oxygen isotope compositions are very heterogeneous and similar to those of the carbonaceous chondrite anhydrous mineral line. Their carbonaceous nature and some compositional characteristics indicative of nebular origin suggest that they are primitive materials that form a link between nebular processes and early periods of planetesimal accretion. However, despite numerous studies, the exact origin of ureilites remains unclear. Current opinion is that they represent the residual mantle of an asteroid that underwent silicate and Fe-Ni-S partial melting and melt removal. Recent studies of short-lived chronometers indicate that the parent asteroid of the ureilites differentiated very early in the history of the Solar System. Therefore, they contain important information about processes that formed small rocky planetesimals in the early Solar System. In effect, they form a bridge between nebula processes and differentiation in small planetesimals prior to accretion into larger planets and so a correct interpretation of ureilite petrogenesis is essential for understanding this critical step.

  10. Debris and meteoroid proportions deduced from impact crater residue analysis

    NASA Technical Reports Server (NTRS)

    Berthoud, Lucinda; Mandeville, Jean-Claude; Durin, Christian; Borg, Janet

    1995-01-01

    This study is a further investigation of space-exposed samples recovered from the LDEF satellite and the Franco-Russian 'Aragatz' dust collection experiment on the Mir Space Station. Impact craters with diameters ranging from 1 to 900 micron were found on the retrieved samples. Elemental analysis of residues found in the impact craters was carried out using Energy Dispersive X-ray spectrometry (EDX). The analyses show evidence of micrometeoroid and orbital debris origins for the impacts. The proportions of these two components vary according to particle size and experimental position with respect to the leading edge of the spacecraft. On the LDEF leading edge 17 percent of the impacts were apparently caused by micrometeoroids and 11 percent by debris; on the LDEF trailing edge 23 percent of the impacts are apparently caused by micrometeoroids and 4 percent consist of debris particles - mostly larger than 3 micron in diameter - in elliptical orbits around the Earth. For Mir, the analyses indicate that micrometeoroids form 23 percent of impacts and debris 9 percent. However, we note that 60-70 percent of the craters are unidentifiable, so the definitive proportions of natural v. man-made particles are yet to be determined. Experiments carried out using a light gas gun to accelerate glass spheres and fragments demonstrate the influence of particle shape on crater morphology. The experiments also show that it is more difficult to analyze the residues produced by an irregular fragment than those produced by a spherical projectile. If the particle is travelling above a certain velocity, it vaporizes upon impact and no residues are left. Simulation experiments carried out with an electrostatic accelerator indicate that this limit is about 14 km/s for Fe particles impacting Al targets. This chemical analysis cut-off may bias interpretations of the relative populations of meteoroid and orbital debris. Oblique impacts and multiple foil detectors provide a higher likelihood of detection of residues as the velocities involved are lower.

  11. Deducing a Canopy Reduction Factor for Biogenic Emission Modeling

    NASA Astrophysics Data System (ADS)

    Karl, T.; Guenther, A.

    2005-12-01

    The IPCC 2001 report states that "there is a serious discrepancy between the isoprene emissions derived by [Guenther et al., 1995] based on a global scaling of emission" . and "highlights a key uncertainty in global modeling of highly reactive trace gases: namely, what fraction of primary emissions escapes immediate reaction/removal in the vegetation canopy or immediate boundary layer and participates in the chemistry on the scales represented by global models?". A recent modeling study [Makar et al., 1999] suggested that up to 40 % of isoprene can be lost due to in-canopy chemistry. However, up to date only limited experimental datasets have been used to constrain canopy reduction factors (CRF) . Based on our recent CELTIC (Chemistry, Emission, Loss and Transformation in Canopies) initiative we measured VOC emissions above tropical, deciduous and evergreen ecosystems. In this paper we infer a new parameterization for modeling a CRF due to chemically short-lived biogenic compounds of the form: CRF = h/(a x u* x tau +h) (h: canopy height [m], u*: friction velocity [m/s], tau: lifetime [s], a: dimensionless fitting parameter a=1.5 +/- 0.1). This parameterization is based on results obtained during recent field studies in combination with a random walk model. For isoprene we find that the CRF is on the order of 2-5 % for typical daytime conditions. Loss rates for isoprene are somewhat smaller but within the range of previously reported values [Strong et al., 2004], [Stroud et al., 2005]. Many reactive terpenoid compounds (such as beta-caryophellene) with lifetimes on the order of minutes can be substantially reduced (e.g. up to 60-80 %) before they escape the forest canopy. References: Guenther, A., C.N. Hewitt, D. Erickson, and R. Fall, A global model of natural volatile organic compound emissions, Journal of geophysical research, 100 (D/5), 8873-8892, 1995. Makar, P., J. Fuentes, D. Wang, R. Staebler, and H. Wiebe, Chemical processing of biogenic hydrocarbons within and above a temperate deciduous forest, J. geophys. res., 104 (D3), 3581-3603, 1999. Strong, C., J.D. Fuentes, and D. Baldocchi, Reactive hydrocarbon flux footprints during canopy senescence, Agricultural and Forest Meteorology, 127 (3-4), 159-173, 2004. Stroud, C., P.A. Makar, T. Karl, A. Guenther, C. Geron, A.A. Turnipseed, E. Nemitz, B. Baker, M. Potosnak, J.D. Fuentes, H. McCarthy, and R. Oren, Role of Canopy-Scale Photochemistry in Modifying Biogenic-Atmosphere Exchange of Reactive Terpene Species: Results from the CELTIC Field Study, Journal of Geophysical Research-Atmospheres, in press, 2005.

  12. A Single 30-s Stretch Is Sufficient to Inhibit Maximal Voluntary Strength

    ERIC Educational Resources Information Center

    Winchester, Jason B.; Nelson, Arnold G.; Kokkonen, Joke

    2009-01-01

    While it has been well established that an acute stretching program can inhibit maximal muscle performance, the amount of stretching needed to produce the deleterious response is unknown. Therefore this study examined the dose-response relationship between acute stretching and strength inhibition. Eighteen college students performed a one…

  13. Protein-RNA Dynamics in the Central Junction Control 30S Ribosome Assembly.

    PubMed

    Baker, Kris Ann; Lamichhane, Rajan; Lamichhane, Tek; Rueda, David; Cunningham, Philip R

    2016-09-11

    Interactions between ribosomal proteins (rproteins) and ribosomal RNA (rRNA) facilitate the formation of functional ribosomes. S15 is a central domain primary binding protein that has been shown to trigger a cascade of conformational changes in 16S rRNA, forming the functional structure of the central domain. Previous biochemical and structural studies in vitro have revealed that S15 binds a three-way junction of helices 20, 21, and 22, including nucleotides 652-654 and 752-754. All junction nucleotides except 653 are highly conserved among the Bacteria. To identify functionally important motifs within the junction, we subjected nucleotides 652-654 and 752-754 to saturation mutagenesis and selected and analyzed functional mutants. Only 64 mutants with greater than 10% ribosome function in vivo were isolated. S15 overexpression complemented mutations in the junction loop in each of the partially active mutants, although mutations that produced inactive ribosomes were not complemented by overexpression of S15. Single-molecule Förster or fluorescence resonance energy transfer (smFRET) was used to study the Mg(2+)- and S15-induced conformational dynamics of selected junction mutants. Comparison of the structural dynamics of these mutants with the wild type in the presence and absence of S15 revealed specific sequence and structural motifs in the central junction that are important in ribosome function. PMID:27192112

  14. Low Temperature Physics at Yale in the late 30's through the early 50's

    NASA Astrophysics Data System (ADS)

    Wheeler, Robert

    2006-03-01

    The low temperature program at Yale was initiated by C. T. Lane (1904-1991) in the fall of 1937 when he was appointed to the teaching staff as an instructor in the department of Physics. Following his doctorate from McGill in 1929 he investigated the magnetic susceptibilities of ``soft'' metals supported by the National Research Council of Canada, the Commissioners of the 1851 Exhibition and a Sterling Fellowship at Yale. Arranged by Louis McKeehan, with 5000 from the new George Sheffield research fund, he started the construction of a Kapitza type helium liquefier. The machine was largely completed in the fall of 1939, yet liquid helium was not made until early December 1940 due to the need for extensive on line purification of the gas. Returning in 1945 from war research, Lane and Henry A. Fairbank (Ph.D 1944) continued the metals work along with new thrusts into Second Sound , properties of helium^ three impurities in liquid helium and starting in the 50's on rotating He II. In 1933 both Lane and Onsager were awarded Sterling Fellowships, which initiated a stimulating experimental- theoretical exchange continuing until they both retired. The best-known example was the rediscovery at Yale of the deHaas-van Alphen effect, previously observed only in bismuth, in zinc; where upon Onsager and his students provided new insights into our understanding of the Fermi surface of metals. With the development of new instrumentation one observed vast changes in experimental style during this period. The evolution of the production of liquid helium from Lane's device though the Collins machine to the commodity business of today now makes experiments of huge size and importance possible.

  15. SuhB Associates with Nus Factors To Facilitate 30S Ribosome Biogenesis in Escherichia coli

    PubMed Central

    Singh, Navjot; Bubunenko, Mikhail; Smith, Carol; Abbott, David M.; Stringer, Anne M.; Shi, Ronald; Court, Donald L.

    2016-01-01

    ABSTRACT A complex of highly conserved proteins consisting of NusB, NusE, NusA, and NusG is required for robust expression of rRNA in Escherichia coli. This complex is proposed to prevent Rho-dependent transcription termination by a process known as “antitermination.” The mechanism of this antitermination in rRNA is poorly understood but requires association of NusB and NusE with a specific RNA sequence in rRNA known as BoxA. Here, we identify a novel member of the rRNA antitermination machinery: the inositol monophosphatase SuhB. We show that SuhB associates with elongating RNA polymerase (RNAP) at rRNA in a NusB-dependent manner. Although we show that SuhB is required for BoxA-mediated antitermination in a reporter system, our data indicate that the major function of the NusB/E/A/G/SuhB complex is not to prevent Rho-dependent termination of rRNA but rather to promote correct rRNA maturation. This occurs through formation of a SuhB-mediated loop between NusB/E/BoxA and RNAP/NusA/G. Thus, we have reassigned the function of these proteins at rRNA and identified another key player in this complex. PMID:26980831

  16. Analysis of r-protein and RNA conformation of 30S subunit intermediates in bacteria

    PubMed Central

    Napper, Nathan; Culver, Gloria M.

    2015-01-01

    The ribosome is a large macromolecular complex that must be assembled efficiently and accurately for the viability of all organisms. In bacteria, this process must be robust and tunable to support life in diverse conditions from the ice of arctic glaciers to thermal hot springs. Assembly of the Small ribosomal SUbunit (SSU) of Escherichia coli has been extensively studied and is highly temperature-dependent. However, a lack of data on SSU assembly for other bacteria is problematic given the importance of the ribosome in bacterial physiology. To broaden the understanding of how optimal growth temperature may affect SSU assembly, in vitro SSU assembly of two thermophilic bacteria, Geobacillus kaustophilus and Thermus thermophilus, was compared with that of E. coli. Using these phylogenetically, morphologically, and environmentally diverse bacteria, we show that SSU assembly is highly temperature-dependent and efficient SSU assembly occurs at different temperatures for each organism. Surprisingly, the assembly landscape is characterized by at least two distinct intermediate populations in the organisms tested. This novel, second intermediate, is formed in the presence of the full complement of r-proteins, unlike the previously observed RI* particle formed in the absence of late-binding r-proteins in E. coli. This work reveals multiple distinct intermediate populations are present during SSU assembly in vitro for several bacteria, yielding insights into RNP formation and possible antimicrobial development toward this common SSU target. PMID:25999315

  17. Nucleotide and deduced amino acid sequences of the lacR, lacABCD, and lacFE genes encoding the repressor, tagatose 6-phosphate gene cluster, and sugar-specific phosphotransferase system components of the lactose operon of Streptococcus mutans.

    PubMed Central

    Rosey, E L; Stewart, G C

    1992-01-01

    The complete nucleotide sequences of lacRABCDF and partial nucleotide sequence of lacE from the lactose operon of Streptococcus mutans are presented. Comparison of the streptococcal lac determinants with those of Staphylococcus aureus and Lactococcus lactis indicate exceptional protein and nucleotide identity. The deduced polypeptides also demonstrate significant, but lower, sequence similarity with the corresponding lactose proteins of Lactobacillus casei. Additionally, LacR has sequence homology with the repressor (DeoR) of the Escherichia coli deoxyribonucleotide operon, while LacC is similar to phosphokinases (FruK and PfkB) from E. coli. The primary translation products of the lacRABCDFE genes are polypeptides of 251 (M(r) 28,713), 142 (M(r) 15,610), 171 (M(r) 18,950), 310 (M(r) 33,368), 325 (M(r) 36,495), 104 (M(r) 11,401), and 123 (NH2-terminal) amino acids, respectively. As inferred from their direct homology to the staphylococcal lac genes, these determinants would encode the repressor of the streptococcal lactose operon (LacR), galactose-6-phosphate isomerase (LacA and LacB), tagatose-6-phosphate kinase (LacC), tagatose-1,6-bisphosphate aldolase (LacD), and the sugar-specific components enzyme III-lactose (LacF) and enzyme II-lactose (LacE) of the S. mutans phosphoenolpyruvate-dependent phosphotransferase system. The nucleotide sequence encompassing the S. mutans lac promoter appears to contain repeat elements analogous to those of S. aureus, suggesting that repression and catabolite repression of the lactose operons may be similar in these organisms. Images PMID:1400164

  18. Measurement of proton capture cross sections relevant to rp process with Coulomb dissociation

    SciTech Connect

    Togano, Y.

    2010-08-12

    We have studied proton capture reactions on unstable proton-rich nuclei relevant to rapid proton-capture (rp) process using a Coulomb dissociation method. Using this method, three stellar reactions, {sup 22}Mg(p, {gamma}){sup 23}Al, {sup 26}Si(p, {gamma}){sup 27}P, and {sup 30}S(p, {gamma}){sup 31}Cl were studied at RIKEN Nishina Center. The radiative widths of the first excited state in {sup 23}Al and {sup 27}P, which are relevant to the stellar reactions, were obtained. We discuss the details of the Coulomb dissociation the astrophysical implications obtained from our studies.

  19. Deformation of the Paleozoic metamorphic basement in Tanumé-Pichilemu (34°30' S), Central Chile

    NASA Astrophysics Data System (ADS)

    Palape, C.; Herve, F.; Heredia, N.; Martín-González, F.

    2014-12-01

    We present a new geodynamic evolution for the late Paleozoic accretionary complex of the Chilean coast, located between Tanumé-Pichilemu villages. The accretionary complex has been interpreted as paired metamorphic belt, with continuous exposures along the Coastal Cordillera between 34° and 38°S, was formed during subduction of the paleo-Pacific plate against the southwestern margin of Gondwana. This complex consists of two tectonometamorphic units: (i) a basally accreted HP/LT, the Western Series, formed by metabasites, metacherts, greenschists, blue-schists and marbles, with peak P-T conditions of 7-11 kbar and 350-400°C, that are superimposed on (ii) the frontally accreted Eastern Series, mainly formed by metaturbidites and deformed in HT/LP metamorphic conditions, coeval with the emplacement of the Pennsylvanian Coast Range batholith. The structures observed in the Tanumé-Pichilemu transect has been affected by three deformation episodes related with Gondwanan orogeny (D1, D2, D3), developed in late Carboniferous-Early Permian times. In the Eastern Series, D1 is associated to recumbent isoclinals folds with NW trend and associated (S1) cleavage. The D2 event is related to SW vergent folds which are part of an antiform-synform pair, developing an axial plane cleavage (S2) that dips 30° to the NE. This regional tectonic foliation S2 has intertectonic garnets porphyroblasts. In the Western Series, the first episode (D1) is represented by a foliation (S1) formed under HP-LT metamorphic conditions and preserved in syn-D2 garnet and albite porphyroblast. A NE directed reverse ductile fault system (D2), developed under pressure decreasing conditions, overlaps the HP-LT Western Series, formed about 15-25 km depth, above the shallow HT/LP Eastern Series. In this context the D2 of the Eastern Series are formed previously to D2 episode of the Western Series. The third deformative event D3 is linked to west-verging kilometric-scale antiform, related to a fragile reverse fault that thrust the Eastern Series above the Western Series. This episode is associated with a S3 cleavage. The D3 reverse fault presents a minor sinestral movement, probably related to the Andean orogenic cycle. This work has been supported by FONDECYT grant 1130227, and TORANDES (CGL2012-38396-C03) Spanish I+D+i Plan.

  20. Lower plate deformation at the Chile Triple Junction from the paleomagnetic record (45°30'S-46°S)

    NASA Astrophysics Data System (ADS)

    Lagabrielle, Yves; Bourgois, Jacques; Dyment, Jerôme; Pelletier, Bernard

    2015-08-01

    During the Chile Triple Junction (CTJ) cruise, geophysical surveys were conducted between 45°S and 48°S, in the region of the Chile Triple Junction (CTJ), where the Nazca and Antarctica Plates are subducting beneath the South American Plate. Near the CTJ, the South Chile Rise (SCR), which separates the Nazca and Antarctica lower plates, consists of three spreading segments trending ~N160°, separated by a series of parallel fracture zones. The active spreading centers of the three segments consist of grabens with various widths and depths, bounded by steep fault scarps. We provide robust data showing that the SCR recorded remote and long-term effects of ridge subduction far from the subduction front. Magnetic profiles, multibeam bathymetric, and seismic data were acquired at intervals of 13 km along a N80°E direction across the SCR during the CTJ cruise of R/V L'Atalante. Deformation of the oceanic lithosphere includes (1) a segmentation of the spreading axes along strike, (2) some ridge jumps, and (3) local constriction and changes in trend of the fracture zone valleys. Off-axis volcanism is observed in places that may suggest a link with an abnormal stress field induced by ridge subduction. The tectonic and volcanic anomalies, which occurred in response to the subduction of the SCR1 axis, may be correlated with geochemical anomalies and slab fragmentation recognized by previous works.

  1. Pu236(n,f) , Pu237(n,f) , and Pu238(n,f) cross sections deduced from (p,t) , (p,d) , and (p,p') surrogate reactions

    SciTech Connect

    Hughes, R. O.; Beausang, C. W.; Ross, T. J.; Burke, J. T.; Casperson, R. J.; Cooper, N.; Escher, J. E.; Gell, K.; Good, E.; Humby, P.; McCleskey, M.; Saastimoinen, A.; Tarlow, T. D.; Thompson, I. J.

    2014-07-01

    The Pu236(n,f), Pu237(n,f) and Pu238(n,f) cross sections have been inferred by utilizing the surrogate ratio method. Targets of Pu239 and U235 were bombarded with 28.5-MeV protons, and the light ion recoils, as well as fission fragments, were detected using the STARS detector array at the K150 Cyclotron at the Texas A&M cyclotron facility. The (p, tf) reaction on Pu239 and U235 targets was used to deduce the σ (Pu236(n,f))/σ(U232(n,f)) ratio, and the Pu236(n,f) cross section was subsequently determined for En=0.5–7.5 MeV. Similarly, the (p,df) reaction on the same two targets was used to deduce the σ(Pu237(n,f))/σ(U233(n,f)) ratio, and the Pu237(n,f) cross section was extracted in the energy range En=0.5–7 MeV. The Pu238(n,f) cross section was also deduced by utilizing the (p,p') reaction channel on the same targets. There is good agreement with the recent ENDF/B-VII.1 evaluated cross section data for Pu238(n,f) in the range En=0.5–10.5 MeV and for Pu237(n,f) in the range En=0.5–7 MeV; however, the Pu236(n,f) cross section deduced in the present work is higher than the evaluation between 2 and 7 MeV.

  2. Properties of nearby interstellar hydrogen deduced from Lyman-alpha sky background measurements

    NASA Technical Reports Server (NTRS)

    Thomas, G. E.

    1972-01-01

    For a sufficiently rapid relative motion of the solar system and the nearby interstellar gas, neutral atoms may be expected to penetrate the heliosphere before becoming ionized. Recent satellite measurements of the Lyman alpha emission above the geocorona indicate such an interstellar wind of neutral hydrogen emerging from the direction of Sagittarius and reaching to within a few astronomical units of the sun. A detailed model of the scattering of solar Lyman alpha from the spatial distribution of neutral hydrogen in interplanetary space is presented. This asymmetric distribution is established by solar wind and solar ultraviolet ionization processes along the trajectories of the incoming hydrogen atoms. The values of the interstellar density, the relative velocity, and the gas temperature are adjusted to agree with the Lyman alpha measurements. The results may be interpreted in terms of two models, the cold model and the hot model of the interstellar gas, depending on whether galactic Lyman alpha emission is present at its maximum allowable value or negligibly small.

  3. Fungal diversity from various marine habitats deduced through culture-independent studies.

    PubMed

    Manohar, Cathrine Sumathi; Raghukumar, Chandralata

    2013-04-01

    Studies on the molecular diversity of the micro-eukaryotic community have shown that fungi occupy a central position in a large number of marine habitats. Environmental surveys using molecular tools have shown the presence of fungi from a large number of marine habitats such as deep-sea habitats, pelagic waters, coastal regions, hydrothermal vent ecosystem, anoxic habitats, and ice-cold regions. This is of interest to a variety of research disciplines like ecology, evolution, biogeochemistry, and biotechnology. In this review, we have summarized how molecular tools have helped to broaden our understanding of the fungal diversity in various marine habitats. Majority of the environmental phylotypes could be grouped as novel clades within Ascomycota, Basidiomycota, and Chytridiomycota or as basal fungal lineages. Deep-branching novel environmental clusters could be grouped within Ascomycota as the Pezizomycotina clone group, deep-sea fungal group-I, and soil clone group-I, within Basidiomycota as the hydrothermal and/or anaerobic fungal group, and within Chytridiomycota as Cryptomycota or the Rozella clade. However, a basal true marine environmental cluster is still to be identified as most of the clusters include representatives from terrestrial regions. The challenge for future research is to explore the true marine fungi using molecular techniques. PMID:23363246

  4. Rapid N-S extension in the Mygdonian Graben (northern Greece) deduced from repeated geodetic surveys

    NASA Astrophysics Data System (ADS)

    Martinod, Joseph; Hatzfeld, Denis; Savvaidis, Paris; Katsambalos, Kostas

    In November 1994, a geodetic network situated on the Mygdonian graben, 30 km NE of Thessaloniki, Greece, was remeasured using the GPS technique. This network was established in 1979, in the epicentral area of the 1978 earthquake (Ms=6.5), and was measured using triangulation techniques seven times between 1979 and 1989. The comparison between 1979 and 1994 data shows that this part of the Mygdonian graben experienced about 8 cm of N-S horizontal extension. Most of the extension is concentrated in a narrow (one or two kilometers) E-W zone, located on the southern boundary of the graben. Furthermore, the analysis of repeated triangulation surveys suggests a rate of extension of 5.7±1.3 mm/y, that remained constant with time between 1979 and 1994. This extension could result from long-term postseismic relaxation processes, or from continous aseismic slip within the graben.

  5. The Energy of Olivine Grain Boundaries Deduced from Grain Boundary Frequency Analyses

    NASA Astrophysics Data System (ADS)

    Marquardt, K.; Rohrer, G. S.

    2015-12-01

    The properties of grain boundaries strongly differ from those of the crystal lattice, and there is growing evidence that the presence of grain boundaries influence detected geophysical signals such as electrical conductivity and seismic velocities especially in aggregates with a LPO that favours the alignment of specific grain boundaries. However, neither the anisotropic frequency or energy distribution of grain boundary networks are understood in olivine dominated aggregates, neither with nor without LPO. We used electron backscatter diffraction, EBSD to detect the orientations of over 1.4x104 grains corresponding to roughly 5000mm length of grain boundary separating them. Subsequently we used a stereological approach to determine the grain boundary character distribution, GBCD, defined as the relative areas of grain boundaries of different types, distinguished by their five degrees of freedom (Rohrer, 2007). The grain boundary planes showed a preference for low index planes, which is in agreement with recent findings on other materials (e.g. MgO, TiO2, SrTiO3, MgAl2O4). However, our inferred surface energies are controversial with respect to previously simulated surface energies (Watson et al., 1997; de Leeuw et al., 2000; Gurmani et al., 2011). We find that the principal crystallographic planes have the lowest energies and that at 60° misorientation specific grain boundaries with common [100] axis of misorientation are favored compared to 60° misorientations about random axis of rotation. This seems to support the results of (Faul and Fitz Gerald, 1999), even though our data imply that 90°/[001] (100)(010) should be even less favorable for the propagation of melt films. These differences and similarities will be discussed with respect to the different methods and their limitations. References: Faul U. H. and Fitz Gerald J. D. (1999) Phys. Chem. Miner. 26, 187-197. Gurmani S. F. et al. (2011). J. Geophys. Res. 116, B12209. De Leeuw N. H. et al. (2000) Phys. Chem. Miner. 27, 332-341. Rohrer G. S. et al. (2004) Z. Metallkd. 95, 1-18. Watson G. W., Oliver P. M. and Parker S. C. (1997) Phys. Chem. Miner. 25, 70-78.

  6. Characterization of defensin gene from abalone Haliotis discus hannai and its deduced protein

    NASA Astrophysics Data System (ADS)

    Hong, Xuguang; Sun, Xiuqin; Zheng, Minggang; Qu, Lingyun; Zan, Jindong; Zhang, Jinxing

    2008-11-01

    Defensin is one of preserved ancient host defensive materials formed in biological evolution. As a regulator and effector molecule, it is very important in animals’ acquired immune system. This paper reports the defensin gene from the mixed liver and kidney cDNA library of abalone Haliotis discus hannai Ino. Sequence analysis shows that the gene sequence of full-length cDNA encodes 42 mature peptides (including six Cys), molecular weight of 4 323 Da, and pI of 8.02. Amino acid sequence homology analysis shows that the peptides are highly similar (70% in common) to other insects defensin. Because of a typical insect-defensin structural character of mature peptide in the secondary structure, the polypeptide named Haliotis discus defensin (hd-def), a novel of antimicrobial peptides, belongs to insects defensin subfamily. The RT-PCR result of Haliotis discus defensin shows that the gene can be expressed only in the hepatopancreas by Gram-negative and positive bacteria stimulation, which is ascribed to inducible expression. Therefore, it is revealed that the Haliotis discus defensin gene expression was related to the antibacterial infection of Haliotis discus hannai Ino.

  7. Mean age of rifting and volcanism on Venus deduced from impact crater densities

    NASA Astrophysics Data System (ADS)

    Price, Maribeth; Suppe, John

    1994-12-01

    UNLIKE the extensively cratered highlands of the Moon and Mars, the surface of Venus does not preserve a record of heavy bombard-ment from the early history of the Solar System1-3. Those craters that are found on Venus appear to be statistically indistinguishable from a random spatial population and rarely show modification by folds, faults and lava flows1-3. Although the volcanic and tec-tonic history of Venus is still much debated2-5, there is mounting evidence for near-global resurfacing ˜300-500 Myr ago1,2,6. Moreover, it has recently been noted that the density of impact craters on large volcanic structures is less than the average crater density of the planet, suggestive of significant activity after the resurfacing event7. It is not clear, however, whether these features represent late remnants of the global event or continuing volcanism and tectonism of a still active planet. To address this question, we have used the regional variations in crater density to date volcan-oes, rifts and coronae which, based on stratigraphic evidence, clearly post-date the main resurfacing event8-11. The calculated mean ages of 70-125 Myr exclude the possibility that the majority of these features represent the final stages of the global event.

  8. Neptune’s global circulation deduced from multi-wavelength observations

    NASA Astrophysics Data System (ADS)

    de Pater, Imke; Fletcher, Leigh N.; Luszcz-Cook, Statia; DeBoer, David; Butler, Bryan; Hammel, Heidi B.; Sitko, Michael L.; Orton, Glenn; Marcus, Philip S.

    2014-07-01

    We observed Neptune between June and October 2003 at near- and mid-infrared wavelengths with the 10-m W.M. Keck II and I telescopes, respectively; and at radio wavelengths with the Very Large Array. Images were obtained at near-infrared wavelengths with NIRC2 coupled to the adaptive optics system in both broad- and narrow-band filters between 1.2 and 2.2 μm. In the mid-infrared we imaged Neptune at wavelengths between 8 and 22 μm, and obtained slit-resolved spectra at 8-13 μm and 18-22 μm. At radio wavelengths we mapped the planet in discrete filters between 0.7 and 6 cm. We analyzed each dataset separately with a radiative-transfer program that is optimized for that particular wavelength regime. At southern midlatitudes the atmosphere appears to be cooler at mid-infrared wavelengths than anywhere else on the planet. We interpret this to be caused by adiabatic cooling due to air rising at midlatitudes at all longitudes from the upper troposphere up to ≲0.1 mbar levels. At near-infrared wavelengths we find two distinct cloud layers at these latitudes: a relatively deep layer of clouds (presumably methane) in the troposphere at pressure levels P∼300-≳600 mbar, which we suggest to be caused by the large-scale upwelling and its accompanying adiabatic cooling and condensation of methane; and a higher, spatially intermittent, layer of clouds in the stratosphere at 20-30 mbar. The latitudes of these high clouds encompass an anticyclonic band of zonal flow, which suggests that they may be due to strong, but localized, vertical upwellings associated with local anticyclones, rather than plumes in convective (i.e., cyclonic) storms. Clouds at northern midlatitudes are located at the highest altitudes in the atmosphere, near 10 mbar. Neptune’s south pole is considerably enhanced in brightness at both mid-infrared and radio wavelengths, i.e., from ∼0.1 mbar levels in the stratosphere down to tens of bars in the troposphere. We interpret this to be due to subsiding motions from the stratosphere all the way down to the deep troposphere. The enhanced brightness observed at mid-infrared wavelengths is interpreted to be due to adiabatic heating by compression in the stratosphere, and the enhanced brightness temperature at radio wavelengths reveals that the subsiding air over the pole is very dry; the relative humidity of H2S over the pole is only 5% at altitudes above the NH4SH cloud at ∼40 bar. The low humidity region extends from the south pole down to latitudes of 66°S. This is near the same latitudes as the south polar prograde jet signifying the boundary of the polar vortex. We suggest that the South Polar Features (SPFs) at latitudes of 60-70° are convective storms, produced by baroclinic instabilities expected to be produced at latitudes near the south polar prograde jet. Taken together, our data suggest a global circulation pattern where air is rising above southern and northern midlatitudes, from the troposphere up well into the stratosphere, and subsidence of dry air over the pole and equator from the stratosphere down into the troposphere. We suggest that this pattern extends all the way from ≲0.1 mbar down to pressures of ≳40 bar.

  9. Origin and evolution of organisms as deduced from 5S ribosomal RNA sequences.

    PubMed

    Hori, H; Osawa, S

    1987-09-01

    A phylogenetic tree of most of the major groups of organisms has been constructed from the 352 5S ribosomal RNA sequences now available. The tree suggests that there are several major groups of eubacteria that diverged during the early stages of their evolution. Metabacteria (= archaebacteria) and eukaryotes separated after the emergence of eubacteria. Among eukaryotes, red algae emerged first; and, later, thraustochytrids (a Proctista group), ascomycetes (yeast), green plants (green algae and land plants), "yellow algae" (brown algae, diatoms, and chrysophyte algae), basidiomycetes (mushrooms and rusts), slime- and water molds, various protozoans, and animals emerged, approximately in that order. Three major types of photosynthetic eukaryotes--i.e., red algae (= Chlorophyll a group), green plants (Chl. a + b group) and yellow algae (Chl. a + c)--are remotely related to one another. Other photosynthetic unicellular protozoans--such as Cyanophora (Chl. a), Euglenophyta (Chl. a + b), Cryptophyta (Chl. a + c), and Dinophyta (Chl. a + c)--seem to have separated shortly after the emergence of the yellow algae. PMID:2452957

  10. Variability of carbonate diagenesis in equatorial Pacific sediments deduced from radiogenic and stable Sr isotopes

    NASA Astrophysics Data System (ADS)

    Voigt, Janett; Hathorne, Ed C.; Frank, Martin; Vollstaedt, Hauke; Eisenhauer, Anton

    2015-01-01

    The recrystallisation (dissolution-precipitation) of carbonate sediments has been successfully modelled to explain profiles of pore water Sr concentration and radiogenic Sr isotope composition at different locations of the global ocean. However, there have been few systematic studies trying to better understand the relative importance of factors influencing the variability of carbonate recrystallisation. Here we present results from a multi-component study of recrystallisation in sediments from the Integrated Ocean Drilling Program (IODP) Expedition 320/321 Pacific Equatorial Age Transect (PEAT), where sediments of similar initial composition have been subjected to different diagenetic histories. The PEAT sites investigated exhibit variable pore water Sr concentrations gradients with the largest gradients in the youngest sites. Radiogenic Sr isotopes suggest recrystallisation was relative rapid, consistent with modelling of other sediment columns, as the 87Sr/86Sr ratios are indistinguishable (within 2σ uncertainties) from contemporaneous seawater 87Sr/86Sr ratios. Bulk carbonate leachates and associated pore waters of Site U1336 have lower 87Sr/86Sr ratios than contemporaneous seawater in sediments older than 20.2 Ma most likely resulting from the upward diffusion of Sr from older recrystallised carbonates. It seems that recrystallisation at Site U1336 may still be on-going at depths below 102.5 rmcd (revised metres composite depth) suggesting a late phase of recrystallisation. Furthermore, the lower Sr/Ca ratios of bulk carbonates of Site U1336 compared to the other PEAT sites suggest more extensive diagenetic alteration as less Sr is incorporated into secondary calcite. Compared to the other PEAT sites, U1336 has an inferred greater thermal gradient and a higher carbonate content. The enhanced thermal gradient seems to have made these sediments more reactive and enhanced recrystallisation. In this study we investigate stable Sr isotopes from carbonate-rich deep sea sediments for the first time. Pore water δ88/86Sr increases with depth (from 0.428‰ to values reaching up to 0.700‰) at Site U1336 documenting an isotope fractionation process during recrystallisation. Secondary calcite preferentially incorporates the lighter Sr isotope (86Sr) leaving pore waters isotopically heavy. The δ88/86Sr values of the carbonates themselves show more uniform values with no detectable change with depth. Carbonates have a much higher Sr content and total Sr inventory than the pore waters meaning pore waters are much more sensitive to fractionation processes than the carbonates. The δ88/86Sr results indicate that pore water stable Sr isotopes have the potential to indicate the recrystallisation of carbonate sediments.

  11. Active Structure Evolutions Deduced from Geomorphic and Geodetic Evidence, from Hsinchu to Taoyuan, Northwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Wang, Y.; Hou, C.; Chen, W.

    2003-12-01

    As we know, Taiwan fault-and-thrust belt is built up by the arc-continent collision that is related to polarity flipping of subduction. The flipping boundary, delineated from Hsinchu to Hualien, divides the mountain belt into northern as well as southern part. Looking at the current tectonic configuration surrounding Taiwan, the northern one corresponds to the Ryukyu arc-trench system and has recently been influenced by back-arc rifting of Okinawa Trough (OT), which reactivated during Quaternary. As a consequence, the stress currently executing in northern Taiwan must be different from the southern Taiwan, manifesting to different neotectonic features. It is governed by the extensional stress transferred from OT. Basins, such as Taipei and Ilan, are the evidence to confirm this point. Along the western Taiwan located to the south of Taipei basin is the Taoyuan-Hsinchu area, where the landscape is still characterized by those previously produced under compression. In Taoyuan, two subparallel blind fault-related folds with axes trending NNE were developed due to the reactivation of preexisting normal fault system in continental margin. The entire system remained active until later than 30 ka. To the Hsinchu, the neotectonics is characterized by another two duplex systems (each one is composed of a thrust and its related anticline). The structural orientation is similar to of the Taoyuan. There are two main drainages, i,e.,Touchien and Fengshan rivers, flow across and separate Taoyuan and Hsinchu. Evident linear scarps and lineations have been developed aside oblique to the above-mentioned orientations of compression structures but roughly following the flowing direction. We interpret that they are generated by wrench fault systems tearing apart the original structures to accommodate the recently adjusted stress field. As recognized by the relevant geomorphic evidence, they are suggested as strike-slip faults with possibly normal dip-slip component. The newly accomplished dataset derived from geodetic network shows that except for the Hsincheng fault nearly no detectable contraction occurs across the major structures in the study area. The most surprising phenomenon is that the Fengshan river geodetically plays a major boundary. The northern crust (Taoyuan) is moving due east relatively to the southern crust (Hsinchu) in a rate of ca. 2 cm/yr. This represents that the Fengshan river is currently a right-lateral strike-slip fault, confirming the former strike-slip suggested by geomorphic features. To probe the other details, more stations and precise measurements are needed in the future.

  12. High-frequency Earth rotation variations deduced from altimetry-based ocean tides

    NASA Astrophysics Data System (ADS)

    Madzak, Matthias; Schindelegger, Michael; Böhm, Johannes; Bosch, Wolfgang; Hagedoorn, Jan

    2016-06-01

    A model of diurnal and semi-diurnal variations in Earth rotation parameters (ERP) is constructed based on altimetry-measured tidal heights from a multi-mission empirical ocean tide solution. Barotropic currents contributing to relative angular momentum changes are estimated for nine major tides in a global inversion algorithm that solves the two-dimensional momentum equations on a regular 0.5° grid with a heavily weighted continuity constraint. The influence of 19 minor tides is accounted for by linear admittance interpolation of ocean tidal angular momentum, although the assumption of smooth admittance variations with frequency appears to be a doubtful concept for semi-diurnal mass terms in particular. A validation of the newly derived model based on post-fit corrections to polar motion and universal time (Δ UT1) from the analysis of Very Long Baseline Interferometry (VLBI) observations shows a variance reduction for semi-diurnal Δ UT1 residuals that is significant at the 0.05 level with respect to the conventional ERP model. Improvements are also evident for the explicitly modeled K_1 , Q_1 , and K_2 tides in individual ERP components, but large residuals of more than 15 μ as remain at the principal lunar frequencies of O_1 and M_2 . We attribute these shortcomings to uncertainties in the inverted relative angular momentum changes and, to a minor extent, to violation of mass conservation in the empirical ocean tide solution. Further dedicated hydrodynamic modeling efforts of these anomalous constituents are required to meet the accuracy standards of modern space geodesy.

  13. Hydrology of the Greater Tongonan geothermal system, Philippines, as deduced from geochemical and isotopic data

    SciTech Connect

    Alvis-Isidro, R.R.; Solana, R.R.; D`amore, F.; Nuti, S.; Gonfiantini, R.

    1993-10-01

    Fluids in the Greater Tongonan geothermal system exhibit a large positive {sup 18}O shift from the Leyte meteoric water line. However, there is also a significant shift in {sup 2}H. The {delta}{sup 2}H-{delta}{sup 18}O plot shows that the geothermal fluids may be derived by the mixing of meteoric water with local magmatic water. The most enriched water in the Greater Tongonan system, in terms of {delta}{sup 18}O, {delta}{sup 2}H and Cl, is comprised of approximately 40% magmatic water. Baseline isotope results support a hydrogeochemical model in which there is increasing meteoric water dilution to the southeast, from Mahiao to Sambaloran and towards Malitbog. The Cl-{delta}{sup 18}O plot confirms that the geothermal fluid in Mahanagdong, further southeast, is distinct from that of the Mahiao-Sambaloran-Malitbog system.

  14. Postglacial species displacement in Triturus newts deduced from asymmetrically introgressed mitochondrial DNA and ecological niche models

    PubMed Central

    2012-01-01

    Background If the geographical displacement of one species by another is accompanied by hybridization, mitochondrial DNA can introgress asymmetrically, from the outcompeted species into the invading species, over a large area. We explore this phenomenon using the two parapatric crested newt species, Triturus macedonicus and T. karelinii, distributed on the Balkan Peninsula in south-eastern Europe, as a model. Results We first delimit a ca. 54,000 km2 area in which T. macedonicus contains T. karelinii mitochondrial DNA. This introgression zone bisects the range of T. karelinii, cutting off a T. karelinii enclave. The high similarity of introgressed mitochondrial DNA haplotypes with those found in T. karelinii suggests a recent transfer across the species boundary. We then use ecological niche modeling to explore habitat suitability of the location of the present day introgression zone under current, mid-Holocene and Last Glacial Maximum conditions. This area was inhospitable during the Last Glacial Maximum for both species, but would have been habitable at the mid-Holocene. Since the mid-Holocene, habitat suitability generally increased for T. macedonicus, whereas it decreased for T. karelinii. Conclusion The presence of a T. karelinii enclave suggests that T. karelinii was the first to colonize the area where the present day introgression zone is positioned after the Last Glacial Maximum. Subsequently, we propose T. karelinii was outcompeted by T. macedonicus, which captured T. karelinii mitochondrial DNA via introgressive hybridization in the process. Ecological niche modeling suggests that this replacement was likely facilitated by a shift in climate since the mid-Holocene. We suggest that the northwestern part of the current introgression zone was probably never inhabited by T. karelinii itself, and that T. karelinii mitochondrial DNA spread there through T. macedonicus exclusively. Considering the spatial distribution of the introgressed mitochondrial DNA and the signal derived from ecological niche modeling, we do not favor the hypothesis that foreign mitochondrial DNA was pulled into the T. macedonicus range by natural selection. PMID:22935041

  15. Deducing Wild 2 Components with a Statistical Dataset of Olivine in Chondrite Matrix

    NASA Technical Reports Server (NTRS)

    Frank, D. R.; Zolensky, M. E.; Le, L.

    2012-01-01

    Introduction: A preliminary exam of the Wild 2 olivine yielded a major element distribution that is strikingly similar to those for aqueously altered carbonaceous chondrites (CI, CM, and CR) [1], in which FeO-rich olivine is preferentially altered. With evidence lacking for large-scale alteration in Wild 2, the mechanism for this apparent selectivity is poorly understood. We use a statistical approach to explain this distribution in terms of relative contributions from different chondrite forming regions. Samples and Analyses: We have made a particular effort to obtain the best possible analyses of both major and minor elements in Wild 2 olivine and the 5-30 micrometer population in chondrite matrix. Previous studies of chondrite matrix either include larger isolated grains (not found in the Wild 2 collection) or lack minor element abundances. To overcome this gap in the existing data, we have now compiled greater than 10(exp 3) EPMA analyses of matrix olivine in CI, CM, CR, CH, Kakangari, C2-ungrouped, and the least equilibrated CO, CV, LL, and EH chondrites. Also, we are acquiring TEM/EDXS analyses of the Wild 2 olivine with 500s count times, to reduce relative errors of minor elements with respect to those otherwise available. Results: Using our Wild 2 analyses and those from [2], the revised major element distribution is more similar to anhydrous IDPs than previous results, which were based on more limited statistics (see figure below). However, a large frequency peak at Fa(sub 0-1) still persists. All but one of these grains has no detectable Cr, which is dissimilar to the Fa(sub 0-1) found in the CI and CM matrices. In fact, Fa(sub 0-1) with strongly depleted Cr content is a composition that appears to be unique to Kakangari and enstatite (highly reduced) chondrites. We also note the paucity of Fa(sub greater than 58), which would typically indicate crystallization in a more oxidizing environment [3]. We conclude that, relative to the bulk of anhydrous IDPs, Wild 2 may have received a larger contribution from the Kakangari and/or enstatite chondrite forming regions. Alternatively, Wild 2 may have undergone accretion in an anomalously reducing region, marked by nebular condensation of this atypical forsterite. In [4], a similar conclusion was reached with an Fe-XANES study. We will also use similar lines of reasoning, and our previous conclusions in [5], to constrain the relative contributions of silicates that appear to have been radially transported from different ordinary and carbonaceous chondrite forming regions to the Kuiper Belt. In addition, the widespread depletion of Cr in these FeO-rich (Fa(sub greater than 20)) fragments is consistent with mild thermal metamorphism in Wild 2.

  16. Irradiation History of Itokawa Regolith Material Deduced from Noble Gases in the Hayabusa Samples

    NASA Astrophysics Data System (ADS)

    Nagao, Keisuke; Okazaki, Ryuji; Nakamura, Tomoki; Miura, Yayoi N.; Osawa, Takahito; Bajo, Ken-ichi; Matsuda, Shintaro; Ebihara, Mitsuru; Ireland, Trevor R.; Kitajima, Fumio; Naraoka, Hiroshi; Noguchi, Takaaki; Tsuchiyama, Akira; Yurimoto, Hisayoshi; Zolensky, Michael E.; Uesugi, Masayuki; Shirai, Kei; Abe, Masanao; Yada, Toru; Ishibashi, Yukihiro; Fujimura, Akio; Mukai, Toshifumi; Ueno, Munetaka; Okada, Tatsuaki; Yoshikawa, Makoto; Kawaguchi, Junichiro

    2011-08-01

    Noble gas isotopes were measured in three rocky grains from asteroid Itokawa to elucidate a history of irradiation from cosmic rays and solar wind on its surface. Large amounts of solar helium (He), neon (Ne), and argon (Ar) trapped in various depths in the grains were observed, which can be explained by multiple implantations of solar wind particles into the grains, combined with preferential He loss caused by frictional wear of space-weathered rims on the grains. Short residence time of less than 8 million years was implied for the grains by an estimate on cosmic-ray-produced 21Ne. Our results suggest that Itokawa is continuously losing its surface materials into space at a rate of tens of centimeters per million years. The lifetime of Itokawa should be much shorter than the age of our solar system.

  17. Radial profile of the inner heliospheric magnetic field as deduced from Faraday rotation observations

    NASA Astrophysics Data System (ADS)

    Mancuso, S.; Garzelli, M. V.

    2013-05-01

    Faraday rotation measures (RMs) of the polarized emission from extragalactic radio sources occulted by the coronal plasma were used to infer the radial profile of the inner heliospheric magnetic field near the solar minimum. By inverting LASCO/SOHO polarized brightness (pB) data taken during the observations in May 1997, we retrieved the electron density distribution along the lines of sight to the sources, which allowed us to separate the two plasma properties that contribute to the observed RMs. By comparing the observed RM values with those theoretically predicted by a power law model of the radial component of the coronal magnetic field using a best-fitting procedure, we found that the radial component of the inner heliospheric magnetic field can be nicely approximated by a power law of the form Br = 3.76 r-2.29 G in a range of heights from about 5 to 14 R⊙. Finally, our analysis suggests that the radial computation of the potential field source surface model from the Wilcox Solar Observatory is the preferred choice near solar minimum assuming a radial field in the photosphere and a source surface located at Rss = 2.5 R⊙.

  18. Mechanism of carboxypeptidase-Y-catalyzed reaction deduced from a pressure-dependence study.

    PubMed

    Fukuda, M; Kunugi, S

    1985-06-18

    The activation volumes for kcat of the carboxypeptidase-Y-catalyzed hydrolysis of ester substrates were slightly negative (-1 to -4 ml/mol), while those for peptide and depsi-peptide analog were highly positive (+10 to +27 ml/mol). These values and the contrasting pH dependences of these two groups of the substrates are explained by a mechanism involving three ionic states of the enzyme and the second stable intermediate (acyl-enzyme). Esters are mostly rate-controlled by the deacylation step and peptides are controlled by both the acylation and the deacylation steps. Pressure increase induced a partial shift of the rate-determining step. Reaction volumes for Km-1 of peptide and depsi-peptide analog showed large and positive values (+16 to +29 ml/mol) which reflects the electrostatic interaction in the substrate recognition by this enzyme. PMID:4006944

  19. Properties of Turbulent Dynamics and Oscillations of Main-Sequence Stars Deduced From Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Kitiashvili, Irina N.; Mansour, Nagi N.; Kosovichev, Alexander; Wray, Alan A.

    2015-08-01

    Unique observational data from the Kepler mission open new perspectives for detail investigation of dynamical and internal properties of numerous stars. However, the new observational results require better understand links between the stellar turbulent convection and oscillations. We perform 3D numerical radiative hydrodynamics simulations of convective and oscillation properties of main-sequence stars from the solar-type stars to more massive F- and A-type stars. As the stellar mass increases the convection zone shrinks making it possible to include the whole convection zone in the computational domain. Also in more massive stars the scale and intensity of the turbulent motions dramatically increases, providing more energy for excitation of acoustic and gravity modes. In this talk I will discuss properties of the turbulent dynamics of the stars, interaction between the radiative and convection zones, and excitation of acoustic and gravity modes.

  20. The RCS of a microstrip dipole deduced from an expansion of pole singularities

    NASA Astrophysics Data System (ADS)

    Hanson, George W.; Nyquist, Dennis P.

    1993-03-01

    The SEM is applied to the steady-state analysis of plane wave scattering from microstrip dipoles. The current induced on the antenna is expanded in a series of natural modes, where the amplitude of each term in the expansion is expressed as a coupling coefficient weighted by a simple frequency pole. Natural modes occur at pole singularities of the antenna current in the complex frequency plane, and are found by a numerical root search of a homogeneous matrix equation. This formulation results in an accurate and efficient calculation of the radar cross section of microstrip dipoles which exhibit some appreciable resonant characteristics, where it is found that the current resonance dominates the response of the antenna. The SEM applied here yields good physical insight into the scattering behavior of such antennas. Results obtained with the SEM analysis are compared with a full-wave method of moments solution.

  1. Neutrino properties deduced from the study of lepton number violating processes at low and high energies

    SciTech Connect

    Stoica, Sabin

    2012-11-20

    There is nowadays a significant progress in understanding the neutrino properties. The results of the neutrino oscillation experiments have convincingly showed that neutrinos have mass and oscillate, in contradiction with the Standard Model (SM) assumptions, and these are the first evidences of beyond SM physics. However, fundamental properties of the neutrinos like their absolute mass, their character (are they Dirac or Majorana particles?), their mass hierarchy, the number of neutrino flavors, etc., still remain unknown. In this context there is an increased interest in the study of the lepton number violating (LNV) processes, since they could complete our understanding on the neutrino properties. Since recently, the neutrinoless double beta decay was considered the only process able to distinguish between Dirac or Majorana neutrinos and to give a hint on the absolute mass of the electron neutrino. At present, the increased luminosity of the LHC experiments makes feasible the search of LNV processes at high energy as well. In this lecture I will make a brief review on our present knowledge of the neutrino properties, on the present status of the double-beta decay studies and on the first attempts to search LNV processes at LHC.

  2. [Migration and professions: deducing Italian immigration to Argentina from nominative sources].

    PubMed

    Frid De Silberstein, C L

    1996-12-01

    "The article examines the possibilities of systematically exploiting nominative document corpuses related to immigration in Buenos Aires [Argentina] in the period of mass migration [1885-1910], and proposes to focus on the occupations declared by the Italian immigrants. After reviewing the formal aspects of the documental series used (missing information, polysemy of professional aggregates) the immigration of masons is analyzed, taking into account demographic characteristics, annual rhythms of arrival, [and] migration typologies." (EXCERPT) PMID:12348431

  3. Light elements burning reaction rates at stellar temperatures as deduced by the Trojan Horse measurements

    SciTech Connect

    Lamia, L.; Spitaleri, C.; La Cognata, M.; Palmerini, S.; Sergi, M. L.; Puglia, S. M. R.

    2015-02-24

    Experimental nuclear astrophysics aims at determining the reaction rates for astrophysically relevant reactions at their Gamow energies. For charged-particle induced reactions, the access to these energies is usually hindered, in direct measurements, by the presence of the Coulomb barrier between the interacting particles or by electron screening effects, which make hard the determination of the bare-nucleus S(E)-factor of interest for astrophysical codes. The use of the Trojan Horse Method (THM) appears as one of the most suitable tools for investigating nuclear processes of interest for astrophysics. Here, in view of the recent TH measurements, the main destruction channels for deuterium ({sup 2}H), for the two lithium {sup 6,7}Li isotopes, for the {sup 9}Be and the one for the two boron {sup 10,11}B isotopes will be discussed.

  4. Total Vertical Offset for the Beichuan Fault (Longmen Shan, Sichuan, China) Deduced from Metamorphic Minerals

    NASA Astrophysics Data System (ADS)

    Airaghi, L.; de Sigoyer, J.; Vidal, O.; Lanari, P.; Tan, X. B.; Xu, X.; Guillot, S.

    2015-12-01

    The paradox of high topography but low convergence rates in the Longmen Shan mountain belt, at the eastern margin of Tibetan plateau (Sichuan, China) leaded to an underestimation of the seismic hazard prior to the Wenchuan earthquake Mw 7.9 (2008). The rupture affected the crustal Beichuan fault, with both thrusting and dextral slide slip components. This fault is responsible for the exhumation of the basement over Triassic sediments. Several paleoseismological studies have well constrained the Quaternary activity of this fault, and thermochronological data show a rapid exhumation starting from Oligocene. The total offset of the Beichuan fault remains unknown. Samples collected in the hanging wall of the Beichuan fault, yield stable white mica, chlorite, epidote and quartz. Chemical and thermobarometric analyses of metamorphic minerals yield metamorphic peak conditions at 300±50°C and 7-8 kbar. Such P,T conditions suggest burial to 18-20 km depth, and represent the maximum vertical offset of the Beichuan fault. Comparison of results from distant sampled sites along the Beichuan fault reveals the spatial continuity of this offset along the Beichuan fault. The attainment of peak pressure conditions will be dated using in-situ laser ablation 40Ar/39Ar dating of the metamorphic micas. This will help constrain the onset of Beichuan fault activation, which corresponds to the onset of thick skin deformation in the Longmen Shan. [CW1]I deleted all this stuff below because I thought it was too much information for a conference abstract - but you do have space to put it back.

  5. Accretion timescale and impact history of Mars deduced from the isotopic systematics of martian meteorites

    NASA Astrophysics Data System (ADS)

    Borg, Lars E.; Brennecka, Gregory A.; Symes, Steven J. K.

    2016-02-01

    High precision Sm-Nd isotopic analyses have been completed on a suite of 11 martian basaltic meteorites in order to better constrain the age of silicate differentiation on Mars associated with the formation of their mantle sources. These data are used to evaluate the merits and disadvantages of various mathematical approaches that have been employed in previous work on this topic. Ages determined from the Sm-Nd isotopic systematics of individual samples are strongly dependent on the assumed Nd isotopic composition of the bulk planet. This assumption is problematic given differences observed between the Nd isotopic composition of Earth and chondritic meteorites and the fact that these materials are both commonly used to represent bulk planetary Nd isotopic compositions. Ages determined from the slope of 146Sm-142Nd whole rock isochrons are not dependent on the assumed 142Nd/144Nd ratio of the planet, but require the sample suite to be derived from complementary, contemporaneously-formed reservoirs. In this work, we present a mathematical expression that defines the age of formation of the source regions of such a suite of samples that is based solely on the slope of a 143Nd-142Nd whole rock isochron and is also independent of any a priori assumptions regarding the bulk isotopic composition of the planet. This expression is also applicable to mineral isochrons and has been used to successfully calculate 143Nd-142Nd model crystallization ages of early refractory solids as well as lunar samples. This permits ages to be obtained using only Nd isotopic measurements without the need for 147Sm/144Nd isotope dilution determinations. When used in conjunction with high-precision Nd isotopic measurements completed on martian meteorites this expression yields an age of formation of the martian basaltic meteorite source regions of 4504 ± 6 Ma. Because the Sm-Nd model ages for the formation of martian source regions are commonly interpreted to record the age at which large scale mantle reservoirs formed during planetary differentiation associated with magma ocean solidification, the age determined here implies that magma ocean solidification occurred several tens of millions of years after the beginning of the Solar System. Recent thermal models, however, suggest that Mars-sized bodies cool rapidly in less than ∼5 Ma after accretion ceases, even in the presence of a thick atmosphere. Assuming these models are correct, an extended period of accretion is necessary to provide a mechanism to keep portions of the martian mantle partially molten until 4504 Ma. Late accretional heating of Mars could either be associated with protracted accretion occurring at a quasi-steady state or alternatively be associated with a late giant impact. If this scenario is correct, then accretion of Mars-sized bodies takes up to 60 Ma and is likely to be contemporaneous with the core formation and possibly the onset of silicate differentiation. This further challenges the concept that isotopic equilibrium is attained during primordial evolution of planets, and may help to account for geochemical evidence implying addition of material into planetary interiors after core formation was completed.

  6. Properties of CIRRUS Overlapping Clouds as Deduced from the GOES-12 Imagery Data

    NASA Technical Reports Server (NTRS)

    Chang, Fu-Lung; Minnis, Patrick; Lin, Bing; Sun-Mack, Sunny; Khaiyer, Mandana

    2006-01-01

    Understanding the impact of cirrus clouds on modifying both the solar reflected and terrestrial emitted radiations is crucial for climate studies. Unlike most boundary layer stratus and stratocumulus clouds that have a net cooling effect on the climate, high-level thin cirrus clouds can have a warming effect on our climate. Many research efforts have been devoted to retrieving cirrus cloud properties due to their ubiquitous presence. However, using satellite observations to detect and/or retrieve cirrus cloud properties faces two major challenges. First, they are often semitransparent at visible to infrared wavelengths; and secondly, they often occur over a lower cloud system. The overlapping of high-level cirrus and low-level stratus cloud poses a difficulty in determining the individual cloud top altitudes and optical properties, especially when the signals from cirrus clouds are overwhelmed by the signals of stratus clouds. Moreover, the operational satellite retrieval algorithms, which often assume only single layer cloud in the development of cloud retrieval techniques, cannot resolve the cloud overlapping situation properly. The new geostationary satellites, starting with the Twelfth Geostationary Operational Environmental Satellite (GOES-12), are providing a new suite of imager bands that have replaced the conventional 12-micron channel with a 13.3-micron CO2 absorption channel. The replacement of the 13.3-micron channel allows for the application of a CO2-slicing retrieval technique (Chahine et al. 1974; Smith and Platt 1978), which is one of the important passive satellite methods for remote sensing the altitudes of mid to high-level clouds. Using the CO2- slicing technique is more effective in detecting semitransparent cirrus clouds than using the conventional infrared-window method.

  7. Low-latitude ionosphere dynamics as deduced from meridional ionosonde chain: Ionospheric ceiling

    NASA Astrophysics Data System (ADS)

    Maruyama, Takashi; Uemoto, Junpei; Tsugawa, Takuya; Supnithi, Pornchai; Ishii, Mamoru; Komolmis, Tharadol

    Interest in the equatorial anomaly in the ionosphere has been focused mostly on f_oF_2, and not much attention was paid to h_mF_2 except for the time rate of change of it in connection with the vertical plasma drift velocity. There have been few climatological studies on h_mF_2 variations associated with development of the equatorial anomaly. In this paper, we revisit the equatorial anomaly in terms of height variations. For this purpose, we analyzed scaled ionogram parameters from three stations located along the magnetic meridian that is a primary component of Southeast Asia low-latitude ionospheric network (SEALION); one at the magnetic equator and the others at conjugate off-equatorial latitudes near 10 degrees magnetic latitude. The daytime h_mF_2 was investigated for each season during the solar minimum period, 2006-2007 and 2009. The peak height increased for approximately 3 hr after sunrise at all locations, as expected from the daytime upward E×B drift. The apparent upward drift ceased before noon at the magnetic equator, while the layer continued to increase at the off-equatorial latitudes, reaching altitudes higher than the equatorial height around noon. The noon time restricted layer height at the magnetic equator did not depend much on the season, while the maximum peak height at the off-equatorial latitudes largely varied with season. The daytime specific limiting height of the equatorial ionosphere was termed ionospheric ceiling. Numerical modeling using the SAMI2 code reproduced the features of the ionospheric ceiling quite well. Dynamic parameters provided by the SAMI2 modeling were investigated and it was shown that the ionospheric ceiling is another aspect of the fountain effect, in which increased diffusion of plasma at higher altitudes has a leading role.

  8. Thermal regimes in the detachment fault environment as deduced from fluid inclusions

    NASA Astrophysics Data System (ADS)

    Beane, R. E.; Wilkins, J., Jr.; Heidrick, T. L.

    Extensional tectonism, which dominates middle- and late-Tertiary geology in western Arizona, southeastern California, and southern Nevada, is characterized by normal regionally extensive, low-angle detachment faults. The decollement movement of Fupper plate rocks relative to lower plate assemblages created extensive zones of dilatency, including synthetic and antithetic listric normal faults, tear faults, tectonic crush breccias, shatter breccias, and gash veins in lithologic units above and below the detachment. The tectonically enhanced permeability above and below the detachment fault permitted mass migration of large volumes of hydrothermal solutions along the fault zone during and following upper plate movement. Major quantities of MgO, CaO, K2O, FeO/Fe2O3, SiO2 and CO2 were added to rocks in and near the detachment and related structures. Also introduced were varying amounts of trace elements including Mn, Cu, S, Mo, Ba, Au, Pb, Zn, U and/or Ag. Minerals containing fluid incusions were collected from all of these loci at locations in detachment faulted terranes in western Arizona and southeastern California.

  9. Petrographically deduced triassic climate for the Deep River Basin, eastern piedmont of North Carolina

    SciTech Connect

    McCarn, S.T.; Mansfield, C.F.

    1985-01-01

    A petrographic comparison of Triassic, fluvial sandstones from the Deep River Basin in the eastern piedmont of North Carolina with nearby Holocene stream sands (1) indicates that he Triassic climate was more arid than today's and (2) distinguishes an eastern, more plutonic terrane from a western, more metamorphic source terrane. The paleoclimatic interpretation is based on differences in framework composition between modern and ancient sands of the same grain size, derived from the same rock type, transported similar distances and deposited in similar settings. The Triassic sandstones contain more lithic-fragments but less quartz than otherwise equivalent, modern sand in the Deep River Basin. Feldspar content is more complex, controlled by both source-rock composition and climate. Sand from the more plutonic terrane contains more feldspar and plutonic lithic-fragments than sand from the more metamorphic terrane, which contains more quartz and metamorphic lithic-fragments. This petrographic interpretation of the Triassic sandstones along with the presence of coal, limestone, chert and caliche in the middle of the section suggests that the Triassic climate was cyclic, changing from arid to humid and back to arid. Plate-tectonic reconstructions place the Deep River Basin between the Triassic equator and Tropic of cancer, where the easterly trade winds would predominate. Therefore, the arid portions of the cycle could have been due to a periodic, orographic, rain shadow formed as the result of intermittent movement along the Jonesboro Fault, creating a highland area east of the Deep River Basin.

  10. Surface currents in the Caribbean Sea as deduced from Lagrangian observations

    NASA Astrophysics Data System (ADS)

    Molinari, Robert L.; Spillane, Michael; Brooks, Irving; Atwood, Donald; Duckett, Carol

    1981-07-01

    The results of a satellite tracked drifting buoy experiment conducted in the Caribbean Sea from October 1975 through June 1976 are presented. The buoy trajectories suggest that the Aves Rise, Beata Ridge, and Nicaraguan Rise are regions where considerable mesoscale variability occurs in the surface flow. The variability is in the form of current deflections; small diameter eddies ranging in size from 20 to 100 km; large amplitude meanders, with amplitudes greater than 150 km; and large diameter eddies, with diameters greater than 200 km which form on and near these rises and ridges. In the central Caribbean, where the topographic relief is not as dramatic, the flow is predominantly zonal. Intensifications in the surface flow occur off the coast of Colombia, south of the Nicaraguan Rise, and south of the Yucatan Strait.

  11. Declining moisture availability in late Eocene Antarctica as deduced from Nothofagus sporopollenin δ13C

    NASA Astrophysics Data System (ADS)

    Griener, K. W.; Nelson, D. M.; Warny, S.

    2012-12-01

    Palynological data demonstrate that significant changes in vegetation and climate occurred at the Eocene-Oligocene (E-O) Boundary on the Antarctic Peninsula. These changes include decreases in terrestrial palynomorph abundance and diversity as well as dinoflagellate assemblages that reflect colder sea surface temperatures and increased glaciation (Warny and Askin, 2011). Understanding the factors controlling these changes in climate and vegetation is a topic of great interest. One area of remaining uncertainty is how the hydrologic regime varied during Antarctica's shift from greenhouse to icehouse conditions. For example, estimates of Antarctic precipitation from around the E-O boundary based on plant leaf margins (e.g. Francis et al., 2008), clay mineralogy (e.g. Christian and Kennett, 1997), and models (Thorn and DeConto 2006) are vastly different. We used a moving-wire device interfaced with an isotope-ratio mass spectrometer (Sessions et al., 2005; Nelson et al., 2008) to analyze δ13C of small quantities of Nothofagus sporopollenin extracted from Antarctic Eocene SHALDRIL cores from ~35.9 Mya, just prior to the E-O Boundary (Bohaty et al., 2011). We also analyzed δ13C of modern Nothofagus sporopollenin from herbaria specimens and related these results to historical climate data. Our modern data show that carbon isotope discrimination (Δ) of Nothofagus sporopollenin is positively correlated with mean annual and growing-season precipitation, consistent with prior studies that demonstrate a strong relationship between Δ and water availability in C3 plants. Eocene Nothofagus Δ values progressively decreased through time, implying a decline in moisture availability. There is a close correlation between Nothofagus palynomorph abundance (Warny and Askin, 2011) and Δ, indicating that Nothofagus abundance declined in response to decreasing moisture availability. We consider changes in sea surface temperatures as well as increased glaciation as possible causes behind these changes in aridity.

  12. Use of Nanostructure-Initiator Mass Spectrometry to Deduce Selectivity of Reaction in Glycoside Hydrolases

    PubMed Central

    Deng, Kai; Takasuka, Taichi E.; Bianchetti, Christopher M.; Bergeman, Lai F.; Adams, Paul D.; Northen, Trent R.; Fox, Brian G.

    2015-01-01

    Chemically synthesized nanostructure-initiator mass spectrometry (NIMS) probes derivatized with tetrasaccharides were used to study the reactivity of representative Clostridium thermocellum β-glucosidase, endoglucanases, and cellobiohydrolase. Diagnostic patterns for reactions of these different classes of enzymes were observed. Results show sequential removal of glucose by the β-glucosidase and a progressive increase in specificity of reaction from endoglucanases to cellobiohydrolase. Time-dependent reactions of these polysaccharide-selective enzymes were modeled by numerical integration, which provides a quantitative basis to make functional distinctions among a continuum of naturally evolved catalytic properties. Consequently, our method, which combines automated protein translation with high-sensitivity and time-dependent detection of multiple products, provides a new approach to annotate glycoside hydrolase phylogenetic trees with functional measurements. PMID:26579511

  13. A Model for Carbohydrate Metabolism in the Diatom Phaeodactylum tricornutum Deduced from Comparative Whole Genome Analysis

    PubMed Central

    Kaplan, Aaron; Caron, Lise; Weber, Till; Maheswari, Uma; Armbrust, E. Virginia; Bowler, Chris

    2008-01-01

    Background Diatoms are unicellular algae responsible for approximately 20% of global carbon fixation. Their evolution by secondary endocytobiosis resulted in a complex cellular structure and metabolism compared to algae with primary plastids. Methodology/Principal Findings The whole genome sequence of the diatom Phaeodactylum tricornutum has recently been completed. We identified and annotated genes for enzymes involved in carbohydrate pathways based on extensive EST support and comparison to the whole genome sequence of a second diatom, Thalassiosira pseudonana. Protein localization to mitochondria was predicted based on identified similarities to mitochondrial localization motifs in other eukaryotes, whereas protein localization to plastids was based on the presence of signal peptide motifs in combination with plastid localization motifs previously shown to be required in diatoms. We identified genes potentially involved in a C4-like photosynthesis in P. tricornutum and, on the basis of sequence-based putative localization of relevant proteins, discuss possible differences in carbon concentrating mechanisms and CO2 fixation between the two diatoms. We also identified genes encoding enzymes involved in photorespiration with one interesting exception: glycerate kinase was not found in either P. tricornutum or T. pseudonana. Various Calvin cycle enzymes were found in up to five different isoforms, distributed between plastids, mitochondria and the cytosol. Diatoms store energy either as lipids or as chrysolaminaran (a β-1,3-glucan) outside of the plastids. We identified various β-glucanases and large membrane-bound glucan synthases. Interestingly most of the glucanases appear to contain C-terminal anchor domains that may attach the enzymes to membranes. Conclusions/Significance Here we present a detailed synthesis of carbohydrate metabolism in diatoms based on the genome sequences of Thalassiosira pseudonana and Phaeodactylum tricornutum. This model provides novel insights into acquisition of dissolved inorganic carbon and primary metabolic pathways of carbon in two different diatoms, which is of significance for an improved understanding of global carbon cycles. PMID:18183306

  14. Glycan specificity of myelin-associated glycoprotein and sialoadhesin deduced from interactions with synthetic oligosaccharides.

    PubMed

    Strenge, K; Schauer, R; Bovin, N; Hasegawa, A; Ishida, H; Kiso, M; Kelm, S

    1998-12-01

    Myelin-associated glycoprotein (MAG) and sialoadhesin (Sn) bind to sialylated glycans on cell surfaces and are thought to be involved in cell-cell interactions. In order to investigate how the interactions of these proteins are influenced by the glycan structure, we compared the inhibitory potencies of different synthetic monovalent oligosaccharides and polyvalent polyacrylamide derivatives. Using oligosaccharides with modifications in the sialic acid, galactose or N-acetylglucosamine moieties, we could demonstrate that both MAG and Sn bind with high preference to alpha2,3-linked sialic acid and interact at least with the three terminal monosaccharide units. For MAG, contacts with even more distant monosaccharides are likely, since pentasaccharides are bound better than trisaccharides. Also, an additional sialic acid at position six of the third-terminal monosaccharide unit enhances binding to MAG, whereas it does not influence binding to Sn significantly. Modifications of the sialic acid glycerol side chain demonstrated that the hydroxy groups at positions 8 and 9 are required for binding to both proteins. Surprisingly, MAG binds 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid significantly better than N-acetylneuraminic acid, whereas Sn prefers the latter structure. These results indicate that the interactions of MAG and Sn are mainly with sialic acid and that additional contacts with the subterminal galactose and N-acetylglucosamine residues also contribute to the binding strength, although to a lesser degree. PMID:9874234

  15. Eastern Asian Emissions of Anthropogenic Halocarbons Deduced from Aircraft Concentration Data

    NASA Technical Reports Server (NTRS)

    Palmer, Paul I.; Jacob, Daniel J.; Mickle, Loretta, J.; Blake, Donald R.; Sachse, Glen W.; Fuelberg, Henry E.; Kiley, Christopher M.

    2003-01-01

    The Montreal Protocol restricts production of ozone-depleting halocarbons worldwide. Enforcement of the protocol has relied mainly on annual government statistics of production and consumption of these compounds (bottom-up approach). We show here that aircraft observations of ha1ocarbon:CO enhancement ratios on regional to continental scales can be used to infer halocarbon emissions, providing independent verification of the bottom-up approach. We apply this topdown approach to aircraft observations of Asian outflow &om the TRACE-P mission over the western Pacific (March-April 2001) and derive emissions from eastern Asia (China, Japan, and Korea). We derive an eastern Asian carbon tetrachloride (CCl4) source of 21.5 Gg yr(sup -1), several-fold larger than previous estimates and amounting to -30% of the global budget for this gas. Our emission estimate for CFC-11 from eastern Asia is 50% higher than inventories derived from manufacturing records. Our emission estimates for methyl chloroform (CH3CC13) and CFC-12 are in agreement with existing inventories. For halon 1211 we find only a strong local source originating from the Shanghai area. Our emission estimates for the above gases result in a approximately equal to 40% increase in the ozone depletion potential (ODP) of Asian emissions relative to previous estimates, corresponding to a approximately equal to 10% global increase in ODP.

  16. Evolution of green plants as deduced from 5S rRNA sequences

    PubMed Central

    Hori, Hiroshi; Lim, Byung-Lak; Osawa, Syozo

    1985-01-01

    We have constructed a phylogenic tree for green plants by comparing 5S rRNA sequences. The tree suggests that the emergence of most of the uni- and multicellular green algae such as Chlamydomonas, Spirogyra, Ulva, and Chlorella occurred in the early stage of green plant evolution. The branching point of Nitella is a little earlier than that of land plants and much later than that of the above green algae, supporting the view that Nitella-like green algae may be the direct precursor to land plants. The Bryophyta and the Pteridophyta separated from each other after emergence of the Spermatophyta. The result is consistent with the view that the Bryophyta evolved from ferns by degeneration. In the Pteridophyta, Psilotum (whisk fern) separated first, and a little later Lycopodium (club moss) separated from the ancestor common to Equisetum (horsetail) and Dryopteris (fern). This order is in accordance with the classical view. During the Spermatophyta evolution, the gymnosperms (Cycas, Ginkgo, and Metasequoia have been studied here) and the angiosperms (flowering plants) separated, and this was followed by the separation of Metasequoia and Cycas (cycad)/Ginkgo (maidenhair tree) on one branch and various flowering plants on the other. PMID:16593540

  17. Evolution of green plants as deduced from 5S rRNA sequences.

    PubMed

    Hori, H; Lim, B L; Osawa, S

    1985-02-01

    We have constructed a phylogenic tree for green plants by comparing 5S rRNA sequences. The tree suggests that the emergence of most of the uni- and multicellular green algae such as Chlamydomonas, Spirogyra, Ulva, and Chlorella occurred in the early stage of green plant evolution. The branching point of Nitella is a little earlier than that of land plants and much later than that of the above green algae, supporting the view that Nitella-like green algae may be the direct precursor to land plants. The Bryophyta and the Pteridophyta separated from each other after emergence of the Spermatophyta. The result is consistent with the view that the Bryophyta evolved from ferns by degeneration. In the Pteridophyta, Psilotum (whisk fern) separated first, and a little later Lycopodium (club moss) separated from the ancestor common to Equisetum (horsetail) and Dryopteris (fern). This order is in accordance with the classical view. During the Spermatophyta evolution, the gymnosperms (Cycas, Ginkgo, and Metasequoia have been studied here) and the angiosperms (flowering plants) separated, and this was followed by the separation of Metasequoia and Cycas (cycad)/Ginkgo (maidenhair tree) on one branch and various flowering plants on the other. PMID:16593540

  18. Students' Dilemmas in Reaction Stoichiometry Problem Solving: Deducing the Limiting Reagent in Chemical Reactions

    ERIC Educational Resources Information Center

    Chandrasegaran, A. L.; Treagust, David F.; Waldrip, Bruce G.; Chandrasegaran, Antonia

    2009-01-01

    A qualitative case study was conducted to investigate the understanding of the limiting reagent concept and the strategies used by five Year 11 students when solving four reaction stoichiometry problems. Students' written problem-solving strategies were studied using the think-aloud protocol during problem-solving, and retrospective verbalisations…

  19. Outbreaks of Yuzu Dieback in Goheung Area: Possible Causes Deduced from Weather Extremes

    PubMed Central

    Kim, Kwang-Hyung; Kim, Gyoung Hee; Son, Kyeong In; Koh, Young Jin

    2015-01-01

    Starting in 2012, severe diebacks usually accompanied by abundant gum exudation have occurred on yuzu trees in Goheung-gun, Jeonnam Province, where severely affected trees were occasionally killed. On-farm surveys were conducted at 30 randomly-selected orchards located at Pungyang-myeon, Goheung-gun, and the resulting disease incidences were 18.5% and 39.6% for dieback and gumming symptoms, respectively. Black spots on branches and leaves also appeared on infected trees showing a typical dieback symptom. Morphological and molecular identifications of the isolated fungal organisms from lesions on the symptomatic leaves and branches revealed that they are identical to Phomopsis citri, known to cause gummosis. In order to find the reason for this sudden epidemic, we investigated the weather conditions that are exclusively distinct from previous years, hypothesizing that certain weather extremes might have caused the severe induction of pre-existing disease for yuzu. There were two extreme temperature drops beyond the yuzu’s cold hardiness limit right after an abnormally-warm-temperature-rise during the winter of 2011–12, which could cause severe frost damage resulting in mechanical injuries and physiological weakness to the affected trees. Furthermore, there was an increased frequency of strong wind events, seven times in 2012 compared to only a few times in the previous years, that could also lead to extensive injuries on branches. In conclusion, we estimated that the possible damages by severe frost and frequent strong wind events during 2012 could cause the yuzu trees to be vulnerable to subsequent fungal infection by providing physical entries and increasing plant susceptibility to infections. PMID:26361477

  20. Analysis of satellite data to deduce stratospheric constituents and UV spectroscopic properties of the atmosphere

    NASA Technical Reports Server (NTRS)

    Mcpeters, Richard D.

    1990-01-01

    The objective is to better understand the stratosphere, its constituents, and its ultraviolet optical properties, through detailed analysis of data from the SBUV instrument on Nimbus 7 and comparison with data from other instruments, including the NOAA 9 SBUV 2, SAGE, SME, and SMM. One conclusion to be drawn from the Ozone Trends Panel report is that there are unresolved differences in the ozone profiles measured by different instruments. While the purpose of the work is more to understand the details of the UV radiation field in the stratosphere than it is to assess the accuracy of the SBUV ozone measurement itself, improved understanding of specific problems in the UV will lead to more accurate ozone retrievals. Areas of study include the effect of aerosols on the backscattered albedo, the shape of the ozone profile near the stratopause, the effect of possible polar mesospheric clouds, and the measureability of nitric oxide and sulfur dioxide.

  1. Holocene oceanographic and climatic variability of the Vega Drift deduced through foraminiferal interpretation

    USGS Publications Warehouse

    Szymcek, Phillip; Ishman, Scott E.; Domack, Eugene W.; Leventer, Amy

    2007-01-01

    fusiformis assemblages. Most agglutinated forms tend to decrease downcore, and comparisons to modern analogues imply post-depositional disintegration, while calcareous taxa indicate non-corrosive bottom waters. The lower to middle Holocene Vega Drift sediments are characterized by the calcareous S. fusiformis assemblage and glacial plume sediments. This assemblage is characterized by calcareous forms including Globocassidulina biora, G. subglobosa, and Nonionella iridea. The planktic species Neogloboquadrina pachyderma is associated with the S. fusiformis assemblage. The S. fusiformis assemblage is faunally similar to assemblages described in fjords of the western Antarctic Peninsula and indicates non-corrosive bottom water. Sediments of the mid to upper Holocene interval are characterized by the T. wiesneri and M. arenacea assemblages and indicate the presence of Hyper Saline Shelf Water. These assemblages are similar to modern assemblages directly to the south in the Prince Gustav Channel. The upper Holocene is marked by several small intervals with taxonomic characteristics similar to the S. fusiformis assemblage, indicating periodic introduction of non-corrosive bottom water to the Vega Drift

  2. Low Angle Contact Between the Oaxaca and Juárez Terranes Deduced From Magnetotelluric Data

    NASA Astrophysics Data System (ADS)

    Arzate-Flores, Jorge A.; Molina-Garza, Roberto; Corbo-Camargo, Fernando; Márquez-Ramírez, Víctor

    2016-04-01

    We present the electrical resistivity model along a profile perpendicular to the Middle America trench in southern Mexico that reveals previously unrecognized tectonic features at upper to mid-crustal depths. Our results support the hypotheses that the upper crust of the Oaxaca terrane is a residual ~20 km thick crust composed by an ~10 km thick faulted crustal upper layer and an ~10 km thick hydrated and/or mineralized layer. Oaxaca basement overthrust the younger Juárez (or Cuicateco) terrane. The electrical resistivity model supports the interpretation of a slab subducting at a low angle below Oaxaca. Uplift in the Oaxaca region appears to be related to fault reactivation induced by low angle subduction. In the Juárez terrane, isostatic forces may contribute to uplift because it is largely uncompensated. In the Sierra Madre del Sur, closer to the coast, uplift is facilitated by slab-dehydration driven buoyancy. Both gravity and resistivity models are consistent with a thinned upper crust in the northeast end of the profile.

  3. Conformational model of the Holliday junction transition deduced from molecular dynamics simulations

    PubMed Central

    Yu, Jin; Ha, Taekjip; Schulten, Klaus

    2004-01-01

    Homologous recombination plays a key role in the restart of stalled replication forks and in the generation of genetic diversity. During this process, two homologous DNA molecules undergo strand exchange to form a four-way DNA (Holliday) junction. In the presence of metal ions, the Holliday junction folds into the stacked-X structure that has two alternative conformers. Experiments have revealed the spontaneous transitions between these conformers, but their detailed pathways are not known. Here, we report a series of molecular dynamics simulations of the Holliday junction at physiological and elevated (400 K) temperatures. The simulations reveal new tetrahedral intermediates and suggest a schematic framework for conformer transitions. The tetrahedral intermediates bear resemblance to the junction conformation in complex with a junction-resolving enzyme, T7 endonuclease I, and indeed, one intermediate forms a stable complex with the enzyme as demonstrated in one simulation. We also describe free energy minima for various states of the Holliday junction system, which arise during conformer transitions. The results show that magnesium ions stabilize the stacked-X form and destabilize the open and tetrahedral intermediates. Overall, our study provides a detailed dynamic model of the Holliday junction undergoing a conformer transition. PMID:15613597

  4. The origin of GEMS in IDPs as deduced from microstructural evolution of amorphous silicates with annealing

    NASA Astrophysics Data System (ADS)

    Davoisne, C.; Djouadi, Z.; Leroux, H.; D'Hendecourt, L.; Jones, A.; Deboffle, D.

    2006-03-01

    Aims.We present laboratory studies of the micro-structural evolution of an amorphous ferro-magnesian silicate, of olivine composition, following thermal annealing under vacuum.Methods.The amorphous silicate was prepared as a thin film on a diamond substrate. Annealing under vacuum was performed at temperatures ranging from 870 to 1020 K. After annealing the thin films were extracted from the substrate and analysed by transmission electron microscopy to infer their microstructural and compositional evolution.Results.Spheroidal metallic nano-particles (2-50 nm) are found within the silicate films, which are still amorphous after annealing at 870 K and partially crystallized into forsterite for annealing up to 1020 K. We interpret this microstructure in terms of a reduction of the initial amorphous silicate FeO component, because of the carbon-rich partial pressure in the furnace due to pumping mechanism. Annealing in a controlled oxygen-rich atmosphere confirms this interpretation. Conclusions.The observed microstructures closely resemble those of the GEMS (Glass with Embedded Metal and Sulphides) found in chondritic IDPs (Interplanetary Dust Particles). Since IDPs contain abundant carbonaceous matter, a solid-state reduction reaction may have occurred during heating in the hot inner regions of the proto-solar disc. Related to this, the presence of forsterite grains grown from the amorphous precursor material clearly demonstrates that condensation from gaseous species is not required to explain the occurrence of forsterite around young protostars and in comets. Forsterite grains in these environments can be formed directly in the solid phase by thermal annealing of amorphous ferro-magnesian silicates precursor under reducing conditions. Finally, locking iron as metallic particles within the silicates explains why astronomical silicates always appear observationally Mg-rich.

  5. Topoclimatic features as deduced from remote sensing and their impacts on ecological systems

    NASA Astrophysics Data System (ADS)

    Lensky, Itamar; Dayan, Uri

    2010-05-01

    Several recent studies have shown that global models are not capable to predict accurately the evolution of climate changes and variability on the regional scale. Misinterpretation of the anticipated climate change impacts on plants and animals are caused by failure of models to capture topoclimatic conditions. In order to capture the climate spatial variability induced by topography it is necessary to conduct topoclimatological studies. The steady growth in remote sensing and its capacities to monitor spatial patterns in climate driven by topography seems to be an indispensable tool to fill the spatial gap existing in topoclimatic studies. We analyzed time series of Land Surface Temperature (LST) from MODerate resolution Imaging Spectroradiometer (MODIS) on NASA's TERRA satellite using temporal Fourier analysis for the Eastern Mediterranean (EM). RGB display of the mean, amplitude and phase of the first harmonic (annual) were used to decipher topoclimatic features, e.g. cold patches of few kilometers differing much from their vicinity, driven by local topography. These time series were also used to calculate recent decadal trends on a fine spatial resolution of 1 km. The decadal trend over the EM is of about 0.3oC with very large local variability (-1.5 to 1.5oC). The day LST trends values are larger than those obtained for the night time, implying tendency towards a more continental climate (desertification). The thermal heterogeneity resulting from topographic diversity has strong impacts on ecological systems (e.g. biodiversity) and on agriculture (e.g. pest management, crop production). Examples of such impacts will be shown for present and predicted climate for 20 years over the EM.

  6. Crustal structure of the Hecataeus Rise (eastern Mediterranean) deduced by marine gravity and marine magnetic modelling

    NASA Astrophysics Data System (ADS)

    Dehghani, Ali

    2016-04-01

    In the year 2010 extensive geophysical researches were carried out in the area of Hecataeus Rise using the German research vessel Maria S. Merian. Beside the bathymetry, refraction and reflection seismic data, marine gravity and marine magnetic data were acquired during this cruise. The result of the research along one Wide-Angle reflection/refraction seismic line of this cruise is published 2015 by K. Welford et al.. Based on interpretation of reflection seismic and bathymetry data across the Hecataeus Rise, S. Reiche published 2015 the crustal structure and bathymetric features along some seismic profiles of this cruise. The focus of this work is to use the available sediments and crustal structures inferred by seismic information together with real marine gravity and marine magnetic data in order to produce gravity and magnetic 2-D models along all seismic profiles. While Welford et al. used the altimetry gravity data and magnetic data from EMAG3 database for their modelling, the real gravity and magnetic data measured exactly along the seismic profiles will be used in this work. The advantage of the real marine gravity and real marine magnetic data used for the modelling is that they have higher accuracy in the values as well as in the positions. Furthermore, Welford et al. calculated the gravity and Magnetic models along some seismic profiles, while in this work the result of gravity and magnetic modelling along all seismic profiles of this cruise will be presented. The marine gravity and marine magnetic data along all seismic profiles were recorded continuously. The accuracy of marine gravity data is about ± 1 mGal, while the accuracy of Marine magnetic data is in the range of ± 3 nT. The results of 2-D gravity and magnetic modelling will be presented and discussed in this work.

  7. Using Measurements of Fill Factor at High Irradiance to Deduce Heterobarrier Band Offsets: Preprint

    SciTech Connect

    Olson, J. M.; Steiner, M. A.; Kanevce, A.

    2011-07-01

    Using a 2D device simulation tool, we examine the high irradiance behavior of a single junction, GaAs concentrator cell as a function of the doping in the back surface confinement layer. The confinement layer is designed to be a barrier for both holes and electrons in the base of the solar cell. For a p-type base we show that the FF of the cell at high concentrations is a strong function of both the magnitude of the valence band offset and the doping level in the barrier. In short, for a given valence band offset (VBO), there is a critical barrier doping, below which the FF drops rapidly with lower doping. This behavior is confirmed experimentally for a GaInP/GaAs double heterostructure solar cell where the critical doping concentration (at 500 suns) in the back surface confinement layer is ~1e18 cm-3 for a VBO of 300 meV.

  8. Phase lag deduced information in photo-thermal actuation for nano-mechanical systems characterization

    SciTech Connect

    Bijster, R. J. F. Vreugd, J. de; Sadeghian, H.

    2014-08-18

    In photo-thermal actuation, heat is added locally to a micro-cantilever by means of a laser. A fraction of the irradiation is absorbed, yielding thermal stresses and deformations in the structure. Harmonic modulation of the laser power causes the cantilever to oscillate. Moreover, a phase lag is introduced which is very sensitive to the spot location and the cantilever properties. This phase lag is theoretically predicted and experimentally verified. Combined with thermo-mechanical properties of the cantilever and its geometry, the location of the laser spot, the thermal diffusivity, and the layer thicknesses of the cantilever can be extracted.

  9. Climatological Aspects of Aerosol Physical Characteristics in Tunisia Deduced from Sun Photometric Measurements

    PubMed Central

    Chaâbane, Mabrouk; Azri, Chafai; Medhioub, Khaled

    2012-01-01

    Atmospheric and climatic data measured at Thala site (Tunisia) for a long-time period (1977–2001) are used to analyse the monthly, seasonal, and annual variations of the aerosol optical depth at 1 μm wavelength. We have shown that aerosol and microphysical properties and the dominating aerosol types depend on seasons. A comparison of the seasonal cycle of aerosol optical characteristics at Thala site showed that the contribution of long-range transported particles is expected to be larger in summer as a consequence of the weather stability typical of this season. Also, the winter decrease in atmospheric turbidity may result from increases in relative humidity and decreases in temperature, leading to increased particle size and mass and increased fall and deposition velocities. The spring and autumn weather patterns usually carry fine dust and sand particles for the desert area to Thala region. The annual behaviour of the aerosol optical depth recorded a period of stead increase started in 1986 until 2001. Trends in atmospheric turbidity after 1988 could be explained other ways by the contribution of the eruption of Mount Pinatubo in 1991 and by local or regional changes in climate or in aerosol emissions. PMID:22629150

  10. Origins of light trans-Fe and r-process elements deduced from Galactic chemical evolution

    NASA Astrophysics Data System (ADS)

    Ishimaru, Yuhri; Arao, Sachie; Wanajo, Shinya; Prantzos, Nicolas

    2014-09-01

    Compact binary mergers are suggested to be the major site of the r-process elements by recent hydrodynamical and nucleosynthesis studies. It has been pointed out, however, that estimated long lifetimes of compact binaries are in conflict with the presence of large scatters in r-process elements of very metal-poor stars (MPS). To resolve this problem, we examine the role of compact binary mergers in the early Galactic chemical evolution on the assumption that our Galactic halo was formed from clusterings of sub-halos. We find that star-to-star scatters of [r/Fe] in MPS can be well explained with this scenario. Observations of MPS also show large enhancement of Sr relative to Ba, suggesting a distinct site of light trans-Fe elements. Recent nucleosynthesis studies show that electron-capture supernovae (ECSNe) can produce heavy elements up to Zr (Wanajo et al. 2011). Using our inhomogeneous chemical evolution model, we discuss that ECSNe can explain observed enhancement of Zn in MPS as well as of Sr, Y, and Zr.

  11. Temporal Changes in Eruption Dynamics at Tungurahua Volcano Deduced from Infrasonic Measurements, June 2009

    NASA Astrophysics Data System (ADS)

    Parmigiani, A.; Chojnicki, K. N.; Parcheta, C. E.; Christensen, B.; Marcillo, O. E.; Johnson, J. B.

    2009-12-01

    Tungurahua volcano (1.45S, 78.43W, 5023m), located in the heart of the Andes and within Ecuador's Eastern Cordillera, is the most active populated volcano in the region. Since 1999 Tungurahua has affected the communities on its western flanks with a continuous cycle of Strombolian and Vulcanian activity (VEI 0 and 1) that climaxed on August 16th, 2006 with a VEI 2 event. Continuous tracking of Tungurahua eruptive activity presents a challenge as inclement weather often prevents direct observation of eruptive activity and strong volcanic tremor often masks seismic signals associated with explosive events. Infrasound signals have thus proven invaluable in identifying explosive activity and estimating erupted flux at Tungurahua. During a 10-day-long campaign in June 2009, two temporary arrays (a seismo-acoustic array at 6 km and an acoustic array at 11.5 km) were installed to provide insight into temporal changes in eruption dynamics and near-vent conditions. During the deployment interval, explosive activity was dominated by impulsive infrasonic events. Time-lapse camera footage confirmed Strombolian-style eruptions associated with 77 impulsive events, recorded at an average rate of 8 explosions per day. Columns with variable ash content rose from 2-6 km above the crater rim and incandescent blocks were seen to rise up to 800 meters in altitude during some events. Corresponding infrasonic waveforms had peak pressures as great as 74 Pa at 6 km from the vent and the primary pulses lasted 6-10s. Waveform shapes often displayed high levels of self-similarity in contrast to their seismic counterparts, which persisted up to 40-50s and were emergent and dis-similar. Acoustic array beam-forming and semblance analyses have been employed to decompose the infrasonic wave field, verify volcano acoustic sources, construct a volcano acoustic catalogue, and identify apparent variations in the lateral position of the vent(s). The ratio of elastic energy propagated into the atmosphere relative to energy into the earth is also studied and shown to be variable, suggesting a narrow, dynamic conduit whose geometry and/or eruption mechanism changes between eruption pulses. Finally, mass flux is determined from infrasound N-waves at the beginning of the most vigorous cannon-shot eruptions. This analysis provides insight into the volume of gas that is explosively released at the onset of a discrete explosion.

  12. Ozone profiles and chemical loss rates in the tropical stratosphere deduced from backscatter ultraviolet measurements

    NASA Technical Reports Server (NTRS)

    Frederick, J. E.; Hays, P. B.; Guenther, B. W.; Heath, D. F.

    1978-01-01

    Analysis of data obtained by the backscatter ultraviolet (BUV) experiment on the Atmosphere Explorer E satellite has provided equatorial ozone mixing ratio profiles for equinox and solstice conditions. The combination of these results with a pure oxygen chemical model yields the rate of odd oxygen loss due to the sum of the odd hydrogen, nitrogen, and chlorine cycles. Use of recent mid-latitude stratospheric measurements of HO(x), NO(x), and ClO(x) with the BUV data provides an independent calculation of the catalytic loss. Below 45 km the agreement between the two sets of loss rates is satisfactory. At higher altitudes the odd hydrogen cycle provides far more O(x) loss than can be tolerated by the BUV measurements if the photodissociation of O2 is the only source and has the currently accepted magnitude. The results suggest either a tropical HO(x) concentration smaller than is now believed or the presence of a very large source of odd oxygen in the upper stratosphere and lower mesosphere.

  13. Multiquasiparticle configuration effects deduced from the very high frequency discrete lines spectroscopy of /sup 165/Yb

    SciTech Connect

    Schuck, C.; Bendjallah, N.; Diamond, R.M.; Ellis-Akovali, Y.; Lindenberg, K.H.; Newton, J.O.; Shih, S.; Stephens, F.S.; Garret, J.D.; Herskind, B.

    1982-01-01

    New experimental data are presented for /sup 165/Yb in which three already known rotational bands are extended up to very high angular frequencies. We do not observe, below h-bar omega/sub c/ approx. 0.45 MeV in any of these three bands the second discontinuity occuring for h-bar omega/sub c/ approx. 0.42 MeV in N = 90 nuclei. Furthermore, we observe in these three sequences a dealignment of high enough amplitude that it cannot be explained in terms of a single quasi-neutron configuration, and must then be due to a collective effect. A gradual decrease of the neutron pairing with increasing angular frequencies is suggested.

  14. Deducing Weathering Processes Using Silicon Isotopes in the Ganges Alluvial Plain, India

    NASA Astrophysics Data System (ADS)

    Frings, P.; De La Rocha, C. L.; Fontorbe, G.; Chakrapani, G.; Clymans, W.; Conley, D. J.

    2014-12-01

    The Ganges Alluvial Plain ('GAP') is the sedimentary infill of the foreland basin created during Himalayan orogeny. Freshly eroded material from the Himalaya and southern cratonic tributaries is deposited into a system with long water-sediment interaction times, creating potential for further generation of river weathering fluxes. To quantify weathering processes in the GAP, 51 sites including all major tributaries were sampled in a September 2013 campaign and analysed for major and minor ions, Ge/Si ratios and δ30Si, δ13C and δ18O. Net dissolved Si (DSi) and major cation yields are 2 to 5 times lower in the GAP than the Himalaya, and at a whole basin scale approximate the global average, indicating that the plain apparently moderates the efficiency of Himalayan weathering rates. Mainstem δ30Si spans 0.81 to 1.93‰ (see figure) and gives the impression of a system buffered to moderate DSi and δ30Si. Ge/Si ratios (µmol/mol) are higher than expected in the Himalaya (>3), reflecting input of Ge-enriched water from hot springs, and decline to ~1.4 in the GAP. For the Himalayan sourced rivers, δ30Si increases with distance from the Himalayan front, and can not be explained entirely by conservative mixing with higher δ30Si peninsular and GAP streams. To a first degree, the δ30Si data suggest incorporation of Si into secondary minerals as the key fractionating process, and that this occurs both in situ during initial weathering and progressively in the GAP. Partitioning of solutes between sources is complicated in the GAP. Consistent with previous work, carbonate weathering dominates the ion fluxes, but with substantial contributions from saline/alkaline soil salts, the chlorination of wastewater and highly variable rainfall chemistry. Due to these contributions, precisely inferring the input from silicate weathering is difficult. We introduce a novel method to infer silicate-weathering rates that exploits the fractionation of Si during clay formation to account for the loss of DSi from solution.

  15. Aerosol-Precipitation Responses Deduced from Ship tracks as Observed by CloudSat

    NASA Astrophysics Data System (ADS)

    Christensen, M.; Stephens, G. L.

    2011-12-01

    Ship tracks, produced from the exhaust plumes of ocean going vessels were analyzed using the 94-GHZ cloud profiling radar on the CloudSat satellite to examine the precipitation response of marine stratocumulus to changes in aerosol concentration. Ship tracks provide an ideal laboratory to study this response because the regions of clouds that are heavily contaminated by pollution can be separated from adjacent regions of clouds formed in the clean marine boundary layer. Several hundred ship tracks, coinciding with the radar and lidar observations from CloudSat and Calipso, were identified in MODIS imagery. The results demonstrate that, aerosol plumes from ships tend to decrease the spatial extent of rainfall (rain cover fraction) and intensity compared to the nearby pristine clouds. However, there were a substantial fraction of cases (30%), which exhibited increased rainfall. The sign and strength of the precipitation response was strongly tied to the mesoscale structure of the clouds. When the clouds exhibited closed cellular structures, liquid water amount, rainfall (-63%), and rain cover fraction significantly decreased (-55%). These reductions in rainfall were primarily associated with the decrease in rain cover fraction over the ship track domain. The opposite occurred in the open cell regime. Ship plumes ingested into this regime resulted in deeper, wetter, rainier, and brighter clouds, where rainfall increased by 88% primarily due to changes in intensity and to a lesser extent rain cover fraction. Microphysical changes almost always led to significantly smaller droplet radii in ship tracks, even when precipitation was increased. On the other hand, macrophysical changes (liquid water path) varied in magnitude and sign, and typically followed the direction of the precipitation response. The results presented here underline the need to consider the mesoscale structure of stratocumulus when examining the cloud dynamic response to changes in aerosol concentration.

  16. Deducing Shape of Anisotropic Particles in Solution from Light Scattering: Spindles and Nanorods

    NASA Astrophysics Data System (ADS)

    Tsuper, Ilona; Terrano, Daniel; Streletzky, Kiril A.; Dement'eva, Olga V.; Semyonov, Sergey A.; Rudoy, Victor M.

    Depolarized Dynamic Light Scattering (DDLS) enables to measure rotational and translational diffusion of nanoparticles suspended in solution. The particle size, shape, diffusion, and interactions can then be inferred from the DDLS data using various models of diffusion. Incorporating the technique of DDLS to analyze the dimensions of easily imaged elongated particles, such as Iron (III) oxyhydroxide (FeOOH) Spindles and gold Nanorods, allows testing of the models for rotational and translational diffusion of elongated particles in solution. This, in turn, can help to better interpret DDLS data on hard-to-image anisotropic wet systems such as micelles, microgels, and protein complexes. This study focused on FeOOH Spindles and gold nanorod particles. The light scattering results on FeOOH analyzed using the basic model of non-interacting prolate ellipsoids yielded dimensions within 17% of the SEM measured dimensions. The dimensions of gold nanorod obtained from the straight cylinder model of DDLS data provided results within 25% of the sizes that were obtained from TEM. The nanorod DDLS data was also analyzed by a spherocylinder model.

  17. Identification of widespread pollution in the Southern Hemisphere deduced from satellite analyses

    NASA Technical Reports Server (NTRS)

    Fishman, J.; Fakhruzzaman, K.; Cros, B.; Nganga, D.

    1991-01-01

    Vertical profiles of ozone obtained from ozonesondes in Brazzaville (Congo) and Ascension Island show that large quantities of tropospheric ozone are present over southern Africa and the adjacent eastern tropical South Atlantic Ocean. The origin of this pollution is widespread biomass burning in Africa. These measurements support satellite-derived tropospheric ozone data that demonstrate that ozone originating from this region is transported throughout most of the Southern Hemisphere. Seasonally high levels of CO2 and methane observed at middle- and high-latitude stations in Africa, Australia, and Antarctica likely reflect the effects of this distant biomass burning. These data suggest that even the most remote regions on this planet may be significantly more polluted than previously believed.

  18. Plasma drifts deduced from resonance cone asymmetries: II. Evaluation of COREX data

    NASA Astrophysics Data System (ADS)

    Piel, A.; Rohde, V.; Thiemann, H.; Oyama, K. I.

    The data from the COREX instrument are discussed with respect to non-reciprocities in resonance cones for opposing wave propagation directions. The shift of the maxima has a different symmetry from the case of field aligned drifts. Using a generalized drift model the magnitude and direction of the drift is evaluated. Velocities of the order of up to 38 km/s are found. The drift direction is nearly perpendicular to the magnetic field.

  19. Mining a Sea of Data: Deducing the Environmental Controls of Ocean Chlorophyll

    PubMed Central

    Irwin, Andrew J.; Finkel, Zoe V.

    2008-01-01

    Chlorophyll biomass in the surface ocean is regulated by a complex interaction of physiological, oceanographic, and ecological factors and in turn regulates the rates of primary production and export of organic carbon to the deep ocean. Mechanistic models of phytoplankton responses to climate change require the parameterization of many processes of which we have limited knowledge. We develop a statistical approach to estimate the response of remote-sensed ocean chlorophyll to a variety of physical and chemical variables. Irradiance over the mixed layer depth, surface nitrate, sea-surface temperature, and latitude and longitude together can predict 83% of the variation in log chlorophyll in the North Atlantic. Light and nitrate regulate biomass through an empirically determined minimum function explaining nearly 50% of the variation in log chlorophyll by themselves and confirming that either light or macronutrients are often limiting and that much of the variation in chlorophyll concentration is determined by bottom-up mechanisms. Assuming the dynamics of the future ocean are governed by the same processes at work today, we should be able to apply these response functions to future climate change scenarios, with changes in temperature, nutrient distributions, irradiance, and ocean physics. PMID:19043583

  20. Average depth of blood vessels in skin and lesions deduced by optical fiber spectroscopy

    NASA Astrophysics Data System (ADS)

    Jacques, Steven L.; Saidi, Iyad S.; Tittel, Frank K.

    1994-09-01

    The average depth of blood vessels in a cutaneous site, either normal or diseased, can be specified by a simple rapid noninvasive optical measurement. An optical fiber spectrophotometer delivers white light via optical fibers to a skin site. The light reflected by tissue scattering and successfully collected by optical fibers is carried to a diode array spectrophotometer for spectral analysis. The reflectance spectrum is analyzed to specify the component of the optical density (OD) spectrum which is attributed to the cutaneous blood. Then the ratio of the OD420 nm/OD585 nm provides a quantitative indication of the average depth of the blood in the skin site. The purple light (420 nm) less easily penetrates the skin to sample the cutaneous blood content than does the yellow light (585 nm). The calibration of the measurement was accomplished by Monte Carlo simulations of measurements on skin with a layer of blood at various depths. In a study of 47 neonates, the amount of blood content ranged from 4 - 12 mg hemoglobin/g tissue (equivalent to 0.8 - 2.4% of the skin volume being whole blood), and the average depth of blood ranged from 250 - 425 micrometers .

  1. Properties of solar coronal active regions deduced from X-ray line spectra

    NASA Astrophysics Data System (ADS)

    McKenzie, D. L.

    1987-11-01

    Spectra from the SOLEX B RAP spectrometer have been used to analyze the temperature and density structure of over 100 nonflaring solar active regions. Density measurements that used the R ratio of O VII indicated that few regions have electron densities higher than ≡3×109cm-3. In a few cases, flare-productive regions had measured densities approximately twice this high. Temperature-sensitive line ratios in the helium-like ions O VII, Ne IX, and Mg XI were used to decude the general properties of the differential emission-measure function B(T) for nonflaring regions. B(T) falls off with increasing temperature above a peak temperature that is almost always lower than Tm(O VII) = 1.8×106K.

  2. Decadal variability in core surface flows deduced from geomagnetic observatory monthly means

    NASA Astrophysics Data System (ADS)

    Whaler, K. A.; Olsen, N.; Finlay, C. C.

    2016-07-01

    Monthly means of the magnetic field measurements at ground observatories are a key data source for studying temporal changes of the core magnetic field. However, when they are calculated in the usual way, contributions of external (magnetospheric and ionospheric) origin may remain, which make them less favourable for studying the field generated by dynamo action in the core. We remove external field predictions, including a new way of characterising the magnetospheric ring current, from the data and then calculate revised monthly means using robust methods. The geomagnetic secular variation (SV) is calculated as the first annual differences of these monthly means, which also removes the static crustal field. SV time series based on revised monthly means are much less scattered than those calculated from ordinary monthly means, and their variances and correlations between components are smaller. On the annual to decadal timescale, the SV is generated primarily by advection in the fluid outer core. We demonstrate the utility of the revised monthly means by calculating models of the core surface advective flow between 1997 and 2013 directly from the SV data. One set of models assumes flow that is constant over three months; such models exhibit large and rapid temporal variations. For models of this type, less complex flows achieve the same fit to the SV derived from revised monthly means than those from ordinary monthly means. However, those obtained from ordinary monthly means are able to follow excursions in SV that are likely to be external field contamination rather than core signals. Having established that we can find models that fit the data adequately, we then assess how much temporal variability is required. Previous studies have suggested that the flow is consistent with torsional oscillations (TO), solid body-like oscillations of fluid on concentric cylinders with axes aligned along the Earth's rotation axis. TO have been proposed to explain decadal timescale changes in the length-of-day. We invert for flow models where the only temporal changes are consistent with TO, but such models have an unacceptably large data misfit. However, if we relax the TO constraint to allow a little more temporal variability, we can fit the data as well as with flows assumed constant over three months, demonstrating that rapid SV changes can be reproduced by rather small flow changes. Although the flow itself changes slowly, its time derivative can be locally (temporally and spatially) large, in particular when and where core surface secular acceleration peaks. Spherical harmonic expansion coefficients of the flows are not well resolved, and many of them are strongly correlated. Averaging functions, a measure of our ability to determine the flow at a given location from the data distribution available, are poor approximations to the ideal, even when centred on points of the core surface below areas of high observatory density. Both resolution and averaging functions are noticeably worse for the toroidal flow component, which dominates the flow, than the poloidal flow component, except around the magnetic equator where averaging functions for both components are poor.

  3. Vertical profiles of dust and ozone in the Martian atmosphere deduced from solar occultation measurements

    NASA Astrophysics Data System (ADS)

    Blamont, J. E.; Chassefiere, E.; Goutail, J. P.; Mege, B.; Nunes-Pinharanda, M.; Souchon, G.; Krasnopolsky, V. A.; Krysko, A. A.; Moroz, V. I.

    1991-02-01

    The vertical distribution of the ozone content and of the aerosols in the Martian atmosphere at the equinox and near the equator was studied with the aid of a biaxial pointing device, a microprocessor-controlled flat mirror of elliptical shape. An upper limit of 5 x 10 to the 7th mol/cu cm for ozone was obtained above an altitude of 30 km. For the aerosols, a semiquantitative distribution has been obtained between 10 and 50 km of altitude. The scale height is nearly equal to the atmospheric scale height in the 10-20 km region where mixing seems to predominate, and falls rapidly to a thickness of about 2 km at 30 km. In 10 percent of the occultations, a stratified haze has been detected between 40 and 50 km. The particle radius of cloud constituents is estimated and optical thickness per kilometer of these hazes at peak extinction are approximated. An eddy diffusion coefficient and a mixing ratio are estimated for clouds assumed to be at equilibrium.

  4. Coronal structures deduced from photospheric magnetic field and He I lambda 10830 observations

    NASA Technical Reports Server (NTRS)

    Harvey, Karen L.

    1995-01-01

    The National Solar Observatory synoptic program provides an extensive and unique data base of high-resolution full-disk observations of the line-of-sight photospheric magnetic fields and of the He I lambda 10830 equivalent width. These data have been taken nearly daily for more than 21 years since 1974 and provide the opportunity to investigate the behavior of the magnetic fields in the photosphere and those inferred for the corona spanning on the time scales of a day to that of a solar cycle. The intensity of structures observed in He I lambda 10830 are strongly modulated by overlying coronal radiation; areas with low coronal emission are generally brighter in He I lambda 10830, while areas with high coronal emission are darker. For this reason, He I lambda 10830 was selected in the mid-1970's as way to identify and monitor coronal holes, magnetic fields with an open configuration, and the sources of high-speed solar wind streams. The He I lambda 10830 spectroheliograms also show a wide variety of other structures from small-scale, short-lived dark points (less than 30 arc-sec, hours) to the large-scale, long-lived two 'ribbon' flare events that follow the filament eruptions (1000 arc-sec, days). Such structures provide clues about the connections and changes in the large-scale coronal magnetic fields that are rooted in concentrations of magnetic network and active regions in the photosphere. In this paper, what observations of the photospheric magnetic field and He I lambda 10830 can tell us about the short- and long-term evolution of the coronal magnetic fields will be discussed, focussing on the quiet Sun and coronal holes. These data and what we infer from them will be compared with direct observations of the coronal structure from the Yohkoh Soft X-ray Telescope.

  5. Dipole-Strength Distributions up to the Giant Dipole Resonance Deduced from Photon Scattering

    NASA Astrophysics Data System (ADS)

    Schwengner, R.; Rusev, G.; Benouaret, N.; Beyer, R.; Dönau, F.; Erhard, M.; Grosse, E.; Junghans, A. R.; Kosev, K.; Klug, J.; Nair, C.; Nankov, N.; Schilling, K. D.; Wagner, A.

    2008-04-01

    Dipole-strength distributions up to the neutron-separation energies of the even-mass Mo isotopes from 92Mo to 100Mo and of the N = 50 isotones 88Sr, 89Y, 90Zr have been investigated in photon-scattering experiments using the bremsstrahlung facility at the superconducting electron accelerator ELBE of the Forschungszentrum Dresden-Rossendorf. A measurement using polarised bremsstrahlung impinging on 88Sr revealed that all resolved transitions with energies greater than 6 MeV in this nuclide except for one are E1 transitions. The intensity distributions obtained from the measured spectra after a correction for detector response and a subtraction of atomic background in the target contain a continuum part in addition to the resolved peaks. It turns out that the dipole strength in the resolved peaks amounts to about 30% of the total dipole strength while the continuum contains about 70%. In order to estimate the distribution of inelastic transitions and to correct the ground-state transitions for their branching ratios simulations of γ-ray cascades were performed. The photoabsorption cross sections obtained in this way connect smoothly to (γ, n) cross sections and give novel information about the strength on the low-energy tails of the Giant Dipole Resonances below the neutron-separation energies. The experimental cross sections are compared with predictions of a Quasiparticle-Random-Phase Approximation in a deformed basis. The calculations describe the experimentally observed increase of the dipole strengths with increasing neutron number of the Mo isotopes as a consequence of increasing nuclear deformation.

  6. Climatological aspects of aerosol physical characteristics in Tunisia deduced from sun photometric measurements.

    PubMed

    Chaâbane, Mabrouk; Azri, Chafai; Medhioub, Khaled

    2012-01-01

    Atmospheric and climatic data measured at Thala site (Tunisia) for a long-time period (1977-2001) are used to analyse the monthly, seasonal, and annual variations of the aerosol optical depth at 1 μm wavelength. We have shown that aerosol and microphysical properties and the dominating aerosol types depend on seasons. A comparison of the seasonal cycle of aerosol optical characteristics at Thala site showed that the contribution of long-range transported particles is expected to be larger in summer as a consequence of the weather stability typical of this season. Also, the winter decrease in atmospheric turbidity may result from increases in relative humidity and decreases in temperature, leading to increased particle size and mass and increased fall and deposition velocities. The spring and autumn weather patterns usually carry fine dust and sand particles for the desert area to Thala region. The annual behaviour of the aerosol optical depth recorded a period of stead increase started in 1986 until 2001. Trends in atmospheric turbidity after 1988 could be explained other ways by the contribution of the eruption of Mount Pinatubo in 1991 and by local or regional changes in climate or in aerosol emissions. PMID:22629150

  7. Coseismic and Postseismic slip distribution of the 2007 Solomon Islands Earthquake deduced from A Bayesian Inversion

    NASA Astrophysics Data System (ADS)

    Chen, T.; Gong, X.

    2011-12-01

    In inversion of geodetic data for distribution of fault slip minimizing the first or second order derivatives of slip across fault plane is generally employed to smooth slips of neighboring patches.Smoothing parameter is subjective selected to determine the relative weight placed on fitting data versus smoothing the slip distribution.We use the Fully Bayesian Inversion method(Fukuda,2008)to simultaneously estimate the slip distribution and smoothing parameter objectively in a Bayesian framework. The distributed slips,the posterior probability density function and the smoothing parameter is formulated with Bayes' theorem and sampled with a Markov chain Monte Carlo method. Here We will apply this method to Coseismic and Postseismic displacement data from the 2007 Solomon Islands Earthquake and compare the results of this method with generally favored method.

  8. Wheat - Its growth and disease severity as deduced from ERTS-1

    NASA Technical Reports Server (NTRS)

    Kanemasu, E. T.; Niblett, C. L.; Manges, H.; Lenhert, D.; Newman, M. A.

    1974-01-01

    The spectral reflectance of a cropped surface changes as the plant develops. An indicator of crop growth is leaf area index (ratio of green leaf area to soil area). The leaf area index, disease severity, and yield were determined for several winter wheat fields in Kansas during the 1973 growing season. Multispectral scanner (MSS) data from Earth Resources Technology Satellite-1 (ERTS-1) showed a high correlation (r greater than or equal to 0.90) between crop growth and MSS4/MSS5, and crop growth and MSS5/MSS6. Wheat disease severity and yields were significantly correlated at the 5% level with MSS4/MSS6 and with MSS4/MSS7. Further investigation is required before ERTS imagery can be routinely used detecting and estimating disease severity and yield reduction.

  9. Distribution of buried hydrothermal alteration deduced from high-resolution magnetic surveys in Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Bouligand, Claire; Glen, Jonathan M. G.; Blakely, Richard J.

    2014-04-01

    Yellowstone National Park (YNP) displays numerous and extensive hydrothermal features. Although hydrothermal alteration in YNP has been extensively studied, the volume, geometry, and type of rock alteration at depth remain poorly constrained. In this study, we use high-resolution airborne and ground magnetic surveys and measurements of remanent and induced magnetization of field and drill core samples to provide constraints on the geometry of hydrothermal alteration within the subsurface of three thermal areas in YNP (Firehole River, Smoke Jumper Hot Springs, and Norris Geyser Basin). We observe that hydrothermal zones from both liquid- and vapor-dominated systems coincide with magnetic lows observed in aeromagnetic surveys and with a decrease of the amplitude of short-wavelength anomalies seen in ground magnetic surveys. This suggests a strong demagnetization of both the shallow and deep substratum within these areas associated with the removal of magnetic minerals by hydrothermal alteration processes. Such demagnetization is confirmed by measurements of rock samples from hydrothermal areas which display significantly decreased total magnetization. A pronounced negative anomaly is observed over the Lone Star Geyser and suggests a significant demagnetization of the substratum associated with areas displaying large-scale fluid flow. The ground and airborne magnetic surveys are used to evaluate the distribution of magnetization in the subsurface. This study shows that significant demagnetization occurs over a thickness of at least a few hundred meters in hydrothermal areas at YNP and that the maximum degree or maximum thickness of demagnetization correlates closely with the location of hydrothermal activity and mapped alteration.

  10. The age of the Veritas asteroid family deduced by chaotic chronology

    NASA Astrophysics Data System (ADS)

    Milani, Andrea; Farinella, Paolo

    1994-07-01

    ASTEROID families are groups of objects produced in disruptive collisions of a parent body. Although family members are widely dispersed in real space, they cluster in the parameter space defined by their so-called proper elements, and can thus be distinguished from the background asteroid population1-3. For most asteroids, these parameters are very close to being invariants of motion and families are still apparent billions of years after their formation4'5. But these parameters undergo chaotic diffusion, and in some cases the rate of diffusion might be large enough that a family member exits from the region of proper-element space occupied by the family after a characteristic time which is shorter than the lifetime of the Solar System. In this case, the characteristic time should provide an approximate upper bound to the age of the family. Here we use this 'chaotic chronology' method to estimate the lifetime of the unusually compact Veritas family. Calculations of the evolu-tion of the proper elements of the family show that two members (including the largest, 490 Veritas) wander outside the borders of the family on a timescale of about 50 Myr, indicating that the family has an age of less than this.

  11. Seismic slip direction deduced from the magnetic fabric of frictional melts

    NASA Astrophysics Data System (ADS)

    Ferre, E. C.

    2015-12-01

    The direction of seismic slip constitutes an important focal mechanism parameter particularly for ancient-prehistoric earthquakes. Here I show that in most cases, the magnetic fabric of fault pseudotachylytes indicates the direction of coseismic slip as a result of the dominant simple shear nature of frictional melt flow. The magnetic fabric arises from the shape or crystallographic preferred orientation of magnetically anisotropic minerals (paramagnetic silicates or ferromagnetic oxides) in a viscous medium. This fabric, acquired in a manner similar to that of other magmas, becomes rapidly frozen as the frictional melt is quenched. This kinematic information, coupled with fault plane orientation and generation vein thickness, provides new and critical insight for the earthquake focal mechanism. The magnetic fabric of pseudotachylytes, therefore, not only constitutes a valuable kinematic criterion for these fault rocks but also could expand our knowledge on prehistoric seismic events.

  12. A new paleointensity result deduced for the Oligocene period fromQatrani basalt, Egypt

    NASA Astrophysics Data System (ADS)

    Saleh, Ahmed; Yamamoto, Yuhji

    2016-04-01

    We have conducted paleodirection and paleointensity measurements of basalt flows from Qatrani basalt, Egypt. Published age of Qatrani basat is 25±2 Ma. Various rock magnetic analyses indicate that the main magnetic carriers of samples are one phase of pure magnetite (Ti-poor titanomagnetites), which have pseudo single domain (PSD) sizes. Directional analysis of the Oligocene basalts is very straightforward and updated mean VGPs have been calculated from the Qatrani (68N, 90E; Kappa=274; A95=1.8) which is coincide with the previous Oligocene paleomagnetic studies. The Tsunakawa-Shaw (LTD-DHT Shaw) method yielded five successful results of 12.9-17.5 μTfrom two sites, giving one acceptable site-mean paleointensityof 15.5 μT with a standard deviation of 1.8 μTat the 25±2Ma. In terms of a dipole moment, an average VDM is calculated to be 2.7×1022A m2with a standard deviation of 1.29×1022Am2. This is the first result from Egypt, and is associated with a reasonably high QPI value (Biggin and Paterson, 2015) of 5. The newly obtained VDM is indistinguishable from an average VDM of 3.55×1022Am2with a standard deviation of 0.67×1022Am2 calculated from theselected 65 site-mean Thellier paleointensity data from the latest paleointensity database, and is about third of the present geomagnetic dipole moment (˜8×1022 Am2).

  13. Education et Developpement. Une Approche aux Interventions d'Education en Milieux Defavorises. MEQ, Mars 1975.

    ERIC Educational Resources Information Center

    Centrale de L'Enseignement du Quebec (Canada).

    This document is a commentary on a report by the Quebec Ministry of Education on the problem of educating the disadvantaged. One basic criticism of the report is that it is not enough to decry the failure of the schools and propose a strategy of compensatory education to solve the problem of disadvantagement. It is necessary to realize that the…

  14. The mechanism of the acclimation of Nannochloropsis oceanica to freshwater deduced from its transcriptome profiles

    NASA Astrophysics Data System (ADS)

    Guo, Li; Yang, Guanpin

    2015-10-01

    In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with sea-water and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to freshwater. Differentially expressed genes were mainly assigned to the degradation of cell components, ion transportation, and ribosomal biogenesis. These findings indicate that the algal cells degrade its components (mainly amino acids and fatty acids) to yield excessive energy (ATP) to maintain cellular ion (mainly K+ and Ca2+) homeostasis, while the depletion of amino acids and ATP, and the reduction of ribosomes attenuate the protein translation and finally slow down the cell growth.

  15. Climate stability as deduced from an idealized coupled atmosphere-ocean model

    SciTech Connect

    Tang, B.; Weaver, A.J.

    1995-04-01

    The stability of an idealized climate system is investigated using a simple coupled atmosphere-ocean box model. Motivated by the results from general circulation models. the main physical constraint imposed on the system is that the net radiation at the top of the atmosphere is fixed. The specification of an invariant equatorial atmospheric temperature. Consistent with paleoclimatic data, allows the hydrological cycle to be internally determined from the poleward heat transport budget, resulting in a model that has a plausible representation of the hydrological cycle-thermohaline circulation interaction. The model suggests that the stability and variability of the climate system depends fundamentally on the mean climatic state (total heat content of the system). When the total heat content of the climate system is low, a stable present-day equilibrium exists with high-latitude sinking. Conversely, when the total heat content is high, a stable equatorial sinking equilibrium exists. For a range of intermediate values of the total heat content, internal climatic oscillations can occur through a hydrological cycle-thermohaline circulation feedback process. Experiments conducted with the model reveal that under a 100-year 2xCO{sub 2} warming, the thermohaline circulation first collapses but then recovers. Under a 100-year 4 x CO{sub 2} warming, the thermohaline circulation collapses and remains collapsed. Recent paleoclimatic data suggest that the climate system may behave very differently for warmer climate. Our results suggest that this may be attributed to the enhanced poleward freshwater transport, which causes increased instability of the present-day thermohaline circulation. 50 refs., 4 figs., 1 tab.

  16. Scaling law deduced from impact-cratering experiments on basalt targets

    NASA Astrophysics Data System (ADS)

    Takagi, Y.; Hasegawa, S.; Suzuki, A.

    2014-07-01

    Since impact-cratering phenomena on planetary bodies were the key process which modified the surface topography and formed regolith layers, many experiments on non-cohesive materials (sand, glass beads) were performed. On the other hand, experiments on natural rocks were limited. Especially, experiments on basalt targets are rare, although basalt is the most common rocky material on planetary surfaces. The reason may be the difficulties of obtaining basalt samples suitable for cratering experiments. Recently, we obtained homogenous and crackless large basalt blocks. We performed systematic cratering experiments using the basalt targets. Experimental Procedure: Impact experiments were performed using a double stage light-gas (hydrogen) gun on the JAXA Sagamihara campus. Spherical projectiles of nylon, aluminum, stainless steel, and tungsten carbide were launched at velocities between 2400 and 6100 m/sec. The projectiles were 1.0 to 7.1 mm in diameter and 0.004 to 0.22 g in mass. The incidence angle was fixed at 90 degrees. The targets were rectangular blocks of Ukrainian basalt. The impact plane was a square with 20-cm sides. The thickness was 9 cm. Samples were cut out from a columnar block so that the impact plane might become perpendicular to the axis of the columnar joint. The mass was about 10.5 kg. The density was 2920 ± 10 kg/m^3 . Twenty eight shots were performed. Three-dimensional shapes of craters were measured by an X-Y stage with a laser displacement sensor (Keyence LK-H150). The interval between the measurement points was 200 micrometer. The volume, depth, and aperture area of the crater were calculated from the 3-D data using analytical software. Since the shapes of the formed craters are markedly asymmetrical, the diameter of the circle whose area is equal to the aperture area was taken as the crater diameter. Results: The diameter, depth, and the volume of the formed craters are normalized by the π parameters. Experimental conditions are also expressed by the π parameters. The figure shows the relation of the normalized volume and the π_3 parameter. A clear dependency on the projectile density is shown in the figure. Multiple regression analyses yield the relation π_V ∝ π_3^{-1.04 ± 0.14} π_4^{0.45 ± 0.18} . Other results and comparisons with those of previous studies are presented in the paper.

  17. The Building of Continental Crust in the Archean Superior Province, Canada, Deduced from Heat Flow Data

    NASA Astrophysics Data System (ADS)

    Jaupart, C. P.; Mareschal, J.

    2013-12-01

    Making continental crust can be achieved in several different ways, including extraction of melts from a mantle plume or from a subducting slab. Cratonization, i.e. the formation of mature stable continental crust, requires two additional steps, horizontal accretion of a number of terranes and belts and vertical internal differentiation leading to separation of an enriched upper crust from a depleted lower crust. Heat flow and heat production data provide constraints on the bulk crustal composition as well as on the degree of internal differentiation, and hence bring key constraints on crust-building processes. Together with older data, new measurements from the Archean Superior Province, Canadian Shield, are used to document how and with what material this large piece of continental crust was built. The southern Superior Province was assembled out of an old nucleus made of gneisses and tonalite-granodiorite plutons called the North Caribou Super Terrane, and a number of belts and terranes that were sequentially docked to its southern margin. The North Caribou area was subjected to magmatic and metamorphic activity spanning about 1.1 Gy from 3.8 to 2.7 Gy. Alternating belts of metasedimentary and volcanic rocks on the one hand and greenstone and plutonic rocks on the other hand made the craton grow to about twice its initial size in ≈100 My. The average heat flow is much lower in the North Caribou core region than in the younger volcanic/plutonic belts (Wabigoon and Wawa-Abitibi) to the South, 30 versus 44 mW/m2. The heat flux is also slightly higher (48mW/m2) in the metasedimentary (English River and Quetico) than in the plutonic belts. The two volcanic/plutonic belts share the same characteristics, testifying to a remarquable uniformity of crust-building mechanisms on a large-scale. The marked difference between the older craton nucleus and the younger belts requires the operation of two very different processes. The very shape and geological structure of the belts indicate that they were island arcs and associated basins. The craton nucleus was formed in a different way, presumably by melting in a mantle upwelling. In addition, the craton nucleus has an enriched upper crust, in contrast to the younger belts that do not exhibit marked internal differentiation. Late, post-orogenic, magmatism that dots the whole southern Superior Province is probably due to internal heating of the crust by its own radioactive sources.

  18. Properties of rainfall in a tropical volcanic island deduced from UHF wind profiler measurements

    NASA Astrophysics Data System (ADS)

    Réchou, A.; Narayana Rao, T.; Bousquet, O.; Plu, M.; Decoupes, R.

    2014-02-01

    The microphysical properties of rainfall at the island of Réunion are analysed and quantified according to one year of wind profiler observations collected at Saint-Denis international airport. The statistical analysis clearly shows important differences in rain vertical profiles as a function of the seasons. During the dry season, the vertical structure of precipitation is driven by trade wind and boundary-layer inversions, both of which limit the vertical extension of the clouds. The rain rate is lower than 2.5 mm h-1 throughout the lower part of the troposphere (about 2 km) and decreases in the higher altitudes. During the moist season, the average rain rate is around 5 mm h-1 and nearly uniform from the ground up to 4 km. The dynamical and microphysical properties (including drop size distributions) of four distinct rainfall events are also investigated through the analysis of four case studies representative of the variety of rain events occurring on Réunion: summer deep convection, northerly-to-northeasterly flow atmospheric pattern, cold front and winter depression embedded in trade winds. Radar-derived rain parameters are in good agreement with those obtained from collocated rain gauge observations in all cases, which demonstrates that accurate qualitative and quantitative analysis can be inferred from wind profiler data. Fluxes of kinetic energy are also estimated from wind profiler observations in order to evaluate the impact of rainfall on soil erosion. Results show that horizontal kinetic energy fluxes are systematically one order of magnitude higher than vertical kinetic energy fluxes. A simple relationship between the reflectivity factor and vertical kinetic energy fluxes is proposed based on the results of the four case studies.

  19. Evaluating woody material transport and deposition in alpine rivers and deducing risk mitigation approaches

    NASA Astrophysics Data System (ADS)

    Mazzorana, B.; Zischg, A.; Hübl, J.; Largiader, A.

    2009-04-01

    The impact levels of recent flashflood events in Switzerland and Western Austria in 2005 have significantly been accentuated by a considerable amount of transported woody material. As a consequence, either protection measures or bridges suffered considerable damage. Furthermore, cross-sectional obstructions due to woody material entrapment caused unexpected floodplain inundations resulting in severe damage to elements at risk. Until now, these woody material transport phenomena are neither sufficiently taken into account nor systematically considered, leading to a decrease in prediction accuracy during the procedure of hazard mapping. To close this gap, a procedure is proposed that (1) allows for the estimation of woody material recruitment from wood covered bankslopes and floodplains within the perimeter of the considered extreme flood event; and (2) permits the analysis of, the disposition for woody material entrainment and transport to selected critical configurations along the channel. The proposed procedure had been implemented into an ArcGIS-environment and provided indications for potential accentuation of flood hazards due to the transport of woody material. Results from a case study suggested the general applicability of the concept. The computational results can be used to devise effective risk mitigation strategies that comprise: (1) selective woody material volume reduction within the source areas, (2) thinning measures to increase the elasticity of the forest structure, (3) preventive interception of transported woody material and (4) redesign of the critical configurations.

  20. The optical luminosity function of gamma-ray bursts deduced from ROTSE-III observations

    SciTech Connect

    Cui, X. H.; Wu, X. F.; Wei, J. J.; Yuan, F.; Zheng, W. K.; Liang, E. W.; Akerlof, C. W.; McKay, T. A.; Ashley, M. C. B.; Flewelling, H. A.; Göǧüş, E.; Güver, T.; Kızıloǧlu, Ü.; Pandey, S. B.; Rykoff, E. S.; Rujopakarn, W.; Schaefer, B. E.; Wheeler, J. C.; Yost, S. A. E-mail: xfwu@pmo.ac.cn E-mail: fang.yuan@anu.edu.au E-mail: lew@gxu.edu.cn

    2014-11-10

    We present the optical luminosity function (LF) of gamma-ray bursts (GRBs) estimated from a uniform sample of 58 GRBs from observations with the Robotic Optical Transient Search Experiment III (ROTSE-III). Our GRB sample is divided into two sub-samples: detected afterglows (18 GRBs) and those with upper limits (40 GRBs). We derive R-band fluxes for these two sub-samples 100 s after the onset of the burst. The optical LFs at 100 s are fitted by assuming that the co-moving GRB rate traces the star formation rate. While fitting the optical LFs using Monte Carlo simulations, we take into account the detection function of ROTSE-III. We find that the cumulative distribution of optical emission at 100 s is well described by an exponential rise and power-law decay, a broken power law,and Schechter LFs. A single power-law (SPL) LF, on the other hand, is ruled out with high confidence.

  1. Constructing a folding model for protein S6 guided by native fluctuations deduced from NMR structures

    SciTech Connect

    Lammert, Heiko; Noel, Jeffrey K.; Haglund, Ellinor; Onuchic, José N.; Schug, Alexander

    2015-12-28

    The diversity in a set of protein nuclear magnetic resonance (NMR) structures provides an estimate of native state fluctuations that can be used to refine and enrich structure-based protein models (SBMs). Dynamics are an essential part of a protein’s functional native state. The dynamics in the native state are controlled by the same funneled energy landscape that guides the entire folding process. SBMs apply the principle of minimal frustration, drawn from energy landscape theory, to construct a funneled folding landscape for a given protein using only information from the native structure. On an energy landscape smoothed by evolution towards minimal frustration, geometrical constraints, imposed by the native structure, control the folding mechanism and shape the native dynamics revealed by the model. Native-state fluctuations can alternatively be estimated directly from the diversity in the set of NMR structures for a protein. Based on this information, we identify a highly flexible loop in the ribosomal protein S6 and modify the contact map in a SBM to accommodate the inferred dynamics. By taking into account the probable native state dynamics, the experimental transition state is recovered in the model, and the correct order of folding events is restored. Our study highlights how the shared energy landscape connects folding and function by showing that a better description of the native basin improves the prediction of the folding mechanism.

  2. Shallow structure and recent evolution of the Aegean Sea deduced from the seismic reflection analysis

    SciTech Connect

    Laure, M.; Mascle, J.

    1988-08-01

    Together with the Tyrrhenian Sea, the Aegean Sea represents one of two marine basins still developing as a consequence of the subduction of the African lithosphere beneath Europe. Despite many geophysical similarities with the Tyrrhenian Sea, the Aegean displays a specific structural segmentation characterized by two distinct domains separated by the central Aegean. To the north of the basin, the so-called North Aegean trough likely represents the western marine extension of the transtensive Anatolian transform fault zone. The northern margin of this area contains a series of disconnected, often thickly sedimented small basins that probably initiated during the late Miocene as a consequence of a dominantly north-south extension; typical uppermost Miocene (Messinian) formations can be observed on seismic grounds. To the south, the Cretan Sea shows clear evidence of important distensive events occurring during two main episodes and following two main trends; a dominantly north-south-directed extension is responsibile for most of the structural features detected along both the Cretan and southern Cyclades margins.

  3. Constructing a folding model for protein S6 guided by native fluctuations deduced from NMR structures

    NASA Astrophysics Data System (ADS)

    Lammert, Heiko; Noel, Jeffrey K.; Haglund, Ellinor; Schug, Alexander; Onuchic, José N.

    2015-12-01

    The diversity in a set of protein nuclear magnetic resonance (NMR) structures provides an estimate of native state fluctuations that can be used to refine and enrich structure-based protein models (SBMs). Dynamics are an essential part of a protein's functional native state. The dynamics in the native state are controlled by the same funneled energy landscape that guides the entire folding process. SBMs apply the principle of minimal frustration, drawn from energy landscape theory, to construct a funneled folding landscape for a given protein using only information from the native structure. On an energy landscape smoothed by evolution towards minimal frustration, geometrical constraints, imposed by the native structure, control the folding mechanism and shape the native dynamics revealed by the model. Native-state fluctuations can alternatively be estimated directly from the diversity in the set of NMR structures for a protein. Based on this information, we identify a highly flexible loop in the ribosomal protein S6 and modify the contact map in a SBM to accommodate the inferred dynamics. By taking into account the probable native state dynamics, the experimental transition state is recovered in the model, and the correct order of folding events is restored. Our study highlights how the shared energy landscape connects folding and function by showing that a better description of the native basin improves the prediction of the folding mechanism.

  4. F region postsunset plasma structures at low latitudes deduced from the Swarm satellite constellation

    NASA Astrophysics Data System (ADS)

    Stolle, Claudia; Xiong, Chao; Kervalishvili, Guram; Lühr, Hermann; Rauberg, Jan; Michaelis, Ingo

    2016-04-01

    ESA's constellation mission Swarm was successfully launched on 22 November 2013. The three satellites are orbiting the Earth at 470 km and 520 km altitude. The spacecraft carry instruments to monitor the plasma density and magnetic eld magnitude and their variations with high quality. We will present results on low latitude F region post sunset plasma irregularities (EPIs). EPIs are characterised by severe plasma density gradients and distinct magnetic field variations and cause GPS signal detection degradations. Our results show rather small scale sizes of EPIs (>44 km) in the zonal direction as well as more fragmented irregularities in the southern hemisphere where the ambient magnetic field is lower than on the northern hemisphere. From the Swarm spacecraft constellation with a zonal separation of about 150 km, we conclude that larger zonal scale sizes of irregularities exist in the early evening hours (around 1900 LT) and that the irregularities break into smaller structures later in the evening. However, we also observe examples where only one satellite detects EPIs, while the others show undisturbed ionization. We will present also such an example, and compare these observations with detections of depletions on satellites from other missions. There exist a strong link to low-latitude space weather: the plasma irregularities give rise to severe disturbances of GPS navigational signals and these can also be monitored on board the Swarm satellites simultaneously with the plasma irregularities.

  5. Volcanic and glacial evolution of Chachani-Nocarane complex (Southern Peru) deduced from the geomorphologic map.

    NASA Astrophysics Data System (ADS)

    Alcalá, J.; Zamorano, J. J.; Palacios, D.

    2012-04-01

    The Chachani-Nocarane (16°11'S; 71°31'W; 6.057 m asl) is a large volcanic complex located in the western Central-Andean Cordillera, South of Peru. The date of the last eruption is not known and there are no registers of recent volcanic activity. The complex is shaped by glacial forms belonging to different phases, and periglacial forms (several generations of rock glaciers) which alternate with volcanic forms. The aim of this research is to establish the glacio-volcanic evolution of the volcanic complex Chachani-Nocarane. In order to do so, a detailed 1:20.000 scale geomorphological map was elaborated by integrating the following techniques: interpretation of the 1:35.000 scale aerial photographs (Instituto Geográfico Nacional de Perú, 1956) and the analysis of satellite images (Mrsid; NASA, 2000). Finally, the cartography was corrected though field work campaigns. Through the geomorphologic analysis of the landforms and their relative position, we have identified twelve phases, seven volcanic and five glacial phases. The most ancient volcanic phase is locate to the north area of the study area and correspond with Nocarane and Chingana volcanoes, alignment NW-SE. Above those ensemble the rest of the large delimited geomorphological units overlap. The most recent is located to the SW and consists of a complex series of domes, lava cones and voluminous lavas. Within the glacial phases, the most ancient one is related to the Last Glacial Maximum during the Pleistocene. Over this period, glaciers formed moraines from 3150 to 3600 m asl. The most recent glacier pulsation corresponds to the Little Ice Age (LIA). The moraines related to that event are the closest to the summits, located between 5.100 and 5.300 m asl, and they represent the last trace of glacial activity on the volcanic complex. Currently, this tropical mountain does not have glaciers. The only solid-state water reserves are found in the form of permafrost, as shown by various generations of rock glaciers placed in the upper part of the mountain, between 4.300 and 5.400 m asl in Nevado Nocarane and between 4.350 and 5.100 m asl in Nevado Chachani. Most of the delimited rock glaciers were formed under vertical walls where the supply of detritus material is significant. The generation of rock glaciers found at a higher altitude presents geomorphological indicators of current activity. Research funded by CGL2009-7343 project, Government of Spain.

  6. Strain patterns deduced from high-resolution airborne surveys in Namibia

    NASA Astrophysics Data System (ADS)

    Ledru, P.; Garoeb, H.; Kamati, T.; Wackerle, R.; Martelet, G.; Truffert, C.

    2003-04-01

    High-resolution aeromagnetic dataset have been acquired in the framework of a long-term programme that aims at a complete coverage of Namibia in 2008. More than half of the territory has been already flown with a 200m line spacing and 2500m tie lines, at a terrain clearance of 80 to 100 m. The contribution of the interpretation of these datasets to the definition of the strain pattern is presented. The first test zone concerns an orogenic zone, the southern zone of the Damara belt, south of Rehoboth. The different maps of the gradients of the magnetic field reduced to the pole have been used in order to define the regional strain pattern. Following up a limited field work that has characterized the geometry and kinematics of the main discontinuities, it has been shown that this zone is characterized by one single orogenic phase marked by a reverse crustal-scale shear zone system (with a down-dip stretching direction) to which regional-scale NE-SW folding is related. The anastomosed shear zone system is thus traced along more than 200 km. A provisional foliation trajectory map can be drawn, transecting the bedding in the hinges of the folds within sediments and underlined by a magnetite-rich veinlet network within the pre-tectonic granites. Moreover, this strain pattern has been extended under the superficial deposits that cover the eastern half of the studied area. Automatic structural analysis has been performed using Geosoft and ArcView/SynArc. Thus, source edge detection, search of ridges and curvature analysis provide qualitative analysis while the search of discontinuities along the horizontal gradients of the magnetic field using SynArc produces a very satisfactory statistical approach of the structural pattern. A second test zone illustrates an extensional tectonic context, i.e. the northern termination of the NNE-SSW Mesozoic aborted rift, developed synchronously with the opening of the Southern Atlantic ocean at the Jurassic-Cretaceous boundary. A dense dolerite dyke network, poorly outcropping in this zone, is revealed. Its mapping has been performed mainly by using the ridges of the first vertical derivative of the magnetic field reduced to the pole. Up to 4 generations of dykes are differentiated, the apparent chronology suggesting a change from an initial rift to a strike slip environment, characterized by a sinistral component along the main NNE-SSW tectonic line. The magnetic maps also reveal that the emplacement of the alkaline ring complexes postdates this dolerite dyke network.

  7. Rapid dewatering of the crust deduced from ages of mesothermal gold deposits

    USGS Publications Warehouse

    Goldfarb, R.J.; Snee, L.W.; Miller, L.D.; Newberry, R.J.

    1991-01-01

    The large-scale migration of fluids through the continental crust has been well documented, but there is no consensus regarding the timing of fluid migration relative to erogenic episodes, or rates of crustal dewatering1. Here we present 40Ar/39Ar dates for muscovites from quartz veins along a major shear zone in southeast Alaska, which show that the veins were emplaced in the early Eocene, during the late stages of orogenic deformation. Hydrothermal activity took place for only about 1 Myr and along a distance of at least 200 km. The fluids were generated by metamorphic reactions in subducted crust along the North American plate margin, and were apparently trapped in the crust by the low permeabilities accompanying a convergent tectonic regime until 56 Myr ago. The rapid dewatering event coincided with a change in plate motion at 56-55 Myr, which caused a shift from convergent to partly transcurrent tectonics. We suggest that this change in tectonic regime led to increased crustal permeabilities and hence the possibility of large-scale fluid migration.

  8. Phylogenetic relationships of the green alga Volvox carteri deduced from small-subunit ribosomal RNA comparisons.

    PubMed

    Rausch, H; Larsen, N; Schmitt, R

    1989-09-01

    The 1788-nucleotide sequence of the small-subunit ribosomal RNA (srRNA) coding region from the chlorophyte Volvox carteri was determined. The secondary structure bears features typical of the universal model of srRNA, including about 40 helices and a division into four domains. Phylogenetic relationships to 17 other eukaryotes, including two other chlorophytes, were explored by comparing srRNA sequences. Similarity values and the inspection of phylogenetic trees derived by distance matrix methods revealed a close relationship between V. carteri and Chlamydomonas reinhardtii. The results are consistent with the view that these Volvocales, and the third green alga, Nanochlorum eucaryotum, are more closely related to higher plants than to any other major eukaryotic group, but constitute a distinct lineage that has long been separated from the line leading to the higher plants. PMID:2506359

  9. Lead Abundance In The Martian Mantle Deduced From The Isotopic Data In Snc Meteorites

    NASA Astrophysics Data System (ADS)

    Dreibus, G.; Jagoutz, E.

    Isotopic data are a powerful tool for the study of planetary evolution. Assuming that the SNC meteorites are rocks from Mars their Sm-Nd-, Rb-Sr- and Pb-Pb-isotope systematics reveal the time scale for the chemical evolution of the Martian mantle. From the Rb -Sr isotopic systematic the existence of 3 isotopically distinct reservoirs on Mars was postulated, which remained isolated for a period of 4.3 +/- 0.2 Ga. The basaltic shergottites Shergotty, Zagami and Los Angeles have relatively high radiogenic Sr, which might come from a planetary crust. A second group, characterized by non radiogenic Sr, consists of the two mafic cumulates Nakhla and Chassigny, the olivine rich basaltic shergottites DaG 476, SaU 005, Dhofar 019and the basaltic shergottite QUE 94201, which may represent the depleted mantle. The depletion of this reservoir must have taken place during a very early process. as derived from the primitive Sr isotopes and the existence of Nd-142, the daughter product of the extinct Sm-146, found in Chassigny, the Nakhlites, SaU 005, and DaG476. A third group, with intermediate Sr isotopic composition, represented by the lherzolitic shergottites, could be derived from a primitive, unfractionated mantle. Our observed correlation of Sr-isotopes with Pb-isotopes in SNC's permits to estimate the Pb abundance for the Martian mantle. The Pb isotopes of all measured SNCs show a similar pattern as Sr isotopes. The initial Pb data of Los Angeles, Shergotty, and Zagami from the enriched crustal reservoir and of Nakhla and SaU 005 from the depleted mantle reservoir plot close to the 4.5 Ga Pb -Pb isochron.. We used this correlation to estimate the µ value (238U/204Pb) of 3.1 for the Martian mantle. This corresponds to 366 ppb Pb. Compared to the Earth with a µ = 8.8, Pb is enriched on Mars by at least a fact or of 2.5. The same enrichment was found for all other moderately volatile and volatile elements on Mars. From the high abundance of Pb in the sulfide phases of iron meteorites a chalcophile behavior of Pb was postulated. Contrary to the Earth the Martian core is sulfur rich. But, the more than 2 fold enrichment of Pb in the silicate phase of Mars compared to that of Earth might exclude its chalcophile behavior. Lead, with a condensation temperature from a solar gas lower than 600oK belongs to the group of volatile elements. Obviously, during planetary formation and evolution Pb behaves like a volatile and not like a chalcophile element.

  10. Gamow-Teller Transitions in Proton Rich Exotic pf-shell Nuclei Deduced from Mirror Transitions

    SciTech Connect

    Fujita, Y.; Adachi, T.; Fujita, H.; Blank, B.; Brentano, P. von; Zell, K. O.; Berg, G. P. A.; Fujita, K.; Hatanaka, K.; Nakanishi, K.; Shimizu, Y.; Tameshige, Y.; Tamii, A.; Yosoi, M.; Negret, A.; Popescu, L.; Rubio, B.; Shimbara, Y.

    2010-08-12

    The rp-process nucleosynthesis proceeds through nuclei near the proton drip-line, in which Gamow-Teller (GT) transitions starting from unstable pf-shell nuclei play important roles. In the {beta}-decay study of these nuclei, half-lives can be measured rather accurately. On the other hand, in the high-resolution ({sup 3}He, t) charge-exchange reactions on mirror nuclei, individual GT transitions can be studied up to high excitations. For the accurate study of the GT transition strengths in the A = 52, T = 2, system, we compare and combine the {beta}-decay study of the proton-rich nucleus {sup 52}Ni and the {sup 52}Cr({sup 3}He, t) measurement assuming the isospin symmetry of the T{sub z} = {+-}2{yields}{+-}1 transitions.

  11. Use of Nanostructure-Initiator Mass Spectrometry to Deduce Selectivity of Reaction in Glycoside Hydrolases.

    PubMed

    Deng, Kai; Takasuka, Taichi E; Bianchetti, Christopher M; Bergeman, Lai F; Adams, Paul D; Northen, Trent R; Fox, Brian G

    2015-01-01

    Chemically synthesized nanostructure-initiator mass spectrometry (NIMS) probes derivatized with tetrasaccharides were used to study the reactivity of representative Clostridium thermocellum β-glucosidase, endoglucanases, and cellobiohydrolase. Diagnostic patterns for reactions of these different classes of enzymes were observed. Results show sequential removal of glucose by the β-glucosidase and a progressive increase in specificity of reaction from endoglucanases to cellobiohydrolase. Time-dependent reactions of these polysaccharide-selective enzymes were modeled by numerical integration, which provides a quantitative basis to make functional distinctions among a continuum of naturally evolved catalytic properties. Consequently, our method, which combines automated protein translation with high-sensitivity and time-dependent detection of multiple products, provides a new approach to annotate glycoside hydrolase phylogenetic trees with functional measurements. PMID:26579511

  12. Light elements burning reaction rates at stellar temperatures as deduced by the Trojan Horse measurements

    NASA Astrophysics Data System (ADS)

    Lamia, L.; Spitaleri, C.; La Cognata, M.; Palmerini, S.; Puglia, S. M. R.; Sergi, M. L.

    2015-02-01

    Experimental nuclear astrophysics aims at determining the reaction rates for astrophysically relevant reactions at their Gamow energies. For charged-particle induced reactions, the access to these energies is usually hindered, in direct measurements, by the presence of the Coulomb barrier between the interacting particles or by electron screening effects, which make hard the determination of the bare-nucleus S(E)-factor of interest for astrophysical codes. The use of the Trojan Horse Method (THM) appears as one of the most suitable tools for investigating nuclear processes of interest for astrophysics. Here, in view of the recent TH measurements, the main destruction channels for deuterium (2H ), for the two lithium 6,7Li isotopes, for the 9Be and the one for the two boron 10,11B isotopes will be discussed.

  13. Thrust kinematics deduced by primary and secondary magnetizations in the Internal Sierras (Central Pyrenees, Spain)

    NASA Astrophysics Data System (ADS)

    Oliva, B.; Pueyo, E.

    2003-04-01

    The Central Southern Pyrenees are composed (from N to S) by the Axial Zone (made by several basement-involved nappes; (Gavarnie and Guarga), the Internal Sierras (IS) fold and thrust belt (Larra and Monte Perdido units), the Jaca piggyback basin (turbiditic and molassic) and the External Sierras. Several paleomagnetic studies have been carried out during the last decades in all units except for the IS. Different amounts of rotation were reported, usually from primary directions. This work shows paleomagnetic results derived from recent investigations in the IS. 78 sites were sampled in different thrust sheets in the Larra and Monte Perdido units. Sites were collected in Upper Cretaceous rocks; all of them were homogeneously distributed along the range strike. A N-S section through the Eocene turbiditic basin was also done (9 sites) to link our results to previous data. Stepwise thermal demagnetization every 25-50^oC was performed to unravel the NRM components. Magnetic mineralogy essays (IRM, IST and low temperature) confirm magnetite as the major magnetic carrier. Two paleomagnetic components can be distinguished; A) an intermediate direction unblocking from 350^o to 450^oC and B) a high temperature component (from 500^o -575^oC). The B component displays two polarities and a positive fold and reverse tests whereas the A component shows only reverse polarity and a pervasive negative fold test. The A component has been also found in the Eocene transect. Two major clues help to constrain the remagnetization age; on one hand the deformation age (Early-Middle Eocene in the Larra and Monte Perdido units) and, on the other hand, the age of the turbiditic rocks (Middle Eocene). Therefore the remagnetization process took place by the end of the IS thrust system configuration or in a later period. Since the rotation detected by the A and B components are similar, the rotation age can be constrained as younger than the remagnetization. All these deductions have important implications in the Pyrenean kinematics: Larra and Monte Perdido units did not undergo any significant rotation during their configuration. Therefore the cover rocks accommodated the rotation during the basement units stacking (Gavarnie and/or Guarga nappes).

  14. Tectonic implications deduced from drill cores in the Qaidam basin, NE Tibetan Plateau (Invited)

    NASA Astrophysics Data System (ADS)

    Appel, E.; Zhang, W.; Fang, X.; Song, C.; Setzer, F.; Herb, C.

    2013-12-01

    The Qaidam Basin is the largest intermontane basin of the NE Tibetan Plateau and an ideal place to study the paleoenvironmental evolution and erosion history related to tectonic activity and climate change. We studied two cores of lacustrine sediments drilled in the western basin within a distance of about 25 km, the 940 m deep SG-1 core in the Chahansilatu sub-depression and the 723 m deep SG-1b core in the Jianshan anticline. These cores comprise fine-grained lacustrine sediments and according to our magnetostratigraphic results span the ages of ~2.8-1.1 Ma (SG-1) and ~7.3-1.6 Ma (SG-1b). The proxy record reveals a long-term drying trend, and several proxy parameters can be matched with the marine oxygen isotope curve indicating a tie to global climate change. However, overlying trends and stepwise changes of average sediment accumulation rates (SAR) point towards an influence of tectonic processes. The results of average SARs of core SG-1b show three intervals with relatively higher values from the bottom (>7.3 Ma) to 6.0 Ma, between 5.2 and 4.2 Ma and between 3.6 and 2.6 Ma. These phases are in temporal agreement with the deposition of thick coarse-grained deposits in other parts of the Qaidam basin, the development of the en-echelon s-shaped structure of the basin, the separation of the western basin into shallow subbasins and the formation of a large synclinal trough in the eastern basin, and tectonic activities at the north-eastern plateau and other plateau regions. Growth strata are crucial to interpret the fold-and-thrust geometry, and the kinematics modeled by variations of the sedimentation rate and the uplift rate in the folding region. Several features indicate that the geometry of growth strata at our study site has developed by limb rotation with clear changes of growth strata dip and thicknesses on the forelimb, rather than by kink-band migration. Comparison of the SARs from SG-1 and SG-1b demonstrates that the development of the limb rotation was controlled by overlap before ~1.6 Ma. Rapid uplift is indicated after ~1.6 Ma caused the occurrence of offlap and the termination of deposition at the Jianshan anticline region. This all can be probably related to pulse tectonic uplift of the NE Tibetan Plateau and fault-propagation-folding in the Qaidam Basin.

  15. How historical seismicity in oceans can be deduced from sailors' testimonies and related to modern tectonics

    NASA Astrophysics Data System (ADS)

    Legrand, Denis; Rouland, Daniel; Cisternas, Armando; Streng, Daniel; Gir, Roopa; Souriau, Annie

    2016-04-01

    Before seismological catalogs were routinely produced, seafarers experienced major seismic events at sea that were documented in their logs. This article analyzes some of these old records - mostly from eighteenth and nineteenth centuries - in the context of plate tectonics. Large shocks that were felt on ships are related either to earthquakes, sub-marine volcanic eruptions, or to sub-marine sliding of rocks and/or sediments. We analyze various related parameters such as the location and size of the shaking, the duration of the shock, and the associated noise. A total of 396 observations have been retained for this study, mostly located in the Atlantic Ocean, reflecting its intense maritime traffic during the period of interest. Some of the detailed accounts allow us to clearly identify the nature of the shocks, including a possible interpretation in terms of focal mechanism. Our results, when compared to historical catalogs, reveal many previously undetected large events. Macroseismic results for a few large historical events occurring near the coasts confirm the validity of our approach, but also reveal its limitations. The good locations of most of the events allow us to relate them to plate boundaries. The Romanche transform zone has deserved particular interest due to the large number of related testimonies. This study particularly illustrates that historical seismicity may be applied to oceans. The collected testimonies also show how impressive and dangerous these large earthquakes at sea are, despite the absence of S-waves.

  16. Constructing a folding model for protein S6 guided by native fluctuations deduced from NMR structures.

    PubMed

    Lammert, Heiko; Noel, Jeffrey K; Haglund, Ellinor; Schug, Alexander; Onuchic, José N

    2015-12-28

    The diversity in a set of protein nuclear magnetic resonance (NMR) structures provides an estimate of native state fluctuations that can be used to refine and enrich structure-based protein models (SBMs). Dynamics are an essential part of a protein's functional native state. The dynamics in the native state are controlled by the same funneled energy landscape that guides the entire folding process. SBMs apply the principle of minimal frustration, drawn from energy landscape theory, to construct a funneled folding landscape for a given protein using only information from the native structure. On an energy landscape smoothed by evolution towards minimal frustration, geometrical constraints, imposed by the native structure, control the folding mechanism and shape the native dynamics revealed by the model. Native-state fluctuations can alternatively be estimated directly from the diversity in the set of NMR structures for a protein. Based on this information, we identify a highly flexible loop in the ribosomal protein S6 and modify the contact map in a SBM to accommodate the inferred dynamics. By taking into account the probable native state dynamics, the experimental transition state is recovered in the model, and the correct order of folding events is restored. Our study highlights how the shared energy landscape connects folding and function by showing that a better description of the native basin improves the prediction of the folding mechanism. PMID:26723626

  17. Mesonic effects in nuclei near sup 208 Pb deduced from. beta. decay

    SciTech Connect

    Warburton, E.K.

    1990-01-01

    The mesonic enhancement of the time-like component of the weak axial current in nuclear matter is very large and is best observed via its effect on the decay rate of {Delta}J = 0 ({pi}{sub i}{pi} {sub f} = {minus}) {beta} decay. Studies in the A = 16, 40, and 90 regions yield enhancements of 40--60% over the impulse approximation. The lead region is a rich source of information on these first-forbidden decays. This study is the first to extract information on mesonic enhancement from these decays. {sup 206}Hg {yields} {sup 206}Tl {yields} {sup 206}Pb is chosen to exemplify the approach which has been applied to 10 or so first-forbidden decays in A = 205--214 nuclei. The nuclear wave functions are evaluated via large-basis shell-model calculations. The results indicate a much larger enhancement than expected and thus the possibility of some non-nucleonic effect in addition to the mesonic enhancement considered to date.

  18. The structure of the magnetosphere as deduced from magnetospherically reflected whistlers

    NASA Technical Reports Server (NTRS)

    Edgar, B. C.

    1972-01-01

    Very low frequency (VLF) electromagnetic wave phenomenon called the magnetospherically reflected (MR) whistler was investigated. VLF (0.3 to 12.5 kHz) data obtained from the Orbiting Geophysical Observatories 1 and 3 from October 1964 to December 1966 were used. MR whistlers are produced by the dispersive propagation of energy from atmospheric lightning through the magnetosphere to the satellite along ray paths which undergo one or more reflections due to the presence of ions. The gross features of MR whistler frequency-time spectrograms are explained in terms of propagation through a magnetosphere composed of thermal ions and electrons and having small density gradients across L-shells. Irregularities observed in MR spectra were interpreted in terms of propagation through field-aligned density structures. Trough and enhancement density structures were found to produce unique and easily recognizable signatures in MR spectra. Sharp cross-field density dropoff produces extra traces in MR spectrograms.

  19. Outbreaks of Yuzu Dieback in Goheung Area: Possible Causes Deduced from Weather Extremes.

    PubMed

    Kim, Kwang-Hyung; Kim, Gyoung Hee; Son, Kyeong In; Koh, Young Jin

    2015-09-01

    Starting in 2012, severe diebacks usually accompanied by abundant gum exudation have occurred on yuzu trees in Goheung-gun, Jeonnam Province, where severely affected trees were occasionally killed. On-farm surveys were conducted at 30 randomly-selected orchards located at Pungyang-myeon, Goheung-gun, and the resulting disease incidences were 18.5% and 39.6% for dieback and gumming symptoms, respectively. Black spots on branches and leaves also appeared on infected trees showing a typical dieback symptom. Morphological and molecular identifications of the isolated fungal organisms from lesions on the symptomatic leaves and branches revealed that they are identical to Phomopsis citri, known to cause gummosis. In order to find the reason for this sudden epidemic, we investigated the weather conditions that are exclusively distinct from previous years, hypothesizing that certain weather extremes might have caused the severe induction of pre-existing disease for yuzu. There were two extreme temperature drops beyond the yuzu's cold hardiness limit right after an abnormally-warm-temperature-rise during the winter of 2011-12, which could cause severe frost damage resulting in mechanical injuries and physiological weakness to the affected trees. Furthermore, there was an increased frequency of strong wind events, seven times in 2012 compared to only a few times in the previous years, that could also lead to extensive injuries on branches. In conclusion, we estimated that the possible damages by severe frost and frequent strong wind events during 2012 could cause the yuzu trees to be vulnerable to subsequent fungal infection by providing physical entries and increasing plant susceptibility to infections. PMID:26361477

  20. Thermodynamic regulation of ocean warming by cirrus clouds deduced from observations of the 1987 El Nino

    NASA Technical Reports Server (NTRS)

    Ramanathan, V.; Collins, W.

    1991-01-01

    Observations made during the 1987 El Nino show that in the upper range of sea surface temperatures, the greenhouse effect increases with surface temperature at a rate which exceeds the rate at which radiation is being emitted from the surface. In response to this 'super greenhouse effect', highly reflective cirrus clouds are produced which act like a thermostat, shielding the ocean from solar radiation. The regulatory effect of these cirrus clouds may limit sea surface temperatures to less than 305 K.

  1. Millennial-scale hard rock erosion rates deduced from luminescence-depth profiles

    NASA Astrophysics Data System (ADS)

    Sohbati, R.; Liu, J.; Murray, A. S.; Jain, M.; Pederson, J. L.; Guralnik, B.; Egholm, D. L.; Gupta, S.

    2015-12-01

    Optically stimulated luminescence (OSL) is a well-established Quaternary dating method that is conventionally used to determine the time when sedimentary grains were last exposed to daylight. Recently, a very different approach to this concept has helped develop a new technique to estimate the length of time a rock surface was exposed to daylight. When a rock surface is first exposed to daylight the charge population (and so the latent luminescence signal) trapped in its constituent minerals (e.g. quartz and feldspar) starts to decrease. This charge had accumulated due to previous exposure to natural ionizing radiation. As the surface is exposed to light for longer periods, the latent luminescence signal is reduced farther into the rock. In a rock surface which has been exposed to light for a prolonged period (decades to millennia), the remaining luminescence will be zero (fully bleached) at the surface and then increase, initially exponentially, before approaching saturation at a depth where charge detrapping due to light penetration is negligible compared to the rate of charge trapping due to the environmental dose rate. By modelling the characteristic shape of luminescence resetting with depth into rock surfaces, Sohbati et al. (2012) proposed a new surface-exposure dating technique based on OSL. Here we further develop the current model to include the effect of erosion rate on luminescence-depth profiles. By fitting the model to local known-age calibration samples, we first determine the site-specific resetting rates of the luminescence signal at rock surfaces. We then use the calibration values in a numerical model to derive the steady-state erosion rate for rocks of different mineralogy and different geological settings. The preliminary erosion rates obtained from glacial and landslide granite boulders from the Chinese Pamir Plateau are ~1 mm.ka-1, whereas active streambeds of Permian sandstone in the Grabens district of Canyonlands National Park, Utah, are eroding at rates of >10 mm.ka-1, consistent with the existing denudation rates derived from cosmogenic nuclides.

  2. Use of pharmacologic antagonists to deduce commonalities of biologic activity among clostridial neurotoxins.

    PubMed

    Simpson, L L

    1988-06-01

    The pharmacologic activity of several clostridial neurotoxins was assayed on the mouse phrenic nerve-hemidiaphragm preparation. The substances that were assayed included botulinum neurotoxin types A, B, C and E and tetanus toxin. Experiments were done in the presence or absence of antagonists that inhibit either the internalization of toxins or intracellular expression of toxicity. Ammonium chloride and methylamine hydrochloride, agents that inhibit toxins that enter cells by receptor-mediated endocytosis, antagonized botulinum and tetanus neurotoxins. The magnitude of antagonism was substantial for all toxins. Calcium, 3,4-diaminopyridine and guanidine, agents that alter the intracellular expression of toxicity, produced a variable result. They were effective antagonists of botulinum neurotoxin type A, but they were less effective or inactive against the other neurotoxins. The ability of 3,4-diaminopyridine and guanidine to antagonize botulinum neurotoxin type A was highly calcium dependent. When ambient levels of the cation were reduced from 1.8 to 1.0 mM, the activity of the drugs was substantially reduced. The ability of these drugs to produce antagonism was also time dependent. When added simultaneously with toxin, they were maximally active; when added at later times, activity was diminished. A host of agents that alter intracellular levels of cyclic AMP, including theophylline, forskolin, isobutylmethylxanthine and cholera toxin, were evaluated as potential neurotoxin antagonists. Theophylline and isobutylmethylxanthine produced a transient increase in nerve-evoked muscle twitch. None of the drugs that alter tissue levels of cyclic AMP had a universal effect in antagonizing clostridial toxins. The data here have been compared with published data on drugs that antagonize binding of botulinum toxin and tetanus toxin.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2455038

  3. Jupiter's atmospheric composition and cloud structure deduced from absorption bands in reflected sunlight

    NASA Technical Reports Server (NTRS)

    Sato, M.; Hansen, J. E.

    1979-01-01

    The spectrum of sunlight reflected by Jupiter is analyzed by comparing observations of Woodman (1979) with multiple-scattering computations. The analysis yields information on the vertical cloud structure at several latitudes and on the abundance of CH4 and NH3 in the atmosphere of Jupiter. The abundances of CH4 and NH3 suggest that all ices and rocks are overabundant on Jupiter by a factor of 2 or more, providing an important constraint on models for the formation of Jupiter from the primitive solar nebula. The pressure level of the clouds, the gaseous NH3 abundance, the mean temperature profile, and the Clausius-Clapeyron relation suggest that these clouds are predominantly ammonia crystals with the cloud bottom at 600-700 mb. A diffuse distribution of aerosols exists between 150 and 500 mb, and the spectral variation of albedo reflects a changing bulk absorption coefficient of the material composing the aerosols and is diagnostic of the aerosol composition.

  4. Cenozoic marine geochemistry of thallium deduced from isotopic studies of ferromanganese crusts and pelagic sediments

    USGS Publications Warehouse

    Rehkamper, M.; Frank, M.; Hein, J.R.; Halliday, A.

    2004-01-01

    Cenozoic records of Tl isotope compositions recorded by ferromanganese (Fe-Mn) crusts have been obtained. Such records are of interest because recent growth surfaces of Fe-Mn crusts display a nearly constant Tl isotope fractionation relative to seawater. The time-series data are complemented by results for bulk samples and leachates of various marine sediments. Oxic pelagic sediments and anoxic marine deposits can be distinguished by their Tl isotope compositions. Both pelagic clays and biogenic oozes are typically characterized by ??205Tl greater than +2.5, whereas anoxic sediments have ??205Tl of less than -1.5 (??205Tl is the deviation of the 205Tl/203Tl isotope ratio of a sample from NIST SRM 997 Tl in parts per 104). Leaching experiments indicate that the high ??205Tl values of oxic sediments probably reflect authigenic Fe-Mn oxyhydroxides. Time-resolved Tl isotope compositions were obtained from six Fe-Mn crusts from the Atlantic, Indian, and Pacific oceans and a number of observations indicate that these records were not biased by diagenetic alteration. Over the last 25 Myr, the data do not show isotopic variations that significantly exceed the range of Tl isotope compositions observed for surface layers of Fe-Mn crusts distributed globally (??205 Tl=+12.8??1.2). This indicates that variations in deep-ocean temperature were not recorded by Tl isotopes. The results most likely reflect a constant Tl isotope composition for seawater. The growth layers of three Fe-Mn crusts that are older than 25 Ma show a systematic increase of ??205Tl with decreasing age, from about +6 at 60-50 Ma to about +12 at 25 Ma. These trends are thought to be due to variations in the Tl isotope composition of seawater, which requires that the oceans of the early Cenozoic either had smaller output fluxes or received larger input fluxes of Tl with low ??205Tl. Larger inputs of isotopically light Tl may have been supplied by benthic fluxes from reducing sediments, rivers, and/or volcanic emanations. Alternatively, the Tl isotope trends may reflect the increasing importance of Tl fluxes to altered ocean crust through time. ?? 2004 Elsevier B.V. All rights reserved.

  5. Three-dimensional morphology of equatorial plasma bubbles deduced from measurements onboard CHAMP

    NASA Astrophysics Data System (ADS)

    Park, J.; Lühr, H.; Noja, M.

    2015-01-01

    Total electron content (TEC) between Low-Earth-Orbit (LEO) satellites and the Global Navigation Satellite System (GNSS) satellites can be used to constrain the three-dimensional morphology of equatorial plasma bubbles (EPBs). In this study we investigate TEC measured onboard the Challenging Minisatellite Payload (CHAMP) from 2001 to 2005. We only use TEC data obtained when CHAMP passed through EPBs: that is, when in situ plasma density measurements at CHAMP altitude also show EPB signatures. The observed TEC gradient along the CHAMP track is strongest when the corresponding GNSS satellite is located equatorward and westward of CHAMP with elevation angles of about 40-60°. These elevation and azimuth angles are in agreement with the angles expected from the morphology of the plasma depletion shell proposed by Kil et al.(2009).

  6. Proxy late Holocene climatic record deduced from northwest Alaska beach ridges

    SciTech Connect

    Mason, O.K.; Jordan, J.W.

    1992-03-01

    A climatically sensitive, oscillatory pattern of progradation and erosion is revealed in late Holocene accretionary sand ridge and barrier island complexes of Seward Peninsula, northwest Alaska. Archaeological and geological radiocarbon dates constrain the chronology for the Cape Espenberg beach ridge plain and the Shishmaref barrier islands, 50 km to the southwest. Cape Espenberg, the depositional sink for the northeastward longshore transport system, contains the oldest sedimentary deposits: 3700 +/- 90 B.P. (B-23170) old grass from a paleosol in a low dune. The oldest date on the Shishmaref barrier islands is 1550 +/- 70 B.P. (B-23183) and implies that the modern barrier is a comparatively recent phenomenon. Late Holocene sedimentation along the Seward Peninsula varied between intervals of rapid progradation and erosion. Rapid progradation predominated from 4000-3300 B.P. and from 2000-1200 B.P., with the generation of low beach ridges without dunes, separated by wide swales. During erosional periods higher dunes built atop beach ridges: as between 3300-2000 B.P. and intermittently from 1000 B.P. to the present. Dune formation correlates with the Neoglacial and Little Ice Age glacial advances and increased alluviation in northern and central Alaska, while rapid progradation is contemporaneous with warmer intervals of soil and/or, peat formation atop alluvial terraces, dated to 4000-3500 and 2000-1000 B.P.

  7. Requirements for a marine geoid compatible with geoid deducible from satellite altimetry

    NASA Technical Reports Server (NTRS)

    Fubara, D. M. J.; Mourad, A. G.

    1972-01-01

    Theory deficiencies, data, and potential computational procedures that make the physical determination of the ocean geoid with true scale, shape, and absolute orientation of an elusive target are outlined. Satellite altimetry potential, in combination with adequate ground support and sea truth to resolve accurate global marine geoid and other peripheral benefits associated with ocean physics, are stated. Results are given in tabular form.

  8. On the turnaround of stratospheric ozone trends deduced from the reevaluated Umkehr record of Arosa, Switzerland

    NASA Astrophysics Data System (ADS)

    Zanis, P.; Maillard, E.; Staehelin, J.; Zerefos, C.; Kosmidis, E.; Tourpali, K.; Wohltmann, I.

    2006-11-01

    In this work, we investigate the issue of the turnaround in ozone trends of the recently homogenized Umkehr ozone record of Arosa, Switzerland, which is the longest Umkehr data set, extending from 1956 to date, using different statistical methods. All methods show statistically significant negative ozone trends from 1970 to 1995 in the upper stratosphere (above 32.6 km) throughout the course of the year as well as in the lower stratosphere (below 23.5 km) mainly during winter to spring, which can be partially attributed to dynamical changes. Over the recent period (1996-2004) the year-round trends in the lower stratosphere become positive and are more positive during the winter to spring period. The results also show changes in upper stratospheric ozone trends after 1996, which are, however, not statistically significant at 95% if aerosol correction is applied on the retrieved data. This lack of significant trend changes during the recent period in the upper stratosphere is regionally coherent with recent results derived from upper stratospheric ozone data recorded by lidars, microwave radiometers, and satellite instruments at an adjacent location. Although the positive change in trends after 1996 both for upper and lower stratospheric ozone is in line with the reduction of the emissions of ozone-depleting substances from the successful implementation of the Montreal Protocol and its amendments, we recommend, because of lack of significance for the upper stratospheric trends, repeating this analysis in a few years in order to overcome ambiguous results for documentation of the turnaround of upper stratospheric ozone.

  9. Structural and temporal requirements for geomagnetic field reversal deduced from lava flows.

    PubMed

    Singer, Brad S; Hoffman, Kenneth A; Coe, Robert S; Brown, Laurie L; Jicha, Brian R; Pringle, Malcolm S; Chauvin, Annick

    2005-03-31

    Reversals of the Earth's magnetic field reflect changes in the geodynamo--flow within the outer core--that generates the field. Constraining core processes or mantle properties that induce or modulate reversals requires knowing the timing and morphology of field changes that precede and accompany these reversals. But the short duration of transitional field states and fragmentary nature of even the best palaeomagnetic records make it difficult to provide a timeline for the reversal process. 40Ar/39Ar dating of lavas on Tahiti, long thought to record the primary part of the most recent 'Matuyama-Brunhes' reversal, gives an age of 795 +/- 7 kyr, indistinguishable from that of lavas in Chile and La Palma that record a transition in the Earth's magnetic field, but older than the accepted age for the reversal. Only the 'transitional' lavas on Maui and one from La Palma (dated at 776 +/- 2 kyr), agree with the astronomical age for the reversal. Here we propose that the older lavas record the onset of a geodynamo process, which only on occasion would result in polarity change. This initial instability, associated with the first of two decreases in field intensity, began approximately 18 kyr before the actual polarity switch. These data support the claim that complete reversals require a significant period for magnetic flux to escape from the solid inner core and sufficiently weaken its stabilizing effect. PMID:15800621

  10. An Empirical Model of Coronal Heating Deduced from SOHO Observations of Transition Region Dynamics

    NASA Technical Reports Server (NTRS)

    Emslie, A. Gordon

    2002-01-01

    The research carried out under the above award was concerned with the analysis of "explosive events" in the solar atmosphere. Explosive events are small energy releases that reveal themselves as skewed, broadened line profiles in the 10(exp 5) K degree material of the solar transition region. Using a data set of such events from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument on the NASA SoHo satellite, with unprecedented temporal, spatial and spectral resolution, we have evaluated (Winebarger, Emslie, Mariska, & Warren 1999, Ap. J., 526, 471) the energetics of these events through application of the Velocity Differential Emission Measure (VDEM) analysis technique introduced by Newton, Emslie & Mariska, (1995, Ap. J, 447, 915). This work has allowed us to evaluate the contribution of various terms (such as enthalpy flux, free-streaming of high-energy electrons, etc.) to the energy budget of these events.

  11. Stoichiometry of lipid interactions with transmembrane proteins--Deduced from the 3D structures.

    PubMed

    Páli, Tibor; Bashtovyy, Denys; Marsh, Derek

    2006-05-01

    The stoichiometry of the first shell of lipids interacting with a transmembrane protein is defined operationally by the population of spin-labeled lipid chains whose motion is restricted directly by the protein. Interaction stoichiometries have been determined experimentally for a wide range of alpha-helical integral membrane proteins by using spin-label ESR spectroscopy. Here, we determine the spatially defined number of first-shell lipids at the hydrophobic perimeter of integral membrane proteins whose 3D structure has been determined by X-ray crystallography and lipid-protein interactions characterized by spin-labeling. Molecular modeling is used to build a single shell of lipids surrounding transmembrane structures derived from the PDB. Constrained energy optimization of the protein-lipid assemblies is performed by molecular mechanics. For relatively small proteins (up to 7-12 transmembrane helices), the geometrical first shell corresponds to that defined experimentally by perturbation of the lipid-chain dynamics. For larger, multi-subunit alpha-helical proteins, the lipids perturbed directly by the protein may either exceed or be less in number than those that can be accommodated at the intramembranous perimeter. In these latter cases, the motionally restricted spin-labeled lipids can be augmented by intercalation, or can correspond to a specific subpopulation at the protein interface, respectively. For monomeric beta-barrel proteins, the geometrical lipid stoichiometry corresponds to that determined from lipid mobility for a 22-stranded barrel, but fewer lipids are motionally restricted than can be accommodated around an eight-stranded barrel. Deviations from the geometrical first shell, in the beta-barrel case, are for the smaller protein with a highly curved barrel. PMID:16641489

  12. Temperature and density dependence of properties of nuclear matter deduced from heavy ion collisions

    SciTech Connect

    Shlomo, Shalom

    2010-11-24

    Heavy-ion collision experiments are often employed to determine properties of nuclear matter under extreme conditions of temperature and density. This has been the subject of many investigations in recent decades, since understanding the equation of state of hot nuclear matter is very important in the study supernovae, neutron stars and nuclei. We present a short and limited review of the theoretical and experimental status of determining the temperature and density of the disassembling hot nucleus from ratios of the yields of emitted fragments.

  13. Seasonal and global cloud variations deduced from polar orbiting satellite radiance measurements

    NASA Technical Reports Server (NTRS)

    Rossow, W. B.; Kinsella, E.; Garder, L.

    1983-01-01

    The utility of currently available satellite radiance data for determining cloud radiative effects is evaluated. Each location observed by satellite is classified as clear or cloudy by comparison of measured radiances with specified values. Clear scene radiances are functions of time and location which represent the actual variation of the surface and atmospheric properties that affect the measured radiances. Cloud properties are determined by comparison of model and observed radiance. The seasonal change in cloud properties is shown, displaying the difference between July and January monthly mean values of cloud cover fraction, cloud top temperature, cloud top altitude, and cloud optical thickness.

  14. Origin of the human L1 elements: proposed progenitor genes deduced from a consensus DNA sequence.

    PubMed

    Scott, A F; Schmeckpeper, B J; Abdelrazik, M; Comey, C T; O'Hara, B; Rossiter, J P; Cooley, T; Heath, P; Smith, K D; Margolet, L

    1987-10-01

    A consensus sequence for the human long interspersed repeated DNA element, L1Hs (LINE or KpnI sequence), is presented. The sequence contains two open reading frames (ORFs) which are homologous to ORFs in corresponding regions of L1 elements in other species. The L1Hs ORFs are separated by a small evolutionarily nonconserved region. The 5' end of the consensus contains frequent terminators in all three reading frames and has a relatively high GC content with numerous stretches of weak homology with AluI repeats. The 5' ORF extends for a minimum of 723 bp (241 codons). The 3' ORF is 3843 bp (1281 codons) and predicts a protein of 149 kD which has regions of weak homology to the polymerase domain of various reverse transcriptases. The 3' end of the consensus has a 208-bp nonconserved region followed by an adenine-rich end. The organization of the L1Hs consensus sequence resembles the structure of eukaryotic mRNAs except for the noncoding region between ORFs. However, due to base substitutions or truncation most elements appear incapable of producing mRNA that can be translated. Our observation that individual elements cluster into subfamilies on the basis of the presence or absence of blocks of sequence, or by the linkage of alternative bases at multiple positions, suggests that most L1 sequences were derived from a small number of structural genes. An estimate of the mammalian L1 substitution rate was derived and used to predict the age of individual human elements. From this it follows that the majority of human L1 sequences have been generated within the last 30 million years. The human elements studied here differ from each other, yet overall the L1Hs sequences demonstrate a pattern of species-specificity when compared to the L1 families of other mammals. Possible mechanisms that may account for the origin and evolution of the L1 family are discussed. These include pseudogene formation (retroposition), transposition, gene conversion, and RNA recombination. PMID:3692483

  15. Mining a sea of data: deducing the environmental controls of ocean chlorophyll.

    PubMed

    Irwin, Andrew J; Finkel, Zoe V

    2008-01-01

    Chlorophyll biomass in the surface ocean is regulated by a complex interaction of physiological, oceanographic, and ecological factors and in turn regulates the rates of primary production and export of organic carbon to the deep ocean. Mechanistic models of phytoplankton responses to climate change require the parameterization of many processes of which we have limited knowledge. We develop a statistical approach to estimate the response of remote-sensed ocean chlorophyll to a variety of physical and chemical variables. Irradiance over the mixed layer depth, surface nitrate, sea-surface temperature, and latitude and longitude together can predict 83% of the variation in log chlorophyll in the North Atlantic. Light and nitrate regulate biomass through an empirically determined minimum function explaining nearly 50% of the variation in log chlorophyll by themselves and confirming that either light or macronutrients are often limiting and that much of the variation in chlorophyll concentration is determined by bottom-up mechanisms. Assuming the dynamics of the future ocean are governed by the same processes at work today, we should be able to apply these response functions to future climate change scenarios, with changes in temperature, nutrient distributions, irradiance, and ocean physics. PMID:19043583

  16. Grain Properties of Comet C/1995 O1 (Hale-Bopp) Deduced Through Computational Techniques

    NASA Technical Reports Server (NTRS)

    Harker, David E.; Wooden, Diane H.; Woodward, Charles E.; Lisse, Carey M.

    2001-01-01

    We present the computational analysis of the 7.6 - 13.2 micrometer infrared (IR) spectrophotometry (R approximately equal to 120) of comet C/1995 O1 (Hale-Bopp) in conjunction with concurrent observations which extend the spectral energy distribution from the near-infrared to far-infrared wavelengths. The observations include temporal epochs pre-perihelion, (1996 October UT and 1997 February UT), near perihelion (1997 April UT), and postperihelion (1997 June UT). Through the computational modeling of small amorphous carbon, and crystalline and amorphous silicate grains in Hale-Bopp's coma, we find that as the comet approached perihelion, the grain size distribution (the Hanner modified power law) steepened (N = 3.4 pre-perihelion, to N = 3.7 near and post-perihelion) along with an increase in the fractal porosity of larger (greater than 1 micrometer) grains. The peak of the grain size distribution remained constant (ap = 0.2 micrometer) at each epoch. We attribute the emergence of the 9.3 micrometer peak near perihelion to crystalline orthopyroxeno grains released from inside the nucleus. Crystalline silicates (olivine and orthopyroxene) make up about 30% (by mass) of the submicron sized (less than 1 micrometer) dust grains in Hale-Bopp's coma during each epoch.

  17. Two sulphur isotope provinces deduced from ores in the Mount Isa Eastern Succession, Australia

    NASA Astrophysics Data System (ADS)

    Davidson, G. J.; Dixon, G. H.

    1992-01-01

    The sulphur isotopic characteristics of ore deposits in the Australian Mount Isa Eastern Succession are not well known, unlike those of the Western Succession. In this study new detailed analyses are provided for recently discovered Eastern Succession mineralisation, such as the Starra and Osborne BIF-hosted Cu-Au ores, the Dugald River sediment-hosted Pb-Zn prospect, and four vein-hosted Cloncurry-style Cu±Au deposits (Hampden, Mt Elliot/Swan, Mt Cobalt, and the Answer Mine). All of the deposits of the Eastern Succession have δ34Ssulphide between -8 and +9%., regardless of their genesis. Empirically a moderate (δ34S range averaging close to 0%. characterises Starra-style Cu-Au and Pegmont Pb-Zn BIF ores, whereas shear and vein-style Cu mineralisation populations are tighter and do not average close to 0%. This is a particularly surprising result for Dugald River, where a larger isotopic variation more typical of stratiform sediment-hosted Pb-Zn ores in the region might have been expected. By comparison, Western Succession stratiform Pb-Zn and vein-style Cu deposits span a huge range of-15 to 51%. Large sulphur isotope ranges typify sulphate evaporite or organic sulphur-rich sedimentary successions. The lack of such variation in the Eastern Succession in turn suggests that primary evaporite sequences there were halite-dominated but sulphate-poor, and/or contained only limited volumes of organic-sulphur-rich sediment. Eastern Succession sequences were therefore less likely hosts for giant stratiform Pb-Zn deposits, because of their paucity of sulphur, although local sulphur sources permitted small deposits such as Dugald River to develop. Sedimentary conditions were more favourable for the development of sulphur-poor synsedimentary hydrothermal systems such as Starra, Osborne, and Pegmont, although sulphur isotope evidence is equivocal about the origin of these. Epigenetic deposits close to the Williams Batholith (Mt Dore, Hampden) owe their clustering around 0%. to their granitic fluid source.

  18. The verification of lightning location accuracy in Finland deduced from lightning strikes to trees

    NASA Astrophysics Data System (ADS)

    Mäkelä, Antti; Mäkelä, Jakke; Haapalainen, Jussi; Porjo, Niko

    2016-05-01

    We present a new method to determine the ground truth and accuracy of lightning location systems (LLS), using natural lightning strikes to trees. Observations of strikes to trees are being collected with a Web-based survey tool at the Finnish Meteorological Institute. Since the Finnish thunderstorms tend to have on average a low flash rate, it is often possible to identify from the LLS data unambiguously the stroke that caused damage to a given tree. The coordinates of the tree are then the ground truth for that stroke. The technique has clear advantages over other methods used to determine the ground truth. Instrumented towers and rocket launches measure upward-propagating lightning. Video and audio records, even with triangulation, are rarely capable of high accuracy. We present data for 36 quality-controlled tree strikes in the years 2007-2008. We show that the average inaccuracy of the lightning location network for that period was 600 m. In addition, we show that the 50% confidence ellipse calculated by the lightning location network and used operationally for describing the location accuracy is physically meaningful: half of all the strikes were located within the uncertainty ellipse of the nearest recorded stroke. Using tree strike data thus allows not only the accuracy of the LLS to be estimated but also the reliability of the uncertainty ellipse. To our knowledge, this method has not been attempted before for natural lightning.

  19. Aromatic hydrocarbon emissions in the United States deduced from tall tower measurements

    NASA Astrophysics Data System (ADS)

    Hu, L.; Millet, D. B.; Griffis, T. J.; Tessum, C.; Travis, K.

    2013-12-01

    Aromatic compounds including benzene (C6H6), toluene (C7H8), and xylenes (C8H10) are important anthropogenic precursors of secondary organic aerosol and ground-level ozone. In addition, benzene has been classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). However, their emissions remain poorly constrained. Here we present a full year (2011) of continuous aromatic hydrocarbon measurements by PTR-MS at the University of Minnesota tall tower Tracer Gas Observatory (KCMP tall tower, 244 m a.g.l, 44.689°N, 93.073°W). We interpret the tall tower data with a 0.5° ×0.667° GEOS-Chem nested grid simulation to constrain US sources of benzene, toluene, and xylenes. The tall tower observations reveal a clear high bias in the model, with model: measurement slopes of 1.8, 5.3, and 2.9 for benzene, toluene, and xylenes, respectively. The high bias reflects an overestimate of aromatic hydrocarbon emissions in the model, which are based on the RETRO emission Inventory. In this work, we employ a Bayesian inversion to interpret the KCMP tall tower measurements in terms of quantitative constraints on US aromatic sources and the importance of sectors such as on-road transportation, waste treatment and disposal, solvent use, etc. We discuss our findings relative to other emission estimates (e.g., the EPA NEI) and in terms of their implications for air quality modeling.

  20. Lower mantle thermal structure deduced from seismic tomography, mineral physics and numerical modelling

    NASA Technical Reports Server (NTRS)

    Cadek, O.; Yuen, D. A.; Steinbach, V.; Chopelas, A.; Matyska, C.

    1994-01-01

    The long-wavelength thermal anomalies in the lower mantle have been mapped out using several seismic tomographic models in conjunction with thermodynamic parameters derived from high-pressure mineral physics experiments. These parameters are the depth variations of thermal expansivity and of the proportionality factor between changes in density and seismic velocity. The giant plume-like structures in the lower mantle under the Pacific Ocean and Africa have outer fringes with thermal anomalies around 300-400 K, but very high temperatures are found in the center of the plumes near the base of the core-mantle boundary. These extreme values can exceed +1500 K and may reflect large hot thermal anomalies in the lower mantle, which are supported by recent measurements of high melting temperatures of perovskite and iron. Extremely cold anomalies, around -1500 K, are found for anomalies in the deep mantle around the Pacific rim and under South America. Numerical simulations show that large negative thermal anomalies in the mid-lower mantle have modest magnitudes of around -500 K. correlation pattern exists between the present-day locations of cold masses in the lower mantle and the sites of past subduction since the Cretaceous. Results from correlation analysis show that the slab mass-flux in the lower mantle did not conform to a steady-state nature but exhibited time-dependent behavior.

  1. Evolution of geothermal fluids deduced from chemistry plots: Yellowstone National Park (U.S.A.)

    USGS Publications Warehouse

    Mazor, E.; Thompson, J.M.

    1982-01-01

    Large amounts of chemical data, obtained in geothermal fields, may readily be sorted-out by the aid of a simple set of graphs that provide a clear over-all picture and facilitate the understanding of geochemical processes taking place. As a case study, data from several hundred samples of the thermal springs at the well-known Yellowstone National Park are discussed. The pattern obtained seems to indicate: (1) geochemical similarity between the spring groups of Heart Lake, Shoshone, Upper, Midway, Lower and Norris Geyser Basins, i.e., a geochemical uniformity of major spring groups located over 40 km apart; (2) these groups may be described as originating from a common fluid, most resembling the composition of Norris waters, accompanied by CO2, and other volatiles, that react with igneous rocks, forming local variations; (3) the secondary reactions occur at (medium) depth, before the ascent to the surface; (4) extensive concentration-dilution processes occur during the ascent to the surface. The water of the Mammoth group may be described as originating from the same Norris-like fluid that has been diluted (low Na and Cl contents) and intensively reacted with carbonaceous rocks, thus gaining in Ca, Mg, SO4, and HCO3. ?? 1982.

  2. Deducing mineral weathering reactions from solute profiles in highly leached regolith, Luquillo Mountains, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Buss, H. L.; White, A. F.; Vivit, D. V.; Fitzpatrick, J.; Bullen, T. D.; Blum, A.; Schulz, M. S.; Dessert, C.; Gaillardet, J.

    2009-12-01

    Porewater solute fluxes are measured on a smaller spatial scale than watershed fluxes and can thus provide more information on the mechanisms of weathering and nutrient cycling processes as well as a more accurate estimate of mineral weathering rates. Mineral weathering reactions continue influence mineral nutrient cycles even in thick, highly leached regolith. As part of the USGS Water Energy and Biogeochemical Budgets (WEBB) program and the Critical Zone Exploration Network, we are investigating mineral nutrient distributions and fluxes in depth profiles in the Bisley 1 catchment in the Luquillo Mountains of Puerto Rico for comparison to the nearby Rio Icacos catchment. Both watersheds are steep, rugged, humid, and tropical, have similar vegetation and land-use, and contain thick, well drained saprolites developed on igneous bedrock: a quartz diorite intrusion in the Rio Icacos, and a marine bedded, andesitic volcaniclastic in the Bisley. Depth distributions of physical parameters (density, porosity, water saturation) and chemistry of solids and solutes were determined. Vertical water infiltration rates in the Bisley watershed average about 4 m y-1, while infiltration rates in the Rio Icacos are about 1 m y-1 (White et al., 1998), and fluid residence times average 8 years in Rio Icacos versus 2 years in Bisley. Porosity in the Bisley regolith is slightly higher at most depths than in the Rio Icacos. The Bisley regolith is highly weathered and is depleted in primary minerals (except quartz) with respect to bedrock, while the Rio Icacos regolith contains residual biotite, which produces a Mg solute gradient with depth (White et al., 1998). The Bisley regolith also exhibits Mg solute gradients among others (notably Si); however, to date, no Mg-containing minerals have been identified in the regolith. Mg and Sr isotope ratios were measured in the pore waters at the Institut de Physique du Globe de Paris. The Mg isotope ratios increase with increasing depth from δ26Mg = -0.772 at the surface to -0.267 at 9.3 m depth, relative to the DSM3 standard. Sr isotope ratios vary from 0.71044 near the surface to 0.70692 87Sr/86Sr at 9.3 m depth. These solute gradients in Mg and Sr isotope ratios with depth suggest mixing lines between an atmospheric component at the surface and a weathering component at depth. The isotopic data indicate that even in this thick, highly weathered profile with high water infiltration rates, weathering reactions are occurring and affecting mineral nutrient cycles. White A.F. et al. (1998) Geochim. Cosmochim. Acta 62, 209-226.

  3. The production rate of cosmogenic 21-Ne in chondrites deduced from 81-Kr measurements

    NASA Technical Reports Server (NTRS)

    Schultz, L.; Freundel, M.

    1986-01-01

    Cosmogenic Ne-21 is used widely to calculate exposure ages of stone meteorites. In order to do so, the production rate P(21) must be known. This rate, however, is dependent on the chemical composition of the meteorite as well as the mass of, and position within, the meteoroid during its exposure to the cosmic radiation. Even for a mean shielding the production rates determined from measurments of different radionuclides vary by a factor of two. A method that can be used to determine exposure ages of meteorites that avoids shielding and chemical composition corrections is the -81-Kr-Kr-method. However, for chondrites, in many cases, the direct determination of production rates for the Kr isotopes is prevented by the trapped gases and the neutron effects on bromine. Therefore, this method was applied to four eucrite falls and then their 81-Kr-83-Kr-ages were compared to their cosmogenic Ne-21 and Ar-38 concentrations. The eucrites Bouvante-le-Haut, Juvinas, Sioux County, and Stannern were chosen for these measurements because of their similar chemical composition regarding the major elements.

  4. Atomic oxygen on the Venus nightside: Global distribution deduced from airglow mapping

    NASA Astrophysics Data System (ADS)

    Soret, L.; Gérard, J.-C.; Montmessin, F.; Piccioni, G.; Drossart, P.; Bertaux, J.-L.

    2012-02-01

    The Visible and Infra-Red Thermal Imaging Spectrometer (VIRTIS) instrument on board the Venus Express spacecraft has measured the O 2(a 1Δ) nightglow distribution at 1.27 μm in the Venus mesosphere for more than two years. Nadir observations have been used to create a statistical map of the emission on Venus nightside. It appears that the statistical 1.6 MR maximum of the emission is located around the antisolar point. Limb observations provide information on the altitude and on the shape of the emission layer. We combine nadir observations essentially covering the southern hemisphere, corrected for the thermal emission of the lower atmosphere, with limb profiles of the northern hemisphere to generate a global map of the Venus nightside emission at 1.27 μm. Given all the O 2(a 1Δ) intensity profiles, O 2(a 1Δ) and O density profiles have been calculated and three-dimensional maps of metastable molecular and atomic oxygen densities have been generated. This global O density nightside distribution improves that available from the VTS3 model, which was based on measurements made above 145 km. The O 2(a 1Δ) hemispheric average density is 2.1 × 10 9 cm -3, with a maximum value of 6.5 × 10 9 cm -3 at 99.2 km. The O density profiles have been derived from the nightglow data using CO 2 profiles from the empirical VTS3 model or from SPICAV stellar occultations. The O hemispheric average density is 1.9 × 10 11 cm -3 in both cases, with a mean altitude of the peak located at 106.1 km and 103.4 km, respectively. These results tend to confirm the modeled values of 2.8 × 10 11 cm -3 at 104 km and 2.0 × 10 11 cm -3 at 110 km obtained by Brecht et al. [Brecht, A., Bougher, S.W., Gérard, J.-C., Parkinson, C.D., Rafkin, S., Foster, B., 2011a. J. Geophys. Res., in press] and Krasnopolsky [Krasnopolsky, V.A., 2010. Icarus 207, 17-27], respectively. Comparing the oxygen density map derived from the O 2(a 1Δ) nightglow observations, it appears that the morphology is very different and that the densities obtained in this study are about three times higher than those predicted by the VTS3 model.

  5. Iron Fertilization in the Southern Ocean Deduced From Environmental Magnetism of Sediment Cores

    NASA Astrophysics Data System (ADS)

    Yamazaki, T.; Ikehara, M.

    2012-12-01

    With rock-magnetic technique, biogenic magnetites in sediments can be detected utilizing the characteristics of almost no magnetostatic interactions and narrow coercivity distribution, reflecting occurrence of single-domain magnetites in a chain (e.g., Egli et al., 2010; Roberts et al., 2011). Magnetic mineral assemblages in pelagic sediments of Pacific and Indian Oceans often have two distinctive constituents; the first is characterized by non-interacting on first-order reversal curve (FORC) diagrams and low-coercivity (~40 mT) with small dispersion on isothermal remanent magnetization (IRM) component analyses, and the second is characterized by interacting and middle-coercivity (~100 mT). The former is interpreted as biogenic magnetites and the latter is terrigenous maghemites (Yamazaki, 2009; 2012). The ratio of anhysteretic remanent magnetization susceptibility to saturation IRM reflects relative abundance of the biogenic and terrigenous components. In the Southern Ocean, magnetic mineral concentration increases in glacial periods. The variation pattern closely resembles eolian dust flux records from Antarctic ice cores, but the cause of the linkage was unclear, as the dust flux is too small for the source of terrigenous materials in the Southern Ocean. Our environmental magnetic study of late Pleistocene sediments from the south Indian Ocean revealed that biogenic magnetites are a dominant constituent of the magnetic minerals. In glacials, the abundance of both biogenic and terrigenous components increased with increased proportions of the latter. Increased ocean productivity in glacials is suggested from increased proportions of biogenic magnetites with elongated morphologies, indicative of less-oxic conditions, and increased sedimentation rates. These observations suggest that the increased magnetic concentration in glacials in the Southern Ocean may be explained by iron fertilization; the production of biogenic magnetites was enhanced associated with increased ocean productivity, which was fueled by increased eolian dust flux. In pelagic clay cores in the North Pacific, the contributions of biogenic and terrigenous components to IRM are comparative. The abundance of the terrigenous component increases in glacials, whereas the biogenic component increases in interglacials. This suggests that iron fertilization did not occur in the North Pacific; increased eolian dust flux from the Asian continent in glacials did not promote production of biogenic magnetites.

  6. A 350 Year Cloud Cover Reconstruction Deduced from Caribbean Coral Proxies

    NASA Astrophysics Data System (ADS)

    Winter, Amos; Sammarco, Paul; Mikolajewicz, Uwe; Jury, Mark; Zanchettin, Davide

    2015-04-01

    Clouds are a major factor contributing to climate change with respect to a variety of effects on the earth's climates, primarily radiative effects, amelioration of heating, and regional changes in precipitation patterns. There have been very few studies of decadal and longer term changes in cloud cover in the tropics and sub-tropics, both over land and the ocean. In the tropics, there is great uncertainty regarding how global warming will affect cloud cover. Observational satellite data is so short that it is difficult to discern any temporal trends. The skeletons of scleractinian corals are considered to contain among the best records of high-resolution (sub-annual) environmental variability in the tropical and sub-tropical oceans. Corals generally live in well-mixed coastal regions and can often record environmental conditions of large areas of the upper ocean. This is particularly the case at low latitudes. Scleractinian corals are sessile, epibenthic fauna, and the type of environmental information recorded at the location where the coral has been living is dependent upon the species of coral considered and proxy index of interest. Zooxanthellate hermatypic corals in tropical and sub-tropical seas precipitate CaCO3 skeletons as they grow. This growth is made possible through the manufacture of CaCO3 crystals, facilitated by the zooxanthellae. During the process of crystallization, the holobiont binds carbon of different isotopes into the crystals. Stable carbon isotope concentrations vary with a variety of environmental conditions. In the Caribbean, δ13C in corals of the species Montastraea faveolata can be used as a proxy for changes in cloud cover. In this contribution, we will demonstrate that the stable isotope 13C varies concomitantly with cloud cover and present a new reconstruction of cloud cover over the Caribbean Sea that extends back to the year 1760. We will show that there is good agreement between the main features of our coral proxy record of cloud cover and of reanalysis and climate simulations for the same time period.

  7. Curie depth map for Sinai Peninsula, Egypt deduced from the analysis of magnetic data

    NASA Astrophysics Data System (ADS)

    Aboud, Essam; Salem, Ahmed; Mekkawi, Mahmoud

    2011-06-01

    Sinai Peninsula is considered as a unique region in the world due to its geographical location, tectonic and thermal activities. It is located geographically at the crossroads of Europe, Asia, and Africa constituting a triple junction point between the three continents. It is also characterized by thermal manifestations represented by several hot springs with varied temperatures (30-70 °C). Most of these hot springs are located along the shoreline of the Gulf of Suez. In this study, we aim to map the Curie depth isotherm surface for Sinai Peninsula based on the analysis of ground magnetic data. Spectral analysis technique will be used to estimate the boundaries (top and bottom) of the magnetized crust. The depths obtained for the bottom of magnetized crust are assumed to correspond to Curie point depths where the magnetic layer loss its magnetization. Results of this study indicate that the shallow Curie depths (~ 15-18 km) are located at the southern part of Sinai Peninsula and along the shoreline of the Gulf of Suez and depths increase (22-25 km) towards the central and north western portions of Sinai Peninsula. The whole average Curie depth point of Sinai Peninsula is about 20 km. Generally, the shallow depths to Curie isotherm indicate that Sinai Peninsula is a promising area for further geothermal exploration particularly near the eastern side of the Gulf of Suez.

  8. Fishing for biodiversity: Novel methanopterin-linked C1 transfergenes deduced from the Sargasso Sea metagenome

    SciTech Connect

    Kalyuzhnaya, Marina G.; Nercessian, Olivier; Lapidus, Alla; Chistoserdova, Ludmila

    2004-07-01

    The recently generated database of microbial genes from anoligotrophic environment populated by a calculated 1,800 of major phylotypes (the Sargasso Sea metagenome) presents a great source for expanding local databases of genes indicative of a specific function. In this paper we analyze the Sargasso Sea metagenome in terms of the presence of methanopterin-linked C1 transfer genes that are signature for methylotrophy. We conclude that more than 10 phylotypes possessing genes of interest are present in this environment, and a few of these are relatively abundant species. The sequences representative of the major phylotypes do not appear to belong to any known microbial group capable of methanopterin-linked C1 transfer. Instead, they separate from all known sequences on phylogenetic trees, pointing towards their affiliation with a novel microbial phylum. These data imply a broader distribution of methanopterin-linked functions in the microbial world than previously known.

  9. Evolutionary relationships among members of the Bromoviridae deduced from whole proteome analysis.

    PubMed

    Codoñer, F M; Elena, S F

    2006-02-01

    Many molecular phylogenies of viruses build upon the analysis of single genes. The study of whole-genomes, however, might yield more reliable information to infer tree topologies and a better approach for drawing the evolutionary history of virus families. In this study, we apply a novel comparative proteomic approach to seek whether incorporating information from the entire proteome would support the actual taxonomy of the family Bromoviridae. Our results suggest that the current taxonomic classification should be modified in several aspects to account for the genomic properties of the Bromoviridae. These differences are: i) Alfalfa mosaic virus (AMV) is a true Ilarvirus instead of constituting an independent genus; ii) Pelargonium zonate spot virus (PZSV) should be considered as a member of the Bromoviridae; and iii) the genus Ilarvirus should be divided into fewer phylogenetic subgroups than suggested by antigenic differences. PMID:16172839

  10. Transport in the Region of the Subtropical Jet Deduced From WB-57 Measurements and Mesoscale Modeling

    NASA Astrophysics Data System (ADS)

    Ray, E.; Ray, E.; Rosenlof, K. H.

    2001-12-01

    Recent WB-57 missions have provided a wealth of long-lived tracer and aerosol measurements in the upper troposphere and lower stratosphere. In this study we use in situ water vapor, ozone and meteorological measurements as well as vertical sounding data to investigate transport in the region of the subtopical jet. In addition, mesoscale model simulations from the NCAR MM5 are utilized to attempt to reproduce the observations and help determine possible mechanisms of transport. We focus on the flight of May 7, 1998 since it has several interesting features in the measurements taken as the flight crossed a jet exit region at roughly the 370 K level. On the tropical side of the jet, low water vapor and relatively high ozone mixing ratios were measured suggesting the air in this region had stratospheric characteristics. Yet according to MM5 output this region is well within the troposphere. Within the jet the water vapor mixing ratios are highly variable, with some mixing ratios higher than those measured on either side of the jet at the same isentropic level. This suggests that perhaps there was more vertical mixing within the jet than on either side of the jet. A third interesting feature in the measurements is seen several hundred km north of the jet just as the plane began to rise in altitude. Between 370-390K the water vapor increased sharply and the ozone decreased sharply at the same time the MTP instrument indicated the tropopause level had risen from 345 K to 370 K in less than 50 km. This feature is highly suggestive of a small filament of upper tropospheric air which has been transported to the north side of the jet. Each of these features is compared to MM5 output and trajectory analyses.

  11. Late-glacial to Holocene transition in northern Spain deduced from land-snail shelly accumulations

    NASA Astrophysics Data System (ADS)

    Yanes, Yurena; Gutiérrez-Zugasti, Igor; Delgado, Antonio

    2012-09-01

    Shells of the helicid Cepaea nemoralis were studied using taphonomic, isotopic and morphometric measurements to estimate late glacial-Holocene (~ 12.1-6.3 cal ka BP) environmental conditions in northern Spain. Higher taphonomic alteration among Holocene shells suggests lower sedimentation rates or higher shell-destruction rates than during glacial conditions. Shells preserved the aragonitic composition despite differing degree of skeleton damage. Shell δ13C values were - 10.3 ± 1.1‰, - 8.2 ± 2.3‰, and - 7.3 ± 1.6‰ for modern, Holocene and late-glacial individuals, respectively. Higher δ13C values during the late-glacial and some Holocene periods imply higher water stress of C3 plants and/or higher limestone contribution than today. Intrashell δ13C values were higher during juvenile stages suggesting higher limestone ingestion to promote shell growth. Shell δ18O values were - 1.1 ± 0.7‰, - 0.9 ± 0.8‰ and - 0.1 ± 0.7‰ for modern, Holocene and late-glacial specimens, respectively. A snail flux-balance model suggests that during ~ 12.1 - 10.9 cal ka BP conditions were drier and became wetter at ~ 8.4 - 6.3 cal ka BP and today. Intrashell δ18O profiles reveal that glacial individuals experienced more extreme seasonality than interglacial shells, despite possible larger hibernation periods. Shell size correlated positively with δ18O values, suggesting that growth rates and ultimate adult size of C. nemoralis may respond to climate fluctuation in northern Spain.

  12. The osmium isotopic composition of convecting upper mantle deduced from ophiolite chromites

    NASA Astrophysics Data System (ADS)

    Walker, Richard J.; Prichard, Hazel M.; Ishiwatari, Akira; Pimentel, Márcio

    2002-01-01

    Chromites separated from the upper mantle or lower crustal portions of 18 ophiolites ranging in age from 900 Ma to 50 Ma are examined for Re-Os isotopic systematics. The ophiolites include both MORB and back arc types, although most are from supra-subduction zone (SSZ) settings. The chromites are robust indicators of the initial Os isotopic compositions of the systems sampled. There is very limited range in calculated initial γ Os values, with the entire group averaging +1.31. Least squares linear regression of the age of chromite formation (in Ga) versus initial 187Os/ 188Os of a filtered suite yields a slope of -0.0058±0.0019 (2σ) and a present day intercept of 0.12809±0.00085 (2σ), equivalent to a γ Os value of +0.9±0.6. Of the suite of 51 samples analyzed, 68% lie within ±1% of this evolution trajectory. Although most of the samples formed in SSZ environments, there is little evidence to suggest modification of the mantle Os isotopic composition via radiogenic melts or fluids derived from subducting slabs. The ophiolite data are interpreted as representative of the convecting upper mantle and suggest that the present isotopic composition of the convecting upper mantle averages approximately 1.2% less radiogenic than the estimated minimum composition of the primitive upper mantle of 0.1296±8 (Meisel et al., 2001). The most likely explanation for the difference is the formation, subduction and isolation of some portion of the mafic oceanic crust. Using models based on the assumption that the convecting upper mantle comprises 50% of the total mass of the mantle, and that the average isolation period for subducted oceanic crust is 1.5 to 2.0 Ga, it is estimated that approximately 2 to 3% of the total mass of the mantle is composed of subducted mafic oceanic crust that remains isolated from the convecting upper mantle. Because the isotopic compositions of the DMM and PUM overlap within uncertainties, however, the results do not require any isolated slab component.

  13. Une Experience Novatrice en Guinee-Bissau: Les Centres D'education Populaire Integree (CEPI)

    NASA Astrophysics Data System (ADS)

    Colin, Roland

    1980-09-01

    Since Guinea-Bissau attained independence, it has endeavoured to define a new system of education inspired chiefly by the experience gained in the liberated zones during the period of armed struggle. Thus, when primary education was extended by two years (from 4 to 6 years), an experiment with Centres of Integrated Popular Education (CEPI) was launched in 1977 in the region of Tombali in the Balante area. The present article gives an account of this altogether novel experiment. It underlines the basic principles of the CEPI: to involve adults in the elaboration of educational programmes; to introduce an alternation of school (where the children spend four days) with the community (where they spend the three following days); to link education with transformation. First evaluations have shown the interest taken by farmers in this new education system, which has now been extended to other regions of the country. However, major problems continue to arise, especially that of preparing new educators capable of reproducing the original pedagogical approach followed in the experimental zone without distorting it, and the problem of articulation of the CEPI with the rest of the educational system.

  14. Lateral temperature variations at the core-mantle boundary deduced from the magnetic field

    NASA Technical Reports Server (NTRS)

    Bloxham, Jeremy; Jackson, Andrew

    1990-01-01

    Recent studies of the secular variation of the earth's magnetic field over periods of a few centuries have suggested that the pattern of fluid motion near the surface of earth's outer core may be strongly influenced by lateral temperature variations in the lowermost mantle. This paper introduces a self-consistent method for finding the temperature variations near the core surface by assuming that the dynamical balance there is geostrophic and that lateral density variations there are thermal in origin. As expected, the lateral temperature variations are very small. Some agreement is found between this pattern and the pattern of topography of the core-mantle boundary, but this does not conclusively answer to what extent core surface motions are controlled by the mantle, rather than being determined by processes in the core.

  15. Deduced amino acid sequence of human pulmonary surfactant proteolipid: SPL(pVal)

    SciTech Connect

    Whitsett, J.A.; Glasser, S.W.; Korfhagen, T.R.; Weaver, T.E.; Clark, J.; Pilot-Matias, T.; Meuth, J.; Fox, J.L.

    1987-05-01

    Hydrophobic, proteolipid-like protein of Mr 6500 was isolated from ether/ethanol extracts of human, canine and bovine pulmonary surfactant. Amino acid composition of the protein demonstrated a remarkable abundance of hydrophobic residues, particularly valine and leucine. The N-terminal amino acid sequence of the human protein was determined: N-Leu-Ile-Pro-Cys-Cys-Pro-Val-Asn-Leu-Lys-Arg-Leu-Leu-Ile-Val4... An oligonucleotide probe was used to screen an adult human lung cDNA library and resulted in detection of cDNA clones with predicted amino acid sequence with close identity to the N-terminal amino acid sequence of the human peptide. SPL(pVal) was found within the reading frame of a larger peptide. SPL(pVal) results from proteolytic processing of a larger preprotein. Northern blot analysis detected in a single 1.0 kilobase SPL(pVal) RNA which was less abundant in fetal than in adult lung. Mixtures of purified canine and bovine SPL(pVal) and synthetic phospholipids display properties of rapid adsorption and surface tension lowering activity characteristic of surfactant. Human SPL(pVal) is a pulmonary surfactant proteolipid which may therefore be useful in combination with phospholipids and/or other surfactant proteins for the treatment of surfactant deficiency such as hyaline membrane disease in newborn infants.

  16. Identification of widespread pollution in the southern hemisphere deduced from satellite analyses. [AFRICA

    SciTech Connect

    Fishman, J. ); Fakhruzzaman, K. ); Cros, B.; Nganga, D. )

    1991-06-21

    Vertical profiles of ozone obtained from ozonesondes in Brazzaville, Congo (4{degree}S, 15{degree}E), and Ascension Island (98{degree}S, 15{degree}W) show that large quantities of tropospheric ozone are present over southern Africa and the adjacent eastern tropical South Atlantic Ocean. The origin of this pollution is widespread biomass burning in Africa. These measurements support satellite-derived tropospheric ozone data that demonstrate that ozone originating from the region is transported throughout most of the Southern Hemisphere. Seasonally high levels of carbon monoxide and methane observed at middle- and high-latitude stations in Africa, Australia, and Antarctica likely reflect the effects of this distant biomass burning. These data suggest that even the most remote regions on this planet may be significantly more polluted than previously believed.

  17. Global lightning dynamics deduced from Schumann resonance frequency variations at two sites ~ 550 km apart

    NASA Astrophysics Data System (ADS)

    Satori, G.; Mushtak, V.; Neska, M.; Nagy, T.; Barta, V.

    2012-04-01

    Schumann resonance (SR) peak frequencies depend on the lightning source-observer angular distance. The modal phase shift interaction at nodal distances manifests itself as sharp frequency variations: increases or decreases depend on the direction of the source motion with respect to the observer and the mode number. Nagycenk Observatory (47.6° N, 16.7° E), Hungary and Belsk (51.8 ° N, 20.8 ° E), Poland, are relatively close to each other ( ~550 km apart) compared with SR wavelengths. Both stations can approach the nodal position with respect to the African source region for the third Ez mode and to the Asian/American "chimney" regions for the first Ez mode as lightning activity migrates as the seasons change. These two observation sites can be on the different sides of the nodal line region for some weeks twice during a year, indicating the fine seasonal motion of the source regions which causes relatively large frequency variations (some tenth Hz) and different frequency values at the two stations, especially for the third Ez mode. Source-observer distance dependent frequency variations are presented throughout a year by using simultaneous SR observations at Nagycenk (NCK) and Belsk (BLK). The observed frequency changes are supported by the simulation of the distance-dependent frequency variation based on the computed spectra of the vertical electric field components using the Two-Dimensional Telegraph Equation (TDTE) technique (Kirillov, 2002). For the tropical "chimney" regions the diurnal phase of greatest activity has well established spatial-temporal dynamics. Modal peak frequencies are obtained, along with modal intensities and quality factors, by means of the least-squares fitting of "experimental" spectra by the "classic" Lorentzian function (Williams et al., 2006).

  18. Surface currents in the Caribbean Sea as deduced from lagrangian observations

    SciTech Connect

    Molinari, R.L.; Spillane, M.; Brooks, I.; Atwood, D.; Duckett, C.

    1981-07-20

    The results of a satellite tracked drifting buoy experiment conducted in the Caribbean Sea from October 1975 through June 1976 are presented. The buoy trajectories suggest that the Aves Rise, Beata Ridge, and Nicaraguan Rise are regions where considerable mesoscale variability occurs in the surface flow. The variability is in the form of current deflections; small diameter eddies ranging in size from 20 to 100 km; large amplitude meanders, with amplitudes greater than 150 km; and large diameter eddies, with diameters greater than 200 km which form on and near these rises and ridges. In the central Caribbean, where the topographic relief is not as dramatic, the flow is predominantly zonal. Intensifications in the surface flow occur off the coast of Colombia, south of the Nicaraguan Rise, and south of the Yucatan Strait.

  19. Personality Theories Facilitate Integrating the Five Principles and Deducing Hypotheses for Testing

    ERIC Educational Resources Information Center

    Maddi, Salvatore R.

    2007-01-01

    Comments on the original article "A New Big Five: Fundamental Principles for an Integrative Science of Personality," by Dan P. McAdams and Jennifer L. Pals (see record 2006-03947-002). In presenting their view of personality science, McAdams and Pals (April 2006) elaborated the importance of five principles for building an integrated science of…

  20. Paleoclimate variability during the Blake geomagnetic excursion (MIS 5d) deduced from a speleothem record

    NASA Astrophysics Data System (ADS)

    Rossi, Carlos; Mertz-Kraus, Regina; Osete, María-Luisa

    2014-10-01

    To evaluate possible connections between climate and the Earth's magnetic field, we examine paleoclimate proxies in a stalagmite (PA-8) recording the Blake excursion (˜112-˜116.4 ka) from Cobre cave (N Spain). Trace element, δ13C, δ18O, δ234U, fluorescent lamination, growth rate, and paleomagnetic records were synchronized using a floating lamina-counted chronology constrained by U-Th dates, providing a high-resolution multi-proxy paleoclimate record for MIS 5d. The alpine cave setting and the combination of proxies contributed to improve the confidence of the paleoclimatic interpretation. Periods of relatively warm and humid climate likely favored forest development and resulted in high speleothem growth rates, arguably annual fluorescent laminae, low δ13C and [Mg], and increased [Sr] and [Ba]. Colder periods limited soil activity and drip water availability, leading to reduced speleothem growth, poor development of fluorescent lamination, enhanced water-rock interaction leading to increased [Mg], δ13C, and δ234U, and episodic flooding. In the coldest and driest period recorded, evaporation caused simultaneous 18O and 13C enrichments and perturbed the trace element patterns. The Blake took place in a relatively warm interestadial at the inception of the Last Glacial period, but during a global cooling trend recorded in PA-8 by an overall decrease of δ18O and growth rate and increasing [Mg]. That trend culminated in the cessation of growth between ˜112 and ˜101 ka likely due to the onset of local glaciation correlated with Greenland stadial 25. That trend is consistent with a link between low geomagnetic intensity and climate cooling, but it does not prove it. Shorter term changes in relative paleointensity (RPI) relate to climate changes recorded in PA-8, particularly a prominent RPI low from ˜114.5 to ˜113 ka coincident with a significant cooling indicated by all proxy records, suggesting a link between geomagnetic intensity and climate at millennial time scales. Although the reliability of such inference is limited by the inferior resolution of the paleomagnetic data and a possible contamination of the RPI data by unaccounted changes in magnetite concentration, the agreement of those data with the marine record of cosmogenic Be suggests that the RPI record of PA-8 may reflect truly geomagnetic intensity variations.

  1. Formation des enseignants dans une perspective d'education permanente au benin

    NASA Astrophysics Data System (ADS)

    Agboton, Sébastien; Moussa, Yaya Mede

    1994-05-01

    The history of teacher training in Benin, which provides evidence of social and cultural change, suggests that a system of lifelong education should be introduced which unites formal, non-formal and informal education, all of which already exist in embryo. The education originally given to every member of society was a continuing progression from initiate to initiator, a lifelong education that involved, among other things, knowledge of agricultural production. This traditional system was disrupted by the reorganization of teacher training after 1945. Recurrent training of teachers remained inadequate because of limited external funding for in-service training, the lack of teachers, the suspension of recruitment and the closure of teacher training colleges. The 1975 reform, through the initiative known as Operation Education and Development, envisaged links between school and social environment, allying intellectual work with production. This meant a radical change in the role of the teacher, who was confronted with technical advance and was obliged to enter a difficult continuing process of self-training. Furthermore, population growth and the restrictions imposed by the World Bank have brought about developments in both lifelong learning and apprenticeship. These two elements are brought together under an initiative known as Production Scolaire Artisanale, designed for out-of-school learners and artisans. The author concludes that the creation of a coherent system of voluntary education would be possible in a society that was itself favourably disposed to education.

  2. Two-proton decay of the isobaric analogue state of 31Ar

    NASA Astrophysics Data System (ADS)

    Mukha, I.; Axelsson, L.; Äystö, J.; Bergmann, U. C.; Borge, M. J. G.; Fraile, L. M.; Fynbo, H. O. U.; Honkanen, A.; Hornshøj, P.; Jading, Y.; Jonson, B.; Jokinen, A.; Martel, I.; Oinonen, M.; Nilsson, T.; Nyman, G.; Petersen, B.; Riisager, K.; Siiskonen, T.; Smedberg, M. H.; Tengblad, O.; Wenander, F.; Isolde Collaboration

    1998-02-01

    We have studied several two proton branches in the β-decay of 31Ar, the most intensive ones proceeding through the isobaric analogue state (IAS) in 31Cl. The energy and angular correlations of the two protons originating from the IAS have been measured. An indication of non-isotropic emission has been observed in the p+p+ 29P branch. The energy spectra of protons from the IAS 2p-branches seem to be continuous, which is difficult to explain by a sequential emission through a few intermediate levels in 30S. The model of non-sequential or democratic three-particle decay gives the best fit to the present data favoring the IAS spin-parity {5}/{2 +}.

  3. Elucidation of Echovirus 30's Origin and Transmission during the 2012 Aseptic Meningitis Outbreak in Guangdong, China, through Continuing Environmental Surveillance

    PubMed Central

    Lu, Jing; Guo, Xue; Zhang, Yong; Li, Hui; Liu, Leng; Zeng, Hanri; Fang, Ling; Mo, Yanling; Yoshida, Hiromu; Yi, Lina; Liu, Tao; Rutherford, Shannon; Xu, Wenbo; Ke, Changwen

    2015-01-01

    An aseptic meningitis outbreak occurred in Luoding City of Guangdong, China, in 2012, and echovirus type 30 (ECHO30) was identified as the major causative pathogen. Environmental surveillance indicated that ECHO30 was detected in the sewage of a neighboring city, Guangzhou, from 2010 to 2012 and also in Luoding City sewage samples (6/43, 14%) collected after the outbreak. In order to track the potential origin of the outbreak viral strains, we sequenced the VP1 genes of 29 viral strains from clinical patients and environmental samples. Sequence alignments and phylogenetic analyses based on VP1 gene sequences revealed that virus strains isolated from the sewage of Guangzhou and Luoding cities matched well the clinical strains from the outbreak, with high nucleotide sequence similarity (98.5% to 100%) and similar cluster distribution. Five ECHO30 clinical strains were clustered with the Guangdong environmental strains but diverged from strains from other regions, suggesting that this subcluster of viruses most likely originated from the circulating virus in Guangdong rather than having been more recently imported from other regions. These findings underscore the importance of long-term, continuous environmental surveillance and genetic analysis to monitor circulating enteroviruses. PMID:25616804

  4. Elucidation of echovirus 30's origin and transmission during the 2012 aseptic meningitis outbreak in Guangdong, China, through continuing environmental surveillance.

    PubMed

    Lu, Jing; Zheng, Huanying; Guo, Xue; Zhang, Yong; Li, Hui; Liu, Leng; Zeng, Hanri; Fang, Ling; Mo, Yanling; Yoshida, Hiromu; Yi, Lina; Liu, Tao; Rutherford, Shannon; Xu, Wenbo; Ke, Changwen

    2015-04-01

    An aseptic meningitis outbreak occurred in Luoding City of Guangdong, China, in 2012, and echovirus type 30 (ECHO30) was identified as the major causative pathogen. Environmental surveillance indicated that ECHO30 was detected in the sewage of a neighboring city, Guangzhou, from 2010 to 2012 and also in Luoding City sewage samples (6/43, 14%) collected after the outbreak. In order to track the potential origin of the outbreak viral strains, we sequenced the VP1 genes of 29 viral strains from clinical patients and environmental samples. Sequence alignments and phylogenetic analyses based on VP1 gene sequences revealed that virus strains isolated from the sewage of Guangzhou and Luoding cities matched well the clinical strains from the outbreak, with high nucleotide sequence similarity (98.5% to 100%) and similar cluster distribution. Five ECHO30 clinical strains were clustered with the Guangdong environmental strains but diverged from strains from other regions, suggesting that this subcluster of viruses most likely originated from the circulating virus in Guangdong rather than having been more recently imported from other regions. These findings underscore the importance of long-term, continuous environmental surveillance and genetic analysis to monitor circulating enteroviruses. PMID:25616804

  5. Quinine, Malaria, and the Cinchona Bureau: Marketing Practices and Knowledge Circulation in a Dutch Transoceanic Cinchona-Quinine Enterprise (1920s-30s).

    PubMed

    Van Der Hoogte, Arjo Roersch; Pieters, Toine

    2016-04-01

    In this study, we will show how a Dutch pharmaceutical consortium of cinchona producers and quinine manufacturers was able to capitalize on one of the first international public health campaigns to fight malaria, thereby promoting the sale of quinine, an antimalarial medicine. During the 1920s and 1930s, the international markets for quinine were controlled by this Dutch consortium, which was a transoceanic cinchona-quinine enterprise centered in the Cinchona Bureau in the Netherlands. We will argue that during the interwar period, the Cinchona Bureau became the decision-making center of this Dutch cinchona-quinine pharmaceutical enterprise and monopolized the production and trade of an essential medicine. In addition, we will argue that capitalizing on the international public health campaign in the fight against malaria by the Dutch cinchona-quinine enterprise via the Cinchona Bureau can be regarded as an early example of corporate colonization of public health by a private pharmaceutical consortium. Furthermore, we will show how commercial interests prevailed over scientific interests within the Dutch cinchona-quinine consortium, thus interfering with and ultimately curtailing the transoceanic circulation of knowledge in the Dutch empire. PMID:26054829

  6. In your 20s it's quantity, in your 30s it's quality: the prognostic value of social activity across 30 years of adulthood.

    PubMed

    Carmichael, Cheryl L; Reis, Harry T; Duberstein, Paul R

    2015-03-01

    Social connection, a leading factor in the promotion of health, well-being, and longevity, requires social knowledge and the capacity to cultivate intimacy. Life span development theorists have speculated that social information-seeking goals, emphasized at the beginning of early adulthood, give way to emotional closeness goals in later stages of early adulthood. Drawing on developmental theory (Baltes & Carstensen, 2003; Baltes, 1997), this 30-year prospective study assessed social activity at age 20 and age 30 with experience sampling methods, and psychosocial outcomes (social integration, friendship quality, loneliness, depression, and psychological well-being) at age 50. Results supported the hypothesis that the quantity (but not the quality) of social interactions at age 20, and the quality (but not the quantity) of social interactions at age 30 predict midlife psychosocial outcomes. Longitudinal structural models revealed that age-20 interaction quantity had a direct, unmediated effect on age-50 social and psychological outcomes. The effects of age-20 interaction quality on midlife outcomes, on the other hand, were mediated by age-30 interaction quality. Our findings are consistent with the idea that selection and optimization serve important functions in early adulthood, and that engaging in developmentally appropriate social activity contributes to psychosocial adjustment in the decades that follow. PMID:25774426

  7. Lacustrine records of the June 2011 eruption of the Puyehue-Cordón Caulle Volcanic Complex, Central Chile (40°30'S, 72°10'W)

    NASA Astrophysics Data System (ADS)

    Daga, Romina; Bertrand, Sébastien; Bedert, Robin; Ribeiro Guevara, Sergio; Ghazoui, Zakaria

    2013-04-01

    Present volcanic eruptions offer unique opportunities to study the dispersion and spatial variability of volcanic deposits. The objective of this work is to assess lateral variations of pyroclastic deposits from the June 2011 volcanic eruption of Puyehue-Cordon Caulle Volcanic Complex (PCCVC) by analyzing the sedimentology and geochemistry of tephra layers deposited in different lakes situated in North Patagonia (Chile and Argentina), located along the main dispersion axis of the volcanic cloud. Short sediment cores were extracted from selected lakes in Chile and Argentina using a short Uwitec gravity corer; coarse tephra deposits were collected with a grab sampler. The sediment cores were opened, visually inspected, photographed and described, and the magnetic susceptibility was measured with a Bartington MS3 meter and MS2E sensor. Visual inspection included the identification of the 2011 tephra layer, and the description of colour, grain size, thickness, and sedimentary structures of the sedimentary sequence. Subsequent studies were focused on the tephra layers. Samples were freeze-dried for multi-proxy analyses, including bulk mineralogy analyzed by X-ray diffraction and bulk geochemical characterization by Instrumental Neutron Activation Analysis. In this presentation, the main characterization features of the pyroclastic products will be presented, together with dispersion patterns. Lacustrine tephra deposits clearly reflected the predominance of westerlies, with thin deposits on the Chilean side of the volcano, but much thicker and coarser tephra close to the volcano. Ash dispersion extended hundreds of kilometers towards the east of the volcano, i.e., in Argentinean territory. Tephras deposited in water bodies in Chile are mainly transported from the eruptive center by rivers and watercourses with headwaters located in the volcano area, whereas tephra deposits in Argentinean lakes mainly result from direct ash falls. We also observed in-lakes variations in the sedimentological properties of the 2011 tephra in large lakes located to the West (Lake Puyehue) and to the East (Lake Nahuel Huapi) of the PCCVC. The characterization and precise understanding of this very recent eruption, and the observations of distribution patterns associated to wind directions and precipitation effects help us understand the mechanisms responsible for tephra deposition in lakes. Ultimately, this study will provide important clues to interpret tephra records from longer sediment cores, and improve tephra correlations on longer distances.

  8. Clockwise block rotations along the eastern border of the Cordillera de Domeyko, Northern Chile (22°45' 23°30'S)

    NASA Astrophysics Data System (ADS)

    Arriagada, César; Roperch, Pierrick; Mpodozis, Constantino

    2000-11-01

    We report new paleomagnetic results from a study of 38 sites in Cretaceous to Early Tertiary red beds and volcanic rocks belonging to the Purilactis Group, which outcrop along the western border of the Salar de Atacama Basin. After detailed thermal demagnetization, characteristic directions were determined for 32 units. In most cases, red bed sediments from the lower members of the Purilactis Group have a well-defined normal polarity magnetization probably carried by hematite forming an early diagenetic cement. A large decrease in the dispersion of the paleomagnetic directions upon tilt correction demonstrates that this magnetization is a pre-tectonic magnetization. We interpret the dominant occurrence of the normal polarity direction as evidence for acquisition of the magnetization during the Cretaceous normal polarity superchron. Large deviations of the paleomagnetic declinations from the expected ones for stable South America provides new evidence for clockwise tectonic rotations associated with Tertiary deformation in the Cordillera de Domeyko. These data confirm that clockwise tectonic rotations are one of the most significant structural characteristics of the north Chilean Andes. This study, however, indicates spatial variation in the magnitude of the rotation with rotations >60° in the Cerro Totola area. These rotations have occurred in conjunction with transpressional deformation that affected large tracts of the Cordillera de Domeyko during Eocene deformation. The systematic observation of clockwise rotations contemporaneous with sinistral displacements in the Cordillera de Domeyko can be explained by shear-traction at the base of the brittle crust.

  9. In Your 20s it’s Quantity, in Your 30s it’s Quality: The Prognostic Value of Social Activity Across 30 Years of Adulthood

    PubMed Central

    Carmichael, Cheryl L.; Reis, Harry T.; Duberstein, Paul R.

    2015-01-01

    Social connection, a leading factor in the promotion of health, well-being, and longevity, requires social knowledge and the capacity to cultivate intimacy. Lifespan development theorists have speculated that social information-seeking goals, emphasized at the beginning of early adulthood, give way to emotional closeness goals in later stages of early adulthood. Drawing on developmental theory (Baltes, 1997; Baltes & Carstensen, 2003), this 30-year prospective study assessed social activity at age-20 and age-30 with experience sampling methods, and psychosocial outcomes (social integration, friendship quality, loneliness, depression, and psychological well-being) at age-50. Results supported the hypothesis that the quantity (but not the quality) of social interactions at age-20, and the quality (but not the quantity) of social interactions at age-30 predict midlife psychosocial outcomes. Longitudinal structural models revealed that age-20 interaction quantity had a direct, unmediated effect on age-50 social and psychological outcomes. The effects of age-20 interaction quality on midlife outcomes, on the other hand, were mediated by age-30 interaction quality. Our findings are consistent with the idea that selection and optimization serve important functions in early adulthood, and that engaging in developmentally appropriate social activity contributes to psychosocial adjustment in the decades that follow. PMID:25774426

  10. Mid-lithospheric Discontinuity Beneath the Malawi Rift, Deduced from Gravity Studies and its Relation to the Rifting Process.

    NASA Astrophysics Data System (ADS)

    Njinju, E. A.; Atekwana, E. A.; Mickus, K. L.; Abdelsalam, M. G.; Atekwana, E. A.; Laó-Dávila, D. A.

    2015-12-01

    The World Gravity Map satellite gravity data were used to investigate the lithospheric structure beneath the Cenozoic-age Malawi Rift which forms the southern extension of the Western Branch of the East African Rift System. An analysis of the data using two-dimensional (2D) power spectrum methods indicates the two distinctive discontinuities at depths of 31‒44 km and 64‒124 km as defined by the two steepest slopes of the power spectrum curves. The shallower discontinuity corresponds to the crust-mantle boundary (Moho) and compares well with Moho depth determined from passive seismic studies. To understand the source of the deeper discontinuity, we applied the 2D power spectrum analysis to other rift segments of the Western Branch as well as regions with stable continental lithospheres where the lithospheric structure is well constrained through passive seismic studies. We found that the deeper discontinuity corresponds to a mid-lithospheric discontinuity (MLD), which is known to exist globally at depths between 60‒150 km and as determined by passive seismic studies. Our results show that beneath the Malawi Rift, there is no pattern of N-S elongated crustal thinning following the surface expression of the Malawi Rift. With the exception of a north-central region of crustal thinning (< 35 km), most of the southern part of the rift is underlain by thick crust (~40‒44 km). Different from the Moho, the MLD is shallower beneath the axis of the Malawi Rift forming a N-S trending zone with depths of 64‒80 km, showing a broad and gentle topography. We interpret the MLD as representing a sharp density contrast resulting from metasomatized lithosphere due to lateral migration along mobile belts of hot mantle melt or fluids from a distant plume and not from an ascending asthenosphere. These fluids weaken the lithosphere enhancing rift nucleation. The availability of satellite gravity worldwide makes gravity a promising technique for determining the MLD globally.

  11. Shallow afterslip following the Mw 7.2 October 23, 2011 Van earthquake (Turkey) deduced from GPS observations

    NASA Astrophysics Data System (ADS)

    Dogan, U.; Demir, D. O.; Cakir, Z.; Ergintav, S.; Ozener, H.; Reilinger, R. E.

    2013-12-01

    The 23 October 2011 (Mw 7.2) Van earthquake is among the largest events to occur over the last 35 years in eastern Turkey, part of the Turkish-Iranian plateau where the Arabia-Eurasia plate convergence is accommodated by distributed deformation along thrust and strike slip faults. Focal mechanism solutions and field observations reveal that the earthquake took place on an unmapped, ENE-WSW trending, NNW dipping reverse fault located just 10 km north of Van city. Here, we present our modeling results of GPS measurements that provide constraints on the mechanism of the postseismic deformation of the earthquake. The postseismic surface deformation field between November 2011 and September 2012 is derived from continuous GPS stations in the far field and survey-type GPS measurements carried out in a GPS network we established after the earthquake in the near field. Decreasing logarithmically with time, the GPS displacements near the surface rupture accumulate to a maximum of 28.5 × 0.1 cm in horizontal direction (heading to SW) within a year following the earthquake. Analysis of co- and post-seismic GPS displacements reveals that a splay from the coseismic fault on the footwall block has been reactivated aseismically following the earthquake. We model the GPS measurements using dislocations on triangular planes in a homogenous and elastic half space. Two fault models were constructed; one fault represents the coseismic rupture (i.e., Van fault) constrained by InSAR and field observations, and the other represents the splay beneath the main fault that merge at a depth of ~5 km. Inversions of aseismic slip on the both faults indicate that the postseismic deformation can be adequately explained by shallow afterslip above the high coseismic slip patch centered around 15 km of depth on the fault, suggesting that the afterslip is driven most likely by coseismic stress changes. The cumulative aseismic moment due to postseismic afterslip is 7.518 N m (equivalent of Mw = 6.5) or 12 % of the mainshock moment release (compared to USSG body-wave MTS). Modeling predicts aseismic thrust slip with a significant left- and right-lateral component that reaches to 40 cm. Therefore, the slip deficit on the shallow section of the coseismic fault predicted by InSAR based models is filled by significant amount of aseismic slip, which may suggest that the potential for a large earthquake on the shallow section of the Van fault may have been considerably reduced by postseismic afterslip. Keywords: 2011 Van earthquake, GPS, postseismic deformation, afterslip, elastic dislocation

  12. Culinary herbs and spices: their bioactive properties, the contribution of polyphenols and the challenges in deducing their true health benefits.

    PubMed

    Opara, Elizabeth I; Chohan, Magali

    2014-01-01

    Herbs and spices have been used for both culinary and medicinal purposes for centuries. Over the last decade, research into their role as contributors of dietary polyphenols, known to possess a number of properties associated with reducing the risk of developing chronic non-communicable diseases, has increased. However, bearing in mind how these foods are consumed, normally in small quantities and in combination with other foods, it is unclear what their true benefit is from a health perspective. The aim of this review is to use the literature to discuss how preparative and digestive processes, bioavailability and interactions between foods may influence the bioactive properties of these foods, and whether or not polyphenols are responsible for these properties. Furthermore, this review aims to highlight the challenges that need to be addressed so as to determine the true benefits of these foods and the mechanisms of action that underpin their purported efficacy. PMID:25340982

  13. Surface processes on the asteroid deduced from the external 3D shapes and surface features of Itokawa particles

    NASA Astrophysics Data System (ADS)

    Tsuchiyama, A.; Matsumoto, T.

    2015-10-01

    Particles on the surface of S-type Asteroid 25143 Itokawa were successfully recovered by the Hayabusa mission of JAXA (e.g., [1,2]). They are not only the first samples recovered from an asteroid, but also the second extraterrestrial regolith to have been sampled, the first being the Moon by Apollo and Luna missions. The analysis of tiny sample particles (20-200 μm) shows that the Itokawa surface material is consistent with LL chondrites suffered by space weathering as expected and brought an end to the origin of meteorites (e.g., [2-4]). In addition, the examination of Itokawa particles allow studies of surface processes on the asteroid because regolith particles can be regarded as an interface with the space environment, where the impacts of small objects and irradiation by the solar wind and galactic cosmic rays should have been recorded. External 3D shapes and surface features of Itokawa regolith particles were examined. Two kinds of surface modification, formation of space-weathering rims mainly by solar wind implantation and surface abrasion by grain migration, were recognized. Spectral change of the asteroid proceeded by formation of space-weathering rims and refreshment of the regolith surfaces. External 3D shapes and surface morphologies of the regolith particles can provide information about formation and evolution history of regolith particles in relation to asteroidal surface processes. 3D shapes of Itokawa regolith particles were obtained using microtomography [3]. The surface nanomiromorpholgy of Itokawa particles were also observed using FE-SEM [5]. However, the number of particles was limited and genial feature on the surface morphology has not been understood. In this study, the surface morphology of Itokawa regolith particles was systematically investigated together with their 3D structures.

  14. The Determination of Earthquake Hazard Parameters Deduced from Bayesian Approach for Different Seismic Source Regions of Western Anatolia

    NASA Astrophysics Data System (ADS)

    Bayrak, Yusuf; Türker, Tuğba

    2016-01-01

    The Bayesian method is used to evaluate earthquake hazard parameters of maximum regional magnitude ( M max), β value, and seismic activity rate or intensity ( λ) and their uncertainties for the 15 different source regions in Western Anatolia. A compiled earthquake catalog that is homogenous for M s ≥ 4 was completed during the period from 1900 to 2013. The computed M max values are between 6.00 and 8.06. Low values are found in the northern part of Western Anatolia, whereas high values are observed in the southern part of Western Anatolia, related to the Aegean subduction zone. The largest value is computed in region 10, comprising the Aegean Islands. The quantiles of functions of distributions of true and apparent magnitude on a given time interval [0 ,T] are evaluated. The quantiles of functions of distributions of apparent and true magnitudes for future time intervals of 5, 10, 20, 50, and 100 years are calculated in all seismogenic source regions for confidence limits of probability levels of 50, 70, and 90 %. According to the computed earthquake hazard parameters, the requirement leads to the earthquake estimation of the parameters referred to as the most seismically active regions of Western Anatolia. The Aegean Islands, which have the highest earthquake magnitude (7.65) in the next 100 years with a 90 % probability level, is the most dangerous region compared to other regions. The results found in this study can be used in probabilistic seismic hazard studies of Western Anatolia.

  15. Ore formation at the Kupol epithermal gold-silver deposit in northeastern Russia deduced from fluid inclusion study

    NASA Astrophysics Data System (ADS)

    Volkov, A. V.; Prokof'ev, V. Yu.; Savva, N. E.; Sidorov, A. A.; Bayankin, M. A.; Uyutnov, K. V.; Kolova, E. E.

    2012-07-01

    The Kupol epithermal gold-silver deposit-the largest of this type of mineralization in northeastern Russia-is situated in the outer zone of the Okhotsk-Chukotka volcanic belt. The results of thermobarogeochemical study of fluid inclusions in quartz from ore veins at the Kupol deposit are compared with the data on the Dvoinoi and Arykvaam deposits. The study of aqueous extracts from fluid inclusions revealed that the chemical compositions of ore-forming fluids at the Dvoinoi and Kupol deposits are similar in most elements. The only substantial difference is that fluids from the Kupol deposit are considerably enriched in sulfate, as is characteristic of the alunite-subtype of epithermal high-sulfidation mineralization. The salinity of aqueous solutions filling inclusions in amethyst and quartz from ore veins at the Kupol and Dvoinoi deposits is two-three times higher than the salinity of fluid inclusions from the barren veins at the Arykvaam occurrence. The data obtained support the hypothesis put forward earlier that fumaroles and solfataras played a part in ore deposition at the Kupol deposit.

  16. Millennial-scale Variation in East Asian Summer Monsoon Front Position Deduced from Provenance Changes in Yangtze River Delta Sediments

    NASA Astrophysics Data System (ADS)

    Tada, R.; Ke, W.; Saito, K.; Zheng, H.; Irino, T.; Chao, L.; He, M.; Sugisaki, S.; Kuboki, Y.; Suzuki, Y.; Uchida, M.

    2014-12-01

    Spatio-temporal variability of East Asian summer monsoon (EASM) precipitation on millennial timescale during the Holocene is of major interest to climatologists. Recent studies on the variability of EASM precipitation during the Holocene focus on its high resolution reconstruction using stalagmite's δ18O record. However, stalagmite's δ18O does not necessarily reflect EASM precipitation intensity and information on spatial precipitation pattern is difficult to obtain.Yangtze River drainage occupies major part of South China and lies oblique to EASM front direction. Consequently, when EASM front penetrated deep(shallow) into China, more precipitation occurred in the upper(lower) reaches. Because over 96% of the sediment discharge from Yangtze is transported as suspension, it is possible to estimate relative contribution of precipitation between the lower and upper reaches from the provenance of suspended particles.Here we use ESR intensity of quartz in fine silt fraction from Yangtze River Delta core to detect changes in heavy precipitation area within Yangtze River drainage. ESR intensity reflects the average age of source rocks. Since Mesozoic rocks are widely exposed in the upper reaches whereas Proterozoic rocks are exposed in the lower reaches, it is possible to detect relative contribution of suspended sediments from the upper vs. lower reaches. Our study on ESR intensity on modern Yangtze River sediments suggests that we can distinguish the suspended sediments from the upper vs. lower reaches, and that their mixing ratio reflects the relative ratio of the water from the two areas. We will present the result and demonstrate its implication.

  17. 3-D Structure of Arcade Type Flares Deduced from Soft X-Ray Observations of a Homologous Flare Series

    NASA Astrophysics Data System (ADS)

    Morita, S.; Uchida, Y.; Hirose, S.

    2002-01-01

    In the solar flare problems, no ultimate model that matches observations has been established. One of the reasons for this is due to the restrictions in the observational data lacking information about the third dimension. Thus, many researchers have tried to get information about the three dimensional (3-D) coronal structures by using various techniques or ideas; like movie analysis, calculations using vector or line-of-sight components of photospheric magnetic data, and etc.. In the near future, a mission named STEREO which will obtain information about the 3-D coronal structures from two satellites, is planned. In the present paper, we noted the homology in a homologous flare series of February 1992. We derived a 3-D coronal structures by making use of the images obtained from the three different sight-lines at some common phases in them with Yohkoh SXT. The result of this analysis has made it clear that the so-called ``cusped arcade'' at the maximum phase in the well-known 1992 February 21 flare is, contrary to the general views, an ``elongated arch'' seen with a shallow oblique angle. It is not the ``flare arcade'' seen axis-on as widely conceived. This elongated arch coincides roughly with a diagonal of the main body of the "soft X-ray arcade" that came up later. The magnetic structure causing the flare as a whole turned out in this analysis to be a structure with quadruple magnetic sources. The relative locations of these four characteristic sources stayed almost the same throughout the period of this homologous flare series, determining the fundamental shape of this homologous series. We also examined the corresponding features for other similar events, also using information from other satellites, and will report the results.

  18. Mantle flow deduced from geochemical variations in alkaline magmas of HIMU affinity from continent to ocean, northwestern Ross Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Castillo, P. R.; Panter, K. S.; McIntosh, W. C.

    2011-12-01

    Cenozoic alkaline magmatism in the northwestern Ross Sea (NWRS) region has been recently expanded to include numerous volcanic seamounts on the continental shelf and hundreds more located within the oceanic Adare Basin [1]. The seamounts are Pliocene in age and petrogenetically akin to volcanism on land in the West Antarctic rift system. In general, trace element and Sr-Nd-Pb isotopic data resemble those from ocean islands with HIMU affinity. Apart from the well studied Cameroon volcanic line in West Africa, the NWRS is a unique setting for comparing contemporary alkaline volcanism bridging the transition from oceanic to thinned continental lithosphere adjacent to the thick East Antarctic craton. The geochemistry of NWRS basalts, extending to the northeast from the Mariner Glacier to the Adare Peninsula and into the Adare Basin (~168°E 73°S to ~173°E 70°S), shows a remarkable orderly increase in degree of silica-undersaturation, P2O5, Nb, Zr, Sr contents and La/Yb, Nb/Y, 143Nd/144Nd and 206Pb/204Pb ratios, coupled with a decrease in Ba/La and 87Sr/86Sr ratios, suggesting they were generated from a common heterogeneous mantle source at progressively smaller melt fractions from land to sea. Geochemical variations coincide with northward age propagation in magmatism and southward increase in rifting since the middle Miocene [2]. We propose that the HIMU-like signature in both continental and oceanic sectors is derived from metasomatized lithosphere, whereby the most easily fusible components contribute to the smaller degree melts in greater proportions ocean-ward. Melting may have been triggered by influx of warm asthenosphere initially beneath the continent and then northward by edge-driven convection and channelized by focused extension [3] into the Adare Basin where the metasomatized source is more dispersed. [1] Panter & Castillo (2008) USGS Open-File Report 2007-1047, 069. [2] Granot et al. (2010) Geochem. Geophys. Geosyst. 11(8). [3] Huerta & Harry (2007) Earth Planet. Sci. Lett. 255.

  19. Interhemispheric differences and solar cycle effects of the high-latitude ionospheric convection patterns deduced from Cluster EDI observations

    NASA Astrophysics Data System (ADS)

    Förster, Matthias; Haaland, Stein

    2015-04-01

    Here, we present a study of ionospheric convection at high latitudes that is based on satellite measurements of the Electron Drift Instrument (EDI) on-board the Cluster satellites, which were obtained over a full solar cycle (2001-2013). The mapped drift measurements are covering both hemispheres and a variety of different solar wind and interplanetary magnetic field (IMF) conditions. The large amount of data allows us to perform more detailed statistical studies. We show that flow patterns and polar cap potentials can differ between the two hemispheres on statistical average for a given IMF orientation. In particular, during southward directed IMF conditions, and thus enhanced energy input from the solar wind, we find that the southern polar cap has a higher cross polar cap potential. We also find persistent north-south asymmetries which cannot be explained by external drivers alone. Much of these asymmetries can probably be explained by significant differences in the strength and configuration of the geomagnetic field between the Northern and Southern Hemisphere. Since the ionosphere is magnetically connected to the magnetosphere, this difference will also be reflected in the magnetosphere in the form of different feedback from the two hemispheres. Consequently, local ionospheric conditions and the geomagnetic field configuration are important for north-south asymmetries in large regions of geospace. The average convection is higher during periods with high solar activity. Although local ionospheric conditions may play a role, we mainly attribute this to higher geomagnetic activity due to enhanced solar wind - magnetosphere interactions.

  20. Local and Catchment-Scale Water Storage Changes in Northern Benin Deduced from Gravity Monitoring at Various Time-Scales

    NASA Astrophysics Data System (ADS)

    Hinderer, J.; Hector, B.; Séguis, L.; Descloitres, M.; Cohard, J.; Boy, J.; Calvo, M.; Rosat, S.; Riccardi, U.; Galle, S.

    2013-12-01

    Water storage changes (WSC) are investigated by the mean of gravity monitoring in Djougou, northern Benin, in the frame of the GHYRAF (Gravity and Hydrology in Africa) project. In this area, WSC are 1) part of the control system for evapotranspiration (ET) processes, a key variable of the West-African monsoon cycle and 2) the state variable for resource management, a critical issue in storage-poor hard rock basement contexts such as in northern Benin. We show the advantages of gravity monitoring for analyzing different processes in the water cycle involved at various time and space scales, using the main gravity sensors available today (FG5 absolute gravimeter, superconducting gravimeter -SG- and CG5 micro-gravimeter). The study area is also part of the long-term observing system AMMA-Catch, and thus under intense hydro-meteorological monitoring (rain, soil moisture, water table level, ET ...). Gravity-derived WSC are compared at all frequencies to hydrological data and to hydrological models calibrated on these data. Discrepancies are analyzed to discuss the pros and cons of each approach. Fast gravity changes (a few hours) are significant when rain events occur, and involve different contributions: rainfall itself, runoff, fast subsurface water redistribution, screening effect of the gravimeter building and local topography. We investigate these effects and present the statistical results of a set of rain events recorded with the SG installed in Djougou since July 2010. The intermediate time scale of gravity changes (a few days) is caused by ET and both vertical and horizontal water redistribution. The integrative nature of gravity measurements does not allow to separate these different contributions, and the screening from the shelter reduces our ability to retrieve ET values. Also, atmospheric corrections are critical at such frequencies, and deserve some specific attention. However, a quick analysis of gravity changes following rain events shows that the values are in accordance with expected ET values (up to about 5mm/day). Seasonal WSC are analyzed since 2008 using FG5 absolute gravity measurements four times a year and since 2010 using the continuous SG time series. They can reach up to 12 microGal (≈270mm) and show a clear interannual variability, as can be expected from rainfall variability in the area. This data set allows some estimates of an average specific yield for the local aquifer, together with a scaling factor for Magnetic Resonance Soundings-derived water content.

  1. A new estimate of the chondrule cooling rate deduced from an analysis of compositional zoning of relict olivine

    SciTech Connect

    Miura, H.; Yamamoto, T.

    2014-03-01

    Compositional zoning in chondrule phenocrysts records the crystallization environments in the early solar nebula. We modeled the growth of olivine phenocrysts from a silicate melt and proposed a new fractional crystallization model that provides a relation between the zoning profile and the cooling rate. In our model, we took elemental partitioning at a growing solid-liquid interface and time-dependent solute diffusion in the liquid into consideration. We assumed a local equilibrium condition, namely, that the compositions at the interface are equal to the equilibrium ones at a given temperature. We carried out numerical simulations of the fractional crystallization in one-dimensional planar geometry. The simulations revealed that under a constant cooling rate the growth velocity increases exponentially with time and a linear zoning profile forms in the solid as a result. We derived analytic formulae of the zoning profile, which reproduced the numerical results for wide ranges of crystallization conditions. The formulae provide a useful tool to estimate the cooling rate from the compositional zoning. Applying the formulae to low-FeO relict olivine grains in type II porphyritic chondrules observed by Wasson and Rubin, we estimate the cooling rate to be ∼200-2000 K s{sup –1}, which is greater than that expected from furnace-based experiments by orders of magnitude. Appropriate solar nebula environments for such rapid cooling conditions are discussed.

  2. Details of the evolutionary history from invertebrates to vertebrates, as deduced from the sequences of 18S rDNA.

    PubMed Central

    Wada, H; Satoh, N

    1994-01-01

    Almost the entire sequences of 18S rDNA were determined for two chaetognaths, five echinoderms, a hemichordate, and two urochordates (a larvacean and a salp). Phylogenetic comparisons of the sequences, together with those of other deuterostomes (an ascidian, a cephalochordate, and vertebrates) and protostomes (an arthropod and a mollusc), suggest the monophyly of the deuterostomes, with the exception of the chaetognaths. Chaetognaths may not be a group of deuterostomes. The deuterostome group closest to vertebrates was the group of cephalochordates. Ascidians, larvaceans, and salps seem to form a discrete group (urochordates), in which the early divergence of larvaceans is evident. These results support the hypothesis that chordates evolved from free-living ancestors. PMID:8127885

  3. Chromospheric evaporation flows and density changes deduced from Hinode/EIS during an M1.6 flare

    NASA Astrophysics Data System (ADS)

    Gömöry, P.; Veronig, A. M.; Su, Y.; Temmer, M.; Thalmann, J. K.

    2016-04-01

    Aims: We study the response of the solar atmosphere during a GOES M1.6 flare using spectroscopic and imaging observations. In particular, we examine the evolution of the mass flows and electron density together with the energy input derived from hard X-ray (HXR) in the context of chromospheric evaporation. Methods: We analyzed high-cadence sit-and-stare observations acquired with the Hinode/EIS spectrometer in the Fe xiii 202.044 Å (log T = 6.2) and Fe xvi 262.980 Å (log T = 6.4) spectral lines to derive temporal variations of the line intensity, Doppler shifts, and electron density during the flare. We combined these data with HXR measurements acquired with RHESSI to derive the energy input to the lower atmosphere by flare-accelerated electrons. Results: During the flare impulsive phase, we observe no significant flows in the cooler Fe xiii line but strong upflows, up to 80-150 km s-1, in the hotter Fe xvi line. The largest Doppler shifts observed in the Fe xvi line were co-temporal with the sharp intensity peak. The electron density obtained from a Fe xiii line pair ratio exhibited fast increase (within two minutes) from the pre-flare level of 5.01 × 109 cm-3 to 3.16 × 1010 cm-3 during the flare peak. The nonthermal energy flux density deposited from the coronal acceleration site to the lower atmospheric layers during the flare peak was found to be 1.34 × 1010 erg s-1 cm-2 for a low-energy cut-off that was estimated to be 16 keV. During the decline flare phase, we found a secondary intensity and density peak of lower amplitude that was preceded by upflows of ~15 km s-1 that were detected in both lines. The flare was also accompanied by a filament eruption that was partly captured by the EIS observations. We derived Doppler velocities of 250-300 km s-1 for the upflowing filament material. Conclusions: The spectroscopic results for the flare peak are consistent with the scenario of explosive chromospheric evaporation, although a comparatively low value of the nonthermal energy flux density was determined for this phase of the flare. This outcome is discussed in the context of recent hydrodynamic simulations. It provides observational evidence that the response of the atmospheric plasma strongly depends on the properties of the electron beams responsible for the heating, in particular the steepness of the energy distribution. The secondary peak of line intensity and electron density detected during the decline phase is interpreted as a signature of flare loops being filled by expanding hot material that is due to chromospheric evaporation. A movie is available at http://www.aanda.org

  4. Grand solar minima and maxima deduced from 10Be and 14C: magnetic dynamo configuration and polarity reversal

    NASA Astrophysics Data System (ADS)

    Inceoglu, F.; Simoniello, R.; Knudsen, M. F.; Karoff, C.; Olsen, J.; Turck-Chiéze, S.; Jacobsen, B. H.

    2015-05-01

    Aims: This study aims to improve our understanding of the occurrence and origin of grand solar maxima and minima. Methods: We first investigate the statistics of peaks and dips simultaneously occurring in the solar modulation potentials reconstructed using the Greenland Ice Core Project (GRIP) 10Be and IntCal13 14C records for the overlapping time period spanning between ~1650 AD to 6600 BC. Based on the distribution of these events, we propose a method to identify grand minima and maxima periods. By using waiting time distribution analysis, we investigate the nature of grand minima and maxima periods identified based on the criteria as well as the variance and significance of the Hale cycle during these kinds of events throughout the Holocene epoch. Results: Analysis of grand minima and maxima events occurring simultaneously in the solar modulation potentials, reconstructed based on the 14C and the 10Be records, shows that the majority of events characterized by periods of moderate activity levels tend to last less than 50 years: grand maxima periods do not last longer than 100 years, while grand minima can persist slightly longer. The power and the variance of the 22-year Hale cycle increases during grand maxima and decreases during grand minima, compared to periods characterized by moderate activity levels. Conclusions: We present the first reconstruction of the occurrence of grand solar maxima and minima during the Holocene based on simultaneous changes in records of past solar variability derived from tree-ring 14C and ice-core 10Be, respectively. This robust determination of the occurrence of grand solar minima and maxima periods will enable systematic investigations of the influence of grand solar minima and maxima episodes on Earth's climate.

  5. Calcium translocation mechanism in sarcoplasmic reticulum vesicles, deduced from location studies of protein-bound spin labels.

    PubMed Central

    Champeil, P; Rigaud, J L; Gary-Bobo, C M

    1980-01-01

    Sarcoplasmic reticulum vesicles were exposed to various thiol-directed spin labels, and the position of the label on the inner or outer vesicle surface was investigated as a function of the ATPase (adenosinetriphosphatase; ATP phosphohydrolase, EC 3.6.1.3) chemical state. Previous measurements of label accessibility to externally added ascorbate had been considered to suggest an external-internal transition of protein-bound labels, coupled with ion translocation [Tonomura, Y. & Morales, M.F. (1974) Proc. Natl. Acad. Sci. USA 71, 3687-3691]. We show that these ascorbate studies do not lead to convincing conclusions. We demonstrate, on the contrary, that transition ions (nickel and ferricyanide) can be used as selective line-broadening agents for the signals arising from external labels. No significant difference in nickel- or ferricyanide-label interaction can be attributed to a different orientation of the label in any of the enzyme chemical states tested. Our results therefore contradict the current interpretation of ascorbate quenching experiments in terms of calcium ATPase rotatory motion; rather they are consistent with ion transport models involving only limited conformational rearrangements of the pump. PMID:6446710

  6. Nanocrystalline tin oxide: Possible origin of its weak ferromagnetism deduced from nuclear magnetic resonance and X-ray photoelectron spectroscopies

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Lian, Yadong; Gu, Min; Yu, Ji; Tang, Tong B.; Sun, Jian; Zhang, Weiyi

    2016-09-01

    Nanocrystalline tin oxide was fabricated, with molar ratio O/Sn determined as 1.40, 1.55, 1.79, 1.92 and 1.96 from X-ray photoelectron spectroscopy. They displayed weak ferromagnetism, the sample with O/Sn = 1.55 showing the maximum saturation magnetization reaching almost 8 ×10-3 emu /g at room temperature. 119Sn nuclear magnetic resonance allowed the deduction, based on four resolved resonance peaks, that their Sn ions had four possible coordination numbers, namely 3, 4, 5 and 6. The relative fraction of 4-coordinated cations was the one found to bear positive linear correlation with saturation magnetization of the sample. It is surmised that magnetism in tin oxide results mainly from 4-coordination Sn ions, of valance about +3, as estimated from the binding energies of their 3d photoelectron emission levels.

  7. Pulling Marbles from a Bag: Deducing the Regional Impact History of the SPA Basin from Impact-Melt Rocks

    NASA Technical Reports Server (NTRS)

    Cohen, Barbara A.; Coker, Robert F.

    2010-01-01

    The South Pole Aitken (SPA) basin is the stratigraphically oldest identifiable lunar basin and is therefore one of the most important targets for absolute age-dating to help understand whether ancient lunar bombardment history smoothly declined or was punctuated by a cataclysm. A feasible near-term approach to this problem is to robotically collect a sample from near the center of the basin, where vertical and lateral mixing provided by post-basin impacts ensures that such a sample will be composed of small rock fragments from SPA itself, from local impact craters, and from faraway giant basins. The range of ages, intermediate spikes in the age distribution, and the oldest ages are all part of the definition of the absolute age and impact history recorded within the SPA basin.

  8. Pulling Marbles from a Bag: Deducing the Regional Impact History of the SPA Basin from Impact Melt Rocks

    NASA Technical Reports Server (NTRS)

    Cohen, Barbara A.; Coker, R. F.

    2009-01-01

    The South Pole-Aitken (SPA) basin is an important target for absolute age-dating. Vertical and lateral impact mixing ensures that regolith within SPA will contain rock fragments from SPA itself, local impact craters, and faraway giant basins. About 20% of the regolith at any given site is foreign [1, 2], but much of this material will be cold ejecta, not impact melt. We calculated the fraction of contributed impact melt using scaling laws to estimate the amount and provenance of impact melt, demonstrating that SPA melt is the dominant impact melt rock (>70%) likely to be present. We also constructed a statistical model to illustrate how many randomly-selected impact-melt fragments would need to be dated, and with what accuracy, to confidently reproduce the impact history of a site. A detailed impact history becomes recognizable after a few hundred to a thousand randomly-selected marbles, however, it will be useful to have more information (e.g. compositional, mineralogical, remote sensing) to group fragments. These exercises show that SPA melt has a high probability of being present in a scoop sample and that dating of a few hundred to a thousand impact-melt fragments will yield the impact history of the SPA basin.

  9. Primary structure of bovine pituitary secretory protein I (chromogranin A) deduced from the cDNA sequence

    SciTech Connect

    Ahn, T.G.; Cohn, D.V.; Gorr, S.U.; Ornstein, D.L.; Kashdan, M.A.; Levine, M.A.

    1987-07-01

    Secretory protein I (SP-I), also referred to as chromogranin A, is an acidic glycoprotein that has been found in every tissue of endocrine and neuroendocrine origin examined but never in exocrine or epithelial cells. Its co-storage and co-secretion with peptide hormones and neurotransmitters suggest that it has an important endocrine or secretory function. The authors have isolated cDNA clones from a bovine pituitary lambdagt11 expression library using an antiserum to parathyroid SP-I. The largest clone (SP4B) hybridized to a transcript of 2.1 kilobases in RNA from parathyroid, pituitary, and adrenal medulla. Immunoblots of bacterial lysates derived from SP4B lysognes demonstrated specific antibody binding to an SP4B/..beta..-galactosidase fusion protein (160 kDa) with a cDNA-derived component of 46 kDa. Radioimmunoassay of the bacterial lystates with SP-I antiserum yielded parallel displacement curves of /sup 125/I-labeled SP-I by the SP4B lysate and authentic SP-I. SP4B contains a cDNA of 1614 nucleotides that encodes a 449-amino acid protein (calculated mass, 50 kDa). The nucleotide sequences of the pituitary SP-I cDNA and adrenal medullary SP-I cDNAs are nearly identical. Analysis of genomic DNA suggests that pituitary, adrenal, and parathyroid SP-I are products of the same gene.

  10. Candidate mechanisms underlying atypical progesterone profiles as deduced from parameter perturbations in a mathematical model of the bovine estrous cycle.

    PubMed

    Boer, H M T; Apri, M; Molenaar, J; Stötzel, C; Veerkamp, R; Woelders, H

    2012-07-01

    The complex interplay of physiological factors that underlies fertility in dairy cows was investigated using a mechanistic mathematical model of the dynamics of the bovine estrous cycle. The model simulates the processes of follicle and corpus luteum development and its relations with key hormones that interact to control these processes. Several factors may perturb the regular oscillatory behavior of a normal estrous cycle, and such perturbations are likely the effect of simultaneous changes in multiple parameters. The objective of this paper was to investigate how multiple parameter perturbation changes the behavior of the estrous cycle model, so as to identify biological mechanisms that could play a role in the development of cystic ovaries. Cystic ovaries are a common reason for reproductive failure in dairy cows, but much about the causes of this disorder remains unknown. We investigated in which region of the parameter space the model predicts a normal cycle, and when a progesterone pattern occurred with delayed ovulation (indicating a cystic follicle) or delayed luteolysis (indicating a persistent corpus luteum). Perturbation of the initial values for all parameters simultaneously showed 2 specific parameter configurations leading to delayed ovulation or delayed luteolysis immediately. The most important parameter changes in these 2 configurations involve the regulation of corpus luteum functioning, luteolytic signals, and GnRH synthesis, suggesting that these mechanisms are likely involved in the development of cystic ovaries. In the multidimensional parameter space, areas exist in which the parameter configurations resulted in normal cycles. These areas may be separated by areas in which irregular cycle patterns occurred. These irregular patterns thus mark the transition from one stable (normal) situation to another. Interestingly, within a series, there were some cycles with delayed ovulation and some with delayed luteolysis in these patterns. This could represent a situation of resumption of normal cyclicity (e.g., after parturition). In conclusion, the method of parameter perturbation used in the present study is an effective tool to find parameter configurations that lead to progesterone profiles associated with delayed ovulation and delayed luteolysis. Thereby, the model helps to generate hypotheses regarding the underlying cause of the development of cystic ovaries, which could be investigated in future experiments. PMID:22720939

  11. Formation and geomorphologic history of the Lonar impact crater deduced from in situ cosmogenic 10Be and 26Al

    NASA Astrophysics Data System (ADS)

    Nakamura, Atsunori; Yokoyama, Yusuke; Sekine, Yasuhito; Goto, Kazuhisa; Komatsu, Goro; Kumar, P. Senthil; Matsuzaki, Hiroyuki; Kaneoka, Ichiro; Matsui, Takafumi

    2014-08-01

    Lonar impact crater is one of a few craters on Earth formed directly in basalt, providing a unique opportunity to study an analog for crater degradation processes on Mars. Here we present surface 10Be and 26Al exposure dates in order to determine the age and geomorphic evolution of Lonar crater. Together with a 14C age of preimpact soil, we obtain a crater age of 37.5 ± 5.0 ka, which contrasts with a recently reported and apparently older 40Ar/39Ar age (570 ± 47 ka). This suggests that the 40Ar/39Ar age may have been affected by inherited radiogenic 40Ar (40Ar*inherited) in the impact glass. The spatial distribution of surface exposure ages of Lonar crater differs from that for Barringer crater, indicating Lonar crater rim is actively eroding. Our new chronology provides a unique opportunity to compare the geomorphological history of the two craters, which have similar ages and diameters, but are located in different climate and geologic settings.

  12. Functional groups of sialic acids involved in binding to siglecs (sialoadhesins) deduced from interactions with synthetic analogues.

    PubMed

    Kelm, S; Brossmer, R; Isecke, R; Gross, H J; Strenge, K; Schauer, R

    1998-08-01

    The siglecs, formerly called sialoadhesins, are a family of I-type lectins binding to sialic acids on the cell surface. Five members of this family have been identified: sialoadhesin, myelin-associated glycoprotein (MAG), Schwann cell myelin protein (SMP), CD22 and CD33. We have investigated the relevance of substituents at position C-9 and in the N-acetyl group of N-acetylneuraminic acid, using a series of synthetic sialic-acid analogues either on resialylated human erythrocytes or as free alpha-glycosides in hapten inhibition. All five siglecs require the hydroxy group at C-9 for binding, suggesting hydrogen bonding of this substituent with the binding site. Remarkable differences were found among the proteins in their specificity for modifications of the N-acetyl group. Whereas sialoadhesin, MAG and SMP do not tolerate a hydroxy group as in N-glycolylneuraminic acid, they bind to halogenated acetyl residues. In the case of MAG, N-fluoroacetylneuraminic acid is bound about 17-fold better than N-acetylneuraminic acid. In contrast, human and murine CD22 both show good affinity for N-glycolylneuraminic acid, but only human CD22 bound the halogenated compounds. In conclusion, our data indicate that interactions of the hydroxy group at position 9 and the N-acyl substituent contribute significantly to the binding strength. PMID:9738906

  13. Two-phase Neogene extension of the northwestern Basin and Range deduced from thermochronology of a single sample

    NASA Astrophysics Data System (ADS)

    Colgan, J. P.; Shuster, D. L.; Reiners, P. W.

    2007-12-01

    We use a combination of apatite 4He/3He, (U-Th)/He, and fission-track thermochronology to date slip on the Surprise Valley Fault in northeastern California by analyzing a single granitic boulder from a conglomerate lens near the base of the adjacent Warner Range. Apatite from this sample yielded a fission-track age of 11.6 ± 1.4 Ma and a (U-Th)/He age of 3.12 ± 0.2 Ma. Regional geologic relationships indicate that this sample was buried to a depth of about 3.3 km prior to exhumation during slip on the Surprise Valley Fault. Apatite fission-track data indicate that the sample was fully reset (>120°C) prior to exhumation, which began sometime after 14 Ma. A single aliquot of nine apatite grains was step-heated for 4He/3He analysis; modeling of the resulting 4He distribution indicates cooling from >80°C to ~20°C between 3 and 1 Ma. Internally consistent time-temperature (t-T) solutions to the combined 4He/3He, (U-Th)/He, and fission-track data require two periods of cooling, consistent with non-continuous slip on the Surprise Valley Fault. Early cooling and fault slip took place between 14 and 8 Ma, and was followed by a more recent pulse of cooling at about 3 Ma. This timing is consistent with both local geologic relationships and with the regional timing of faulting along the western margin of the Basin and Range. These data demonstrate the resolving power of combined fission-track, (U-Th)/He, and 4He/3He thermochronometric data to extract high-resolution and ultra low temperature t-T information from a single sample close to the earth's surface.

  14. Amino acid sequence of rabbit kidney neutral endopeptidase 24.11 (enkephalinase) deduced from a complementary DNA.

    PubMed Central

    Devault, A; Lazure, C; Nault, C; Le Moual, H; Seidah, N G; Chrétien, M; Kahn, P; Powell, J; Mallet, J; Beaumont, A

    1987-01-01

    Neutral endopeptidase (EC 3.4.24.11) is a major constituent of kidney brush border membranes. It is also present in the brain where it has been shown to be involved in the inactivation of opioid peptides, methionine- and leucine-enkephalins. For this reason this enzyme is often called 'enkephalinase'. In order to characterize the primary structure of the enzyme, oligonucleotide probes were designed from partial amino acid sequences and used to isolate clones from kidney cDNA libraries. Sequencing of the cDNA inserts revealed the complete primary structure of the enzyme. Neutral endopeptidase consists of 750 amino acids. It contains a short N-terminal cytoplasmic domain (27 amino acids), a single membrane-spanning segment (23 amino acids) and an extracellular domain that comprises most of the protein mass. The comparison of the primary structure of neutral endopeptidase with that of thermolysin, a bacterial Zn-metallopeptidase, indicates that most of the amino acid residues involved in Zn coordination and catalytic activity in thermolysin are found within highly honmologous sequences in neutral endopeptidase. Images Fig. 1. Fig. 3. PMID:2440677

  15. Neutral hydrogen shell structure near Comet P/Halley deduced from Vega-1 and Giotto energetic particle data

    NASA Astrophysics Data System (ADS)

    Verigin, M. I.; McKenna-Lawlor, S.; Richter, A. K.; Szego, K.; Veselovskii, I. S.

    An existing model based on Vega-1 (Tunde-M) and Giotto (EPONA) energetic particle data, representing neutral gas shells expanding about Comet Halley, has been updated by incorporating additional information concerning energetic particles recorded by Tunde-M, and neutral gas measurements recorded aboard the Vega-1 and Vega-2 spacecraft, in the original data set. The modified model reproduces reasonably well the positions of the maxima in the intensity profiles of energetic cometary ions observed along the Vega and Giotto trajectories, and it is estimated that the velocity of gas in the envisioned neutral shells is about 7.3 km/s, i.e., close to the velocity (about 8 km/s) of the slow hydrogen component of cometary neutrals. Detailed arguments are presented to support the suggestion that, at distances of 2-10 x exp 6 km from the comet nucleus, the energetic particles recorded in the quasi-periodic structures identified by the Tunde-M and EPONA instruments were protons.

  16. Paleoenvironmental conditions and strontium isotope stratigraphy in the Paleogene Gafsa Basin (Tunisia) deduced from geochemical analyses of phosphatic fossils

    NASA Astrophysics Data System (ADS)

    Kocsis, László; Ounis, Anouar; Chaabani, Fredj; Salah, Neili Mohamed

    2013-06-01

    Fossil shark teeth and coprolites from three major phosphorite occurrences in the Gafsa Basin (southwestern Tunisia) were investigated for their geochemical compositions to improve local stratigraphy and to better assess paleoenvironmental conditions. 87Sr/86Sr isotope ratios of shark teeth from the Early Maastrichtian El Haria Formation and from the Early Eocene Métlaoui s.s. Formation yielded Sr isotope ages of 68 ± 1 and 47.9 ± 1.3 Ma, respectively, which accord with the expected stratigraphic positions of these sediments. Conversely, shark teeth from the Paleocene-Eocene Chouabine Formation have large variation in Sr isotope ratios even within individual layers. After statistical treatment and then elimination of certain outlier samples, three age-models are proposed and discussed. The most reasonable solution includes three subsequent Sr ages of 61.8 ± 2.2 Ma, 57.2 ± 1.8 and 54.6 ± 1.6 for layer IX, layers VIII-V and layers IV-0, respectively. Three scenarios are discussed for explanation of the presence of the outliers: (1) diagenesis, (2) re-working and (3) locally controlled seawater Sr isotope ratio. The most plausible account for the higher 87Sr/86Sr ratios relative to the global ocean in some fossils is enhanced intrabasinal re-working due to low sea level. Conversely, the sample with lower 87Sr/86Sr than the global seawater may link to diagenesis or to seawater influenced by weathering of Late Cretaceous marine carbonates, which latter is supported by model calculation as well. The ɛNd values of these fossils are very similar to those reported for Paleogene and Late Cretaceous Tethyan seawater and are compatible with the above interpretations. The relatively low oxygen isotope values in shark teeth from the topmost phosphate bed of the Chouabine Formation, together with the Sr isotope results, point toward recovering better connections with the open sea. These δ18O data reflect elevated ambient temperature, which may link to the Early Eocene Climatic Optimum.

  17. Concept model of the formation process of humic acid-kaolin complexes deduced by trichloroethylene sorption experiments and various characterizations.

    PubMed

    Zhu, Xiaojing; He, Jiangtao; Su, Sihui; Zhang, Xiaoliang; Wang, Fei

    2016-05-01

    To explore the interactions between soil organic matter and minerals, humic acid (HA, as organic matter), kaolin (as a mineral component) and Ca(2+) (as metal ions) were used to prepare HA-kaolin and Ca-HA-kaolin complexes. These complexes were used in trichloroethylene (TCE) sorption experiments and various characterizations. Interactions between HA and kaolin during the formation of their complexes were confirmed by the obvious differences between the Qe (experimental sorbed TCE) and Qe_p (predicted sorbed TCE) values of all detected samples. The partition coefficient kd obtained for the different samples indicated that both the organic content (fom) and Ca(2+) could significantly impact the interactions. Based on experimental results and various characterizations, a concept model was developed. In the absence of Ca(2+), HA molecules first patched onto charged sites of kaolin surfaces, filling the pores. Subsequently, as the HA content increased and the first HA layer reached saturation, an outer layer of HA began to form, compressing the inner HA layer. As HA loading continued, the second layer reached saturation, such that an outer-third layer began to form, compressing the inner layers. In the presence of Ca(2+), which not only can promote kaolin self-aggregation but can also boost HA attachment to kaolin, HA molecules were first surrounded by kaolin. Subsequently, first and second layers formed (with inner layer compression) via the same process as described above in the absence of Ca(2+), except that the second layer continued to load rather than reach saturation, within the investigated conditions, because of enhanced HA aggregation caused by Ca(2+). PMID:26933902

  18. Quantification of diagenetic overprint processes deduced from fossil carbonate shells and laboratory-based hydrothermal alteration experiments

    NASA Astrophysics Data System (ADS)

    Griesshaber, Erika; Casella, Laura; Mavromatis, Vasileios; Dietzel, Martin; Immenhauser, Adrian; Schmahl, Wolfgang

    2016-04-01

    Benthic and nektonic marine biogenic carbonate archives represent the foundation of numerous studies aiming at reconstructions of past climate dynamics and environmental change. However, living organisms are not in thermodynamic equilibrium and create local chemical environments where physiologic processes such as biomineralization takes place. After the death of the organism the former physiologic disequilibrium conditions are not sustained any more and all biological tissues are altered by equilibration according to the surrounding environment: diagenesis. With increasing diagenetic alteration, the biogenic structure and fingerprint fades away and is replaced by inorganic features. Thus, recrystallization of organism-specific microstructure is a clear indicator for diagenetic overprint. Microstructural data, which mirror recrystallization, are of great value for interpreting geochemical proxies for paleo-environment reconstruction. Despite more than a century of research dealing with carbonate diagenesis, many of the controlling processes and factors are only understood in a qualitative manner. One of the main issues is that diagenetically altered carbonates are usually present as the product of a complex preceding diagenetic pathway with an unknown number of intermediate steps. In this contribution we present and discuss laboratory based alteration experiments with the aim to investigate time-series data sets in a controlled manner. We conducted hydrothermal alteration experiments with modern Arctica islandica (bivalvia) and Notosaria nigricans (brachiopoda) in order to mimic diagenetic overprint. We explore first the potential of electron backscattered diffraction (EBSD) measurements together with statistical data evaluation as a tool to quantify diagenetic alteration of carbonate skeletons. Subsequently, we compare microstructural patterns obtained from experimentally altered shell material with those of fossil specimens that have undergone variable degrees of diagenetic overprint. We intend to come up with a process-oriented understanding of alteration parameters and products as the change in microstructure, texture and mineral phase needs a careful action when it comes to the interpretation of paleoclimate reconstruction data.

  19. Primary structure of the human melanoma-associated antigen p97 (melanotransferrin) deduced from the mRNA sequence.

    PubMed Central

    Rose, T M; Plowman, G D; Teplow, D B; Dreyer, W J; Hellström, K E; Brown, J P

    1986-01-01

    p97 is a cell-surface glycoprotein that is present in most human melanomas but only in trace amounts in normal adult tissues. To determine the structure of this tumor-associated antigen and to identify its functional domains, we have purified and cloned p97 mRNA and determined its nucleotide sequence. The mRNA encodes a 738-residue precursor, which contains the previously determined N-terminal amino acid sequence of p97. After removal of a 19-residue signal peptide, the mature p97 molecule comprises extracellular domains of 342 and 352 residues and a C-terminal 25-residue stretch of predominantly uncharged and hydrophobic amino acids, which we believe acts as a membrane anchor. Each extracellular domain contains 14 cysteine residues, which form seven intradomain disulfide bridges, and one or two potential N-glycosylation sites. Protease digestion studies show that the three major antigenic determinants of p97 are present on the N-terminal domain. The domains are strikingly homologous to each other (46% amino acid sequence homology) and to the corresponding domains of human serum transferrin (39% homology). Conservation of disulfide bridges and of amino acids thought to compose the iron binding pockets suggests that p97 is also related to transferrin in tertiary structure and function. We propose that p97 be renamed melanotransferrin to denote its original identification in melanoma cells and its evolutionary relationship to serotransferrin and lactotransferrin, the other members of the transferrin superfamily. Images PMID:2419904

  20. Towards Evidence-Based Policy for Canadian Education = Vers des politiques candiennes d'education fondees sur la recherche.

    ERIC Educational Resources Information Center

    De Broucker, Patrice, Ed.; Sweetman, Arthur, Ed.

    This book is a collection of 19 essays that broadly treat the use of evidence in informing educational policy and practice in Canada: (1) "Knowledge and Action in Educational Policy and Politics" (Benjamin Levin); (2) "Data, Data Everywhere (and We Don't Know What to Do): Using Data for Wise Decisions in Schools" (Lorna M. Earl); (3) "Do Education…

  1. Two millennia of forest history deduced from closed depressions in the Lorrain plain (North-eastern, France)

    NASA Astrophysics Data System (ADS)

    Etienne, David; Ruffaldi, Pascale; Ritz, Frederic; Dupouey, Jean Luc; Dambrine, Etienne

    2010-05-01

    Recent archaeological surveys and ecological investigations in large "ancient" forests have shown that these areas had been often cultivated during the Roman or Medieval periods, and that this former land use is still deeply influencing present soil properties and plant biodiversity. This new perspective has boosted the research for sediment archives describing the state of forests across the archaeological and historical periods, especially in low altitude forest. Closed depressions (CD) or small hollows (over 30 000 CDs) are found in many silty plains of North-Western Europe (north-eastern France, Luxemburg and Belgium). They are defined as small (100 to 400 m²) closed wetlands, mostly supplied by rainwater. Their origin is debated. Recent coring campaigns in CDs of Lorraine (north-eastern France), 3 to 5 meters thick sediment cores were retrieved. It opened the way for palynological and pedological reconstruction of former landscapes. Here we present a sediment analysis of four peaty CDs (Assenoncourt, Römersberg, Sarrebourg and St Jean), located in different low altitude beech (Fagus) and oak (Quercus) forests, on silty clay soils, 50km from Nancy. As the oldest available map (Naudins, dated from 1728 to 1739) indicated forest boundaries similar to the present ones, these forests were considered as ancient forests. The sedimentation begins during the second Iron Age or Roman period. By this time, pollen analyses show an open landscape (70% of Non Arboreal Pollen), composed mostly by grassland (Plantago major/media, Poaceae and Asteraceae) and cropland (Cerealia-type, Centaurea cyanus). Around the 5th century AD, coinciding with the collapse of the Roman Empire, the pollen sequences describe rapid afforestation by Betula and Corylus, and later Carpinus forest. From the 8th century AD, Carpinus decreases in favour of Quercus which may reflect an anthropogenic clearing. From the 10th to the 14th century AD, croplands expand again with cultivation of hemp (Cannabis-type) and rye (Secale-type). From the 15th to the 19th century AD, pollen diagrams are similar at three sites and differ from the fourth. At Assenoncourt, St Jean and Römersberg, the contribution of Quercus, Carpinus and Fagus remains almost constant: 40%, 10% and 10%. This pattern may be related to short rotation forestry management applied in order to provide fuel wood to the local salt industry. At the fourth site (Sarrebourg), pollen assemblage varies with successive Quercus and Carpinus phases, following a natural sylvicultural evolution. Finally, the present-day forest extension took place during the 19th century with the replacement of wood by coal in the salt industry and the recent collapse of this salt industry during the 20th century. This study confirms, in the context of low altitude forests with heavy soils, what had been observed on shallow calcareous soils of the Lorrain plateau. Most of our state forests, that were thought to be "very ancient" or "immemorial" forest, have been managed for agriculture in the deep past. Because agriculture lands were often limed, fertilized, and eroded, this former agriculture use may to a large extent explain present soil properties and, as a consequence, present biodiversity.

  2. WBN-1 Cycle 10 TPBAR Tritium Release, Deduced From Analysis of RCS Data TTP-1-3046-00, Rev 0

    SciTech Connect

    Shaver, Mark W.; Niehus, Mark T.; Love, Edward F.

    2012-02-19

    This document contains the calculation of the TPBAR tritium release from the Mark 9.2 design TPBARs irradiated in WBN cycle 10. The calculation utilizes the generalized cycle analysis methodology given in TTP-1-3045 Rev. 0.

  3. 15 years slow deformation in and around Lake Vänern (SW Sweden) deduced from repeated GPS measurements

    NASA Astrophysics Data System (ADS)

    Nilfouroushan, Faramarz; Hodacs, Peter; Talbot, Christopher; Koyi, Hemin; Sjöberg, Lars

    2013-04-01

    In this contribution, we present the new geodetic velocity and strain rate fields obtained from GPS surveys around Lake Vänern in southwestern Sweden during the period 1997-2012. The lake Vänern is a graben bounded to the east and west by main N-S striking faults, whereas ENE-WSW striking faults define its northern and southern boundaries. The Värmland GPS network, was setup to monitor the ongoing slow deformation in and around this lake due to tectonic and Glacial Isostatic Adjustment (GIA) processes in Fennoscandia. This network straddles the Protogine and the Mylonite zones and covers one of the most active seismic zones of Sweden. We use GAMIT-GLOBK software to process the past GPS data, collected in October 1997, and the new GPS data, collected in October 2010, 2011 and 2012. We also integrate our local network with the SWEPOS (Swedish Permanent GPS network) and IGS (International GNSS Service) stations to better constrain the velocity fields in ITRF2008 and Eurasia-fixed reference frames. The preliminary results obtained from campaign-mode measurements between 1997 and 2011 shows that the eastern part of the network, located on the eastern side of the NS trending Mylonite zone, is deforming relatively faster than the western part. In the eastern part, the overall extensional components trending NW-SE with local variations are observed. To constrain better these preliminary results, we will add the new campaign data collected in October 2012 to the 1997-2011 solutions and present new deformation maps. The 15 years long observation period (1997-2012) can better constrain sub-mm/yr horizontal crustal shortening or extension rates in Sweden, more specifically around Lake Vänern.

  4. Structural and Temporal Requirements for Geomagnetic Field Reversal Deduced From 40Ar/39Ar Dated Lava Flows

    NASA Astrophysics Data System (ADS)

    Singer, B. S.; Hoffman, K. A.; Coe, R. S.; Brown, L. L.; Jicha, B. R.; Pringle, M. S.; Chauvin, A.

    2004-12-01

    40Ar/39Ar dating of lavas on Tahiti, long thought to record the primary part of the Matuyama-Bruhnes (M-B) reversa1, gives an age of 795+/- 7 ka, indistinguishable from that of transitional lavas in Chile and La Palma, but older than the accepted age for the reversal. Only the transitional lavas on Maui and one from La Palma (dated at 776 +/- 2 ka), agree with the astronomical age for the M-B reversal. Virtual geomagnetic poles (VGPs) associated with the Tahitian and Chilean lavas cluster near Australia, as do VGPs recorded on Tahiti during the Big Lost and Punaruu events, two apparently unsuccessful reversals. These findings, suggestive of a recurring, mantle-held flux pattern at the outer core surface during reversal attempts, are also theoretically equivalent to the situation that would arise today if the axial dipole were to continue to weaken and vanish. Hence, we propose that the 795 ka lavas record the onset of a dynamo process--one which only on occasion would result in polarity change. This initial instability, associated with the first of two decreases in field intensity, began 18 kyrs prior to the actual polarity switch. These data may provide the first observational support to the claim that complete reversals require a significant interval of time for magnetic flux to escape from the solid inner core and sufficiently weaken its stabilizing effect.

  5. The latitudinal dependence of the solar ionization rate as deduced from the Prognoz-6 Lyman-alpha measurements

    NASA Astrophysics Data System (ADS)

    Summanen, T.; Kyrola, E.; Lallement, R.; Bertaux, J. L.

    The latitudinal dependence of the solar ionization is studied using the Lyman-alpha measurements by the Prognoz-6 spacecraft during the solar minimum 1976-77. Applying a hot model for the interplanetary H-gas we have searched for an optimal ionization function to comply with the measurements. Using the optimal ionization function we have studied the latitudinal variation of the solar wind mass flux and the proton density.

  6. Hole size distributions in cardo-based polymer membranes deduced from the lifetimes of ortho-positronium

    NASA Astrophysics Data System (ADS)

    Kobayashi, Y.; Kinomura, A.; Kazama, S.; Inoue, K.; Toyama, T.; Nagai, Y.; Haraya, K.; Mohamed, H. F. M.; O'Rourke, B. E.; Oshima, N.; Suzuki, R.

    2016-01-01

    To clarify the free volume size distributions of the cardo-based polymer membranes, where ortho-positronium (o-Ps) undergoes pick-off annihilation, the o-Ps lifetime distributions were analyzed by the LT9 programme. It was found that the cardo-based polysulfone membrane has much narrower o-Ps lifetime/hole size distributions than the cardo-based polyimide membranes with the 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) moiety. Further, the lifetime/hole size distributions of the cardo-based polymer membranes are appreciably broadened with increasing temperature. This suggests that in these membranes there are holes not only of different sizes but also of different thermal expansion coefficients. It is also shown that in a membrane with a wider hole size distribution the average o-Ps lifetime tends to be longer than would be expected from the correlation between the o-Ps lifetime and the total free volume for common polymers.

  7. The effect of salinization and freshening events in coastal aquifers on nutrient characteristics as deduced from field data

    NASA Astrophysics Data System (ADS)

    Russak, A.; Yechieli, Y.; Herut, B.; Lazar, B.; Sivan, O.

    2015-10-01

    The effect of seawater intrusion and freshening events in coastal aquifers on nutrient (dissolved inorganic nitrogen species, phosphate and silica) dynamics across the fresh-saline groundwater interface (FSI) were quantified using field data. Seasonal vertical profiles revealed a clear transition between nutrient species across the FSI, which is also an oxycline. In view of the results of our experimental simulations, it is clear that the major process controlling the nutrient dynamics at the FSI, besides the mixing that takes place between the two different water bodies, is the seasonal variation between seawater intrusion (salinization) in summer and flushing of the aquifer (freshening) in winter. Aquifer salinization during the summer shifts the FSI and the anaerobic depth-location upwards and leads to the enrichment of NH4+, PO43- and DSi (dissolved silica) in the saline groundwater. NH4+ and PO43- are enriched due to ion exchange, and DSi is enriched either by ion exchange (as PO43-) or as a result of dissolution of biogenic silica. Denitrification occurs at the base of the FSI, as indicated by the slight NO3- depletion and the enrichment in δ15N of NO3-. Aquifer freshening during the winter shifts the FSI downward and the water becomes suboxic with the influence of the oxic fresh groundwater. This leads to nitrification of the NH4+, enrichment of NO2- and depletion of 15N in the residual NO3- in the FSI. These cyclic processes generate a certain depletion of N and enrichment of P in the saline groundwater. Circulation of the saline groundwater below the FSI back to the sea can serve as a partial counterbalance to the high anthropogenic load of N impacting the coastal groundwater system.

  8. Deducing the depth of origin of granulite xenoliths from zircon-rutile thermometry: a case study from Tanzania

    NASA Astrophysics Data System (ADS)

    Aeiker, D. M.; Mansur, A. T.; Rudnick, R. L.; Picolli, P.; McDonough, W. F.

    2006-05-01

    We have applied the zircon-rutile geothermometer of Watson et al. (2006) to granulite-facies xenoliths and high-grade surface metamorphic rocks from the Mozambique Fold Belt (MFB), Tanzania, in order to determine whether the xenoliths derive from the present-day lower crust or from near-surface granulite terranes. Diffusion of Ti in zircon is expected to be exceedingly slow and reflect the temperature at which the zircons grew. In contrast, Zr diffuses relatively rapidly in rutile, and, as cooling rates decrease, the blocking temperature of rutile systematically decreases. Thus, in granulites that experienced very slow cooling (such as those in the present-day lower crust), Zr-in-rutile temperatures should be significantly lower than the temperatures recorded by coexisting zircons. In contrast, granulite-facies rocks found at or near the surface experienced uplift during the final phase of the orogeny, and may have cooled at a markedly faster rate (5 to 10°C/m.y.). In this case, zircon and rutile are expected to return similar temperatures (i.e., within 30-50°C, assuming a peak T of 800°C). We have measured Zr in rutile using EPMA and Ti in zircon using LA-ICP-MS from three granulite-facies xenoliths carried in rift-related basalts erupted through the MFB (two from the Kisite locality) and on the margin of the Tanzanian craton (one from the Labait locality). The two xenoliths from the MFB show contrasting results: a gt-bio orthogneiss yields zircon temperatures ranging from 780 to 1030°C (mean = 850 ± 30°C, 1 σ), which are significantly higher than those recorded in coexisting rutile (620 to 750°C, mean = 680 ± 23°C). In contrast, a gt-opx mafic granulite from Kisite yields zircon and rutile temperatures that are indistinguishable from each other at 780 ± 30°C; these temperatures are also notably cooler than those from zircon in the gt-bio orthogneiss. It thus appears that the orthogneiss derived from the present-day lower crust (and cooled very slowly from high T), while the gt-opx granulite may derive from a near-surface metamorphic terrane that experienced overall lower metamorphic temperatures, and more rapid cooling. Although no high-grade metamorphic rocks crop out in the vicinity of Kisite, they do occur ~45 km to the east. The sample from the craton margin (Labait locality) is a mafic, gt-opx granulite that yields zircon temperatures ranging from 900 to 1020°C (mean = 940 ± 14). These T's are significantly greater than those returned from coexisting rutile (620 to 785°C, mean = 640 ± 22), suggesting that this xenolith is also a sample of present-day lower crust that formed at very high temperatures and cooled slowly in the lower crust of the Tanzanian craton.

  9. Local fluctuations of ozone from 16 km to 45 km deduced from in situ vertical ozone profile

    NASA Technical Reports Server (NTRS)

    Moreau, G.; Robert, C.

    1994-01-01

    A vertical ozone profile obtained by an in situ ozone sonde from 16 km to 45 km, has allowed to observe local ozone concentration variations. These variations can be observed, thanks to a fast measurement system based on a UV absorption KrF excimer laser beam in a multipass cell. Ozone standard deviation versus altitude calculated from the mean is derived. Ozone variations or fluctuations are correlated with the different dynamic zones of the stratosphere.

  10. Deduced products of C4-dicarboxylate transport regulatory genes of Rhizobium leguminosarum are homologous to nitrogen regulatory gene products.

    PubMed Central

    Ronson, C W; Astwood, P M; Nixon, B T; Ausubel, F M

    1987-01-01

    We have sequenced two genes dctB and dctD required for the activation of the C4-dicarboxylate transport structural gene dctA in free-living Rhizobium leguminosarum. The hydropathic profile of the dctB gene product (DctB) suggested that its N-terminal region may be located in the periplasm and its C-terminal region in the cytoplasm. The C-terminal region of DctB was strongly conserved with similar regions of the products of several regulatory genes that may act as environmental sensors, including ntrB, envZ, virA, phoR, cpxA, and phoM. The N-terminal domains of the products of several regulatory genes thought to be transcriptional activators, including ntrC, ompR, virG, phoB and sfrA. In addition, the central and C-terminal regions of DctD were strongly conserved with the products of ntrC and nifA, transcriptional activators that require the alternate sigma factor rpoN (ntrA) as co-activator. The central region of DctD also contained a potential ATP-binding domain. These results are consistent with recent results that show that rpoN product is required for dctA activation, and suggest that DctB plus DctD-mediated transcriptional activation of dctA may be mechanistically similar to NtrB plus NtrC-mediated activation of glnA in E. coli. PMID:3671068

  11. The radiated energy budget of chromospheric plasma in a major solar flare deduced from multi-wavelength observations

    SciTech Connect

    Milligan, Ryan O.; Mathioudakis, Mihalis; Keenan, Francis P.; Kerr, Graham S.; Hudson, Hugh S.; Fletcher, Lyndsay; Dennis, Brian R.; Allred, Joel C.; Chamberlin, Phillip C.; Ireland, Jack

    2014-10-01

    This paper presents measurements of the energy radiated by the lower solar atmosphere, at optical, UV, and EUV wavelengths, during an X-class solar flare (SOL2011-02-15T01:56) in response to an injection of energy assumed to be in the form of nonthermal electrons. Hard X-ray observations from RHESSI were used to track the evolution of the parameters of the nonthermal electron distribution to reveal the total power contained in flare accelerated electrons. By integrating over the duration of the impulsive phase, the total energy contained in the nonthermal electrons was found to be >2 × 10{sup 31} erg. The response of the lower solar atmosphere was measured in the free-bound EUV continua of H I (Lyman), He I, and He II, plus the emission lines of He II at 304 Å and H I (Lyα) at 1216 Å by SDO/EVE, the UV continua at 1600 Å and 1700 Å by SDO/AIA, and the white light continuum at 4504 Å, 5550 Å, and 6684 Å, along with the Ca II H line at 3968 Å using Hinode/SOT. The summed energy detected by these instruments amounted to ∼3 × 10{sup 30} erg; about 15% of the total nonthermal energy. The Lyα line was found to dominate the measured radiative losses. Parameters of both the driving electron distribution and the resulting chromospheric response are presented in detail to encourage the numerical modeling of flare heating for this event, to determine the depth of the solar atmosphere at which these line and continuum processes originate, and the mechanism(s) responsible for their generation.

  12. Genes 55, alpha gt, 47 and 46 of bacteriophage T4: the genomic organization as deduced by sequence analysis.

    PubMed Central

    Gram, H; Rüger, W

    1985-01-01

    The nucleotide sequence of T4 genes 55, alpha gt, 47 and 46 was determined by a combination of 'classical' procedures and a shotgun approach. Small DNA fragments generated by frequent cleavage with restriction enzymes or by sonication of restriction fragments were cloned in phage M13 vectors and sequenced by the dideoxy method. The positions of the genes were determined by marker rescue between the corresponding T4 amber mutants and the cloned T4 DNA fragments used in the sequencing experiments. The sequence gives an insight into the organization of this 7.1-kb early region of the T4 genome and shows that genetically 'silent' portions within this region are not void of genetic information. PMID:4018026

  13. Postmetamorphic unroofing history deduced from petrology, fluid inclusions, thermochronometry, and thermal modeling: An example from southwestern New England

    SciTech Connect

    Hames, W.E.; Tracy, R.J.; Bodnar, R.J. )

    1989-08-01

    Nonlinear unroofing rates from {approximately}10 to <1 mm/yr following high-pressure Acadian (Devonian) metamorphism have been documented in southwestern New England by using combined petrologic, fluid inclusion, thermochronometric, and thermal modeling techniques. Thermobarometry of pelitic schists from the Rowe-Hawley belt of western Connecticut indicates peak Acadian pressure-temperature conditions of 8.2 kbar and 575C. Densities of CO{sub 2}- and H{sub 2}O-rich fluid inclusions require nearly isothermal decompression followed by more isobaric cooling from these conditions. Comparison of this observed path to those generated by thermal models suggests that decompression was characterized by initial rapid upward en bloc velocity ({approximately}1 cm/yr) of brief duration, followed by much slower unroofing rates ({le}0.3 mm/yr). Published geochronologic ages in this region constrain the rapid uplift to the Middle Devonian, and uplift slowed dramatically by the end of the Devonian. This differential uplift has major implications for interpretation of Devonian igneous activity and sedimentation in southwestern New England.

  14. Bias in MODIS cloud drop effective radius for oceanic water clouds as deduced from optical thickness variability across scattering angles

    NASA Astrophysics Data System (ADS)

    Liang, Lusheng; Di Girolamo, Larry; Sun, Wenbo

    2015-08-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) represents our most advanced system for long-term, global observations of cloud optical depth (τ) and cloud drop effective radius (Re). Here we show that the both zonal means of (1) MODIS-retrieved τ and Re and (2) τ retrieved from the Multi-angle Imaging Spectroradiometer (MISR) using MODIS-retrieved Re as input exhibit a large, local negative bias in the rainbow scattering direction relative to adjacent scattering angles for oceanic water clouds. Using radiative transfer simulations, we demonstrate that these local biases are explained by overestimates in MODIS-retrieved Re. While 3-D factors on the angular variability of τ are evident, we conclude that a Re bias is itself an important contributor to this variability. With 3-D factors present, we show that upper and lower bound estimates on the biases in the three MODIS Re products, namely Re1.6, Re2.1, and Re3.7 retrieved from 1.6, 2.1, and 3.7 µm channels, respectively, are possible from a combination of MISR and MODIS data. The midpoints of the upper and lower bounds in zonal mean biases are estimated to be 3-11 µm for Re2.1 and Re1.6 and 2-7 µm for Re3.7, depending on latitude, with smaller biases at latitudes where more stratiform clouds contribute to the total low cloud cover. Removing the bias from the zonal means reveals that Re1.6, Re2.1, and Re3.7 are more similar with each other compared to their original values. The change in zonal mean of Re as a function of latitude is also very different between original and bias-corrected products. These differences change the interpretation of the vertical and horizontal distribution of Re from the original MODIS product.

  15. Formation age and geomorphologic history of the Lonar impact crater deduced from in- situ cosmogenic 10Be and 26Al

    NASA Astrophysics Data System (ADS)

    Nakamura, A.; Yokoyama, Y.; Sekine, Y.; Goto, K.; Komatsu, G.; Kumar, P.; Matsuzaki, H.; Matsui, T.

    2013-12-01

    Impact cratering is a dominant surface modification process on planetary surfaces. In the inner solar system, the large majority of impacts occur on bodies covered by primitive igneous rocks. However, most of the impacts remaining on Earth surface are on different rock types than that of the inner planet and hence geologic knowledge derived from Earth's surface cannot be translated readily. The Lonar crater is a 1.88-km-diameter crater located on the Deccan basaltic traps in India (ca. 65 Ma), and is one of a few craters on Earth bombarded directly on basaltic lava flows. Thus, the Lonar crater provides a rare opportunity to study impact structures on the basaltic surfaces of other terrestrial planets and the Moon. Since the ages of terrestrial impact structures is a key to understand geomorphological processes after the impact, various dating methods have been applied to the Lonar Crater such as fission track (Storzer and Koeberl, 2004), radiocarbon (Maloof, 2010), thermoluminescence (Sengupta et al., 1997), and 40Ar/39Ar (Jourdan et al., 2011). Yet, a large discrepancy between these methods ranging from ca. 1.79 to 570 ka has been resulted. Here we report surface exposure ages based on in-situ cosmogenic 10Be and 26Al in order to obtain a precise age of the Lonar crater formation as well as to study the geomorphologic evolution. The samples are collected from the topographic highs on the rim of the crater and from the ejecta blanket. Exposure ages together with newly obtained radiocarbon age of pre-impact soil indicate much younger ages than that of obtained from 40Ar/39Ar method. This suggests the potential bias because of inherited 40Ar in impact glass. Systematically young exposure age from the rim samples compared to the samples from the ejecta blanket indicate that the rim of the Lonar crater is being actively eroded. Spatial distributions of geomorphic ages observed from the Lonar creator is not the same as the pattern reported from the well-studied Barringer crater in Arizona (Nishiizumi et al, 1991, Phillips et al., 1991), highlighting the different geomorphologic processes of the two craters due to the different climatic and lithologic settings between the two.

  16. Long-distance HF propagation modes deduced from the simultaneous observation by chirp sounder and ISS-b

    NASA Astrophysics Data System (ADS)

    Ichinose, M.; Fujii, S.; Nozaki, K.; Igi, S.

    1982-06-01

    Chirp oblique sounding data and ionospheric data gathered by the ISS-b satellite were analyzed to characterize the propagation modes between West Germany and Japan. Hourly ionograms were generated from November 1978 to May 1979 using chirp sounder operating in the 4-30 MHz range, and ionospheric conditions were measured each time the ISS-b orbit crossed the circuit. Propagation times were quantified for each frequency step by entering the measured ionosphere parameters into a parabolic model for the F2 layer. Simulations were performed for 3- to 5-hop propagation modes and compared with empirical data, showing that the MOF exceeds a theoretical MUF by 1 MHz.

  17. Direction and timing of uplift propagation in the Peruvian Andes deduced from molecular phylogenetics of highland biotaxa

    NASA Astrophysics Data System (ADS)

    Picard, Damien; Sempere, Thierry; Plantard, Olivier

    2008-07-01

    Physical paleoaltimetric methods are increasingly used to estimate the amount and timing of surface uplift in orogens. Because the rise of mountains creates new ecosystems and triggers evolutionary changes, biological data may also be used to assess the development and timing of regional surface uplift. Here we apply this idea to the Peruvian Andes through a molecular phylogeographic and phylochronologic analysis of Globodera pallida, a potato parasite nematode that requires cool temperatures and thus thrives above 2.0-2.5 km in these tropical highlands. The Peruvian populations of this species exhibit a clear evolutionary pattern with deeper, more ancient lineages occurring in Andean southern Peru and shallower, younger lineages occurring progressively northwards. Genetically diverging G. pallida populations thus progressively colonized highland areas as these were expanding northwards, demonstrating that altitude in the Peruvian Andes was acquired longitudinally from south to north, i.e. in the direction of decreasing orogenic volume. This phylogeographic structure is recognized in other, independent highland biotaxa, and point to the Central Andean Orocline (CAO) as the region where high altitudes first emerged. Moreover, molecular clocks relative to Andean taxa, including the potato-tomato group, consistently estimate that altitudes high enough to induce biotic radiation were first acquired in the Early Miocene. After calibration by geological and biological tie-points and intervals, the phylogeny of G. pallida is used as a molecular clock, which estimates that the 2.0-2.5 km threshold elevation range was reached in the Early Miocene in southernmost Peru, in the Middle and Late Miocene in the Abancay segment (NW southern Peru), and from the latest Miocene in central and northern Peru. Although uncertainties attached to phylochronologic ages are significantly larger than those derived from geochronological methods, these results are fairly consistent with coeval geological phenomena along the Peruvian Andes. They strongly suggest that orogenic volume initially developed in the CAO during most of the Miocene until a breakthrough in the latest Miocene allowed the northward propagation of crustal thickening into central and northern Peru, possibly by ductile crustal flow from the CAO. Such a combined phylogeographic and phylochronologic approach to regional uplift opens perspectives to estimate the direction(s) and timing of acquisition of altitude over other Cenozoic orogens.

  18. Strain of the musculus interosseus medius and its rami extensorii in the horse, deduced from in vivo kinematics.

    PubMed

    Jansen, M O; van Buiten, A; van den Bogert, A J; Schamhardt, H C

    1993-01-01

    The in vivo strains of the musculus interosseus medius (suspensory ligament) and its rami extensorii (extensor branches) in the forelimb of the horse were determined from angular changes of the metacarpophalangeal and the distal interphalangeal joints. For this purpose, regression models were fitted to strains and joint angle combinations measured in in vitro limb loading experiments. The in vivo strains were computed from the kinematics of 8 horses at the walk, the trot and the canter. It was found that the extensor branches were strained about 1.0% at hoof impact, which indicates that they passively extend the interphalangeal joints just prior to impact and prevent flexion of the pastern joint just thereafter. The maximal strain of the suspensory ligament amounted to 3.4% at the walk, 5.6% at the trot and 6.3% at a slow canter. PMID:8379292

  19. Secular crustal deformation and interplate coupling of the Japanese Islands as deduced from continuous GPS array, 1996 2001

    NASA Astrophysics Data System (ADS)

    El-Fiky, Gamal; Kato, Teruyuki

    2006-08-01

    Data from the nation-wide GPS continuous tracking network that has been operated by the Geographical Survey Institute of Japan since April 1996 were used to study crustal deformation in the Japanese Islands. We first extracted site coordinate from daily SINEX files for the period from April 1, 1996 to February 24, 2001. Since raw time series of station coordinates include coseismic and postseismic displacements as well as seasonal variation, we model each time series as a combination of linear and trigonometric functions and jumps for episodic events. Estimated velocities were converted into a kinematic reference frame [Heki, K., 1996. Horizontal and vertical crustal movements from three-dimensional very long baseline interferometry kinematic reference frame: implication for reversal timescale revision. J. Geophys. Res., 101: 3187-3198.] to discuss the crustal deformation relative to the stable interior of the Eurasian plate. A Least-Squares Prediction technique has been used to segregate the signal and noise in horizontal as well as vertical velocities. Estimated horizontal signals (horizontal displacement rates) were then differentiated in space to calculate principal components of strain. Dilatations, maximum shear strains, and principal axes of strain clearly portray tectonic environments of the Japanese Islands. On the other hand, the interseismic vertical deformation field of the Japanese islands is derived for the same GPS data interval. The GPS vertical velocities are combined with 31 year tide gage records to estimate absolute vertical velocity. The results of vertical deformation show that (1) the existence of clear uplift of about 6 mm/yr in Shikoku and Kii Peninsula, whereas pattern of subsidence is observed in the coast of Kyushu district. This might reflect strong coupling between the Philippine Sea plate and overriding plate at the Nankai Trough and weak coupling off Kyushu, (2) no clear vertical deformation pattern exists along the Pacific coast of northeastern Japan. This might be due to the long distance between the plate boundary (Japan trench) and overriding plate where GPS sites are located, (3) significant uplift is observed in the southwestern part of Hokkaido and in northeastern Tohoku along the Japan Sea coast. This is possibly due to the viscoelastic rebound of the 1983 Japan Sea ( Mw 7.7) and the 1993 Hokkaido-Nansei-Oki ( Mw 7.8) earthquakes and/or associated with distributed compression of incipient subduction there. We then estimate the elastic deformation of the Japanese Islands caused by interseismic loading of the Pacific and Philippine Sea subduction plates. The elastic models account for most of the observed horizontal velocity field if the subduction movement of the Philippine Sea Plate is 100% locked and if that of the Pacific Plate is 70% locked. However, the best fit for vertical velocity ranges from 80% to 100% coupling factor in southwestern Japan and only 50% in northeastern Japan. Since horizontal data does not permit the separation of rigid plate motion and interplate coupling because horizontal velocities include both contributions, we used the vertical velocities to discriminate between them. So, we can say there is strong interplate coupling (80%-100%) over the Nankaido subduction zone, whereas it is about 50% only over the Kurile-Japan trench.

  20. Preliminary crustal deformation model deduced from GPS and earthquakes’ data at Abu-Dabbab area, Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Mohamed, Abdel-Monem S.; Hosny, A.; Abou-Aly, N.; Saleh, M.; Rayan, A.

    2013-06-01

    A local geodetic network consisting of eleven benchmarks has been established to study the recent crustal deformation in the Abu-Dabbab area. Seven campaigns of GPS measurements have been collected started from October 2008 and ended in March 2012. The collected data were processed using Bernese version 5.0, and the result values were adjusted to get the more accurate positions of the GPS stations. The magnitudes of horizontal displacements are variable from one epoch to another and in the range of 1-3 (±0.2) mm/yr. Due to the differences in rates of the horizontal displacement; the area is divided into two main blocks. The first one, moves to the east direction of about 3 mm/yr, while the second block, moves to the SW direction of about 6 mm/yr. According to the strain fields that were calculated for the different epochs of measurement, the main force is compression force and is taken the NW-SE to NWW-SEE direction. This force could be because of local and regional tectonic processes affecting on the study area. The maximum values of compression stress are found in the southern central and western part of study area. Estimated accumulation of this strain energy may be considered as an indicator of the possibility of earthquake occurrence. From the seismic tomography study, the 3D Vp and Vp/Vs crustal models indicate high Vp/Vs values forms an elongated anomaly, in the central part of the study area, that extends from a depth of 12 km to about 1-2 km of depth is obtained. By using this crustal model in relocations all seismicity informed that most of the seismicity strongly tend to occur in a cluster manner exactly above the southern part of the study area. Based on the conducted source mechanism study, it is noticed that shallow earthquakes are associated by a high CLVD ratio (up to 40%). Furthermore, initiation of a high level seismic activity, without a large seismic main shock is observed in the Abu-Dabbab area. The distribution of micro-earthquakes tends to align in an ENE-WSW direction marking a zone of activity verse the Red Sea. The nucleation of the seismic activity beneath the southern part of the Abu-Dabbab crust is more consistent with the obtained crustal deformation result by increasing the crustal movement in the south part than the northern part. Then, based on the obtained results of the above mentioned studies; seismic tomography; source mechanisms, and crustal deformation we conclude that these seismic activities that are associated by crustal deformation are owing to some magma activity beneath the crust of the Abu-Dabbab area.

  1. LGM and Late Glacial glacier advances in the Cordillera Real and Cochabamba (Bolivia) deduced from 10Be surface exposure dating

    NASA Astrophysics Data System (ADS)

    Zech, R.; Kull, Ch.; Kubik, P. W.; Veit, H.

    2007-06-01

    Surface exposure dating (SED) is an innovative tool being already widely applied for moraine dating and for Late Quaternary glacier and climate reconstruction. Here we present exposure ages of 28 boulders from the Cordillera Real and the Cordillera Cochabamba, Bolivia. Our results indicate that the local Last Glacial Maximum (LGM) in the Eastern Cordilleras occurred at ~22-25 ka and thus synchronous to the global temperature minimum. We were also able to date several Late Glacial moraines to ~11-13 ka, which likely document lower temperatures and increased precipitation ("Coipasa" humid phase). Additionally, we recognize the existence of older Late Glacial moraines re-calculated to ~15 ka from published cosmogenic nuclide data. Those may coincide with the cold Heinrich 1 event in the North Atlantic region and the pronounced "Tauca" humid phase. We conclude that (i) exposure ages in the tropical Andes may have been substantially overestimated so far due to methodological uncertainties, and (ii) although precipitation plays an important role for glacier mass balances in the tropical Andes, it becomes the dominant forcing for glaciation only in the drier and thus more precipitation-sensitive regions further west and south.

  2. LGM and Late Glacial glacier advances in the Cordillera Real and Cochabamba (Bolivia) deduced from 10Be surface exposure dating

    NASA Astrophysics Data System (ADS)

    Zech, R.; Kull, Ch.; Kubik, P. W.; Veit, H.

    2007-10-01

    Surface exposure dating (SED) is an innovative tool already being widely applied for moraine dating and for Late Quaternary glacier and climate reconstruction. Here we present exposure ages of 28 boulders from the Cordillera Real and the Cordillera Cochabamba, Bolivia. Our results indicate that the local Last Glacial Maximum (LGM) in the Eastern Cordilleras occurred at ~22-25 ka and was thus synchronous to the global temperature minimum. We were also able to date several Late Glacial moraines to ~11-13 ka, which likely document lower temperatures and increased precipitation ("Coipasa" humid phase). Additionally, we recognize the existence of older Late Glacial moraines re-calculated to ~15 ka from published cosmogenic nuclide data. Those may coincide with the cold Heinrich 1 event in the North Atlantic region and the pronounced "Tauca" humid phase. We conclude that (i) exposure ages in the tropical Andes may have been overestimated so far due to methodological uncertainties, and (ii) although precipitation plays an important role for glacier mass balances in the tropical Andes, it becomes the dominant forcing for glaciation only in the drier and thus more precipitation-sensitive regions farther west and south.

  3. Matrix genes of measles virus and canine distemper virus: cloning, nucleotide sequences, and deduced amino acid sequences.

    PubMed Central

    Bellini, W J; Englund, G; Richardson, C D; Rozenblatt, S; Lazzarini, R A

    1986-01-01

    The nucleotide sequences encoding the matrix (M) proteins of measles virus (MV) and canine distemper virus (CDV) were determined from cDNA clones containing these genes in their entirety. In both cases, single open reading frames specifying basic proteins of 335 amino acid residues were predicted from the nucleotide sequences. Both viral messages were composed of approximately 1,450 nucleotides and contained 400 nucleotides of presumptive noncoding sequences at their respective 3' ends. MV and CDV M-protein-coding regions were 67% homologous at the nucleotide level and 76% homologous at the amino acid level. Only chance homology was observed in the 400-nucleotide trailer sequences. Comparisons of the M protein sequences of MV and CDV with the sequence reported for Sendai virus (B. M. Blumberg, K. Rose, M. G. Simona, L. Roux, C. Giorgi, and D. Kolakofsky, J. Virol. 52:656-663; Y. Hidaka, T. Kanda, K. Iwasaki, A. Nomoto, T. Shioda, and H. Shibuta, Nucleic Acids Res. 12:7965-7973) indicated the greatest homology among these M proteins in the carboxyterminal third of the molecule. Secondary-structure analyses of this shared region indicated a structurally conserved, hydrophobic sequence which possibly interacted with the lipid bilayer. Images PMID:3754588

  4. Storm-induced changes of the topside ionosphere as deduced from incoherent-scatter radars. Master's thesis

    SciTech Connect

    Lunn, K.J.

    1990-01-01

    Incoherent scatter radar observations from Millstone Hill, Saint Santin, and Arecibo are used to illustrate changes of the topside ionosphere during a geomagnetic storm. These observations consist of electron density, electron and ion temperatures, and ion velocity components parallel and perpendicular to the magnetic field. These parameters can further describe changes in ion composition, electric fields, and neutral winds. Attention is given to a specific storm during the Equinox Transition Study (ETS) of September 1984. In order to isolate the storm effects in the topside ionosphere, a comparison will be made between a disturbed and quiet day. A novel result from this study is the finding of correlated oscillations between parallel and perpendicular ion velocity components which are apparently storm induced. Previously, these oscillations have been observed primarily at night, but now it's noticed that during storm conditions there are prominent oscillations during the day.

  5. Evolution of multicellular animals as deduced from 5S rRNA sequences: a possible early emergence of the Mesozoa.

    PubMed

    Ohama, T; Kumazaki, T; Hori, H; Osawa, S

    1984-06-25

    The nucleotide sequences of 5S rRNA from a mesozoan Dicyema misakiense and three metazoan species, i.e., an acorn-worm Saccoglossus kowalevskii, a moss-animal Bugula neritina, and an octopus Octopus vulgaris have been determined. A phylogenic tree of multicellular animals has been constructed from 73 5S rRNA sequences available at present including those from the above four sequences. The tree suggests that the mesozoan is the most ancient multicellular animal identified so far, its emergence time being almost the same as that of flagellated or ciliated protozoans. The branching points of planarians and nematodes are a little later than that of the mesozoan but are clearly earlier than other metazoan groups including sponges and jellyfishes. Many metazoan groups seem to have diverged within a relatively short period. PMID:6539911

  6. Deducing composition and incident electron spectra from ground-based auroral optical measurements: A study of auroral red line processes

    SciTech Connect

    Meier, R.R. ); Strickland, D.J.; Hecht, J.H.; Christensen, A.B. )

    1989-10-01

    We conclude from a study of the production and loss of O({sup 1}{ital D}) in auroras that the traditional'' sources, direct electron impact excitation of atomic oxygen and dissociative recombination of molecular oxygen ions, can account for most of the O I 6300-A emission rate. In a specific application of the model to the comprehensive observation of an auroral event by Sharp et al. (1979), we show that there is no compelling need for the reaction N({sup 2}{ital D})+O{sub 2}{r arrow}NO+O({sup 1}{ital D}). We also present a study of the sensitivity of the red line emission rate to a wide variety of input conditions. {copyright} American Geophysical Union 1989

  7. Andean uplift and climate evolution in the southern Atacama Desert deduced from geomorphology and supergene alunite-group minerals

    NASA Astrophysics Data System (ADS)

    Bissig, Thomas; Riquelme, Rodrigo

    2010-11-01

    Supergene alunite group minerals from the Late Eocene El Salvador porphyry Cu district, the El Hueso epithermal gold deposit and the Coya porphyry Au prospect located in the Precordillera of Northern Chile (~ 26 to 26° 30´ Lat. S) have been dated by the 40Ar/ 39Ar method and analyzed for stable isotopes. These data support published geomorphologic and sedimentologic evidence suggesting that the Precordillera in the Southern Atacama Desert had been uplifted as early as the late Eocene and, thus, significantly prior to the Altiplano which attained its high elevation only in the late Miocene. The oldest supergene alunite from the Damiana exotic deposit at El Salvador was dated at 35.8 ± 1 Ma and yielded a δD (VSMOW) value of -74‰ which indicates elevations of the Precordillera near El Salvador of at least 3000 m in the Late Eocene. In contrast, Miocene supergene alunite from El Salvador, El Hueso, and Coya have less negative δD signatures reaching values as high as -23 to -25‰ at El Hueso and El Salvador between about 8.2 and 14 Ma. Late Miocene to Holocene supergene alunite, jarosite and natroalunite ages are restricted to El Hueso and Coya located near 4000 m above sea level in the Precordillera, roughly 1000 m higher than the present elevation of El Salvador. The δD values of samples younger than ~ 5 Ma vary between -57 and -97‰. The complex evolution of the δD signatures suggests that meteoric waters recorded in supergene alunite group minerals were variably affected by evaporation and provides evidence for climate desiccation and onset of hyper arid conditions in the Central Depression of the southern Atacama Desert after 15 Ma, which agrees well with published constraints from the Atacama Desert at 23-24° Lat. S. Our data also suggest that wetter climatic conditions than at present prevailed in the latest Miocene and early Pliocene in the Precordillera. The new and previously published age constraints for El Salvador indicate that supergene mineralization at the Damiana exotic Cu deposit occurred periodically over 23 Ma in a locally exceptionally stable paleohydrologic and geomorphologic configuration.

  8. Codon usage, genetic code and phylogeny of Dictyostelium discoideum mitochondrial DNA as deduced from a 7.3-kb region.

    PubMed

    Angata, K; Kuroe, K; Yanagisawa, K; Tanaka, Y

    1995-02-01

    We have sequenced a region (7,376-bp) of the mitochondrial (mt) DNA (54 kb) of the cellular slime mold, Dictyostelium discoideum. From the DNA and amino-acid sequence comparisons with known sequences, genes for ATPase subunit 9 (ATP9), cytochrome b (CYTB), NADH dehydrogenase subunits 1, 3 and 6 (ND1, ND3 and ND6), small subunit rRNA (SSU rRNA) and seven tRNAs (Arg, Asn, Cys, Lys, f-Met, Met and Pro) have been identified. The sequenced region of the mtDNA has a high average A + T-content (70.8%). The A + T-content of protein-genes (73.6%) is considerably higher than that of RNA genes (61.3%). Even with the strong AT-bias, the genetic code employed is most probably the universal one. All seven tRNAs are able to form typical clover leaf structures. The molecular phylogenetic trees of CYTB and SSU rRNA suggest that D. discoideum is closer to green plants than to animals and fungi. PMID:7736610

  9. The characteristic of the magnetopause reconnection X-line deduced from low-altitude satellite observations of cusp ions

    NASA Technical Reports Server (NTRS)

    Lockwood, M.; Onsager, T. G.; Davis, C. J.; Smith, M. F.; Denig, W. F.

    1994-01-01

    We present an analysis of a 'quasi-steady' cusp ion dispersion signature observed at low altitudes. We reconstruct the field-parallel part of the Cowley-D ion distribution function, injected into the open low-latitude boundary layer (LLBL) in the vicinity of the reconnection X-line. From this we find the field parallel magnetosheath flow at the X-line was only 20 +/- 60 km/s, placing the reconnection site close to the flow streamline which is perpendicular to the magnetosheath field. Using interplanetary data and assuming the subsolar magnetopause is in pressure balance, we derive a wealth of information about the X-line, including: the density, flow, magnetic field and Alfven speed of the magnetosheath; the magnetic shear across the X-line; the de-Hoffman Teller speed with which field lines emerge from the X-line; the magnetospheric field; and the ion transmission factor across the magnetopause. The results indicate that some heating takes place near the X-line as the ions cross the magnetopause, and that sheath densities may be reduced in a plasma depletion layer. We also compute the reconnection rate. Despite its quasi-steady appearance on an ion spectrogram, this cusp is found to reveal a large pulse of enhanced reconnection rate.

  10. Location and characteristics of the reconnection X-line deduced from low-altitude satellite and radar observations

    NASA Technical Reports Server (NTRS)

    Lockwood, M.; Davis, C. J.; Smith, M. F.; Onsager, T. G.; Denig, W. F.

    1994-01-01

    We present an analysis of a cusp ion step observed between two poleward-moving events of enhanced ionospheric electron temperature. From the computed variation of the reconnection rate and the onset times of the associated ionospheric events, the distance between the satellite and the X-line can be estimated, but with a large uncertainty due to that in the determination of the low-energy cut-off of the ion velocity distribution function, f(E). Nevertheless, analysis of the time series f(t) shows the reconnection site to be on the dayside magnetopause, consistent with the pulsating cusp model, and the best estimate of the X-line location is 13 R(E) from the satellite. The ion precipitation is used to reconstruct the field-parallel part of the Cowley-D ion distribution function injected into the open low latitude boundary layer (LLBL) in the vicinity of the X-line. From this the Alfven speed, plasma density, magnetic field, parallel ion temperature, and flow velocity of the magnetosheath near the X-line can be derived.

  11. Crust and mantle lithospheric structure of the Iberian Peninsula deduced from potential field modeling and thermal analysis

    NASA Astrophysics Data System (ADS)

    Torne, Montserrat; Fernàndez, Manel; Vergés, Jaume; Ayala, Conxi; Salas, Maria Carolina; Jimenez-Munt, Ivone; Buffett, Grant George; Díaz, Jordi

    2015-11-01

    We investigate the lithospheric structure of the Iberian Peninsula and lateral crustal density variations using a three-step approach. First the crustal and mantle lithosphere thicknesses are calculated from joint geoid and elevation modeling combined with thermal analysis further constrained by seismic data. We then compute the 3D gravity effect of the resulting lithospheric structure to separate the measured Bouguer anomaly into its regional and local components. Finally we invert the residual gravity anomalies to highlight lateral average crustal density variations and discuss them in terms of crustal structures. Our results show that for the majority of the study area the crustal thickness does correlate with the regional topography pattern. The highest topography - above 1500 m - shows thicknesses above 44 km with local values up to 48 km. Crustal thicknesses in the range of 36-40 km are obtained in the uplifted Alpine areas while a thinner crust is observed in sedimentary basins and in the Iberian Massif (30 to 35 km) with the exception of SW Iberia region where the crust thins from 30 to 28 km. Thick lithosphere - above 140 km - is found along the Pyrenees, the Cantabrian Mountains, the Iberian Chain and in the Betics while the thinnest lithosphere is found in SW Iberia (90 km). 3D inversion of residual anomalies show that for the majority of the area the average density of the crust is in the range of 2810 ± 10 kg m- 3. The denser crust is found in the NW and SW regions of the Iberian Massif (+ 30 kg m- 3 on average) and locally in the Pyrenees (above + 70 kg m- 3), NW of the Iberian Chain (+ 15 kg m- 3 on average) and in the southern Internal Betics (+ 70 kg m-3). The least dense crust is found in the central and western Betic Chain (- 30 kg m- 3 on average) and in sedimentary basin depocenters.

  12. Friction weakening in granular flows deduced from seismic records at the Soufrière Hills Volcano, Montserrat

    NASA Astrophysics Data System (ADS)

    Levy, Clara; Mangeney, Anne; Bonilla, Fabian; Hibert, Clément; Calder, Eliza S.; Smith, Patrick J.

    2015-11-01

    Accurate modeling of rockfalls and pyroclastic flows is still an open issue, partly due to a lack of measurements related to their dynamics. Using seismic data from the Soufrière Hills Volcano, Montserrat, and granular flow modeling, we show that the power laws relating the seismic energy Es to the seismic duration ts and relating the loss of potential energy ΔEp to the flow duration tf are very similar, like the power laws observed at Piton de la Fournaise, Reunion Island. Observations showing that tf≃ts suggest a constant ratio Es/ΔEp≃10-5. This similarity in these two power laws can be obtained only when the granular flow model uses a friction coefficient that decreases with the volume transported. Furthermore, with this volume-dependent friction coefficient, the simulated force applied by the flow to the ground correlates well with the seismic energy, highlighting the signature of this friction weakening effect in seismic data.

  13. Friction weakening in granular flows deduced from seismic records at the Soufrière Hills Volcano, Montserrat

    NASA Astrophysics Data System (ADS)

    Levy, Clara; Mangeney, Anne; Bonilla, Fabian; Hibert, Clément; Calder, Eliza; Smith, Paddy

    2015-04-01

    Accurate modelling of rockfalls and pyroclastic flows is still an open issue, partly due the lack of measurements related to the dynamics of such events. Using seismic data from the Soufrière Hills Volcano and granular flow modelling, we show that the power laws relating the seismic energy Es to the seismic duration ts and relating the loss of potential energy ΔEp to the flow duration tf are very similar (Ei ≈ tiβ with i = s,p), as observed previously at Piton de la Fournaise, Reunion Island. Observations showing that tf ≃ ts suggest a constant ratio Es/ΔEp ≃ 10-5. This similarity in the power laws can be obtained only when the granular flow model uses a friction coefficient that decreases with the volume involved. Furthermore, with this volume-dependent friction coefficient, the simulated force applied by the flow to the ground correlates well with the seismic energy, highlighting the signature of this friction weakening effect in seismic data.

  14. Sedimentary cover in the South Western Desert of Egypt as deduced from Bouguer gravity and drill-hole data

    NASA Astrophysics Data System (ADS)

    Senosy, M. M.; Youssef, M. M.; Abdel Zaher, M.

    2013-06-01

    The Western Desert, Egypt includes the major groundwater aquifer in the country. It is apart from the Major Sahara Nubian Aquifer which is present in Sudan, Chad, Egypt and Libya. Thickness of this aquifer is changed laterally from south to north and also from west to east. The changes may structurally or litheologicalley control. The present study is focused on using of Bouguer gravity anomaly mapped at a scale of 1:500,000 and the lithological logs of about 120 deep wells used to determine the thickness of the sedimentary sequence containing the main Nubian sandstone water aquifer in important area of Egypt. The area is located in the southern part of the Western Desert bounded by the latitudes 22°00'-26°30'N, and longitudes 28°30'-33°00'E. The predominant structures affecting the basement rocks and the sedimentary cover were traced and analyzed. The gravity stripping approach was applied to eliminate the gravity effects caused by sedimentary sequence and to separate density anomalies within the sedimentary fill from the influence of rocks at deeper levels in the crystalline crust. The study indicated that the surface of the basement rocks is highly rugged and mostly controlled by structures which have a direct effect on thickness variation of the sedimentary cover all over the area. Regionally the area is characterized by two major intracratonic basins (the Dahkla Basin and the Nile valley Basin) separated by a NE-SW trending swell of the Kharga uplift and bounded at the south by the Oweinat-Bir Safsaf-Aswan uplift. These major tectonic units are controlled by fault structures trending in N-S, E-W, NE-SW, NW-SE, which cut the basement rocks and extend upward in the sedimentary cover. The maximum thickness of sandstone formations is recorded at west Oweinat, west Kurkur, southwest of Aswan, Gramashin, Dakhla oasis and some localities west of Sohag and Qena towns. At these localities the thickness ranges between 600 and 900 m. As this formation is the main water aquifer in the study area, therefore these localities are characterized by the presence of big amount of ground water. Accordingly, these areas must take the priority in the sustainable development programs of southern Egypt.

  15. The structure of the upper crust in the Alps-Apennines boundary region deduced from refraction seismic data

    NASA Astrophysics Data System (ADS)

    Biella, G. C.; Gelati, R.; Maistrello, M.; Mancuso, M.; Massiotta, P.; Scarascia, S.

    1987-10-01

    Analysis of data gathered during the 1983 European Geotraverse southern segment (EGT-S '83) experiments in the region extending from the Emilia-Liguria Apennines to the western Alpine Arc together with data from seismic profiles in the northwestern Apennines accumulated within the framework of the Alps-Apennines Orogene Study Group indicate new details on the structure of the upper crust east and west of the Alps-Apennines boundary. The main results of this analysis centre on two areas. In the Piedmont Tertiary Basin we could determine the depocenter configurations of the 6-7 km thick terrigenous sequence and differentiate the tectonic units in the Piedmont (Alpine) and the Ligurian (Apennine) domains within the basement. In the other area, the Insubric domain underneath the Ligurian nappes of the northern Apennines, we found indications of tectonic doubling within the terrigenous-carbonate sequence in which thrusting attenuates towards the underlying basement, detected at a depth of 12-15 km. In addition, we found that, on a line from the Emilia Apennines to the Monferrato Hills, displacement of the Ligurian nappes over the Insubric domain diminishes to nearly one-third its original extent.

  16. Rupture parameters of the 21 May 2003, Mw 6.8, Zemmouri (Northern Algeria) earthquake deduced from InSAR

    NASA Astrophysics Data System (ADS)

    Belabbes, S.; Wicks, C.; Meghraoui, M.; Cakir, Z.

    2007-12-01

    We study the surface deformation associated with the 21 May, 2003 (Mw=6.8) Zemmouri (Algeria) earthquake, the strongest seismic event felt in the region since 1716. Global and NEIC focal mechanism solutions of the mainshock indicate reverse faulting with a ~N60E trending rupture dipping ~ 45° SE. The earthquake epicenter relocated along the shoreline caused an average 0.50 m coastal uplift along ~50-km-long coastline. We mapped the coseismic surface displacement field caused by the earthquake using the ENVISAT ASAR (IS2) and RADARSAT standard beam (ST5) data. We were able to obtain coseismic interferograms from both the ascending and descending orbits of ENVISAT satellite. The RADARSAT data proved useful only in the descending mode. While the two RADARSAT interferograms cover the entire area of coastal uplift, ENVISAT data cover only the western half of the epicentral zone. Although the InSAR coherence in the epicenter area is poor, deformation fringes are observed along the coast in different patches. In the Boumerdes area, the maximum deformation is indicated by the high gradient of fringes visible in all interferograms in agreement with field measurements (tape, DGPS and leveling). To constrain the earthquake rupture parameters, we model the interferograms and uplift measurements using elastic dislocations on triangular fault patches in an elastic and homogeneous half space. We invert the coseismic slip using a curved surface constructed from triangular elements using Poly3Dinv program that uses a damped least square minimization. The fault rupture is 65-km-long and dips ~40° to the south with a smooth change in strike north of Boumerdes from N 60°-65° to N 95°-105°.

  17. Detailed spatial distribution of microearthquakes beneath the Marmara Sea, Turkey, deduced from long-term ocean bottom observation

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yojiro; Takahashi, Narumi; Pinar, Ali; Kalafat, Doǧan; Citak, Seckin; Comoglu, Mustafa; Polat, Remzi; Çok, Özkan; Ogutcu, Zafer; Suvariklı, Murat; Tunc, Suleyman; Gürbüz, Cemil; Turhan, Fatih; Ozel, Nurcan; Kaneda, Yoshiyuki

    2016-04-01

    The North Anatolian Fault (NAF) crosses the Marmara Sea in E-W direction, accommodating about 25 mm/yr of right-lateral motion between Anatolia and the Eurasian plate. There are many large earthquakes along the 1500 km long NAF repeatedly occurred and interacted each other. The recent large northern Aegean earthquake with Mw=6.9 filled one of the last two seismic gaps on NAF that experienced extraordinary seismic moment release cycle during the last century and confirmed a remained blank zone in the Marmara Sea. However, this segment keeps its mystery due to its underwater location. Earthquake hazard and disaster mitigation studies in Marmara region are sensitive to detailed information on fault geometry and its stick-slip behavior beneath the western Marmara Sea. We have started ocean bottom seismographic observations to obtain the detailed information about fault geometry and its stick-slip behavior beneath the western Marmara Sea, as a part of the SATREPS collaborative project between Japan and Turkey namely "Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education in Turkey". The target area spans from western Marmara Sea to offshore Istanbul along the NAF. In the beginning of the project, we deployed ten Ocean Bottom Seismographs (OBSs) between the Tekirdag Basin and the Central Basin (CB) in September 2014. Then, we added five Japanese OBSs and deployed them in the western end of the Marmara Sea and in the eastern CB to extend the observed area in March 2015. We retrieved all 15 OBSs in July 2015 and deployed them again in the same locations after data retrieve and battery maintenance. From continuous OBS records, we could detect more than 700 events near the seafloor trace of NAF during 10 months observation period whereas land-seismic network could detect less than 200 events. We estimated the micro-earthquake location using manual-picking arrival times incorporating station corrections. The tentative results show heterogeneous seismicity. The Western High (WH) and CB have relative high seismicity and the seismogenic zone was found to be thicker than the previous estimations done by other researchers. Our result clearly shows that the maximum depth of seismogenic zone is about 24 km beneath the WH and the western half of CB. This depth suddenly decrease to about 15 km in the eastern half of CB, suggesting that there is some structural or frictional boundary on NAF around 28°E. Our results also suggested that the dip angle of NAF is almost vertical beneath WH, whereas it is about 10 degrees southward dipping beneath the eastern CB. We will perform local seismic tomography to obtain more precious hypocenter location and fault geometry.

  18. Features of autumnal differential coastal cooling in south-eastern Baltic deduced from data of MODIS spectroradiometers

    NASA Astrophysics Data System (ADS)

    Esiukova, Elena; Chubarenko, Irina

    2013-04-01

    Characteristics of profiles of sea surface temperature (SST) from the coastline to deep sea area in Russian sector of the South-Eastern Baltic Sea during seasonal autumnal cooling are identified using the data of spectroradiometers MODIS Aqua. Time periods are chosen when vertical convection and wind mixing make the upper layer (~ 30-40 m) in deep-sea area practically isothermal, and significant horizontal gradients of temperature/density are formed above shallows and underwater coastal slopes. This picture of differential cooling is formed by the combined action of heat exchange with the atmosphere (which is practically the same in coastal and open areas) and horizontal transport of heat from the sea to the shallow/coastal zone. This allows for estimation of horizontal heat and mass transport between the deep and the coastal area. The images of October-November 2002-2009 were analyzed, corresponding to periods of fast decrease of air temperature (at a rate of 0.86-2.54 °C/day). Significant linear portion in shallow-most paret is found to be a characteristic feature of the profiles, which is detected above all types of slopes (steep, sloping, irregular), reaching 20% to 70% of the length of the slope. Comparative analysis of the characteristics of the observed profiles above different slopes at the same image, and for the same slope at different dates was performed. The actual profiles of SST are compared with several theoretically predicted cases (in the absence of horizontal exchange, in of the quasi-stationary exchange), and the modeling results. Estimations suggest that horizontal gradient of water temperature favours seasonal slide of the cold/dense water along the underwater slopes (cascading) with a fairly high speed, reaching tens of cm/s at the shelf edge in the case of rapid cooling of water above the underwater slopes. Current speed at the end of the slopes may be quite high (8-20 cm/s), but comparable to the known values. On the base of numerical modeling results, the maximum speed of 5-7 cm/s obtained. The resulting specific volumetric flow rate, estimated from remote sensing data (1.2-4.8 m**2/s) is comparable to that obtained by numerical modeling (2.6-6.0 m**2/s). The specific volumetric flow-rates at the end of the slopes/shelf break is also similar to that observed in other basins (e.g., in Lake Geneva - 0.4-1 m**2/s, Lake Baikal - 5 m**2/s). The analysis was conducted with the support of RFBR, grants number 10-05-00540a, 10-05-00472a, 11-05-00674a. Intellectual property rights to the original data of MODIS Aqua belong to American space agency (NASA).

  19. Variability in Aerosol Optical and Physical Properties at a Coastal Industrial City in India, deduced from OMI and MODIS data

    NASA Astrophysics Data System (ADS)

    Das, B.; Ahn, C.; Torres, O.

    2009-12-01

    Many cities in India have gone through industrial revolution due to the priorities put by the State and Central Governments for economical growth. Bhubaneswar is one of the cities in the eastern part of India (85.8 E and 20.2 N) that has been the center of industrial activities since 1990s. A number of industries such as thermal power plants, sponge iron plants and housing developments have resulted changes in the land cover and in the slow deterioration of air quality affecting public health and reduced visibility. The primary purpose of this study is to understand the variability in aerosol optical and physical properties in Bhubaneswar using remote sensing data produced by OMI (Ozone Monitoring Instrument) and MODIS (Moderate Resolution Imaging Spectroradiometer). We have analyzed the data for Aerosol Extiction Optical Depth (AOD), Aerosol Absorption Optical Depth (AAOD), UV Aerosol Index and Cloud Fraction from OMI and Aerosol Small Mode Fraction, Aerosol Optical Depth (AOD), Cloud Optical Depth (COD), Aerosol Mass over Land from MODIS. The analysis has been made for 4 years from 2005-2008. Variations in AOD and AAOD values are observed during pre-monsoon, monsoon and post-monsoon periods.

  20. Deep crustal structure off Akita, eastern margin of the Japan Sea, deduced from ocean bottom seismographic measurements

    NASA Astrophysics Data System (ADS)

    Nishizawa, Azusa; Asada, Akira

    1999-06-01

    A seismic exploration was carried out to detect the heterogeneity of the seismic wavespeed structure associated with the plate convergence at the eastern margin of the Japan Sea. Two airgun-OBS (ocean bottom seismograph) profiles were shot off Akita, Japan, where a seismic gap seems to exist but the location of the plate boundary has not been confirmed. One of the profiles was 60 km long, trending NNE-SSW, named Line OBS-9, at the northeastern end of the Yamato Basin and the other was 170 km long, trending WNW-ESE, Line NT95-1, parallel to the direction of the supposed plate convergence. The crustal structure beneath Line OBS-9 consists of six layers. The uppermost layer is sediment. Three layers are identified beneath the top sedimentary layer and their P wavespeeds are estimated to be 3.3-3.4 km/s, 5.1-5.4 km/s and 5.8-6.3 km/s, which corresponds to the upper crust. Underneath these layers, a layer with P wavespeed ranges of 6.3-7.2 km/s comprises the middle and lower crust. The depth of Moho is inferred to be 19 km. These wavespeed values are comparable with those of the present Japanese island arc, while the thickness of the crust is one-half of that of the Japanese arc. The crustal model supports the scenario that the Yamato Basin is formed by extension of the island arc. The crustal model for Line NT95-1 shows a transition from the extended island arc structure beneath the Yamato Basin to a thicker crust similar to the Japanese arc. P wavespeed heterogeneity related to the plate boundary is not detected. However, a significant change in the structural model along the profile is found around the region where the largest change in the seafloor topography exists. In that region, the wavespeeds in the middle crust have lower values than those of the neighboring area and the Moho begins to deepen towards the Japanese island arc. From comparison with the relationship between P wavespeed structure and aftershock distribution of the 1993 Hokkaido-Nansei-Oki earthquake (southwest of Hokkaido, MJMA 7.8), the region may correspond to a possible fault position of the pending earthquake.

  1. Ionospheric Response to the Total Solar Eclipse of 22 July 2009 as Deduced from VLBI and GPS Data

    NASA Technical Reports Server (NTRS)

    Guo, L.; Shu, F. C.; Zheng, W. M.; Kondo, T.; Ichikawa, R.; Hasegawa, S.; Sekido, M.

    2010-01-01

    A total solar eclipse occurred over China at latitudes of about 30 N on the morning of 22 July 2009, providing a unique opportunity to investigate the influence of the sun on the earth's upper ionosphere. GPS observations from Shanghai GPS Local Network and VLBI observations from stations Shanghai, Urumqi, and Kashima were used to observe the response of TEC to the total solar eclipse. From the GPS data reduction, the sudden decrease of TEC at the time of the eclipse, amounting to 2.8 TECU, and gradual increase of TEC after the eclipse were found by analyzing the diurnal variations. More distinctly, the variations of TEC were studied along individual satellite passes. The delay in reaching the minimum level of TEC with the maximum phase of eclipse was 5-10 min. Besides, we also compared the ionospheric activity derived from different VLBI stations with the GPS results and found a strong correlation between them.

  2. Introducing Fourier-domain mobility spectrum analysis (FMSA) to deduce multi-component carrier mobility and density

    NASA Astrophysics Data System (ADS)

    Cui, Boya; Tang, Yang; Grayson, M.

    2015-01-01

    Compounds and heterostructures in optical devices often host multiple carrier species that contribute simultaneously to the total electrical conduction, making it difficult to distinguish the characteristics of each type. Here a Fourier-domain Mobility Spectrum Analysis (FMSA)1 is introduced to sort the conductivity contributions of different carrier species from magnetotransport measurements. Using simulated magnetotransport data from 0 to 15 T of a simple initial trial spectrum, FMSA iteratively adjusts the spectral points in either the mobility domain or its Fourier reciprocal space to fit a mobility range spanning over three orders of magnitude (μ = 670 ~ 1,000,000 cm2/V·s). With its alternating local and global adjustments, FMSA is able to recover the mobility distribution of test data, as verified in convergence plots of the total error as a function of iteration number. This technique resolves the mobility spectra as well or better than competing MSA techniques with a simple and elegant algorithm, while precisely resolving the smoothness and width of mobility peaks without artificial broadening.

  3. On the Distribution of Ion Density Depletion Along Magnetic Field Lines as Deduced Using C-NOFS

    NASA Technical Reports Server (NTRS)

    Dao, E.; Kelley, M. C.; Hysell, D. L.; Retterer, J. M.; Su, Y.-J.; Pfaff, Robert F.; Roddy, P. A.; Ballenthin, J. O.

    2012-01-01

    To investigate ion density depletion along magnetic field lines, we compare in situ-measured ion density fluctuations as seen from C/NOFS and compare them to the field-line-integrated depletion of the whole bubble as inferred from electric field measurements. Results show that, within C/NOFS' range, local measurement of the normalized density depletion, (Delta)n/n(sub 0), near the apex may be far less than at other points on the same field line. We argue that the distribution of (Delta)n/n(sub 0) is a weighted distribution concentrated at latitudes of the Appleton anomalies and becomes more heavily weighted the closer the field-aligned bubble rises to the peak of the anomalies. A three-dimensional simulation of an ionospheric bubble verifies our arguments.

  4. Tectonics of the baikal rift deduced from volcanism and sedimentation: a review oriented to the Baikal and Hovsgol lake systems.

    PubMed

    Ivanov, Alexei V; Demonterova, Elena I

    2009-01-01

    As known from inland sedimentary records, boreholes, and geophysical data, the initiation of the Baikal rift basins began as early as the Eocene. Dating of volcanic rocks on the rift shoulders indicates that volcanism started later, in the Early Miocene or probably in the Late Oligocene. Prominent tectonic uplift took place at about 20 Ma, but information (from both sediments and volcanics) on the initial stage of the rifting is scarce and incomplete. A comprehensive record of sedimentation derived from two stacked boreholes drilled at the submerged Akademichesky ridge indicates that the deep freshwater Lake Baikal existed for at least 8.4 Ma, while the exact formation of the lake in its roughly present-day shape and volume is unknown. Four important events of tectonic/environmental changes at about approximately 7, approximately 5, approximately 2.5, and approximately 0.1 Ma are seen in that record. The first event probably corresponds to a stage of rift propagation from the historical center towards the wings of the rift system. Rifting in the Hovsgol area was initiated at about this time. The event of ~5 Ma is a likely candidate for the boundary between slow and fast stages of rifting. It is reflected in a drastic change of sedimentation rate due to isolation of the Akademichesky ridge from the central and northern Lake Baikal basins. The youngest event of 0.1 Ma is reflected by the (87)0Sr/ (86)Sr ratio increase in Lake Baikal waters and probably related to an increasing rate of mountain growth (and hence erosion) resulting from glacial rebounding. The latter is responsible for the reorganization of the outflow pattern with the termination of the paleo-Manzurka outlet and the formation of the Angara outlet. The event of approximately 2.5 Ma is reflected in the decrease of the (87)Sr/(86)Sr and Na/Al ratios in Lake Baikal waters. We suggest that it is associated with a decrease of the dust load due to a reorganization of the atmospheric circulations in Mainland Asia. All these tectonic and climatic events could (and actually did) influence the biota of Lake Baikal. The Hovsgol rift basin was shaped to its recent form between 5.5 and 0.4 Ma. However, freshwater Lake Hovsgol appeared only in the latest pre-Holocene time as a result of meltwater inflow and increase of atmospheric precipitations during the Bølling-Allerød warming. Prior to this, a significantly smaller, saline outflow-free precursor of Lake Hovsgol existed. It explains why two, now connected, lakes of similar water chemistry within similar climatic and tectonic conditions differ so much in their biodiversity. PMID:19198772

  5. Age of Giordano Bruno crater as deduced from the morphology of its secondaries at the Luna 24 landing site

    NASA Astrophysics Data System (ADS)

    Basilevsky, A. T.; Head, J. W.

    2012-12-01

    We undertook a photogeologic study of Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) images of the ejecta of the very young 22-km diameter crater Giordano Bruno (GB) and for the Luna 24 landing site region, where secondary craters from Giordano Bruno are observed. Using the technique of Basilevsky (1976) for estimating the absolute ages of small lunar craters based on their morphologic prominence and size, craters near the Luna 24 site considered to be secondaries of Giordano Bruno crater and craters superposed on ejecta of Giordano Bruno crater are found to have approximately the same age: somewhere between 5 and 10 m.y. This suggests that the craters at the Luna 24 site are indeed secondaries of GB crater and that this age range is an estimate for the time of GB crater formation. Our results generally agree with estimates derived from counts of small craters superposed on GB ejecta: 1-10 m.y. and with the exposure age of one of the samples derived from Zone I of the Luna 24 core. Plescia et al. (2010b) interpreted a large fraction of the craters superposed on GB ejecta and floor not as primary craters, but rather as secondary craters formed from the GB event itself. On this basis, it was postulated that GB may be formed by an historic impact. Our new data and analysis do not support an age as young as historical. The general agreement of our results for age determination for the GB secondaries of the Luna 24 area, and for craters superposed on the GB ejecta, with the age estimate based on crater count and with the mentioned exposition age of one of the Luna 24 samples, also validates the technique of Basilevsky (1976). A special study of the Luna 24 samples should be undertaken designed to find records of the formation age of the crater on whose rim Luna 24 landed, thus better constraining the age of GB crater.

  6. Following the Viterbi Path to Deduce Flagellar Actin-Interacting Proteins of Leishmania spp.: Report on Cofilins and Twinfilins

    NASA Astrophysics Data System (ADS)

    Pacheco, Ana Carolina L.; Araújo, Fabiana F.; Kamimura, Michel T.; Medeiros, Sarah R.; Viana, Daniel A.; Oliveira, Fátima de Cássia E.; Filho, Raimundo Araújo; Costa, Marcília P.; Oliveira, Diana M.

    2007-11-01

    For performing vital cellular processes, such as motility, eukaryotic cells rely on the actin cytoskeleton, whose structure and dynamics are tightly controlled by a large number of actin-interacting (AIP) or actin-related/regulating (ARP) proteins. Trypanosomatid protozoa, such as Leishmania, rely on their flagellum for motility and sensory reception, which are believed to allow parasite migration, adhesion, invasion and even persistence on mammalian host tissues to cause disease. Actin can determine cell stiffness and transmit force during mechanotransduction, cytokinesis, cell motility and other cellular shape changes, while the identification and analyses of AIPs can help to improve understanding of their mechanical properties on physiological architectures, such as the present case regarding Leishmania flagellar apparatus. This work conveniently apply bioinformatics tools in some refined pattern recognition techniques (such as hidden Markov models (HMMs) through the Viterbi algorithm/path) in order to improve the recognition of actin-binding/interacting activity through identification of AIPs in genomes, transcriptomes and proteomes of Leishmania species. We here report cofilin and twinfilin as putative components of the flagellar apparatus, a direct bioinformatics contribution in the secondary annotation of Leishmania and trypanosomatid genomes.

  7. Proof of concept study with an HER-2 mimotope anticancer vaccine deduced from a novel AAV-mimotope library platform

    PubMed Central

    Singer, Josef; Manzano-Szalai, Krisztina; Fazekas, Judit; Thell, Kathrin; Bentley-Lukschal, Anna; Stremnitzer, Caroline; Roth-Walter, Franziska; Weghofer, Margit; Ritter, Mirko; Pino Tossi, Kerstin; Hörer, Markus; Michaelis, Uwe; Jensen-Jarolim, Erika

    2016-01-01

    ABSTRACT Background: Anticancer vaccines could represent a valuable complementary strategy to established therapies, especially in settings of early stage and minimal residual disease. HER-2 is an important target for immunotherapy and addressed by the monoclonal antibody trastuzumab. We have previously generated HER-2 mimotope peptides from phage display libraries. The synthesized peptides were coupled to carriers and applied for epitope-specific induction of trastuzumab-like IgG. For simplification and to avoid methodological limitations of synthesis and coupling chemistry, we herewith present a novel and optimized approach by using adeno-associated viruses (AAV) as effective and high-density mimotope-display system, which can be directly used for vaccination. Methods: An AAV capsid display library was constructed by genetically incorporating random peptides in a plasmid encoding the wild-type AAV2 capsid protein. AAV clones, expressing peptides specifically reactive to trastuzumab, were employed to immunize BALB/c mice. Antibody titers against human HER-2 were determined, and the isotype composition and functional properties of these were tested. Finally, prophylactically immunized mice were challenged with human HER-2 transfected mouse D2F2/E2 cells. Results: HER-2 mimotope AAV-vaccines induced antibodies specific to human HER-2. Two clones were selected for immunization of mice, which were subsequently grafted D2F2/E2 cells. Both mimotope AAV clones delayed the growth of tumors significantly, as compared to controls. Conclusion: In this study, a novel mimotope AAV-based platform was created allowing the isolation of mimotopes, which can be directly used as anticancer vaccines. The example of trastuzumab AAV-mimotopes demonstrates that this vaccine strategy could help to establish active immunotherapy for breast-cancer patients. PMID:27622022

  8. OBSERVATIONS OF THE INTERPLANETARY HYDROGEN DURING SOLAR CYCLES 23 AND 24. WHAT CAN WE DEDUCE ABOUT THE LOCAL INTERSTELLAR MEDIUM?

    SciTech Connect

    Vincent, Frédéric E.; Quémerais, Eric; Koutroumpa, Dimitra; Ben-Jaffel, Lotfi; Harris, Walter M.; Clarke, John

    2014-06-20

    Observations of interstellar helium atoms by the Interstellar Boundary Explorer (IBEX) spacecraft in 2009 reported a local interstellar medium (LISM) velocity vector different from the results of the Ulysses spacecraft between 1991 and 2002. The interplanetary hydrogen (IPH), a population of neutrals that fills the space between planets inside the heliosphere, carries the signatures of the LISM and its interaction with the solar wind. More than 40 yr of space-based studies of the backscattered solar Lyα emission from the IPH provided limited access to the velocity distribution, with the first temporal evolution map of the IPH line-shift during solar cycle 23. This work presents the results of the latest IPH observations made by the Hubble Space Telescope's Space Telescope Imaging Spectrograph during solar cycle 24. These results have been compiled with previous measurements, including data from the Solar Wind Anisotropies instrument on the Solar and Heliospheric Observatory. The whole set has been compared to physically realistic models to test both sets of LISM physical parameters as measured by Ulysses and IBEX, respectively. This comparison shows that the LISM velocity vector has not changed significantly since Ulysses measurements.

  9. Structural features that specify tyrosine kinase activity deduced from homology modeling of the epidermal growth factor receptor.

    PubMed Central

    Knighton, D R; Cadena, D L; Zheng, J; Ten Eyck, L F; Taylor, S S; Sowadski, J M; Gill, G N

    1993-01-01

    To identify structural features that distinguish protein-tyrosine kinases from protein-serine kinases, a molecular model of the kinase domain of epidermal growth factor receptor was constructed by substituting its amino acid sequence for the amino acid sequence of the catalytic subunit of cAMP-dependent protein kinase in a 2.7-A refined crystallographic model. General folding was conserved as was the configuration of invariant residues at the active site. Two sequence motifs that distinguish the two families correspond to loops that converge at the active site of the enzyme. A conserved arginine in the catalytic loop is proposed to interact with the gamma phosphate of ATP. The second loop provides a binding surface that positions the tyrosine of the substrate. A positively charged surface provides additional sites for substrate recognition. Images Fig. 2 Fig. 3 Fig. 4 PMID:8389462

  10. Global characteristics of the cold plasma in the equatorial plasmapause region as deduced from the geos 1 mutual impedance probe

    SciTech Connect

    Decreu, P.M.E.; Beghin, C.; Parrot, M.

    1982-02-01

    Thermal plasma parameters derived by the muntal impedance experiment on GEOS are described. The experiment is well suited to the measurement of the electron density and temperature of the outer plasmasphere (when kT/sub e//N/sub e/<1.6 eV/cm/sup 3/). This investigation of the whole set of data supplied by GEOS 1 (4

  11. COMPLEX FRAMESHIFT MUTATIONS MEDIATED BY PLASMID PKM101: MUTATIONAL MECHANISMS DEDUCED FROM 4-AMINOBIPHENYL-INDUCED MUTATION SPECTRA IN SALMONELLA

    EPA Science Inventory

    We used colony probe hybridization and PCR/DNA sequencing to determine the mutations -aminobiphenyl (4-AB) +S9-induced revertants of the -1 frameshift allele in 2,300 4-aminobiphenyl of the base-substitution allele hisD3052 in strains TA1978, TA1538, and TA98 and were at strains ...

  12. Ionospheric variations in the period range of days to tens of days deduced from HF Doppler observation

    NASA Astrophysics Data System (ADS)

    Shibata, Takashi; Yoshimura, Yasuo; Okuzawa, Takashi; Ogawa, Toshio

    Ionospheric variations in the period range of a few days to tens of days observed by the HF Doppler (HFD) method for the entire year of 1986 have been investigated by a spectrum analysis. The crystal oscillator employed has a stability of up 5 x 10 to the -9th/day at the primary stage of 5 MHz. The present method was shown to be capable of detecting ionospheric variations in the period range of both 3 to about 13 days and 16 to about 21 days. It is suggested that a 27-day period was not observed in both the HFD and the foF2 spectra due to minimum solar activity.

  13. Vegetation history of central Chukotka deduced from permafrost paleoenvironmental records of the El'gygytgyn Impact Crater

    NASA Astrophysics Data System (ADS)

    Andreev, A. A.; Morozova, E.; Fedorov, G.; Schirrmeister, L.; Bobrov, A. A.; Kienast, F.; Schwamborn, G.

    2012-08-01

    Frozen sediments from three cores bored in the permafrost surrounding the El'gygytgyn Impact Crater Lake have been studied for pollen, non-pollen palynomorphs, plant macrofossils and rhizopods. The palynological study of these cores contributes to a higher resolution of time intervals presented in a poor temporal resolution in the lacustrine sediments; namely the Allerød and succeeding periods. Moreover, the permafrost records better reflect local environmental changes, allowing a more reliable reconstruction of the local paleoenvironments. The new data confirm that shrub tundra with dwarf birch, shrub alder and willow dominated the lake surroundings during the Allerød warming. Younger Dryas pollen assemblages reflect abrupt changes to grass-sedge-herb dominated environments reflecting significantly drier and cooler climate. Low shrub tundra with dwarf birch and willow dominate the lake vicinity at the onset of the Holocene. The find of larch seeds indicate its local presence around 11 000 cal yr BP and, thus a northward shift of treeline by about 100 km during the early Holocene thermal optimum. Forest tundra with larch and shrub alder stands grew in the area during the early Holocene. After ca. 3500 cal yr BP similar-to-modern plant communities became common in the lake vicinity.

  14. Vegetation history of Central Chukotka deduced from permafrost paleoenvironmental records of the El'gygytgyn Impact Crater

    NASA Astrophysics Data System (ADS)

    Andreev, A. A.; Morozova, E.; Fedorov, G.; Schirrmeister, L.; Bobrov, A. A.; Kienast, F.; Schwamborn, G.

    2012-04-01

    Frozen sediments from three cores bored in permafrost surrounding of the El'gygytgyn Impact Crater Lake have been studied for pollen, non-pollen palynomorphs, plant macrofossils, and rhizopods. The palynological study of the cores contributes to a higher resolution of time intervals presented in a poor temporal resolution in the lacustrine sediments; namely the Allerød and succeeding periods. Moreover, permafrost records better reflect local environmental changes, thus, allowing more reliable reconstruction of the local paleoenvironments. The new data confirm that shrub tundra with dwarf birch, shrub alder and willow dominated in the lake surroundings during the Allerød warming. Younger Dryas pollen assemblages reflect abrupt changes to grass-sedge-herb dominated environments reflecting significant climate deterioration. Low shrub tundra with dwarf birch and willow dominate the lake vicinity at the onset of the Holocene. The founds of larch seeds indicate its local presence around 11 000 cal. yr BP and, thus a northward shift of treeline by about 100 km during the early Holocene thermal optimum. Forest tundra with larch and shrub alder stands grew in the area during the early Holocene. After ca. 3500 cal. yr BP similar-to-modern plant communities became common in the lake vicinity.

  15. Correlation between magnetic and electric field perturbations in the field-aligned current regions deduced from DE 2 observations

    NASA Technical Reports Server (NTRS)

    Ishii, M.; Sugiura, M.; Iyemori, T.; Slavin, J. A.

    1992-01-01

    The satellite-observed high correlations between magnetic and electric field perturbations in the high-latitude field-aligned current regions are investigated by examining the dependence of the relationship between Delta-B and E on spatial scale, using the electric and magnetic field data obtained by DE 2 in the polar regions. The results are compared with the Pedersen conductivity inferred from the international reference ionosphere model and the Alfven wave velocity calculated from the in situ ion density and magnetic field measurements.

  16. Membrane fluidity profiles as deduced by saturation-recovery EPR measurements of spin-lattice relaxation times of spin labels

    PubMed Central

    Mainali, Laxman; Feix, Jimmy B.; Hyde, James S.; Subczynski, Witold K.

    2011-01-01

    There are no easily obtainable EPR spectral parameters for lipid spin labels that describe profiles of membrane fluidity. The order parameter, which is most often used as a measure of membrane fluidity, describes the amplitude of wobbling motion of alkyl chains relative to the membrane normal and does not contain explicitly time or velocity. Thus, this parameter can be considered as nondynamic. The spin-lattice relaxation rate (T−11) obtained from saturation-recovery EPR measurements of lipid spin labels in deoxygenated samples depends primarily on the rotational correlation time of the nitroxide moiety within the lipid bilayer. Thus, T−11 can be used as a convenient quantitative measure of membrane fluidity that reflects local membrane dynamics. T−11 profiles obtained for 1-palmitoyl-2-(n-doxylstearoyl)phosphatidylcholine (n-PC) spin labels in dimyristoylphosphatidylcholine (DMPC) membranes with and without 50 mol% cholesterol are presented in parallel with profiles of the rotational diffusion coefficient, R⊥, obtained from simulation of EPR spectra using Freed's model. These profiles are compared with profiles of the order parameter obtained directly from EPR spectra and with profiles of the order parameter obtained from simulation of EPR spectra. It is shown that T−11 and R⊥ profiles reveal changes in membrane fluidity that depend on the motional properties of the lipid alkyl chain. We find that cholesterol has a rigidifying effect only to the depth occupied by the rigid steroid ring structure and a fluidizing effect at deeper locations. These effects cannot be differentiated by profiles of the order parameter. All profiles in this study were obtained at X-band (9.5 GHz). PMID:21868272

  17. Simulation of EAS properties on the basis of high energy interaction model deduced from the accelerator data

    NASA Technical Reports Server (NTRS)

    Kubiak, G.; Szabelski, J.; Wdeyozyk, J.; Wolfendale, A. W.

    1985-01-01

    Calculations of extensive air showers in atmosphere were performed using formulae describing p-p and p-air nucleus interactions. The formulae fitted to the accelerator data were extrapolated taking the same trend up to 10 to the 16 eV. Above that energy it was assumed that the degree of scaling violating/alpha-parameter/ is saturating or even decreasing. The latter assumption follows from earlier work where it was found that without this restriction shower maxima at the highest energies are located too high in the atmosphere. Results of calculations have been compared with experimental data. The comparison was made separately for the curves obtained from the so called equal intensity cuts and for the Cerenkov data.

  18. Relationship between surface and subsurface structures of the northern Atlas foreland of Tunisia deduced from regional gravity analysis

    NASA Astrophysics Data System (ADS)

    Frifita, N.; Arfaoui, M. S.; Zargouni, F.

    2016-08-01

    Gravity data were analyzed in the northern Atlas of Tunisia in order to identify the deep structures of the region and their relationship to the geological outcrop. The analysis based on the Bouguer gravity maps related to upward continuation at 1, 2, 4, 6, 10 and 12 km. The lineaments obtained by the horizontal gradient method were interpreted as deep faults with two global directions NE–SW and NW–SE related to major tectonic corridors. These lineaments were confirmed by the automatic estimation of depth solutions using the Euler deconvolution technique. By separation between the gravity anomaly bodies in different levels, it shows that almost all of the lineaments are oriented in NE–SW and NW–SE directions. The NW–SE-trending lineaments are related to deep faults and the NE–SW-oriented lineaments define the global direction of the surface, and they are related to shallow structures. 2.5D gravity modeling was used to improve the results obtained by the Maxima and the Euler deconvolution techniques. The 2.5D model points out the variation of depths of the NE–SW-trending major faults. In this study, we demonstrate the relationship between the NE–SW and the NW–SE directions. These two major sets of faults have been determined by the statistical study of the lineaments. This study confirms some faults already recognized or supposed by the classical geological studies, and it also detects a new deep fault masked in the surface, and gives information about major fault depths and the relation between different structures.

  19. Towards the kinetics of diagenetic overprint processes deduced from laboratory-based hydrothermal alteration of modern Arctica islandica shell material

    NASA Astrophysics Data System (ADS)

    Casella, Laura A.; Griesshaber, Erika; Mavromatis, Vasileios; Dietzel, Martin; Immenhauser, Adrian; Schmahl, Wolfgang W.

    2016-04-01

    Benthic and nektonic marine biogenic carbonate archives represent the foundation of numerous studies aiming at paleo-environment reconstructions. However, living organisms are not in thermodynamic equilibrium as they form local chemical environments for physiologic processes such as biological mineralization of their hard tissues. This disequilibrium is not sustained after death and all biological tissues are altered by equilibration with the surrounding environment: diagenesis. To understand transformation during diagenesis we performed laboratory-based hydrothermal alteration experiments on Arctica islandica shells at four different temperatures between 100 °C and 175 °C treated in simulated meteoric and burial waters, respectively. We investigated, relative to unaltered shells, the kinetics of Arctica islandica bioaragonite to calcite transition as well as microstructural- and nanostructural characteristics of the altered shells with X-ray diffraction, micro-Raman, high-resolution SEM and EBSD. At hydrothermal treatment at 100 °C bioaragonite - although metastable at 1 bar - does not transform to calcite, even in meteoric fluids and over a time period of 28 days. We noted a drastic recrystallization from the initial fine-grained fractal microstructure and pronounced axial texture to a new and still fine-grained microstructure with an almost randomized orientation distribution. At 175 °C the transformation to coarse-grained calcite is complete after 8 days. Calcite formation starts after a passive incubation period of 4 days; after 6 days the aragonite is almost completely transformed. In solutions simulating meteoric water the grain size of the newly formed calcite reaches 100-150 μm, while in burial fluids the calcite reaches sizes in the 1mm range during 28 days of alteration. Phase transformation proceeds where the hydrothermal fluid is in contact with the aragonite: at shell surfaces, around pores and in growth lines. Our observations lead us to the following conclusions: Surprisingly, we do not only observe transformation of nominally metastable bioaragonite to calcite, we also observe recrystallization of bioaragonite to aragonite and biocalcite to calcite. All these types of recrystallization significantly reduce the crystallographic preferred orientation, which is characteristic for the original biological hard tissue. The newly formed crystals do not nucleate epitaxially on the original material, and this causes the randomized crystallographic orientation after diagenetic overprinting. The driving force for recrystallization is due to internal stresses caused by organic matrices and interface energies related to the nanoscale fabric of the biomineral. The pores left behind by decomposed organic matrix apparently serve as nucleation sites for newly formed mineral.

  20. Late Holocene climates of the Near East deduced from Dead Sea level variations and modern regional winter rainfall

    NASA Astrophysics Data System (ADS)

    Enzel, Yehouda; Bookman (Ken Tor), Revital; Sharon, David; Gvirtzman, Haim; Dayan, Uri; Ziv, Baruch; Stein, Mordechai

    2003-11-01

    The Dead Sea is a terminal lake of one of the largest hydrological systems in the Levant and may thus be viewed as a large rain gauge for the region. Variations of its level are indicative of the climate variations in the region. Here, we present the decadal- to centennial-resolution Holocene lake-level curve of the Dead Sea. Then we determine the regional hydroclimatology that affected level variations. To achieve this goal we compare modern natural lake-level variations and instrumental rainfall records and quantify the hydrology relative to lake-level rise, fall, or stability. To quantify that relationship under natural conditions, rainfall data pre-dating the artificial Dead Sea level drop since the 1960s are used. In this respect, Jerusalem station offers the longest uninterrupted pre-1960s rainfall record and Jerusalem rains serve as an adequate proxy for the Dead Sea headwaters rainfall. Principal component analysis indicates that temporal variations of annual precipitation in all stations in Israel north of the current 200 mm yr -1 average isohyet during 1940-1990 are largely synchronous and in phase (˜70% of the total variance explained by PC1). This station also represents well northern Jordan and the area all the way to Beirut, Lebanon, especially during extreme drought and wet spells. We (a) determine the modern, and propose the past regional hydrology and Eastern Mediterranean (EM) climatology that affected the severity and length of droughts/wet spells associated with multiyear episodes of Dead Sea level falls/rises and (b) determine that EM cyclone tracks were different in average number and latitude in wet and dry years in Jerusalem. The mean composite sea level pressure and 500-mb height anomalies indicate that the potential causes for wet and dry episodes span the entire EM and are rooted in the larger-scale northern hemisphere atmospheric circulation. We also identified remarkably close association (within radiocarbon resolution) between climatic changes in the Levant, reflected by level changes, and culture shifts in this region.

  1. High latitude field aligned light ion flows in the topside ionosphere deduced from ion composition and plasma temperatures

    NASA Technical Reports Server (NTRS)

    Grebowsky, J. M.; Hoegy, W. R.; Chen, T. C.

    1993-01-01

    Using a comprehensive ionospheric data set comprised of all available ion composition and plasma temperature measurements from satellites, the vertical distributions of ion composition and plasma temperatures are defined from middle latitudes up into the polar cap for summer conditions for altitudes below about 1200 km. These data are sufficient to allow a numerical estimation of the latitudinal variation of the light ion outflows from within the plasmasphere to the polar wind regions. The altitude at which significant light ion outflow begins is found to be lower during solar minimum conditions than during solar maximum. The H(+) outward speeds are of the order of 1 km/s near 1100 km during solar maximum but attain several km/s speeds for solar minimum. He(+) shows a similar altitude development of flow but attains polar cap speeds much less than 1 km/s at altitudes below 1100 km, particularly under solar maximum conditions. Outward flows are also found in the topside F-region for noontime magnetic flux tubes within the plasmasphere.

  2. Structural evolution of lamprophyric dikes in Lailai, northeastern coast of Taiwan, deduced from mesoscopic structures in dikes and country rocks

    NASA Astrophysics Data System (ADS)

    You, Cian-Siang; Huang, Wen-Jeng; Lo, Wei; Wang, Tzu-Bin; Chen, Chien-Chih

    2015-04-01

    Lamprophyric dikes are standing in right-stepping en echelon up to 2.3 meters high within the Oligocene Tatungshan formation on the Lai-Lai wave-cut platform in the northeastern coast of Taiwan. The marine platform composed mainly of argillite is the extension of Hsuehshan range, which has the tallest peak of 3,886 m high in Taiwan. The dikes formed at depth in the late Miocene of 9±1.1 Ma ago are exposed on the marine platform nowadays due to the exhumation and Penglai orogeny resulting from the collision of Eurasian plate and Philippine Sea plate, which began in Pleistocene of 5-6 Ma ago. In consequence, folds, faults, joints and other structures are associated with them. In this study, the distribution of the dikes and fractures were mapped by conducting accurate surveys with a total station theodolite and orthorectifying aerial images taken by an unmanned aerial vehicle in different elevations. Electrical resistivity exploration was performed to decipher the arrangement of the dikes underground and the characteristics of the faults. The associated mesoscopic structures were delineated by mapping at a scale of 1: 40 in the field. We infer that the dikes was formed at depth of approximately 2.4 kilometers according to the thickness of overlaying sedimentary rocks formed from late Oligocene to late Miocene. Thus, it excludes the possibility that fractures existed before the lamprophyric magma intruded into the country rocks. Our observations help restore the original status of the current 19 dike segments. We conclude that the lamprophyric magma forcedly and vertically intruded into the Oligocene rocks and the direction change of maximum principle stress at depth of 2.4 kilometers resulted in three or more right-stepping en-echelon dikes.

  3. Application of geochemical techniques to deduce the reservoir performance of the Palinpinon Geothermal Field, Philippines - an update

    SciTech Connect

    Ramos-Candelaria, M.N.; Garcia, S.E.; Hermoso, D.Z.

    1997-12-31

    Regular monitoring of various geochemical parameters in the water and vapor phases of the production wells at the Palinpinon I and II sectors of the Southern Negros Geothermal Field have been useful in the identification of the dominant reservoir processes occurring related to the present exploitation strategy. Observed geochemical and physical changes in the output of production wells have dictated production and injection strategies adopted to maximize production to meet the steam requirements of the power plant. Correlation of both physical and chemical data have identified the following reservoir processes: (1) Injection breakthrough via the Ticala Fault of the highly mineralized (Cl {approximately}8,000-10,500 mg/kg), isotopically enriched ({delta}{sup 18}O = -3.00{per_thousand}, {delta}{sup 2} H = -39{per_thousand}), and gas depleted brine for wells in the SW and central Puhagan. Injection breakthrough is also occurring in Palinpinon II and has resulted in temperature drops of 5-10{degrees}C.2. Pressure drawdown enhanced boiling in the liquid reservoir with steam separation of 220-240{degrees}C, feeding wells tapping the natural steam zone. However, enhanced drawdown has induced the entry of shallow acid steam condensate fluids in some wells (e.g. OK-7, PN-29D, PN-18D), which if not arrested could reduce production.

  4. Level and length of cyclic solar activity during the Maunder minimum as deduced from the active-day statistics

    NASA Astrophysics Data System (ADS)

    Vaquero, J. M.; Kovaltsov, G. A.; Usoskin, I. G.; Carrasco, V. M. S.; Gallego, M. C.

    2015-05-01

    Aims: The Maunder minimum (MM) of greatly reduced solar activity took place in 1645-1715, but the exact level of sunspot activity is uncertain because it is based, to a large extent, on historical generic statements of the absence of spots on the Sun. Using a conservative approach, we aim to assess the level and length of solar cycle during the MM on the basis of direct historical records by astronomers of that time. Methods: A database of the active and inactive days (days with and without recorded sunspots on the solar disc) is constructed for three models of different levels of conservatism (loose, optimum, and strict models) regarding generic no-spot records. We used the active day fraction to estimate the group sunspot number during the MM. Results: A clear cyclic variability is found throughout the MM with peaks at around 1655-1657, 1675, 1684, 1705, and possibly 1666, with the active-day fraction not exceeding 0.2, 0.3, or 0.4 during the core MM, for the three models. Estimated sunspot numbers are found to be very low in accordance with a grand minimum of solar activity. Conclusions: For the core MM (1650-1700), we have found that (1) A large portion of no-spot records, which correspond to the solar meridian observations, may be unreliable in the conventional database. (2) The active-day fraction remained low (below 0.3-0.4) throughout the MM, indicating the low level of sunspot activity. (3) The solar cycle appears clearly during the core MM. (4) The length of the solar cycle during the core MM appears for 9 ± 1 years, but this is uncertain. (5) The magnitude of the sunspot cycle during MM is assessed to be below 5-10 in sunspot numbers. A hypothesis of the high solar cycles during the MM is not confirmed.

  5. Stratospheric influence on the seasonal cycle of nitrous oxide in the troposphere as deduced from aircraft observations and model simulations

    NASA Astrophysics Data System (ADS)

    Ishijima, Kentaro; Patra, Prabir K.; Takigawa, Masayuki; Machida, Toshinobu; Matsueda, Hidekazu; Sawa, Yosuke; Steele, L. Paul; Krummel, Paul B.; Langenfelds, Ray L.; Aoki, Shuji; Nakazawa, Takakiyo

    2010-10-01

    The atmospheric N2O variations between the Earth's surface and the lower stratosphere, simulated by an atmospheric general circulation model-based chemistry transport model (ACTM), are compared with aircraft and satellite observations. We validate the newly developed ACTM simulations of N2O for loss rate and transport in the stratosphere using satellite observations from the Aura Microwave Limb Sounder (Aura-MLS), with optimized surface fluxes for reproducing N2O trends observed at the surface stations. Observations in the upper troposphere/lower stratosphere (UT/LS) obtained by the Japan AirLines commercial flights commuting between Narita (36°N), Japan, and Sydney (34°S), Australia, have been used to study the role of stratosphere-troposphere exchange (STE) on N2O variability near the tropopause. Low N2O concentration events in the UT region are shown to be captured statistically significantly by the ACTM simulation. This is attributed to successful reproduction of stratospheric air intrusion events and N2O vertical/horizontal gradients in the lower stratosphere. The meteorological fields and N2O concentrations reproduced in the ACTM are used to illustrate the mechanisms of STE and subsequent downward propagation of N2O-depleted stratospheric air in the troposphere. Aircraft observations of N2O vertical profile over Surgut (West Siberia, Russia; 61°N), Sendai-Fukuoka (Japan; 34°N-38°N), and Cape Grim (Tasmania, Australia; 41°S) have been used to estimate the relative contribution of surface fluxes, transport seasonality in the troposphere, and STE to N2O seasonal cycles at different altitude levels. Stratospheric N2O tracers are incorporated in the ACTM for quantitative estimation of the stratospheric influence on tropospheric N2O. The results suggest strong latitude dependency of the stratospheric contribution to the tropospheric N2O seasonal cycle. The periods of seasonal minimum in the upper troposphere, which are spring over Japan and summer over Surgut, are in good agreement between the ACTM and observation and indicate a different propagation path of the stratospheric signal between the two sites in the Northern Hemisphere. The stratospheric tracer simulations, when utilized with the observed seasonal cycle, also provide qualitative information on the seasonal variation in surface fluxes of N2O.

  6. Anisotropy of the neutral gas distribution of Comet Halley deduced from NGE/Vega 1 measurements. [Neutral Gas Experiment (NGE)

    NASA Technical Reports Server (NTRS)

    Hsieh, K. C.; Eip, WING-H. AFKEPPLER, E. agrichter, a. k; Eip, WING-H. AFKEPPLER, E. agrichter, a. k

    1986-01-01

    The neutral gas density profile of comet Halley measured by the Neutral Gas Experiment on Vega 1 showed an asymmetry between the inbound and the outbound legs during the fly-by on 6 March 1986. The implications of this asymmetry are discussed, and it is shown how the asymmetry detected by NGE on Vega 1 can be traced back to regions on or near the nucleus to obtain their relative gas production activities at specific times of emission.

  7. Culinary Herbs and Spices: Their Bioactive Properties, the Contribution of Polyphenols and the Challenges in Deducing Their True Health Benefits

    PubMed Central

    Opara, Elizabeth I.; Chohan, Magali

    2014-01-01

    Herbs and spices have been used for both culinary and medicinal purposes for centuries. Over the last decade, research into their role as contributors of dietary polyphenols, known to possess a number of properties associated with reducing the risk of developing chronic non-communicable diseases, has increased. However, bearing in mind how these foods are consumed, normally in small quantities and in combination with other foods, it is unclear what their true benefit is from a health perspective. The aim of this review is to use the literature to discuss how preparative and digestive processes, bioavailability and interactions between foods may influence the bioactive properties of these foods, and whether or not polyphenols are responsible for these properties. Furthermore, this review aims to highlight the challenges that need to be addressed so as to determine the true benefits of these foods and the mechanisms of action that underpin their purported efficacy. PMID:25340982

  8. Multi-scale Holocene Asian monsoon variability deduced from a twin-stalagmite record in southwestern China

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Wang, Yongjin; Cheng, Hai; Edwards, Richard Lawrence; Shen, Chuan-Chou; Liu, Dianbing; Shao, Qingfeng; Deng, Chao; Zhang, Zhenqiu; Wang, Quan

    2016-07-01

    We present two isotopic (δ18O and δ13C) sequences of a twin-stalagmite from Zhuliuping Cave, southwestern China, with 230Th dates from 14.6 to 4.6 ka. The stalagmite δ18O record characterizes orbital- to decadal-scale variability of Asian summer monsoon (ASM) intensity, with the Holocene optimum period (HOP) between 9.8 and 6.8 ka BP which is reinforced by its co-varying δ13C data. The large multi-decadal scale amplitude of the cave δ18O indicates its high sensitivity to climate change. Four centennial-scale weak ASM events during the early Holocene are centered at 11.2, 10.8, 9.1 and 8.2 ka. They can be correlated to cold periods in the northern high latitudes, possibly resulting from rapid dynamics of atmospheric circulation associated with North Atlantic cooling. The 8.2 ka event has an amplitude more than two-thirds that of the Younger Dryas (YD), and is significantly stronger than other cave records in the Asia monsoon region, likely indicating a more severe dry climate condition at the cave site. At the end of the YD event, the δ13C record lags the δ18O record by 300-500 yr, suggesting a multi-centennial slow response of vegetation and soil processes to monsoon enhancement.

  9. Changes in the earth's rate of rotation between A.D. 1672 and 1806 as deduced from solar eclipse timings

    NASA Technical Reports Server (NTRS)

    Stephenson, F. R.; Lieske, J. H.

    1988-01-01

    Solar eclipse timings measured between A.D. 1672 and 1806 are analyzed to study the variation of Delta T (= ET - UT) over this interval. These solar eclipse observations confirm the results of Brouwer (1952), Martin (1969), and Stephenson and Morrison (1969) which were obtained from the analysis of occultations in this period. It is believed that Goldstein's (1985) analysis inadequately represents the changes in Delta T.

  10. Evolution of tissue-specific keratins as deduced from novel cDNA sequences of the lungfish Protopterus aethiopicus.

    PubMed

    Schaffeld, Michael; Bremer, Miriam; Hunzinger, Christian; Markl, Jürgen

    2005-03-01

    Lungfishes are possibly the closest extant relatives of the land vertebrates (tetrapods). We report here the cDNA and predicted amino acid sequences of 13 different keratins (ten type I and three type II) of the lungfish Protopterus aethiopicus. These keratins include the orthologs of human K8 and K18. The lungfish keratins were also identified in tissue extracts using two-dimensional polyacrylamide gel electrophoresis, keratin blot binding assays and immunoblotting. The identified keratin spots were analyzed by peptide mass fingerprinting which assigned seven sequences (inclusively Protopterus K8 and K18) to their respective protein spot. The peptide mass fingerprints also revealed the fact that the major epidermal type I and type II keratins of this lungfish have not yet been sequenced. Nevertheless, phylogenetic trees constructed from multiple sequence alignments of keratins from lungfish and distantly related vertebrates such as lamprey, shark, trout, frog, and human reveal new insights into the evolution of K8 and K18, and unravel a variety of independent keratin radiation events. PMID:15819414

  11. cDNA and deduced amino acid sequence of human pulmonary surfactant-associated proteolipid SPL(Phe)

    SciTech Connect

    Glasser, S.W.; Korfhagen, T.R.; Weaver, T.; Pilot-Matias, T.; Fox, J.L.; Whitsett, J.A.

    1987-06-01

    Hydrophobic surfactant-associated protein of M/sub r/ 6000-14,000 was isolated from either/ethanol or chloroform/methanol extracts of mammalian pulmonary surfactant. Automated Edman degradation in a gas-phase sequencer showed the major N-terminus of the human low molecular weight protein to be Phe-Pro-Ile-Pro-Leu-Pro-Try-Cys-Trp-Leu-Cys-Arg-Ala-Leu-. Because of the N-terminal phenylalanine, the surfactant protein was designated SPL(Phe). Antiserum generated against hydrophobic surfactant protein(s) from bovine pulmonary surfactant recognized protein of M/sub r/ 6000-14,000 in immunoblot analysis and was used to screen a lambdagt11 expression library constructed from adult human lung poly(A)/sup +/ RNA. This resulted in identification of a 1.4-kilobase cDNA clone that was shown to encode the N-terminus of the surfactant polypeptide SPL(Phe) (Phe-Pro-Ile-Pro-Leu-Pro-) within an open reading frame for a larger protein. Expression of a fused ..beta..-galactosidase-SPL (Phe) gene in Escherichia coli yielded an immunoreactive M/sub r/ 34,000 fusion peptide. Hybrid-arrested translation with the cDNA and immunoprecipitation of (/sup 35/S)methionine-labeled in vitro translation products of human poly(A)/sup +/ RNA with a surfactant polyclonal antibody resulted in identification of a M/sub r/ 40,000 precursor protein. Blot hybridization analysis of electrophoretically fractionated RNA from human lung detected a 2.0-kilobase RNA that was more abundant in adult lung than in fetal lung. These proteins, and specifically SPL(Phe), may therefore be useful for synthesis of replacement surfactants for treatment of hyaline membrane disease in newborn infants or of other surfactant-deficient states.

  12. The Nature of Fault Creep and Weakening in the San Andreas System Deduced from Studies of SAFOD Core (Invited)

    NASA Astrophysics Data System (ADS)

    Moore, D. E.; Rymer, M. J.; Lockner, D. A.

    2013-12-01

    Our understanding of the processes operative at depth in fault zones is severely hampered by the general inability to study the actively deforming fault rocks in situ. One of the main goals of the San Andreas Fault Observatory at Depth (SAFOD), a key component of Earthscope, was the recovery of core to allow petrographic, chemical, and physical examination of an active, plate-boundary fault at seismogenic depths, something that had never before been attempted. The SAFOD drill site is located 14 km northwest of Parkfield in central California, along a portion of the San Andreas Fault (SAF) that is characterized by a combination of aseismic slip and microseismicity. Innovations in the design and implementation of SAFOD (summarized in Zoback, Hickman and Ellsworth, Scientific Drilling, No. 11, March 2011) led to the identification of two actively creeping fault traces at 2.65 and 2.70 km vertical depth (~112°C). Subsequent multilateral coring operations successfully sampled the two zones of foliated gouge where creep is localized: the 2.6-m-wide central deforming zone (CDZ) and the 1.6-m-wide southwest deforming zone (SDZ). The two gouge zones are closely similar in character, consisting of porphyroclasts of serpentinite and sedimentary rock dispersed in a fine-grained, foliated matrix of Mg-rich smectitic clays (saponite × corrensite). The boundaries of the CDZ and SDZ with adjoining sedimentary rocks of the Great Valley Group are mineralogically, chemically, and texturally sharp. The Mg-rich clay minerals in the gouge zones are interpreted to be the product of fluid-assisted, shear-enhanced metasomatic reactions between the quartzofeldspathic wall rocks and serpentinite that was tectonically entrained in the SAF from a source in the Coast Range ophiolite. Laboratory friction tests indicate that gouge from the CDZ and SDZ deforms stably (i.e., creeps) at anomalously low levels of shear stress (coefficient of friction, μ ~ 0.15), which is sufficient to explain the long-term weakness of the SAF as inferred from stress and heat flow measurements. At the surface, similar rocks are found in the active trace of the SAF to distances of at least 4 km from SAFOD, and they are inferred to connect to one or both of the gouge zones at depth. The metasomatic reactions identified in the CDZ, SDZ and surface outcrops were duplicated in recent friction tests at hydrothermal conditions, in which serpentinite gouge was sheared slowly for ~15 days between quartz-bearing rocks. The serpentinite gouges in those experiments showed an immediate weakening and stabilization of shear, in contrast to the relatively strong and potentially unstable behavior of serpentinite in an ultramafic chemical system. This suggests that fault creep and weakening along the SAF may have initiated as soon as serpentinite was juxtaposed against crustal rocks. Long-term shear of the serpentinite eventually resulted in even more significant, reaction-induced weakening accompanying creep as Mg-rich clays progressively dominated the mechanical behavior of the SAF (μ ~ 0.05 for pure saponite at 100°C). The results obtained from SAFOD may also be applicable to the other creeping faults of the San Andreas system that are associated with the Coast Range ophiolite.

  13. Extrapolating surface structures to depth in transpressional systems: the role of rheology and convergence angle deduced from analogue experiments

    NASA Astrophysics Data System (ADS)

    Hsieh, Shang Yu; Neubauer, Franz; Cloetingh, Sierd; Willingshofer, Ernst; Sokoutis, Dimitrios

    2014-05-01

    The internal structure of major strike-slip faults is still poorly understood, particularly how the deep structure could be inferred from its surface expression (Molnar and Dayem, 2011 and references therein). Previous analogue experiments suggest that the convergence angle is the most influential factor (Leever et al., 2011). Further analogue modeling may allow a better understanding how to extrapolate surface structures to the subsurface geometry of strike-slip faults. Various scenarios of analogue experiments were designed to represent strike-slip faults in nature from different geological settings. As such key parameters, which are investigated in this study include: (a) the angle of convergence, (b) the thickness of brittle layer, (c) the influence of a rheological weak layer within the crust, and (d) influence of a thick and rheologically weak layer at the base of the crust. The latter aimed to simulate the effect of a hot metamorphic core complex or an alignment of uprising plutons bordered by a transtensional/transpressional strike-slip fault. The experiments are aimed to explain first order structures along major transcurrent strike-slip faults such as the Altyn, Kunlun, San Andrea and Greendale (Darfield earthquake 2010) faults. The preliminary results show that convergence angle significantly influences the overall geometry of the transpressive system with greater convergence angles resulting in wider fault zones and higher elevation. Different positions, densities and viscosities of weak rheological layers have not only different surface expressions but also affect the fault geometry in the subsurface. For instance, rheological weak material in the bottom layer results in stretching when experiment reaches a certain displacement and a buildup of a less segmented, wide positive flower structure. At the surface, a wide fault valley in the middle of the fault zone is the reflection of stretching along the velocity discontinuity at depth. In models with a thin and rheologically weaker layer in the middle of the brittle layer, deformation is distributed over more faults and the geometry of the fault zone below and above the weak zone shows significant differences, suggesting that the correlation of structures across a weak layer has to be supported by geophysical data, which help constraining the geometry of the deep part. This latter experiment has significantly similar phenomena in reality, such as few pressure ridges along Altyn fault. The experimental results underline the need to understand the role of the convergence angle and the influence of rheology on fault evolution, in order to connect between surface deformation and subsurface geometry. References Leever, K. A., Gabrielsen, R. H., Sokoutis, D., Willingshofer, E., 2011. The effect of convergence angle on the kinematic evolution of strain partitioning in transpressional brittle wedges: Insight from analog modeling and high-resolution digital image analysis. Tectonics, 30(2), TC2013. Molnar, P., Dayem, K.E., 2010. Major intracontinental strike-slip faults and contrasts in lithospheric strength. Geosphere, 6, 444-467.

  14. Wintertime haze deterioration in Beijing by industrial pollution deduced from trace metal fingerprints and enhanced health risk by heavy metals.

    PubMed

    Lin, Yu-Chi; Hsu, Shih-Chieh; Chou, Charles C-K; Zhang, Renjian; Wu, Yunfei; Kao, Shuh-Ji; Luo, Li; Huang, Chao-Hao; Lin, Shuen-Hsin; Huang, Yi-Tang

    2016-01-01

    Airborne particulate matter (PM) was collected in Beijing between 24 February and 12 March 2014 to investigate chemical characteristics and potential industrial sources of aerosols along with health risk of haze events. Results showed secondary inorganic aerosol was the major contributor to PM2.5 during haze days. Utilizing specific elements, including Fe, La, Tl and As, as fingerprinting tracers, four emission sources, namely iron and steel manufacturing, petroleum refining, cement plant, and coal combustion were explicitly identified; their elevated contributions to PM during haze days were also estimated. The average cancer risk from exposure to inhalable PM toxic metals was 1.53 × 10(-4) on haze days, which is one order of magnitude higher than in other developed cities. These findings suggested heavy industries emit large amounts of not only primary PM but also precursor gas pollutants, leading to secondary aerosol formation and harm to human health during haze days. PMID:26277049

  15. Atmospheric emissions of N2O deduced from long-term observations at the Mediterranean Island of Lampedusa

    NASA Astrophysics Data System (ADS)

    Artuso, Florinda; Piacentino, Salvatore; Sferlazzo, Damiano; Disarra, Alcide; Meloni, Daniela; Monteleone, Francesco; Chamard, Paolo; Frezzotti, Massimo

    2010-05-01

    Nitrous oxide (N2O) is the third principal long-lived greenhouse gas (GHG) emitted by human activities, as it has been assessed by the last Intergovernmental Panel on Climate Change (IPCC) report. It is produced both naturally and anthropogenically. Natural sources include microbial processes of nitrification and denitrification in soils and water. Use of nitrate and ammonium fertilizers increased noteworthy the emission of N2O from soils. Other anthropogenic sources of N2O are fuel combustion and waste management activities. Its mixing ratio in the atmosphere has considerably risen during the past two centuries as demonstrated by analyses of polar ice cores. Long-term observations of GHG atmospheric concentration are crucial in the investigation of global climate changes and are essential for the prediction of their future trends. For this reason a number of global monitoring studies aimed at determining trends and distribution in the tropospheric abundance of N2O and other GHGs have been carried out during the last years. Scarce information on the magnitude and distribution of N2O emissions is available in the Mediterranean area. In this work we present and analyse long-term N2O records measured at the remote site of Lampedusa Island, located in the middle of the Mediterranean basin. Lampedusa is part of the majors GHG global monitoring programs such as the Global Atmosphere Watch (GAW), established by the World Meteorological Organization, and the National Oceanic and Atmospheric Administration (NOAA) networks. Monitoring of the atmospheric mixing ratio of N2O has been started in Lampedusa in 1996 on a weekly basis but also continuous measurements have been carried out since October 2005. Weekly records are analyzed and the linear trend line has been used to evaluate the annual growth rate. In agreement with data reported by the IPCC 4th Assessment Report, the mean N2O value recorded at Lampedusa in this period is 319.6±0.6 ppb. This finding remarks the representativeness of Lampedusa on global and regional scale. Atmospheric N2O levels have linearly risen at a growth rate of about 0.8 ppb yr-1 and reached in 2008 a mean mixing ratio of 322.5 ppb. Our data mirror the N2O pattern recorded at other global stations located in the Northern Hemisphere. Constraining of source and sink distribution of N2O has been carried out through transport studies and backward trajectory analysis. Records of N2O have been combined with an airmass back-trajectory analysis with the aim to identify possible source regions that lead to elevated N2O mixing ratio at Lampedusa. Results have been compared with the European Environment Agency (EEA) emission database. Preliminary trajectory analysis results show high emissions from Western Europe that are confirmed by the EEA database and can be attributed to fossil fuel combustion and the enhanced microbial production caused by the expansion of the fertilized agricultural lands in this area. The contribution from Northern Africa and Eastern Europe seems to be very low. However N2O emissions from the marine geographical area (Atlantic Ocean and Mediterranean Sea) are elevated confirming the results of recent studies demonstrating that the North Atlantic Ocean is a considerable N2O source.

  16. The uplift of the central High Atlas as deduced from neogene continental sediments of the Ouarzazate province, Morocco

    NASA Astrophysics Data System (ADS)

    Görler, Konrad; Helmdach, Friedrich-Franz; Gaemers, Pieter; Heißig, Kurt; Hinsch, Winfried; Mädler, Karl; Schwarzhans, Werner; Zucht, Monika

    South of the central High Atlas, continental Neogene sediments crop out in the following areas: in a palaeo-drainage system in the Anti-Atlas, in a southern foredeep of the central High Atlas (Ouarzazate basin), and in the intensively folded South Atlas Marginal Zone. The latter two are characterized at the base and the top of the Neogene by thick alluvial-fan sequences and gravitational-glide slabs. They are correlated to episodes of rapid uplift of the axial zone of the High Atlas during Oligocene/Early Miocene and Late Pliocene/Early Pleistocene time. The intermediate sedimentation comprises widespread lake deposits. Charophytes, mollusks, ostracodes, fishes and small mammals from the lacustrine sediments have been studied and their biostratigraphic position (Mellalian/Vallesian to Late Pliocene) has been established. Lithology and the faunas of ostracodes and fishes demonstrate a frequent change of salinity during the lacustrine sedimentation.

  17. The Spatial and Temporal Distribution of Lunar Mare Basalts As Deduced From Analysis of Data for Lunar Meteorites

    NASA Technical Reports Server (NTRS)

    Nyquist, Laurence; Basilevsky, A.; Neukum, G.

    2009-01-01

    In this work we analyze chronological data for lunar meteorites with emphasis on the spatial and temporal distribution of lunar mare basalts. The data are mostly from the Lunar Meteorite Compendium (http://www-curator.jsc.nasa.gov/antmet/lmc/contents.cfm cited thereafter as Compendium) compiled by Kevin Righter and from the associated literature.

  18. Holocene sea-level change and tectonic uplift deduced from raised reef terraces, Kikai-jima, Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Sugihara, Kaoru; Nakamori, Toru; Iryu, Yasufumi; Sasaki, Keiichi; Blanchon, Paul

    Kikai-jima (Kikai Island) is surrounded by four Holocene raised coral reef terraces, which are thought to be an offlapping sequence of reef deposits caused by combined effects of seismic uplift and Holocene sea-level change. Many studies in this region have investigated Holocene sea-level changes and reef growth, but there are relatively few in which reliable sea-level indicators are given. We have found that Pocillopora verrucosa, one of the most abundant coral species on the upper-reef slopes of fringing reefs in the Ryukyus, has its peak abundance at a depth of 1.5 m. Therefore, this species is considered ideal for the analysis of relative sea-level change and can be used as a dipstick for the Holocene reef deposits in this area. Based on the distribution of P. verrucosa on the four Holocene raised terraces, we calculate relative paleo-mean sea levels to be 10.8-11.1 and 8.5-8.9 m for Terrace I, 5.0-5.3 m for Terrace II, 4.0-4.3 m for Terrace III and 1.9-2.5 m for Terrace IV. These results, combined with hitherto known and newly measured radiometric dates (103 total), clearly show that the four terraces formed in response to repeated seismic uplifts at 6.3, 4.1, 3.1 and 1.4 ka, and that sea level was higher than present between 7.0 and 6.3 ka.

  19. Thickness of the oligo-neogene sedimentary cover in the Central Depression, northern Chile (Pampa del Tamarugal, 20°45'-21°30'S), based on seismic reflection

    NASA Astrophysics Data System (ADS)

    Garcia, M.; Simicic, Y.; Contreras Reyes, E.; Charrier, R.

    2013-12-01

    The estimation of the Pampa de Tamarugal oligo-neogene sedimentary cover thickness from seismic interpretation is crucial for scientific and applied subjects, such as placing aquifers traps and Mesozoic-Paleogene basement top location for mining exploration drilling. The Chilean National Petroleum Company (ENAP) has explored hydrocarbon resources in the area, raising several reflection seismic lines and drilling some wells. Previous studies used the paper seismic data by determining the cover geometry and defining the basement-cover boundary. We have obtained directly SGY digital files, which allow a better definition and modeling of stratigraphy and cover thickness. This thickness was estimated by the travel time in the seismic reflection lines and the value of the p-wave propagation velocity (0.91 to 1.97 km/s for cover). The last value was obtained by density measurements of field samples, which resulted from 1,895 to 2,065 g/cm3. In the central-south part of the Pampa del Tamarugal, immediately south of Cerro Challacollo, the west-east-oriented 99_7 seismic line shows a 'basement high' whose top is at 100 m from the surface. The basement was uplift by a north-trend west-verging reverse fault and separates two sub-basins of 9.5 km and 13.8 km wide, and maximum cover thicknesses of 600 and 850 m, west and east respectively. To the north of Cerro Challacollo, the subparallel 99_6 line shows a similar geometry, and increasing the depth of the basement high top up to 350 m in the central part of the section. For seismic lines south of Cerro Challacollo, the basement high disappears and the cover thickness increases. To improve the accuracy of the cover thickness estimations, we will test directly measurements of p-wave propagation velocity in field samples of basement and cover (instead of approximations from the density measurements).

  20. Document d'accompagnement du programme d'education de maternelle: Immersion (Manual in Support of the French Immersion Kindergarten Program).

    ERIC Educational Resources Information Center

    Alberta Learning, Edmonton. Direction de l'education francaise.

    The document is designed for the use by teachers of French immersion Kindergarten programs in Alberta. It aims at outlining the vision, elements, and goals of the program, explaining the role of a French immersion Kindergarten, and providing practical tools for the implementation of the program. Part 1 (Portraits) focuses on how to "read" not only…

  1. Sequence specific molecular recognition by a monocationic lexitropsin of the decadeoxyribonucleotide d-[CATGGCCATG]2: structural and dynamic aspects deduced from high field 1H-NMR studies.

    PubMed Central

    Lee, M; Hartley, J A; Pon, R T; Krowicki, K; Lown, J W

    1988-01-01

    All 1H-NMR resonances of d-[CATGGCCATG]2 and the 1:1 complex of lexitropsin 1 and the DNA were assigned by the NOE difference, COSY and NOESY methods. Addition of 1 causes the base and imino protons for the sequence 5'-CCAT to undergo the most marked drug-induced chemical shift changes, thereby indicating that 1 is located in this base pair sequence. NOEs confirmed the location and orientation of the drug in the 1:1 complex, with the amino terminus oriented to C(6). The van der Waals interaction between H12a,b of 1 and AH2(8) may be responsible for reading of the 3' A.T base pair in the 5'-CCAT sequence. Exchange NMR effects allow an estimate of approximately equal to 62 s-1 for the intramolecular "slide-swing" exchange of the lexitropsin between two equivalent binding sites with delta G = 58 +/- 5 kJ mol-1 at 301 degrees K. PMID:2829134

  2. Document d'accompagnement du programme d'education de maternelle: Francais langue premiere (Manual in Support of the French as a First Language Kindergarten Program).

    ERIC Educational Resources Information